Ahmad Farhan

Environmental Pollution 308 - Contents lists available at ScienceDirect Environmental Pollution journal homepage: www.elsevier.com/locate/envpol Graphene-based nanocomposites and nanohybrids for the abatement of agro-industrial pollutants in aqueous environments☆ Ahmad Farhan a, Ehsan Ullah Rashid a, Muhammad Waqas a, Haroon Ahmad a, Shahid Nawaz b, Junaid Munawar c, Abbas Rahdar d, Sunita Varjani e, Muhammad Bilal f, * a Department of Chemistry, University of Agriculture Faisalabad, 38040, Faisalabad, Pakistan Department of Chemistry, The University of Lahore, Lahore, Pakistan College of Chemistry, Beijing University of Chemical Technology, 100013, China d Department of Physics, University of Zabol, P. O. Box-, Zabol, Iran e Gujarat Pollution Control Board, Gandhinagar, 382 010, Gujarat, India f School of Life Science and Food Engineering, Huaiyin Institute of Technology, Huai’an, 223003, China b c A R T I C L E I N F O A B S T R A C T Keywords: Graphene-based composites Synthesis Functionalization Metal matrix composite Wastewater treatment Antibiotics Pharmaceutical residues Incessant release of a large spectrum of agro-industrial pollutants into environmental matrices remains a serious concern due to their potential health risks to humans and aquatic animals. Existing remediation techniques are unable to remove these pollutants, necessitating the development of novel treatment approaches. Due to its unique structure, physicochemical properties, and broad application potential, graphene has attracted a lot of attention as a new type of two-dimensional nanostructure. Given its chemical stability, large surface area, electron mobility, superior thermal conductivity, and two-dimensional structure, tremendous research has been conducted on graphene and its derived composites for environmental remediation and pollution mitigation. Various methods for graphene functionalization have facilitated the development of different graphene de­ rivatives such as graphene oxide (GO), functional reduced graphene oxide (frGO), and reduced graphene oxide (rGO) with novel attributes for multiple applications. This review provides a comprehensive read on the recent progress of multifunctional graphene-based nanocomposites and nanohybrids as a promising way of removing emerging contaminants from aqueous environments. First, a succinct overview of the fundamental structure, fabrication techniques, and features of graphene-based composites is presented. Following that, graphene and GO functionalization, i.e., covalent bonding, non-covalent, and elemental doping, are discussed. Finally, the environmental potentials of a plethora of graphene-based hybrid nanocomposites for the abatement of organic and inorganic contaminants are thoroughly covered. 1. Introduction Graphene is an sp2 hybridized 2D carbonaceous material with a hexagonal structure discovered in 2004 (Kostya S Novoselov et al., 2004). Robert Curl and colleagues (Curl & Smalley, 1988) developed a C60 product. In a paper published in Nature, Kretschmer et al. (Krätschmer, Lamb, Fostiropoulos, & Huffman, 1990) confirmed the cage structure of C60-fullerene four years later. Carbon nanotubes were discovered by Nippon Electric Company (NEC) Ltd. in 1991, and the carbon material family was enlarged as a result (Iijima, 1991). When Novoselov and colleagues (Kostya S Novoselov et al., 2004) succeeded in separating graphene from its monolithic form using a micro-computer peeling approach in 2004, they raised questions about the level of sci­ entific knowledge of two-dimensional crystals. Graphene with a thick­ ness of 0.34 nm is the thinnest and strongest material (Slonczewski & Weiss, 1958). Many unique properties of graphene, a single-layer carbon sheet with a hexagonal packed lattice structure, have been discovered, including high carrier mobility at room temperature (~10,000 cm2/Vs), the quantum hall effect (QHE), large effective surface morphology (2630 m2/g), high Young’s modulus (B1 TPa), superior optical visibility (~97.7%), and excellent thermal conductivity - W/mK) (Yu et al., 2020a). In the structure of graphene, each carbon atom is This paper has been recommended for acceptance by Su Shiung Lam. * Corresponding author. E-mail addresses:-,-(M. Bilal). ☆ https://doi.org/10.1016/j.envpol- Received 17 February 2022; Received in revised form 28 April 2022; Accepted 28 May 2022 Available online 13 June-/© 2022 Elsevier Ltd. All rights reserved. A. Farhan et al. Environmental Pollution 308 - connected to three other carbon atoms by a link that looks like a hydrogen bond. Due to the electrons’ failure to create connections with the surrounding molecules, the graphene surface will be perpendicular to the remaining p electrons’ bonding direction. The remaining p elec­ trons are more likely to establish a p connection due to their inability to link with the surrounding atoms. A C–C gap of around 0.142 nm be­ tween adjacent graphene atoms has been demonstrated to be remark­ ably stable in the graphene structure (Y. Zhang et al., 2005). The tight connection between each carbon atom in graphene makes the material exceedingly strong. When an external force is applied, the graphene atomic surface deforms and bends to compensate for the atomic sur­ face’s deformation and bendiness. Since the carbon atoms remain in their original positions (Konstantin S Novoselov et al., 2007). On the other hand, they scatter because of extrinsic atom interference or lattice faults in other semiconductors. For scattering, graphene is unaffected by its internal orbit (Kostya S Novoselov et al., 2005). A wide variety of remarkable capabilities are made possible by graphene’s unusual lattice structure, which is a fundamental property of the material. Graphene is produced using a variety of methods, including liquid phase stripping, chemical deposition, mechanical phase stripping, redox processes, and epitaxial growth. After mechanical stripping, the most common methods are chemical vapour deposition, epitaxial growth, and redox processes (V. Singh et al., 2011). Research into carbon-doped graphene quantum dots has only recently emerged as a major focus of scientific investigation (Mehta et al., 2019). The increased properties of graphene-based composite materials have reig­ nited the attention of material scientists in the structural manufacturing of these materials (H.-J. Li et al., 2015a). Studies suggest that using graphene as an additional reinforcement element in composite materials improves their overall properties (Omrani et al., 2016). Since its discovery in 2004, graphene has garnered researchers’ attention for its remarkable mechanical, thermal, electrical, and physi­ cochemical properties (Stoller et al., 2008). The carbonaceous molecule graphene is the only one to exist in two dimensions. Because of the possible applications, these inorganic nanoparticles are being used in composites for this inquiry (Geim, 2009). This material’s potentials use catalytic sensing, electronic energy storage, and energy conversion. To create graphene, a honeycomb lattice carbon sp2 hybridized layer is stacked on top of another layer until it resembles a sheet of paper. This review provides a comprehensive read on the recent progress of multi­ functional graphene-based nanocomposites and nanohybrids as a promising for removing emerging contaminants from aqueous envi­ ronments. First, a succinct overview of the fundamental structure, fabrication techniques, and features of graphene-based composites is presented. Graphene and GO functionalization are discussed, i.e., co­ valent bonding, non-covalent, and elemental doping. Finally, the envi­ ronmental potentials of a plethora of graphene-based hybrid nanocomposites for the abatement of organic and inorganic contami­ nants are thoroughly covered. 2. Synthesis of graphene and its derivatives Due to its low yield in terms of preparation, most research projects have not used graphene in its purest form (pristine graphene). Many graphene derivatives, such as graphene oxide (GO), functional reduced graphene oxide (frGO), and reduced graphene oxide (rGO) are now widely accessible and display many of the same features as graphene. It is best to avoid using “graphene” for these materials because of their heteroatomic irregularities, impurities, and structural flaws (Z. Wei et al., 2010). As far as synthetic methods or tweaks to synthetic tech­ niques used to create rGO are concerned, there has been little devel­ opment since Boehm et al. discovered more than 20 years ago that the suspension could be lowered using various chemical reducing agents, including heat reduction (Dreyer et al., 2010). Different synthetic ap­ proaches for graphene oxide are shown in Fig. 1. Graphite may be oxidized using potassium chlorate (KClO3), a finding made by Nobel laureate chemist Brodie, in conjunction with nitric acid (HNO3). The acidity of the graphite-HNO3 solution was significantly altered due to Staudenmaier’s meticulous attention to detail. As a result, Brodie’s career took a major leap forward. Because the oxidized GO gained importance, the synthesis time was cut by half. It became well recognized when it took so long that the addition of po­ tassium chlorate (and the consequent creation of chlorine dioxide gas) was dangerous. To produce carbon nanotubes (Rosca et al., 2005) and fullerenes, potassium chlorate and nitric acid were successful. Graphene Oxide was produced by modified Hummers’ method by different researchers. Graphite powder and NaNO3 were added to 98% H2SO4 under continuous mechanical stirring. H2SO4 was added to the above solution dropwise under mechanical stirring to facilitate the process further. KMnO4 was added to the solution under an ice bath to start the oxidation process. After obtaining specific coloration, the water was added to it. The reaction was highly exothermic, and the tempera­ ture was maintained at 85–95 ◦ C in an oil bath. In the last step, hydrogen peroxide was added to get GO. This suspension was washed with distilled water many times and centrifuged to attain the neutral pH for GO. The acquired product was ultrasonicated for 20 min, followed by drying at 80 ◦ C for 12 h to get the thin film of GO (Santamaría-Juárez et al., 2020). Fig. 1. Illustration of various approaches for graphene oxide synthesis. 2 A. Farhan et al. Environmental Pollution 308 - Since the modern methods for producing graphene, including micromechanical, chemical vapour deposition (CVD), and epitaxial growth, have grown more prevalent, various variations of these processes have emerged. Recently, graphene on copper foils was exhibited as a roll-toroll innovation. In addition, thermally exfoliated or plasma-assisted CVD graphene powders might be used to produce CNT in bulk quantities comparable to existing large-scale manufacturing procedures. Further­ more, numerous innovative techniques based on liquid-phase micro­ mechanical are being developed to overcome solid-phase micromechanical (Malesevic et al., 2008). Supercritical fluid exfoliation, like liquid-phase exfoliation, was demonstrated by Suchithra et al. (2016). A constant dispersion of sheets was achieved at a 2–4 mg/ml dosage. Supercritical fluid provides advantages in particle size control and homogeneous nanoparticle dispersion throughout the composite with no deficiencies. However, owing to several limitations mentioned by the study’s author (Padmajan Sasikala et al., 2016), it cannot be utilized as a substitute right away. Because of the importance of size and shape, surfactant-free stabilization is a fundamental barrier in graphene production (L. L. Zhang et al., 2010). cut into varied flakes of a few layers. In this technique, van der Waals bonding is used to connect graphene layers firmly. Although it is a basic and straightforward production approach for creating graphene mate­ rials, it is not ideal for large-scale graphene growth (Sinclair et al., 2019). 4.2. Liquid-phase exfoliation Liquid phase exfoliation is a process of producing graphene materials by ultrasonically exfoliating graphite with a solvent such as sulfuric acid, acetic acid or hydrogen peroxide. Because graphite comprises distinct graphene layers bonded by van der Waals forces, sonication is employed in LPE to exfoliate the graphene from the graphite substrate. This approach was utilized to make graphene nanoribbons; however, it is also challenging to manufacture graphene on a big scale (Monajjemi, 2017). 4.3. Pulsed laser deposition (PLD) PLD is a commonly utilized technique of material production that can produce practically any sort of material. The laser energy source is outside the chamber during the PLD process, and the chamber is kept at an ultrahigh vacuum. In this procedure, the material is deposited at a 45◦ angle via stoichiometry transfer between the ablated target and the substrate material. Substrates are placed parallel to the target at a 2–10 mm distance throughout this operation. The main benefit of the PLD technique is the low-temperature development rate, which results in high-quality graphene with no flaws (Kodu et al., 2016) 3. Reduction of GO Reduction causes graphene oxide to return to its original configu­ ration, improving its characteristics, particularly its electrical conduc­ tivity. This is a critical step in enhancing or tailoring the characteristics of GO and possibly altering its structure. RGO has graphene-like fea­ tures, such as high conductivity, but it’s also simple to make in required quantities from inexpensive GO utilizing a number of microwaves, electro-chemical, and photo-assisted thermal processes. RGO has outstanding absorption characteristics throughout the whole spectrum (even a single layer of RGO may absorb a large quantity of light in the visible and near-infrared range). It also has functional groups that might make it dispersible in several solvents. RGO based structures have valuable applications in supercapacitors, sensors, bio-application, ma­ terial strengthening, batteries, catalysts, membranes and environment remediation (Tarcan et al., 2020). Different kinds of reduction methods exist (Chua & Pumera, 2014; X. Gao et al., 2010; Hongtao Liu et al., 2013; Park et al., 2011). Preparation of graphene oxide and reduced graphene oxide on a large scale utilizing a simple and successful tech­ nique in which GO samples are submerged in a chemical reducing agent for a specific time and temperature range. The superfluous functional groups, such as COOH and OH, are removed during this procedure (Chua & Pumera, 2014). Thermal reduction of graphene oxide is also an effective way to get high-performance rGO powders (J. Shen et al., 2009). The GO is decreased in this process by evaporating and burning water molecules and oxygen functional groups at greater temperatures (above or about 1000 ◦ C). This is a powerful reduction method; how­ ever, it can’t keep the GO in a film form (W. Chen et al., 2010; X. Gao et al., 2010; H. Tang et al., 2012; Z. Wei et al., 2010). After being extracted from graphite in the form of a solution, film, or powder, GO is subjected to UV radiation in this process. If the GO powder has to be reduced, it may be dispersed in a solvent since the liquid form absorbs more UV radiation, resulting in a significantly reduced GO (T. Wu et al., 2011). 5. Functionalization strategies for graphene and graphene oxide The appropriate functionalization of graphene and graphene oxide avoids agglomeration and protects their natural characteristics throughout the reduction process (C.-I. Wang et al., 2013). The func­ tional modification of graphene and graphene oxide preserves their remarkable properties while also introducing additional functional groups to offer them new properties. By manipulating the density, localization, and type of flaws in graphene sheets using an appropriate doped, it is possible to control the inherent characteristics of graphene. The physical replacement of a carbon by other atoms (i.e., hetero-atoms) through chemical bond (i.e., substitutional doping) affects the electrical structure and hence the overall intrinsic characteristics of graphene formations. Chemical functionalization of graphene layers by attaching suitable organic/inorganic ions/atoms/molecules through covalent or van der Waals interactions has lately gained a lot of interest since it is less disruptive than the physical replacement of carbon atoms. Because of the gap between the conduction and valence bands, successful func­ tionalization of graphene layers with appropriate chemical species in­ creases solubility and dispersion in various solvents, reduces aggregation, and produces a gap between the conduction and valence bands. Covalently functionalization, non-covalent functionalization, and elemental doping are the most common ways for functionalizing graphene and graphene oxide (Fig. 2) (Bhunia et al., 2012). 5.1. Covalent functionalization 4. Physical fabrication methods of graphene Covalent bonding is being used to reinforce graphene making it more efficient. The presence of oxygen-containing groups on the graphene oxide surface facilitates the functionalization of covalent bonds (Adeel et al., 2018; Noreen et al., 2021). Hydroxyl, carboxyl, and epoxy groups should be abundant on the graphene oxide surface. It may also be used to make isocyanates, carboxylic acid compounds, epoxy ring-openers, and diazotizers (Che Man et al., 2013; Chua & Pumera, 2013; Sinitskii et al., 2010). It is possible to change graphene and graphene oxide by using covalent bonding. A bond adjustment may help you enhance your pro­ cessing power while also taking advantage of new features. GO covalent 4.1. Micromechanical exfoliation Micromechanical exfoliation is a technique of creating graphenebased materials that include peeling pyrolytic graphite in a systemati­ cally ordered pattern using adhesive tape. It is a graphene synthesis technique in which graphene is isolated from graphite crystals throughout the process. Peeling is a technique for obtaining graphene by removing it from graphite. Multi-layer graphene remains on the tape after the peeling is finished. Constantly peeling multi-layer graphene is 3 A. Farhan et al. Environmental Pollution 308 - Fig. 2. Representation of classification of graphene oxide functionalization. Fig. 3. Schematic pathway for the synthesis of polystyrene graft graphite oxide (GO/PS) Reused and modified from Yang et al. (2011) with permission. License Number:- A. Farhan et al. Environmental Pollution 308 - functionalization may be achieved in a variety of ways. Polystyrene particles “armed” with graphene oxide sheets have been used for a number of applications in the past. A Styrene mini-emulsion polymer­ ized into an amphiphilic graphene oxide sheet served as the substrate in the study by (Che Man et al., 2013). It was found that a new method for generating nanoscale graphite oxide sheets from graphite nanofibers with a diameter of around 100 nm worked well. (Namvari et al., 2017) used a new reversible addition-fragmentation chain transfer agent (RAFT-CTA) reduced graphene oxide nanosheets (Cellulose triacetate-reduced graphene oxide nanosheets). Findings were encouraging in using these micro-CTA rGONS to polymerize hy­ drophobic amino acid-based methacrylamide employing a range of monomer/initiator ratios. 