UV/Cl工艺对三氯生的去除与降解机理研究

Removal and degradation mechanism of triclosan by the UV/chlorine process

对UV/Cl高级氧化工艺降解水中广谱抗菌剂三氯生(TCS)进行研究,对比单一UV、单一Cl和UV/Cl工艺对TCS的去除效果.考察UV光强、余氯初始浓度、溶液pH值和氨氮浓度等因素对反应的影响,探究TCS在UV/Cl工艺中的降解机理,评估其生态风险.结果表明,与单一UV、单一Cl相比,TCS在UV/Cl工艺中降解效果较好,反应符合准一级反应动力学,降解速率常数随UV光强、余氯初始浓度增大而增大,随NH_4^+-N浓度的增加而减小.基于HRMSQ-TOF解析出17种中间产物,提出了降解反应路径.发光细菌毒性分析和ECOSAR预测均表明,TCS在UV/Cl工艺中产生毒性较高的中间产物,随着反应的进行,产生了毒性较低的中间产物,生态环境风险得以减少.

Degradation of triclosan(TCS), a kind of broad-spectrum antimicrobial agent, was studied in water by the UV/chlorine advanced oxidation process. The removal of TCS by single UV, single chlorination and the UV/chlorine process was compared. The effect of different factors on the UV/chlorine process was investigated, including UV intensity, initial residual chlorine, pH value and ammonia concentration. The degradation mechanism and the ecological risk were further discussed. The results indicated that TCS had higher removal by the UV/chlorine process compared with single UV and single chlorination. The reaction fitted pseudo-first-order kinetics. The degradation rate increased with the increase of UV intensity and initial residual chlorine, while decreased with the increase of ammonia concentration. Seventeen intermediates were identified by HRMS Q-TOF, and the possible degradation pathway was also proposed. Both luminescent bacteria experiment and ECOSAR prediction showed that intermediates with high toxicity were produced on TCS degradation by the UV/chlorine process. With the process of reaction, intermediates generated with lower toxicity, and the ecological environment risk was reduced.