GO Sheets Research Articles

Combination of MoS2 nanopetals with Ag nanoparticles decorated graphene oxide for boosting photocatalytic abatement of recalcitrant pollutants under visible light irradiation

Herein, various weight ratios (1:1, 1:3, and 3:1) of MoS2/GO composites decorated with Ag nanoparticles (named as MAG) have been prepared by microwave-assisted route. XRD and XPS investigations indicated the catalyst crystallinity and elemental oxidation states. Morphological analysis revealed presence of small MoS2 nanopetals scattered on GO sheets with Ag NPs dispersed on surface whereas BET-analysis disclosed its excellent surface area (∼88 m2/g). Optical properties of MAG catalysts revealed that they were highly visible-light active, with a bandgap of 2.15 eV and a lower charge recombination rate. Excellent efficiency was observed for TC (90.7%; 0.0186 min−1) and FIP-degradation (85.2%; 0.0177 min−1) with 4 mg MAG (3:1) catalyst at neutral pH under visible-light irradiation owing to high synergistic interaction (∼2.21) in the composite. Effects of catalyst amount, pH, and effective area of illumination on degradation were investigated. High reusable nature of the catalyst (65% (TC) and 58% (FIP) efficiency after 5 cycles) was supported by post-photocatalytic characterization studies. Photodegradation products of TC were determined via LC-MS studies. Holes and hydroxyl radicals were majorly involved in degradation process revealed by trapping studies. High COD (70.4%) and TOC (55.1%) removal rates confirm high photo-mineralization of real-wastewater without any pre-treatment. The current investigation, combined with comparative literature, illustrates real-world potential of MAG catalysts for eradication of resistant pollutants.

Novel green synthesis of graphene oxide-manganese dioxide using solution plasma process for energy storage

Graphene oxide-manganese dioxide (GO-MnO2) forms an interesting family of nanocomposites that have been widely studied and applied to many electrochemical applications, including supercapacitors. However, a number of reported preparation methods still suffer several disadvantages, including complex preparation, long synthesis time, and detrimental effects on the environment as a result of excessive use of chemicals. In contrast, solution plasma process (SPP) offers a simple method that can be used to synthesize nanomaterials with minimal use of chemical reagents and short preparation time under ambient processing conditions. This work demonstrated that SPP-based preparation of the GO-MnO2 composite can be achieved. Moreover, the SPP regime was found to enable interaction between the Mn ions and the exfoliated GO sheets, with the capability of upscaling the preparation. The highest specific capacitance of the GO-MnO2 composite was obtained when only 10 min of SPP discharge time was used, resulting in the specific capacitance of 218 F g−1 at a scan rate of 5 mV s−1 in 1 M Na2SO4 aqueous electrolyte solution. This method provides a facile in situ approach to deposit MnO2 onto the GO sheets and could offer a promising, green alternative strategy to prepare similar electrode materials for other applications.

Study on the strengthening and toughening design of the interlayer interface of GO-based bionic nacre composites and its optimization mechanisms

Inspired by the mineral bridge between hard phase layers of natural nacre, this paper investigates the mechanical properties and optimization strategies of GO-based bionic “brick-mortar” structural composites with interface modification by CNTs. After selectively combining CNTs with GO sheets of different sizes, four biomimetic composites with the same structure but different distributions of strong, medium and weak interfaces were obtained. A comparative study on the mechanical property tests and the finite element simulation results of the samples revealed that the difference in the distributions of different strength interfaces within the material/structure have a significant impact on their localized interfacial failures and subsequent crack extensions, making the deflection of cracks more inclined along the weak interface. Further analysis showed that the targeted and focused optimization of dangerous interfaces with low interfacial bond strength and high stress levels within the material is an effective way to improve the mechanical properties of bionic “brick-mortar” structural composites. The results of the above study will provide useful guidance for the interface optimization and lightweight strengthening and toughness design of composites.

