The sorption of copper on synthetic hydroxyapatite was investigated using a batch method and radiotracer technique. The hydroxyapatite
sample prepared by a wet precipitation process was of high crystallinity with Ca/P ratio of 1.688. The sorption of copper
on hydroxyapatite was pH independent ranging from 4 to 6 as a result of buffering properties of hydroxyapatite. The adsorption
of copper was rapid and the percentage of Cu sorption was >98% during the first 15–30 min of the contact time. The experimental
data for sorption of copper have been interpreted in the term of Langmuir isotherm. The sorption of Cu2+ ions was performed by ion-exchange with Ca2+ cations on the crystal surface of hydroxyapatite under experimental conditions. The competition effect of Zn2+, Fe2+ and Pb2+ towards Cu2+ sorption was stronger than that of Co2+, Ni2+ and Ca2+ ions. The ability of the bivalent cations to depress the sorption of copper on hydroxyapatite was in the following order
Pb2+ > Fe2+ > Zn2+ > Co2+ ≈ Ni2+.