Evenly distribution of amorphous iron sulfides on reconstructed Mg-Al hydrotalcites for improving Cr(VI) removal efficiency

• Published in: Chemical Engineering Journal Vol. 417; p. 129228
• Main Authors: Yan, Ruixin, Feng, Xiuping, Kong, Long, Wan, Qun, Zheng, Weilin, Hagio, Takeshi, Ichino, Ryoichi, Cao, Xinde, Li, Liang
• Format: Journal Article
• Language: English; Japanese
• Published: Elsevier B.V 01.08.2021; Elsevier BV
• Subjects: Adsorption; Calcination; FeS/HTs; Hexavalent Chromium; Reduction; FeS/HTs; Calcination; Reduction; Adsorption; Hexavalent Chromium
• ISSN: 1385-8947; 1873-3212
• DOI: 10.1016/j.cej.2021.129228

[Display omitted] •FeS/HTs was synthesized through “calcination-reconstruction-calcination” process.•High-capacity and rapid removal of Cr(VI) were achieved by FeS/HTs.•FeS/HTs exhibited effective Cr(VI) removal in a wide pH range from 3 to 10.•Cr(VI) was removed by adsorption, electrostatic attraction, and chemical reduction. Hexavalent Chromium (Cr(VI)) in water is a public health concern and has been a challenging research subject in environmental field for many years. Herein, a novel composite material consisting of amorphous iron sulfides supported on hydrotalcites (FeS/HTs) was synthesized by “calcination-reconstruction-calcination” process, which enables homogeneous distribution of iron and sulfur on the surface of hydrotalcites (HT). The composite (mass ratio of FeS/HT was 1/2) could effectively remove over 98% of Cr(VI) within 10 min. A pseudo-second-order kinetic model and a Langmuir isotherm model were well fitted the sorption data with a maximum removal capacity of 206.2 mg/g. The superior adsorption capacity of FeS/HTs could be attributed to the combination of the advantages of abundant adsorption sites on HT and powerful reduction properties of iron sulfides. X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) analysis suggested the adsorbed Cr(VI) on the surface and interlayer of FeS/HTs had been reduced to Cr(III) by reductant iron and sulfur. This study demonstrated that FeS/HTs has potential application prospects in Cr(VI) removal.