Abstract:

Effects of different dosages of hydroxyapatite on the immobilization of heavy metals were studied via investigating the species distribution of heavy metals in the metalspiked sediments. The results indicate that the percentage of the heavy metals existed as residues was almost invariable, but the mass percentages of Pb,Cd and Zn tending to transform from exchangeable phase to other phases, as well as the mass percentage of Cu tending to transform from carbonate phase to other phases increased along with the increasing of applied hydroxyapatite. The percentage of Pb existed as exchangeable and carbonated phases obviously decreased with less effects on the percentages of Cd,Cu and Zn as the results of hydroxyapatite doped. 25.5%~36.1% of Pb existed as exchangeable and carbonated phases could transform to other relatively stable phases when
the ratio of P ∶M was 6.

Key words:  hydroxyapatite, sediments, heavy metals, species transformation