A comparative study of the defluoridation efficiency of synthetic dicalcium phosphate dihydrate (DCPD) and lacunar hydroxyapatite (L-HAp): An application of synthetic solution and Koundoumawa field water
Open Access
- 8 February 2015
- journal article
- Published by Academic Journals in African Journal of Environmental Science and Technology
- Vol. 9 (2), 111-125
- https://doi.org/10.5897/ajest2014.1843
Abstract
This paper deals with the comparison of defluoridation efficiency of two defluoridation agents by the use of dicalcium phosphate dihydrate (DCPD) and lacunar hydroxyapatite (L-Hap) as a fluoride sorbents. The DCPD and L-HAp are characterized by using XRD and FTIR techniques. Defluoridation of synthetic solution of sodium fluoride (NaF) and natural waters of Koudoumawa are studied. The fluoride removal capacity is as follows: DCPD: (26.37 mg.g-1; 0.0174 g, 9.81 mg.g-1; 0.1012 g) and L-Hap: (18.96 mg.g-1; 0.0174 g, 8.00 mg.g-1; 0.1012 g). The optimum 0.0623 g of DCPD/100 mL dosage of synthetic solution could bring down the level of fluoride within the tolerance limit, [F-] = 0.38 mg/l (WHO guideline value = 0.8 mg/l), the pH rise is 5.10 and the defluoridation time is 72 h. For L-Hap, it is 0.1012 g of L-Hap/100 mL, [F-] = 1.98 mg/l in the same conditions. For Koundoumawa natural waters, 0.0527 g of L-Hap/100 mL of solution could bring down the level of fluoride, [F-] = 0.84 mg/l. New mechanisms of fluoride removal by DCPD and L-HAp are proposed from which it is established that this material removes fluoride by ion-exchange, adsorption process, dissolution, precipitation and co-precipitation. Key words: Defluoridation, dicalcium phosphate dihydrate (DCPD), lacunar hydroxyapatite (L-Hap), adsorption, ion-exchange, dissolution-precipitation.Keywords
This publication has 38 references indexed in Scilit:
- Fluoride removal from water by adsorption—A reviewChemical Engineering Journal, 2011
- Magnesium incorporated bentonite clay for defluoridation of drinking waterJournal of Hazardous Materials, 2010
- Sorption behavior of fluoride ions from aqueous solutions by hydroxyapatiteJournal of Hazardous Materials, 2010
- Arsenic(V) removal from aqueous solutions using an anion exchanger derived from coconut coir pith and its recoveryChemosphere, 2007
- Retention of fluoride ions from aqueous solution using porous hydroxyapatite: Structure and conduction propertiesJournal of Hazardous Materials, 2004
- Adsorption kinetics of fluoride on low cost materialsWater Research, 2003
- WATER DEFLUORIDATION BY MEXICAN HEULANDITE–CLINOPTILOLITESeparation Science and Technology, 2002
- Adsorption of organic matter contained in industrial H3PO4 onto bentonite: batch-contact time and kinetic studyApplied Clay Science, 1993
- Dependence of in vitro Demineralization of Apatite and Remineralization of Dental Enamel on Fluoride ConcentrationJournal of Dental Research, 1990
- Application of Phase Rule to the Chemical Behavior of Monocalcium Phosphate Monohydrate in SoilsSoil Science Society of America Journal, 1959