Abstract

BATCH ADSORPTION OF FLUORIDE IONS ONTO ACTIVATED CARBON DERIVED FROM CURLY KALE LEAVES

Veerati Radhika* and Halavath Ramesh

ABSTRACT

Adsorption of fluoride was done from its aqueous solution by using activated carbon. The ability of Curly Kale leaves based thermally activated carbon to eliminate fluoride from aqueous solution has been investigated. 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. The rate of adsorption was rapid during initial 110 minutes and attained equilibrium. Adsorption isotherms have been modeled by Langmuir, Freundlich isotherms. The data indicate that prepared adsorbent surface sites are heterogeneous in nature and that fits into a heterogeneous site binding model. The enthalpy change (ΔH°) and entropy change (ΔS°) for the adsorption reaction are calculated as +8.648 kJ/mol and +0.04 J/mol K respectively. 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.

Keywords: Fluoride, Curly Kale leaves, adsorption, isotherms, kinetic models.