Abstract:

The degradation features of high-concentration atrazine（ATZ），sulfamethoxazole（SMX） and metoprolol（MET） in a flow-through UV/chlorine reactor under different water matrices was investigated. The results showed that the degradation processes could be well fitted by the pseudo-first-order kinetics（R²≥0.97） with the order of rate constants following SMX>MET>ATZ. The low UV transmittance of the reaction solutions and the limited extent of mixing in the flow-through reactor resulted in poor applicability of the steady-state approximation model in predicting the degradation rates of the contaminants. Compared with in deionized water，the degradation rate of ATZ in tap water was slightly decreased，while those of SMX and MET were increased significantly. It could be obtained from the analysis of individual water matrix that，the reason for the latter is that the generation of ClO· and CO₃^·- was promoted respectively with Cl^- and HCO₃^-，while the UV photolysis-dominated degradation pathway of ATZ made it less affected. The electrical energy per order（E_EO） results implied that the energy consumption in real water was expected to be further reduced by increasing the oxidant concentration appropriately. Considering the generation of disinfection by-products and toxicity assessment，future research needed to focus on the degradation efficiency of ATZ itself and the generation of trichloromethane during the degradation of MET.

Key words: UV/chlorine, flow-through, water matrix, energy consumption, toxicity assessment

摘要：

考察了过流式紫外/氯反应器中高浓度阿特拉津（ATZ）、磺胺甲恶唑（SMX）和美托洛尔（MET）在不同水质背景下的降解特征。结果表明：3种目标污染物在过流式紫外/氯反应器中的降解均符合准一级反应动力学模型（R²≥0.97），且各污染物按反应速率常数大小排序为SMX＞MET＞ATZ。反应溶液较低的透光性以及过流模式有限的混合程度导致稳态假设模型在预测上述污染物降解时适用性较差。与在去离子水背景下相比，ATZ在自来水中的降解被略微抑制，而SMX与MET的降解得到促进。通过分析不同背景基质的影响可知，后者降解速率提升的原因在于水中共存的Cl^-和HCO₃^-分别提高了反应体系中ClO·与CO₃^·-的浓度，而ATZ因以UV光解为主受到的影响可忽略。单位电能消耗（E_EO）表明，适当提高氧化剂浓度有望进一步降低实际水体中污染物降解所需能耗。综合考虑反应消毒副产物的生成情况和毒性评估结果，后续研究需要重点关注ATZ本身的降解效率以及MET降解过程中三氯甲烷的生成。

关键词: 紫外/氯工艺, 过流式, 水质背景, 能耗, 毒性评估

CLC Number: 

• X703.1