[Comparison on desorptive behavior of copper in phaeozem and burozem]

Desorptive behavior of Cu2+ from phaeozem and burozem was studied and compared using the batch method. The results indicated that Cu2+ desorbed from phaeozem tested had a longer lag period than that from burozem. When adsorbed Cu2+ for phaeozem was lower than 729.00 mg x kg(-1) (Cu2+ concentration was lower than 40 mg x L(-1)), and on burozem was lower than 393.29 mg x kg(-1) (Cu2+ concentration was lower than 20 mg x L(-1)), adsorbed Cu2+ was hardly desorbed. Meanwhile, the desorption ratio of Cu2+ from the two soils were both low, especially for phaeozem. In the range of Cu2+ concentration used in the experiments, the desorption rate maximums of Cu2+ for phaeozem and burozem were respectively 6.60% and 13.56%. Freundlich equation could best describe desorption isotherm processes of Cu2+ from the two soils. Adsorbed Cu2+ on soils was desorbed so fast from phaeozem and burozem that the desorption equilibrium could be reached only after 40 min desorption. The best model to describe Cu2+ desorption kinetics was two-constant equations, followed by the Elovich equation.