超声波强化电动-膨润土吸附处理土壤镉污染的研究  

Remediation of Cadmium Contaminated Soil by Using Ultrasonic Enhanced on Electrokinetic and Adsorption of Bentonite

作　　者：侯素霞[1] 王亭 雷旭阳 HOU Suxia;WANG Ting;LEI Xuyang(Department of Resource and Environmental Engineering,Xingtai Polytechnic College,Xingtai 054000 China;Department of Chemistry,College of Science,Hebei North University,Zhangjiakou 075000,China)

机构地区：[1]邢台职业技术学院资源与环境工程系,河北邢台054000 [2]河北北方学院理学院化学系,河北张家口075000

出　　处：《生态环境学报》2020年第8期1675-1682,共8页Ecology and Environmental Sciences

基　　金：河北省科技支撑计划项目(17274206)。

摘　　要：电动修复和吸附技术广泛应用于土壤中重金属镉的去除。为提高电动修复土壤镉污染的去除效率、解决修复过程中引起的土壤pH突变、降低处理成本,该研究将超声波强化与电动力修复-吸附技术结合起来。实验结果表明:钠基膨润土是一种非常良好的吸收材料,对重金属镉具有很强的吸附特性,吸附速率非常快,一般35 min就能吸附完成。在电动修复处理过程中采用的电场强度、土壤的pH值是影响镉去除效果的主要因素,电压强度1 V·cm^−1,每隔2 d周期切换电极条件下,镉的去除率能达到69.5%;最终处理结束后,土壤pH值仅比初始值略有降低。进一步实验表明,超声波强化后能显著提高电动-膨润土吸附修复装置对镉的去除率,在同样电压强度1 V·cm^−1、超声波装置功率100 W条件下,土壤中的镉具有更高的去除率,能达到84.8%,比不施加超声波强化时镉的去除率提高了15.3%,并在一定程度了节约了能耗;超声波强化电动-膨润土吸附联合修复技术,不使用有机酸等化学淋洗剂,基本保持原有土壤环境,是一种对环境友好的原位土壤重金属镉去除技术。Electrokinetic and adsorption remediation technologies were used for removal of Cd in soil.The study aimed at how to enhance the removal of Cd by using ultrasonic-electrokinetic-adsorption of bentonite in order to solve the soil pH mutation caused by the remediation process and reduce the treatment cost.The results showed that sodium bentonite was a good material adsorption for Cd which had very strong adsorption on Cd in a short time(less than 35 min).A series of laboratory experiments involving different electric field intensity and pH value were carried out for perching the best removal rate of cadmium.Under the conditions of voltage gradient of 1 V·cm^−1,polarity reversal cycle of two days and ultrasonic power of 100 W,the removal rate of cadmium could reach to 69.5%.After the final reaction,the pH value of soil decreased slightly.The synergetic application of ultrasonic-electrokineticadsorption for the removal of Cd was demonstrated to be most effective,which could increase the removal rate of Cd,in the further experiments compared with no ultrasonic-enhanced.With the same voltage gradient of 1 V·cm^−1,polarity reversal cycle of two days and ultrasonic power of 100 W,the cadmium in soil could be wiped off in high efficiency(removal rate 84.8%),which could improve the removal rate of 15.3%than without ultrasonic and reduce energy consumption.It is a kind of environmental friendly in-situ removal technology for removal of cadmium in soil with ultrasonic-enhanced on electrokinetic-adsorption of sodium bentonite,which can maintain the original soil environment,without using organic acid and other chemical leaching.

关 键 词：超声波强化 电动力-吸附 镉 土壤污染 

分 类 号：X53[环境科学与工程—环境工程]