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In this work, magnetic graphene oxide nanocomposites were synthesized by co-precipitation method and used as an adsorbent for removal of arsenic (V) ions from water. The structure and morphology of magnetic graphene oxide nanocomposites were studied by X-ray diffraction, Fourier transform infrared spectroscopy, transmission electron microscopy, Brunauer–Emmett–Teller specific surface area, and vibrating sample magnetometry. Fourier transform infrared spectroscopy, X-ray diffraction, and transmission electron microscopy results of magnetic graphene oxide presented that the Fe3O4 nanoparticles in the size range of 10–25 nm were decorated on graphene oxide nanosheets. The adsorption properties of magnetic graphene oxide nanocomposites for arsenic (V) from water were investigated to study the effects of magnetic graphene oxide mass ratio, contact time, pH, and initial concentration. The suitable magnetic graphene oxide mass ratio of nanocomposites for arsenic (V) adsorption was determined to be 4:1 (FG2). The adsorption process on FG2 followed a pseudo-second-order kinetic and well fitted in to Langmuir isotherm model with the maximum adsorption capacity of 69.44 mg/g at pH 3. Accordingly, FG2 could be used as an effective adsorbent for removal of arsenic (V) from water.

In this study, rice husk ash-silica/graphene oxide (RHA-SiO2/GO) nanocomposites were synthesized by the in situ method using (3-aminopropyl) triethoxysilane as a coupling agent. The obtained produc...

Silica nanoparticles were prepared from rice husk ash (RHA-silica) by precipitation method. The characterization of RHA-silica was studied by X-ray fluorescence, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy, and Brunauer-Emmett-Teller specific surface area. Results showed that RHA-silica was successfully synthesized with a particle size of 5-15 nm and purity of 98.08%. The obtained RHA-silica was applied with different content for fabrication of tubular ceramic-supported poly(vinyl alcohol) membranes using malic acid as a cross-linking agent (RHA-silica/MA-PVA) by dip-coating and solvent evaporation methods. The tubular ceramic-supported RHA-silica/MA-PVA membranes were used for dehydration of 95 wt% ethanol solution by pervaporation (PV) technology. Results indicated membrane with 15 wt% RHA-silica (15RHA-silica/MA-PVA) was suitable for the dehydration with permeate flux of 0.0856 kg/m2·h, separation factor of 46.6, and pervaporation separation index of 3.9 kg/m2h. The tubular ceramic-supported 15RHA-silica/MA-PVA membrane was characterized using XRD, FTIR, scanning electron microscope, differential scanning calorimetry, and contact angle measurement. Results showed that this membrane was 30 μm thick, mechanical stable (swelling rate, 133.9%), hydrophobic (contact angle, 81°), and thermal stable (glass transition temperature, 138.7 °C). Therefore, the tubular ceramic-supported nanocomposite membrane could be considered as a potential alternative for PV dehydration of ethanol.

This study is aimed at studying the adsorption of methylene blue (MB) from aqueous solutions by nickel ferrite/graphene oxide (NGO) nanocomposite. The nanocomposite was characterized by Fourier transform infrared spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, transmission electron microscopy, energy dispersive X-ray, Brunauer-Emmett-Teller-specific surface area, and vibrating sample magnetometer analyses. The interactive effects of critical variables including pH, initial concentration, and contact time on the adsorption capacity of NGO for MB were studied using response surface methodology (RSM) according to composite central design. In RSM models, the predicted values agreed well with verification experiments, with a high correlation coefficient of 0.9887. The adsorption process followed the pseudo-second-order kinetic and Langmuir isotherm models. The maximum capacity for adsorption of MB onto NGO was found to be 476.19 mg/g. Based on these results, NGO has the potential as an efficient adsorbent for the removal of MB from water.

In this study, silver/reduced graphene oxide (Ag/rGO) nanocomposites were synthesized by in situ method with five mass ratios of AgNO3:GO ratio. The characterizations of GO, rGO, silver nanoparticl...

Herein, the surface modification of graphene oxide with silver nanoparticles was examined with the type of reducing agents, the reducing agent:AgNO3 mass ratio, reduction temperature, reduction time, and AgNO3:GO mass ratio. The optimal fabrication condition was determined based on the AgNPs density on GO, AgNPs size, and the antibacterial activity of the Ag/GO by plate colony–counting and optical density methods. The as-prepared materials were analyzed by Fourier transform infrared spectroscopy, X-ray diffraction, Raman spectroscopy, transmission electron microscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, and UV–vis spectroscopy. Results revealed that the appropriate reducing agent is ascorbic acid (AA) with the conditions: the ratio AA:AgNO3 = 1:1; reaction at 40 °C in 10 min with AgNO3:GO ratio of 1.25:1. More than 99.99 % of bacteria was inhibited, with a minimum bactericidal concentration of 50 and 100 µg/mL for P. aeruginosa, and S. aureus, respectively. Furthermore, the materials were surveyed in terms of their interface sorption and sensing applications. The maximum adsorption capacity of the nanocomposite reached 98.04 mg/L at 40–100 mg/L methylene blue, while the limit of detection for detecting Hg(II) in water was indicated to be 223 nM. Therefore, Ag/GO has shown sustainably promising usage for multiple purposes.

