College of Environmental and Chemical Engineering, Shanghai Engineering Research Center of Energy, Saving in Heat Exchange Systems, Shanghai University of Electric Power, Shanghai 200090, PR China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, PR China.
College of Environmental and Chemical Engineering, Shanghai Engineering Research Center of Energy, Saving in Heat Exchange Systems, Shanghai University of Electric Power, Shanghai 200090, PR China.
J Hazard Mater. 2022 Jun 5;431:128574. doi: 10.1016/j.jhazmat.2022.128574. Epub 2022 Mar 1.
In this study, the degradation kinetic model and pathways of a UV filter, 2-phenylbenzimidazole-5-sulfonic acid (PBSA) during UV/chlorination were investigated. PBSA hardly degraded under UV irradiation or chlorination alone, but its degradation in UV/chlorination was efficient and followed pseudo-first order kinetics at pH 7. Increasing the chlorine dosage from 12.5 to 200 μM can enhance PBSA degradation, while increasing pH from 5 to 9 caused opposite effect. The second-order rate constants between radicals (∙Cl, ∙ClO, and ∙OH) and PBSA and the contribution of ∙OH during UV/chlorination were determined. ∙Cl and ∙OH were confirmed to be the main contributors to PBSA degradation. The presence of background [Formula: see text] and humic acid can inhibit PBSA degradation, but the presence of Cl showed negligible effect. Kinetic model was established, and the prediction correlated well to the experimental results. The mineralization rate in terms of total organic carbon increased with reaction time to 44.9% after 60 min UV/chlorination. The PBSA degradation intermediates in UV/chlorination were identified, and the transformation pathways were proposed accordingly. Furthermore, the formation of chlorinated disinfection by-products (Cl-DBPs) were evaluated in the sequential chlorination for comprehensively evaluation of the efficiency, mechanism, and safety of removing PBSA using UV/chlorination.
在这项研究中，研究了紫外线/氯化过程中一种紫外线滤光剂 2-苯并咪唑-5-磺酸（PBSA）的降解动力学模型和途径。PBSA 在单独的紫外线照射或氯化作用下几乎不会降解，但在紫外线/氯化作用下其降解效率很高，并遵循 pH 值为 7 时的伪一级动力学。增加氯剂量从 12.5 增加到 200 μM 可以增强 PBSA 的降解，而增加 pH 值从 5 增加到 9 则会产生相反的效果。确定了自由基（∙Cl、∙ClO 和 ∙OH）与 PBSA 之间的二级速率常数以及紫外线/氯化过程中 ∙OH 的贡献。确认 ∙Cl 和 ∙OH 是 PBSA 降解的主要贡献者。背景[公式：见文本]和腐殖酸的存在会抑制 PBSA 的降解，但 Cl 的存在几乎没有影响。建立了动力学模型，预测结果与实验结果相关性良好。在 60 分钟紫外线/氯化作用下，总有机碳的矿化率随着反应时间的增加而增加，达到 44.9%。在紫外线/氯化过程中鉴定了 PBSA 的降解中间产物，并相应地提出了转化途径。此外，还评估了连续氯化过程中氯化消毒副产物（Cl-DBPs）的形成，以综合评估使用紫外线/氯化去除 PBSA 的效率、机制和安全性。