5.1.3. Carboxyl groups functionalization Graphene oxide functionalization has attracted much interest because of carboxyl groups at the edges of graphene oxide (F. OuYang et al., 2008). Following carboxyl functionalization, an amino-hydroxyl group is dehydrated, which is performed by heating the group to pro­ duce a bond such as an ester or amide. EDC is made feasible by using a wide range of regularly occurring chemical substances. A few examples are N,N′ -Dicyclohexylcarbodiimide (DCC) (Xiaoming Yang et al., 2011), 2-(7-aza-1H-benzotriazole-1-yl)-1,1,3,3-tetramethyluronium hexa­ fluorophosphate (Y. Xiong et al., 2012) and 1-ethyl-3-(3dimethyl aminopropyl)-carbodiimide (EDC) (Namvari et al., 2017), thionyl chloride (SOCl2). For better conductivity, carboxyl (COOH) groups on semiconducting graphene nanoribbons (GNRs) may chemically func­ tionalize those with the Stone–Wales (SW) defect (F. OuYang et al., 2008). Functionalization of graphene oxide with carboxyl group by different pathways is shown in Fig. 4. COOH mono- and double adsorption may greatly increase electronic properties, which is sensitive to axial concentrations in SW defect COOH pairs (Stone-Wales defects; chemical functionalization; fundamental principles). The material’s behavior changed from semiconducting to p-type metallic when the axial concentration of SWDCPs was elevated. Future nanoelectronic devices and chemical sensors may benefit from graphene nanoribbons (GNRs). 5.1.1. Functionalization of the carbon skeleton – C aromatic ring In contrast to other carbon-based materials, a C– bond is often used in graphene or its oxide to change the carbon skel­ eton. Diels–Alder and graphene oxide diazotization have previously been demonstrated (Bouša et al., 2015; Sinitskii et al., 2010; Xia et al., 2016). To develop a graphene oxide–chitosan composite hydrogel (Jin et al., 2011), heated the graphene in solution to 45 ◦ C, creating a gra­ phene oxide–chitosan composite hydrogel. Azido polyethylene glycol carboxylic acid was used in a click chemistry procedure in concert with other chemicals to establish a different interaction with the carbon skeleton than graphene. Owing to its adaptability and practicality, this approach may be used in a wide range of situations. Deaeration and an electron loss must occur to convert aromatic amines with reactive functional groups into diazo salts or diazo compounds in their basic form (Farquhar, Dykstra, Waterland, Downard, & Brooksby, 2016). Graphene oxide is used to functionally modify the reactive functional groups on graphene, subsequently coupled to an aromatic benzene derivative –C containing reactive functional groups on its surface through a C– addition process. 5.1.2. Hydroxyl functionalization Ester products are often formed from the hydroxyl reaction of amides and isocyanates treated with graphene oxide (Y. Xiong et al., 2012). These esters may be further functionalized with a variety of groups. Graphene oxide’s hydroxyl groups may be esterified and substituted, as proven by (Xiaoming Yang et al., 2011). 2-Bromoisobutyryl bromide, graphene oxide, and 2-Bromoisobutyryl bromide were combined for 48 h before centrifugation separated them. To stabilize the azido-modified graphene oxide (GO–N3) after the esterification process, dime­ thylformamide was used for 24 h as the dispersion medium. A graphene-based polystyrene was formed because of the esterification of polystyrene with alkynes as shown in Fig. 3. The PS length was found to alter the spacing between graphene oxide layers when modified gra­ phene oxide was dissolving in water. Many other graphite polymer composites might benefit from this new process. By crosslinking reduced graphene oxide nanosheets (rGONSs) with the ribofalvintetra cellulose triacetate (RAFT-CTA) through an esterification process, Namvari et al. 5.2. Non-covalent functionalization Non-covalent bond functionalization of graphene or graphene oxide maintains the bulk structure and excellent properties of graphene or graphene oxide while improving stability shown in Fig. 5. Surface noncovalent bond functional modification approaches include p–p bond interaction, hydrogen bonding, ionic bonding, and electrostatic contact. The non-covalent bond functionalization procedure is straightforward and gentle, preserving graphene’s structure and characteristics. How­ ever, this approach introduces additional components (such as surfac­ tants) (Y. Zhou et al., 2019). 5.2.1. p–p bond interaction To achieve high hydrophilicity while simultaneously stripping Fig. 4. Functionalization of graphene oxide with carboxyl group by different pathways. 5 A. Farhan et al. Environmental Pollution 308 - environments. Scientists enhanced the mechanical and barrier characteristics of a starch film by modifying it with reduced graphene oxide (RGO) and sodium dodecyl benzene sulfonate (SDBS). The modified RGO (r-RGO­ hydrophilia)’s was enhanced, resulting in superior dispersion in the oxidized starch (OS) matrix. The tensile strength of the r-RGO-4/OS film rose to 58.5 MPa, about three times that of the OS film (17.2 MPa). The r-RGO/OS film’s water vapour and oxygen barrier characteristics increased significantly compared to the OS and GO/OS films. Further­ more, the r-RGO/OS film could successfully guard against UV light due to its lightproof characteristics. Finally, the r-RGO/OS composite film offers a wide range of possible uses in the packaging business(Ge et al., 2017). Fig. 5. Non-covalent bond functionalization of graphene oxide. 5.2.4. Electrostatic repulsion Another way to increase graphene dispersion is to use electrostatic repulsion between charges of the same sort (Bhunia et al., 2012). employed hydrazine as a reducing agent to regulate the reduction while keeping the carboxyl anion efficiently distributed by charge repulsion and eliminating the functional groups such as hydroxyl groups and epoxy bonds graphene oxide. Water may be used to carry out the chemical conversion of graphene. Because of its negative surface charge, graphene oxide is soluble in water and forms a stable colloidal solution. Ge X. and Li H (D. Li et al., 2008). developed new ecologically-safe Gemini surfactants having two hydrophilic and two hydrophobic groups in each. The epoxidation of the carbon-carbon double bond was carried out in hydrogen peroxide. The spacer group was methylene, and a ring-opening process added the nonionic hydrophilic head group. The surfactants in question were made by reacting chlorine sulfonic acid with hydroxyl esterification. Under the same circumstances, the findings were compared to those of a combination of the conventional surfac­ tant’s sodium decyl sulfate and octaoxyethyleneglycol mono n-decyl ether. The surfactants outperformed the hybrid system in terms of micellization and surface tension reduction. graphite and maintaining the graphene layer on the surface of the ma­ terials, the researchers used a tetradecane derivative with a dendritic polyether branch as a mediator and the synergistic impact of an aro­ matic cyclic fluorene skeleton interacting with graphite and a polyether chain (D.-W. Lee, Kim, & Lee, 2011). This suggests that the planar structure of carbon nanomaterials is crucial in creating effective p-stacking when single-walled carbon nanotubes are treated with the same indole derivative. There seems to be a redshift in the absorption spectra of tetraterpene derivatives and a decrease in fluorescence in­ tensity. The synergistic interface interactions of p–p interaction and hydrogen bonding between graphene oxide (GO) Nanosheets and sul­ fonated styrene-ethylene/butylene–styrene copolymer synthesized with multifunctional benzene produced a super tough artificial nacre inspired by the interfacial interactions of the protein matrix and crystal platelets in nacre. The resulting GO-based artificial nacre had a toughness of 15.3 MJ/m3, which was much higher than natural nacre and other GO-based nanocomposites. The unique nacre’s ultra-tough feature was linked to a synergistic impact between p–p stacking interactions and hydrogen bonding. As a result, this bioinspired synergistic toughening technique paves the way for high-performance GO-based nanocomposites to be built in the near future (P. Song et al., 2017). 5.2.5. Elemental doping Doping in graphene may be altered by various means, including heat treatment, ion bombardment, and arc discharge, to integrate new components. Graphene’s two-dimensional core structure can be pre­ served, while the defects and flaws induced by vacancy formation may be corrected using replacements. Another factor contributing to new capabilities is a shift in surface characteristics (Bai et al., 2009; Xiluan Wang & Shi, 2015; B. Yao et al., 2015). It is possible to alter energy using element doping. According to Duan and colleagues (Duan et al., 2015), annealing graphene with ammonium nitrate increases oxidative phenol degradation by 5.4 times. An investigation has been made on the in­ teractions between graphene doped with B, P, or N. The thermal annealing method may be used to generate N-doped graphene fully. Experimental synthesis of substitutionally doped graphene, which had previously been unattainable using conventional methods, was shown by Wei et al. (D. Wei et al., 2009). This graphene production method is nondestructive and allows for substitutional doping of the carbon atoms because of the recombination of the doped graphene carbon atoms. A wide range of techniques, including SEM, TEM, Raman spectroscopy, XPS (X-ray photoelectron spectroscopy), and EDS (elec­ tron dispersive spectroscopy), were used to confirm the existence of N-doped graphene (Energy-dispersive X-ray spectroscopy). CVD may also be used to make graphene that has been doped with other elements, in addition to non-doped graphene. The electrical characteristics of graphene doped with N were also examined. This discovery leads to the construction of a new kind of graphene, which is important. Electrostatic repulsion is used to make N-doped graphene. 5.2.2. Hydrogen bonding Using hydrogen bonds, he and colleagues investigated the reductioninduced self-organization of reduced graphene oxide aerogel mem­ branes (rGOAMs) (He et al., 2019). PEG–rGO (polyethylene glycol hydrogen bonding interactions) significantly replaced the interlayer a–p and hydrophobic contacts throughout the reduction process, resulting in a smaller 2D stacking rGO laminate and less structural shrinkage in the rGOA networks. A broad range of pores (0.62–0.33 mm) and consider­ able porosity were found in rGOAMs, which contradicted the link be­ tween membrane pore size and porosity previously established (95%). While still maintaining high water flux (up to 4890 L/m2/h1) and impressive antifouling performance, they could reject a wide range of oil-in-water emulsions with a 0.10 bar working pressure. For example, the researchers at Patil et al.(Patil et al., 2009) used hydrogen in­ teractions between graphene and DNA to improve the hydrophilicity of graphene and stabilize it in water. Organic molecules have been deposited on the graphene surface, which may be used in various ap­ plications. As a result of hydrogen bonding, graphene surfaces are functionally modified, which has great biological potential and does not introduce any harmful chemicals into the environment. 5.2.3. Ionic interactions Reduced graphene was dispersed in a range of organic solvents by Choi and colleagues utilizing noncovalent ionic contact functionaliza­ tion with amine-terminated polymers (Choi et al., 2010). Chemically, reduced graphene oxide in an aqueous solution was necessary to pro­ duce reduced graphene sheets. Because of the carboxylate groups found on the graphene surface due to intensive FTIR study, the material has shown outstanding dispersibility in a broad range of organic 6. Types of graphene-based nanocomposites The fabrication and properties of graphene-based nanocomposites 6 Environmental Pollution 308 - A. Farhan et al. depend on their usage and application. This article discusses recent advances in graphene composites, their synthetic method, properties, and application. method and have the highest shielding effectiveness (W.-L. Zhou et al., 2020). Recently electrochemical properties of Gr-based polymer com­ posites were analyzed using different solvents like acetone and acetone-DMF mixtures. Results indicated that the use of DMF affects electrical properties positively (D’Aloia et al., 2018). Graphene-based synthetic polymer composites perform a variety of antimicrobial ac­ tions such as in wound bandages (Cobos et al., 2020), food packing, antibacterial mats, anti-microbial films, and coverings (L. Yu et al., 2013), hydrogels, drug transfer, and water purification (P. Singh et al., 2020). 6.1. Composite of graphene blended with polymeric matrices Blending graphene with polymer matrix forms unique and advanced composites with extraordinary strength, specific modulus, and wide application in biomedical, wastewater treatment, aerospace, and auto­ mobile industries (Du & Cheng, 2012). This section has a comprehensive overview of preparation methods and the latest advancement in graphene-based polymer composites. Blending, solution intercalation, sandwich construction, and molecular–level dispersion of different graphene forms in the polymer matrix (Khan, Hamadneh, & Khan, 2016). Polymeric composites are such constituents that have nano­ particles as strengthening and polymer composites. A nanoparticle can be 1D (fibres and nanotubes), 2D (layered materials such as clay), or 3D (spherical particle). 6.4. Dual polymer-based graphene composites These kinds of composites are used for a variety of applications. Graphene composites made of two different polymers have been used for purification purposes; for example, an ultrafiltration membrane made of HPEI-GO/PES has been created and has shown excellent antibacterial activity. Previously, it was reported that the production of multicomponent-based chitosan chloride-GO (CSCl@GO) nano-composites was modified by a filter medium of quartz-sand (CSCl@GO/QS) might help to reduce bacterial contamination in cooling water systems (Hon­ gyu Liu et al., 2021). The dual functionality of the graphene composites can considerably expand the EMI shielding and thermal managing of the airborne systems while instantaneously decreasing their weight and cost. Recently, sodium alginate/nano fibrillated cellulose double network hydrogel beads have been synthesized with the assistance of graphene oxide. Graphene oxide eases the formation of a double net­ work—the introductory study to improve the existing method to remove the freezing-thawing process. Nano fibrillated cellulose embraces excessive capacity for the water pollution regulator material, as shown in Fig. 7. Polylactide, also known as poly (lactic acid), is a bio-based polymer since it is derived from renewable biomass, such as maize starch, and is thus environmentally friendly. Polylactide exhibits various characteris­ tics, including thermoplasticity, degradability, biocompatibility, and mechanical strength. Although this polymer has certain disadvantages for packaging applications, such as high stiffness, poor heat stability, and low water vapour permeability, it is suitable for other applications (Kumari et al., ). Graphene has been shown in many studies to be a promising material for overcoming the limitations of a wide range of applications. 6.2. Natural polymer-based graphene composites Graphene-based composites with a natural polymer such as poly­ saccharides are easily fabricated. Common examples of polysaccharides blended with graphene are starch, chitosan, alginates, and cellulose (Table 1) (Terzopoulou, Kyzas, & Bikiaris, 2015). Available chitosan with graphene oxide covered with folic acid has recently been developed for delivery of two breast cancer drugs, namely camptothecin (CPT) and 3,3′ -Diindolylmethane (DIM) (Deb et al., 2018). Fig. 6 represents a classification of graphene-based polymer composites. A variety of nanocomposite materials have been made by using different methods. Nanocomposites show modified chemical, mechanical and electrical properties depending on the %age of two-component used (Matos et al., 2014) 6.3. Synthetic polymer-based graphene composites A synthetic polymer is a class of polymers widely used due to their low cost of processing. Recently G-fPANI and G-fPPy have been syn­ thesized by reaction of aniline, pyrrole, and graphene oxide in the presence of phosphoric acid. These nanocomposites showed enhanced flame-retardant features. When the cloth was coated with G-fPANI and G-fPPy, its initial shape was maintained when exposed to fire (Peth­ sangave et al., 2019). Ni/graphene/PDMS foams were made with 3D multi-interface networks by filling graphene foam with Fe3O4@MXene hybrid nanosheets and impregnating PDMS. Cellulose/reduced gra­ phene oxide (RGO)/Fe3O4 aerogels are prepared using the scalable 6.4.1. Graphene-based ceramic composite Over the past ten years, ceramic-based graphene composites have gained in popularity. Aspects of graphene-based ceramic composites’ electrical and mechanical properties, such as surface renewable elec­ trodes (Mohammad-Rezaei, Razmi, & Jabbari, 2014), electronic devices (Eda & Chhowalla, 2009), hip-joint prosthetics (Gutierrez-Gonzalez et al., 2015), and low-temperature fuel cells, have extraordinary po­ tential for use in a variety of functional and structural applications. Ceramics built on ZrB2 graphene can withstand high temperatures and have been utilized in the aerospace sector, including the space shuttle (P. Singh et al., 2020). Other ultrahigh temperature ceramic composites, such as carbides of tantalum (Ta), zirconia (Zr), hafnium (Hf), and niobium (Nb), as well as borides of hafnium, zirconia, and titanium (Ti), are the subject of many research studies (Lahiri et al., 2013). The development of a graphene nanoparticle reinforced ceramic composite under uniaxial pressure utilizing spark plasma has achieved anisotropic electrical, mechanical, and thermal characteristics in the composite. Graphene nanoparticles are better-organized perpendicular to the pressure applied in uniaxial experiments (Tapasztó et al., 2016). Massive research on Al2O3 ceramic composite is being done to discover grain development kinetics and grain refining mechanisms. HP sintered a series of ceramic samples with the same composition at 1600 ◦ C, 1700 ◦ C, and 1750 ◦ C for 5–30 min dwell time. Composites lacking graphene were also produced at 1700 ◦ C sintering temperature Table 1 Recent summary of graphene oxide polysaccharides composites. Gr/biopolymers Synthetic route Advantages Reference GO/BC/chitosan ESM by electrospinning Azarniya et al. (2016) GO/collagen chemical crosslinking Hydrogel by cell microencapsulation Increased tensile strength and modulus Higher bioactivity GO/gelatin GO/Natural rubber Hummer’s method Polysaccharide/ graphene oxide @Fe3O4 hydroxyapatite/ graphene oxide/collagen Solution blending Blending GO increase myogenic differentiation electrical and mechanical properties Both ha combined effect on wastewater treatment Electrodeposition Kanayama et al. (2014) Ege et al. (2017) Domingues et al.