Martin Jeffrey Thomas, Chai Tia, Leshuk Timothy Michael Carter, Young Zachary William, Gu Frank
H2nanO Inc., Kitchener, ON N2G 1H6, Canada E-mail:
Water Sci Technol. 2023 Mar;87(5):1250-1258. doi: 10.2166/wst.2023.037.
Biological selenium reduction processes are commonly employed as the best available technology (BAT) for selenium removal; however, as a by-product they produce trace amounts of organoselenium compounds with orders of magnitude greater bioaccumulation potential and toxicity. Here, we assessed buoyant photocatalysts (BPCs) as a potential passive advanced oxidation process (P-AOP) for organoselenium treatment. Using a synthetic mine-impacted water solution, spiked with selenomethionine (96 μg/L) as a representative organoselenium compound, photocatalysis with BPCs fully eliminated selenomethionine to <0.01 μg/L with conversion to selenite and selenate. A theoretical reaction pathway was inferred, and a kinetics model developed to describe the treatment trends and intermediates. Given the known toxic responses of Lepomis macrochirus and Daphnia magna to organoselenium, it was estimated that photocatalysis could effectively eliminate organoselenium acute toxicity within a UV dose of 8 kJ/L (1-2 days solar equivalent exposure), by transformation of selenomethionine to less hazardous oxidized Se species. Solar photocatalysis may therefore be a promising passive treatment technology for selenium-impacted mine water management.
生物硒还原工艺通常被用作去除硒的最佳可行技术（BAT）；然而，作为副产品，它们会产生痕量的有机硒化合物，其生物累积潜力和毒性要高出几个数量级。在此，我们评估了漂浮光催化剂（BPCs）作为处理有机硒的潜在被动高级氧化工艺（P-AOP）。使用一种合成的受矿山影响的水溶液，加入硒代蛋氨酸（96 μg/L）作为代表性有机硒化合物，BPCs光催化将硒代蛋氨酸完全去除至<0.01 μg/L，并转化为亚硒酸盐和硒酸盐。推断了一条理论反应途径，并建立了一个动力学模型来描述处理趋势和中间产物。鉴于已知大鳍鳞鳃太阳鱼和大型溞对有机硒的毒性反应，据估计，通过将硒代蛋氨酸转化为危害较小的氧化态硒物种，光催化可在8 kJ/L的紫外线剂量（相当于1 - 2天的日照）内有效消除有机硒的急性毒性。因此，太阳能光催化可能是一种用于管理受硒影响的矿井水的有前景的被动处理技术。
