Removal of Cd²⁺ by hydroxyapatite adsorption granule from aqueous solution

Abstract

Hydroxyapatite (HAp) adsorption granules with average size of 2x10 mm was fabricated from HAp powder and polyvinyl alcohol (PVA) additive by sintering for removing of Cd²⁺ ions from aqueous solution. The effect of some factors on the Cd²⁺ adsorption efficiency and capacity was investigated. The removal efficiency and capacity reached 86.5 % and 4.33 mg/g, respectively, at condition: HAp granule mass of 0.3 g, initial Cd²⁺ concentration of 30 mg/L, contact time of 40 minutes and pH₀ of 5.7 at 30°C. The experimental data was described by Langmuir and Freundlich isotherm models; pseudo-first order and pseudo-second order kinetic equations.