Zinc oxide - doped titanium dioxide/reduced graphene oxide (ZnO-TiO2/rGO) nanocomposite was fabricated by the two-step hydrothermal method and used for adsorption and photodegradation of methylene blue in aqueous solution under UV irradiation. The characteristics of the catalyst material were confirmed by Fourier transform infrared spectroscopy, X-ray diffraction, Raman spectroscopy, scanning electron microscope, transmission electron microscopy, energy-dispersive X-ray spectroscopy, Brunauer-Emmett-Teller specific surface area, thermal gravimetric analysis, and UV-vis spectroscopy. The results showed that the presence and uniform distribution of TiO2 and ZnO nanoparticles on the rGO surface with an average diameter of 20 – 30 nm and high specific surface area (182.52 m2/g). The photodegradation was investigated via the pH media. The equilibrium adsorption at pH of 9 achieved the highest adsorption efficiency after 60 min (43.68 %) and 60 min photodegradation (99.84 %). According to the results, the photodegradation using ZnO-TiO2/rGO nanocomposite was stated to be a promising pathway for removing the organic dye from water.

This study aims to prepare in manganese ferrite/graphene oxide (MnFe2O4/GO) nanocomposites for the removal of ibuprofen drug residue from water. The synthesised nanocomposites with various MnFe2O4 content from 30–60 wt.% were characterised by X-ray diffraction, Fourier transform infrared spectroscopy, transmission electron microscopy, vibrating sample magnetometer, Brunauer - Emmett - Teller specific surface area, and energy dispersive X-ray. It was found that the suitable mass ratio of MnFe2O4 in nanocomposite for ibuprofen removal was 50 wt.%. The adsorption process followed the pseudo-second-order kinetic and Langmuir isotherm model. The maximum capacity of MnFe2O4/GO was found to be 156.25 mg g−1. Accordingly, the MnFe2O4/GO could be used as an efficient adsorbent for the removal of ibuprofen from water.

Herein, silver/graphene oxide (Ag/GO) nanocomposite was fabricated by co-precipitation with green reducing agent and then was characterized with modern analytical techniques. The antibacterial activities were conducted via the effects of Ag/GO concentration, time, and pH. Results show that silver nanoparticles were uniformly distributed on the GO sheets nanosized of 17.65 ± 4.76 nm. The antibacterial performance was optimized at pH 5.6, eradicating P. aeruginosa in 180 min at 50 µg/mL Ag/GO concentration and S. aureus in 480 min at 300 µg/mL Ag/GO. This demonstrates the potential of Ag/GO as an antibacterial nanocomposite material.

In this study, silver/graphene oxide (Ag/GO) nanocomposites were synthesized using the in situ method. Glucose was selected as an eco-friendly reducing agent for the reduction of Ag+ into silver nanoparticles (AgNPs). The characterization of GO and Ag/GO with Fourier transform infrared spectroscopy, transmission electron microscopy, X-ray diffraction, Raman spectroscopy, scanning electron microscopye, energy-dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy. Results showed that Ag/GO was successfully synthesized. Silver nanoparticles (AgNPs) with an average size of 17.68 ± 4.48 nm were uniformly distributed onto GO sheets. The antibacterial activity of GO, AgNPs, and Ag/GO were tested against Staphylococcus aureus ATCC 25,923 (S. aureus) and Salmonella enterica ATCC 35,664 (S. enterica) bacteria by optical density and plate colony–counting methods. Test results showed that Ag/GO had higher antibacterial activity than its precursors (bare AgNPs and GO) with a bactericidal rate of more than 99.90 %. Thus, Ag/GO was selected for further experimentation. Simultaneous effects of the interaction time, Ag/GO concentration, pH, annealing temperature, and S. aureus density on the antibacterial activity of Ag/GO were also investigated with full factorial experimental design according to Placket–Burman and Box–Behnken designs. After 10 min of interaction time at 37 °C, the optimal values of these factors were determined to be: Ag/GO concentration of 48 μg/mL, pH 5, and S. aureus density 5.3 × 106 CFU/mL, corresponding to an antibacterial capacity of 99.95 % towards S. aureus. The presented experiment confirmed Ag/GO to be able of eliminating about 99.99 % of S. aureus. All results of the present study affirmed the potential applications of Ag/GO as an antibacterial agent in the medical field.

Nowadays, environmental pollution has increasingly been causing serious issues to human health, especially regards to water pollution. Heavy metals and organic dyes are majorenvironmental pollutants. In this study, manganese ferrite/graphene oxide (MnFe2O4/GO) nanocomposites were fabricated by in situ method and used as an adsorbent for the removal of nickel ions (Ni2+), methylene blue (MB) from water. The MnFe2O4/GO nanocomposite with a mass ratio of MnFe2O4 to GO of 1:1 (FGO2) had high adsorption capacity and was easily separated by external magnetic field. The adsorption data of FGO2 fitted well with a pseudo-second-order kinetic and Langmuir isotherm models. The maximum adsorption capacities of FGO2 for Ni2+ and MB were determined to be 152.67 and 89.29 mg/g, respectively. MnFe2O4/GO nanocomposite was characterized by Fourier transform infrared spectroscopy, X-ray diffraction, transmission electron microscopy, Brunauer-Emmett-Teller (BET) specific surface area, and vibrating sample magnetometer (VSM). FGO2 had the BET specific surface area of 78.46 m2/g and VSM of 28.74 emu/g. Based on these results, the FGO2 could be considered as a highly efficient adsorbent for the removal of Ni2+, MB from water.