In Situ Fabrication of Magnetic Iron Oxide over Nano-hydroxyapatite Gelatin Eco-polymeric Composite for Defluoridation Studies

This research work deals with the defluoridation studies of magnetic iron oxide (Fe3O4) fabricated nano-hydroxyapatite (n-HAp) gelatin (Gel) eco-polymeric composite. The developed hybrid Fe3O4@n-HApGel composite displays a high defluoridation capacity (DC) of 5009 mgF–·kg–1. Batch sorption experiments were performed to find the effect of various influencing parameters such as pH, contact time, competitor co-anions, initial fluoride concentration, and temperature. The structural, surface morphological changes, and elements present in the sorbent were studied using FTIR, XRD, and SEM with EDAX techniques. The equilibrium isotherm study was fitted with Langmuir isotherm model. The thermodynamic parameter values indicate the spontaneous and endothermic nature of fluoride sorption. The proposed mechanism indicates that the enhanced DC of magnetic composite is mainly due to electrostatic adsorption and complexation between fluoride ion and composite in addition to ion-exchange. The regeneration and reusability studies were performed for the effective utilization of the magnetic composite. The performance of Fe3O4@n-HApGel nanocomposite at field conditions was checked with the water sample collected from a nearby fluoride prevalent area.