Novel Biosynthesis of Graphene-Supported Zero-Valent Iron Nanohybrid for Efficient Decolorization of Acid and Basic Dyes

Abstract

Herein, respiratory nitrate reductases (NAR) were utilized in the biosynthesis of zero-valent iron (ZVI) graphene nanocomposite as a simultaneous reducing and capping agent, for the first time, to efficiently adsorb methylene blue (MB) and direct red-81 (DR-81). Under anaerobic conditions, the greenly synthesized graphene was incubated with iron precursor in the presence of crude-NAR enzyme for 48 h to obtain the ZVI graphene composite followed by characterizing this composite using physiochemical analyses. Scanning and transmission electron microscopy, energy dispersive X-ray spectroscopy and X-ray diffraction techniques assured the chemical composition and the interaction between ZVI and graphene. The influences of operating conditions such as contact time, pH and adsorbent dose on the adsorption efficacy were explored in the case of ZVI graphene, graphene and ZVI. ZVI graphene nanocomposite displayed the highest removal efficiency of MB and DR-81 compared to graphene and ZVI-NPs. The removal percentages of DR-81 and MB by ZVI graphene nanocomposites were 88.3 ± 2.66% and 87.6 ± 2.1%, respectively, at pH 7, adsorbent dose 20 mg/50 mL, initial MB or DR-81 concentration of 10 mg/L and shaking speed of 150 rpm. A pseudo first-order model could describe the adsorption kinetics, and the adsorption mechanism was discussed. The promising results of the current study support the potential of the recruitment of ZVI graphene nanocomposites in eliminating various pollutants from industrial effluents on a larger scale. Further, the prepared nanohybrid can be used in other applications such as photocatalysis, Fenton and persulfate activation processes.

Novel Approach to Photocatalytic Removal of Linezolid by Advanced Nano-Biochar/Bismuth Oxychloride Hybrid

“…By prolonging the time was prolonged to 4.5 h, the removal performance was nearly unchanged. The suppression of the removal rate after 3.5 h was due to the loss of biochar particles during the withdrawal of the samples, which reduced the adsorption sites and metal oxides that could adsorb LIN molecules and generate reactive species prior to the illumination by solar light, respectively. , Further, increasing the reaction time could contribute to reducing the binding sites and active sites that are in charge of adsorbing and degrading LIN molecules owing to the accumulation of LIN molecules and their intermediates on the surface . Thus, extending the time to 4.5 h just increased the removal ratios by 0.45, 1.81, and 0.5% in the case of COD, TOC, and LIN, respectively.…”

A novel Corchorus olitorius-derived biochar/Bi 12 O 17 Cl 2 photocatalyst for decontamination of antibiotic wastewater containing tetracycline under natural visible light

“…Figure (5a) shows the removal of TC and the concentration of the generated intermediates over 6 h using 100 mg/L of the prepared biochar at pH 4.7±0.5, initial TC concentration of 163 mg/L and COD of 1244 mg/L. The removal efficiencies of tetracycline and COD were 37% and 48.15%, respectively after 5 h, whereas they were only 38.2% and 48.4% after 6 h indicating that the optimum contact time was 5 h. After 5 h, the biochar's surface and pores might be saturated by the adsorbed TC molecules 35,36 . Therefore, the removal of TC after 5 h was limited.…”

One-Pot Synthesis of Lamellar Fe-Cu Bimetal-Decorated Reduced Graphene Oxide and Its Enhanced Removal of Cr(VI) from Water

“…Through combining the advantages of nZVI and graphene, composite materials have gained increasing attention for the remediation of aqueous environmental pollution. Various organic and inorganic pollutants have been verified to be effectively removed by ZVI/graphene nanocomposites [19][20][21][22][23]. Graphene oxide (GO) is a versatile graphene-based material with abundant oxygen-containing groups, such as carboxyl, hydroxyl, and epoxy groups, which makes it easier to make surface modifications [24].…”