Hydroxy- and fluorapatite as sorbents in Cd(II)-Zn(II) multi-component solutions in the absence/presence of EDTA

► Apatites are effective sorbents to remove Cd2+ and Zn2+ in multi-component solution. ► Competitive metal sorption reduces the individual amounts of metal ions removed. ► The complexation of metal ions with EDTA inhibits their sorption on apatites. ► XPS proofs the formation of Ca2+ and Zn2+-substituted surface layer by ion exchange. ► Composition of new surface layer on apatite is Ca8.4−xMex(HPO4)1.6(PO4)4.4(OH)0.4.