Magnetic Graphene Oxide Composites Research Articles

Magnetic Graphene Oxide Nanocomposites for Selective miRNA Separation and Recovery.

In this study, we developed magnetic graphene oxide composites by chemically attaching Fe3O4 nanoparticles to graphene oxide nanosheets. Characterization techniques, including Fourier transform infrared spectroscopy (FTIR), X-ray powder diffraction (XRD), Raman spectroscopy, thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), and transmission electron microscopy (TEM), confirmed the successful synthesis of Fe3O4@GO composites with desirable properties. The resulting composites exhibited superparamagnetic behavior, solubility, and compatibility for efficient miRNA separation. Using miR-29a as a model, we demonstrated the effective binding of miR-29a to the magnetic graphene oxide (GO) composites at an optimal concentration of 1.5 mg/mL, followed by a simple separation using magnetic forces. Additionally, the addition of 5.0 M urea enhanced the miRNA recovery. These findings highlight the potential use of our magnetic graphene oxide composites for the efficient separation and recovery of miR-29a, suggesting their broad applicability in various miRNA-based studies. Further exploration can focus on investigating endogenous miRNAs with aberrant expression patterns, contributing to the advancements in precision medicine.

Efficient Removal of Representative Chemical Agents by Rapid and Sufficient Adsorption via Magnetic Graphene Oxide Composites

Chemical agents pose a significant threat to social security, highlighting the crucial role of representative chemical agents adsorption in ensuring the safety our environment. This study explored the application of Magnetic Graphene Oxide Nanoplatelet Composites (MGONCs) in adsorbing the representative chemical agents such as Lewisite (L), O-ethyl S-2-diisopropylaminoethyl methylphosphonothiolate (VX), Sarin (GB), and Soman (GD). MGONCs were synthesized through a physical blending method, with the combination of graphene oxide (GO) and Fe3O4 nanoparticles at a mass ratio of 1:1. Optimization of the adsorption process involved investigating the effects of contact time, temperature, and adsorbent dosage. Remarkably, the adsorption rate of L and VX exceeded 99% when the dosage of MGONCs was 2.5 mg, with a contact time of 30 s at room temperature. Furthermore, GB and GD achieved maximum adsorption rates after a contact time of 20 min, with the dosages of MGONCs at 10 mg and 20 mg, respectively. Characterization of the magnetic composite was accomplished through XRD, TEM, VSM, FTIR, TGA, and BET analyses. Kinetical analysis revealed that the adsorption mechanism of GB and GD on MGONCs followed pseudo-second-order (PSO) kinetics, exhibiting a high regression coefficient. The calculated qe values were 0.103125 mg/g and 0.081349 mg/g, respectively. This research demonstrated the feasibility of utilizing MGONCs as highly efficient adsorbents for representative chemical agents, particularly in on-site sampling scenarios.

Effective Removal of Hexavalent Chromium from Aqueous Solutions Using Quaternary Ammonium-Functionalized Magnetic Graphene Oxide Composites

Novel quaternary ammonium/magnetic graphene oxide composites (M-PAS-GO) that efficiently remove Cr(VI) ions were fabricated through the introduction of the (3-aminopropyl) triethoxysilane and Fe3O4 nanoparticles on the surface of GO, and then modified with n-butyl bromide. The fabricated M-PAS-GO was comprehensively characterized by SEM, TEM, EDX, XRD, Raman spectroscopy and FTIR, and the results manifest that the quaternary ammonium group was introduced onto the surface of GO. Under the reaction conditions of pH 3.20, temperature of 25 °C and M-PAS-GO dosage of 0.01 g/50 mL, 90% of 10 mg/L Cr(VI) ions were removed from the solution within 20 min. The kinetics study indicates that the adsorption process followed the pseudo-second-order model and was surface reaction-controlled. The thermodynamic parameters calculated from temperature-dependent adsorption isotherms suggest that the adsorption process was an exothermic and spontaneous process. The maximum adsorption capacities of Cr(VI) ions on M-PAS-GO composites calculated by the Langmuir model were 46.48 mg/g. Moreover, the reusability and stability of M-PAS-GO demonstrates its economic sustainability. This study suggests that M-PAS-GO is a potential candidate adsorbent for the separation of Cr(VI) from wastewater.