Graphene oxide enhances thermal stability and microwave absorption/regeneration of a porous polymer

Microwave regeneration of adsorbents offers several advantages over conventional regeneration methods; however, its application for microwave transparent adsorbents such as polymers is challenging. In this study, hypercrosslinked polymer/graphene oxide (GO) nanocomposites with large surface area and enhanced microwave absorption ability were synthesized. Polymers of 4, 4´-bis ((chloromethyl)-1, 1´-biphenyl- benzyl chloride) were hypercrosslinked through the Friedel-Crafts reactions. GO sheets were synthesized through the Hummer’s method. Nanocomposites with different GO contents (1–8 wt%) were synthesized by solution mixing method. Thermogravimetry analysis revealed a large enhancement in the thermal stability of GO-filled nanocomposites compared to pristine polymer. N2 adsorption isotherm analysis showed 7% and 10% reduction in BET surface area and total pore volume of the nanocomposite with 8 wt% GO. Compared to the pristine polymer, the dielectric constant and dielectric loss factor increased from 5 to 17 and 0.05–1.6, respectively, for the nanocomposites with 8 wt% GO. Microwave-assisted desorption of toluene from samples revealed more than 160 ºC and 4 times improvement in the desorption temperature and desorption efficiency, respectively, by addition of 4 wt% GO to the polymer. This study showed the important role of GO addition for efficient microwave-assisted regeneration of polymer adsorbents.

Magnetically separable Fe3O4/graphene oxide nanocomposite: An efficient heterogenous catalyst for spirooxindole derivatives synthesis

Heterocyclic compounds such as spirooxindole, with five rings containing nitrogen, have an important role in the realm of medicine. This study aims to synthesize the spirooxindole derivative compounds using Fe3O4/graphene oxide (GO) nanocomposite as the catalyst. The GO sample was synthesized by Hummers' method, followed by the insertion of Fe3O4 into the graphene oxide layers by the co-precipitation method. Both XRD and FTIR analyses reveal that GO and Fe3O4/GO samples have been successfully formed. SEM-EDX micrograph supported by TEM image indicates that the Fe3O4 nanoparticles in the composite have excellent dispersibility, attributable to the existence of the GO sheets. The evaluation of the ability of Fe3O4/GO as a catalyst in the synthesis of spirooxindole derivatives was carried out by the one-pot three-component method. The reaction yield shows that Fe3O4/GO was a suitable and reusable catalyst in this reaction.

Reduced graphene oxide-Mn3O4 composites as effective electron acceptors for hybrid polymer-based solar cells

In this work, reduced graphene oxide (rGO)-Mn3O4 composites with different weight ratios were prepared by solvothermal method. The Mn3O4 nanoparticles were distributed on the rGO sheets in a monodispersed state and at the same time GO sheets were reduced to rGO sheets. Furthermore, rGO-Mn3O4 composites were employed as electron acceptors for hybrid polymer-based solar cells. The distribution of Mn3O4 nanoparticles on graphene sheets imposes a remarkable effect on device performance. It is demonstrated that the hybrid polymer-based solar cells based on blend of poly(1-methoxy-4-(2-ethylhexyloxy)-p-phenylene vinylene) and rGO-Mn3O4 composite with weight ration of rGO/Mn3O4 (1:1) exhibited a peak power conversion efficiency of 1.04%, which was 5-fold higher than that of the counterpart devices of MEH-PPV/rGO sheets.

Water-Based Graphene Oxide-Silicon Hybrid Nanofluids-Experimental and Theoretical Approach.

In the current paper, a new hybrid nanofluid based on graphene oxide sheets and silicon nanoparticles is proposed for thermal applications. GO sheets and Si nanoparticles with different mixture ratios are dispersed in distilled water. Dynamic viscosity is measured at temperatures within the range 20–50 °C and the values are compared to the results available in the literature. The results indicated that the viscosity increases with increasing the mixture ratio of graphene oxide. A new correlation for the dynamic viscosity based on the experimental findings is proposed. Finally, the criteria for the performance of new hybrid nanofluid for thermal applications are analyzed.

Phosphonium-defoliated GO nanosheets as micropore booster of carbon membrane to improve separation of tetracycline from isopropanol

This study developed a supported carbon membrane (CM) to conduct organic solvent nanofiltration (OSN). The OSN performance was tuned up by dispersing phosphonium-defoliated graphene oxide (PGO) as filler (0.3 wt%) in the precursor (bitumen) coating. PGO was synthesized through anchoring phosphonium (Ph3PBu+) ions to the oxygenated groups dangled on individual GO sheets that take up 49 wt% of PGO. As PGO experiences elimination of the pendant organic functional groups to form a graphene-like sheet through the course of pyrolysis and carbonization that converts the precursor coating to CM, the graphene-like sheets thus act to induce in-situ face-to-face stacking of the planar polyaromatic hydrocarbons (PAHs) generated from the pyrolysis of bitumen in nanoscale. PGO achieved a superior efficacy of induction than GO because of the defoliating role of phosphonium ion that assures a higher dispersity of graphene-like sheets in the precursor coating. This mechanism in the end casts a higher pore volume in membrane CMPGO than in CMGO (600 vs. 334 μl/g) primarily associating with the micro and meso pores inside the carbonaceous grains (~15–20 nm) that constitute the membrane. These tiny pores connect with the grain boundaries (3–5 nm) to form a porous network in the membrane. Moreover, the resultant membrane operates through a dual interaction model of adsorption and size screening. Membrane CMPGO manifests 99.2~94.2% retention of tetracycline (TC) from the permeate (isopropanol) with an average permeance of 32 L/m2·h·bar over 30 h, whereas the control, CMGO, shows progressive declining from 82% to 30% in 10 h. CMPGO was also evaluated by using the oppositely-charged dyes of different sizes to examine the effect of solute identity on percolation.

