Yuan Honghong, Huang Yumeng, Jiang Ouyuan, Huang Yue, Qiu Dongsheng, Gustave Williamson, Tang Xianjin, Li Zhongjian
Zhejiang Provincial Key Laboratory of Agricultural Resources and Environment, College of Environmental and Resource Sciences, Institute of Soil and Water Resources and Environmental Science, Zhejiang University, Hangzhou, China.
ZJU-Hangzhou Global Scientific and Technological Innovation Center, Hangzhou, China.
Front Microbiol. 2022 Mar 11;13:812991. doi: 10.3389/fmicb.2022.812991. eCollection 2022.
Arsenate [As(V)] is a toxic metalloid and has been observed at high concentrations in groundwater globally. In this study, a bioelectrochemical system (BES) was used to efficiently remove As(V) from groundwater, and the mechanisms involved were systematically investigated. Our results showed that As(V) can be efficiently removed in the BES cathode chamber. When a constant cell current of 30 mA ( , volume current density = 66.7 A/m) was applied, 90 ± 3% of total As was removed at neutral pH (7.20-7.50). However, when was absent, the total As in the effluent, mainly As(V), had increased approximately 2-3 times of the As(V) in influent. In the abiotic control reactor, under the same condition, no significant total As or As(V) removal was observed. These results suggest that As(V) removal was mainly ascribed to microbial electrosorption of As(V) in sludge. Moreover, part of As(V) was bioelectrochemically reduced to As(III), and sulfate was also reduced to sulfides [S(-II)] in sludge. The XANES results revealed that the produced As(III) reacted with S(-II) to form AsS, and the residual As(III) was microbially electroadsorbed in sludge. This BES-based technology requires no organic or chemical additive and has a high As(V) removal efficiency, making it an environment-friendly technique for the remediation of As-contaminated groundwater.
砷酸盐[As(V)]是一种有毒类金属，在全球地下水中均检测到其高浓度存在。在本研究中，采用生物电化学系统（BES）从地下水中高效去除As(V)，并对其中涉及的机制进行了系统研究。我们的结果表明，As(V)可在BES阴极室中被高效去除。当施加30 mA的恒定电池电流（ ，体积电流密度 = 66.7 A/m）时，在中性pH值（7.20 - 7.50）条件下，总砷的90±3%被去除。然而，当不存在 时，流出物中的总砷（主要为As(V)）增加至进水As(V)的约2 - 3倍。在非生物对照反应器中，在相同条件下，未观察到总砷或As(V)有显著去除。这些结果表明，As(V)的去除主要归因于污泥中As(V)的微生物电吸附作用。此外，部分As(V)在污泥中被生物电化学还原为As(III)，同时硫酸盐也被还原为硫化物[S(-II)]。XANES结果表明，生成的As(III)与S(-II)反应形成AsS，残余的As(III)则被微生物电吸附在污泥中。这种基于BES的技术无需添加有机或化学添加剂，且具有较高的As(V)去除效率，使其成为一种修复砷污染地下水的环保技术。
