湖泊沉积物中粘土矿物的层间溶解性有机质特性、微结构变化及插层机制

Domestic and foreign scholars have done extensive researches regarding surfactant-synthetic and DOM naturally-formed organoclay. However little research is done on DOM occurrence among clay mineral interlayer. The study of interlayer DOM characteristics, microstructure variation and related intercalation mechanisms in organoclay remains to be insufficient. This project intends to collect sediments of lake as the research object. By a combination of methods including spectroscopy, electron microscopy and pore structure analysis, the project attempts to verify main components, the relative content and molecular structure of DOM in interlayer of clay mineral, to prove effect of interlayer DOM characteristics on clay microstructure and to demonstrate the main mechanism of DOM occurrence in the organoclay interlayer. Research results will be contribute to a better understanding of environmental geochemical cycles and effects of DOM in lake ecosystems, and provide a solid theoretical basis for clay mineral transformation and fate of pollutants in environments.

对通过表面活性剂合成及溶解性有机质（DOM）天然形成的有机粘土，目前国内外学者进行了大量研究。但DOM在有机粘土层间赋存的研究工作十分薄弱，有机粘土的层间DOM赋存特征、微结构变化和相关插层机制仍不清楚。本项目拟选择湖泊沉积物中粘土矿物为研究对象，结合光谱学、电子显微学及孔结构分析等方法，查明粘土矿物层间DOM的主要组成、相对含量及分子结构，探明DOM在粘土矿物层间赋存对其微结构的影响，阐明有机粘土层间DOM赋存的主要机制。研究成果将有助于加深湖泊生态系统中DOM环境地球化学循环与效应的认识，为沉积物中粘土矿物成岩转化和污染物在环境中的归趋提供扎实的理论依据。

溶解性有机质和黏土矿物结合形成的有机黏土是有机质赋存于沉积物的重要方式。有机黏土的形成及其有机质在湖泊、河流和海洋中的迁移和转化对于揭示全球有机质环境地球化学循环及污染物在环境中的归趋具有重要的意义。本项目揭示了湖泊沉积物中的典型黏土矿物伊利石、高岭石生成有机黏土可有效固定有机质，黏土矿物种类和有机质组分均对有机质在黏土矿物表面的固定产生重要的作用。赋存于有机黏土层间域的溶解性有机质在钠离子影响下更易脱附，而吸附于有机黏土外表面的有机质更易在黏土表面赋存，溶解性有机质在黏土矿物的赋存位点影响有机质在黏土矿物的稳定性。这些结果对沉积物中有机质循环和污染物在环境中的归趋提供扎实的理论依据。