PH-responsive magnetic graphene oxide composite as an adsorbent with high affinity for rapid capture of nucleosides.

Anovel pH-responsive magnetic graphene oxide composite (MGO@PEI-BA) isproposed for the first time as an adsorbent for the rapid capture and detection of nucleosides (cytidine, uridine, guanosine, and adenosine). The morphology, structure, and magnetic properties of thecomposite were evaluated using various characterization techniques. The results indicated that the composite was successfully fabricated. A series of parameters that affect extraction and elution were optimized through one-factor-at-a-time and Box-Behnken design of response surface methodology (BBD-RSM). The unique layered structures and easily accessible active sites of the composite facilitated molecular transport, resulting in instantaneous equilibrium of nucleosides adsorption within 5 min. Based on this study, a magnetic dispersive micro-solid-phase extraction (MD-μ-SPE) method assisted by the MGO@PEI-BA was developed in combination with UHPLC-UV analysis for the determination of nucleosides in rat urine. Under the optimum conditions, a wide linear range (10-2000 ng mL-1), good linearity (r > 0.99), low detection limits (1-3 ng mL-1), low relative standard deviations (RSDs ≤ 3.9%), and satisfactory recoveries (82.7-96.3%) were achieved. These results demonstrate that the MGO@PEI-BA is an excellent adsorbent for extracting nucleosides from biological samples.

Functionalized magnetic graphene oxide composites for selective toxic metal adsorption

In this work, composites of magnetite and graphene oxide were modified with amino groups to improve chromium selectivity in a multielement solution containing Cd(II) and Cu(II) ions. The results achieved from characterization techniques such as Fourier transform infrared, Mössbauer spectroscopy, and X-ray photoelectron spectroscopy, confirmed the effectiveness of the synthesis and evidenced different moieties able to promote metal adsorption. Comparing the unmodified composites with the silanized one, it was observed an enhancement in Cr(VI) uptake of 86% relative to Cd(II) and 23% relative to Cu(II). This effect was attributed to the hard-hard interactions of Cr(VI) with nitrogen and to the presence of NH3+ groups that improve the adsorption of chromium negative species. The metal adsorption by the composites followed the Langmuir isotherm model and a pseudo-second order kinetic, and the surface charge played an important role in the adsorption. Finally, reuse experiments showed an adsorption of approximately 100% of Cr(VI) over 5 cycles, underlining the remarkable stability of the produced amino grafted material.

Unique magnetic graphene oxide with enhanced carboxylate functional groups for uranium separation by solid phase extraction

The cation exchange capability of carboxylate functional group in graphene oxide is explored for uranium adsorption. The magnetic graphene oxide (MGO) composite was prepared from graphene oxide and magnetite (Fe3O4) to exercise magnetic separation of uranium from the aqueous phase. Characterization by XRD, Raman, SEM and TEM indicate fine aggregate of MGO in which Fe3O4 a dispersed between two GO layers. The proficiency of uranium adsorption in presence of major sea water constituents was probed by varying the pH, kinetics of adsorption, and uranium concentration. The kinetics of adsorption was found to fit into the pseudo-second-order model and the adsorption isotherm resembles Langmuir model. The proposed kinetic model demonstrates the predominant role of chemical reactions at the sites of adsorption over the diffusion of metal ions. The performance of MGO in adsorbing uranium, after several cycles of adsorption and recycling is found to be very promising for scaling up applications.

