氯消毒中有机防晒剂BP9的去除转化与风险评价

Removal,transformation and risk assessment of UV-filter BP9 during chlorination disinfection

对典型有机防晒剂二苯甲酮-9(BP9)在氯消毒过程中的氧化反应进行研究,考察BP9初始浓度、余氯初始浓度、溶液p H值和氨氮浓度对反应的影响,探究BP9氯氧化降解机理,评估其生态风险.结果表明,在BP9初始浓度5mg/L、余氯初始浓度5mg/L的条件下,90s内BP9去除率达到91.3%,符合准一级反应动力学.降解速率常数随着BP9初始浓度及氨氮浓度增加而减小,随余氯初始浓度增大而增大,中性条件下有利于BP9氯氧化反应.基于HPLC-MS/MS和GC-MS解析出7种中间产物,提出可能降解路径.发光细菌毒性分析和ECOSAR预测均表明,BP9氯氧化反应生成了比母物质毒性更高的中间产物,对饮用水水质安全造成潜在风险.

The issue of new disinfection by-products in drinking water is attracting increasing concern. Chlorination of atypical UV-filter benzophenone-9 （BP9） was studied. The effect of initial BP9 concentration, initial residual chlorine, pHvalue, and ammonia nitrogen concentration on the reaction were also investigated. The degradation mechanism and theecological risk were further discussed. The results indicated that, BP9 removal could reach 91.3% in 90s under theconditions of initial BP9 concentration 5mg/L, initial residual chlorine 5mg/L. BP9 chlorination process obeyed thepseudo-first-order kinetics. The degradation rate decreased with the increase of initial BP9 concentration and ammonianitrogen concentration, while increased with the increase of initial residual chlorine. Neutral conditions are favorable forBP9 chlorination. Seven intermediates were identified by HPLC-MS/MS and GC-MS, and possible degradation pathwayswere also proposed. Luminescent bacteria experiment and ECOSAR prediction both showed that intermediates producedin BP9 chlorination have higher toxicity than the parent compound, which pose a potential risk to drinking water safety.