Magnetic Graphene Oxide Nanocomposite Research Articles

Solid-phase extraction of phytosterols from rapeseed oil deodorizer distillates with magnetic graphene oxide nanocomposite

A fast and facile method was employed for the synthesis of magnetic graphene oxide (MGO). The synthesized MGO is characterized by different techniques and used as a solid-phase adsorbent for the extraction of β-sitosterol from rapeseed oil deodorizer distillates (RODD) followed by gas chromatography-mass spectrometry analysis. Several parameters affecting the extraction efficiency, including the amount of adsorbent, extraction time and temperature, desorption solvent and desorption time, were investigated. The procedure exhibited desirable extraction efficiency within 30 min at 35 °C. Recoveries higher than 80% were obtained with acetone as eluent and the method was successfully applied to concentrate the β-sitosterol in RODD CO2-supercritical extract. Compared to C18-silica and graphitic carbon, the composite showed satisfactory results for the extraction of β-sitosterol from oil samples.

The fabrication of a thiol-modified chitosan magnetic graphene oxide nanocomposite and its adsorption performance towards the illegal drug clenbuterol in pork samples

A novel thiol (provided by (3-mercaptopropyl) trimethoxysilane, MPTS)-modified chitosan magnetic graphene oxide nanocomposite (Fe3O4@SiO2/GO/CS/MPTS) was synthesized and characterized for the first time as an efficient magnetic sorbent for the enrichment and extraction of trace levels of clenbuterol in pork samples (muscle, fat, heart and liver). Various greatly influential parameters were optimized using a Box-Behnken design (BBD) through the response surface methodology (RSM) to obtain more satisfactory recovery. Under optimum conditions, the method detection limits (MDLs) were in the range of 0.054-0.136 ng g-1. The recoveries of three spiked levels ranged from 84.7% to 101.1%, and the relative standard deviations (RSDs) were lower than 9.3%. The results of the adsorption experiments showed that the maximum adsorption capacity of Fe3O4@SiO2/GO/CS/MPTS for clenbuterol was 214.13 mg g-1. The adsorption process was most consistent with pseudo second-order kinetics and Langmuir adsorption isotherm, indicating a homogeneous process with a chemisorptive nature. Also, the nanocomposite exhibited high adsorption capability for clenbuterol compared with Fe3O4@SiO2/GO and Fe3O4@SiO2/GO/CS. In addition, regeneration of the nanocomposite was effectively achieved, and it retained about 82% of its initial capacity after four cycles. All these results indicate that the synthetic nanocomposite is a promising efficient adsorbent for the adsorption of clenbuterol with high adsorption capacity and low cost.

Removal of Hg(II) and methylene blue from single aqueous solution by ethylenediamine modified magnetic graphene oxide nanocomposites

Herein, the ethylenediamine modified magnetic graphene oxide (Fe3O4/GO-NH2) materials were used to eliminate Hg(II) and methylene blue (MB) dye from single aqueous solutions. The various adsorption conditions of Fe3O4/GO-NH2 materials were explored and the experimental process highly depended on the initial pH, contact times and initial concentrations of Hg(II) and MB. The Langmuir and Freundlich isotherm models were employed to explore the adsorption behaviours and the kinetics experimental process were described by the pseudo-first-order and pseudo-second-order model. The experiments show that adsorption amounts of Fe3O4/GO-NH2 materials for Hg(II) and MB reached 147.68 mg·g−1 and 236.97 mg·g−1, respectively. The adsorption process was well correlated with pseudo-second-order kinetic model and the Langmuir isotherm model, which indicates the removal processes of Fe3O4/GO-NH2 nanocomposites for Hg(II) and MB were monolayer chemisorption.