Magnetic Graphene Oxide Modified with a Surface-Active Ionic Liquid for Ultrasound-Assisted Solid-Phase Extraction (UA-SPE) to Preconcentrate Lenalidomide from Human Plasma with Determination by High-Performance Liquid Chromatography with Ultraviolet Detection (HPLC-UV)

A new magnetic graphene oxide (MGO) composite was developed as an adsorbent for the preconcentration of lenalidomide (LND) by ultrasound-assisted solid-phase extraction (UA-SPE) prior to determination by high-performance liquid chromatography with ultraviolet detection (HPLC-UV). The adsorbent was fabricated through chemical functionalization of a new surface-active ionic liquid (SAIL), i.e. 1-methyl-3-(trimethoxysilyl propyl)-imidazolium dodecyl sulfate (TMES-Im-DS) on MGO. The synthesized material presented the benefits of excellent adsorption for LND. The characterization of the synthesized functionalized magnetic nanocomposite was performed by Fourier transform-infrared spectroscopy, field emission scanning electron microscopy, Brunauer–Emmett–Teller (BET), vibrating sample magnetometry, and energy-dispersive X-ray spectroscopy. After optimization of the parameters, the limits of detection (LOD) and limit of quantification (LOQ) were 0.2 and 0.8 µg L−1 and 0.6 and 2.5 µg L−1in water and plasma samples, respectively. The enrichment factors (EFs) were from 90 to 180 in the samples. The relative standard deviation (RSD%, n = 5) as intra- and inter-day precision were from 6.3% to 7.5% and 7.1% to 8.5% in water and plasma, respectively. Lastly, the developed method presented good results for the preconcentration of LND in plasma with satisfactory repeatability.

Adsorption characteristics in the removal of chlorpyrifos from groundwater using magnetic graphene oxide and carboxy methyl cellulose composite

The widespread occurrence of chlorpyrifos (CPF) in water sources makes it critical to develop efficient and low-cost adsorbents. This work developed a simple approach to prepare a green, efficient, and recyclable composite of magnetic graphene oxide and carboxymethyl cellulose (MGOC) for CPF removal from groundwater. Various analytical techniques such as field emission scanning electron microscope (FE-SEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and Brunauer, Emmett and Teller (BET) analysis were used to characterize the MGOC composite. The experimental parameters used in the batch isotherm study were optimized using the response surface methodology (RSM) and central composite design (CCD). A maximum CPF removal efficiency of 98.3 % was predicted at an initial CPF concentration of 14.0 mg/L, MGOC dosage of 0.40 g/L, contact time of 40 min, and solution pH of 6.0. The RSM analysis provided a second-order polynomial model with a p-value ˃ 0.0001, F-value of 175.152, and R2 of 0.9786, to predict the CPF removal efficiency at various experimental conditions. The good adsorption ability was attributed to abundant active sites from MGOC composite. Of the eight isotherm models evaluated, the Langmuir isotherm model gave a best fit with a maximum monolayer adsorption capacity (qm) of 108.3 mg g−1.In the adsorption kinetic studies, the second-order kinetic model gave a best fit for the experimental data. Further, the MGOC composite proved to be effective in the removal of CPF from groundwater samples. The adsorption mechanism was discussed. The desorption and regeneration studies indicated that MGOC composite is viable upto five cycles with a 14 % drop in the adsorption capacity. Considering the high removal efficiency and adsorption capacity, easy separation, and proper regeneration, MGOC composite could be a promising adsorbent for removing CPF from groundwater and polluted water by pesticides.

