DEFLUORIDATION, KINETICS AND EQUILIBRIUM STUDIES OF WATER BY MEANS OF ACTIVATED CARBON DERIVED FROM COLLARD GREEN LEAVES

Ability of Collard green leaves based thermally activated carbon to eliminate fluoride from aqueous solution has been studied. The batch adsorption studies were carried out at neutral pH as the functions of contact time, adsorbent dose, adsorbate concentration, temperature and effect of co-anions, which are commonly present in water. Rate of adsorption was rapid for the duration of initial 115 minutes and attained equilibrium. Adsorption isotherms have been figured by Langmuir and Freundlich isotherms. The data indicate that prepared adsorbent surface sites are heterogeneous in nature and it fits into a heterogeneous site binding model. Enthalpy change (ΔH°) and entropy change (ΔS°) for the adsorption reaction were calculated as +7.648 kJ/mol and +0.05 J/mol K correspondingly. The adsorption is endothermic in nature. 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 sorbent at field conditions and obtained good success rate.