地下水环境中Mn(Ⅲ)-腐殖质胶体的形成机制  

Formation Mechanism and Characterization of Mn(Ⅲ)-Humic Ligands Colloids in Ground Water Environment

作　　者：程一涵 邓娅敏[1] 薛江凯 张余茜 Cheng Yihan;Deng Yamin;Xue Jiangkai;Zhang Yuxi(School of Environmental Studies,China University of Geosciences,Wuhan 430074,China;Geological Survey,China University of Geosciences,Wuhan 430074,China)

机构地区：[1]中国地质大学环境学院,湖北武汉430074 [2]中国地质大学地质调查研究院,湖北武汉430074

出　　处：《地球科学》2024年第2期793-802,共10页Earth Science

基　　金：国家自然科学基金面上项目(No.41977174)。

摘　　要：Mn(Ⅲ)是锰氧化还原循环中电子传递的中间体,广泛参与陆地和海洋生态系统中的碳、铁和硫的地球化学循环.近年来在厌氧、微氧和有氧水环境中陆续发现了Mn(Ⅲ)有机络合物存在,研究地下水环境中Mn(Ⅲ)-腐殖质胶体的形成机制与行为特征对于认识锰的地球化学循环及其影响的营养物和污染物的迁移转化机制具有重要意义.通过开展批实验,探讨氧气条件、腐殖质浓度和有机质种类对Mn(Ⅲ)-腐殖质胶体形成的影响,并结合FTIR、XRD、XPS、TEM多种手段表征其理化性质与稳定性.研究发现:厌氧或有氧-厌氧环境有利于Mn(Ⅲ)-腐殖质胶体形成,Mn(Ⅲ)-腐殖质的络合程度随着腐殖质浓度的升高而增强,富里酸更容易与Mn(Ⅲ)络合,但形成的胶体稳定性较Mn(Ⅲ)-胡敏酸胶体差.Mn(Ⅲ)-腐殖质胶体呈无定形形态,腐殖质上的羧基等含氧官能团与Mn(Ⅲ)形成内球络合物,可减缓Mn(Ⅲ)歧化程度.Mn(Ⅲ)-腐殖质胶体具有氧化和吸附能力,对地下水中污染物的迁移转化具有重要的环境意义.Mn(Ⅲ)is the intermediate electron transport of manganese cycling,widely involved in the terrestrial and marine ecosystems in the geochemical cycle of carbon,iron and sulfur.Recently,Mn(Ⅲ)-humic ligands colloids are found in oxide,suboxic and anoxic zone.It is of great significance to study the formation mechanism and behavior characteristics of Mn(Ⅲ)-humic colloid in groundwater environment for understanding the geochemical cycle of manganese and the migration and transformation mechanism of nutrients and pollutants affected by it.In this study,batch experiments were conducted to explore the effects of oxygen conditions,humus concentration and organic matter species on the formation of Mn(Ⅲ)-humic ligands colloids andcombined with FTIR,XRD,XPS,TEM and other means to characterize the physicochemical properties and stability.Resultsshow that suboxic and anoxic environments favor Mn(Ⅲ)-humiccolloid formation.The degree of complexation of Mn(Ⅲ)humic colloid increases with the increase of humic ligands concentration.FA is more easily complexed with Mn(Ⅲ),but the colloidal stability is worse than that of Mn(Ⅲ)-HA colloid.Furthermore,Mn(Ⅲ)-humic colloid is in an amorphous form,and oxygen-containing functional groups such as carboxyl groups on humus form an internal sphere complex with Mn(Ⅲ),which can stabilize Mn(Ⅲ)and slow down the degree of disproportionation.Mn(Ⅲ)-humic colloid has oxidation and adsorption capacity,which has important environmental significance for the migration and transformation of pollutants in groundwater.

关 键 词：Mn(Ⅲ) 腐殖质 胶体稳定性 络合机制 地下水 

分 类 号：P641[天文地球—地质矿产勘探]