MOE Key Lab of Environmental Remediation and Ecosystem Health, College of Environmental and Resource Science, Zhejiang University, Hangzhou, 310058 China.
State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China.
Water Res. 2021 Oct 1;204:117602. doi: 10.1016/j.watres.2021.117602. Epub 2021 Aug 27.
Selenate and sulfide are both contaminants which severely pollute water bodies. Respective bioremediation of selenate- and sulfide-contaminated wastewaters requires abundant electron donors and acceptors. Here, we present a novel concept coupling biological selenate to selenite (shortcut deselenization) and chemical sulfide-driven selenite reduction, to remove multiple pollutants simultaneously. Vial tests showed that shortcut deselenization could save at least two thirds of operation time and one third of carbon source, compared to the complete deselenization to elemental selenium. Subsequent co-removal of sulfide and selenite was optimized at reaction pH of ∼10 and reactant molar ratio of ∼4. Using a newly-designed continuous flow system, >95% removal of both selenate and sulfide was achieved by coupling shortcut deselenization to sulfide oxidation. A series of characterization tools revealed that the final collected precipitates were comprised of high-purity hexagonal selenium (97.4%, wt) and inconsiderable sulfur (2.6%, wt). Superior over selenate-reducing solutions generally producing selenium mixed with reagents or microorganisms, the selenium products generated here were highly purified thus very favorable for further recovery and reuse. Overall, this proof-of-concept study provided a promising technology not only for co-removal of multiple pollutants, but also for substantial costs saving, as well as for valuable products recovery.
硒酸盐和硫化物都是严重污染水体的污染物。分别对受硒酸盐和硫化物污染的废水进行生物修复需要大量的电子供体和受体。在这里，我们提出了一个将生物硒酸盐转化为亚硒酸盐（短程脱硫）和化学硫化物驱动的亚硒酸盐还原相结合的新概念，以同时去除多种污染物。小瓶试验表明，与完全脱硫到元素硒相比，短程脱硫可至少节省三分之二的运行时间和三分之一的碳源。随后在反应 pH 值约为 10 和反应物摩尔比约为 4 时优化了硫化物和亚硒酸盐的共同去除。使用新设计的连续流动系统，通过将短程脱硫与硫化物氧化相结合，可实现超过 95%的硒酸盐和硫化物去除率。一系列特征化工具表明，最终收集的沉淀物由高纯度的六方硒（97.4%，wt）和少量的硫（2.6%，wt）组成。与通常产生与试剂或微生物混合的硒的硒酸盐还原溶液相比，这里生成的硒产品高度纯净，非常有利于进一步回收和再利用。总的来说，这项概念验证研究不仅为多种污染物的共同去除提供了一种有前景的技术，而且还节省了大量成本，同时还回收了有价值的产品。
