Interactions between calcium phosphate and heavy metal ions in aqueous solution

Abstract

Abstract. Synthetic and natural calcium phosphates were tested for removal metallic pollution in aqueous solution. Calcium phosphates with Ca/P ratio between 1,33 and 1,67 are fluently called apatite. They have a strong capacity to immobilize metallic ions when they are brought into contact with aqueous solutions. Ca 2+ ions can substituted completely or partly by cations such as metallic ions (Ni 2+ ; Cu 2+ ; Co 2+ and Cd 2+ ). PO 3− 4 ions can be replaced by anions such as AsO 3− 4 , CO 2− 3 , . . . etc. Sorption of Cu 2+ and Ni 2+ from aqueous solutions on natural (NA) and synthetic (SA) apatite was investigated in batch mode at 25 • C and 40 • C and over metal concentration range of 20-800 mg/L. Other experiments of co-precipitation metal-apatite (metal-TCP) were investigated in static mode at 25 • C. The results characterization of NA and SA apatite by FTIR, SEM, and ICP confirm their composition and apatitic structure. The results confirm efficiency of these calcium phosphates to decontaminate, by adsorption or co-precipitation, metallic ions such as Ni 2+ or Cu 2+ present in aqueous solution at concentrations between 20-800 mg/L.

Synthesis of magnetic calcium phosphate composites using citric acid as additive for removal of cadmium from aqueous solution

“…Calcium phosphates (CPs) materials have received a lot of attention in the field of waste treatment [4][5][6][7][8][9][10][11][12][13][14][15]. CPs have many advantages, such as availability, low water solubility, non-toxicity, low cost, and high ability for metals uptake.…”