Experimental Study On EK-PRB Combined Remediation On Compound Contaminated Soil Body

As a soil remediation technology with high efficiency,low-cost,EK-PRB remediation technology has been widely recognized all over the world.In this paper,laboratory-configured cadmium-cadmium-contaminated kaolin was used as experimental soil to optimize the conditions for electric repair,to determine the optimum voltage gradient,the optimal enhancement technique,and determine the best position of the PRB,which can provide theoretical guidance and technical support for the field application of EK-PRB combined technology.(1)The average removal rate of Cd increased with the increase of voltage gradients while adopting 1V/cm,2V/cm and 3V/cm as the voltage gradients for the remediation of Cr and Cd compound contaminated kaolin.Comprehensively considering the total removal rates and energy consumption,the voltage gradient of 2V/cm was adopted for follow-up experiments.(2)Tap water was used as cathode anolyt,0.1M buffer solution,0.2M buffer solution,and 0.1M citric acid solution was used as catholyte run for 7 days.Ti is found that when the concentration of cathode electrolyte was 0.1M buffer solution,the comprehensive removal rate of Cd and Cr was higher,58% and 34% respectively.(3)Tap water was used as cathode anolyte,and the exchange frequency was 1d,2d and 4d run for 8d.When the exchange frequency was 2d,the two pollutants were all enriched except those at the standard distance of 0.8 from the cathode,and the removal effects in other areas were better.In order to concentrically treat the 2d heavy metal pollutants,the fixed frequency exchange electrode intensification technology was adopted in the follow-up experiments,and the exchange frequency was 2d.(4)Under the above optimal conditions,EK-PRB Combined Remediation Technology was adopted in the experiments,and compared with single electric technology.The result showed that the EK-PRB Combined Remediation Technology with fixed-frequency exchange electrodes could effectively improve the removal rate of pollutants.The average removal rate of Cr was 72.54%,while which of Cd was 79.49%.