(2011) (Z. Wu et al., 2019) Yılmaz et al. (2019) 7 A. Farhan et al. Environmental Pollution 308 - Fig. 6. Classification of graphene polymer-based composites. Fig. 7. Representation of crossing linking of cellulose nanofibers and alginate chain. for 5–30 min to serve as a baseline for comparison. Following HP, the primary phases were Al2O3, tungsten carbide, and (W, Ti) C. Further­ more, throughout the sintering process, graphene not only remained stable but also became homogeneously distributed throughout the ceramic composites (Wang et al., 2021c) characteristics of composites (Güler & Bağcı, 2020). Many methods for producing graphene-reinforced metal matrix composites have been established, including melting and solidification, electrochemical deposition, powder metallurgy, and several new deposition processes. To understand the characteristics of graphene-reinforced metal matrix composites, a variety of metal-based composites have been produced, and their interfacial reactions and microstructures have been observed and investigated (Kostya S Novoselov et al., 2004). 6.4.2. Graphene-reinforced metal matrix composites Graphene is widely regarded as an essential reinforcing element for metal matrix composites, particularly aerospace. The number of articles published in this area over the last decade demonstrates that graphene metal matrix composites have not gotten adequate attention compared to polymer matrix composites in this sector. This may be due to the challenges encountered during the dispersion process and other pro­ cessing concerns such as bonding issues or interfacial chemical in­ teractions. The method of graphene reinforcement may result in flaws and an increase in porosity levels, which directly impact the mechanical 6.4.3. Copper-graphene composites Common graphene alloys offer a broad range of uses due to their high conductivity of electricity and heat and chemical resistance; nevertheless, their mechanical strength falls significantly when heated. We may improve their overall strength by incorporating a secondary component, such as graphene, into copper matrix composites. First re­ ports of copper graphene composites were published in 2013 (Chu & Jia, 8 A. Farhan et al. Environmental Pollution 308 - 2014; J. Liu et al., 2020b). Graphene particles may be incorporated in­ side a copper matrix, and graphene and copper could be stacked in configurations similar to the nanolayered composite structure of mother-of-pearl and other combinations. The exceptional strength of graphene may be given to a composite with a fractional graphene loading by using minute quantities of graphene at 0.00004% by weight. According to the manufacturer, the copper graphene composite has a tensile strength of 1.5 G Pa, half as compared to titanium and three times more potent than aluminum alloys. Composites made of copper and graphene can have hardness up to 93% greater and Young’s moduli up to 65% higher than copper, 230% higher, and tensile strengths up to 48% higher than copper. Even at high temperatures, the hardness and other mechanical characteristics are maintained at a greater level (Chu & Jia, 2014). during the consolidation process, resulting in the formation of Al4C3. By incorporating one wt. % graphene into an Al-matrix composite, the yield and tensile strength were improved by 50% compared to Al-matrix. In the graphene-Al composite, which was produced by high-energy ball milling and vacuums hot pressing, the increase in strength can be attributed to good interfacial bonding, while aluminum carbide Al4C3, which was discovered as a rod-like structure at the interface, is responsible for the increase in strength (Dasari, Morshed, Nouri, Brabazon, & Naher, 2018). Clad rolled graphene-reinforced Cu/Al composites demonstrated a similar improvement in tensile strength and hardness, with 77.5% and 29.1%, respectively, above unclad rolled graphene-reinforced graphene Cu/Al composites. The combined effect of stress transfer and dispersion strengthening was the driving force behind this process (Jiao et al., 2021). Tang et al. announced the development of a Cu-matrix reinforced graphene/Ni composite. It was created via the process of spark plasma sintering. Because of the load transfer process and firm surface contact, the yield strength increased by 94%, and the young’s modulus increased by 61% (H. Tang et al., 2012) due to the boost in strength. 6.4.4. Aluminum-graphene composites As a result of its excellent electrical and thermal conductivity, aluminium is often employed in composite materials (Öztop and Gür­ büz, 2017). Aluminum is also a good conductor of heat and electricity, making it an ideal material for a wide range of applications. Metal matrix composites are popular as matrix materials because of the favourable cost-performance ratio. Graphene is often utilized in con­ struction as a reinforcing material due to its unique qualities. Graphene-reinforced aluminium matrix composites have recently gained popularity among scientists in this sector, who prefer them to standard aluminium matrix composites. A single graphene sheet that is defect-free achieves a fracture strength of 125 GPa. The theoretical calculations suggest that the composite will have a tensile strength of more than 500 MPa since all graphene’s are oriented in the tensile di­ rection. This is not the case, contrary to popular belief. Between 100 and several hundred MPa, estimates of compressive strength are available. Several factors are responsible for this, including more layers in this material, making it weaker than single-layer graphene nanosheets (GNSs). The strength of the final product is reduced by the existence of residual groups in the synthesis. GNSs have a limited influence on strength since they have lower out-of-plane strength than their in-plane strength. In addition to manufacturing techniques, interfacial in­ teractions, and microstructural characteristics, the properties of Al-graphene composites may be affected by these variables. Because they can’t be regulated, Al-graphene composites are only as strong as their weakest component (Y. Gao et al., 2020). 7.2. Corrosion properties Metallic coatings are often used to prevent steel from corrosion in corrosive environments such as high humidity, acidic pH, and extreme temperatures. Following recent research, it was shown that nanoreinforcements might significantly enhance corrosion resistance (Chauhan et al., 2020). A substantial reduction in the corrosion rate was found when a few graphene layers functioned as a corrosion prevention barrier. According to Kumar et al. the graphene/Ni composite coating deposited by the electrodeposition method exhibited excellent perfor­ mance. Using this coating, he reduced the corrosion current generated, suggesting that the coating had more corrosion resistance than the pure Ni coating (S. Kumar et al., 2019). 7.3. Other properties An electrodeposition method was used to create a graphenereinforced nickel composite, which reduces the graphene oxide in the final product. Through the electrodeposition procedure, the nickel growth orientation changed from (200) to (111), indicating a change in the growth direction. A 15% increase in heat conductivity was observed between the graphene/nickel composite and the monolithic nickel (Xiluan Wang & Shi, 2015) relative to the monolithic nickel. The re­ searchers created a hybrid graphene/silver particle filler mixture as a thermal interface material. With a modest loading %age of graphene fillers in the composite, the thermal conductivity of the composite was substantially enhanced. The thermal conductivity of a composite rein­ forced with 5 vol % graphene increased by about fivefold, and the rise in thermal conductivity was attributable to the good intrinsic thermal conductivity of the graphene/silver composite fillers (Tapasztó et al., 2016). 7. Properties of graphene-reinforced metal matrix composites Different Metal Matrix have been incorporated with graphene for enhancing various properties of composite the table below shows different combinations of graphene metal composites and their properties. 7.1. Mechanical properties Nickel (Ni) and nickel alloys are solid and durable metals widely used in high-temperature, harsh settings like combustion engines and turbine blades. The alloying method resulted in nacre-like nickel gra­ phene composites with a 73% increase in strength but a 28% reduction in flexibility. The new structure outlasts the old nickel carbide structure. Even when exposed to high temperatures of up to 1000 ◦ C, the final graphene-derived Ni Ti–Al/Ni3C alloy retained its toughness. The tensile strength of nickel graphene composites may be about 4 GPa, which is 180 times higher than the tensile strength of raw nickel. Scientists have produced Al-graphene composite by incorporating 0.54 wt% graphene into the Al matrix, and this composite demonstrated a 45% and 116% increase in tensile and yield strength, respectively. The yield and tensile strength of the material increased by 228% and 93%, respectively, after extrusion (Park et al., 2008). Another method included the reaction of a tiny quantity of graphene with Al-matrix 8. Hybrid graphene composites The technical, energy, and environmental problems our civilization faces are constantly being redefined in the face of our society’s ongoing development. Companies are always on the lookout for ever-moreefficient materials to better meet market demand while also improving their performance. In designing high-performance produced nano­ composite materials, it is now necessary to consider characteristics such as biodegradability, resistance, lightness, and even flexibility, among other things. With the advancement of science and technology, a large number of composite materials have been developed, each of which has a number of advantages as well as some disadvantages, the majority of which are related to their high toxicity and non-biodegradability, both of which are major limiting factors for their widespread use in the 9 A. Farhan et al. Environmental Pollution 308 - marketplace, as a result of this. Developing innovative alternative ma­ terials that are both ecologically benign and renewable to meet market needs is essential nowadays. According to the researchers, hybrid ma­ terials made of graphene and its derivatives with various nanoparticles are the most promising alternative solution to this problem. It has been well recognized that the development and study of gra­ phene, GO, rGO, and their hybrid derivatives have received significant interest in the research area, both within academia and in the industrial sector. Hybridization is an effective technique that combines graphene nanosheets with nanoparticles such as silver, nano-clays, carbon nano­ tubes, and other materials. The composites that are produced are referred to as hybrid nanocomposites. They can be distinguished by their unique properties and high performance, a combination of both nano­ particles and graphene characterized by their outstanding properties and high performance. Given their remarkable characteristics, hybrid composites have tremendous promise for use in a variety of fields, including engineering, material science, and medicine. They can be used in environmental remediation and energy storage. Graphene is the “material of the future” or the “wonder material.” Since its discovery, the scientific community has shown a significant interest in graphene to determine its characteristics and the source of those capabilities. For a wide range of nanoparticles, such as ferrite, silver, gold nanoparticles, nano-clays, and a variety of others, graphene has the potential to serve as a promising reinforcing agent. The hy­ bridization of these materials may be accomplished via the employment of a variety of ways, each approach being specific to the nanoparticles employed and the circumstances changing from one nanoparticle to another (El Bourakadi, Mekhzoum, & Bouhfid, 2021). Biodegradability, biocompatibility, non-toxicity, and exceptional mechanical character­ istics have all been shown in the hybrid nanocomposite created due to this combination of ingredients. They have demonstrated remarkable biological activity, including antibacterial and anticancer characteristics and outstanding electrochemical properties. In addition, these hybrid composites have been utilized to make probes that detect activity inside cells, contrast agents for medical imaging, and drug transporters that allow for the controlled release of medications. These materials are also utilized to make antibiotics, lithium batteries, electrocatalysts, photo­ catalysts, chemical or biological detection devices, capacitive electrodes for supercapacitors (El Bourakadi et al., 2021), absorbent materials (Bhuyan, Uddin, Bipasha, Islam, & Hossain, 2015) due to their flexibility. nanocomposites have been regarded as a promising hybrid material in nanotechnology with potential uses in various fields. Silver nano parti­ cles are stable. There have been many studies published in the literature on the impact of the combination of silver nanoparticles and graphene on the final characteristics of manufactured materials, and they have all been positive. For example, Ma et al. (Ma et al., 2011) created a novel hybrid nanocomposite for biomedical use by including silver-modified graphene oxide nanosheets into the mix. The materials were effective as an antibacterial agent, particularly against Escherichia coli. 8.1.2. Graphene-carbon nanotubes hybrids Zhou et al. (C. Zhang et al., 2012) utilized a straightforward and ecologically friendly method to produce graphene-CNT aerogels utiliz­ ing a one-step hydrothermal redox reaction as part of their study into creating the next generation of graphene/CNT hybrid materials and their polyvinyl alcohol nanocomposite (Fig. 4). The density ties in the generated aerogels were shallow. Graphene-oxide/CNT mass ratios proportional to the adsorbed organics’ density may attain adsorption abilities proportional to their weight. Particularly. The generated graphene-CNT aerogels showed outstanding reusability and consistency after repeated usage, according to extensive absorption-squeezing and adsorption-combustion experiments. By intercalating reduced graphene oxide with carbon nanotubes in reduced graphene oxide, new hybrid nanofiltration membranes were created (X. Chen et al., 2018) with excellent permeability. The hybrid materials were generated utilizing a simple vacuum-assisted filtration technique, and they were then used to remove nanoparticles, proteins, and colours from water during treat­ ment and purification. Drinking water contains organophosphates and, to a lesser degree, humic acid. 8.1.3. Cellulose nanocrystals/nanofibrils So far, the uses of cellulose have been focused on improving the physical and mechanical properties of hybrid nanocomposites (Cooper et al., 2002). To this end, several scientists are exploring grafting cel­ lulose onto graphite oxide’s surface to enhance the material’s physical, chemical, and thermal characteristics (W. Ouyang et al., 2013). Ac­ cording to Ouyang et al. (W. Ouyang et al., 2013), cellulose was adsorbed on oxidized graphite surfaces through hydrogen bonds formed between the oxygen atoms of graphene oxide’s carboxylic acid function and the hydrogen atoms of cellulose’s hydroxyl function. To produce nanocomposite films using graphene and cellulose, Zhang et al. (C. Zhang et al., 2012) utilized a DMAC/LICI solution for nanocomposites. By utilizing SEM and TEM, the morphology of these hybrid composites was examined. According to scanning electron microscope pictures, graphene was distributed on a nanoscale throughout the cellulose ma­ trix (SEM). Yun and Kim (Yun & Kim, 2009) demonstrated that a covalent bond or, more specifically, an esterification process between graphene oxide’s carboxylic acid functions and cellulose’s hydroxyl functions might also be used to graft cellulose onto graphene oxide or carbon nanotube directly. Produced from the combination, the paper has excellent me­ chanical and performance characteristics. Kafy and colleagues (Kafy et al., 2015) have produced graphene grafted cellulose (Cauli­ flower-fungus-like graphene) nanocomposites for a range of applica­ tions, including energy storage and electrical processes. According to the results of this study, these nanocomposites exhibit a ferroelectric ac­ tivity linked with an incorporated polarization that may change with temperature, as shown by the researchers. Consequently, several char­ acterization methods, including X-ray diffraction, have been used to study grafting. 8.1. Hybrid nanocomposite materials-based graphene To enhance the performance and effectiveness of carbon-based nanomaterials and create custom applications, a variety of hybrid ma­ terials were synthesized. It was developed to improve the performance of carbon nanomaterials by creating GO-allotropic carbon and another GO-nanoparticle and GO-living creature and GO- molecular composites organic. Carbon chemistry has lately made it feasible to combine two allotropes such graphene and carbon nanotube (Parker, Raut, Brown, Stoner, & Glass, 2012), graphene and diamond (Varshney et al., 2011), and carbon nanotube and fullerene (Nasibulin et al., 2007), to build new carbon-based structures. As an alternative, it is possible to graft bioac­ tive molecules onto the surfaces of allotropes such as drugs, peptides, proteins, nucleic acids (Krueger, 2008), or aptamers (Contreras Jiménez et al., 2015), as well as live creatures such as cells, bacteria, or viruses (M. Liu et al., 2011). Most recently, hybrid graphene materials, including metallic nanoparticles (Q. Wang et al., 2012), have been explicitly developed in the rapidly growing area of nanoelectronics. The following is a short review of several significant nanoparticles combined with graphene and its derivatives to prepare a new generation of hybrid materials for functional applications. 8.1.4. Gold nanoparticles A new printable electrochemical sensor contains cubic gold nano­ particles coupled to 2-aminoethanethiol and printed on a flexible sub­ strate. Y. Wang et al. (2011b) discuss the development of a milk tyrosine detection electrode made of functionalized graphene oxide and modified 8.1.1. Graphene-silver nanoparticles nanocomposites Graphene or GO nanocomposites with silver (Ag) nanoparticle 10 A. Farhan et al. Environmental Pollution 308 - glassy carbon. For self-assembling cholinesterase, Wang et al.