Department of Chemical and Biological Engineering, University of British Columbia, 2360 East Mall, Vancouver, BC V6T 1Z3, Canada.
J Hazard Mater. 2020 Jan 5;381:120921. doi: 10.1016/j.jhazmat.2019.120921. Epub 2019 Jul 24.
This study investigated the capability of ultraviolet radiation at 254 nm and 185 nm (UV/VUV) to degrade cyanotoxin microcystin-LR (MC-LR). Results showed 70% toxin reduction solely by 254 nm direct photolysis (ε = 13,225 ± 814 Mcm; Φ = 0.29 ± 0.03 mol/Einstein). The addition of 185 nm increased MC-LR degradation through advanced oxidation by OH (k = 2.25 ± 0.39 × 10 Ms). Alkalinity and organics (DOC) reduced MC-LR degradation by scavenging OH (k = 0.117 cm/mJ; k = 0.0497 cm/mJ; k = 0.019 cm/mJ). Chloride absorbed 185 nm, impacting OH formation and generating Cl, while also scavenging OH. However, Cl is reactive and OH scavenging is reversible, resulting in relatively low impact on MC-LR degradation (k = 0.0939 cm/mJ). In natural water, MC-LR could be degraded from a typical concentration (˜15 μg/L) to below detection (<0.5 μg/L) with a UV fluence of 200 mJ/cm using UV/VUV. The presence of cyanobacterial cells impeded MC-LR degradation; however, 90% MC-LR degradation could still be achieved. UV/VUV is a promising chemical-free technology capable of MC-LR degradation in a variety of water conditions, and a potentially suitable treatment option for small, remote communities.
本研究考察了 254nm 和 185nm（UV/VUV）紫外线辐射降解微囊藻毒素 MC-LR 的能力。结果表明，仅通过 254nm 直接光解就可实现 70%的毒素去除（ε=13225±814 Mcm；Φ=0.29±0.03 mol/爱因斯坦）。185nm 的添加通过 OH 的高级氧化作用进一步提高了 MC-LR 的降解效率（k=2.25±0.39×10 Ms）。碱度和有机物（DOC）通过清除 OH 降低了 MC-LR 的降解效率（k=0.117 cm/mJ；k=0.0497 cm/mJ；k=0.019 cm/mJ）。氯离子吸收 185nm 光，影响 OH 的生成并生成 Cl，同时也清除 OH。然而，Cl 是反应性的，而 OH 清除是可逆的，因此对 MC-LR 降解的影响相对较低（k=0.0939 cm/mJ）。在天然水中，使用 UV/VUV，UV 剂量为 200mJ/cm 时，MC-LR 可从典型浓度（˜15μg/L）降解至低于检测限（<0.5μg/L）。蓝藻细胞的存在会阻碍 MC-LR 的降解；然而，仍可实现 90%的 MC-LR 降解。UV/VUV 是一种有前途的无化学试剂技术，可在多种水质条件下降解 MC-LR，并且可能是小型、偏远社区的一种合适的处理选择。
