Research Group EnVOC, Ghent University, Coupure Links 653, Ghent, Belgium.
Chemosphere. 2010 Feb;78(9):1142-7. doi: 10.1016/j.chemosphere.2009.12.026. Epub 2010 Jan 13.
The ozonation of ciprofloxacin was studied in hospital wastewater treatment plant effluent with focus on parent compound degradation, degradation product identification and residual antibacterial activity. Before ozonation, ciprofloxacin sorption on suspended solids was tested as a function of temperature (10.0-27.5 degrees C) and pH (3, 7 and 10). Temperature did not significantly affect ciprofloxacin sorption while sorption was highest at pH 7 (logK(d)=4.7) compared to pH 3 (logK(d)=4.3) and 10 (logK(d)=3.9) (n=3). Ozonation was slowest at pH 7 with ciprofloxacin half life times of 29 min, compared to 19 and 27 min at pH 10 and 3, respectively. Addition of 10-1000 microM H(2)O(2) increased ciprofloxacin half life times up to 38 min, probably influenced by competition with H(2)O(2) for ozone as well as radical species. Ciprofloxacin ozonation products were identical as previously detected during ciprofloxacin ozonation in deionized water and revealed strong pH dependence. Residual antibacterial activity was measured by agar diffusion tests. For Pseudomonas fluorescens and Escherichia coli, reduction of antibacterial activity was related to the parent compound degradation, while degradation products indicated to be the main compounds with respect to the antibacterial activity against Bacillus coagulans.
本研究以医院污水处理厂出水中的环丙沙星为目标污染物，考察了其臭氧化降解过程，包括母体化合物的降解、降解产物的鉴定及剩余抗菌活性。臭氧化前，考察了温度（10.0-27.5°C）和 pH 值（3、7 和 10）对悬浮固体吸附环丙沙星的影响。结果表明，温度对环丙沙星的吸附没有显著影响，而在 pH 值为 7 时的吸附量最大（logK(d)=4.7），明显高于 pH 值为 3（logK(d)=4.3）和 10（logK(d)=3.9）时的吸附量（n=3）。pH 值为 7 时，环丙沙星的臭氧化速率最慢，半衰期为 29 min，而 pH 值为 10 和 3 时的半衰期分别为 19 和 27 min。添加 10-1000 μM H(2)O(2)可使环丙沙星的半衰期延长至 38 min，这可能是由于 H(2)O(2)与臭氧以及自由基之间的竞争导致的。在去离子水中臭氧化环丙沙星时，曾检测到相同的产物，而本研究中在污水处理厂出水中同样检测到了这些产物，这表明产物的形成强烈依赖于 pH 值。采用琼脂扩散试验测定了剩余的抗菌活性。对于荧光假单胞菌和大肠杆菌，抗菌活性的降低与母体化合物的降解有关，而降解产物则是对抗凝结芽孢杆菌抗菌活性的主要化合物。
