Advanced oxidation processes for the treatment of organic pollutants in wastewater suffer from difficulties in mineralization, potential risks of dissolved residues, and high oxidant consumption. In this study, radical-initiated polymerization is dominated in an UV/peroxydisulfate (PDS) process to eliminate organic pollutant of pharmaceutical metoprolol (MTP). Compared with an ideal degradation-based UV/PDS process, the present process can save four fifths of PDS consumption at the same dissolved organic carbon removal of 47.3%. Simultaneously, organic carbon can be recovered from aqueous solution by separating solid polymers at a ratio of 50% of the initial chemical oxygen demand. The chemical structure of products was analyzed to infer the transformation pathways of MTP. Unlike previous studies on simple organic pollutants that the polymerization can occur independently, the polymerization of MTP is dependent on the partial degradation of MTP, and the main monomer in polymerization is a dominant degradation product (4-(2-methoxyethyl)-phenol, denoted as DP151). The separated solid polymers are formed by repeated oxidation and coupling of DP151 or its derivatives through a series of intermediate oligomers. This proof-of-concept study demonstrates the advantage of polymerization-dominated mechanism on dealing with large organic molecules with complex structures, as well as the potential of UV/PDS process for simultaneous organic pollution reduction and organic carbon recovery from aqueous solution.

中文翻译：

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美托洛尔在 UV/PDS 过程中的转化：降解和聚合的作用和机制


高级氧化工艺处理废水中的有机污染物存在矿化困难、溶解残留物潜在风险和氧化剂消耗高等问题。在这项研究中，自由基引发聚合在紫外/过二硫酸盐（PDS）工艺中占主导地位，以消除药物美托洛尔（MTP）的有机污染物。与理想的基于降解的UV/PDS工艺相比，本工艺可以节省五分之四的PDS消耗，同时去除47.3%的溶解有机碳。同时，通过以初始化学需氧量50%的比例分离固体聚合物，可以从水溶液中回收有机碳。分析产物的化学结构以推断MTP的转化途径。与以往对简单有机污染物的研究中聚合可以独立发生不同，MTP的聚合依赖于MTP的部分降解，聚合中的主要单体是主要的降解产物（4-(2-甲氧基乙基)-苯酚，记为如 DP151）。分离出的固体聚合物是通过一系列中间低聚物对DP151或其衍生物进行重复氧化和偶联而形成的。这项概念验证研究证明了以聚合为主导的机制在处理具有复杂结构的大有机分子方面的优势，以及 UV/PDS 工艺同时减少有机污染和从水溶液中回收有机碳的潜力。