地下水排泄河水过程中溶解态铁砷的协同迁移转化机制  

Co-Migration and Transformation Mechanism of Dissolved Iron and Arsenic during Groundwater Discharge into River Water

作　　者：邓茜予 刘慧[1,2] 黄瑶 Deng Xiyu;Liu Hui;Huang Yao(School of Environmental Studies,China University of Geosciences,Wuhan 430078,China;State Key Laboratory of Biogeology and Environmental Geology,Wuhan 430078,China)

机构地区：[1]中国地质大学环境学院,湖北武汉430078 [2]中国地质大学生物地质与环境地质国家重点实验室,湖北武汉430078

出　　处：《地球科学》2024年第7期2627-2636,共10页Earth Science

基　　金：国家自然科学基金重点项目(No.41830862)。

摘　　要：地下水排泄河水过程中会将缺氧地下水中的Fe^(2+)与As^(3+)带入含氧的交互带中,本研究旨在探明该过程中Fe^(2+)与As^(3+)随地下水在实际沉积物介质中的协同迁移转化机制.通过室内柱实验和批实验研究地下水排泄河水时Fe^(2+)、As^(3+)的迁移转化规律并获取其在交互带不同部位向固相转化(固化)的速率.结果表明:沉积物对Fe^(2+)、As^(3+)具有较强的吸附作用,As^(3+)加快了Fe^(2+)的迁移;Fe^(2+)在流经交互带时发生化学氧化沉淀,形成了Fe-As结合态矿物.从远河处至近河处河处,Fe^(2+)、As^(3+)的固化速率加快.在整个交互带区域Fe^(2+)明显促进了As^(3+)的固化,在离河较近的区域As^(3+)略微抑制了Fe^(2+)的固化.地下水排泄河水过程中,Fe^(2+)、As^(3+)在交互不同部位以不同的速率发生协同化学氧化和吸附固定,从而严重阻碍其向河水方向迁移.During groundwater discharge into the river,Fe^(2+)and As^(3+)in anoxic groundwater are brought into the oxygencontaining interaction zone.This study explores the co-migration and transformation mechanism of Fe^(2+)and As^(3+)with groundwater in the natural sediment medium.The migration and transformation rules of Fe^(2+)and As^(3+)during groundwater discharge into river water and the transformation rate of Fe^(2+)and As^(3+)to solid phase(solidification)in different regions of the interaction zone are studied by laboratory column experiment and batch experiment.The results show that the sediment strongly adsorbs Fe^(2+)and As^(3+),and As^(3+)accelerates the migration of Fe^(2+).The chemical oxidation and precipitation of Fe^(2+)occur,and Fe-As bounding minerals are formed when it flows through the interaction zone.The solidification rate of Fe^(2+)and As^(3+)is accelerated from the area far from the river to that near the river.In the whole interaction zone,Fe^(2+)significantly promotes the solidification of As^(3+),while As^(3+)slightly inhibits the solidification of Fe^(2+)near the river bank.In short,during groundwater discharge into river water,the synergistic chemical oxidation and adsorption fixation of Fe^(2+)and As^(3+)in groundwater occur at different rates in different regions of the interaction zone,which seriously hinders their migration to river water.

关 键 词：地下水排泄 交互带 铁 砷 迁移 水文地质 

分 类 号：P641.2[天文地球—地质矿产勘探]