Removal of Hg(II) and methylene blue from single aqueous solution by ethylenediamine modified magnetic graphene oxide nanocomposites

Herein, the ethylenediamine modified magnetic graphene oxide (Fe3O4/GO-NH2) materials were used to eliminate Hg(II) and methylene blue (MB) dye from single aqueous solutions. The various adsorption conditions of Fe3O4/GO-NH2 materials were explored and the experimental process highly depended on the initial pH, contact times and initial concentrations of Hg(II) and MB. The Langmuir and Freundlich isotherm models were employed to explore the adsorption behaviours and the kinetics experimental process were described by the pseudo-first-order and pseudo-second-order model. The experiments show that adsorption amounts of Fe3O4/GO-NH2 materials for Hg(II) and MB reached 147.68 mg·g−1 and 236.97 mg·g−1, respectively. The adsorption process was well correlated with pseudo-second-order kinetic model and the Langmuir isotherm model, which indicates the removal processes of Fe3O4/GO-NH2 nanocomposites for Hg(II) and MB were monolayer chemisorption.

One-pot three-component synthesis of propargylamines using an efficient and reusable copper bio-functionalized magnetic graphene oxide nanocomposite

In this work, magnetic graphene oxide was produced through chemical oxidation of the graphite powder, exfoliation under ultrasonic waves and then magnetization in the presence of ion salts. Magnetic graphene oxide was functionalized with cysteine and used as efficient support for the immobilization and suitable dispersing of copper ions. This nanocatalyst was characterized using FT-IR, TEM, EDX, XRD, VSM, XPS and ICP-OES analysis. Very low loading of prepared nanocomposite was showed high activity in the synthesis of propargylamine derivatives via A3-coupling reaction. It simply recovered from the reaction mixture by using an external magnetic field and reused without any pre-activation in next tests with acceptable yields.

Polystyrene@graphene oxide-Fe3O4 as a novel and magnetically recyclable nanocatalyst for the efficient multi-component synthesis of spiro indene derivatives

Polystyrene (PS)-coated magnetic graphene oxide (GO-Fe3O4) nanocomposite has been prepared and characterized by FT-IR, TEM and VSM techniques, and its catalytic activity has been evaluated in the multi-component synthesis of two series of indene derivatives. The three-component condensation of ninhydrin/isatin, malononitrile and active methylene-containing compounds and also the four-component condensation of ninhydrin, o-phenylenediamines, malononitrile and active methylene-containing compounds were satisfactorily performed in the presence of PS@GO-Fe3O4 magnetic nanocomposite, and corresponding 2′-aminospiro[indene-2,4′-pyran]-3′-carbonitriles, 2′-aminospiro[indoline-3, 4′-pyran]-3′-carbonitriles and 2′-aminospiro[indeno[1,2-b]quinoxaline-11,4′-pyrane]-3′-carbonitriles were obtained in good-to-excellent yields, respectively. Very shorter reaction times than the reported methods, easy workup procedure and easy separation and reusability of the catalyst are noteworthy advantages of the current method.

Ligandless dispersive solid phase extraction of cobalt ion using magnetic graphene oxide as an adsorbent followed by its determination with electrothermal atomic absorption spectrometry

ABSTRACT Ligandless dispersive solid phase extraction technique was used for preconcentration of cobalt ion (Co2+) followed by its determination using electrothermal atomic absorption spectrometry (ETAAS). Graphene oxide (GO) was synthesised from graphite by the Hummer method and chemically magnetised to synthesise of the magnetic graphene oxide (MGO). The synthesised MGO was characterised by the Fourier transform-infrared spectrophotometry (FT-IR), vibrating sample magnetometer (VSM), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) and then used as an adsorbent for solid phase extraction of Co2+. The main parameters affecting the extraction recovery of Co2+ including pH of sample solution, amounts of adsorbent, extraction time and type and concentration of desorption solvent were investigated and optimised. The calibration curve was plotted in the range of 0.08–1.2 µg L−1 Co2+ with a correlation coefficient of 0.9987. The intra-day precision based on six replicate analysis of 0.2 µg L−1 Co2+ was 3.8% and the limit of detection (LOD) was 0.023 µg L−1 Co2+ (n = 5). Also, the adsorption isotherms and adsorption kinetics were investigated and based on the obtained results, the adsorption of Co2+ onto the MGO nanocomposite followed by both Langmuir and Freundlich isotherms with a maximum adsorption capacity of 114.9 mg g−1 Co2+. The results of kinetic models also show that the adsorption of Co2+ followed by the pseudo second order kinetic model. The accuracy of the proposed method was successfully checked by the analysis of two certified reference materials including certified reference material-trace metals in drinking water (CRM-TMDW) and spinach leaves 1570a samples (Student t-test with 95% confidence limit, n = 5). Finally, the proposed rapid and efficient solid phase extraction technique was used for the determination of trace levels of Co2+ in the human saliva, urine and different real samples.

