HYDROXYAPATITE COMPOSITE FOR USE IN REMOVAL OF CONTAMINANTS FROM EFFLUENTS AND METHODS OF MAKING

A composite comprising a hydroxyapatite and at least one additive which is present during hydroxyapatite synthesis. The additive may be embedded or incorporated into or coated onto the hydroxyapatite. The additive preferably increases the hydroxyapatite porosity, e.g., providing a higher pore volume and/or BET surface area than a hydroxyapatite material without additive. The additive preferably comprises an activated carbon, chitosan, hopcalite, clays, zeolites, sulfur, and/or a metal such as Al, Sn, Ti, Fe, Cu, Zn, Ni, Cu, Zr, La, Ce, in the form of metal, salt, oxide, oxyhydroxide, and/or hydroxide. The hydroxyapatite may be calcium-deficient. The composite is in the form of particles having a D50 of at least 20 μm, a BET surface area of at least 120 m2/g; and/or a total pore volume of at least 0.3 cm3/g. An adsorbent material comprising a composite or a blend of composite with a hydroxyapatite without additive, and its use for removal of contaminants such as Hg, Se, As, and/or B from an effluent.