Preparation and adsorption properties of magnetic graphene oxide composites for the removal of methylene blue from water

Using graphite powder, chitosan, and diatomite as raw materials, graphene oxide was first prepared by Hummer’s method and GO was carboxylated and modified into hydroxylated graphene oxide (GOH). It was then modified into GOH via carboxylation, and then diatomite (DE) and the prepared magnetic chitosan (MCS) were supported on GOH by blending to generate the magnetic graphene oxide composite GOH/DMCS. This novel composite was then studied to determine its methylene blue wastewater adsorption capability. Results showed that at 45 °C, a dosage of adsorbent of 1 g L−1, and a pH of 12, the adsorption of methylene blue dye by GOH/DMCS reached equilibrium after 120 min, and the maximum adsorption amount was 205.34 mg·g−1. The adsorbent was then cycled eight times to test its reusability, and the adsorption efficiency remained greater than 86%. The adsorption process of methylene blue by GOH/DMCS fit well to a pseudo second-order kinetic model. These results showed that the adsorption rate was more sensitive to the initial concentration of methylene blue dye, which implies a chemical adsorption process. The adsorption process conformed to the Langmuir isotherm adsorption model, indicating that the adsorption was monolayer surface adsorption.

A Novel "Turn on" Chemiluminescence Aptasensor for Alpha Fetoprotein Detection Based on Oligonucleotide Chain Functionalized Magnetic Graphene Oxide and Co-Catalyzed Copper-Based Organic Framework Composites

A Novel "Turn on" Chemiluminescence Aptasensor for Alpha Fetoprotein Detection Based on Oligonucleotide Chain Functionalized Magnetic Graphene Oxide and Co-Catalyzed Copper-Based Organic Framework Composites

Highly efficient recovery of heavy rare earth elements by using an amino-functionalized magnetic graphene oxide with acid and base resistance

In the application of various magnetic materials for water treatment, control of surface resistance to acid and alkali corrosion remains largely overlooked, which could greatly extend their service life. We herein prepare amino grafted magnetic graphene oxide composites using a simple one-step cross-link reaction between the graphene oxide and magnetic Fe3O4/C nanoparticles. The as-prepared magnetic graphene oxide composites have long-term stability under acid and alkali solutions and shows an excellent performance in removing Ho(III), a representative rare earth element (REE) from water. The observed adsorption capacity of 72.1 mg Ho(III)/g exceeded that of most magnetic materials previously reported. Regeneration of the magnetic composites was realized in acid and alkali solutions but their structural integrity and physicochemical properties retained even after 18 adsorption-desorption cycles. The current adsorbent also shows excellent adsorption performance for other heavy REEs, such as Er(III), Eu(III), Lu(III), Tm(III), Y(III) and Yb(III). This work can provide a new strategy for constructing an acid and base resistance magnetic graphene oxide for the high-efficient recovery of heavy REEs from aqueous solution.

Facile Synthesis of Antibody-Coupled Polydopamine-Coated Magnetic Graphene Oxide Composites for Efficient Immunopurification and Metabolomics Analysis of Mitochondria.

As a vital hub, a mitochondrion houses metabolic pathways that play important roles in cellular physiology. Aberrant metabolites occurring in mitochondria are closely associated with the emergence and progression of various mitochondria-related diseases. Therefore, a simple and versatile approach to efficiently purify intact mitochondria is urgently needed to precisely and comprehensively characterize the composition and abundance of the mitochondrial metabolome in different physiological and pathological states. In this work, novel immunoaffinitive magnetic composites MagG@PD@Avidin@TOM20 were prepared to achieve highly selective isolation of intact mitochondria from three different hepatocytes (LO2, HepG2, and Huh7). The prepared composites inherit combined merits, including strong magnetic responsiveness, excellent stability, and specific and high affinity between antibody TOM20 and mitochondrial outer membrane protein. These mitochondria attached on MagG@PD@Avidin@TOM20 were characterized by the western blot and fluorescence microscopy to confirm their purity and integrity, which are vital for reliable mitochondrial metabolic analysis. Subsequently, ultrahigh-performance liquid chromatography-high-resolution mass spectrometry-based untargeted metabolomics analysis was conducted to characterize the metabolomes in the immunopurified mitochondria and whole cells. Notably, the metabolite profiles of whole cells and mitochondria including itaconic acid, acetylcarnitine, malic acid, etc., were significantly different. These data underscore the importance of determining metabolites at the mitochondrial level, which would supplement us new knowledge at the subcellular level.