(Mao et al., 2010) combined gold nanoparticles (Au NPs) with chemically reduced graphene oxide nanosheets to produce a reinforced nanohybrid nano­ composite. Poly (diallyl dimethyl ammonium chloride) was employed as the linker. Enzyme stabilization and paraoxon detection are two appli­ cations where this nanohybrid and nano-assembly design concept has proved useful. Thermally reduced graphene oxide sheets may be coated with a gold nanoparticle (Au NP)-antibody combination to recognize many proteins utilizing an in vitro biosensor. An Au NP-antibody con­ jugate is applied to thermally reduced graphene oxide sheets as part of this method. Combining gold nanoparticles of regulated shape and size with graphene oxide nanosheets distributed in water may create ultra-small gold/graphene nanocomposites used in thermomechanical and thermochemical applications, such as cancer therapy. and graphene nanosheets hybrid nanocomposite materials are further studied in academic and scientific circles. Some of this is attributed to the fact that they have a higher photocatalytic activity and anti-photo corrosion (Peng et al., 2015), very sensitive and flexible gas sensors (Yi et al., 2011), and remarkable photocatalytic performances (X. Li et al., 2013). Because of these features, they may be used in a wide variety of situations. 9. Applications of graphene-based hybrid materials Scientists from all around the globe are intrigued by a range of canted-geometric carbon derivatives, including graphene, graphene oxide, and fullerene, because of these materials’ exceptional mechanical qualities and electrical, optical, and thermal properties. Graphene, graphene oxide, and fullerene are a few examples. Due to their remarkable mechanical, electrical, optical, and thermal capabilities, carbon nanotubes and fullerenes with canted geometric patterns have attracted the attention of scientists and engineers alike (Bilal et al., 2020a). Carbon nanotubes and fullerenes’ mechanical, electrical, opti­ cal, and thermal characteristics with canted geometric patterns are outstanding. There are several uses for the newly discovered composites that range from sensors and actuators to solar cells and data storage in various areas such as healthcare. Hybrid materials consisting of gra­ phene and a variety of nanoparticles have attracted significant interest in recent years owing to their better performance when compared to traditional materials and have been created through a number of tech­ niques. These materials were put to the test in various applications, including preventing the growth of different bacteria strains. These compounds were also screened to see whether they had any anticancer properties (Gurunathan et al., 2015). The nature of the nanostructures and the kinds of nanostructures employed during the hybridization process are often linked to the type of application of a hybrid nano­ composite. Additionally, the method used in the fabrication can impact the results and the direction in which the materials are applied. Fig. 8 depicts the most critical functional uses of graphene-based hybrid ma­ terials that include a variety of various nanoparticles. The hybrid composite outperformed Bi2O3 and Bi2O3/Cu-MOF in photocatalytic activity driven by visible light, owing to the creation of Bi2O3/MOF/GO composites, including GO with high conductivity and MOF with adsorption effect during photodegradation. This synergistic action aids in photo-generated carrier transfer and separation. The Bi2O3/MOF/GO recycles well in the cyclic experiment. This study may pave the way for high-efficiency semiconductor/MOF composites for real-time wastewater treatment and environmental protection (Y. Chen, Zhai, Liang, & Li, 2020). TEM and XPS verified the efficient graphene oxide integration into the amino-grafted TiO2 structure. Graphene oxide and amino-grafted titania interacted chemically. Graphene oxide did not influence the crystalline structure of amino-grafted titania nano­ particles, which was critical for photocatalytic action. Adding amino-grafted TiO2 to graphene oxide changed its photocatalytic ac­ tivity. The photocatalyst with the greatest graphene oxide concentration had the best dye degradation efficiency. The photocatalytic activity of such materials was also affected by irradiation period and organic pollutant type. These results demonstrated the potential benefits of synthesizing graphene-based hybrids, particularly when paired with a well-known photocatalyst (Siwińska-Stefańska et al., 2018). A variety of hybrid composites and their photocatalytic degradation efficiency have been enlisted in Table 2. 8.1.5. Ferrite nanoparticles Aside from biocompatibility, non-toxicity, and simplicity of pro­ duction, the most often utilized graphene oxide-coated ferrite nano­ particles for photocatalytic materials have a number of other desired properties. The combination of Ni0.655 Zn0.35 Fe2O4 nanoparticles, reduced graphene oxide (RGO), and ferrite nanoparticle-coated com­ posites was produced by (Javed et al., 2019). The study’s key goals were to examine the hybrid nanocomposites using SEM and validate the partition of ferrites nanoparticles into graphene sheets. The researchers performed many characterization approaches to validate the successful production of spinel ferrite nanoparticles and composites derived from RGO. These nanohybrids will be examined as a viable alternative to the photodegradation of organic pollutants in wastewater, which is pres­ ently being studied. To remove trace sulfonamides from wastewater, Jianrong Wu et al. (Jianrong Wu et al., 2016) have created RGO-enabled ferrite hybrid materials that might be employed in an adsorption tech­ nique. They started with graphite oxide and metal ions and worked their way up the ladder. 8.1.6. Zinc oxides Metal nanoparticles have sparked a lot of interest in a number of study disciplines, especially biological sciences like antibacterial research, as reinforcing agents in new hybrid materials. They are also used in a number of applications, including the development of novel hybrid materials. Zinc oxide has gained popularity in recent years due to its unique features, including low cost, abundant availability, nontoxicity, and electrochemical activity (Ong et al., 2018). Because of its capacity to carry electricity, ZnO is considered an active battery mate­ rial. This material was developed to integrate the excellent unique fea­ tures of both graphene and zinc oxide. Many methods for producing graphene-zinc oxide hybrid nanocomposites for various applications, on the other hand, have been described in detail. E.R. Ezeigwe et al. (Ezeigwe et al., 2015) created graphene-ZnO hybrid materials using new liquid-phase exfoliation and solvothermal techniques, environmentally friendly and highly competent in their field. The created nano­ composites turned out to be an excellent choice for electrode materials in electrochemical capacitors. ZnO is combined with graphene nano­ sheets in the same context using a low-cost and environmentally friendly method to create a new class of hybrid materials. Jun Wang et al. (J. Wang et al., 2011a) confirmed that incorporating a small number of ZnO particles into a graphene sheet positively affects the final properties of the materials ZnO-graphene, which are particularly useful for energy storage applications supercapacitors. To generate these materials’ photocatalytic properties, scientists recently mixed zinc oxide nanoparticles with reduced graphene oxide (RGO) in a step procedure. The photocatalytic characteristics of these materials may be produced quickly using this process, which is simple, inexpensive, and ecologically friendly. Based on their extensive research, the authors came to the following conclusion. Photocatalyst ZnO-RGO composites were proven to be a promising option for pollutant breakdown and degradation in this study (Zhao et al., 2017). Zinc oxide 10. Methods for synthesizing graphene-based composites Graphene composites are made using a variety of techniques. Table 3 enlists some of these techniques. 11 A. Farhan et al. Environmental Pollution 308 - Fig. 8. Application prospects of graphene-based hybrid materials. Table 2 Different types of Hybrid composites, their photocatalytic degradation efficiency, and their synthesis methods. Hybrid composites Photocatalytic degradation efficiency (%) Pollutant Synthesis method References Ag nanowires/TiO2 nanosheets/graphene Cu3(btc)2/graphene oxide-chitosan (GO-CS@Cu3 (btc)2) Graphene-Ce-TiO2 PW12/CN@Bi2WO6 PANI-TiO2/rGO 71 98 MB MB hydrothermal and calcination solvothermal (C. Liu et al., 2020a) Samuel et al. (2020) - crystal violet Cr(VI) RhB Shende et al.(2018) (R. Yang et al., 2020) (Jing Ma et al., 2020) 99.8 methylene blue Sonochemical Hydrothermal Hydrothermal and polymerization Hydrothermal Reduced graphene oxide/titanate nanotube (rGO/ TNT) resulted in a composite film with a high capacitance of 285 ◦ F and improved rate performance and electrochemical stability. Experimental and computational techniques have been used to deposit copper on epitaxial graphene. This provided insight into the process, and the findings may be utilized to create real-world applications (Shtepliuk et al., 2020). Electrochemical deposition (ECD) is an efficient and pro­ ductive method for film assembly and electrode manufacturing in en­ ergy storage and conversion devices. One of the benefits of ECD is that it enables precise control of the electrochemically deposited layer’s thickness and weight. As a result, the impact of film thickness on capacitive performance was also studied. We discovered that increasing the film thickness did not improve the areal capacitance linearly, which we blamed on resistive electrolyte diffusion via interior pores. Furthermore, mixing electrochemically reduced GO (ErGO) with V2O5 nanoparticles resulted in an excellent capacitance of 168 F/g at 0.1 A/g, owing to the combination of ErGO’s large surface area and V2O5 redox activity (Shtepliuk et al., 2020) Table 3 Various methods for synthesizing graphene-based composites. Composite material Synthetic method load References rGO/PVA rGO/polyaniline PVC/GO Dispersion method In situ method Colloidal blending method Melt spinning Blending – 1% 1% (C. Xiong et al., 2021) (Wu et al.2018b) Mindivan & Göktaş (2020) (Yu et al., 2020b) Serenari et al. (2020) PET/GO Graphene/ polyester GO/Tio2 GO/zirconia Paraffin/ graphene PVDF/GO Hydrothermal method In situ method Chemical reduction 0.1% 3-5 wt % 0.1% – 1% Solution blending – (C. H. Nguyen & Juang, 2019) Garmroudi et al.(2020) (Z.-y. Li et al., 2020) (W. Yang et al., 2018a) (Yuqing Zhao et al., 2019) 10.1. Deposition by electrochemistry 10.2. Thermal spray coating This technique was used to prepare many types of composites, but it has received particular interest in nanocomposite coating due to its cheap cost, ease of handling, and minimal waste production (Baghery et al., 2010). At various temperatures, nickel–graphene composite coatings have been applied. According to data analysis, the temperature of electrodeposition affected surface characteristics, structure, compo­ sition, and thickness. According to research, the thickness of the coating rose to 45◦ before decreasing (Jabbar et al., 2017). Electrochemical deposition of sulfonated graphene and polypyrrole This technique has been used to make a variety of nanocomposite materials with diverse applications. Using a thermal method, graphene oxide (GO) has been introduced into a tungsten carbide-12cobalt matrix. According to the findings, the friction coefficient of graphene oxide was reduced by 28%. In the composite, graphene functioned as a selflubricating agent, reducing the need for lubricants. The advanced hybrid thermal spray technique was recently used to create a tungsten carbide-cobalt graphene nanoparticle composite (WC–Co). The addition 12 A. Farhan et al. Environmental Pollution 308 - of graphene nanoparticles increased porosity, reduced system wear, and tear, and improved overall system performance (Derelizade et al., 2021). Nanoparticles of graphene have been utilized as Nano filler in chrome coatings, which have a broad range of corrosion-resistant applications. It was created using a high-velocity oxy-fuel thermal spray. This is a low-cost technique for incorporating graphene nanoparticles into high-performance materials (Venturi et al., 2020) the resultant solution, which was agitated for 10 min. A specific amount of graphene oxide was added to this solution before pouring it in an autoclave for the hydrothermal process (Phan, Vo, Tran, Luu, & Nguyen, 2019). The hydrothermal approach has been used to remove arsenic from water solutions efficiently. A 50 mL Teflon autoclave sealed with magnesium chloride, aluminium chloride, HMT (hexamethylenetetra­ mine), and GO was heated at 1408 ◦ C for 12 h. Due to the addition of GO, arsenic had a greater maximal elimination capacity (183.1 mg/g) than pure LDH (129.7 mg/g). The LDH/GO composite was more dispersible than the original material, and wrinkled GO was effectively bonded to hexagonal platelet LDH (Wen, Wu, Tan, Wang, & Xu, 2013). A group of researchers reported two-step hydrothermal preparation of Ag nano­ particles modified TiO2 microspheres on reduced graphene oxide (rGO) sheets. The 2% Ag–TiO2-rGO microsphere composite degraded Rhoda­ mine B the fastest, 96% in 100 min. Adding Ag nanoparticles to TiO2 microspheres helps separate photogenerated electron-hole pairs, which are then transported to rGO to participate in photocatalytic processes. The rGO composite enhances the sample’s specific surface area, which is better for dye adsorption (T. Wang et al., 2019b). 10.3. Melting and blending Melt blending has been proven to be a successful method for pre­ paring thermal interface materials. ISP-PN composites have 21.4% higher strength and 28.0% higher mechanical properties than compos­ ites made by direct melt blending(Guo et al., 2021). Melt blending was used to create a graphene-based polymer composite. The thermal and electrical properties of graphene nanoparticles have improved (Plat­ nieks et al., 2020). Using this technique, researchers created graphene polypropylene nanocomposite in a combination of p-xylene and N, N-dimethyl form-amide solvent. They discovered a 43% increase in the young modulus (M. G. Lee et al., 2020). This study used a combination of easy melt mixing and compression moulding to make flexible poly (ether-block-amide) (PEBAX)/graphene composite films. The amount of graphene in a material significantly impacts its mechanical charac­ teristics, electrical conductivity, and Electromechanical impedance (EMI) shielding ability (B. Zhao et al., 2020). 10.6. Solvothermal method Solvothermal method is just like the hydrothermal method, but it uses organic liquid in place of water. A one-step solvothermal technique was used to synthesise rGO/Fe3O4NCs. Solution A was created by dis­ solving 0.15 g graphite oxide and 0.15 g FeCl3.6H2O in 140 mL ethylene glycol using ultrasonication. To make solution B, 0.45 g sodium acetate anhydrous was added to 10 ml ethylene glycol and stirred continuously for 30 min. Then, under steady stirring, solution B is combined with solution A, followed by adding 5 mL of ethylenediamine (EDA) to improve Fe3O4NP homogeneity, and the procedure is repeated for another 30 min to achieve a homogeneous solution. The dark-yellow solution was then transferred to a Teflonlined stainless steel autoclave with a capacity of 200 mL and held at 180 ◦ C for 10 h. After the sol­ vothermal treatment, the black precipitate was centrifuged and washed with water and ethanol before being dried for 24 h in a hot air oven at 70 ◦ C (Vinodhkumar et al., 2020). BiOBr/GO/MOF-5 was prepared by ultrasonically dissolving MOF-5, GO, and BiOBr in 20 mL DMF. Then MOF-5 and GO suspension were added to BiOBr. This was then transported to a Teflon-lined stainlesssteel autoclave. Heat at 160 ◦ C for 24 h, then cool in air. The samples were then collected, cleaned, and dried at 60 ◦ C. This composite was used to degrade rhodamine B dye (Y. Chen et al., 2019). MgFe2O4/Re­ duced Graphene Oxide Composite was prepared by solvothermal method. Mg 1.75 mmol (NO3) 2H2O 3.5 mmol Fe (NO3) 3H2O were sonicated for 30 min and dissolved in 80 ml distilled water. Then, 10 ml of 10 mg/ml GO suspension was added to the solution above and magnetically stirred for 4 h. Ammonia hydroxide raised the pH of the solution to about 10. A Teflon coated stainless steel autoclave (100 ml capacity) was used to sterilise the combination. The autoclave was heated to 180 ◦ C for 12 h and then cooled to ambient temperature. Following multiple washes with ethanol and distilled water, the goods were dried in a vacuum oven at 80 ◦ C overnight (F. Wu et al., 2018a). 10.4. Powdery metallurgy This method has been used to create a variety of graphene compos­ ites. The most common powdered metallurgy technique has been uti­ lized for polymers and ceramic matrix, although metal matrix has lately been employed in research. A graphene 3D network has been integrated into a metal matrix (B. Zhao et al., 2020). Copper is extensively utilized in electronics. However, the usage of simple copper poses a difficulty. A group of scientists addressed this issue by incorporating graphene nanoparticles into a copper matrix, which increased mechanical strength, thermal capability, and performance (Pingale et al., 2020). Additive manufacturing produces mechanically robust, malleable, and highly thermally conductive graphene/aluminum composites. The gra­ phene is uniformly wrapped on the surface of the aluminum powder particles during wet ball milling, which is beneficial for coaxial powder feeding. This is the first time such ductile Al/GnP nanocomposites with excellent strength and stiffness have been reported (T. Wang et al., 2021a). Powder metallurgy aided by sintering in an inert environment was used to produce pure bulk Mg, Magnesium-tin alloy, and Mg–3Sn + 0.2 GN P alloy-nanocomposite. The Mg− 3 Sn alloy graphene composite’s micro hardness, ultimate tensile strength, and maximum compressive strength have been increased by 22.4%, 22.5%, and 20%, respectively (P. Kumar et al.,-. Hydrothermal method Compounds produced under hydrothermal conditions may address the hard agglomeration of some high-temperature preparation proced­ ures. The hydrothermal method is a basic and simple method for pre­ paring graphene-based composites. In this method, water is used as a solvent. High particle purity, tiny size (nano-level), excellent dispersion, uniform distribution, no agglomeration, good controllability, cheap production cost, environmentally benign reaction conditions, and at­ mosphere are all properties of hydrothermally manufactured materials. Furthermore, the hydrothermal approach is a gentle, low-cost, green, and simple-to-use preparation method from an environmental stand­ point (Wang et al. 2021b). The hydrothermal synthesis of TNT/GO was carried out in a Teflon autoclave 150◦ covered by stainless steel at 135 ◦ C for 24 h. To begin, 34 g of NaOH were dissolved in 78 mL of DI water. 