Design of hydroxyapatite aerogel with excellent adsorption performance to uranium

Abstract Hydroxyapatite (HAP) was a highly efficient uranium adsorbent and its adsorption performances were depended on morphology and structure. In order to obtain HAP with better morphology and structure, HAP aerogels were prepared via freeze-drying-calcination method with konjac gum, xanthan gum and chitosan as template in this work. In contrast, HAP aerogel prepared with konjac gum as template (K-HAP) possessed better pore structure and particle distribution, providing more adsorptive sites for the removal of uranium from wastewater. The adsorption efficiency and capacity of uranium on K-HAP were 99.2% and 2070.3 mg g-1, respectively, which were much higher than many absorbents reported (pH = 4, m/V = 0.1 g L-1 and T = 298 K). The immobilization of uranium on HAP aerogel could be explained by the formation of Ca(UO2)2(PO4)2⋅3H2O. Due to the remarkable adsorption performance, K-HAP was supposed to be applied in the practical treatment of uranium-containing wastewater in the future.