Highly Efficient Antimonate Removal from Water by Pyrite/Hematite Bi-Mineral: Performance and Mechanism Studies

Published on 2019-11-08T19:48:25Z (GMT) by
Pyrite/hematite bi-mineral (FeS<sub>2</sub>/α-Fe<sub>2</sub>O<sub>3</sub>) was obtained by thermal modification of pyrite. FeS<sub>2</sub>/α-Fe<sub>2</sub>O<sub>3</sub> was investigated and developed as a promising adsorbent for antimonate [Sb­(V)] removal. The influence of initial concentration, temperature, initial pH, contact time, and coexisting anions on Sb­(V) adsorption performance of FeS<sub>2</sub>/α-Fe<sub>2</sub>O<sub>3</sub> was investigated. FeS<sub>2</sub>/α-Fe<sub>2</sub>O<sub>3</sub> exhibited good adsorption performance and excellent removal efficiency. The results of the Langmuir isotherm model indicated that FeS<sub>2</sub>/α-Fe<sub>2</sub>O<sub>3</sub> had a large adsorption capacity (347.2 mg/g) for Sb­(V) removal from water. High removal efficiency by FeS<sub>2</sub>/α-Fe<sub>2</sub>O<sub>3</sub> was achieved over a broad pH range (2.5–10.7). The coexisting anions had little influence on Sb­(V) adsorption by FeS<sub>2</sub>/α-Fe<sub>2</sub>O<sub>3</sub>. The pseudo-second-order and Dubinin–Radushkevich model analyses (<i>E</i> = 12.62 kJ/mol) suggested that FeS<sub>2</sub>/α-Fe<sub>2</sub>O<sub>3</sub>’s Sb­(V) removal process was chemisorption. The negative Gibbs free energy change and endothermic enthalpy change of 5.00 kJ/mol indicated that Sb­(V) adsorption by FeS<sub>2</sub>/α-Fe<sub>2</sub>O<sub>3</sub> was feasible, endothermic, and spontaneous. Additionally, Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy analyses indicated that Sb­(V) formed an inner-sphere complex on thiol groups and hydroxyl groups surface sites on the surface of FeS<sub>2</sub>/α-Fe<sub>2</sub>O<sub>3</sub>. At last, the real environmental water application also confirmed the excellent adsorption performance of FeS<sub>2</sub>/α-Fe<sub>2</sub>O<sub>3</sub>. From a practical viewpoint, FeS<sub>2</sub>/α-Fe<sub>2</sub>O<sub>3</sub> can be a hopeful alternative for the remediation of Sb­(V) pollution because of its large uptake capacity, low-cost, reusability, and easy availability.

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He, Xingyu; Min, Xiaobo; Peng, Tianyu; Ke, Yong; Zhao, Feiping; Wang, Yunyan; et al. (2019): Highly Efficient Antimonate Removal from Water by

Pyrite/Hematite Bi-Mineral: Performance and Mechanism Studies. ACS Publications. Collection. https://doi.org/10.1021/acs.jced.9b00801