微塑料与生物炭中溶解性有机碳（B-DOC）的相互作用机制及其对B-DOC降解特征的影响研究

微塑料和生物炭来源的溶解性有机碳（B-DOC）在水环境中广泛存在，两者一旦共存，B-DOC携带的活性官能团（如羟基和羧基）会为微塑料提供多种结合位点，形成微塑料-B-DOC复合体，进而影响B-DOC的降解转化。然而，目前B-DOC自身的理化性质和降解转化尚不清楚，且针对微塑料与B-DOC间的相互作用及其对B-DOC降解特征影响的研究甚少。本项目将传统光谱、能谱与电喷雾傅立叶变换离子回旋共振质谱、流动场流分级法和电化学工作站等手段结合，从分子水平上明确不同类型生物炭中B-DOC组分的结构性质和降解特征，并在此基础上，深入考察微塑料和B-DOC间的相互作用及其对B-DOC降解特征的影响。该项目力图从分子水平上解析微塑料对B-DOC降解特性的影响以及机制，在当今微塑料在环境中广泛存在和生物炭展现出良好应用前景的大背景下，为深入认识B-DOC在水土中的环境地球化学行为提供参考依据。

Microplastic (MP) and biochar-derived dissolved organic carbon (B-DOC) widely exist in the aquatic environment. B-DOC contains various functional groups (e.g., carboxyl, hydroxyl groups) could serve as heterogeneous sites for the binding of MP, thereby forming MP-B-DOC complex. The formation of MP-B-DOC complex will affect the characteristics and degradation of B-DOC. Thus far, the molecular structure and degradation of B-DOC remain largely unclear, and limited studies were performed to study the influence of MPs on properties and degradation of B-DOC. Using combination modern spectroscopy with electrospray ionization fourier transform ion cyclotron resonance mass spectrometry (ESI-FT-ICR-MS), flow field-flow fractionation (FIFFF) and electrochemical analysis, this program investigated the properties (e.g., molecular weight distribution, molecular composition and redox property) and degradation of B-DOC fractions released from different types of biochar at molecular-scale. Then, by considering the commonly used MPs with typical structures and B-DOC fractions with significantly different compositions, it further investigated the interaction mechanism of MPs with B-DOC and explored the impact of MPs on the properties and degradation of B-DOC. This project aims to provide an insight on the effect of MPs on properties and degradation of B-DOC at molecular-scale. In the context of ubiquity of MPs and biochar in the environment, it will provide scientific basis for the deep understanding on the environmental geochemical behavior of B-DOC.