Materials Research Bulletin, Vol.46, No.2, 205-209, 2011
Fluoride removal performance of glass derived hydroxyapatite
A novel sodium calcium borate glass derived hydroxyapatite (G-HAP) with different ranges of particle size was prepared by immersion sodium calcium borate glass in 0.1 M K(2)HPO(4) solution by the ratio of 50 g L(-1) for 7 days. The unique advantage of C-HAP for the adsorption of fluoride ions in solutions was studied. The effects of size and quantity of particles, pH value and adsorption time on adsorption performance were investigated. The maximum adsorption capacity was 17.34 mg g(-1) if 5 g L(-1) <100 mu m G-HAP was added to a solution with an initial pH value of 6.72 and the adsorption time was 12 h. The results showed that the micro-G-HAP could immobilize F(-) in solution more effectively than commercial nano-HAP, which makes potential application of the C-HAP in removing the fluoride ions from wastewater. The adsorption kinetics and isotherms for F- could be well fitted by a second order kinetic model and Freundlich isotherm model respectively, which could be used to describe the adsorption behavior. The mechanism of G-HAP in immobilizing F- from aqueous solutions was investigated by the X-ray diffraction (XRD), infrared spectra (IR) and scanning electron microscopy (SEM). (C) 2010 Elsevier Ltd. All rights reserved.