title: Uptake of fluoride by nano-hydroxyapatite/chitosan, a bioinorganic composite.
abstract: A bioinorganic composite namely nano-hydroxyapatite/chitosan (n-HApC) composite which could be employed for technology development was prepared and studied for its defluoridation efficiency. It has been observed that there was a slight enhancement in the defluoridation capacity (DC) of n-HApC composite (1560mgF(-)/kg) than nano-hydroxyapatite (n-HAp) which has a DC of 1296mgF(-)/kg. The sorbents were characterized with XRD and TEM studies. The fluoride sorption was explained with Freundlich and Langmuir isotherms. Thermodynamic parameters such as DeltaG degrees , DeltaH degrees , DeltaS degrees and Ea were calculated in order to understand the nature of sorption. The sorption process was found to be controlled by pseudo-second-order and pore diffusion models. Field studies were carried out with the fluoride containing water sample collected from a fluoride-endemic area in order to test the suitability of the sorbents at field conditions.
authors.affiliation: Department of Science and Humanities, Karaikal Polytechnic College, Karaikal 609609, Puducherry, India. sairam_adithya@yahoo.com
authors.forename: C
authors.initials: C
authors.lastname: Sairam Sundaram
authors.forename: Natrayasamy
authors.initials: N
authors.lastname: Viswanathan
authors.forename: S
authors.initials: S
authors.lastname: Meenakshi
mesh_terms: D000327:Adsorption; D048271:Chitosan / Q000737:chemistry*; D004058:Diffusion; D017886:Durapatite / Q000737:chemistry*; D005459:Fluorides / Q000737:chemistry* / Q000302:isolation & purification; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D053761:Nanocomposites / Q000737:chemistry*; D013816:Thermodynamics; D013997:Time Factors
chemical_list: D048271:Chitosan; D017886:Durapatite; D005459:Fluorides