基于有机质来源及转化过程的高砷地下水靶向-低耗电化学净化研究

Organic matter (OM) is an important factor impacting the environmental behaviors of As in groundwater. The construction of As removal method with target and energy-efficient characteristics based on the mechanism of OM impeding the removal of As from the resource and transformation of OM was innovative. This study will analyze the structural and redox characteristics of imported OM in groundwater by tracing the source and transformation process of OM in High arsenic groundwater. Mechanism of increasing arsenic concentration in groundwater by OM from different sources will be investigated, and proportion of arsenic-containing mixture in groundwater with high arsenic content would also be clarified. Based on the activated carbon coupled with air cathode iron anodic oxidation-flocculation system, characteristics of structural and redox and proportion of arsenic-containing mixture, a new As removal system with target and energy-efficient characteristics will be constructed and improved to achieve the co-removal of As and OM in groundwater. This study primarily meets the development of the As removal technology, and the research results can provide technical support for groundwater purification with high arsenic content.

有机质是调控地下水中砷环境行为的重要因子，突破单纯地下水环境，从更为宏观的有机质来源及转化过程角度去解析有机质阻碍高砷地下水净化的机理，并据此构建高砷地下水靶向-低耗净化体系是高砷地下水净化的创新性尝试。本研究拟通过追踪高砷地下水有机质来源和转化过程，解析地下水输入性有机质组成结构特征和氧化还原特性，揭示不同来源有机质对地下水砷浓度、形态和组成比例影响。依托具有高效、低耗特性的活性炭空气阴极铁阳极氧化-絮凝除砷体系，结合高砷地下水输入性有机质组成结构、氧化还原性质以及负砷混合物组成等特征，构建高砷地下水靶向-低耗除砷体系并实施净化，基于试验结果建立有机质组成结构、负砷混合物形态组成、电化学净化参数与砷、有机质协同去除效率间的关联规律，识别主控因素，最终实现高砷地下水砷和有机质的靶向、快速、低耗协同去除。本项目符合当前高砷地下水净化科技需求，研究成果可为高砷地下水净化提供技术支持。

腐殖质是高砷地下水重要而稳定的输入性有机组分，具有电子传递能力，可以促进附砷铁、锰等矿物的还原溶解，同时腐殖酸类物质还可以与二价铁离子和污染物砷形成三元胶体物质，增加了地下水中砷的去除难度和净化成本。因此解析腐殖质类物质在砷净化过程中扮演的角色和产生的主要影响对高砷地下水净化具有重要意义，本研究通过系统研究发现，DOM中高芳香性类富里酸组分有利于As（III）的氧化净化，而其中的低芳香性类胡敏酸组分则有碍于As（III）的氧化净化，揭示在高砷地下水净化方法的选择方面，应兼顾其地球化学行为及净化机理双重特征。