纳米二氧化锰与水环境界面相互作用规律及机制的研究

Due to its excellent adsorption ability, more and more researches about the safety and security of drinking water have been focused on heavy metal removal technologies based on nanosized manganese oxides. The interactions between nanosized manganese oxides and surfaces in aquatic environments can significantly impact the removal of heavy metals from waters. In this study, nanosized MnO2 (nMnO2) is selected as a model manganese oxides. Based on the researches of interactions between nMnO2 particles, deposition of these particles on representative interfaces (i.e., SiO2, Fe2O3, and Al2O3 surfaces) in aquatic surfaces are conducted by using QCM-D technique. Moreover, characterization techniques including TEM, XRD, XPS, and FTIR are used to verify the unknown mechanisms of the interactions between nMnO2 particles and the interfaces in aquatic environments. Specific topics include: deposition kinetics of nMnO2 particles on typical interfaces was investigated to explore the regularity of interactions between nMnO2 particles. Theoretical models and the deposition layer characteristics are used to interpret the interactions obtained from the deposition kinetics. The effects of common organic matter in waters on the deposition kinetics of nMnO2 particles on the selected representative surface and analysis of deposition layer characteristics are conducted. Mechanisms why these organic matter impact the interactions and thus the deposition kinetics are also to be explored. The results are expected to provide basic theoretical support for the application and improvement of heavy metal removal technology based on manganese oxide, which is of great significance to the safety of drinking water.

由于纳米锰氧化物具有良好的吸附能力，基于纳米锰氧化物的重金属去除技术已成为研究热点，而其与水环境界面相互作用是影响重金属去除的重要因素。本研究以纳米MnO2（nMnO2）为代表性纳米锰氧化物，利用石英晶体微天平（QCM-D）技术，构建nMnO2在代表性水环境界面（即SiO2、Fe2O3和Al2O3界面）上沉积的实验体系，借助TEM、XRD、XPS、FTIR等表征技术，研究nMnO2与水环境界面的相互作用规律及机制。具体内容包括：nMnO2在代表性界面上的沉积动力学，探求nMnO2的界面作用规律，并建立理论模型，结合沉积层的特征，揭示nMnO2的界面作用机制；并深入研究有机物对沉积动力学的影响规律，阐明有机物对nMnO2与代表性界面作用的影响机制。预期成果将为基于锰氧化物的重金属去除技术的应用和改进提供基础理论支撑，对保障饮用水安全具有重要意义。

由于纳米锰氧化物具有良好的吸附能力，基于纳米锰氧化物的重金属去除技术已成为研究热点，而其与水环境界面相互作用是影响重金属去除的重要因素。本研究探索了离子强度和天然有机质对纳米MnO2在代表性水环境界面二氧化硅（SiO2）、氧化铁（Fe3O4）和氧化铝（Al2O3）上沉积动力学的影响机制，得到了纳米MnO2在不同界面上沉积的关键参数。并通过理论模型对纳米MnO2与界面之间的相互作用能进行计算，从理论上验证了纳米MnO2在水环境界面上沉积的主导作用力。界面类型，离子强度以及有机物性质均会对沉积层的性质有一定影响。在此基础上，还探究了离子强度、界面类型、pH值和天然有机质等常见环境因子对纳米MnO2在上述三种代表性水环境界面上释放行为的影响，深入探讨了nMnO2与代表性界面作用规律以及相关环境因素的影响机制。同时，由于离子水化能力不同产生的离子特性对纳米MnO2与界面的相互作用规律也有着重要的影响。本研究为从理论角度定量评估纳米MnO2在水环境中的迁移潜力以及从微观作用的角度理解基于纳米科技产生的生态环境和人类健康风险评估有重要意义，对为进一步从理论上研究水处理工艺中痕量重金属去除提供了理论支撑。