Enhanced Adsorption and Transformation of Cu and Zn in Sediments by Hydroxyapatite

摘要

The adsorption and transformation characteristics of Cu and Zn in sediments with or without hydroxyapatite spiked were investigated in the present study. The isothermal adsorption results show that the hydroxyapatite enhanced the adsorption capacity of sediments and the maximum adsorption capacity of Cu and Zn increased by 70 and 150 % as compared to the sediments without hydroxyapatite spiking. The equilibrium adsorption/desorption experiment results indicate that the adsorption rates of Cu and Zn were both much more than 93 % with or without hydroxyapatite spiking. However, the hydroxyapatite obviously reduced the desorption rates of Cu and Zn from the sediments. Hydroxyapatite facilitated the transformation of Cu and Zn from less stable phases to more stable phases, especially advanced the translation of Cu and Zn from exchangeable fraction to the other fractions. These results imply that the addition of hydroxyapatite to the sediments facilitated the stability of heavy metals in the sediments and restrained the environmental risk of heavy metals to the aquatic environment to some extent.