title: Enhanced defluoridation and facile separation of magnetic nano-hydroxyapatite/alginate composite.
abstract: In this research study, a new magnetic biosorbent was developed by the fabrication of magnetic Fe3O4 particles on nano-hydroxyapatite(n-HAp)/alginate (Alg) composite (Fe3O4@n-HApAlg composite) for defluoridation in batch mode. The synthesized Fe3O4@n-HApAlg biocomposite possess an enhanced defluoridation capacity (DC) of 4050 mgF(-)/kg when compare to n-HApAlg composite, Fe3O4@n-HAp composite, n-HAp and Fe3O4 which possesses the DCs of 3870, 2469, 1296 and 1050 mgF(-)/kg respectively. The structural changes of the sorbent, before and after fluoride sorption were studied using FTIR, XRD and SEM with EDAX techniques. There are various physico-chemical parameters such as contact time, pH, co-existing anions, initial fluoride concentration and temperature were optimized for maximum fluoride removal. The equilibrium data was well modeled by Freundlich, Langmuir, Dubinin-Radushkevich (D-R) and Temkin isotherms. The present system follows Dubinin-Radushkevich isotherm model. The thermodynamic parameters reveals that the feasibility, spontaneity and endothermic nature of fluoride sorption. The performance and efficiency of the adsorbent material was examined with water samples collected from fluoride endemic areas namely Reddiyarchatram and Ammapatti in Dindigul District of Tamil Nadu using standard protocols.
authors.affiliation: Department of Chemistry, Anna University, University College of Engineering - Dindigul, Reddiyarchatram, Dindigul-624622, Tamil Nadu, India.
authors.forename: Kalimuthu
authors.initials: K
authors.lastname: Pandi
authors.affiliation: Department of Chemistry, Anna University, University College of Engineering - Dindigul, Reddiyarchatram, Dindigul-624622, Tamil Nadu, India. Electronic address: drnviswanathan@gmail.com.
authors.forename: Natrayasamy
authors.initials: N
authors.lastname: Viswanathan
mesh_terms: D000327:Adsorption; D000464:Alginates / Q000737:chemistry*; D005591:Chemical Fractionation / Q000379:methods*; D017886:Durapatite / Q000737:chemistry*; D005459:Fluorides / Q000737:chemistry*; D020723:Glucuronic Acid / Q000737:chemistry; D006603:Hexuronic Acids / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D058185:Magnetite Nanoparticles / Q000737:chemistry*; D053761:Nanocomposites / Q000737:chemistry*; D013816:Thermodynamics; D014867:Water / Q000737:chemistry
chemical_list: D000464:Alginates; D006603:Hexuronic Acids; D058185:Magnetite Nanoparticles; D014867:Water; D020723:Glucuronic Acid; D017886:Durapatite; D005459:Fluorides
keywords: Alginate; Biocomposite; Fluoride removal; Magnetic; Nano-hydroxyapatite