EQUILIBRIUM AND KINETICS STUDY OF NITRATE REMOVAL FROM WATER BY PUROLITE A520-E RESIN

Abstract

Equilibrium and kinetics of nitrate removal from aqueous solutions of pH = 6.8 were investigated using the strong base anion exchange resin (Purolite A-520E) in the batch method.The experimental equilibrium data were analyzed by means of the Langmuir, Freundlich and Dubinin-Radushkevich sorption isotherm models.The Langmuir model describes sorption isotherm of nitrates with high correlation coefficients and better than Dubinin-Radushkevich and Freundlich models.The effect of temperature on the nitrates ion exchange process onto resin was also investigated, and various thermodynamic parameters, such as ΔG, ΔH and ΔS have been calculated.The thermodynamic parameters indicate the spontaneous and endothermic nature of the ion exchange process.The experimental curves q -t have bee confronted with three kinetic models, and the corresponding kinetic constants have been identified.The best fit of experimental sorption data was obtained by means of the pseudo-second order and intra-particle models.