GENOCOV, Department of Chemical, Biological and Environmental Engineering, School of Engineering, Universitat Autònoma de Barcelona, 08193, Bellaterra, Barcelona, Spain.
Advanced Water Management Centre, The University of Queensland, St Lucia QLD 4072, Brisbane, Australia.
Sci Total Environ. 2019 Aug 10;677:175-183. doi: 10.1016/j.scitotenv.2019.04.406. Epub 2019 Apr 29.
Several industrial activities produce wastewater with high sulfate content that can cause significant environmental issues. Although bioelectrochemical systems (BESs) have recently been studied for the treatment of sulfate contained in this wastewater, the recovery of elemental sulfur with BESs is still in its beginnings. This work proposes a new reactor configuration named BES-EC, consisting of the coupling of a BES with an electrochemical cell (EC), to treat this type of wastewater and recover elemental sulfur. The reactor consisted of four electrodes: i) an abiotic anode, ii) a biocathode for the autotrophic sulfate reduction, iii) an anode of an electrochemical cell (EC) for the partial oxidation of sulfide to elemental sulfur (the biocathode and the EC anode were placed in the same chamber) and iv) an abiotic EC cathode. Several cathode potentials and sulfate loads were tested, obtaining high sulfate removal rates (up to 888 mg SO-S L d at -0.9 V vs. SHE with a specific energy consumption of 9.18 ± 0.80 kWh kg SO-S). Exceptionally high theoretical elemental sulfur production rates (up to 498 mg S-S L d) were achieved with the EC controlled at a current density of 2.5 A m. Electron recovery around 80% was observed throughout most of the operation of the integrated system. In addition, short experiments were performed at different current densities, observing that sulfate removal did not increase proportionally to the higher applied current density. However, when the BES was controlled at 30 A m and the EC at 7.5 A m, the proportion of elemental sulfur produced corresponded to 92.9 ± 1.9% of all sulfate removed.
几种工业活动会产生高硫酸盐含量的废水，这可能会导致严重的环境问题。尽管生物电化学系统（BES）最近已被研究用于处理废水中的硫酸盐，但用 BES 回收元素硫仍处于起步阶段。本工作提出了一种新的反应器构型，称为 BES-EC，由 BES 与电化学电池（EC）耦合而成，用于处理这种废水并回收元素硫。该反应器由四个电极组成：i）非生物阳极，ii）用于自养硫酸盐还原的生物阴极，iii）电化学电池（EC）的阳极，用于将硫化物部分氧化为元素硫（生物阴极和 EC 阳极置于同一腔室中）和 iv）非生物 EC 阴极。测试了几种阴极电位和硫酸盐负荷，获得了高的硫酸盐去除率（在 -0.9 V 相对于 SHE 时，最高可达 888 mg SO-S L d，比能耗为 9.18 ± 0.80 kWh kg SO-S）。通过将 EC 控制在 2.5 A m 的电流密度下，可实现极高的理论元素硫产率（最高可达 498 mg S-S L d）。在整个集成系统的大部分运行过程中，观察到电子回收率约为 80%。此外，还在不同的电流密度下进行了短期实验，观察到硫酸盐去除率并没有随施加的电流密度的增加而成比例增加。然而，当 BES 控制在 30 A m 且 EC 控制在 7.5 A m 时，所去除的硫酸盐中约有 92.9 ± 1.9%转化为元素硫。