0.84 g TiO2 was added to 10.7. Co-precipitation This is an effective method for synthesis of graphene-based com­ posite. The Ag/Fe3O4/graphene nanocomposites were made via reflux­ ing co-precipitation. This was followed by 30 min of sonication to scatter the graphene oxide particles. Separately, 10 ml of distilled water was dissolved with AgNO3, Fe(NO3)3H2O, and PEG6000 (at a 1:1 mol ratio). These were then added to the graphene oxide suspension while swirling magnetically. Shortly after, 10 ml of 0.1% NaBH4 aqueous solution was added to the mixture, refluxing for 180 min at 120 ◦ C. It was then filtered, rinsed with distilled water and ethanol, and dried at room temperature overnight (Amiri et al., 2021). The process of 13 A. Farhan et al. Environmental Pollution 308 - co-precipitation was used to deposit ZnO nanoparticles in the presence of GQDs, resulting in GQD/ZnO composites. To make the final GQDs/ZnO-X composites, we added 1.6 g of sodium hydroxide to the solution and agitated it for 3 h (Hsieh et al., 2022). Reduce graphene oxide/cerium oxide was prepared by the co-precipitation method. This composite showed superior photocatalytic activity and showed an effi­ ciency of 81% for methyl orange degradation (Jayanthi et al., 2018). vs 4.2 eV for TiO2). It’s worth noting that the band bending at the graphene-TiO2 interface may be overlooked owing to their small size. As a result, graphene is an excellent tank for storing photo-induced elec­ trons delivered from TiO2. The role of graphene in different composites has been depicted in Fig. 10 (B. Tang et al., 2018). In a distinctive photodegradation investigation, 0.02 g of either SnO2 or RGOSnO2 photocatalyst sample was combined with 10 ppm RhB solution. By removing the reaction solutions at various time intervals, the absorption spectra were collected to determine residual RhB content. With the RGO-SnO2 photocatalyst sample, deterioration took 25 min under UV light and 50 min under solar light. In an 80-min timeframe, the SnO2 sample displays 70% deterioration under UV radiation and 40% degradation under solar light. Because SnO2 has a large band gap, its activity under solar light is restricted (Fig. 11). The photosensitisation of the RhB molecule is thought to cause the deterioration seen with SnO2 under solar radiation. In all of the following responses, the photo­ sensitisation process contributes almost 20% (Shyamala & Devi, 2020). The stages involved in photocatalytic degradation under UV radiation may be described as follows. The high dissociation energy of the C = O bond (750 kJ mol1) makes photocatalytic CO2 conversion difficult. This mechanism is also linked to the catalyst’s band structure and electron-hole transport. The lack of CO and H2 in the photocatalytic system shows that electron transfer with protons reduces CO2. 8 electrons +8 protons + E◦ redox potential >0.24eV (E◦ = 0.24 V vs NHE) = CH4. For the CO2 reduction to CH4, the defect-induced RT may create electron-hole pairs at the CB and VB. NGO-RT energy band diagram derived using VB-UPS data and Tauc plot band gap value. The energy difference of 0.53 eV between pristine RT (5.01 eV) and NGO-RT (5.54 eV) shows RT bending downward at the NGO-RT composite contact. As seen in Fig. 8a, the ensuing downward band bending enhances interfacial electron transport from the RT CB to the NGO. CO2 molecules adsorb on amorphous RT and the N-site of NGO during photocatalysis. However, the quantity of CH4 evolution in RT is minimal, implying less CO2 adsorption on RT and more on the NGO surface. The establishment of a hydrogen bond between the N func­ tionality and the CO2 molecule has been reported to enhance CO2 cap­ ture in N-doped graphene (Hiragond et al., 2021). 10.8. Sol-gel method In constructing improved catalytic formulations based on graphenebased composites with high structural and compositional uniformity, the sol-gel technique is a promising synthetic approach. This technique includes low-temperature repeatability, chemistry, and high surface to volume ratios. Sol-gel was utilized to make titanium dioxide–graphene oxide thin films. The precursor solution includes titanium isopropoxide, ethanol, hydrofluoric acid (4:32:0.1 M) and graphene oxide, which was added in weight ratios of 1, 3, 5 and 10% to the final powder product. On the other side, the HF was sonicated for 45 min at 45 kHz (100% power, normal mode) in an ELMA TI-H-5 device. The expected titanium iso­ propoxide was added to the remaining ethanol, followed by the original solution prepared with the GO, all under nitrogen and manual stirring. After preparation, the precursor solution was extracted from the inert environment and used to dip–coat prepared glass substrates at 6 cm min− 1. They were then dried at 250 ◦ C for 2 min. The method was repeated 5 times on the substrates, then sintered for 1 h at 450 ◦ C in an air environment (Velasco-Hernández et al., 2020). The one-step sol-gel synthetic technique allowed for simultaneous synthesis of La2Zr2O7 and GO reduction. At 40 min in visible light, the maximal TC removal rate and response rate constant of LZO/rGO are 82.1% and 0.3097 min− 1, respectively. adsorption/photocatalysis synergy of LZO/rGO was better. rGO acts as an electron trap, capturing photogenerated electrons and preventing electron-hole pair recombination (Z. Wang et al., 2020). 11. Charge transfer mechanism between graphene and nanoparticles The photocatalytic charge transfer mechanism of pure TiO2 has been thoroughly investigated in recent years, as shown in Fig. 9. Graphene should be a better material for this than other carbon allotropes since it has maximum electron mobility. Furthermore, photo-generated elec­ trons in TiO2 conduction band would spontaneously migrate into gra­ phene owing to the latter’s higher Fermi level (work function of 4.6 eV Fig. 9. Charge transfer mechanism of TiO2/GO under UV radiation. 14 A. Farhan et al. Environmental Pollution 308 - Fig. 10. Role of graphene in charge transfer in different composites. Fig. 11. Effect of graphene on bandgap of metal under sunlight and UV radiation. Reused and modified from Shyamala & Devi (2020) with permission. License Number-. 12. Environmental remediation potential of graphene-based nanocomposites and chemical businesses have released a range of PCs into surface water. The pollutants in concern include chlorophenols, aminophenols, and nitrophenols. Unusual for this industry is the discovery of PCs in wastewater. It has been a massive issue across the globe for quite some time because of the tremendous toxicity of these compounds, mainly when they are discharged into the environment. PCO (Fu, Dionysiou, & Liu, 2014) is a brand-new advanced oxidation technique (AOT) for degrading organic pollutants. The low toxicity and extraordinary sta­ bility of titanium oxide make it an interesting candidate for use in photocatalysis apart from its well-established role as a semiconductor. 12.1. Degradation of phenolic contaminants Many studies have shown that POPs (phenols, antibiotics, medicines, dyes, and other chemicals) may be broken down into constituent mol­ ecules. Fig. 12 shows the photodegradation of different compounds discussed in this review. Table 4 shows various graphene-based com­ posites used for environmental pollution remediation. Pharmaceutical 15 A. Farhan et al. Environmental Pollution 308 - co-doped TiO2 coupled with rGO (TiO2-x/rGO) at wavelengths larger than 400 nm was successfully explored by Xu et al. (Xu et al., 2018). TiO2 nanoparticles were synthesized and evenly coated on rGO sheets during hydrothermal calcination production. There followed research into how Ti3+ and O vacancies were generated in composites following calcination in an Ar environment, and the findings were published. According to the findings of the activity research, pH = 4.0 was shown to be the optimal pH for the breakdown of BPA. Since Cl− and NO−3 coexist, the breakdown rate of BPA has been considerably slowed down in the environment. For TiO2-x/rGO, BPA degradation rates were 6.16, 2.92, and 2.55, times larger than for pristine TiO2, TiO2/rGO and TiO2-x correspondingly, because of increased visible light harvesting. Lighting and the creation of Ti–O–C bonds were used to achieve this result. Using a hydrothermal treatment and an impregnation approach, Zhang and colleagues (H. Zhang et al., 2015) were able to effectively adorn the surface of TiO2/rGO composite materials with Cu(II) cluster. A conducting medium between TiO2 and Cu (II) clusters existed on rGO, facilitating interfacial charge transfer between the two materials. Because of this experiment, OH concentrations were elevated because of the employment of two-electron transfer to accelerate the breakdown of phenol, which resulted in H2O2 and then O2. An electrochemically produced Cu2O layer was electroplated onto the TiO2 nanotubes to generate the TiO2/Graphene/Cu2O (TiO2/G/Cu2O) hybrid to boost BPA breakdown (L. Yang et al., 2016). Graphene layers were then added to the TiO2 nanotubes. According to a previous study, sandwiched struc­ tures have fast charge transfer and visible light sensitivity, both of which are comparable to those of a “galvanic cell” with low resistance. As Fig. 12. Environmental applications of graphene-based nanocomposites. Table 5 enlists the functioans of graphene-based nanocomposites as absorbents. Many titanium oxide hybrids have been developed to increase ab­ sorption in the visible and near-ultraviolet spectrums (B. Tang et al., 2018). The photodegradation of BPA by Ti3+ and O vacancies (OV) Table 4 Environmental applications of graphene-based composite. Composite Synthesis method Application Reference AgFeO2/Graphene@Cu2(BTC) GO/TIO2 GO/Bentonite rGO/Cu2MoS4 GO/ZnO GO/Ag2CO3/AgBr GO/chitosan–PVA RGO/TiO2/PANCMA NFs GO/Silica/Carbon Nanotubes GO/Attapulgite composite membrane Solvothermal method Solvothermal method Sonication method Hydrothermal method Sonication method Co-precipitation method Blending In situ polymerization Hydrothermal method vacuum-assisted filtration method Removal of pharmaceutical drugs Photocatalytic degradation of MB dye Adsorption of Cu and Ni Degradation of organic pollutant Removal of aluminum and copper ions from wastewater (acid rain drainage) Degradation of organic dye (RhB) and colorless organics (phenol) Removal of Congo red Degradation of malachite green dye and leucomalachite green Dyes from wastewater Removal of heavy metals El-Fawal et al. (2020) (S. Wang et al., 2019a) Chang et al. (2020) Rameshbabu et al. (2017) Rodríguez et al.(2020) Si et al. (2021) Das et al. (2020) (F. Du et al., 2020b) Almoisheer et al. (2019) (W. Liu et al., 2019) Table 5 Graphene based nanocomposites functioning as absorbent. Adsorbent Adsorbate Efficiency (%) Chitosan—Graphene Oxide (GO-CS) Methyl Orange Dialdehyde cellulose grafted graphene oxide(GO-TETADAC) Calcium Alginate/Graphene Oxide (mp-CA/GO) Manganese ferrite/graphene oxide (MFO-GO) Polyamidoamine dendrimer grafted magnetic graphene oxide nanosheets (mGO-PAMAM β-cyclodextrin modified magnetic graphene oxide (β-CD/ MGO) Graphene oxide/poly(3,4-ethylenedioxythiophene):poly (styrenesulfonate) (PEDOT:PSS/GO) Polyethylenimine modified graphene oxide hydrogel ( Synthesis method References 96.6 Hydrothermal Cu (II) and Pb (II) 77 Marcano method Pb2+, Cu2+ and Cd2+ As(V) Methylene blue 95.4, 81.3, and 77.3 96.2 and 95 368.2, 98.1 and-and 177.3 emulsion polymerization Co-precipitation (W. Zhu et al.2020) (M. Yao et al., 2019) Pan et al. (2018) Cd (II), Pb (II) and Cu (II) Pb(II), Cu(II) and methylene blue U(VI) 98.98, 92.59 and-, 82.72 ans 46.89 – 435.85, 326.729 and-, 51.29 and- solvothermal 75–80 602, 374, and 181 – Graphene oxide/SiO2@polyaniline (GO/SiO2@PANI) Pb (II), Hg (II) and Cd (II) Cu(II) and Cr(VI) 98.91 and 97.02 258.27 and 512.47 in–situ Fe3O4-graphene-biochar (GBC- Fe3O4) Crystal violet 82.5 199 Modified facile method Sodium Alginate/Graphene Oxide(GO/SA) Mn (II) 97 56.49 – 16 Adsorption capacity (mg/g) inverse coprecipitation method ball milling method Huong et al. (2018) Peer et al. (2018) (Y.-X. Ma et al., 2018) (Shuang Song et al., 2019) Arshad et al. (2019) (R. Kumar et al., 2020) (C. Du et al., 2020a) (Yang et al., 2018b) A. Farhan et al. Environmental Pollution 308 - shown by TiO2/G/Cu2O losing just 11% of its removal efficiency after five degradation cycles, photo corrosion was successfully prevented because of the insertion of highly conductive graphene into TiO2/­ G/linked Cu2O channels. different disorders. Despite their challenging biodegradability, catalytic oxidation of these organics from wastewater using photocatalysts is effective (Javaid et al., 2021a,b; Rasheed et al., 2020, 2021, 2022; Bilal et al., 2022; Issaka et al., 2022; González-González et al., 2021, 2022; Nascimento et al., 2022). Calza et al. previously showed that reduced graphene oxide-TiO2 (TiO2-rGO) produced through a hydrothermal method had remarkable risperidone degradation and mineralization rates (Calza et al., 2016). Because of its enhanced surface area and adsorption capacity, the best weight ratio of rGO to TiO2 was 1: 5 (TiO2-rGO20), which demonstrated greater photoactivity than TiO2-rGO10 and TiO2. Intriguingly, all samples showed a similar ten­ dency of removal rates in different water sources in the order: distilled water > tap water > river water > lake water, which could be attributed to an increase in organic carbon content and coexisting anions concen­ tration (e.g., CO2− 3 and Cl), which prevented risperidone conversion and competed for % OH, respectively. Monteagudo et al. (Monteagudo et al., 2020) loaded different con­ centrations of rGO onto TiO2 and measured the formation of various ROS in suspensions under solar radiation by removing antipyrine. Zhu and colleagues employed electron-acceptor rGO to alter ZnFe layered double hydroxides using a hydrothermal-calcination technique (J. Zhu et al., 2018). The photocatalytic activity of this composite (ZnFe-CLDH/rGO) was exceptional, with 95% of paracetamol (5 mg L1) destroyed in ZnFe-CLDH/rGO30 solution after 420 min of simulated solar light illumination. The charge transfer resistance of ZnFe-CLDH/rGO30 was much lower than that of ZnFe-CLDH, indicating that rGO caused a better charge transfer efficiency. However, excessive rGO in the composite slowed paracetamol photo degradation. The degrading activities of ZnFe-CLDH/rGO30 did not change significantly in five consecutive runs of the cycling experiment, demonstrating its stability and reusability. 12.2. Degradation of antibiotics Bacterial diseases in humans and animals are increasingly being treated using antibiotics. The use of antibiotics in agriculture is likewise on the rise (M.-f. Li et al., 2019; Soltani et al., 2019). Antibiotics have been found in abundance in aquatic habitats, proving ubiquitous. In addition to causing hearing loss, these medications build up quickly in the human body’s organs and tissues (Bilal et al., 2020b). Toxins such as tetracycline antibiotics (TC), which have been shown to be eliminated from the body through photocatalysis oxidation, have been previously studied. Soltani and colleagues (Soltani et al., 2018) used a visible-light-induced BiVO4/rGO nanocomposite generated using ul­ trasonic techniques to remove triclopyr from a TC-containing solution. With its ability to adsorb and perform photooxidation throughout a pH range of 2.5–10.5, this catalyst’s reduction of Go to RGO was achieved by photocatalytic means at light wavelengths higher than 420 nm. At pH = 10.5 (28–30 ◦ C), it required 90 min to achieve a 99% degrading efficiency. There was a 1.2-fold increase in the activity of the combi­ nation compared to the activity of pure BiVO4 at the same temperature and pH. Soltani and colleagues (Teyyebah Soltani et al., 2018) found that an EG-H2O (v/v = 1:13) solution may be substituted. A 300-W visible light source was used to decompose OTC before the composites were utilized to cover the zeolite and graphene surfaces with TiO2 using the solid dispersion technique (graphene/TiO2/ZSM-5, GTZ) (Hu et al., 2016). The OTC was then degraded using the composites (Xiao et al., 2018). A 0.2 gL1 GTZ solution and 10 mgL1 OTC solution were used for perfor­ mance testing. The homogeneous deposition of TiO2 and ZSM-5 on graphene improved the activity of GTZ composites with the optimal mass ratio of graphene, titanium dioxide, and zeolite (1:8:1). Compared to the optimal mass ratio, GTZ composites were shown to degrade at a rate of 100% in 180 min and remove 78% TOC in 240 min (1:8:1). Hydrothermal methods for manufacturing rGO/CdIn2S4/g-C3N4 ternary composites (rGO/CIS/CN) have been established previously by Xiao and colleagues (Xiao et al., 2018). Researchers discovered that a 30% degradation rate (rGO/30% –CIS/CN) worked best for tetracycline (TC) elimination (0.00766 min1), which was found to be 2.39 times greater than the degradation rates of chloroquine (CN), chloroquine-containing antibiotics (CIS), antibiotics rGO/CN, and of CIS and CIS/CN degrada­ tion (CN). As a bridging medium, researchers at Shen et al. (H. Shen et al., 2017) used an in-situ growth-precipitation technique to secure the NPs of Bi2O3 and Cu2O on rGO. Electrostatic adsorption of Cu(II) cations onto negatively charged Go was followed by a 12-h hydrothermal re­ action with a prepared Bi2O3 sample. This formed the sandwiched structure (rGO-Cu2O/Bi2O3). Lattice fringes of spherical and striped Bi2O3 (100 nm) and Cu2O (100 nm) NPs were determined to be 0.273 nm and 0.245 nm in size after being analyzed after being anchored on rGO and then probed, respectively. The presence of Z-scheme electron transport channels in these composites was shown. As a result, the sandwiched rGO proved its ability to increase the electron transport rate from the CB of Bi2O3 to the VB of Cu2O. After 180 min, the photo­ catalytic effectiveness of TC was 75% higher than the control when compared to rGO-Cu2O/Bi2O3. 