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Enhanced adsorption of fluoride from aqueous solution onto nanosized hydroxyapatite by low-molecular-weight organic acids

Citation

Wang, Y and Chen, N and Wei, W and Cui, J and Wei, Z, Enhanced adsorption of fluoride from aqueous solution onto nanosized hydroxyapatite by low-molecular-weight organic acids, Desalination, 276, (1-3) pp. 161-168. ISSN 0011-9164 (2011) [Refereed Article]

Copyright Statement

copyright 2011 Elsevier B.V.

DOI: doi:10.1016/j.desal.2011.03.033

Abstract

The effects of low molecular weight organic acids (LMWOAs) on the defluoridation capacity of nanosized hydrpxyapatite (nHAP) from aqueous solution were investigated. Defluoridation capacity of nHAP was enhanced in the presence of LMWOAs. The nHAP adsorbed LMWOAs on its surface, and the LMWOAs on nHAP were considered to be the newly formed active sites for fluoride adsorption. At low pH, the adsorbed LMWOAs were protonated, positively charged, and thus could attract fluoride anions by electrostatic attraction. Meanwhile, the protonated LMWOAs could also form hydrogen bonding with fluoride. At high pH, the LMWOAs on nHAP were deprotonated and existed as anions. These organic acid anions on nHAP could be exchanged with fluoride. It was evident that with increasing aqueous LMWOAs concentrations, the LMWOAs adsorbed onto nHAP increased, and subsequently the defluoridation capacity of the adsorbent increased. Results also indicated that the defluoridation capacity increased with increasing the contact time, while decreased with the increase of the adsorbent dose or solution pH. In the presence/absence of LMWOAs, the adsorption isotherms were well fitted by the Freundlich model (R2 > 0.98), and the sorption kinetics were well described by the pseudo-second-order model. Moreover, thermodynamic parameters indicated that the adsorption was spontaneous and endothermic.

Item Details

Item Type:Refereed Article
Keywords:defluoridation capacity, low-molecular-weight organic acids, nanosized hydroxyapatite, 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
Author:Wei, Z (Professor Zhenggui Wei)
ID Code:91136
Year Published:2011
Web of Science® Times Cited:38
Deposited By:Austn Centre for Research in Separation Science
Deposited On:2014-05-09
Last Modified:2014-06-12
Downloads:0

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