Abstract：
The ubiquitous occurrence of microplastics in water and wastewater is a growing concern. In this study, the chemical transformation and organic release of virgin and UV-aged thermoplastic polyurethane (TPU) polymers during chlorination were investigated. As compared to virgin TPU polymer, the UV-aged TPU polymer exhibited high chlorine reactivity with noticeable destruction on its surface functional groups after chlorination, which could be ascribed to the UV-induced activation of hard segment of TPU backbone and increased contact area. The concentrations of leached organics increased by 1.6-fold with obviously high abundances of low-molecular-weight components. Additives, monomers, compounds relating to TPU chain extension, and their chlorination byproducts contributed to the increased organic release. Meanwhile, the formation of chloroform, haloacetic acids, trichloroacetaldehyde, and dichloroacetonitrile increased by 3.8-, 1.7-, 4.9-, and 2.4-fold, respectively. Two additives and six chlorination byproducts in leachate from chlorinated UV-aged TPU were predicted as highly toxic, e.g., butyl octyl phthalate, palmitic acid, 2,6-di-tert-butyl-1,4-benzoquinone, and chlorinated aniline. Evaluated by human hepatocarcinoma cells, the 50% lethal concentration factor of organics released from chlorinated UV-aged TPU was approximately 10% of that from its virgin counterpart, indicating a substantially increased level of cytotoxicity. This study highlights that the release of additives and chlorination byproducts from the chemical transformation of UV-aged microplastics during chlorination may be of potentially toxic concern.
摘要：
微塑料在水和废水中的普遍存在越来越受到关注。在这项研究中,研究了氯化过程中原始和紫外线老化的热塑性聚氨酯（TPU）聚合物的化学转化和有机释放。与纯TPU聚合物相比，紫外线老化的TPU聚合物表现出高的氯反应性，在氯化后其表面官能团明显破坏，这可能归因于紫外线诱导的TPU骨架硬段的活化和接触面积的增加。浸出有机物的浓度增加了1.6倍，低分子量成分的丰度明显很高。添加剂,单体，与TPU扩链有关的化合物，它们的氯化副产物有助于增加有机释放。同时,氯仿的形成，卤代乙酸,三氯乙醛,二氯乙腈增加3.8-，1.7-，4.9-，和2.4倍，分别。氯化紫外线老化TPU的渗滤液中的两种添加剂和六种氯化副产物被预测为剧毒，例如，邻苯二甲酸丁酯辛酯,棕榈酸,2,6-二叔丁基-1,4-苯醌，和氯化苯胺。通过人类肝癌细胞评估，从氯化紫外线老化的TPU释放的有机物的50％致死浓度因子约为其原始对应物的10％，表明细胞毒性水平显著增加。这项研究强调，在氯化过程中，紫外线老化的微塑料的化学转化释放出的添加剂和氯化副产物可能具有潜在的毒性问题。