12.4. Degradation of toxic dyes Dyeing is becoming an increasingly divisive due to its widespread use and large emissions. In order to efficiently remove dyes and the potentially hazardous aromatic intermediates they create, conventional wastewater treatment methods, such as aerobic bacterial treatment, are inadequate (Ahsan et al., 2021; Aramesh et al., 2021; Khan et al., 2021; Kishor et al., 2021; Nawaz et al., 2022). The photocatalytic oxidation of anthraquinone and azo dyes can be achieved using two-dimensional GR-based catalysts (MB, MO, and RhB). The photocatalytic activity of semiconductors such as Cu2O, Fe2O3, CdS, polyoxometalates, and g-C3N4 was boosted by a factor of two when GR species were used in their synthesis. The photocatalytic potential of these materials was explored. Metal oxide/graphene composites have recently been devel­ oped to speed up the deterioration of MB. Ahmad and colleagues (Ahmad et al., 2018) created a new NiO/GO hybrid with a p-n junction using the in-situ deposition method. MB (50 mg/L) was destroyed in 50 min by the NiO/GO composite, whereas commercial P25 only deterio­ rated 22% in the same period. N-type GO was coupled with p-type NiO to produce an efficient charge transfer and separation heterojunction; second, N-type GO was coupled with p-type NiO to generate an efficient charge transfer and separation heterojunction; and third, N-type GO was associated with ptype NiO to develop an efficient charge transfer and separation hetero­ junction (D. C. T. Nguyen et al., 2017). When exposed to visible light, Nguyen and colleagues found that CuO-GR-TiO2 composites displayed MB-degrading activity when constructed using self-assembly tech­ niques. GR was added to the reaction mixture as the last step to improve activity and stability, resulting in a rise in both h + concentrations and the fraction of oxygen in the MB degradation, as seen in the graph below. According to Liu and colleagues, for 6 h at 180 ◦ C, hydrothermal op­ erations produced corn-like In2O3 and Cu2O octahedra on rGO (J. Liu et al., 2017). Cu2O and In2O3 formed a heterojunction, and oxygen vacancies were 12.3. Degradation of pharmaceutical pollutants Pharmaceuticals comprising non-antibiotic medications (e.g., ris­ peridone, carbamazepine, metronidazole, and paracetamol) have become a substantial class of harmful substances in natural water in recent years have been widely overused for treating and treating 17 ­ A. Farhan et al. Environmental Pollution 308 - produced after being spread over GR sheets by making Cu2O/rGO/In2O3 composites, resulting in a built-in electric field and enhanced charge transfer. The photothermal impact of rGO gave electrons greater addi­ tional energy and a bigger delocalization space to absorb electrons from the CB of In2O3. Cu2O/rGO/In2O3 > Cu2O/rGO > Cu2O > Cu2O > In2O3 > Cu2O/rGO > Cu2O > In2O3 > Cu2O/rGO > Cu2O > In2O3 > Cu2O/ rGO > Cu2O > In2O3 > Cu2O/rGO > Cu2O > In2O3 > Cu2O/rGO > Cu2O > In2O3 > Cu. Scientists have observed that a TiO2/Fe3O4/GO composite degraded MB when exposed to visible light (350–800 nm) (Nadimi et al., 2019). Fe species were made smaller and more evenly dispersed on this ternary system thanks to the help of GR. g-C3N4 (0.00245 min1), GE/CN (0.00574 min1), and 25%-Fe/CN (0.01402 min) degraded 11.28, 4.82, and 1.97 times quicker than g-C3N4 (0.00245 min), GE/CN (0.00574 min), and 25%-Fe/CN (0.01402 min1). MO degradation was greatly accelerated by a photo-Fenton-like reac­ tion, which took just 30 min to complete. These were calculated using GR’s interfacial charge transfer action as an electron mediator, which increased the production of the main active species (h+ and O2%). Tang et al. produced 3D macroscopic g-C3N4 to join with GO via - stacking for easy recycling and outstanding degrading ability (L. Tang et al., 2017). Tong et al. created a 3D porous gC3N4 aerogel to hybridize with GO nanosheets (Tong et al., 2015), which was able to remove 92% of MO in 4 h when exposed to visible light (>420 nm, 0.15 mWcm2). Furthermore, Ag-based composites such as Ag2SO3/AgBr/GO (Wan et al., 2017), Ag2CO3/GO (J. Li et al., 2015b), and Ag/Ag2CO3-rGO (Shaoqing Song et al., 2016) were synthesized and showed high visible-light-induced catalytic activity for MO removal. In the case of RhB degradation, a number of Bi-based catalysts, such as BiOX (X = Cl, I), Bi2WO6, and BiVO4, have been researched and used in practice. Su and colleagues (Su et al., 2018) employed a 50% BiOCl/BiOI/rGO composite to remove RhB (10 mgl1) under visible light (>420 nm). An excellent conductivity of rGO and synergistic effects led to a 90.9% catalytic efficiency in 5 min, double that of BiOCl/BiOI. According to prior research, GO/Bi2WO6 (Su et al., 2018) and Ag/GR/BiVO4 (Xu et al., 2015) were effectively synthesized and used to remove RhB under ambient conditions. Ma et al. (D. Ma et al., 2017) created a Z-scheme g-C3N4/rGO/Bi2 MoO6 photocatalyst and used it to degrade RhB in visible light. As shown in Fig. 14A, rGO formed a ternary system with g-C3N4 and Bi2MoO6. These composites removed RhB 8.73 and 5.19 times faster than Bi2MoO6 and g-C3N4/Bi2MoO6, respectively. Sandwiched rGO was an ideal elec­ tron mediator between photosystem I (Bi2MoO6) and photosystem II (g-C3N4) in a typical Z-scheme system, resulting in improved photo­ catalytic activity. Zhu et al.(Pu et al., 2017) grew TiO2 NPs on rGO (TiO2@rGO) via UV photoreduction. The efficient and straightforward method yielded tiny NPs (27 nm) with an interconnected network and polycrystalline structure. The increased visible light absorption and catalytic activity increased rhodamine 6G degradation over TiO2@rGO by 3.5-times compared to pristine P25 NPs. Meidanchi et al. deposited ZnFe2O4 NPs onto rGO sheets via hydrothermal routes (Meidanchi & Akhavan, 2014) to prevent nanoparticle aggregation during dye adsorption. such as bonds, van der Waals forces, or electrostatic forces, allowing molecules to adhere to them without affecting their chemical or physical characteristics (Ranjan et al., 2019; Teow & Mohammad, 2019). Dangling bonds or functional groups on the basal surface, such as carboxyl or hydroxyl groups, may be used to chemically link organics and CNT/graphene. Although chemical bonding seems to be stronger than physical adsorption, the ratio of these interactions is dependent on the number of functional groups and the surface area involved in the adsorption. Most adsorbates physically attach to CNTs and graphene with virtually flawless structures, and just a handful are absorbed through chemical interactions (Yin et al., 2020). 12.5. Adsorption application of graphene-based composite Adeel, M., Bilal, M., Rasheed, T., Sharma, A., Iqbal, H.M., 2018. Graphene and graphene oxide: functionalization and nano-bio-catalytic system for enzyme immobilization and biotechnological perspective. Int. J. Biol. Macromol. 120,-. Ahmad, J., Majid, K., Dar, M.A., 2018. Controlled synthesis of p-type NiO/n-type GO nanocomposite with enhanced photocatalytic activity and study of temperature effect on the photocatalytic activity of the nanocomposite. Appl. Surf. Sci. 457, 417–426. Ahsan, Z., Kalsoom, U., Bhatti, H.N., Aftab, K., Khalid, N., Bilal, M., 2021. Enzymeassisted bioremediation approach for synthetic dyes and polycyclic aromatic hydrocarbons degradation. J. Basic Microbiol. 61 (11), 960–981. Almoisheer, N., Alseroury, F.A., Kumar, R., Almeelbi, T., Barakat, M., 2019. Synthesis of graphene oxide/silica/carbon nanotubes composite for removal of dyes from wastewater. Earth Syst. Environ. 3 (3), 651–659. Amiri, O., Beshkar, F., Ahmed, S.S., Hamad, B.W., Mahmood, P.H., Dezaye, A.A., 2021. Magnetically-driven Ag/Fe3O4/graphene ternary nanocomposite as efficient photocatalyst for desulfurization of thiophene under visible-light irradiation. Int. J. Hydrogen Energy 46 (38),-. 13. Concluding remarks When graphene derivatives and nanoparticles are mixed, the resulting nanocomposites can enhance graphene derivatives and nano­ particle hybrid materials’ overall properties. Due to their specific properties and chemical structure, a range of nanoparticles (zinc oxide, cellulose nanocrystals/nanofibrils, titanium oxides, and others) may be combined with graphene and its derivatives. The qualities of the hybrid materials produced because of this combination are related to the properties of the graphene used as a reinforcing agent and the properties of the nanostructures utilized, even if they are only a tiny %age of the total quantity of nanostructures used. They are ideal for a variety of functional and practical applications in a variety of fields, including biology and medicine, energy-efficient and environmentally friendly chemicals, electrical devices, and the electrochemical industry. Author’s contributions Ahmad Farhan, Ehsan Ullah Rashid, Muhammad Waqas: Conceptualization, Data analysis and curation, Validation, Writing original draft, review & editing. Haroon Ahmad, Shahid Nawaz, Junaid Munawar: Methodology, Data analysis and curation, Valida­ tion, Writing - review & editing. Ehsan Ullah Rashid, Shahid Nawaz, Abbas Rahdar, Sunita Varjani: Data analysis, Data curation, Writing review & editing. Muhammad Bilal: Software, Supervision, Project administration, Validation, Visualization, Writing - original draft, Writing - review and editing. Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. Acknowledgements The listed author(s) are obliged to their representative universities for providing the literature services. References One of the most promising and dependable methods for eliminating contaminants from wastewater is adsorption. Adsorption can be of two types physical and chemical interactions. The graphene structure is the fundamental building block of all carbon allotropes. Traditional graphite, fullerenes, and carbon nanotubes are all formed by stacking, sealing, and rolling graphene units in some fashion. CNTs and graphene are pure carbon allotropes in which three of the four valence electrons are covalently shared in a two-dimensional plane to create a strong bond, while the fourth valence electron is delocalized among all atoms to produce a weak bond in the third dimension. As a result, CNTs and graphene might develop physical interactions with certain organics, 18 A. Farhan et al. Environmental Pollution 308 - Aramesh, N., Bagheri, A.R., Bilal, M., 2021. Chitosan-based hybrid materials for adsorptive removal of dyes and underlying interaction mechanisms. Int. J. Biol. Macromol. 183, 399–422. Arshad, F., Selvaraj, M., Zain, J., Banat, F., Haija, M.A., 2019. Polyethylenimine modified graphene oxide hydrogel composite as an efficient adsorbent for heavy metal ions. Separ. Purif. Technol. 209, 870–880. Azarniya, A., Eslahi, N., Mahmoudi, N., Simchi, A., 2016. Effect of graphene oxide nanosheets on the physico-mechanical properties of chitosan/bacterial cellulose nanofibrous composites. Compos. Appl. Sci. Manuf. 85, 113–122. Baghery, P., Farzam, M., Mousavi, A., Hosseini, M., 2010. Ni–TiO2 nanocomposite coating with high resistance to corrosion and wear. Surf. Coating. Technol. 204 (23),-. Bai, H., Xu, Y., Zhao, L., Li, C., Shi, G., 2009. Non-covalent functionalization of graphene sheets by sulfonated polyaniline. Chem. Commun. (13),-. Bilal, M., Lam, S.S., Iqbal, H.M., 2022. Biocatalytic remediation of pharmaceutically active micropollutants for environmental sustainability. Environ. Pollut. 293, 118582. Bilal, M., Mehmood, S., Rasheed, T., Iqbal, H.M., 2020b. Antibiotics traces in the aquatic environment: persistence and adverse environmental impact. Curr. Opin. Environ. Sci. Health 13, 68–74. Bilal, M., Nguyen, T.A., Iqbal, H.M., 2020a. Multifunctional carbon nanotubes and their derived nano-constructs for enzyme immobilization–a paradigm shift in biocatalyst design. Coord. Chem. Rev. 422, 213475. Bhunia, P., Hwang, E., Min, M., Lee, J., Seo, S., Some, S., Lee, H., 2012. A non-volatile memory device consisting of graphene oxide covalently functionalized with ionic liquid. Chem. Commun. 48 (6), 913–915. Bhuyan, S., Uddin, N., Bipasha, F.A., Islam, M., Hossain, S., 2015. A review of functionalized graphene properties and its application. Int. J. Innov. Sci. Res. 17 (2), 303–315. Bouša, D., Jankovský, O., Sedmidubský, D., Luxa, J., Šturala, J., Pumera, M., Sofer, Z., 2015. Mesomeric effects of graphene modified with diazonium salts: substituent type and position influence its properties. Chem.–Eur. J. 21 (49),-. Calza, P., Hadjicostas, C., Sakkas, V., Sarro, M., Minero, C., Medana, C., Albanis, T., 2016. Photocatalytic transformation of the antipsychotic drug risperidone in aqueous media on reduced graphene oxide—TiO2 composites. Appl. Catal. B Environ. 183, 96–106. Chang, Y.S., Au, P.I., Mubarak, N.M., Khalid, M., Jagadish, P., Walvekar, R., Abdullah, E. C., 2020. Adsorption of Cu (II) and Ni (II) ions from wastewater onto bentonite and bentonite/GO composite. Environ. Sci. Pollut. Control Ser. 27 (26),-. Chauhan, D.S., Quraishi, M., Ansari, K., Saleh, T.A., 2020. Graphene and graphene oxide as new class of materials for corrosion control and protection: present status and future scenario. Prog. Org. Coating 147, 105741. Che Man, S., Thickett, S.C., Whittaker, M.R., Zetterlund, P.B., 2013. Synthesis of polystyrene nanoparticles “armoured” with nanodimensional graphene oxide sheets by miniemulsion polymerization. J. Polym. Sci. Polym. Chem. 51 (1), 47–58. Chen, W., Yan, L., Bangal, P.R., 2010. Preparation of graphene by the rapid and mild thermal reduction of graphene oxide induced by microwaves. Carbon 48 (4),-. Chen, X., Zou, D., Lin, Y., Zhang, W., Qiu, M., Fan, Y., 2018. Enhanced performance arising from low-temperature preparation of α-alumina membranes via titania doping assisted sol-gel method. J. Membr. Sci. 559, 19–27. Chen, Y., Li, J., Zhai, B., Liang, Y., 2019. Enhanced photocatalytic degradation of RhB by two-dimensional composite photocatalyst. Colloids Surf. A Physicochem. Eng. Asp. 568, 429–435. Chen, Y., Zhai, B., Liang, Y., Li, Y., 2020. Hybrid photocatalysts using semiconductor/ MOF/graphene oxide for superior photodegradation of organic pollutants under visible light. Mater. Sci. Semicond. Process. 107, 104838. Choi, E.-Y., Han, T.H., Hong, J., Kim, J.E., Lee, S.H., Kim, H.W., Kim, S.O., 2010. Noncovalent functionalization of graphene with end-functional polymers. J. Mater. Chem. 20 (10),-. Chu, K., Jia, C., 2014. Enhanced strength in bulk graphene–copper composites. Phys. Status Solidi 211 (1), 184–190. Chua, C.K., Pumera, M., 2013. Covalent chemistry on graphene. Chem. Soc. Rev. 42 (8),-. Chua, C.K., Pumera, M., 2014. Chemical reduction of graphene oxide: a synthetic chemistry viewpoint. Chem. Soc. Rev. 43 (1), 291–312. Cobos, M., De-La-Pinta, I., Quindós, G., Fernández, M.J., Fernández, M.D., 2020. Synthesis, physical, mechanical and antibacterial properties of nanocomposites based on poly (vinyl alcohol)/graphene oxide–silver nanoparticles. Polymers 12 (3), 723. Contreras Jiménez, G.n., Eissa, S., Ng, A., Alhadrami, H., Zourob, M., Siaj, M., 2015. Aptamer-based label-free impedimetric biosensor for detection of progesterone. Anal. Chem. 87 (2),-. Cooper, C.A., Ravich, D., Lips, D., Mayer, J., Wagner, H.D., 2002. Distribution and alignment of carbon nanotubes and nanofibrils in a polymer matrix. Compos. Sci. Technol. 62 (7–8),-. Curl, R.F., Smalley, R.E., 1988. Probing C60. Science 242 (4881),-. D’Aloia, A.G., Proietti, A., Bidsorkhi, H.C., Tamburrano, A., De Bellis, G., Marra, F., Sarto, M.S., 2018. Electrical, mechanical and electromechanical properties of graphene-thermoset polymer composites produced using acetone-DMF solvents. Polymers 10 (1), 82. Das, L., Das, P., Bhowal, A., Bhattachariee, C., 2020. Synthesis of hybrid hydrogel nanopolymer composite using Graphene oxide, Chitosan and PVA and its application in waste water treatment. Environ. Technol. Innovat. 18, 100664. Dasari, B.L., Morshed, M., Nouri, J.M., Brabazon, D., Naher, S., 2018. Mechanical properties of graphene oxide reinforced aluminium matrix composites. Compos. B Eng. 145, 136–144. Deb, A., Andrews, N.G., Raghavan, V., 2018. Natural polymer functionalized graphene oxide for co-delivery of anticancer drugs: in-vitro and in-vivo. Int. J. Biol. Macromol. 113, 515–525. Derelizade, K., Venturi, F., Wellman, R., Kholobysov, A., Hussain, T., 2021. Wear Performance of Graphene Nano Platelets Incorporated WC-Co Coatings Deposited by Hybrid High Velocity Oxy Fuel Thermal Spray. Wear, p. 203974. Domingues, S.H., Salvatierra, R.V., Oliveira, M.M., Zarbin, A.J., 2011. Transparent and conductive thin films of graphene/polyaniline nanocomposites prepared through interfacial polymerization. Chem. Commun. 47 (9),-. Dreyer, D.R., Ruoff, R.S., Bielawski, C.W., 2010. From conception to realization: an historial account of graphene and some perspectives for its future. Angew. Chem. Int. Ed. 49 (49),-. Du, C., Song, Y., Shi, S., Jiang, B., Yang, J., Xiao, S., 2020a. Preparation and characterization of a novel Fe3O4-graphene-biochar composite for crystal violet adsorption. Sci. Total Environ. 711, 134662. Du, F., Sun, L., Huang, Z., Chen, Z., Xu, Z., Ruan, G., Zhao, C., 2020b. Electrospun reduced graphene oxide/TiO2/poly (acrylonitrile-co-maleic acid) composite nanofibers for efficient adsorption and photocatalytic removal of malachite green and leucomalachite green. Chemosphere 239, 124764. Du, J., Cheng, H.M., 2012. The fabrication, properties, and uses of graphene/polymer composites. Macromol. Chem. Phys. 213 (10-11),-. Duan, X., Indrawirawan, S., Sun, H., Wang, S., 2015. Effects of nitrogen-, boron-, and phosphorus-doping or codoping on metal-free graphene catalysis. Catal. Today 249, 184–191. Eda, G., Chhowalla, M., 2009. Graphene-based composite thin films for electronics. Nano Lett. 9 (2), 814–818. Ege, D., Kamali, A.R., Boccaccini, A.R., 2017. Graphene oxide/polymer-based biomaterials. Adv. Eng. Mater. 19 (12),-. El-Fawal, E.M., Younis, S.A., Zaki, T., 2020. Designing AgFeO2-graphene/Cu2 (BTC) 3 MOF heterojunction photocatalysts for enhanced treatment of pharmaceutical wastewater under sunlight. J. Photochem. Photobiol. Chem. 401, 112746. El Bourakadi, K., Mekhzoum, M.E.M., Bouhfid, R., 2021. Generality of Hybridization of Graphene: from Design to Applications Graphene and Nanoparticles Hybrid Nanocomposites. Springer, pp. 1–21. Ezeigwe, E.R., Tan, M.T., Khiew, P.S., Siong, C.W., 2015. One-step green synthesis of graphene/ZnO nanocomposites for electrochemical capacitors. Ceram. Int. 41 (1), 715–724. Farquhar, A.K., Dykstra, H.M., Waterland, M.R., Downard, A.J., Brooksby, P.A., 2016. Spontaneous modification of free-floating few-layer graphene by aryldiazonium ions: electrochemistry, atomic force microscopy, and infrared spectroscopy from grafted films. J. Phys. Chem. C 120 (14),-. Fu, F., Dionysiou, D.D., Liu, H., 2014. The use of zero-valent iron for groundwater remediation and wastewater treatment: a review. J. Hazard Mater. 267, 194–205. Gao, X., Jang, J., Nagase, S., 2010. Hydrazine and thermal reduction of graphene oxide: reaction mechanisms, product structures, and reaction design. J. Phys. Chem. C 114 (2), 832–842. Gao, Y., Zou, J., Wang, X., Yang, J., Li, Z., Li, J., Tang, H., 2020. Mechanical properties of powder metallurgy nickel-based superalloy composite reinforced by low content graphene nanosheets. Adv. Eng. Mater. 