Study On The Combined Remediation Of Heavy Metal Cr In Soil By Ion Exchange Resin And Electrokinetic

With the development of industry and agriculture,the problem of soil pollution is becoming more and more serious,so it is necessary to develop a soil pollution removal technology that can develop for a long time.Among many soil pollution problems,soil heavy metal pollution is the most difficult one,among which chromium（Cr）pollution is more representative.At present,there are many methods for the treatment of Cr-contaminated soil,among which the electrokinetic method stands out among many methods because of its environmental friendliness and simple and safe operation.In this paper,the electrokinetic method was used as the basis to treat Crcontaminated soil with ion exchange resin,and the effects of different initial p H value of electrolyte,voltage gradient and resin dosage on soil physicochemical properties during electrokinetic treatment,as well as the removal effect and distribution of soil Cr were investigated.The results of the study are as follows:（1）The optimal electrolysis time was discussed,taking into account the change of the p H value of the cathode and the anode,the removal effect of Cr,the current intensity and the electrode consumption.The advantage of the study over other electrolysis methods is that it has a better repair effect in a shorter electrolysis cycle.（2）The effects of initial electrolyte p H,voltage gradient and resin dosage on soil physicochemical properties and device system were discussed.The results showed that the soil p H value increased with the increase of the initial electrolyte p H value and the voltage gradient,and the resin dosage had little effect on the soil p H value.The increase of resin dosage will reduce the soil conductivity and water content,and the increase of the voltage gradient will increase the soil conductivity and water content.The change of the resin dosage has little effect on the system current,while the change of the voltage gradient and the initial p H value of the electrolyte has a more obvious effect on the system current.（3）The effects of initial electrolyte p H,voltage gradient and resin dosage on the distribution and removal rate of total Cr and Cr（Ⅵ）in soil were discussed.The study found that the proportion of Cr（Ⅵ）in artificially polluted soil is relatively high,and the soil mainly exists in the form of Cr（Ⅵ）.The increase of the resin dosage will increase the total Cr removal rate.When the resin dosage is 12.5g/L,the removal rates of total Cr and Cr（Ⅵ）in the soil are the best,which are45.03% and 57.5%;The increase of voltage gradient will improve the removal rate of total Cr and Cr（VI）in soil.The removal rate of total Cr and Cr（VI）in soil is the best when the voltage gradient is 1.5V/cm,which are 37.8% and 53.9%.The p H value of the initial electrolyte has a great influence on the removal rate and distribution of total Cr and Cr（VI）,especially on the removal of Cr（VI）from the soil on the anode side;when the p H value is 4,the total Cr and Cr（VI）in the soil The removal rate of Cr（Ⅵ）reached the maximum value of 38.4% and 53.7%.