ABSTRACT

UV-C and UV-C/peroxydisulfate (PS) treatments of 3,5-dichlorophenol (3,5-DCP), a model industrial pollutant, were comparatively investigated in two different water matrices namely distilled water (DW) and simulated treated urban wastewater (SWW). The treatment performance of the selected treatment processes was comprehensively examined by following changes in 3,5-DCP, dissolved organic carbon (DOC), PS consumption, Cl⁻ release, aromatic/aliphatic degradation products and acute toxicities towards the marine photobacterium Vibrio fischeri and freshwater microalga Pseudokirchneriella subcapitata. The treatability of 2 mg/L (12.3 µM) 3,5-DCP in DW was investigated under different operating conditions such as initial PS concentrations (0.00–1.00 mM) and pH values (3–11) at a fixed light intensity (0.5 W/L). Increasing the pH and PS concentration exhibited positive effects on 3,5-DCP degradation. Even 10 mg/L 3,5-DCP was completely degraded with UV-C/PS treatment in 40 min in the presence of 0.03 mM PS at pH 6.3 accompanied with 95% DOC removal that was achieved after 120 min treatment. The second-order rate constant of 3,5-DCP (10 mg/L) with ${\mathrm{SO}}_4^{\cdot -}$ was determined as 1.77×10⁹ M⁻¹s⁻¹ using competition kinetics. Cl⁻ release and formation of hydroquinone were evidences of 3,5-DCP degradation involving ${\mathrm{SO}}_4^{\cdot -}$. 3,5-DCP (2 mg/L) was also subjected to UV-C and UV-C/PS treatments in SWW. 3,5-DCP (100% after 60 min) and in particular DOC (26% after 120 min treatment) removal efficiencies observed in DW decreased dramatically in SWW. The original and UV-C/PS-treated samples were non-toxic towards Vibrio fischeri; however, Pseudokirchneriella subcapitata toxicity increased from 20% to 47% through 80 min UV-C/PS treatment of 3,5-DCP.

摘要

3,5-二氯苯酚 (3,5-DCP)（一种模型工业污染物）的 UV-C 和 UV-C/过二硫酸盐 (PS) 处理在两种不同的水基质中进行了比较研究，即蒸馏水 (DW) 和模拟处理的城市废水（SWW）。通过跟踪 3,5-DCP、溶解有机碳 (DOC)、PS 消耗、Cl ^-释放、芳香族/脂肪族降解产物以及对海洋光细菌费氏弧菌和淡水微藻Pseudokirchneriella subcapitata. 在固定光强度 (0.5宽/长）。增加 pH 和 PS 浓度对 3,5-DCP 降解表现出积极影响。即使 10 mg/L 3,5-DCP 在 0.03 mM PS 的存在下，pH 6.3 也能在 40 分钟内通过 UV-C/PS 处理完全降解，并在 120 分钟处理后实现 95% 的 DOC 去除。3,5-DCP (10 mg/L) 的二级速率常数与${\mathrm{所以}}_4^{\cdot -}$使用竞争动力学确定为1.77×10 ⁹ M ^-1 s ^-1。Cl ^-释放和对苯二酚的形成是 3,5-DCP 降解的证据，涉及${\mathrm{所以}}_4^{\cdot -}$. 3,5-DCP (2 mg/L) 也在 SWW 中进行了 UV-C 和 UV-C/PS 处理。在 DW 中观察到的 3,5-DCP（60 分钟后 100%）和特别是 DOC（120 分钟处理后 26%）的去除效率在 SWW 中显着降低。原始样品和经 UV-C/PS 处理的样品对费氏弧菌无毒；然而，通过 3,5-DCP 的 UV-C/PS 处理 80 分钟，Pseudokirchneriella subcapitata 的毒性从 20% 增加到 47%。