Functionalized magnetic nanoparticle-reduced graphene oxide nanocomposite for enzymatic biofuel cell applications

Enzymatic biofuel cells (EBFCs) produce electrical energy from green and renewable fuels, by utilizing redox enzyme. However, the main issue of low power output and stability of the electrode still prevails in this field. Extensive research is going on to overcome this problem by improving the electrical communication between the enzyme and the current collector. In the light of this, a new electrode design based on reduced graphene oxide (rGO) and functionalized magnetic nanoparticles (f-Fe3O4 NPs) in polyaniline matrix has been proposed and employed for the purpose of the EBFCs application, in order to achieve efficient electron shuttling between enzyme glucose oxidase (GOx) and the electrode surface. The as-prepared rGO/PANI/f-Fe3O4 nanocomposite was examined by analytical techniques viz, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and the electrochemical behaviour of the rGO/PANI/f-Fe3O4 nanocomposite and rGO/PANI/f-Fe3O4/Frt/GOx bioanode was determined by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and linear sweep voltammetry (LSV). The bioanode attained a maximum current density of 32.9 mA cm−2 at the optimum glucose concentration of 50 mM.

Removal of phosphate and nitrate ions aqueous using strontium magnetic graphene oxide nanocomposite: Isotherms, kinetics, and thermodynamics studies

AbstractMagnetic Fe3O4 nanoparticle decorated graphene oxide (GO) was modified with strontium nanoparticles (MGO‐Sr) and applied for enhanced removal of phosphate and nitrate ions from river and sewage water samples. The nanocomposite's features were investigated using Fourier transform‐infrared spectrometry, field emission‐scanning electron microscopy, energy‐dispersive X‐ray spectroscopy, and X‐ray diffraction. The effective parameters, adsorption efficiency, regeneration, and field application of MGO‐Sr were also studied. Adsorption isotherm and kinetic models were applied for evaluation of experimental adsorption process. The data was in well comply with Langmuir isotherm and pseudo‐second‐order comparing with other models. Langmuir maximum adsorption capacity was obtained equal to 238.09 mg/g for phosphate and 357.14 mg/g for nitrate. Van't Hoff thermodynamic predicted an exothermic nature for adsorption process followed by a physisorption mechanism. The prepared nanocomposite provided a high‐removal efficiency toward phosphate and nitrate ions in river and sewage water. Hence, it is applicable in water remediation process.

Fabrication of novel magnetic graphene oxide nanocomposites for selective adsorption of mercury from aqueous solutions.

In this work, a novel functionalized graphene oxide (GO) was used as an effective and selective adsorbent for removal of mercury (Hg2+). The magnetic nanocomposite adsorbent (MNA) based on GO was prepared through surface reversible addition-fragmentation chain transfer copolymerization of acrylic monomers and then the formation of Fe3O4 nanoparticles. The structure of MNAs was characterized by using FTIR, SEM, TEM, VSM, XRD, and nitrogen adsorption/desorption isotherms. The results of ion adsorption of MNAs demonstrated high selectivity and adsorption efficiency for Hg2+ in the presence of competing ions. Furthermore, the removal of Hg2+ obeyed a pseudo-second-order model and fitted well to the Langmuir isotherm model with the maximum Hg2+ uptake of 389 mg g-1. The MNA was also confirmed as good materials for re-use and maintained 86% of its initial adsorption capacity for mercury after the fifth regeneration cycles. Finally, the experimental results demonstrated that the solution pH, ion concentration, and temperature had a major impact on Hg(II) adsorption capacity. The results indicate that the MNAs with high adsorption abilities could be very promising adsorbents for the selective recovery of ions in wastewater treatment process. Graphical abstract.

