Influence Rule of Organic Solvents Methanol from Sample Preparation on Degradation Rate and Mechanism of Atrazine in UV-based Oxidation Processes

作者：Yucan Liu, Miaomiao Su, Yan Zhang, Jinming Duan, Wei Li · 发表于：化学学报 · 年份：2019 · DOI：10.6023/a18090365 · 被引用次数：4 · 研究领域：Water Quality Monitoring and Analysis

Stock solutions of organic micro-pollutants with low water solubility are commonly prepared using organic solvents in laboratory studies on degradation of these organic compounds.Dilution of the stock solution unavoidably introduces a small amount of organic solvent into the experimental working solutions.This could possibly affect the estimation of the degradation rate constants (k obs ) of these organic micro-pollutants by UV-based oxidation processes.To demonstrate this problem, the effect of organic solvents on the degradation rate of atrazine (ATZ) has been investigated in the sole-UV, UV/H 2 O 2 and UV/TiO 2 process at the concentration levels that would likely be derived from stock solutions.Organic solvent methanol (MeOH) commonly used for stock-solution preparation was selected.The degradation of ATZ was investigated under ultraviolet irradiation (253.7 nm).The reaction was conducted in an annular photochemical reactor, in the axis of which a low-pressure mercury lamp (LPUV) was installed.The photon flux into the solution from the LPUV was determined to be at 1.18×10 -7 Einstein/s.A magnetic stirrer was located at the bottom of the reactor to maintain homogeneity of the reacting solution.A thermostatic water recirculation system was used to control the solution temperature at 20±0.5 ℃.Prior to irradiation, the mercury lamp was ignited for 30 min for a stable output.UV photo-oxidation was performed with ultrapure water containing an initial 0.1 or 5 mg/L ATZ and diffe...