Abstract:In order to solve the problem of soil heavy metal cadmium pollution, the desorption effects of EDTA, citric acid, glycollic acid, magnesium chloride and lauryl sodium sulfate (SDS) on cadmium-exceeding soil were studied under laboratory conditions, and the optimal removal concentration and liquid-solid ratio (L/S) of the above leaching agents were investigated, as well as the influence of the combination of several leaching agents on the elution effect of soil. The results show that the sequence of effective state cadmium removal effect is EDTA (84%) > glycollic acid (71.02%) > magnesium chloride (59.45%) > citric acid (56.69%) > SDS (11.02%). When L/S is 3, the best leaching effect is achieved. In the combination scheme, when the volume mixing ratio of EDTA and glycolic acid is 1︰2, the maximum value is 87.48%, and the volume mixing ratio of EDTA and citric acid is 1︰1, the value is 85.91%, which enhances elution effect of EDTA. When EDTA is mixed with SDS, the effect is not significantly improved. The efficiency of magnesium chloride mixed with citric acid and glycolic acid is 81.5% and 82.6% respectively, while mixed with SDS shows a slight antagonistic effect. The mixture of two kinds of acid and SDS does not increase the removal rate of heavy metals, but plays a certain role in regulating soil pH value and saving acid dosage. Based on the leaching efficiency and its influence on soil pH value, organic matter and cation exchange capacity, the best leaching efficiency is 85.91% under the conditions including L/S of 0.13 mol/L EDTA and 1 mol/L citric acid of 3 and the volume mixing ratio of 1︰1. The experimental results can provide reference for improving the desorption rate of heavy metals in soil media by combining citric acid with EDTA and magnesium chloride with two small molecular acids, and provide ideas for the treatment of contaminated soil.