Degradation of nitro-based pharmaceuticals by UV photolysis: Kinetics and simultaneous reduction on halonitromethanes formation potential

WATER RESEARCH

卷:119

Article

Dong, Huiyu¹  Qiang, Zhimin¹  Lian, Junfeng²  Qu, Jiuhui¹ 

[1] Chinese Acad Sci, Univ Chinese Acad Sci, Res Ctr Ecoenvironm Sci, Key Lab Drinking Water Sci & Technol, 18 Shuang Qing Rd, Beijing 100085, Peoples R China

[2] Jiangxi Univ Sci & Technol, Sch Architectural Surveying & Mapping Engn, 86 Hong Qi Rd, Ganzhou 341000, Peoples R China

关键词: UV photolysis;    Nitro-based pharmaceuticals;    Kinetics;    Halonitromethanes formation potential;   

DOI  :  10.1016/j.watres.2017.04.049

来源: Elsevier

【 摘 要 】

This study investigated the degradation kinetics and halonitromethanes formation potential (HNMsFP) of two nitro-based pharmaceuticals (i.e., ranitidine (RNTD) and nizatidine (NL1D)) during ultraviolet (UV) photolysis. It was found that the degradation kinetics of RNTD and NZTD exhibited pH-dependent trends, in accordance with their deprotonation equilibria. The neutral species of RNTD and NZTD were more photo-reactive than their corresponding deprotonated species, with their specific fluence-based first order rate constants varying in the range of 5.64-31.90 m(2) E-1. Both the RNTD and NZTD were prone precursors of HNM5 (with molar yields of 5.6 +/- 0.3% and 4.7 +/- 0.4%, respectively at pH 7.0). Acidic and neutral circumstances facilitated the HNM5 formation. The UV photolysis of RNTD and NZTD could reduce their HNMsFP simultaneously. Positive linear relationships between residual RNTD or NZTD concentration and HNMsFP were observed and the denitration during the UV photolysis accounted for the HNMsFP reduction. With the mandatory UV disinfection fluences in China (i.e. 20-80 mJ cm(-2)), the effective abatement of RNTD and NZTD and their HNMsFP could not be fully achieved, highlighting the necessity of increasing UV fluence or developing UV-based advanced oxidation process in future. (C) 2017 Elsevier Ltd. All rights reserved.

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