In this study, a new photo-irradiated reductive dechlorination pathway and the underlying transformation mechanism are described for poly(vinyl chloride) microplastics (PVC-MPs). PVC-MPs underwent photo-reductive dechlorination process with the release of chloride ions. This reaction could be facilitated in the presence of indole-3-acetic acid (IAA) and hexadecyltrimethylammonium bromide (CTAB) under neutral pH and simulated sunlight irradiation conditions. Electrostatic interaction between IAA and CTAB produced neutral IAA/CTAB complex, which might account for the enhanced adsorption of IAA on PVC powders. Upon photo-irradiation, the adsorbed IAA was excited to generate hydrated electrons (e_aq⁻), which could pass through a shorter distance to PVC-MP surface than that derived from homogeneous IAA molecules in aqueous solution. Transient spectra of laser flash photolysis provided direct evidence for the generation of e_aq⁻, which supported the proposed dechlorination mechanism. Based on the results of attenuated total reflectance/Fourier transform infrared (ATR/FTIR) and Raman spectra, C-Cl bond cleavage and polyene formation were involved in the structural transformation of PVC-MPs. Due to the hydrophobic effects and π-π interactions between aromatic rings and polyene structures in PVC-MP surface, the PVC-MP powders irradiated in the presence of IAA/CTAB showed an enhanced sorption for both hydrophobic and hydrophilic aromatic chemicals.

在这项研究中，描述了一种新的光辐照还原性脱氯途径及其潜在的转化机理，用于聚氯乙烯微塑料（PVC-MPs）。PVC-MP经过光还原脱氯过程，释放出氯离子。在中性pH和模拟阳光照射条件下，在吲哚-3-乙酸（IAA）和十六烷基三甲基溴化铵（CTAB）的存在下可以促进该反应。IAA和CTAB之间的静电相互作用产生了中性的IAA / CTAB复合物，这可能解释了IAA在PVC粉体上的吸附增强。在光照射时，该吸附IAA被激发，以产生水合的电子（e_水溶液^-），它通过PVC-MP表面的距离比水溶液中均质IAA分子的距离短。激光闪光光解瞬态谱电子的产生提供了直接的证据_含水^- ，它支持拟议的脱氯机制。基于全反射衰减/傅立叶变换红外光谱（ATR / FTIR）和拉曼光谱的结果，C-Cl键断裂和多烯形成参与了PVC-MP的结构转变。由于PVC-MP表面芳香环与多烯结构之间的疏水作用和π-π相互作用，在IAA / CTAB存在下辐照的PVC-MP粉末对疏水和亲水芳香族化学物质的吸附均增强。