共存离子对EK/PRB联合修复砷污染土壤的影响  

Interference of coexistence ions on arsenic removal from soil by electrokinetic process coupled with permeable reaction barrier

作　　者：纪冬丽 张竞[2] 孟凡生[3] 王业耀[4] 

机构地区：[1]天津城建大学环境与市政工程学院,天津300384 [2]天津地质调查中心,天津300170 [3]中国环境科学研究院,北京100012 [4]中国环境监测总站,北京100012

出　　处：《环境工程学报》2018年第1期172-177,共6页Chinese Journal of Environmental Engineering

基　　金：国家自然科学基金资助项目(51308520)

摘　　要：以砷含量为500 mg·kg^(-1)的模拟土壤为研究对象,采用电动/渗透性反应格栅(EK/PRB)联合技术对土壤中的砷进行去除。研究土壤共存离子Fe^(3+)、Ca^(2+)、Al^(3+)、HCO_3^-、NO_3^-和PO_4^(3-)等的影响下电流密度、土壤pH分布、砷残余量的变化,重点研究土壤中不同形态砷之间的迁移转化规律。结果表明:添加共存离子后,土壤砷残余量增加,去除效率降低,由68%降低到41%;土壤电流密度变化幅度增加,由3 mA·cm^(-2)在24 h后升高到9.5 mA·cm^(-2),然后在12 h内迅速下降,最后稳定在0.6 mA·cm^(-2);pH变化幅度增加,变化趋势未发生变化,均是靠近阴极侧呈碱性,靠近阳极侧呈酸性;土壤中砷残渣态由11.98%升高到39.81%,残渣态的升高是土壤中砷去除率降低的原因。Simulated contamination soil containing 500 mg·kg-1 arsenic was employed to study the removal of arsenic in soil by electrokinetie process coupled with permeable reaction barrier （EK/PRB）. The influence of the soil coexisting ions（ Fe3＋ , Ca2＋ ,A13＋ , HCO3- , NO3- and PO4 3- ） on the variation of current density, the distri- bution of soil pH and arsenic residual quantity, mainly on the arsenic migration transformation, were investiga- ted. The results showed that the soil arsenic residual quantity increased and the removal efficiency decreased from 68% to 41% . Soil current density increased from 3 mA·cm-2 to 9.5 mA·cm-2 in 24 h, then dropped -2 rapidly within 12 h, finally stabled in 0.6 mA· cm A general trend of low pH near the anode and high pH near the cathode was found. The coexistence of ions increased the residual arsenic content from 11.98% to 39.81% , which resulting in the lower arsenic removal efficiency. The results reported in the present work will provide important theoretical support to optimizing design of EK/PRB for the removal of arsenic in the soil.

关 键 词：共存离子 砷形态 迁移转化 土壤 电动/渗透性反应格栅(EK/PRB) 

分 类 号：X53[环境科学与工程—环境工程]