Laboratory Study on Chemical Leaching Remediation of Heavy Metal Contaminated Soil
A heavy metal contaminated plot in Hongkou District of Shanghai was studied.The eluent of choice is hydrochloric acid,citric acid,oxalic acid,succinic acid and EDTA solution.The effects of different eluent types,eluent concentration,water and soil ratio and eluent duration on eluent removal rate were studied.The experimental results showed that the concentration of citric acid was 0.5～2.0 mol/L,the ratio of soil to water was 1 ∶ 10～1 ∶ 15,and the leaching time was 4～6 h.The concentrations of four heavy metals after leaching were all lower than the repair target value.From the economic point of view,it is recommended to use 0.5 mol/L citric acid as leaching agent,soil-water ratio of 1 ∶ 10,leaching time of 4 h,and leaching times of 1 time.The pH value of the soil can be adjusted to the range of 6～9 when the proportion of quick lime is 1.5%.The leaching wastewater is treated with the combination of 7%PAC and 1‰PAM as flocculant,and the effluent COD concentration can meet the discharge standard.
heavy metal contaminated soilchemical leaching repairlaboratory test
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