Silica-coated magnetic graphene oxide nanocomposite based magnetic solid phase extraction of trace amounts of heavy metals in water samples prior to determination by inductively coupled plasma mass spectrometry

The silica-coated magnetic graphene oxide (Fe3O4-GO@SiO2) composites were synthesized by a simple procedure in this work. The nanocomposite was characterized and applied for the rapid magnetic solid-phase extraction (MSPE) of chromium (Cr), cobalt (Co), nickel (Ni), copper (Cu), cadmium (Cd), lead (Pb), silver (Ag) ions at trace level in environmental water samples. Various experimental parameters affecting the extraction efficiency of the target metal ions by Fe3O4-GO@SiO2 were investigated and optimized, including sorbent dosage, pH of sample solution, sorption time, volume and eluent concentration, as well as elution time. Under the optimal conditions, the limits of detection (LODs, 3σ) for the target analytes were obtained in the range of 2.023–13.810 ng L−1. The recoveries of the target metals in four environmental water samples ranged from 83% to 109% and the relative standard deviations (RSDs) were lower than 7%. Moreover, in batch adsorption experiments, the adsorption of these seven metal ions was relatively speedy and the equilibrium was established after shaking 35 min which kinetics followed the pseudo second-order model, indicating a chemisorption nature. The adsorption process was simulated by the Langmuir isotherm accurately, and the calculated maximum adsorption (qmax) capacities of Fe3O4-GO@SiO2 were 182.98 mg g−1, 116.35 mg g−1, 226.08 mg g−1, 149.59 mg g−1, 100.81 mg g−1, 168.55 mg g−1 and 141.09 mg g−1 for Cr (III), Co (II), Ni (II), Cu (II), Cd (II), Pb (II) and Ag (I), respectively. Finally, the developed method was successfully applied for simultaneous and sensitive determination of target metals at trace level in environmental water samples.

Adsorption of arsenic using chitosan magnetic graphene oxide nanocomposite

Chitosan-magnetic-graphene oxide (CMGO) nanocomposite was prepared for arsenic adsorption. The nanocomposite was characterized through BET, FTIR, FESEM, EDX, and VSM analyses. These characterizations confirmed the formation of CMGO nanocomposites with high specific surface area (152.38 m2/g) and excellent saturation magnetization (49.30 emu/g). Batch adsorption experiments were conducted to evaluate the performance of the nanocomposite in the adsorption of arsenic from aqueous solution. The effects of operational parameters, adsorption kinetic, equilibrium isotherm and thermodynamics were evaluated. The removal efficiency of arsenic increased with increasing adsorbent dosage and contact time. However, the effect of pH followed a different pattern, with the removal efficiency increasing from acidic to neutral pH, and then decreasing at alkaline conditions. The highest adsorption capacity (45 mg/g) and removal efficiency (61%) were obtained at pH 7.3. The adsorption kinetic followed a pseudo-second-order kinetic model. The analysis of adsorption isotherm shows that the adsorption data fitted well to Langmuir isotherm model, indicating a homogeneous process. Thermodynamic analysis shows that the adsorption of As(III) is exothermic and spontaneous. The superparamagnetic properties of the nanocomposite enabled the separation and recovery of the nanoparticles using an external magnetic field. Thus, the developed nanocomposite has a potential for arsenic remediation.

Aptamer functionalized magnetic graphene oxide nanocomposites for highly selective capture of histones.

The binding coverage of aptamer was an important restricted factor for aptamer-based affinity enrichment strategy for capturing target molecules. Herein, we designed and prepared aptamer functionalized graphene oxide based nanocomposites (GO/NH2 -NTA/Fe3 O4 /PEI/Au), and the coverage density of aptamer was high to 33.1nmol/mg. The high aptamer coverage density was contributed to the large surface area of graphene oxide. The successive modification of Nα,Nα-Bis(carboxymethyl)-L-lysine, magnetic nanoparticles, polyethylenimine, and Au nanoparticles ensured the histone purification with fast speed and high purity. Histones could be captured rapidly and specifically from nucleoproteins by our aptamer based purification strategy, while traditional acid-extraction could not specifically enrich histones. Compared with traditional acid-extraction method, rapid and efficient discovery of histones and their post-translational modifications, such as several kinds of methylation at H3.1K9 and H3.1K27, were achieved confidently. It demonstrated that our aptamer functionalized magnetic graphene oxide nanocomposites have a great potential for histone analysis.

