Facile synthesis of hydroxyapatite/yeast biomass composites and their adsorption behaviors for lead (II).

For the first time, the hydroxyapatite (HAp)/yeast biomass composites were successfully synthesized through a facile alkaline ultrasound cavitation method, and used as a novel sorbent for removal of Pb(2+) from aqueous solution. The obtained HAp/yeast biomass composites were characterized by various techniques, including SEM, EDX, XRD, TGA, FTIR, XPS and fluorescence detection, respectively. It was found that the yeast cells were wrapped by the well-dispersed HAp, and more functional groups (such as carboxyl, hydroxyl and amino) on yeast surface were exposed. Also, varying factors that may affect the adsorption efficiency of HAp/yeast biomass composites, such as solution pH, reaction temperature and time, have been carefully investigated respectively. Remarkably, more than 99% of Pb(2+) can be removed by the HAp/yeast biomass composites. Evidence from FTIR and XPS analysis revealed that the higher removal efficiency should be ascribed to the synergetic effect of synthesized HAp and more functional groups exposed on yeast surface.