Effects of EDTA and Organic Acids on Cd Desorption from Zhangshi Irrigation Area Soil

The effects of the added EDTA and organic acids (oxalic acid, tartaric acid and acetic acid) on Cd desorption of Zhangshi Irrigation Area (ZIR)contaminated soil of Shenyang city was investigated by batch balance experiments, in which the concentrations of acids, pH and temperature were examined. The results showed that EDTA, oxalic acid, tartaric acid and acetic acid modified the desorption behaviors of Cd. And the desorption level was EDTA>tartaric acid >oxalic acid >acetic acid. Also, the desorption amount of Cd increased with the concentration ranges from 5 to 40mmol/L; the desorbed amount obviously reduced with elevating pH when the pH was below 6; the adsorption was facilitated and the desorption was weakened when the pH was above 6. In addition, the Cd desorption amount raised with the temperature increasing.