模拟降雨下土壤中黄钾铁矾对锑的固持效应研究  

Antimony retention characteristics of jarosite in soil under simulated rainfall

作　　者：冉毅媛 李学先[1,2] 李玲 吴攀 RAN Yiyuan;LI Xuexian;LI Ling;WU Pan(College of Resources and Environmental Engineering,Guizhou University,Guiyang 550025;Key Laboratory of Karst Georesources and Environment,Ministry of Education,Guiyang 550025;State Key Laboratory of Environmental Geochemistry,Institute of Geochemistry,Chinese Academy of Sciences,Guiyang 550081)

机构地区：[1]贵州大学资源与环境工程学院,贵阳550025 [2]喀斯特地质资源与环境教育部重点实验室(贵州大学),贵阳550025 [3]中国科学院地球化学研究所环境地球化学国家重点实验室,贵阳550081

出　　处：《环境科学学报》2024年第9期347-355,共9页Acta Scientiae Circumstantiae

基　　金：贵州省科技计划项目(No.黔科合支撑[2022]一般222;黔科合平台人才-GCC[2023]045);国家重点研发计划(No.2020YFC1807601)。

摘　　要：锑矿采冶常导致周边土壤及水体中锑(Sb)的污染,控制污染物Sb向水土环境中迁移对当地的生态环境保护至关重要.黄钾铁矾是一种羟基硫酸盐铁矿物,广泛存在于富含硫酸盐的酸性氧化环境中,对重(类)金属有较好的固定作用.以贵州省Sb矿冶炼厂周边受Sb污染的土壤为研究对象,通过模拟降雨条件下的土柱实验,探究污染土壤剖面中Sb在垂向上的迁移转化特征以及黄钾铁矾对污染土壤中Sb的固持效果.结果表明:降雨前期(0~50 h),有黄钾铁矾土柱中Sb的溶出浓度为20μg·L^(-1),远低于无黄钾铁矾土柱(70μg·L^(-1)),黄钾铁矾对Sb的固持效率达到71.4%.模拟降雨后,土壤Sb在土柱剖面发生了垂向迁移,但无黄钾铁矾土柱在5 cm处Sb含量达71.4 mg·kg^(-1),可提取态Sb(可提取态Sb指Wenzel提取法得到的非专性吸附态(F1)+专性吸附态(F2)+无定型铁铝氧化物结合态(F3)+结晶铁铝氧化物结合态(F4))占比较高,Sb有向深层土壤迁移的趋势;而有黄钾铁矾土柱4 cm处Sb含量即达到75.3 mg·kg^(-1),而6 cm处降低为17.2 mg·kg^(-1),可提取态Sb随着土壤深度的增加向更稳定的赋存形态(残渣态(F5))转化,6 cm处可提取态Sb的转化比率达到55.3%,说明黄钾铁矾矿物的添加对Sb的迁移起到固持效果.XPS结果显示,有黄钾铁矾土柱中Fe(II)促进了Fe‒O‒Sb键的形成,使Fe 2p3/2峰向更高的结合能位点偏移,更接近Fe-Sb共沉淀的结合能位点,土壤中出现Fe-Sb的结合.同时,降雨50 h后,雨水在土柱表层蓄积,Sb溶出浓度增加,表明土壤条件的改变可影响黄钾铁矾的固持效果.Antimony(Sb)pollution in the surrounding soil and water is often caused by the mining and smelting area.It is very important to control the migration of Sb to soil and water environment for local ecological environment protection.Antimony mining often leads to antimony(Sb)pollution in the surrounding soil and water.It is crucial to control the migration of Sb into soil and water environment for local ecological environment protection.Jarosite is a kind of hydroxyl sulfate iron mineral,which exists widely in acidic oxidation environment rich in sulfate,and has good fixation effect on heavy metals.Taking the soil contaminated by antimony around the Sb mine smelter in Guizhou Province as the object.The vertical migration and transformation characteristics of Sb in contaminated soil profile and the retention effect of jarosite on Sb in polluted soil are investigated by soil column experiments under simulated rainfall conditions.The results show that,in the early period of rainfall(0~50 h),the dissolution concentration of Sb in the column was 20μg·L^(-1),much lower than that in the column without jarosite(70μg·L^(-1)),and the holding efficiency of Sb by jarosite reaches 71.4%.After simulated rainfall,the vertical migration of Sb occurred,however the content of Sb reached 71.4 mg·kg^(-1)at 5cm in the column without jarosite.The extractable Sb(refers to the non-specifically sorbed(F1)+specifically-sorbed(F2)+amorphous and poorly-crystalline hydrous oxides of Fe and Al(F3)+well-crystallized hydrous oxides of Fe and Al(F4)by Wenzel extraction method)accounted for a relatively high proportion,and Sb had a tendency to migrate to deep soil.In the jarosite column,Sb content reached 75.3 mg·kg^(-1)at 4cm,and decreased to 17.2 mg·kg^(-1)at 6 cm.The extractable Sb transformed to a more stable occurrence form(residual state(F5))with the increase of soil depth,and the conversion ratio of extractable Sb at 6 cm reached 55.3%,indicating that the addition of jarosite minerals had a stabilizing effect on the migration of Sb.X

关 键 词：锑(Sb) 黄钾铁矾 模拟降雨 迁移转化 

分 类 号：X131.3[环境科学与工程—环境科学]