Synthesis of Zn metal–organic framework doped magnetic graphene oxide for preconcentration and extraction of cefixime followed by its measurement using HPLC

In this work, an attempt was made to develop a powerful method for the determination of cefixime, as a widely used cephalosporin antibiotic. The method was based on the facile extraction and preconcentration of cefixime using Zn metal–organic framework doped magnetic graphene oxide composite (ZnMOF@MGO), followed by its determination using high-performance liquid chromatography (HPLC). The high surface area, great stability, and distinct features of the new adsorbent made it ideal for very efficient interactions with analyte molecules. ZnMOF@MGO was able to effectively extract cefixime from the complex matrix of real samples. Furthermore, the application of the magnetic-solid phase extraction (MSPE) process provided a low-cost and simple extraction process with a reduced extraction time. The combination of a high-performance extraction with a potent HPLC system resulted in a highly sensitive and selective analytical detection method. The method was able to detect cefixime in a linear range of 0.5–130 ng mL−1, with a detection limit of 0.11 ng mL−1, no important interfering effect was caused by other examined drugs. It was examined for the analysis of cefixime content of pharmaceutical and biological samples and acceptable recovery values were obtained.

Magnetic graphene oxide prepared via ammonia coprecipitation method: The effects of preserved functional groups on adsorption property

Chromium (Cr) has become one of the main pollutants in tannery wastewater, which causes great harm to human health and environment, especially after being oxidized. Herein, the magnetic graphene oxide composite (GO/Fe3O4) is synthesized via coprecipitation method with NH3·H2O. In this way, the self-functional group of graphene oxide (GO) are greatly reserved when Fe3O4 nanoparticles grown on GO sheets, confirming by characterizations, including Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy and Raman. Up to 90% Cr3+ could be adsorbed by resulted GO/Fe3O4 within 140 min, and the maximum adsorption capacity is 279.62 mg g−1. Furthermore, Cr3+ is mainly absorbed by chemical adsorption, according with quasi-second-order kinetic model and Langmuir isotherm. Most importantly, the external magnetic field can effectively recycle the adsorbents from the aqueous solution, facilitating its application in large-scale treatment of tannery wastewater.

A Novel Fe3O4/Graphene Oxide Composite Prepared by Click Chemistry for High-Efficiency Removal of Congo Red from Water

In this paper, a magnetic graphene oxide (MGO) composite was prepared by the click reaction between the alkyne-modified Fe3O4 nanoparticles and the azide-modified graphene oxide for the purpose of removing the Congo red (CR) dye from water. The deposition of the Fe3O4 nanoparticles on the graphene oxide to successfully prepare the MGO composite was evidenced by the Fourier-transform infrared spectrometer, wide-angle X-ray diffraction equipment, scanning electron microscope, thermal gravimetric analyzer, and Raman spectrometer. The value of saturation magnetization for the MGO composite was 34.9 emu/g. The CR absorption capacities of the MGO composite increased first and then decreased as the pH value increased. It was found that the maximum adsorption capacity of the MGO composite for the CR was as high as 769.2 mg/g. In the absorption-desorption experiment, the CR absorption capacities of the MGO composite from the second cycle to the fifth cycle remained stable to be about 130 mg/g. Moreover, both the Langmuir model for the adsorption isotherm and the pseudo-second-order kinetic model could be used to describe the CR absorption behaviors of the MGO composite.

