Document Type : Research Article

Authors

1 Advanced Science Research Center, Japan Atomic Energy Agency, Ibaraki, 319-1195, Japan

2 Water and Environmental Engineering Laboratory, Interdisciplinary Graduate School of Engineering Sciences, Kyushu University, Fukuoka, 816-8580, Japan

3 International Institute for Carbon-Neutral Energy Research (I2CNER), Kyushu University, Fukuoka, 819-0395, Japan

4 Research Center for Negative Emission Technology, International Science Innovation Center, Kyushu University, Fukuoka, 819-0395, Japan

5 Ningyo-toge Environmental Engineering Center, Japan Atomic Energy Agency, Tomata, Okayama, 708-0698, Japan

Abstract

For several decades, arsenic (As) contamination of water was considered as an issue of great concern. In this study, magnesium hydroxide coated iron nanoparticles (nFe0@Mg(OH)2) were developed for enhancing arsenic removal from aqueous solutions. Several parameters were investigated, including Mg/Fe coating ratio, nFe0@Mg(OH)2 dosage, initial pH, reaction temperature, and initial As(V) concentration. The characteristics of the synthesized materials were studied using different techniques, such as transmission electron microscopy (TEM), X-ray diffraction (XRD), and X-ray absorption near edge structure (XANES). Results indicated the superiority of the highest Mg/Fe coating ratio (100%) to the other lower ratios in As(V) removal, corresponding to the adsorption contribution of Mg(OH)2 coating shell. Furthermore, nFe0@Mg(OH)2-100% could efficiently achieve around 100 % final As(V) removal efficiency at wide pH and temperature ranges (3.0 – 9.0, and 25 – 75 oC), at a low dosage of 0.5 g/L, reflecting the high applicability of the proposed material. Mg(OH)2 coating enhanced the anti-aggregation effect of the magnetic nanoparticles, which was confirmed by TEM measurements. Kinetics, thermodynamic, and isotherm analyses depicted that pseudo-second-order was the best model to describe the kinetics data, the endothermic nature of the reaction, and a maximum Sips sorption capacity of 89.97 mg/g (following Sips isotherm model), respectively.

Graphical Abstract

Enhanced Arsenic Removal from Aqueous Solutions Via Magnesium Hydroxide Coated Iron Nanoparticles

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