【作者】 蔡婷婷； 杨琛；

【Author】 Cai Tingting;Yang Chen;South China University of Technology, School of Environment and Energy;Key Laboratory of Industrial Pollution Control and Ecological Restoration;

【机构】 华南理工大学环境与能源学院； 工业污染控制与生态恢复重点实验室；

【摘要】 塑料的广泛使用导致MPs在环境中无处不在,TWP作为MPs的一大来源,有必要研究TWP表面EPFRs和ROS的形成机制,以进一步评估其环境风险。在室温、高湿度条件下(25℃,85%RH)进行TWP的光老化实验。研究发现,UVC可以诱导TWP上EPFRs的形成。TWP上的EPFRs丰度随老化进程逐渐增加,以碳原子中心自由基为主。结合表征分析发现,EPFRs的产生主要是因为橡胶中共价键的断裂。在紫外光照下,聚合物分子中的α-亚甲基发生氧化脱氢形成R·,而后引发自由基的链反应,TWP上的EPFRs主要是R·、ROO·、RO·和羟基过氧化物。另外,TWP上EPFRs诱导了ROS的产生,EPFRs通过电子转移或直接分解形成ROS,生成的ROS介导TWP的光老化过程,促进了聚合物的光氧化。TWP上EPFRs和ROS的积累增加了对生物体的健康威胁,但也加速了聚合物的光降解进程。为了全面评估TWP的环境风险,需要进一步研究降解中间体及降解产物的毒性和影响。更多还原

【Abstract】 The widespread use of plastics has led to the ubiquity of MPs in the environment, and as a major source of MPs, it is necessary to study the formation mechanism of environmental persistence free radicals(EPFRs) and reactive oxygen species(ROS) on the surface of TWP to further assess their environmental risks. The photoaging experiment of TWP was performed at room temperature and high humidity(25°C, 85%RH). The results suggested that UVC can induce the formation of EPFRs on TWP. The abundance of EPFRs on TWP gradually increased with the aging process, and it suggests that EPFRs are designated as carbon-centered radical species with g-factors less than 2.0030. Combined with characterization analysis, it is found that the production of EPFRs was mainly due to the breaking of covalent bonds of rubber. Under ultraviolet light, theα-methylene in the polymer molecules is oxidized and dehydrogenated to form R·, and then trigger a chain reaction of free radicals, and the EPFRs on TWP are mainly R·, ROO·, RO· and hydroxyperoxides. In addition, EPFRs on TWP induce the production of ROS, EPFRs form ROS through electron transfer or direct decomposition, and the generated ROS mediates the photoaging process of TWP and promotes the photooxidation of polymers. The accumulation of EPFRs and ROS on TWP increases the health threat to organisms, but also accelerates the photodegradation process of polymers. In order to fully assess the environmental risks of TWP, further research is needed on the toxicity and effects of degradation intermediates and degradation products.更多还原