蓝藻水华对湖泊水体矿质胶体颗粒分散/团聚及界面吸附特性的影响及机理

Lake is the important source of drinking water, while the high contents of mineral colloidal particles (MCPs) significantly inhibit its function and water safety. Thus, the environmental effect of MCPs has attracted increasing attention. Our previous investigations showed that the dissolved organic matters (DOM) released by the bloom-forming cyanobacteria could alter the environmental effects of MCPs, while the mechanism is not clear till now. Knowledge on the influence and mechanism of DOM released by the bloom-forming cyanobacteria on the dispersion/agglomeration and interfacial adsorption of MCPs is helpful for exploring the environmental effects of MCPs as well as designing the water security technology. This project aims to 1) investigate the effects of different organic compositions on the dispersion/agglomeration of MCPs, and find out the key organic compositions which significantly influence the dispersion/agglomeration process of MCPs during the formation process of cyanobacterial blooms; 2) establish the three-dimensional structural model of dispersion/agglomeration process and the relationship between the process and interfacial properties of MCPs by combining the molecular dynamic simulation and two-dimensional correlation spectroscopy; 3) explore the adsorption and distribution mode of pollutants between the different organic compositions and MCPs through the application of high resolution spectroscopy and mathematical model; 4) reveal the influence mechanism of cyanobacterial blooms on the environmental effects of MCPs. This project contributes to our understanding of the elucidation of the high turbidity reason and pollutant cycling, and can also provide helpful technical guidance for the ecological restoration of water quality.

湖泊是饮用水的重要来源，但水中高含量矿质胶体颗粒严重影响到湖泊功能发挥和水质安全，其环境效应已引起研究者广泛关注。申请者在前期研究中发现，蓝藻细胞释放的有机质可影响胶体颗粒环境效应，但具体机制尚不明确。通过研究水华期间溶解有机质对矿质胶体颗粒分散/团聚及界面吸附特性的影响及机理，将有助于颗粒环境效应的解析及水质安全净化技术的研发。项目以典型富营养浅水湖泊太湖为研究对象，探讨不同有机组分对矿质胶体颗粒分散/团聚的行为过程，筛选水华不同阶段影响颗粒分散/团聚的关键组分物质；结合分子动力学模拟和二维相关光谱技术，构建颗粒分散/团聚的三维结构模型及其与界面性质变化的关联性；再应用高分辨光谱和数学模型，探明污染物在不同有机组分和颗粒团聚体间的吸附分配模式，以期揭示蓝藻水华对矿质胶体颗粒环境效应的影响机理。该项目在湖泊水体高浊度成因及污染物循环解析方面具有重要理论价值，也可为水质生态修复提供技术指导。

湖泊是饮用水的重要来源，但水中高含量胶体颗粒严重影响到湖泊功能发挥和水质安全，其环境效应已引起研究者广泛关注。项目以典型富营养浅水湖泊太湖为研究对象，开展了湖泊胶体颗粒的含量来源、结构表征和稳定/团聚特性，发现湖泊胶体颗粒的含量约2-20mg/L,沉积物再悬浮是湖泊胶体颗粒的重要来源，约贡献上覆水体50-55%的胶体颗粒含量；分析了湖泊水华生消过程中蓝藻胞外聚合物（EPS）的含量及分子量分布特征，发现EPS与胶体颗粒具有良好的表面吸附效率，但高分子量EPS与颗粒的吸附效能（4.81mg/g）显著高于总EPS（3.77mg/g）和低分子量EPS（2.44mg/g）；蓝藻EPS吸附后可通过空间位阻和静电斥力作用显著提高胶体颗粒的稳定性和湖泊水体浊度，EPS中的高分子量组分是影响颗粒稳定性的关键分子量区间，且芳香性基团是影响颗粒稳定的关键基团；胶体颗粒表面可有效负载重金属污染物（40-60mg/g），从而影响污染的迁移转化和生物有效性，蓝藻EPS可通过竞争颗粒表面吸附位点而减小胶体颗粒对重金属的吸附效能，从而提高重金属污染物的迁移性。该项目研究结果揭示了富营养浅水湖泊水体高浊度成因及污染物的迁移循环过程，还可为污染水体生态修复提供技术指导。