Binding of Zn(II) ions to chitosan–PVA blend in aqueous environment: Adsorption kinetics and equilibrium studies



Zinc ion [Zn(II)] is the one of the most toxic and common among the heavy metal pollutants of industrial effluents. The present investigation has been aimed at describing the synthesis and characterization of biodegradable nanoparticle based on chitosan, then blending with biodegradable synthetic polymer (polyvinyl alcohol, PVA) and which was applied for the removal of Zn(II) ions from the aqueous system. The prepared nanoparticle and the chitosan blended polymers were characterized using transmission electron microscope (TEM), scanning electron microscope (SEM), and X-ray diffraction (XRD) analyses. The adsorption behaviour of chitosan blended polymer for Zn(II) ions has been studied as a function of solution pH, adsorbent dose, contact time, and adsorbate concentration in a batch system. The maximum adsorption was observed as 99.45% for an initial Zn(II) ions concentration of 10 mg/L for the solution pH of 5.0 and contact time of 30 min and at 5 g/L of adsorbent dose. The adsorption kinetics was investigated by fitting the experimental data to the pseudo-first order, pseudo-second order kinetic models, Weber and Morris intraparticle diffusion and Boyd kinetic models. Adsorption equilibrium data were analyzed by the Langmuir and Freundlich adsorption isotherm models and it was found that the Langmuir isotherm model fits best with the experimental data. The desorption of Zn(II) ions from the spent chitosan/PVA blend was carried out by HCl solution. The results of the present study showed the polymer blends may act as an effective adsorbent for the removal of Zn(II) ions from the aqueous solution. © 2014 American Institute of Chemical Engineers Environ Prog, 34: 15–22, 2015