Adsorption of malachite green onto chitosan from aqueous solution

The aim of this study to find economic and effective method for adsorbtion of malachite green (MG). In this study, the adsorption of malachite green MG on chitosan was studied under different conditions (pH, ionic strength, temperature). The results indicate that a pH value of 7.8 is optimum value for the adsorption of MG on chitosan. The adsorption kinetics was interpreted using pseudo-first-order kinetic model, pseudo-second-order kinetic model and intraparticle diffusion model. The pseudo-second-order model provides the best correlation with the experimental data of chitosan adsorption. The adsorption data could be fitted with Freundlich and Langmuir equation to find the characteristic parameters of each model. It was found that linear form of Langmuir isotherm seems to produce a better model than linear form of Freundlich equation. From the Langmuir and Freundlich equation, the adsorption capacity values raised as the solution temperature decreased. Determination of the thermodynamic parameters Hº, Sº and Gº showed that adsorption was spontaneous and endothermic in nature. It was also added that adsorption of MG by chitosan may involve chemical adsorption As a conclusion , chitosan can be used as adsorbent for the revoval of MG from aqueous solution.