A batch experiment was conducted to study the effect of
calcium carbonate on the adsorption and desorption of Cd in three
kinds of soils.The solution of different Cd concentrations prepared with CdCl 2 was equilibrated with soil samples by shaking for 12 hours and 1mol/L KNO 3 was used to extract the exchangeable Cd.The effect of
calcium carbonate was investigated by removal of calcium carbonate (by 0.5mol/L pH5.0 NaAc HAc) in castanozem soil and by adding of calcium carbonate (1.0%) to leached cinnamon soil,brown earth and castanozem soil,respectively.The results showed that (1) the total amounts of Cd adsorption and specific Cd adsorption were increased in the following order:leached cinnamon soil
leached cinnamon soil>castanozem soil.The capacity of Cd desorption significantly was decreased by adding CaCO 3 to soils.(6) The removal of CaCO 3 from castanozem soil could lower both adsorption capacity and the amount of specific Cd adsorption,but increased the Cd desorption markedly.