Silver metal organic frameworks and copper metal organic frameworks immobilized on graphene oxide for enhanced adsorption in water treatment

In this study, copper metal organic frameworks (Cu-MOF) and silver metal organic frameworks (Ag-MOF) were synthesized and immobilized on and between GO sheets using an ultrasonication process. The GO-immobilized MOFs (GO-Ag-MOF and GO-Cu-MOF) showed enhanced physicochemical properties, including enhanced surface area, surface charge, and active adsorption sites confirmed with characterization techniques such as zeta potential, Brunauer–Emmett–Teller (BET), X-ray diffraction (XRD) and scanning electron microscopy (SEM). In addition, the adsorption capacities of Ag-MOF, Cu-MOF, GO-Ag-MOF, and GO-Cu-MOF materials for methylene blue dye (MB), as an organic contaminant model, were thoroughly evaluated at different experimental conditions (pH (3–10), temperature (25–45 °C), and adsorbate concentrations (0–150 ppm)). The kinetics and thermodynamic behavior of the synthesized MOFs revealed that both GO-Ag-MOF and GO-Cu-MOF showed around 10% increase in adsorption capacity in comparison to the pristine Ag-MOF and Cu-MOF at all the tested conditions. GO-Ag-MOF exhibited more than 98 % dye removal, followed by Ag-MOF (90%), GO-Cu-MOF (75%), and Cu-MOF (65%). The main mechanism for adsorption was monolayer adsorption based on electrostatic interactions. All MOFs showed more than 80% re-generability after three regeneration cycles

CaMoO4 Nanoparticle-Doped Graphene Oxide as Electrodes for High-Performance Supercapacitors

CaMoO4 nanoparticles/graphene oxide (CaMoO4/GO) composites are prepared by a facile hydrothermal method. CaMoO4 nanoparticles are adsorbed on the GO sheets by in situ reduction. Along with the synergistic effect between the CaMoO4 and GO sheets, the CaMoO4/GO nanocomposites exhibited high performances as electrodes for supercapacitors. The specific capacity ([Formula: see text] of the CaMoO4/GO electrodes could be up to 571.82[Formula: see text]F[Formula: see text][Formula: see text][Formula: see text]g[Formula: see text] at 0.5[Formula: see text]A[Formula: see text][Formula: see text][Formula: see text]g[Formula: see text]. Furthermore, asymmetric supercapacitors (ASCs) are mainly composed of CaMoO4/GO composite and activated carbon (AC), respectively. The fabricated CaMoO4/GO//AC devices display an energy density of 25.18[Formula: see text]W[Formula: see text][Formula: see text][Formula: see text]h[Formula: see text][Formula: see text][Formula: see text]kg[Formula: see text] at 1710.3[Formula: see text]W[Formula: see text][Formula: see text][Formula: see text]kg[Formula: see text]. A blue LED is powered using two series-connected two ASC devices. These results indicate the considerable potential of CaMoO4/GO for use in high-performance energy storage devices.

Graphene Oxide/Activated Clay/Gelatin Composites: Synthesis, Characterization and Properties

In this work, graphene oxide/activated clay/Gelatin (GO/AC/G) composite blends were prepared by a simple solution mixing method. X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy were investigated to study the novelty in the structural characterization of the samples. The thermal stability was pursued by thermogravimetric analysis (TGA).The obtained results showed a homogeneous mixture was able to be formed between AC, GO, and G. XRD indicated a successful intercalated structure was created in the composites. The disappearance of montmorillonite and GO peaks at 2 = 8.1° and at 2 =13.5° respectively was observed, indicating the homogenous distribution of GO sheets onto activated clay structure. The interlayer spacing increased from 19.4 to 23.5 A due to the insertion of gelatin molecules into the sheets of clay.The IR spectrum of (GO/AC/G) composite revealed the presence of C-O-C bonds, C=C bending, C-OH vibration, and C=O bending. These results suggested that GO had been composited with AC structure. Further, an intense band of N-H at 3419 cm-1 of gelatin was ameliorated through combination with absorption bonds of O-H, indicating the interaction of gelatin with the clay.A comparison of the thermograms of GO/AC and GO/AC/G showed that the thermal stability had been improved.

