Zeolite properties improvement by chitosan modification—Sorption studies

Abstract

Abstract In the paper the potential of chitosan modified zeolite (NaP1CS) as a cheap adsorbent for methylene blue (MB) removal from aqueous solutions was determined. Fourier transform infrared spectroscopy analyses, nitrogen adsorption/desorption isotherms and scanning electron microscope were applied to characterize the adsorbent. Batch adsorption studies were carried out to examine effects of various factors such as pH, contact time, initial MB and Cu(II) concentrations, temperature influence on the sorption process. The impact of different ways of zeolites modification with chitosan on sorption capacity and the comparison of adsorption of unmodified zeolite and fly ash are presented. The effect of different metal ions such as Cu(II), Zn(II), Mn(II), Fe(III) and also that of foreign ions on the MB sorption were also studied. The pseudo-first order, pseudo-second order and intraparticle diffusion models were fitted to the kinetic data. The best fit was achieved with both the pseudo-second order and intraparticle diffusion models. The experimental equilibrium data were evaluated by the Langmuir, Freundlich, Temkin and Dubinin-Radushkevich isotherm models. The calculated thermodynamic parameters indicated a spontaneous and endothermic sorption process. Desorption studies were carried out with different desorbing agents. HCl proved to be the most effective desorption agent for MB and Cu(II).