沉积物岩性及水化学性质对水土界面氟迁移行为的影响  

Effects of Sediment Lithology and Groundwater Hydrochemical Characteristics on Fluorine Transport at Water-Soil Interface

作　　者：朱亚鹏[1] 苏春利[1] 梁川 向鸿燕 

机构地区：[1]中国地质大学环境学院,武汉430074 [2]湖北省地质环境总站,武汉430034

出　　处：《地质科技情报》2015年第5期160-165,共6页Geological Science and Technology Information

基　　金：国家高技术发展计划(863计划)项目(2012AA062602)

摘　　要：水土界面氟的迁移对高氟地下水的形成具有重要影响。以大同盆地典型氟中毒区为例,分析了不同岩性沉积物中的氟质量分数和形态分布特征,并通过室内静态实验,探究了水溶液的pH值、Ca2+、HCO-3以及H2PO-4质量浓度对水土界面氟迁移的影响。研究结果表明,沉积物中不同形态氟按含量由高到低的顺序依次为:残余态氟铁锰氧化态氟>水溶态氟>有机束缚态氟>离子交换态氟;各形态氟在不同岩性沉积物中含量大小均表现为:黏土>粉质黏土>粉砂;在沉积物中,黏土矿物和方解石是主要的固氟矿物成分。溶液的pH值、Ca2+、HCO-3以及H2PO-4质量浓度与氟在沉积物表面的吸附-解吸和沉淀-溶解平衡密切相关,沉积物对氟的吸附量随溶液pH值和HCO-3质量浓度增大而降低,随Ca2+和H2PO-4质量浓度增大而增大。Fluorine transport at water-soil interface affects formation of high fluoride groundwater. High fluoride groundwater occurring in Datong Basin is a serious problem, which is typical in China. In this pa- per, efforts were made to analyse the distributional characteristics of fluorine content and fluorine forms in the sediments of different lithologies, and to investigate the influence of pH, Ca2＋ , HeO3- and H2PO4 on fluorine transport at water-soil interface using static experiments. The results show that contents of differ- ent fluorine forms in sediments descended in the following sequence： residual F 〉Fe/Mn oxide-F〉water soluble F〉organic F〉exchangeable F. The order of fluorine contents in the aforementioned forms in dif- ferent lithologies is. clay〉silty clay〉silt, in which clay minerals and calcite are main fixed fluorine miner- als in sediments. In addition, the solution pH value and the concentrations of Ca2＋ , HCO3- and H2PO4- are closely related to adsorption-desorption and dissolution-precipitation equilibrium of fluorine on the surface of sediments. The adsorption capacity of sediments on fluorine decreases with increasing pH and HCO3- concentration, but increases with the concentration of Ca2＋ and H2PO4.

关 键 词：氟 沉积物 水化学特征 迁移 

分 类 号：P641[天文地球—地质矿产勘探]