Application of graphene oxide modified with the phenopyridine and 2-mercaptobenzothiazole for the adsorption of Cr (VI) from wastewater: Optimization, kinetic, thermodynamic and equilibrium studies

In this study response surface methodology (RSM) was discussed as an efficient method for optimization of chromium adsorption onto magnetic graphene oxide(GO-Fe3O4) nanocomposites functionalized with two chelating ligands of the phenopyridine (GFP) and 2-mercaptobenzothiazole (GFM). The obtained GFP and GFM nanocomposites characterized using TEM, SEM, FTIR, EDAX, AFM, DLS and TGA. The optimization of adsorption of Cr (VI) onto GFM and GFP was done with the aim of high adsorption performance, minimizing the adsorbent dose and increase of the initial Cr (VI) concentration. Results indicated reduced full second-order (for GFP) and full second-order (for GFM) models were well-fitted with the experimental data. The optimum operating points were achieved (pH, 6.55; adsorbent dosage, 0.098 g L−1; contact time, 178.4 min and Cr (VI) concentration, 1 mg L−1) and (pH, 6.79; adsorbent dosage, 2.98 g L−1; contact time, 118.6 min and Cr (VI) concentration, 4.41 mg L−1) for GFP and GFM, respectively. The both adsorbents indicated best fit with Langmuir model. Also, the kinetic models were followed pseudo second order model and pseudo first order model for GFP and GFM, respectively. The thermodynamic studies indicated the sorption of Cr (VI) onto GFP and GFM was endothermic and spontaneous.

An efficient 2-mercapto-5-phenylamino-1,3,4-thiadiazole functionalized magnetic graphene oxide nanocomposite for preconcentrative determination of mercury in water and seafood samples

In this work, an efficient 2-mercapto-5-phenylamino-1,3,4-thiadiazole (2-MPATD) modified magnetic graphene oxide was synthesized and utilized to preconcentrative determination of inorganic mercury (Hg(II) ions) in water and seafood samples. At first graphene oxide sheets were decorated with Fe3O4 NPs to obtain magnetic graphene oxide, and then magnetic graphene oxide sheets were coated with a silica layer. Afterwards, magnetic graphene oxide@SiO2 was functionalized by 2-MPATD (mGO@SiO2@2-MPATD nanocomposite). FT-IR, SEM, elemental analysis and vibrating sample magnetometry techniques were employed to characterize the nanosorbent. Experimental design was performed to monitor and find the parameters that affect the extraction performance. After sorption and elution steps, the concentration of Hg(II) was measured by employing cold vapor atomic absorption spectrometry. The highest extraction performance was achieved under the following conditions: sorption time (10.0 min), pH value (6.3), sorbent amount (16 mg); eluent (HNO3 solution; 1.25 mol L-l; 1.7 mL), and elution time (14.0 min). The obtained detection limit was 0.008 ng mL−1. Finally, the method was utilized for rapid determination of mercury ions in various real samples, satisfactorily.

Construction of CLEAs-lipase on magnetic graphene oxide nanocomposite: An efficient nanobiocatalyst for biodiesel production

In the present work, cross linked enzyme aggregates of Lipase (CLEAs-lip) was synthesized and immobilized on the magnetic amino functionalized graphene oxide (maGO-CLEAs-lip) nanocomposites. The immobilized lipase showed a broad range of temperature activity about 40–60 °C, as compared to free enzyme. In the case of maGO-CLEAs-lip nanocomposite, the observed lower Km value state 2.25 folds affinity for the p-nitrophenyl palmitate. Enzyme activity of maGO-CLEAs-lip nanocomposite was the highest up to 5 cycles. Storage stability results displayed maGO-CLEAs-lip retained about 75% of its original activity after 30 days of incubation. Remarkably, maGO-CLEAs-lip formed the highest biodiesel construction (78%) from R. communisoil after 24 h of incubation. The biodiesel yield of this nanocomposite was 3.0 folds higher than free enzyme, making it talented as an excellent nanobiocatalyst for efficient production of biodiesel.

β-Cyclodextrin⁻Hyaluronic Acid Polymer Functionalized Magnetic Graphene Oxide Nanocomposites for Targeted Photo-Chemotherapy of Tumor Cells.

