有机污染土壤降解菌/粘土矿物界面反应及其环境效应研究

Adopting mineral interface physicochemical theory and method, modern spectroscopy and surface analysis test technology and solid-liquid inter facial chemistry experiments, the characteristics of interfacial reaction between degrading bacteria and clay minerals in organic contaminated soil in South China and the variation features of their microstructures were studied, as well as the surface complexation, the irreversible adsorption/desorption and the crosslinking mechanism of degrading bacteria and its extracellular polymeric substances and clay minerals. On this basis, the synergistic microbial degradation of pesticide and petroleum pollutants by the complex consisting of clay minerals-immobilized degrading bacteria and clay minerals, the factors influencing synergistic microbial degradation and the environmental significance of biodegradation were systematically researched. The charge distribution model on surface of variable charge of complex, the bonding character of degrading bacteria with clay minerals, the immobilization, the synergistic microbial degradation and the relationship between it and variation of microstructures were mainly investigated. This could illuminate the immobilization of degrading bacteria by clay minerals in contaminated soil, the interface reaction mechanism and kinetic features of reaction, which would further reveal the effect of surface activity of clay minerals-immobilized degrading bacteria in contaminated soil in South China on environmental geochemical behavior about organic pollutants. This not only provided essential experimental data for studying the kinetics mechanism of interfacial reaction between degrading bacteria and clay minerals in contaminated soil, the immobilization and the synergistic degradation, but also had important guiding significance for the rational exploitation of China's rich clay mineral resources, the development of novel and highly efficient environmental and genetic-engineering materials.

采用矿物界面物理化学的理论和方法、现代谱学和表面分析测试技术、固-液界面化学实验，研究华南地区有机污染土壤中降解菌/粘土矿物界面反应特性及其微结构变化特征；降解菌及其胞外聚合物与粘土矿物表面络合、非可逆吸附/解吸及交联机理。在此基础上研究粘土矿物固定化降解菌复合体对农药、石油污染物协同微生物降解、影响因素及其环境意义。重点研究降解菌/粘土矿物复合体可变电荷表面的电荷分布模式、降解菌与粘土矿物表面成键特征、固定化作用、协同降解性及其与微结构变化间的关系，以阐明粘土矿物对污染土壤中降解菌的固定、界面反应机理及反应动力学特征。进一步揭示华南地区污染土壤中粘土矿物固定降解菌表面活性对有机污染物环境地球化学行为的调控规律。为污染土壤中降解菌/粘土矿物界面作用的动力学机制和固定化、协同降解研究提供重要的实验数据。同时对合理开发我国丰富的粘土矿物资源、研制新型高效环境和基因工程材料也有重要指导意义。

本项目通过研究华南地区污染土壤中降解菌（GY2B菌和铜绿假单胞菌）/粘土矿物界面反应特性及其微结构变化特征；降解菌及其胞外聚合物与粘土矿物表面络合、非可逆吸附/解吸及交联机理。取得以下主要成果：.1、系统研究了GY2B降解菌对有机污染物苯酚的降解特性，发现GY2B菌对苯酚具有较强的降解能力，但易受恶劣环境影响而抑制其降解性能；.2、粘土矿物/GY2B复合体能显著提升对有机污染物的降解性能，高岭土吸附固定对GY2B具有保护作用，能拓宽菌体降解浓度宽度，并大大缩短降解周期；复合体能保护降解菌免受过酸、过碱、重金属等恶劣环境毒害；.3、采用包埋法固定GY2B制成固定化小球，确定了聚乙烯醇、高岭土、海藻酸钠、GY2B菌悬液四者的最佳投加比例。固定化小球能为GY2B提供稳定的降解条件和极强的环境适应能力，同时具有优秀的循环再用特性和长久保存的性能；.4、研究了培养及非培养状态下铜绿假单胞菌（P. aeruginosa）对Cr(VI)的还原性能，分析了生长态P. aeruginosa还原Cr(VI)的环境影响因子及静息态P. aeruginosa对Cr(VI)的还原机理；.5、在粘土矿物/P. aeruginosa界面反应过程中粘土矿物与P. aeruginosa 二者间存在协同作用，粘土矿物可显著促进P. aeruginosa对Cr(VI) 还原作用。.本项目研究成果可为污染土壤中降解菌/粘土矿物界面作用的动力学机制和固定化、协同降解研究提供重要的实验数据。同时，为合理开发我国丰富的粘土矿物资源、研制新型高效的环境材料和污染土壤的原位修复提供科学依据。