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Size-dependent defluoridation properties of synthetic hydroxyapatite


Gao, S and Sun, R and Wei, Z and Zhao, H and Li, H and Hu, F, Size-dependent defluoridation properties of synthetic hydroxyapatite, Journal of Fluorine Chemistry, 130, (6) pp. 550-556. ISSN 0022-1139 (2009) [Refereed Article]

Copyright Statement

Copyright 2009 Elsevier B.V.

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DOI: doi:10.1016/j.jfluchem.2009.03.007


Batch adsorption experiments were conducted to investigate the removal of fluoride from aqueous solution by the addition of synthetic hydroxyapatites (HAps) with different particle sizes. Results showed that size-dependent defluoridation properties of HAps. Better performances were obtained with smaller particle sized HAps, which presented higher adsorption efficiency. Bulk HAp, the HAp sample with the largest particle size, presented the lowest percentage of fluoride removal. The isotherm studies showed that the Freundlich model was the best choice to describe the adsorption behaviors of nanosized HAps. However, the adsorption pattern of the bulk sample followed both Langmuir and Freundlich isotherms. All parameters that might influence the defluoridation process were assessed, which included the effect of adsorbent dose, initial fluoride concentration, contact time and the effect of temperature. The removal efficiency of fluoride increased with increasing adsorbent dose. Decrease of the initial fluoride concentration resulted in the increase of fluoride removal efficiency. The percentage of fluoride removal increased as the ambient pH decreased. Thermodynamic parameters suggested that the adsorption of fluoride onto HAp samples was physisorption and endothermic in nature. Moreover, adsorption kinetic study revealed that the adsorption process followed pseudo-second-order kinetics. This work indicated that synthetic hydroxyapatites, especially the smaller particle sized HAps, were efficient defluoridation materials.

Item Details

Item Type:Refereed Article
Keywords:hydroxyapatite, size-dependent, defluoridation, adsorption
Research Division:Chemical Sciences
Research Group:Analytical chemistry
Research Field:Separation science
Objective Division:Expanding Knowledge
Objective Group:Expanding knowledge
Objective Field:Expanding knowledge in the chemical sciences
UTAS Author:Wei, Z (Professor Zhenggui Wei)
ID Code:91143
Year Published:2009
Web of Science® Times Cited:118
Deposited By:Austn Centre for Research in Separation Science
Deposited On:2014-05-09
Last Modified:2014-06-12

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