Preparation of magnetic β-cyclodextrin ionic liquid composite material with different ionic liquid functional group substitution contents and evaluation of adsorption performance for anionic dyes

In this study, we successfully prepared two magnetic graphene oxide composites, specifically (mGO@ILs(1)-βCD and mGO@ILs(2)-βCD), with different ionic liquid functional group substitution contents on the β-cyclodextrin (β-CD). Structural characterization of the composite material was performed using Fourier transform infrared spectroscopy, X-ray diffraction, field emission scanning electron microscopy, specific surface area and pore volume measurements. Comparison of the adsorption performance of the two materials for anionic dyes (lemon yellow (LY), sunset yellow (SY), and ponceau 4R (P4R)) in simulated wastewater. Effect of initial pH value, contact time were studied and discussed in terms of affinity and adsorption efficiency. The adsorption of the anionic azo dye by two adsorbent followed Langmuir adsorption isotherm models and pseudo-second-order kinetics. Noticeably, the maximum adsorption capacity based on the Langmuir model showed that mGO@ILs(2)-βCD was better than mGO@ILs(1)-βCD. Additionally, the adsorbent maintains excellent adsorption capacity after five cycles of adsorption-desorption and has remarkable selective separability. The results showed that the high-density substitution content of the ionic liquid functional groups on β-cyclodextrin in mGO@ILs(2)-βCD is helpful to improve the adsorption capacity and efficiency.

Simultaneous extraction and preconcentration of three beta (β)-blockers in biological samples with an efficient magnetic dispersive micro-solid phase extraction procedure employing in situ sorbent modification

A straightforward and sensitive magnetic dispersive micro-solid phase extraction based on in situ sorbent modification in sample solution was developed for the simultaneous extraction of metoprolol, atenolol, and propranolol (three beta-blockers) in human plasma and urine samples. To prepare a suitable sorbent, magnetic graphene oxide as a magnetic core was synthesized and modified with sodium dodecyl sulfate in the sample solution containing the analytes. In the procedure, the sorbent synthesis and the analyte extraction were simultaneously performed in the sample solution, which leads to a reduction in the time and cost of the determination of the analytes. Three surfactants such as cetyltrimethylammonium bromide, triton X100, and sodium dodecyl sulfate were utilized to modify the magnetic graphene oxide composites and their effects on the extraction of beta-blockers were investigated. The effective variables in the microextraction process of the analytes were optimized based on a design of experiment strategy. Under the optimal conditions, the dynamic ranges of linear were 5–10000, 50–5000, and 10–5000 ng mL–1 with method detection limits of 0.8, 10, and 2 ng mL– 1 for Atenolol, Metoprolol, and Propranolol, respectively The relative standard deviations of the intra-day and inter-day were less than 2.96% and 5.35% (n = 5) for the determination of the analytes, respectively. A suitable enrichment factors of 14, 16, and 18 were obtained for the determination of metoprolol, atenolol, and propranolol, respectively. Finally, the suggested method was successfully applied to measure the beta-blockers in several plasma and urine samples of healthy volunteers without taking drugs and patient volunteers with taking drugs. The method shows suitable relative recoveries in the ranges of 82.4–109.4% and 77.6–95.9% for the analysis of urine and plasma samples with relative standard deviations between 3.1 and 6.7% for the determination of all analytes, respectively.

Rational Synthesis of Aptamer-Functionalized Polyethylenimine-Modified Magnetic Graphene Oxide Composites for Highly Efficient Enrichment and Comprehensive Metabolomics Analysis of Exosomes.

