铬污染土壤电动修复过程中典型阴离子的迁移特征  

Migration characteristics of typical anions in the process of electrokinetic remediating Cr(Ⅵ)-contaminated soil

作　　者：张开轩 罗泽娇[1] ZHANG Kaixuan;LUO Zejiao(School of Environmental Studies,China University of Geosciences(Wuhan),Wuhan 430074,China)

机构地区：[1]中国地质大学(武汉)环境学院,武汉430074

出　　处：《环境工程学报》2020年第12期3515-3526,共12页Chinese Journal of Environmental Engineering

基　　金：湖北省技术创新专项(2017ACA092)。

摘　　要：为揭示典型阴离子在电动修复六价铬污染土壤过程中的迁移行为,以人工配置的Cr(Ⅵ)污染蒙脱石模拟供试土壤,蒸馏水作为阴阳极电解液,在电压梯度为2 V·cm^−1的条件下进行电动修复实验;并分别对比分析各组实验的电流、pH、电导率、能量损耗参数的变化。结果表明,5种阴离子在土壤电动修复过程中的迁移顺序为:NO3^−>Cr(Ⅵ)≈Cl^−>SO4^2−≫PO4^3−NO3^−>Cr(Ⅵ)≈Cl^−>SO4^2−≫PO4^3−。相比于酸性土壤,偏中性的土壤环境更利于Cr(Ⅵ)向阳极的迁移,而酸性土壤会导致电动修复过程能耗的增加,更容易产生聚焦现象。土壤中CO3^2−CO3^2−、OH^−和PO4^3−PO4^3−的存在,能有效地缓解电动修复过程中产生的聚焦现象,而且能加速土壤中Cr(Ⅵ)的去除;PO4^3−PO4^3−的存在能将Cr(Ⅵ)的去除率提高到99.9%以上。本研究结果可为电动修复六价铬污染土壤电解液的选择提供参考。The electrokinetic remediation technology for contaminated soil is a hot topic in the field of environmental engineering around the world.But the existence of a large amount of free-migrating ions in soil increases its energy consumption and limits its application.In order to disclose the migration behavior of typical anions in the process of electrokinetic remediating Cr(Ⅵ)-contaminated soil,the synthetic Cr(Ⅵ)-contaminated montmorillonite was used to simulate the contaminated soil,and the deionized water was taken as the electrolytes,NO3^−NO3^−,Cl^−,OH^−,SO4^2−SO4^2−,CO3^2−CO3^2−and PO4^3−PO4^3−were taken as typical anions,the electrokinetic remediation experiments were conducted at voltage gradient of 2 V·cm^−1.The changes in current,pH,conductivity,energy consumption of each experimental group were compared and analyzed.The results showed that the migration priority of the anions in the soil was NO3^−>Cr(VI)≈Cl^−>SO4^2−≫PO4^3−NO3^−>Cr(VI)≈Cl^−>SO4^2−≫PO4^3−.In comparison with acidic soil,neutral soil accelerated the migration of Cr(Ⅵ)to the anode,while acid soil could lead to the increase of energy consumption during electrokinetic remediation process,even easily caused the focusing effect.The existence of CO3^2−CO3^2−,OH^−and PO43^−PO4^3−in soil could effectively alleviate the focusing effect,and also accelerate the removal of Cr(Ⅵ).The existence of PO4^3−PO4^3−could increase the Cr(Ⅵ).removal rate above 99.9%.The result of this research can provide a reference for electrolyte selection in the process of electrokinetic remediating Cr(Ⅵ)-contaminated soil.

关 键 词：污染土壤修复 电动修复 阴离子迁移 离子迁移行为 

分 类 号：X53[环境科学与工程—环境工程]