随着塑料制品的大量使用和丢弃，在环境因子作用下持续释放的塑料微粒对生态系统及人类健康产生较大风险。因此，阐明微塑料在环境中发生的变化及与环境介质的交互作用是评估其环境行为和环境效应亟待解决的问题。本项目以环境中最常检出的四种微塑料为目标物，以铁氧化物为环境中活性物质代表，结合表面形貌与微观结构表征、序批实验、荧光标记、自由基分析、色谱分析及二维红外光谱（2D-FTIR-COS）分析等多种现代化分析表征手段，明确光照、高温及氧化剂等环境要素作用下微塑料的老化过程、特征和机理，揭示不同老化程度微塑料与铁氧化物的微观界面作用特性和机制，分析老化对微塑料与铁氧化物之间微观界面的影响，探明铁氧化物与微塑料的微观界面作用对微塑料老化的影响机制。通过以上研究，期望在环境中活性物质介导下微塑料的界面行为与老化机制方面有新的认识，并为科学合理的认识微塑料的环境行为及生态风险评估提供理论依据。

With the extensive use and discard of plastic products, the continuous release of microplastic particles under the action of environmental factors led to great risks to the ecosystem and human health. It is urgent to clarify the changes of microplastics in the environment and their interaction with environmental media in order to evaluate their environmental behaviors and effects. In this proposal, we will use four kinds of microplastics which are frequently detected in the environment. Meanwhile, iron oxides will be used as the actives of the environmental geochemistry. Combined with surface morphology and microstructure characterization, batch experiments, fluorescence labeling, free radical analysis, chromatographic analysis and 2D-FTIR-COS analysis to clarify the aging process, characteristics and mechanism of microplastics under the exposure of light, high temperature and oxidant. The microinterface characteristics and mechanism of aged microplastics and iron oxides will be revealed to understand the effects of aging on microinterface between microplastics and iron oxides.Then the effect of iron oxide on the aging process of microplastics will be further investigated. Overall, it is expected to have a new understanding of the interface behavior and aging mechanism of microplastics mediated by active substances in the environment, thus providing a theoretical basis for the environmental behavior and ecological risk assessment of microplastics.