缺氧酸性条件下三价铁对锑释放的作用机制  

Mechanism of action of Fe(III)on antimony release under anoxic acidic conditions

作　　者：唐雅宁 王兴华 王英男 李小倩[2] 宋晓东 TANG Yaning;WANG Xinghua;WANG Yingnan;LI Xiaoqian;SONG Xiaodong(Institute of Geological Survey,China University of Geosciences(Wuhan),Wuhan,Hubei 430074,China;School of Environmental Studies,China University of Geosciences(Wuhan),Wuhan,Hubei 430074,China;Land Consolidation and Rehabilitation Center,MNR,Beijing 100035,China)

机构地区：[1]中国地质大学(武汉)地质调查研究院,湖北武汉430074 [2]中国地质大学(武汉)环境学院,湖北武汉430074 [3]自然资源部国土整治中心,北京100035

出　　处：《水文地质工程地质》2023年第6期175-183,共9页Hydrogeology & Engineering Geology

基　　金：国家重点研发计划项目(2022YFC3702201);国家自然科学基金项目(41672245)。

摘　　要：辉锑矿(Sb_(2)S_(3))的氧化溶解是控制锑(Sb)从岩矿中释放进入水土环境并影响其迁移转化的首要过程。酸性矿山废水中的三价铁[Fe(Ⅲ)]是矿区环境中广泛存在的天然氧化剂,然而Fe(Ⅲ)对Sb_(2)S_(3)的氧化溶解与Sb的释放作用机制尚不明确。通过模拟黑暗缺氧酸性的矿山地下水环境,开展Fe(Ⅲ)浓度与Sb_(2)S_(3)表面积比值(Ⅰ)控制的Sb_(2)S_(3)氧化溶解动力学实验,结合S-Sb-Fe氧化还原作用产物的溶解态组成与固相表征手段,揭示Fe(Ⅲ)对Sb释放的作用机制。结果显示:Fe(Ⅲ)作用下Sb_(2)S_(3)的氧化溶解是一个产酸的过程,Ⅰ值越大,Fe(Ⅲ)对Sb释放的促进作用越明显。缺氧条件下,Fe(Ⅲ)与Sb_(2)S_(3)发生氧化还原作用,主要产物是五价锑[Sb(V)]、硫单质[S(0)]和二价铁[Fe(Ⅱ)],反应后矿物表面有S(0)和Fe_(2)O_(3)检出,阻碍了Sb_(2)S_(3)氧化溶解反应的持续进行。Ⅰ值一定时,低浓度的Fe(Ⅲ)和溶解氧(DO)质量浓度的增加均会减少矿物表面S(0)的附着量,促进Sb释放量的增加;溶液中的Cl-通过配位络合效应会促进Sb_(2)S_(3)的溶解释放。缺氧酸性条件下Fe(Ⅲ)与Sb_(2)S_(3)的作用控制着Sb的释放。研究结果可为矿山闭坑后地下水Sb污染防治提供重要的理论依据。Oxidative dissolution of stibnite(Sb_(2)S_(3))is the primary process that controls the release of antimony(Sb)from rock and ore into the soil and water environment and affects its transport and transformation.Fe(III)in acid mine wastewater is a widespread natural oxidant in the mine environment.However,the role of Fe(III)on the oxidative dissolution of Sb_(2)S_(3)and Sb release is unknown.By simulating a dark anoxic and acidic mine groundwater environment,this study conducted Fe(III)concentration to Sb_(2)S_(3)surface area ratio(I)controlled Sb_(2)S_(3)oxidative dissolution kinetics experiments,and combined the dissolved state composition and solid phase characterization means of S-Sb-Fe redox products to reveal the mechanism of Fe(III)action on Sb release.The results show that the oxidative dissolution of Sb_(2)S_(3)under the action of Fe(III)is an acid-producing process,and the larger the I value is,the more obvious the promotion effect of Fe(III)on Sb release.Under anoxic conditions,Fe(III)undergoes redox with Sb_(2)S_(3),and the main products are Sb(V),S(0)and Fe(II).After the reaction,S(0)and Fe_(2)O_(3)were detected on the mineral surface,which hindered the continuation of the oxidative dissolution reaction of Sb_(2)S_(3).At a certain value of I,both the low concentration of Fe(III)and the increase of dissolved oxygen(DO)will reduce the attachment of S(0)on the mineral surface and promote the increase of Sb release;the Cl−in solution will promote the dissolution release of Sb_(2)S_(3)through the coordination complexation effect.The interaction between Fe(III)and Sb_(2)S_(3)under anoxic acidic conditions controls the release of Sb,which can provide an important theoretical basis for prevention and control of groundwater Sb contamination after mine pit closure.

关 键 词：辉锑矿 三价铁 锑释放 氧化溶解 缺氧酸性条件 矿区环境 

分 类 号：TD167[矿业工程—矿山地质测量] X523[环境科学与工程—环境工程]