pH significantly affects removal of trace antibiotics in chlorination of municipal wastewater
- 作者：Bing Li libing0925@126.com ; Tong Zhang ; zhangt@hkucc.hku.hk ; zhangt@hku.hk
- 关键词：Antibiotics ; Free available chlorine ; Kinetics ; Sewage treatment plant
- 刊名：Water Research
- 出版年：2012
- 期刊代码：57_00431354
- 类别：civ
- 出版时间：July, 2012
- 卷：46
- 期：11
- 页码：3703-3713
- 文件大小：683 K
摘要
The effect of pH on chlorination behaviors of 12 antibiotics, including 尾-lactams, sulfonamides, fluoroquinolones, tetracyclines, macrolides, and others at environmentally relevant concentrations was systematically examined in the effluent matrix of activated sludge process. The removal of most antibiotics (except cefalexin and tetracycline) significantly depended on pH in the range of 5.5-8.5. The elimination rates of ciprofloxacin, norfloxacin, anhydro-erythromycin, and roxithromycin increased while that of sulfamethoxazole decreased significantly with the increase of pH. Sulfadiazine, ofloxacin, and trimethoprim exhibited the highest reactivity with free available chlorine under the pH of 6-7, 7, and 7.5, respectively. Not only the free available chlorine species (HOCl and OCl鈭?/sup>), but also the antibiotics species (cationic, neutral and anionic) affected the overall reaction rate. Anionic antibiotic species are usually much more reactive (1-3 orders of magnitude greater) than cationic antibiotic species toward free available chlorine. Although OCl鈭?/sup> is a weaker oxidant than HOCl, chlorination of sulfadiazine, sulfamethoxazole, ciprofloxacin, norfloxacin, and trimethoprim with OCl鈭?/sup> became significant at pH > 7.5. The observed kinetics rate constants calculated from species-specific rate constants could accurately (0.91 < R2 < 0.99) predict the antibiotic removal in chlorination of activated sludge effluent with similar DOC and ammonia concentration to this study at a given pH value.