海泡石改性土-膨润土泥浆阻截墙阻截地下水重金属阳离子污染  

Sepiolite Modified Soil-Bentonite Slurry Barrier Wall Cut-off Heavy Metal Cation Pollution in Groundwater

作　　者：赵勇胜 戴贞洧[1] Zhao Yongsheng;Dai Zhenwei(College of New Energy and Environment,Jilin University,Changchun 130021,China;National Local Joint Engineering Laboratory of Petrochemical Pollution Site Control and Remediation Technology,Jilin University,Changchun 130021,China)

机构地区：[1]吉林大学新能源与环境学院,长春130021 [2]吉林大学石油化工污染场地控制与修复技术国家地方联合工程实验室,长春130021

出　　处：《吉林大学学报（地球科学版）》2023年第5期1549-1559,共11页Journal of Jilin University：Earth Science Edition

基　　金：国家自然科学基金项目(42072270)。

摘　　要：为探究海泡石的添加对土-膨润土泥浆阻截墙材料的施工和易性、渗透性,以及对地下水重金属阳离子污染阻截性的影响,采用天然海泡石对土-膨润土泥浆阻截墙改性,并以铅污染为代表,进行了坍落度实验、渗透实验和吸附实验。结果表明:添加海泡石不会对土-膨润土-海泡石阻截材料施工和易性造成太大影响,海泡石掺量从0增加至30%,满足目标坍落度要求的含水率仅增加1%;在实验掺量范围内海泡石对泥浆阻截材料渗透性能的影响较小,材料渗透系数均小于10^(-7)cm/s,能够满足工程要求;材料对Pb^(2+)的吸附是以化学吸附为主的吸附过程,海泡石掺量分别为0、5%、10%和20%时,泥浆阻截材料对Pb^(2+)的吸附量依次为89.73、112.52、140.85、183.40 mg/g,温度降低,阻截材料吸附量也随之减少。在铅污染液的作用下,土-膨润土-海泡石阻截材料渗透系数逐渐上升,海泡石的存在能够延缓Pb^(2+)对该阻截材料的侵蚀;渗出液pH和Pb^(2+)质量浓度变化表明,在实验时间内阻截材料仍然起着阻截作用。In order to investigate the effect of sepiolite addition on the construction workability and permeability of soil-bentonite slurry barrier wall,as well as the retardance of heavy metal cation contamination in groundwater,natural sepiolite was used to modify the soil-bentonite slurry barrier wall.Lead was used as a representative contaminant and slump,permeability and adsorption tests were carried out.The results show that the addition of sepiolite not has much impact on the construction workability of the soil-bentonite-sepiolite barrier material.Increasing the sepiolite dosage from 0 to 30% increases the optimum water content of the barrier material by only 1% when meeting the target slump requirement.Sepiolite has little effect on the permeability performance of the slurry barrier material in the experimental dosage range,and the permeability coefficients of the materials are less than 10^(-7)cm/s,which can meet the engineering requirements.The adsorption of Pb^(2+)by the soil-bentonite-sepiolite material is an adsorption process dominated by chemical adsorption,and the adsorption amount of Pb^(2+)by the material was 89.73,112.52,140.85,183.40 mg/g in the order of 0,5%,10%,and 20% of sepiolite doping,and the adsorption amount was reduced when the temperature was decreased.Under the corrosion of Pb^(2+),the permeability coefficient of the soil-bentonite-sepiolite barrier material gradually increases,but the presence of sepiolite can delay the corrosion of Pb^(2+)to the barrier material.Changes in pH and lead mass concentration of the exudate indicate that the soil-bentonite-sepiolite barrier material still acts as a blocking material during the experimental time.

关 键 词：泥浆阻截墙 海泡石 土-膨润土 地下水重金属污染 污染物侵蚀 

分 类 号：X523[环境科学与工程—环境工程] TU411.4[建筑科学—岩土工程]