Exosomes, which are phospholipid bilayer nanovesicles, can transfer their content to recipient cells, playing a crucial role in intercellular communication. Exosomes have emerged as promising cancer biomarkers. However, a convenient, efficient, and economical approach for their isolation and comprehensive analysis is still technically challenging. In this study, aptamer-based immunoaffinitive magnetic composites, MagG@PEI@DSP@aptamer, were prepared to achieve the convenient capture, efficient enrichment, and mild release of exosomes. The constructed composites contain three segments: a PEI-modified magnetic graphene scaffold, an aptamer CD63 sequence, and a cleavable cross-linker in between. Notably, the binding capacity of MagG@PEI@DSP for an aptamer is 93 nmol/mg, and per milligram MagG@PEI@DSP@aptamer could capture 450 μg exosomes. Moreover, the released exosomes from MagG@PEI@DSP@aptamer composites were intact and well-dispersed. The prepared composites were then applied to profile the metabolite composition of exosomes secreted by breast cancer cells MCF-7, and the number of detected features was obviously increased when compared to that obtained by the traditional ultracentrifugation method (4528 vs 3710 and 3967 vs 3785 in the positive and negative ionization modes). Besides, the exosomes secreted by MCF-7 and normal breast cells MCF-10A were isolated from cell culture medium with MagG@PEI@DSP@aptamer, and their metabolic profiles were then comprehensively analyzed; in total, 119 metabolites in MCF-7 and MCF-10A were identified. Compared with exosomes from MCF-10A, 43 and 42 metabolites were upregulated and downregulated, respectively, in those from MCF-7. These data showed that the prepared MagG@PEI@DSP@aptamer composites can be used to effectively capture exosomes and further for metabolomics analysis.

Optimization of Cadmium Adsorption by Magnetic Graphene Oxide Using a Fractional Factorial Design.

Graphene materials have attracted increasing interest in water remediation. In this study, magnetic graphene oxide (MGO) was prepared through the modified Hummers method and the adsorption behaviors of cadmium were investigated. Firstly, the sorption kinetics, isotherms, as well as the effects of pH were investigated. Then, fractional factorial design (FFD) was used to optimize the effects of pH, temperature, time, initial concentration of cadmium ion and NaCl on cadmium adsorption. The results indicate that MGO could effectively remove cadmium ions from an aqueous solution and the sorption data could be described well by pseudo-second-order and Freundlich models, showing that the adsorption rate of cadmium ions on MGO is multilayer adsorption and dominated by the chemical adsorption. According to the FFD results, the maximum adsorption capacity of cadmium ions was 13.169 mg/g under the optimum condition of pH value 8, 45 °C, contact time 60 min, initial cadmium concentration of 70 mg/L and NaCl concentration of 100 mg/L. Higher levels of the pH value, temperature and initial cadmium concentration are beneficial to the adsorption process. These results are important for estimating and optimizing the removal of metal ions by MGO composite.

Adsorption of dichromate ions from aqueous solution onto magnetic graphene oxide modified by β-cyclodextrin.

In this work, the β-cyclodextrin modified magnetic graphene oxide (β-CD/MGO) composite was fabricated by the in situ co-precipitation method and characterized by Fourier transform-infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), vibrating sample magnetometer (VSM), and particle size analysis. The adsorption behavior of dichromate ions on the β-CD/MGO was investigated, and the mechanism of adsorption was also studied using FT-IR and XPS. The results from SEM and TEM showed that the graphene oxide (GO) layer became rough, and many fine particles were attached after compounding with ferroferric oxide and β-cyclodextrin. The characterization results of FT-IR and XPS show that that β-cyclodextrin and ferroferric oxide have been perfectly compounded to the graphene oxide layer and β-CD/MGO has a particle size of about 460nm, a specific surface area of 252.3 m2g-1, and a saturation magnetization of 73.5emug-1. The adsorption amount of dichromate ions on the β-CD/MGO is affected by pH, adsorbent dosage, and adsorption time. Kinetic studies showed that the adsorption process followed a pseudo-second-order kinetic model. Equilibrium data agreed very well with the Langmuir model, the maximum adsorption amount of dichromate ions on the β-CD/MGO was 49.95mgg-1. After five successive adsorbent reuses, the reuse rate is still 73%, indicating the excellent potential reusability of β-CD/MGO adsorbent. β-CD/MGO exhibits excellent adsorption performance for dichromate ions. As an environmentally friendly magnetic adsorbent, β-CD/MGO is suitable for the treatment of dichromate-containing wastewater.