Advanced Interdisciplinary Institute of Environment and Ecology, Beijing Normal University at Zhuhai, Zhuhai 519087, China; State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, China.
Advanced Interdisciplinary Institute of Environment and Ecology, Beijing Normal University at Zhuhai, Zhuhai 519087, China; State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, China.
J Environ Sci (China). 2023 Jun;128:107-116. doi: 10.1016/j.jes.2022.07.008. Epub 2022 Jul 16.
The degradation of metoprolol (MTP) by the UV/sulfite with oxygen as an advanced reduction process (ARP) and that without oxygen as an advanced oxidation process (AOP) was comparatively studied herein. The degradation of MTP by both processes followed the first-order rate law with comparable reaction rate constants of 1.50×10sec and 1.20×10sec, respectively. Scavenging experiments demonstrated that both e and H• played a crucial role in MTP degradation by the UV/sulfite as an ARP, while SO was the dominant oxidant in the UV/sulfite AOP. The degradation kinetics of MTP by the UV/sulfite as an ARP and AOP shared a similar pH dependence with a minimum rate obtained around pH 8. The results could be well explained by the pH impacts on the MTP speciation and sulfite species. Totally six transformation products (TPs) were identified from MTP degradation by the UV/sulfite ARP, and two additional ones were detected in the UV/sulfite AOP. The benzene ring and ether groups of MTP were proposed as the major reactive sites for both processes based on molecular orbital calculations by density functional theory (DFT). The similar degradation products of MTP by the UV/sulfite process as an ARP and AOP indicated that e/H• and SO might share similar reaction mechanisms, primarily including hydroxylation, dealkylation, and H abstraction. The toxicity of MTP solution treated by the UV/sulfite AOP was calculated to be higher than that in the ARP by the Ecological Structure Activity Relationships (ECOSAR) software, due to the accumulation of TPs with higher toxicity.
本文比较研究了 UV/亚硫酸盐在有氧条件下作为高级还原过程（ARP）和无氧条件下作为高级氧化过程（AOP）降解美托洛尔（MTP）的过程。这两种过程中 MTP 的降解均遵循一级反应动力学规律，相应的反应速率常数分别为 1.50×10sec 和 1.20×10sec。猝灭实验表明，在 UV/亚硫酸盐作为 ARP 中，e 和 H•均对 MTP 的降解起关键作用，而在 UV/亚硫酸盐 AOP 中，SO 是主要氧化剂。UV/亚硫酸盐作为 ARP 和 AOP 降解 MTP 的动力学具有相似的 pH 依赖性，在 pH 约为 8 时获得最小速率。结果可以通过 pH 对 MTP 形态和亚硫酸盐形态的影响得到很好的解释。从 UV/亚硫酸盐 ARP 降解 MTP 中鉴定出了 6 种转化产物（TPs），在 UV/亚硫酸盐 AOP 中还检测到了另外 2 种 TPs。基于密度泛函理论（DFT）的分子轨道计算，提出 MTP 的苯环和醚基是这两种过程的主要反应活性位点。UV/亚硫酸盐过程中 MTP 的相似降解产物作为 ARP 和 AOP 表明，e/H•和 SO 可能具有相似的反应机制，主要包括羟化、脱烷基和 H 提取。根据生态结构活性关系（ECOSAR）软件计算，UV/亚硫酸盐 AOP 处理的 MTP 溶液的毒性高于 ARP，这是由于毒性更高的 TPs 的积累所致。
