Research on column adsorption of Zn2+ by hydroxyapatite granules

Hydroxyapatite (HAp) granules were fabricated successfully from HAp powder and polyvinyl alcohol (PVA) additive by sintering method. The characterization of material was analyzed by color, durability in the water, XRD, EDX, SEM and BET. The obtained HAp granules were white, single phase of HAp, with specific surface area of 73 m2/g, size of granule about (2 × 10) mm. HAp granules were used for the removal of Zn2+ ions from aqueous solution. The effect of factors on the Zn2+ adsorption property was investigated. The adsorption efficiency and capacity obtained 77.15 % and 2.57 mg/g, respectively at suitable batch adsorption condition: HAp granule mass of 0.5 g/ 50mL solution, initial concentration of 20 mg/L Zn2+, contact time 40 minutes and pH0 5.7 at 30 oC. The adsorption efficiency reached about 99.55 % at suitable column adsorption condition: contact time of 3,5 min, flow rate of 14 mL/min, adsorption zone height of 4Ф (Ф = 2.5 cm), initial concentration of 20 mg/L Zn2+, HAp granule mass of 11.9 g/ 2L solution, pH0 5.7 at 30 oC.