22 (7),-. Garmroudi, A., Kheirollahi, M., Mousavi, S.A., Fattahi, M., Mahvelati, E.H., 2020. Effects of Graphene oxide/TiO2 Nanocomposite, Graphene Oxide Nanosheets and Cedr Extraction Solution on IFT Reduction and Ultimate Oil Recovery from a Carbonate Rock. Petroleum. Ge, X., Li, H., Wu, L., Li, P., Mu, X., Jiang, Y., 2017. Improved mechanical and barrier properties of starch film with reduced graphene oxide modified by SDBS. J. Appl. Polym. Sci. 134 (22). Geim, A.K., 2009. Graphene: status and prospects. Science 324 (5934),-. González-González, R.B., Sharma, A., Parra-Saldívar, R., Ramirez-Mendoza, R.A., Bilal, M., Iqbal, H.M., 2021. Decontamination of emerging pharmaceutical pollutants using carbon-dots as robust materials. J. Hazard Mater., 127145 González-González, R.B., Sharma, P., Singh, S.P., Américo-Pinheiro, J.H.P., ParraSaldívar, R., Bilal, M., Iqbal, H.M., 2022. Persistence, Environmental Hazards, and Mitigation of Pharmaceutically Active Residual Contaminants from Water Matrices. Science of The Total Environment, 153329. Güler, Ö., Bağcı, N., 2020. A short review on mechanical properties of graphene reinforced metal matrix composites. J. Mater. Res. Technol. 9 (3),-. Guo, H., Xu, T., Zhou, S., Jiang, F., Jin, L., Song, N., Ding, P., 2021. A technique engineered for improving thermal conductive properties of polyamide-6 composites via hydroxylated boron nitride masterbatch-based melt blending. Compos. B Eng. 212, 108716. Gurunathan, S., Han, J.W., Park, J.H., Kim, E., Choi, Y.-J., Kwon, D.-N., Kim, J.-H., 2015. Reduced graphene oxide–silver nanoparticle nanocomposite: a potential anticancer nanotherapy. Int. J. Nanomed. 10, 6257. Gutierrez-Gonzalez, C.F., Smirnov, A., Centeno, A., Fernández, A., Alonso, B., Rocha, V. G., Bartolome, J., 2015. Wear behavior of graphene/alumina composite. Ceram. Int. 41 (6),-. He, M., Zhang, R., Zhang, K., Liu, Y., Su, Y., Jiang, Z., 2019. Reduced graphene oxide aerogel membranes fabricated through hydrogen bond mediation for highly efficient oil/water separation. J. Mater. Chem. 7 (18),-. Hiragond, C.B., Lee, J., Kim, H., Jung, J.-W., Cho, C.-H., In, S.-I., 2021. A novel N-doped graphene oxide enfolded reduced titania for highly stable and selective gas-phase photocatalytic CO2 reduction into CH4: an in-depth study on the interfacial charge 19 Environmental Pollution 308 - A. Farhan et al. transfer mechanism. Chem. Eng. J. 416, 127978 https://doi.org/10.1016/j. cej-. Hsieh, M.-L., Juang, R.-S., Gandomi, Y.A., Fu, C.-C., Hsieh, C.-T., Liu, W.-R., 2022. Synthesis and characterization of high-performance ZnO/graphene quantum dot composites for photocatalytic degradation of metronidazole. J. Taiwan Inst. Chem. Eng. 131, 104180. Hu, X.-Y., Zhou, K., Chen, B.-Y., Chang, C.-T., 2016. Graphene/TiO2/ZSM-5 composites synthesized by mixture design were used for photocatalytic degradation of oxytetracycline under visible light: mechanism and biotoxicity. Appl. Surf. Sci. 362, 329–334. Huong, P.T.L., Tu, N., Lan, H., Van Quy, N., Tuan, P.A., Dinh, N.X., Le, A.-T., 2018. Functional manganese ferrite/graphene oxide nanocomposites: effects of graphene oxide on the adsorption mechanisms of organic MB dye and inorganic as (V) ions from aqueous solution. RSC Adv. 8 (22),-. Issaka, E., Amu-Darko, J.N.O., Yakubu, S., Fapohunda, F.O., Ali, N., Bilal, M., 2022. Advanced catalytic ozonation for degradation of pharmaceutical pollutants–A review. Chemosphere 289, 133208. Iijima, S., 1991. Helical microtubules of graphitic carbon. Nature 354 (6348), 56–58. Jabbar, A., Yasin, G., Khan, W.Q., Anwar, M.Y., Korai, R.M., Nizam, M.N., Muhyodin, G., 2017. Electrochemical deposition of nickel graphene composite coatings: effect of deposition temperature on its surface morphology and corrosion resistance. RSC Adv. 7 (49),-. Javaid, A., Latif, S., Imran, M., Hussain, N., Bilal, M., Iqbal, H.M., 2021b. MXene-based hybrid composites as photocatalyst for the mitigation of pharmaceuticals. Chemosphere, 133062. Javaid, A., Latif, S., Imran, M., Hussain, N., Rajoka, M.S.R., Iqbal, H.M., Bilal, M., 2021a. Nanohybrids-assisted photocatalytic removal of pharmaceutical pollutants to abate their toxicological effects–A review. Chemosphere, 133056. Javed, H., Rehman, A., Mussadiq, S., Shahid, M., Khan, M.A., Shakir, I., Warsi, M.F., 2019. Reduced graphene oxide-spinel ferrite nano-hybrids as magnetically separable and recyclable visible light driven photocatalyst. Synth. Met. 254, 1–9. Jayanthi, M., Lavanya, T., Saradha, N.A., Satheesh, K., Chenthamarai, S., Jayavel, R., 2018. Superior photocatalytic performance of CeO2 nanoparticles and reduced graphene oxide nanocomposite prepared by low cost Co-precipitation method. J. Nanosci. Nanotechnol. 18 (5),-. Jiao, Z., Wang, Q., Yin, F., Zhang, J., Liu, L., Ji, P., Yu, J., 2021. Novel Laminated MultiLayer graphene/Cu–Al–Mn Composites with Ultrahigh Damping Capacity and Superior Tensile Mechanical Properties. Carbon. Jin, Z., McNicholas, T.P., Shih, C.-J., Wang, Q.H., Paulus, G.L., Hilmer, A.J., Strano, M.S., 2011. Click chemistry on solution-dispersed graphene and monolayer CVD graphene. Chem. Mater. 23 (14),-. Kafy, A., Sadasivuni, K.K., Kim, H.-C., Akther, A., Kim, J., 2015. Designing flexible energy and memory storage materials using cellulose modified graphene oxide nanocomposites. Phys. Chem. Chem. Phys. 17 (8),-. Kanayama, I., Miyaji, H., Takita, H., Nishida, E., Tsuji, M., Fugetsu, B., Akasaka, T., 2014. Comparative study of bioactivity of collagen scaffolds coated with graphene oxide and reduced graphene oxide. Int. J. Nanomed. 9, 3363. Khan, M., Khan, A., Khan, H., Ali, N., Sartaj, S., Malik, S., et al., 2021. Development and characterization of regenerable chitosan-coated nickel selenide nano-photocatalytic system for decontamination of toxic azo dyes. Int. J. Biol. Macromol. 182, 866–878. Khan, W., Hamadneh, N., Khan, W., 2016. Polymer Nanocomposites–Synthesis Techniques, Classification and Properties Science and Applications of Tailored Nanostructures. One Central Press (OCP) [Google Scholar]. Kishor, R., Purchase, D., Saratale, G.D., Ferreira, L.F.R., Bilal, M., Iqbal, H.M., Bharagava, R.N., 2021. Environment friendly degradation and detoxification of Congo red dye and textile industry wastewater by a newly isolated Bacillus cohnni (RKS9). Environ. Technol. Innovat. 22, 101425. Kodu, M., Berholts, A., Kahro, T., Avarmaa, T., Kasikov, A., Niilisk, A., Jaaniso, R., 2016. Highly sensitive NO2 sensors by pulsed laser deposition on graphene. Appl. Phys. Lett. 109 (11), 113108. Krätschmer, W., Lamb, L.D., Fostiropoulos, K., Huffman, D.R., 1990. Solid C 60: a new form of carbon. Nature 347 (6291), 354–358. Krueger, A., 2008. Diamond nanoparticles: jewels for chemistry and physics. Adv. Mater. 20 (12),-. Kumar, P., Skotnicova, K., Mallick, A., Gupta, M., Cegan, T., Jurica, J., 2021. Mechanical characterization of graphene nanoplatelets-reinforced Mg-3Sn alloy synthesized by powder metallurgy. Metals 11 (1), 62. Kumar, R., Barakat, M., Taleb, M.A., Seliem, M.K., 2020. A recyclable multifunctional graphene oxide/SiO2@ polyaniline microspheres composite for Cu (II) and Cr (VI) decontamination from wastewater. J. Clean. Prod. 268, 122290. Kumar, S., Saeed, G., Kim, N.H., Lee, J.H., 2019. Fabrication of Co–Ni–Zn ternary Oxide@ NiWO4 core-shell nanowire arrays and Fe2O3-CNTs@ GF for ultra-highperformance asymmetric supercapacitor. Compos. B Eng. 176, 107223. Kumari, S., Nidhi, M., & Sunkavalli, Y. Chitin Based Bioplastics Production and Insilco Studies Using Optimization Software.. Lahiri, D., Khaleghi, E., Bakshi, S.R., Li, W., Olevsky, E.A., Agarwal, A., 2013. Grapheneinduced strengthening in spark plasma sintered tantalum carbide–nanotube composite. Scripta Mater. 68 (5), 285–288. Lee, D.-W., Kim, T., Lee, M., 2011. An amphiphilic pyrene sheet for selective functionalization of graphene. Chem. Commun. 47 (29),-. Lee, M.G., Lee, S., Cho, J., Jho, J.Y., 2020. Improving dispersion and mechanical properties of polypropylene/graphene nanoplatelet composites by mixed solventassisted melt blending. Macromol. Res. 28 (12),-. Li, D., Müller, M.B., Gilje, S., Kaner, R.B., Wallace, G.G., 2008. Processable aqueous dispersions of graphene nanosheets. Nat. Nanotechnol. 3 (2), 101–105. Li, H.-J., Qian, D.-J., Chen, M., 2015a. Templateless infrared heating process for fabricating carbon nitride nanorods with efficient photocatalytic H2 evolution. ACS Appl. Mater. Interfaces 7 (45),-. Li, J., Wei, L., Yu, C., Fang, W., Xie, Y., Zhou, W., Zhu, L., 2015b. Preparation and characterization of graphene oxide/Ag2CO3 photocatalyst and its visible light photocatalytic activity. Appl. Surf. Sci. 358, 168–174. Li, M.-f., Liu, Y.-g., Zeng, G.-m., Liu, N., Liu, S.-b., 2019. Graphene and graphene-based nanocomposites used for antibiotics removal in water treatment: a review. Chemosphere 226, 360–380. Li, X., Wang, Q., Zhao, Y., Wu, W., Chen, J., Meng, H., 2013. Green synthesis and photocatalytic performances for ZnO-reduced graphene oxide nanocomposites. J. Colloid Interface Sci. 411, 69–75. Li, Z.-y., Cai, Z.-b., Ding, Y., Cui, X.-J., Yang, Z.-b., Zhu, M.-h., 2020. Characterization of graphene oxide/ZrO2 composite coatings deposited on zirconium alloy by micro-arc oxidation. Appl. Surf. Sci. 506, 144928. Liu, C., Lin, Y., Dong, Y., Wu, Y., Bao, Y., Yan, H., Ma, J., 2020a. Fabrication and investigation on Ag nanowires/TiO2 nanosheets/graphene hybrid nanocomposite and its water treatment performance. Adv. Composi. Hybrid Mater. 3 (3), 402–414. Liu, H., Pan, B., Wang, Q., Niu, Y., Tai, Y., Du, X., Zhang, K., 2021. Crucial roles of graphene oxide in preparing alginate/nanofibrillated cellulose double network composites hydrogels. Chemosphere 263, 128240. Liu, H., Zhang, L., Guo, Y., Cheng, C., Yang, L., Jiang, L., Zhu, D., 2013. Reduction of graphene oxide to highly conductive graphene by Lawesson’s reagent and its electrical applications. J. Mater. Chem. C 1 (18),-. Liu, J., Ke, J., Li, D., Sun, H., Liang, P., Duan, X., Wang, S., 2017. Oxygen vacancies in shape controlled Cu2O/reduced graphene oxide/In2O3 hybrid for promoted photocatalytic water oxidation and degradation of environmental pollutants. ACS Appl. Mater. Interfaces 9 (13),-. Liu, J., Sun, K., Zeng, L., Wang, J., Xiao, X., Liu, J., Ding, Y., 2020b. Microstructure and properties of copper–graphite composites fabricated by spark plasma sintering based on two-step mixing. Metals 10 (11), 1506. Liu, M., Yin, X., Ulin-Avila, E., Geng, B., Zentgraf, T., Ju, L., Zhang, X., 2011. A graphenebased broadband optical modulator. Nature 474 (7349), 64–67. Liu, W., Wang, D., Soomro, R.A., Fu, F., Qiao, N., Yu, Y., Xu, B., 2019. Ceramic supported attapulgite-graphene oxide composite membrane for efficient removal of heavy metal contamination. J. Membr. Sci. 591, 117323. Ma, D., Wu, J., Gao, M., Xin, Y., Sun, Y., Ma, T., 2017. Hydrothermal synthesis of an artificial Z-scheme visible light photocatalytic system using reduced graphene oxide as the electron mediator. Chem. Eng. J. 313,-. Ma, J., Dai, J., Duan, Y., Zhang, J., Qiang, L., Xue, J., 2020. Fabrication of PANI-TiO2/ rGO hybrid composites for enhanced photocatalysis of pollutant removal and hydrogen production. Renew. Energy 156,-. Ma, J., Zhang, J., Xiong, Z., Yong, Y., Zhao, X., 2011. Preparation, characterization and antibacterial properties of silver-modified graphene oxide. J. Mater. Chem. 21 (10),-. Ma, Y.-X., Shao, W.-J., Sun, W., Kou, Y.-L., Li, X., Yang, H.-P., 2018. One-step fabrication of β-cyclodextrin modified magnetic graphene oxide nanohybrids for adsorption of Pb (II), Cu (II) and methylene blue in aqueous solutions. Appl. Surf. Sci. 459, 544–553. Malesevic, A., Vitchev, R., Schouteden, K., Volodin, A., Zhang, L., Van Tendeloo, G., Van Haesendonck, C., 2008. Synthesis of few-layer graphene via microwave plasmaenhanced chemical vapour deposition. Nanotechnology 19 (30), 305604. Mao, S., Lu, G., Yu, K., Bo, Z., Chen, J., 2010. Specific protein detection using thermally reduced graphene oxide sheet decorated with gold nanoparticle-antibody conjugates. Adv. Mater. 22 (32),-. Matos, C.F., Galembeck, F., Zarbin, A.J., 2014. Multifunctional and environmentally friendly nanocomposites between natural rubber and graphene or graphene oxide. Carbon 78, 469–479. Mehta, A., Mishra, A., Basu, S., Shetti, N.P., Reddy, K.R., Saleh, T.A., Aminabhavi, T.M., 2019. Band gap tuning and surface modification of carbon dots for sustainable environmental remediation and photocatalytic hydrogen production–A review. J. Environ. Manag. 250, 109486. Meidanchi, A., Akhavan, O., 2014. Superparamagnetic zinc ferrite spinel–graphene nanostructures for fast wastewater purification. Carbon 69, 230–238. Mindivan, F., Göktaş, M., 2020. Preparation of new PVC composite using green reduced graphene oxide and its effects in thermal and mechanical properties. Polym. Bull. 77 (4),-. Mohammad-Rezaei, R., Razmi, H., Jabbari, M., 2014. Graphene ceramic composite as a new kind of surface-renewable electrode: application to the electroanalysis of ascorbic acid. Microchim. Acta 181 (15–16),-. Monajjemi, M., 2017. Liquid-phase exfoliation (LPE) of graphite towards graphene: an ab initio study. J. Mol. Liq. 230, 461–472. Monteagudo, J., Durán, A., Martínez, M., San Martín, I., 2020. Effect of reduced graphene oxide load into TiO2 P25 on the generation of reactive oxygen species in a solar photocatalytic reactor. Application to antipyrine degradation. Chem. Eng. J. 380, 122410. Nadimi, M., Saravani, A.Z., Aroon, M., Pirbazari, A.E., 2019. Photodegradation of methylene blue by a ternary magnetic TiO2/Fe3O4/graphene oxide nanocomposite under visible light. Mater. Chem. Phys. 225, 464–474. Namvari, M., Biswas, C.S., Wang, Q., Liang, W., Stadler, F.J., 2017. Crosslinking hydroxylated reduced graphene oxide with RAFT-CTA: a nano-initiator for preparation of well-defined amino acid-based polymer nanohybrids. J. Colloid Interface Sci. 504, 731–740. Nascimento, V.R.S., Bilal, M., Bharagava, R.N., Iqbal, H.M., Ferreira, L.F.R., Figueiredo, R.T., 2022. Application of TiO2 photocatalysts hybridized with 20 A. Farhan et al. Environmental Pollution 308 - Ranjan, B., Pillai, S., Permaul, K., Singh, S., 2019. Simultaneous removal of heavy metals and cyanate in a wastewater sample using immobilized cyanate hydratase on magnetic-multiwall carbon nanotubes. J. Hazard Mater. 363, 73–80. Rasheed, T., Ahmad, N., Ali, J., Hassan, A.A., Sher, F., Rizwan, K., et al., 2021. Nano and micro architectured cues as smart materials to mitigate recalcitrant pharmaceutical pollutants from wastewater. Chemosphere, 129785. Rasheed, T., Bilal, M., Hassan, A.A., Nabeel, F., Bharagava, R.N., Ferreira, L.F.R., et al., 2020. Environmental threatening concern and efficient removal of pharmaceutically active compounds using metal-organic frameworks as adsorbents. Environ. Res. 185, 109436. Rasheed, T., Rizwan, K., Shafi, S., Bilal, M., 2022. Nanobiodegradation of pharmaceutical pollutants. In: Biodegradation and Biodeterioration at the Nanoscale. Elsevier, pp. 635–653. Rodríguez, C., Tapia, C., Leiva-Aravena, E., Leiva, E., 2020. Graphene oxide–ZnO nanocomposites for removal of aluminum and copper ions from acid mine drainage wastewater. Int. J. Environ. Res. Publ. Health 17 (18), 6911. Rosca, I.D., Watari, F., Uo, M., Akasaka, T., 2005. Oxidation of multiwalled carbon nanotubes by nitric acid. Carbon 43 (15),-. Samuel, M.S., Suman, S., Selvarajan, E., Mathimani, T., Pugazhendhi, A., 2020. Immobilization of Cu3 (btc) 2 on graphene oxide-chitosan hybrid composite for the adsorption and photocatalytic degradation of methylene blue. J. Photochem. Photobiol. B Biol. 204, 111809. Santamaría-Juárez, G., Gómez-Barojas, E., Quiroga-González, E., Sánchez-Mora, E., Quintana-Ruiz, M., Santamaría-Juárez, J.D., 2020. Safer modified Hummers’ method for the synthesis of graphene oxide with high quality and high yield. Mater. Res. Express 6 (12), 125631. Serenari, F., Madinehei, M., Moghimian, N., Fabiani, D., David, E., 2020. Development of reinforced polyester/graphene nanocomposite showing tailored electrical conductivity. Polymers 12 (10), 2358. Shen, H., Wang, J., Jiang, J., Luo, B., Mao, B., Shi, W., 2017. All-solid-state Z-scheme system of RGO-Cu2O/Bi2O3 for tetracycline degradation under visible-light irradiation. Chem. Eng. J. 313, 508–517. Shen, J., Hu, Y., Shi, M., Lu, X., Qin, C., Li, C., Ye, M., 2009. Fast and facile preparation of graphene oxide and reduced graphene oxide nanoplatelets. Chem. Mater. 21 (15),-. Shende, T., Bhanvase, B., Rathod, A., Pinjari, D., Sonawane, S., 2018. Sonochemical synthesis of Graphene-Ce-TiO2 and Graphene-Fe-TiO2 ternary hybrid photocatalyst nanocomposite and its application in degradation of crystal violet dye. Ultrason. Sonochem. 41, 582–589. Shtepliuk, I., Vagin, M., Yakimova, R., 2020. Electrochemical deposition of copper on epitaxial graphene. Appl. Sci. 10 (4), 1405. Shyamala, R., Devi, L.G., 2020. Reduced graphene oxide/SnO2 nanocomposites for the photocatalytic degradation of rhodamine B: preparation, characterization, photosensitization, vectorial charge transfer mechanism and identification of reaction intermediates. Chem. Phys. Lett. 748, 137385. Si, M., Wang, W., Guan, Q., Zhang, H., Puttaswamy, M., 2021. Facile fabrication of highly catalytic-active Ag 2 CO 3/AgBr/graphene oxide ternary composites towards the photocatalytic wastewater treatment. Environ. Sci. Pollut. Control Ser. 28 (4),-. Sinclair, R.C., Suter, J.L., Coveney, P.V., 2019. Micromechanical exfoliation of graphene on the atomistic scale. Phys. Chem. Chem. Phys. 21 (10),-. Singh, P., Shandilya, P., Raizada, P., Sudhaik, A., Rahmani-Sani, A., HosseiniBandegharaei, A., 2020. Review on various strategies for enhancing photocatalytic activity of graphene based nanocomposites for water purification. Arab. J. Chem. 13 (1),-. Singh, V., Joung, D., Zhai, L., Das, S., Khondaker, S.I., Seal, S., 2011. Graphene based materials: past, present and future. Prog. Mater. Sci. 56 (8),-. Sinitskii, A., Dimiev, A., Corley, D.A., Fursina, A.A., Kosynkin, D.V., Tour, J.M., 2010. Kinetics of diazonium functionalization of chemically converted graphene nanoribbons. ACS Nano 4 (4),-. Siwińska-Stefańska, K., Fluder, M., Tylus, W., Jesionowski, T., 2018. Investigation of amino-grafted TiO2/reduced graphene oxide hybrids as a novel photocatalyst used for decomposition of selected organic dyes. J. Environ. Manag. 212, 395–404. Slonczewski, J., Weiss, P., 1958. Band structure of graphite. Phys. Rev. 109 (2), 272. Soltani, T., Tayyebi, A., Lee, B.-K., 2018. Enhanced photoelectrochemical (PEC) and photocatalytic properties of visible-light reduced graphene-oxide/bismuth vanadate. Appl. Surf. Sci. 448, 465–473. Soltani, T., Tayyebi, A., Lee, B.-K., 2019. Photolysis and photocatalysis of tetracycline by sonochemically heterojunctioned BiVO4/reduced graphene oxide under visible-light irradiation. J. Environ. Manag. 232, 713–721. Song, P., Xu, Z., Wu, Y., Cheng, Q., Guo, Q., Wang, H., 2017. Super-tough artificial nacre based on graphene oxide via synergistic interface interactions of π-π stacking and hydrogen bonding. Carbon 111, 807–812. Song, S., Cheng, B., Wu, N., Meng, A., Cao, S., Yu, J., 2016. Structure effect of graphene on the photocatalytic performance of plasmonic Ag/Ag2CO3-rGO for photocatalytic elimination of pollutants. Appl. Catal. B Environ. 181, 71–78. Song, S., Wang, K., Zhang, Y., Wang, Y., Zhang, C., Wang, X., Wang, X., 2019. Selfassembly of graphene oxide/PEDOT: PSS nanocomposite as a novel adsorbent for uranium immobilization from wastewater. Environ. Pollut. 