Arsenite removal without thioarsenite formation in a sulfidogenic system driven by sulfur reducing bacteria under acidic conditions.

Autor: Sun J; School of Chemistry & Environment, South China Normal University, Guangzhou, 510631, China., Hong Y; School of Chemistry & Environment, South China Normal University, Guangzhou, 510631, China., Guo J; School of Chemistry & Environment, South China Normal University, Guangzhou, 510631, China., Yang J; School of Chemistry & Environment, South China Normal University, Guangzhou, 510631, China., Huang D; School of Chemistry & Environment, South China Normal University, Guangzhou, 510631, China., Lin Z; School of Chemistry & Environment, South China Normal University, Guangzhou, 510631, China., Jiang F; School of Chemistry & Environment, South China Normal University, Guangzhou, 510631, China; MOE Key Laboratory of Theoretical Chemistry of Environment, South China Normal University, Guangzhou, 510006, China. Electronic address: jiangfeng@scnu.edu.cn.
Jazyk: angličtina
Zdroj: Water research [Water Res] 2019 Mar 15; Vol. 151, pp. 362-370. Date of Electronic Publication: 2018 Dec 27.
DOI: 10.1016/j.watres.2018.12.027
Abstrakt: Sulfidogenic process using sulfate-reducing bacteria (SRB) has been used to remove arsenite from the arsenic-contaminated waters through the precipitation of arsenite with sulfide. However, excessive sulfide production and significant pH increase induced by sulfate reduction result in the formation of the mobile thioarsenite by-products and the inefficiency and instability of arsenite removal, especially when the arsenite level fluctuates. In this study, we proposed a novel sulfidogenic process driven by sulfur reducing bacteria (S 0 RB) for the arsenite removal under acidic conditions. In a long term experiment, efficient sulfide production (0.42 ± 0.2 kg S/m 3 -d) was achieved without changing the acidic condition (pH around 4.3) in a sulfur reduction bio-reactor. With the acidic sulfide-containing effluents from the bio-reactor, over 99% of arsenite (10 mg As/L) in the arsenic-contaminated water was precipitated without the formation of soluble thioarsenite by-products, even in the presence of excessive sulfide. Maintaining the acidic condition (pH around 4.3) of the sulfide-containing effluent was essential to ensure the efficient arsenite precipitation and minimize the formation of thioarsenite by-products when the arsenite to sulfide molar ratios ranged from 0.1 to 0.46. An acid-tolerant S 0 RB, Desulfurella, was found to be responsible for the efficient dissimilatory sulfur reduction under acidic conditions without changing the solution pH significantly. The microbial sulfur reduction may proceed through the direct electron transfer between the S 0 RB and sulfur particles, and also through the indirect electron transport mediated by electron carriers. The findings of this study demonstrate that the proposed sulfidogenic process driven by S 0 RB working under acidic conditions can be a promising alternative to the SRB-based process for arsenite removal from the arsenic-contaminated waters.
(Copyright © 2018 Elsevier Ltd. All rights reserved.)
Databáze: MEDLINE
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