Department of Civil and Environmental Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong.
Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, School of Environmental Science and Engineering, Sun Yat-Sen University, Guangzhou 510275, China.
Chemosphere. 2016 May;150:731-739. doi: 10.1016/j.chemosphere.2015.12.046. Epub 2015 Dec 28.
N-Nitrosopyrrolidine (NPYR) is an emerging contaminant in drinking water and wastewater. The degradation kinetics and mechanisms of NPYR degradation by the O3/UV process were investigated and compared with those of UV direct photolysis and ozonation. A synergistic effect of ozone and UV was observed in the degradation of NPYR due to the accelerated production of OH• by ozone photolysis. This effect was more pronounced at higher ozone dosages. The second-order rate constants of NPYR reacting with OH• and ozone was determined to be 1.38 (± 0.05) × 10(9) M(-1) s(-1) and 0.31 (± 0.02) M(-1) s(-1), respectively. The quantum yield by direct UV photolysis was 0.3 (± 0.01). An empirical model using Rct (the ratio of the exposure of OH• to that of ozone) was established for NPYR degradation in treated drinking water and showed that the contributions of direct UV photolysis and OH• oxidation on NPYR degradation were both significant. As the reaction proceeded, the contribution by OH• became less important due to the exhausting of ozone. Nitrate was the major product in the O3/UV process by two possible pathways. One is through the cleavage of nitroso group to form NO• followed by hydrolysis, and the other is the oxidation of the intermediates of amines by ozonation.
N-亚硝基吡咯烷 (NPYR) 是饮用水和废水中新兴的污染物。研究了 O3/UV 工艺降解 NPYR 的动力学和机制，并与 UV 直接光解和臭氧氧化进行了比较。由于臭氧光解加速了 OH•的产生，在 NPYR 的降解过程中观察到臭氧和 UV 的协同作用。在较高的臭氧剂量下，这种效果更为明显。确定 NPYR 与 OH•和臭氧反应的二级速率常数分别为 1.38(±0.05)×10(9) M(-1) s(-1)和 0.31(±0.02)M(-1) s(-1)。直接 UV 光解的量子产率为 0.3(±0.01)。建立了一个使用 Rct（OH•暴露与臭氧暴露的比值）的经验模型，用于处理后的饮用水中 NPYR 的降解，表明直接 UV 光解和 OH•氧化对 NPYR 降解的贡献都很重要。随着反应的进行，由于臭氧的耗尽，OH•的贡献变得不那么重要。硝酸盐是 O3/UV 工艺中的主要产物，有两种可能的途径。一种是通过亚硝基基团的裂解形成 NO•，然后水解，另一种是臭氧氧化胺的中间体。
