锰离子强化高铁酸钾去除重金属离子的机理研究

Heavy metal pollution in water has the characteristics of high toxicity, easy enrichment, slow metabolism and difficult removal. The control of heavy metal pollution in source water is a critical issue for the assurance of drinking water quality in China. The reduction product of potassium ferrate (nano-scale iron oxide) is characteristic of small particle size, thin hydrated layer, good dispersibility, large specific surface area, and abundant hydroxyl functional group on the surface, and hence could easily adsorb and complex heavy metal ions in water, and can effectively control the heavy metal pollution in water. However, the practical application of ferrate is limited by the high cost of ferrate preparation as well as the great dosage of ferrate in relevant water treatment. Applicants found previously that the presence of small amounts of Mn(II) ions can significantly improve the removal efficiency of heavy metals by potassium ferrate, but the underlying mechanism is still unclear. With the aim of enhancing the removal of heavy metals in water by potassium ferrate, this study intends i) to investigate the reaction kinetics between Mn(II) and Fe(VI), the interface characteristic of the reaction products as well as the aggregation and flocculation of the iron-manganese mixtures; ii) to study the variation of element valence state and the chemical form transformation during the removal of heavy metals by Fe(VI)-Mn(II) process, to analyze the oxidation/reduction, adsorption/complexation and other reaction processes in the system, and thus to clarify the interaction mechanism between the iron-manganese mixtures and heavy metal ions; iii) to investigate the influence of water background on the removal of heavy metals in water by Fe(VI)-Mn(II) process, to optimize the scheme parameters and thus to provide theoretical support and technical reserves for the control of heavy metal pollution in source water.

重金属污染具有毒性强、易富集、代谢慢、去除难等特点。源水重金属污染控制是我国饮用水水质保障的重要课题。高铁酸钾的还原产物（纳米级铁氧化物）粒径小、水化层薄、分散性好、比表面积大、表面富含羟基官能团，易吸附、络合水中的重金属离子，可有效控制水体重金属污染。但高铁酸钾制备成本高、水处理投量大，限制其实际应用。申请人前期发现，微量锰离子的存在可显著提高高铁酸钾对重金属的去除效率，但作用机理尚不明晰。本项目以强化高铁酸钾去除水中重金属为目标，研究二价锰与高铁酸钾的反应动力学及产物的理化性质，探讨铁-锰混合物的凝聚、絮凝规律；研究二价锰/高铁酸钾去除重金属过程中元素价态及化学形态转化，分析体系中氧化/还原、吸附/络合等反应过程，阐明铁-锰混合物与重金属离子的作用机制；探讨水质背景因素对二价锰/高铁酸钾除重金属效果的影响，提出最优化的重金属污染控制方案，为源水重金属污染控制提供理论支持及技术储备。

重金属污染具有毒性强、易富集、代谢慢、去除难等特点。源水重金属污染控制是我国饮用水水质保障的重要课题。高铁酸钾的还原产物（纳米级铁氧化物）粒径小、水化层薄、分散性好、比表面积大、表面富含羟基官能团，易吸附、络合水中的重金属离子，可有效控制水体重金属污染。但高铁酸钾制备成本高、水处理投量大，限制其实际应用。本项目围绕二价锰离子复合高铁酸盐[Fe(VI)]去除水中重金属开展了三方面研究：（1）研究了二价锰离子与高铁酸钾复合作用对重金属铊、砷及硒的去除效果与规律；（2）解析了二价锰离子与高铁酸钾复合作用时铁-锰元素赋存结构的转化规律及相互作用机制；（3）阐明了二价锰离子与高铁酸钾复合作用时铁-锰混合物的凝聚、絮凝规律，考察了水质背景因素对二价锰/高铁酸钾除重金属效果的影响，提出了最优化的重金属污染控制方案，为源水重金属污染控制提供理论支持及技术储备。围绕上述研究，在SCI期刊发表研究论文13篇(以第一/通讯作者在环境及水处理领域权威期刊发表研究论文4篇，申请国家发明专利5项，其中1项获授权。