A multifunctional targeted drug delivery platform (CDHA–MGO) has been successfully constructed by grafting β-cyclodextrin–hyaluronic acid polymers (CDHA) to Fe3O4–graphene oxide (MGO). The obtained CDHA–MGO nanocomposite has good water-dispersibility, easy magnetic separation, high near-infrared (NIR) photothermal heating, and excellent biocompatibility. The β-cyclodextrin-hyaluronic acid polymers efficaciously enhance the doxorubicin (DOX) loading amount up to 485.43 mg·g−1. Meanwhile, the Fe3O4–graphene oxide provides a facile photothermal response mechanism to handle the NIR-triggered release of DOX in weak acidic solvent environments. Significantly, the DOX-loaded nanocomposite (DOX@CDHA–MGO) has displayed CD44 receptor-mediated active targeting recognition and chemo-photothermal synergistic therapy of hepatoma cells. These findings suggest that the as-prepared drug delivery platform would be of valuable potential for cancer-targeted photo-chemotherapy.

Fabrication of magnetic graphene oxide nanocomposites functionalized with a novel chelating ligand for the removal of Cr(VI): Modeling, optimization, and adsorption studies

Fabrication of magnetic graphene oxide nanocomposites functionalized with a novel chelating ligand for the removal of Cr(VI): Modeling, optimization, and adsorption studies

A comprehensive review of applications of magnetic graphene oxide based nanocomposites for sustainable water purification

With the rapid growth of industrialization, water bodies are polluted with heavy metals and toxic pollutants. In pursuit of removal of toxic pollutants from the aqueous environment, researchers have been developed many techniques. Among these techniques, magnetic separation has caught research attention, as this approach has shown excellent performance in the removal of toxic pollutants from aqueous solutions. However, magnetic graphene oxide based nanocomposites (MGO) possess unique physicochemical properties including excellent magnetic characteristics, high specific surface area, surface active sites, high chemical stability, tunable shape and size, and the ease with which they can be modified or functionalized. As results of their multi-functional properties, affordability, and magnetic separation capability, MGO's have been widely used in the removal of heavy metals, radionuclides and organic dyes from the aqueous environment, and are currently attracting much attention. This paper provides insights into preparation strategies and approaches of MGO's utilization for the removal of pollutants for sustainable water purification. It also reviews the preparation of magnetic graphene oxide nanocomposites and primary characterization instruments required for the evaluation of structural, chemical and physical functionalities of synthesized magnetic graphene oxide nanocomposites. Finally, we summarized some research challenges to accelerate the synthesized MGO's as adsorbents for the treatment of water pollutants such as toxic and radioactive metal ions and organic and agricultural pollutants.

Magnetic graphene oxide nanocomposites as the adsorbent for extraction and pre-concentration of azo dyes in different food samples followed by high-performance liquid chromatography analysis

ABSTRACTThis work presents a method of magnetic solid-phase extraction (MSPE) combined with high-performance liquid chromatography (HPLC) to analyse five synthetic azo dyes (tartrazine, amaranth, carmine, sunset yellow, allura red) in different food samples. The magnetic graphene oxide nanocomposite (GO@Fe3O4) was prepared by a one-step solvothermal method and used as the sorbent for extraction and pre-concentration of azo dyes in food samples. The as-prepared GO@Fe3O4 nanocomposite was characterised by transmission electron microscope, Fourier transform-infrared spectroscopy, X-ray diffraction, vibrating sample magnetometer, and Brunuer-Emmett-Teller analysis. The extraction and desorption parameters were investigated, including the material amount, extraction time, pH of the solution, desorption temperature, and desorption solvents. Under the optimised conditions, the limits of detection (LODs) were 1.14–2.23, 0.36–0.77 and 0.68–1.26 ng/g for candy, jelly, and plum candy, respectively. The limits of quantification (LOQs) were 4.02–7.73, 1.21–2.50 and 2.31–4.20 ng/g for candy, jelly, and plum candy, respectively. For the analysis of spiked jelly, recoveries were between 73.2% and 107.7%, with RSDs lower than 1.34 %. The developed method was successfully applied to the analysis of real samples including jelly, candy and plum candy.