微塑料是环境中一类不断增加的新兴污染物。作为传统塑料的替代品，可生物降解塑料的应用越来越多。进入环境中的微塑料能不断老化并吸附多种有机污染物，增加微塑料的毒性效应。抗生素是环境中广泛检出的一类有机污染物，微塑料与抗生素复合污染现象非常普遍。但当前针对微塑料与抗生素相互作用的研究还仅局限于不可降解微塑料。与传统不可降解微塑料相比，可生物降解微塑料进入环境后，粒径及表面性质可在短时间内产生变化，显著提高其迁移和对污染物的吸附能力，产生更高的环境风险。基于此，本项目拟选取几种应用广泛的可生物降解微塑料，系统研究这些微塑料在不同环境条件下的老化行为，以及对典型四环素类抗生素的吸附解析和光化学转化规律，通过建立原位红外和拉曼光谱研究这些微塑料的老化过程及其与与抗生素作用的位点和转化方式，结合活性自由基表征和理论计算揭示界面过程的分子机制。研究结果将为合理评估可生物降解微塑料的环境风险提供科学依据。

Microplastics are increasing emerging contaminants in the environment. As the substitute to traditional non-degradable plastics, biodegradable plastics are increasingly used. After entering environment, microplastics would undergo continuously aging and adsorb a variety of organic pollutants, increasing the toxicity of microplastics. Antibiotics are a type of organic pollutants widely detected in the environment and the microplastics and antibiotics combined pollution is a common phenomenon. However, current researches on the interactions between microplastics and antibiotics mainly focuses on non-degradable materials. Compared with traditional non-degradable microplastics, degradable microplastics would undergo changes of sizes and surface properties in relatively short periods after entering the environment, which would significantly improve the migration ability and adsorption capacity toward pollutants of microplastics, resulting in higher environmental risks. In this study, several kinds of biodegradable microplastics will be selected. Comprehensive investigation will be conducted for the aging behavior of these microplastics under different environmental conditions, as well as the adsorption, desorption and photochemical conversion of typical antibiotics, i.e. tetracyclines, by these microplastics. In-situ Infrared and Raman spectroscopy will be established to study the aging process of biodegradable microplastics under different environmental conditions and the interaction sites and conversion modes between the microplastics and the antibiotics. In the combination analysis of active free radical characterization and theoretical calculation, the molecular mechanism of the interface process will be revealed. The research results could provide scientific basis for the reasonable evaluation of the environmental risks of biodegradable microplastics.