GROUNDNUT SHELL: EFFECTIVE ADSORBENT FOR DEFLUORIDATION FROM AQUEOUS SOLUTION

Water defluoridation experiments were carried out on solid waste i.e Groundnut Shell (GS). The 10 ppm fluoride concentration solution and 4.5gm of GS were employed in experiments to determine defluoridation capacities, effects of pH and effects of temperature, effect of initial concentration, and effect of contact time on defluoridation. The highest defluoridation capacity of 92.8% was obtained with the dose of 4.5g/L. The adsorption follows a Pseudo second order kinetics, Elovich equation, Modified Freundlich equation. Equilibrium study is done and it follows Langmuir, Freundlich, and Temkin isotherm. The value of thermodynamic parameter ΔH indicated an exothermic adsorption process and the negative value of ΔG show the feasibility and spontaneity of material-anion interaction.