Journal of Chemical Technology and Biotechnology, Vol.92, No.8, 1868-1875, 2017
Macroporous hydroxyapatite ceramic beads for fluoride removal fromdrinking water
BACKGROUND: This study evaluates the capacity of hydroxyapatite ceramics to remove fluoride from drinking water. Porous hydroxyapatite ceramic beads approximately 5mmin diameterwere fabricated using soluble potato starch aswell as insoluble rice starch, wheat starch, corn starch, and cellulose as pore-forming agents. RESULTS: Calcination of hydroxyapatite particles, followed by mixing with starches and water, compaction, and sintering at 1200 degrees C resulted in the formation of macroporous ceramic beads with maximum fluoride adsorption capacities ranging from 7 to 12mgg(-1), depending on the relative proportions of different pore-forming agents. Increasing the insoluble starch content from 0 to 25% by volume in ceramics with 50% by volume hydroxyapatite led to amarked improvement in fluoride adsorption by creating interconnected macropores, as evidenced by scanning electron microscopy (SEM). Calcination of hydroxyapatite powder at or above 400 degrees C before ceramic preparation was required to obtain a ceramic material with sufficient structural integrity to withstand operation and handling after sintering. CONCLUSION: This study evaluates the potential of using porous hydroxyapatite ceramics to remove fluoride from drinking water. An increase in fluoride adsorption capacity was consistent with the observation of macropores in SEM images as well as an increase in open porosity and specific surface area (SSA) measurements as the insoluble starch contentwas increased from 0 to 25%. (C) 2016 Society of Chemical Industry