Sensitive electrochemical sensor based on gold nanoparticles assembled ferrocene-functionalised graphene oxide modified glassy carbon electrode for simultaneous determination of dopamine and acetaminophen

In this article, a novel electron transfer mediator based on the ferrocene-functionalised graphene oxide (Fc-GO) was successfully synthesised by the amide linkage between amino (–NH2) in m-ferrocenylaniline (FcAni) and carboxylic (–COOH) in GO sheet through coupling reagents. This novel electroactive Fc-GO can effectively prevent the ferrocene mediator leaking from the electrode surface. Then, gold nanoparticles assembled ferrocene-functionalised graphene oxide (AuNPs@Fc-GO) was prepared and further confirmed by transmission electron microscopy (TEM), field emission scanning electron microscopy (FE-SEM) with energy dispersive X-ray spectroscopy (EDS), Fourier transform-infrared spectroscopy (FTIR) and X-ray powder diffractometer (XRD). The AuNPs@Fc-GO was modified on the surface of glassy carbon electrode (GCE) to construct an electrochemical sensor for sensitively simultaneous determination of dopamine (DA) and acetaminophen (AC). The characteristics toward DA and AC were investigated by the cyclic voltammetry (CV) and differential pulse voltammetry (DPV) methods. Simultaneous determination of both analytes was accomplished under the optimum condition. The oxidation peak potential of DA and AC was 0.20 and 0.43 V, respectively. The linear current response was obtained in the concentration range of 2–200 μM with the detection limit (S/N = 3) of 0.32 μM for DA and 2–200 μM with the detection limit of 0.21 μM for AC, respectively. Finally, the AuNPs@Fc-GO modified GCE was applied for the determination of DA and AC in human urine samples with satisfactory results. Therefore, the AuNPs@Fc-GO was a novel promising candidate for fabricating an electrochemical sensor for the determination of DA and AC in real biological samples.

Partially Reduced Graphene Oxide Membranes Crosslinked by an Anionic Porphyrin: Green Fabrication for High‐Performance Ion Sieving

AbstractGO membranes crosslinked by planar cation (e. g. TMPyP, a cationic porphyrin) meet the requirements of green fabrication, because TMPyP can pre‐assemble on GO sheets. However, their ion sieving performance are unsatisfactory. With shortened water channels, reduced graphene oxide (rGO) membranes owe high water flux, yet the retention of multivalent anions may goes down distinctly on account of Donnan effect decreasing obviously. Herein, we focus on the assembly between partially reduced graphene oxide (p‐rGO) and Anionic planar molecule (tetrasulfonic tetraphenyl porphyrin, TPPS), and then fabricate p‐rGO/TPPS composite membranes via assembling p‐rGO/TPPS sheets on base membrane. Anionic planar molecule is firstly used as crosslinking agent for graphene‐based membranes, which has the advantage of 100% atomic efficiency. The fabricated p‐rGO/TPPS membranes show better sieving performance than GO/TMPyP membranes on both side of rejection of Na2SO4 and water flux. Moreover, water flux go up to around another double though rejection decline slightly as the polyther sulfone (PES) base membrane with large surface pores is used.

A wearable All-Solid-State supercapacitor with extremely high stability based on 2D Co-HCF/GO

Herein, nanocomposites (denoted as Co-HCF/GO) with 2D GO sheets supporting cobalt hexacyanoferrate (Co-HCF) nanocubes are successfully synthesized via a hydrothermal method. Due to the cross-linking networks and synergistic effects between GO and Co-HCF in Co-HCF/GO, a high-performance supercapacitor with a specific capacity of 410.9 F g−1 @ 1 A g−1 and an ultrahigh cycling stability of 99.6% @ 10 A g−1 is achieved. With Co-HCF/GO as positive and negative electrodes, a symmetric flexible solid-state supercapacitor (FSSC) is assembled, which exhibits a high working voltage of 2.0 V, a high energy density of 45.8 Wh kg−1 at a power density of 2.1 kW kg−1 and an extremely high stability of 98.9% after 10,000 cycles when the charge–discharge cycle test is carried out under the condition of 10 A g−1. Furthermore, the FSSC assembled by Co-HCF/GO exhibits exceptional flexibility and wearability, with superhigh capacitance stability even goes bent at various angles (0°, 60°, 120° and 180°). Light emitting diodes (LEDs) can be easily lit up by the FSSC for a period of approximately 6.8 min. This approach offers promising opportunities for the development of energy storage materials and devices with excellent flexibility, excellent stability, high energy and power density.