250, 196–205. Stoller, M.D., Park, S., Zhu, Y., An, J., Ruoff, R.S., 2008. Graphene-based ultracapacitors. Nano Lett. 8 (10),-. Su, X., Yang, J., Yu, X., Zhu, Y., Zhang, Y., 2018. In situ grown hierarchical 50% BiOCl/ BiOI hollow flowerlike microspheres on reduced graphene oxide nanosheets for enhanced visible-light photocatalytic degradation of rhodamine B. Appl. Surf. Sci. 433, 502–512. carbonaceous for degradation of pharmaceuticals. In: Development in Wastewater Treatment Research and Processes. Elsevier, pp. 323–348. Nawaz, A., Khan, A., Ali, N., Mao, P., Gao, X., Ali, N., et al., 2022. Synthesis of ternarybased visible light nano-photocatalyst for decontamination of organic dyes-loaded wastewater. Chemosphere 289, 133121. Nasibulin, A.G., Pikhitsa, P.V., Jiang, H., Brown, D.P., Krasheninnikov, A.V., Anisimov, A.S., Lientschnig, G., 2007. A novel hybrid carbon material. Nat. Nanotechnol. 2 (3), 156–161. Nguyen, C.H., Juang, R.-S., 2019. Efficient removal of methylene blue dye by a hybrid adsorption–photocatalysis process using reduced graphene oxide/titanate nanotube composites for water reuse. J. Ind. Eng. Chem. 76, 296–309. Nguyen, D.C.T., Cho, K.-Y., Oh, W.-C., 2017. Synthesis of frost-like CuO combined graphene-TiO2 by self-assembly method and its high photocatalytic performance. Appl. Surf. Sci. 412, 252–261. Noreen, S., Perveen, S., Shafiq, N., Aslam, S., Iqbal, H.M., Ashraf, S.S., Bilal, M., 2021. Laccase-loaded functionalized graphene oxide assemblies with improved biocatalytic properties and decolorization performance. Environ. Technol. Innovat. 24, 101884. Novoselov, K.S., Geim, A.K., Morozov, S.V., Jiang, D.-e., Zhang, Y., Dubonos, S.V., Firsov, A.A., 2004. Electric field effect in atomically thin carbon films. Science 306 (5696), 666–669. Novoselov, K.S., Geim, A.K., Morozov, S.V., Jiang, D., Katsnelson, M.I., Grigorieva, I., Firsov, a., 2005. Two-dimensional gas of massless Dirac fermions in graphene. Nature 438 (7065), 197–200. Novoselov, K.S., Jiang, Z., Zhang, Y., Morozov, S., Stormer, H.L., Zeitler, U., Geim, A.K., 2007. Room-temperature quantum Hall effect in graphene. Science 315 (5817), 1379, 1379. Omrani, E., Moghadam, A.D., Algazzar, M., Menezes, P.L., Rohatgi, P.K., 2016. Effect of graphite particles on improving tribological properties Al-16Si-5Ni-5Graphite selflubricating composite under fully flooded and starved lubrication conditions for transportation applications. Int. J. Adv. Manuf. Technol. 87 (1), 929–939. Ong, C.B., Ng, L.Y., Mohammad, A.W., 2018. A review of ZnO nanoparticles as solar photocatalysts: synthesis, mechanisms and applications. Renew. Sustain. Energy Rev. 81, 536–551. OuYang, F., Huang, B., Li, Z., Xiao, J., Wang, H., Xu, H., 2008. Chemical functionalization of graphene nanoribbons by carboxyl groups on stone-wales defects. J. Phys. Chem. C 112 (31),-. Ouyang, W., Sun, J., Memon, J., Wang, C., Geng, J., Huang, Y., 2013. Scalable preparation of three-dimensional porous structures of reduced graphene oxide/ cellulose composites and their application in supercapacitors. Carbon 62, 501–509. Öztop, B., Gürbüz, M., 2017. Investigation of properties of composites produced by reinforcement graphene matrix obtained from waste aluminium. Int. J. Multidiscipl. Stud. Innov. Technol. 1 (1), 4–8. Padmajan Sasikala, S., Poulin, P., Aymonier, C., 2016. Prospects of supercritical fluids in realizing graphene-based functional materials. Adv. Mater. 28 (14),-. Pan, L., Wang, Z., Yang, Q., Huang, R., 2018. Efficient removal of lead, copper and cadmium ions from water by a porous calcium alginate/graphene oxide composite aerogel. Nanomaterials 8 (11), 957. Park, S., An, J., Potts, J.R., Velamakanni, A., Murali, S., Ruoff, R.S., 2011. Hydrazinereduction of graphite-and graphene oxide. Carbon 49 (9),-. Park, S., Lee, K.-S., Bozoklu, G., Cai, W., Nguyen, S.T., Ruoff, R.S., 2008. Graphene oxide papers modified by divalent ions—enhancing mechanical properties via chemical cross-linking. ACS Nano 2 (3), 572–578. Parker, C.B., Raut, A.S., Brown, B., Stoner, B.R., Glass, J.T., 2012. Three-dimensional arrays of graphenated carbon nanotubes. J. Mater. Res. 27 (7),-. Patil, A.J., Vickery, J.L., Scott, T.B., Mann, S., 2009. Aqueous stabilization and selfassembly of graphene sheets into layered bio-nanocomposites using DNA. Adv. Mater. 21 (31),-. Peer, F.E., Bahramifar, N., Younesi, H., 2018. Removal of Cd (II), Pb (II) and Cu (II) ions from aqueous solution by polyamidoamine dendrimer grafted magnetic graphene oxide nanosheets. J. Taiwan Inst. Chem. Eng. 87, 225–240. Peng, Y., Ji, J., Chen, D., 2015. Ultrasound assisted synthesis of ZnO/reduced graphene oxide composites with enhanced photocatalytic activity and anti-photocorrosion. Appl. Surf. Sci. 356, 762–768. Pethsangave, D.A., Khose, R.V., Wadekar, P.H., Some, S., 2019. Novel approach toward the synthesis of a phosphorus-functionalized polymer-based graphene composite as an efficient flame retardant. ACS Sustain. Chem. Eng. 7 (13),-. Phan, T.D., Vo, C.M., Tran, T.M.T., Luu, T.L.A., Nguyen, X.S., 2019. Structural and bandgap properties of titanium dioxide nanotube/graphene oxide composites prepared by a facile hydrothermal method. Mater. Res. Express 6 (10), 105054. Pingale, A.D., Belgamwar, S.U., Rathore, J.S., 2020. The influence of graphene nanoplatelets (GNPs) addition on the microstructure and mechanical properties of Cu-GNPs composites fabricated by electro-co-deposition and powder metallurgy. Mater. Today Proc. 28,-. Platnieks, O., Gaidukovs, S., Neibolts, N., Barkane, A., Gaidukova, G., Thakur, V., 2020. Poly (butylene succinate) and graphene nanoplatelet–based sustainable functional nanocomposite materials: structure-properties relationship. Mater. Today Chem. 18, 100351. Pu, S., Zhu, R., Ma, H., Deng, D., Pei, X., Qi, F., Chu, W., 2017. Facile in-situ design strategy to disperse TiO2 nanoparticles on graphene for the enhanced photocatalytic degradation of rhodamine 6G. Appl. Catal. B Environ. 218, 208–219. Rameshbabu, R., Vinoth, R., Navaneethan, M., Harish, S., Hayakawa, Y., Neppolian, B., 2017. Visible light responsive Cu2MoS4 nanosheets incorporated reduced graphene oxide for efficient degradation of organic pollutant. Appl. Surf. Sci. 418, 128–137. 21 A. Farhan et al. Environmental Pollution 308 - Tang, B., Chen, H., Peng, H., Wang, Z., Huang, W., 2018. Graphene modified TiO2 composite photocatalysts: mechanism, progress and perspective. Nanomaterials 8 (2), 105. Tang, H., Ehlert, G.J., Lin, Y., Sodano, H.A., 2012. Highly efficient synthesis of graphene nanocomposites. Nano Lett. 12 (1), 84–90. Tang, L., Jia, C.-t., Xue, Y.-c., Li, L., Wang, A.-q., Xu, G., Wu, M.-h., 2017. Fabrication of compressible and recyclable macroscopic g-C3N4/GO aerogel hybrids for visiblelight harvesting: a promising strategy for water remediation. Appl. Catal. B Environ. 219, 241–248. Tapasztó, O., Tapasztó, L., Lemmel, H., Puchy, V., Dusza, J., Balázsi, C., Balázsi, K., 2016. High orientation degree of graphene nanoplatelets in silicon nitride composites prepared by spark plasma sintering. Ceram. Int. 42 (1),-. Tarcan, R., Todor-Boer, O., Petrovai, I., Leordean, C., Astilean, S., Botiz, I., 2020. Reduced graphene oxide today. J. Mater. Chem. C 8 (4),-. Teow, Y.H., Mohammad, A.W., 2019. New generation nanomaterials for water desalination: a review. Desalination 451, 2–17. Terzopoulou, Z., Kyzas, G.Z., Bikiaris, D.N., 2015. Recent advances in nanocomposite materials of graphene derivatives with polysaccharides. Materials 8 (2), 652–683. Tong, Z., Yang, D., Shi, J., Nan, Y., Sun, Y., Jiang, Z., 2015. Three-dimensional porous aerogel constructed by g-C3N4 and graphene oxide nanosheets with excellent visible-light photocatalytic performance. ACS Appl. Mater. Interfaces 7 (46),-. Varshney, D., Venkateswara Rao, C., Guinel, M.J.-F., Ishikawa, Y., Weiner, B.R., Morell, G., 2011. Free standing graphene-diamond hybrid films and their electron emission properties. J. Appl. Phys. 110 (4), 044324. Velasco-Hernández, A., Esparza-Muñoz, R., de Moure-Flores, F., Santos-Cruz, J., MayénHernández, S., 2020. Synthesis and characterization of graphene oxide-TiO2 thin films by sol-gel for photocatalytic applications. Mater. Sci. Semicond. Process. 114, 105082. Venturi, F., Pulsford, J., Hussain, T., 2020. A novel approach to incorporate graphene nanoplatelets to Cr2O3 for low-wear coatings. Mater. Lett. 276, 128283. Vinodhkumar, G., Wilson, J., Inbanathan, S., Potheher, I.V., Ashokkumar, M., Peter, A.C., 2020. Solvothermal synthesis of magnetically separable reduced graphene oxide/ Fe3O4 hybrid nanocomposites with enhanced photocatalytic properties. Phys. B Condens. Matter 580, 411752. Wan, Y., Liang, C., Xia, Y., Huang, W., Li, Z., 2017. Fabrication of graphene oxide enwrapped Z-scheme Ag2SO3/AgBr nanoparticles with enhanced visible-light photocatalysis. Appl. Surf. Sci. 396, 48–57. Wang, C.-I., Periasamy, A.P., Chang, H.-T., 2013. Photoluminescent C-dots@ RGO probe for sensitive and selective detection of acetylcholine. Anal. Chem. 85 (6),-. Wang, J., Gao, Z., Li, Z., Wang, B., Yan, Y., Liu, Q., Jiang, Z., 2011a. Green synthesis of graphene nanosheets/ZnO composites and electrochemical properties. J. Solid State Chem. 184 (6),-. Wang, Q., Cui, X., Chen, J., Zheng, X., Liu, C., Xue, T., Zheng, W., 2012. Well-dispersed palladium nanoparticles on graphene oxide as a non-enzymatic glucose sensor. RSC Adv. 2 (15),-. Wang, S., Cai, J., Mao, J., Li, S., Shen, J., Gao, S., Lai, Y., 2019a. Defective black Ti3+ self-doped TiO2 and reduced graphene oxide composite nanoparticles for boosting visible-light driven photocatalytic and photoelectrochemical activity. Appl. Surf. Sci. 467, 45–55. Wang, T., Meng, Q., Araby, S., Yang, G., Li, P., Cai, R., Wang, W., 2021a. Non-oxidized graphene/metal composites by laser deposition additive manufacturing. J. Alloys Compd., 160724 Wang, T., Tang, T., Gao, Y., Chen, Q., Zhang, Z., Bian, H., 2019b. Hydrothermal preparation of Ag-TiO2-reduced graphene oxide ternary microspheres structure composite for enhancing photocatalytic activity. Phys. E Low-dimens. Syst. Nanostruct. 112, 128–136. Wang, X., Shi, G., 2015. An introduction to the chemistry of graphene. Phys. Chem. Chem. Phys. 17 (43),-. Wang, X., Xu, P., Zhang, P., Ma, S., 2021b. Preparation of electrode materials based on carbon cloth via hydrothermal method and their application in supercapacitors. Materials 14 (23), 7148. Wang, X., Zhao, J., Cui, E., Tian, X., Sun, Z., 2021c. Effect of interfacial structure on mechanical properties of graphene reinforced Al2O3–WC matrix ceramic composite. Nanomaterials 11 (6), 1374. Wang, Y., Zhang, S., Du, D., Shao, Y., Li, Z., Wang, J., Lin, Y., 2011b. Self assembly of acetylcholinesterase on a gold nanoparticles–graphene nanosheet hybrid for organophosphate pesticide detection using polyelectrolyte as a linker. J. Mater. Chem. 21 (14),-. Wang, Z., Wang, Y., Huang, L., Liu, X., Han, Y., Wang, L., 2020. La2Zr2O7/rGO synthesized by one-step sol-gel method for photocatalytic degradation of tetracycline under visible-light. Chem. Eng. J. 384, 123380. Wei, D., Liu, Y., Wang, Y., Zhang, H., Huang, L., Yu, G., 2009. Synthesis of N-doped graphene by chemical vapor deposition and its electrical properties. Nano Lett. 9 (5),-. Wei, Z., Wang, D., Kim, S., Kim, S.-Y., Hu, Y., Yakes, M.K., Berger, C., 2010. Nanoscale tunable reduction of graphene oxide for graphene electronics. Science 328 (5984),-. Wen, T., Wu, X., Tan, X., Wang, X., Xu, A., 2013. One-pot synthesis of water-swellable Mg–Al layered double hydroxides and graphene oxide nanocomposites for efficient removal of as (V) from aqueous solutions. ACS Appl. Mater. Interfaces 5 (8),-. Wu, F., Duan, W., Li, M., Xu, H., 2018a. Synthesis of MgFe2O4/reduced graphene oxide composite and its visible-light photocatalytic performance for organic pollution. Int. J. Photoenergy 2018. Wu, J., Wang, J., Huang, X., Bai, H., 2018b. A self-assembly route to porous polyaniline/ reduced graphene oxide composite materials with molecular-level uniformity for high-performance supercapacitors. Energy Environ. Sci. 11 (5),-. Wu, J., Zhao, H., Chen, R., Pham-Huy, C., Hui, X., He, H., 2016. Adsorptive removal of trace sulfonamide antibiotics by water-dispersible magnetic reduced graphene oxide-ferrite hybrids from wastewater. J. Chromatogr. B 1029, 106–112. Wu, T., Liu, S., Li, H., Wang, L., Sun, X., 2011. Production of reduced graphene oxide by UV irradiation. J. Nanosci. Nanotechnol. 11 (11),-. Wu, Z., Deng, W., Zhou, W., Luo, J., 2019. Novel magnetic polysaccharide/graphene oxide@ Fe3O4 gel beads for adsorbing heavy metal ions. Carbohydr. Polym. 216, 119–128. Xia, Z., Leonardi, F., Gobbi, M., Liu, Y., Bellani, V., Liscio, A., Orgiu, E., 2016. Electrochemical functionalization of graphene at the nanoscale with self-assembling diazonium salts. ACS Nano 10 (7),-. Xiao, P., Jiang, D., Ju, L., Jing, J., Chen, M., 2018. Construction of RGO/CdIn2S4/gC3N4 ternary hybrid with enhanced photocatalytic activity for the degradation of tetracycline hydrochloride. Appl. Surf. Sci. 433, 388–397. Xiong, C., Li, B., Duan, C., Dai, L., Nie, S., Qin, C., Ni, Y., 2021. Carbonized wood cell chamber-reduced graphene oxide@ PVA flexible conductive material for supercapacitor, strain sensing and moisture-electric generation applications. Chem. Eng. J. 418, 129518. Xiong, Y., Xie, Y., Zhang, F., Ou, E., Jiang, Z., Ke, L., Xu, W., 2012. Reduced graphene oxide/hydroxylated styrene–butadiene–styrene tri-block copolymer electroconductive nanocomposites: preparation and properties. Mater. Sci. Eng., B 177 (14),-. Xu, L., Wei, Y., Guo, W., Guo, Y., Guo, Y., 2015. One-pot solvothermal preparation and enhanced photocatalytic activity of metallic silver and graphene co-doped BiVO4 ternary systems. Appl. Surf. Sci. 332, 682–693. Xu, L., Yang, L., Johansson, E.M., Wang, Y., Jin, P., 2018. Photocatalytic activity and mechanism of bisphenol a removal over TiO2− x/rGO nanocomposite driven by visible light. Chem. Eng. J. 350,-. Yang, L., Li, Z., Jiang, H., Jiang, W., Su, R., Luo, S., Luo, Y., 2016. Photoelectrocatalytic oxidation of bisphenol A over mesh of TiO2/graphene/Cu2O. Appl. Catal. B Environ. 183, 75–85. Yang, R., Zhong, S., Zhang, L., Liu, B., 2020. PW12/CN@ Bi2WO6 composite photocatalyst prepared based on organic-inorganic hybrid system for removing pollutants in water. Separ. Purif. Technol. 235, 116270. Yang, W., Zhang, L., Guo, Y., Jiang, Z., He, F., Xie, C., Zhang, K., 2018a. Novel segregated-structure phase change materials composed of paraffin@ graphene microencapsules with high latent heat and thermal conductivity. J. Mater. Sci. 53 (4),-. Yang, X., Ma, L., Wang, S., Li, Y., Tu, Y., Zhu, X., 2011. Clicking” graphite oxide sheets with well-defined polystyrenes: a new strategy to control the layer thickness. Polymer 52 (14),-. Yang, X., Zhou, T., Ren, B., Hursthouse, A., Zhang, Y., 2018b. Removal of Mn (II) by sodium alginate/graphene oxide composite double-network hydrogel beads from aqueous solutions. Sci. Rep. 8 (1), 1–16. Yao, B., Li, C., Ma, J., Shi, G., 2015. Porphyrin-based graphene oxide frameworks with ultra-large d-spacings for the electrocatalyzation of oxygen reduction reaction. Phys. Chem. Chem. Phys. 17 (29),-. Yao, M., Wang, Z., Liu, Y., Yang, G., Chen, J., 2019. Preparation of dialdehyde cellulose graftead graphene oxide composite and its adsorption behavior for heavy metals from aqueous solution. Carbohydr. Polym. 212, 345–351. Yi, J., Lee, J.M., Park, W.I., 2011. Vertically aligned ZnO nanorods and graphene hybrid architectures for high-sensitive flexible gas sensors. Sensor. Actuator. B Chem. 155 (1), 264–269. Yılmaz, E., Çakıroğlu, B., Gökçe, A., Findik, F., Gulsoy, H.O., Gulsoy, N., Özacar, M., 2019. Novel hydroxyapatite/graphene oxide/collagen bioactive composite coating on Ti16Nb alloys by electrodeposition. Mater. Sci. Eng. C 101, 292–305. Yin, Z., Cui, C., Chen, H., Yu, X., Qian, W., 2020. The application of carbon nanotube/ graphene-based nanomaterials in wastewater treatment. Small 16 (15),-. Yu, L., Zhang, Y., Zhang, B., Liu, J., Zhang, H., Song, C., 2013. Preparation and characterization of HPEI-GO/PES ultrafiltration membrane with antifouling and antibacterial properties. J. Membr. Sci. 447, 452–462. Yu, W., Sisi, L., Haiyan, Y., Jie, L., 2020a. Progress in the functional modification of graphene/graphene oxide: a review. RSC Adv. 10 (26),-. Yu, W., Zhang, X., Gao, X., Liu, H., Zhang, X., 2020b. Fabrication of high-strength PET fibers modified with graphene oxide of varying lateral size. J. Mater. Sci. 55 (21),-. Yun, S., Kim, J., 2009. Covalently bonded multi-walled carbon nanotubes-cellulose electro-active paper actuator. Sensor Actuator Phys. 154 (1), 73–78. Zhang, C., Huang, S., Tjiu, W.W., Fan, W., Liu, T., 2012. Facile preparation of waterdispersible graphene sheets stabilized by acid-treated multi-walled carbon nanotubes and their poly (vinyl alcohol) composites. J. Mater. Chem. 22 (6),-. Zhang, H., Guo, L.-H., Wang, D., Zhao, L., Wan, B., 2015. Light-induced efficient molecular oxygen activation on a Cu (II)-grafted TiO2/graphene photocatalyst for phenol degradation. ACS Appl. Mater. Interfaces 7 (3),-. Zhang, L.L., Zhou, R., Zhao, X., 2010. Graphene-based materials as supercapacitor electrodes. J. Mater. Chem. 20 (29),-. Zhang, Y., Tan, Y.-W., Stormer, H.L., Kim, P., 2005. Experimental observation of the quantum Hall effect and Berry’s phase in graphene. Nature 438 (7065), 201–204. Zhao, B., Zhang, X., Deng, J., Zhang, C., Li, Y., Guo, X., Zhang, R., 2020. Flexible PEBAX/ graphene electromagnetic shielding composite films with a negative pressure effect of resistance for pressure sensors applications. RSC Adv. 10 (3),-. 22 A. Farhan et al. Environmental Pollution 308 - Zhao, Y., Liu, L., Cui, T., Tong, G., Wu, W., 2017. Enhanced photocatalytic properties of ZnO/reduced graphene oxide sheets (rGO) composites with controllable morphology and composition. Appl. Surf. Sci. 412, 58–68. Zhao, Y., Yu, W., Li, R., Xu, Y., Liu, Y., Sun, T., Lin, H., 2019. Electric field endowing the conductive polyvinylidene fluoride (PVDF)-graphene oxide (GO)-nickel (Ni) membrane with high-efficient performance for dye wastewater treatment. Appl. Surf. Sci. 483,-. Zhou, W.-L., Chen, Y., Yu, Q., Zhang, H., Liu, Z.-X., Dai, X.-Y., Liu, Y., 2020. Ultralong purely organic aqueous phosphorescence supramolecular polymer for targeted tumor cell imaging. Nat. Commun. 11 (1), 1–10. Zhou, Y., Fang, Y., Ramasamy, R.P., 2019. Non-covalent functionalization of carbon nanotubes for electrochemical biosensor development. Sensors 19 (2), 392. Zhu, J., Zhu, Z., Zhang, H., Lu, H., Zhang, W., Qiu, Y., Küppers, S., 2018. Calcined layered double hydroxides/reduced graphene oxide composites with improved photocatalytic degradation of paracetamol and efficient oxidation-adsorption of as (III). Appl. Catal. B Environ. 225, 550–562. Zhu, W., Jiang, X., Liu, F., You, F., Yao, C., 2020. Preparation of chitosan—graphene oxide composite aerogel by hydrothermal method and its adsorption property of methyl orange. Polymers 12 (9), 2169. 23