Adsorption and transformation of thioarsenite at hematite/water interface under anaerobic condition in the presence of sulfide.

Autor: Wang Y; Key Laboratory of Pollution Ecology and Environmental Engineering, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, 110016, China; University of Chinese Academy of Sciences, 19A Yuquan Road, Beijing, 100049, China., Lin J; Key Laboratory of Pollution Ecology and Environmental Engineering, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, 110016, China., Wang S; Key Laboratory of Pollution Ecology and Environmental Engineering, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, 110016, China. Electronic address: wangshaofeng@iae.ac.cn., Zhang D; Key Laboratory of Pollution Ecology and Environmental Engineering, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, 110016, China., Xiao F; Key Laboratory of Pollution Ecology and Environmental Engineering, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, 110016, China; University of Chinese Academy of Sciences, 19A Yuquan Road, Beijing, 100049, China., Wang X; Key Laboratory of Pollution Ecology and Environmental Engineering, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, 110016, China., Jia Y; Key Laboratory of Pollution Ecology and Environmental Engineering, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, 110016, China. Electronic address: yongfeng.jia@iae.ac.cn.
Jazyk: angličtina
Zdroj: Chemosphere [Chemosphere] 2019 May; Vol. 222, pp. 422-430. Date of Electronic Publication: 2019 Jan 28.
DOI: 10.1016/j.chemosphere.2019.01.157
Abstrakt: The adsorption behavior of thioarsenite (TAs III ) on the surface of hematite (α-Fe 2 O 3 ) is unknown at present. In the present study, we have investigated the transformation and reactions of TAs III [monothioarsenite (MTAs III ) and dithioarsneite (DTAs III )] on the surface of α-Fe 2 O 3 in the presence of sulfide at S/As = 1 and 3 by X-ray absorption spectroscopy (XAS) and Raman spectroscopy. The adsorption envelopes reveal that the adsorption of TAs III on α-Fe 2 O 3 is significantly less than that of arsenite (As III ) in the pH range from 7 to 11 with the initial As concentration of 25 mg L -1 . However, at the initial As concentration of 135 mg L -1 , the uptake of TAs III by α-Fe 2 O 3 is higher at pH 7 but lower at pH 8-11 than that of As III . The adsorption isotherms show that the adsorption of As on α-Fe 2 O 3 is largely inhibited by the presence of aqueous sulfide at pH 7 with low As equilibrium concentration (<40 mg L -1 ). Whereas the uptake of As by α-Fe 2 O 3 is highly elevated compared with the value predicted by Langmuir model at pH 7 with high As equilibrium concentration (>40 mg L -1 ), implying the formation of As-bearing (surface) precipitate. The As and S K-edge XAS as well as Raman spectroscopy confirm the formation of As sulfide precipitate on the surface of α-Fe 2 O 3 in MTAs III system. It is worth to note that the oxidation of (thio)As III occurs on the surface of α-Fe 2 O 3 in DTAs III system under strictly anaerobic conditions. These results shed new light on the understanding of the interfacial behavior of As and point to the potential implication in immobilization and removal of arsenic in sulfidic environment.
(Copyright © 2019 Elsevier Ltd. All rights reserved.)
Databáze: MEDLINE
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