Graphene Oxide/Silver Nanoparticles Platforms for the Detection and Discrimination of Native and Fibrillar Lysozyme: A Combined QCM and SERS Approach.

We propose a sensing platform based on graphene oxide/silver nanoparticles arrays (GO/AgNPs) for the detection and discrimination of the native and toxic fibrillar forms of an amyloid-prone protein, lysozyme, by means of a combination of Quartz Crystal Microbalance (QCM) and Surface Enhanced Raman Scattering (SERS) measurements. The GO/AgNPs layer system was obtained by Langmuir-Blodgett assembly of the silver nanoparticles followed by controlled adsorption of GO sheets on the AgNPs array. The adsorption of native and fibrillar lysozyme was followed by means of QCM, the measurements provided the kinetics and the mechanism of adsorption as a function of protein concentration as well as the mass and thickness of the adsorbed protein on both nanoplatforms. The morphology of the protein layer was characterized by Confocal Laser Scanning Microscopy experiments on Thioflavine T-stained samples. SERS experiments performed on arrays of bare AgNPs and of GO coated AgNP after native, or fibrillar, lysozyme adsorption allowed for the discrimination of the native form and toxic fibrillar structure of lysozyme. Results from combined QCM/SERS studies indicate a general construction paradigm for an efficient sensing platform with high selectivity and low detection limit for native and amyloid lysozyme.

Enhanced ultraviolet‐protectivetextiles based on reduced graphene oxide‐silver nanocomposites on polyethylene terephthalate usingultrasonic‐assisted in‐situthermal synthesis

AbstractThe present research develops a novel in‐situ synthesis method to produce a high performance nanocomposite coating on polyethylene terephthalate (PET) fabric as an enhanced UV‐protective textile. Reduced graphene oxide‐silver (rGO‐Ag) multi‐layer nanocomposite was in‐situ synthesized on the PET fabric through the direct redox reaction between the Ag+ions and GO sheets by using ultrasonic and thermal treatment. The X‐ray diffraction and field emission scanning electron microscope confirmed that the well‐synthesized Ag nanoparticles (AgNPs) loaded on PET fabric in presence of the GO sheets by using ultrasonic waves without reducing and capping agents. In this research, GO sheets were used as reducing and capping agents along with the ultrasonic treatment at low temperature condition. The final average size of the synthesized AgNPs in solution, on the PET surface and in the freestanding film is lower than 100 nm. The ultraviolet protection factor (UPF) of the PET fabric incorporating multi‐layer rGO‐Ag nanocomposite as a UV blocking system could reach to 6145.66, up to the 183‐fold higher than uncoated PET fabric (UPF 33.63). In addition, the final fabric demonstrates a good air permeability and antibacterial properties due to the effective coating of rGO‐Ag nanocomposite on PET surface.

Characteristics of Mg1−xCoxO powder prepared using coprecipitation method for glass film formation on and magnetic performance improvement of electrical steel

To save energy and reduce noise in high-efficiency transformers that use grain-oriented steel (GO), iron core loss reduction and magnetic flux density improvement of the GO are necessary. However, the addition of other elements (such as Co, Ni, and Mn) to the GO, which is mainly composed of Fe and Si, to improve its magnetic performance makes it difficult to roll GO into sheets because of the resulting decrease in ductility. Therefore, we synthesized Mg1−xCoxO two-component powders via coprecipitation to form an annealing separator on GO sheets and simultaneously improve their magnetic properties. The Mg0.7Co0.3O powder, which includes nano-sized polygonal particles with high crystallinity, was manufactured under base conditions and inert heat-treatment conditions at 800 °C to facilitate the preparation of an aqueous slurry. Compared to MgO powders, the Mg0.7Co0.3O powder forms forsterite more easily because of the low activation barrier of the solid-state reaction between it and SiO2 because of Co addition. In addition, Mg0.7Co0.3O-based forsterite glass film, which was coated on the GO sheet in a reduction environment, improved the magnetic properties of the GO sheet, such as core loss and magnetic flux density, because of Co diffusion from the forsterite to the GO sheet.

Versatile and robust poly(ionic liquid) coatings with intelligent superhydrophilicity/superhydrophobicity switch in high-efficient oil-water separation

• Versatile methods are applied on different substrates to fabricate intelligent materials for oil-water separation. • The PCMs exhibited switchable superhydrophilic/superhydrophobic properties . • The PCMs could switch the separation performances between “oil-removing” and “water removing” by anion exchange. • The PCMs would meet different requirements in oil-water separations: fast separation, ultra-efficient separation, water/oil adsorption and recycle . Superhydrophilic/superhydrophobic surfaces with unique superiority have been applied for oil-water separation over a long time. Facing the increasingly complicated requirements in diverse separation fields, developing intelligent surfaces with switchable superhydrophilic/superhydrophobic properties are highly needed. In this work, versatile and robust poly(ionic liquid) (PIL) coatings were designed and a series of intelligent materials with switchable superwettabilities were generated for high-efficient oil-water separation. The PIL coatings were obtained by polymerization of PIL monomer on the roughened GO sheets, for which were realized by the immobilization of Fe 3 O 4 nanoparticles. Three materials with different structures (cotton fabric (CF), nylon fabric (NF) and cotton ball (CB)) were chosen as the coating substrates. After “dip-coating” process, the PIL coated materials (PCMs) exhibited switchable superhydrophilic/superhydrophobic performances due to the anion-responsive behavior of PIL and the roughness enhanced effect. Thus, the PCMs showed high-efficient separation performances upon multiple oil-water separation cycles, and the separation could be switched between “water-removing” and “oil-removing” by anion exchange. Meanwhile, the PIL@CF had high permeate fluxes, which could separate layered water-oil mixtures rapidly under gravity; the PIL@NF had the highest separation efficiency; the PIL@CB possessed great potential to be used as efficient absorbents for water/oil adsorption and recycle.

Construction of CO3O4 derived ZIF/GO electrode for outstanding stability in supercapacitors devices

The growing global demand for energy supply and environmental protection has led to the use of high-efficiency energy storage devices, which supercapacitors are used as one of these devices with high storage capacity and exceptional stability. To be used for this purpose, an easy and rapid synthetically method was used to produce the CO3O4/GO nanocomposite, and its electrochemical performance as the electrode material in hybrid-supercapacitors was further investigated. In this nanocomposite, the CO3O4 crystals with less than 500 nm particle size are uniformly in contact with the wrinkled GO sheets, that their structure and morphology were investigated by surface analyzes. In addition, the functional groups, crystallographic properties, and elemental composition were investigated using the FTIR, XRD, and EDX analyzes. To confirm the supercapacitive effectiveness of the prepared samples, the electrochemical measurements (EIS, CV, and GCD) were done. The results have shown that the values of specific capacity, energy and power densities of Co3O4/GO hybrid nanocomposite are 234 mAh g−1, 16.075 W h kg−1 and 251 W kg−1, respectively. Also, the Co3O4/GO has the lowest amount of resistance compared to other electrodes. Nearly constant efficiency at 104% after 1000 cycles indicates that the nanocomposite has excellent cyclic stability. The proper electrochemical efficiency of the nanocomposite corresponds to the synergistic effect on the composition.

Microwave assisted ultrafast synthesis of graphene oxide based magnetic nano composite for environmental remediation

We have successfully synthesized multi-layer graphene oxide and graphene oxide based magnetic nanocomposite (M/GO) by microwave-assisted modified Hummers’ method for removal of toxic lead (Pb 2+ ) and cadmium (Cd 2+ ) ions from aqueous solution. The X-ray diffraction spectra of synthesized graphene oxide and M/GO confirm increased interlayer spacing along c-axis. Raman spectra revealed the good quality of synthesized GO and M/GO. The wrinkles were seen in the SEM images of synthesized graphene oxide. The presence of conjugated double bond (C C) and carbonyl (C O) were confirmed by using the UV–Vis spectroscopic spectra. Brunauer–Emmett–Teller (BET) analysis showed high (126 m 2 /g) surface area M/GO composite which accounts for large number of active binding sites for the adsorption of heavy metal ions. The adsorption studies revealed that Pb 2+ ions were efficiently adsorbed on GO sheets. Interestingly, M/GO showed better adsorption for cadmium ions. Addition of stock solution of Pb 2+ and Cd 2+ ions to M/GO solution, removal of M/GO containing Pb 2+ , and Cd 2+ ions using Neodymium magnet.