Adsorption studies on the removal of cationic dye from shrimp shell using chitin

Recent developments have given positive indications that biomaterials, in their nature or modified states are effective, environmentally friendly adsorbents of pollutants. This study investigates the chitin obtained from shrimp shell as an adsorbent for Crystal violet dye removal. Effect of various physico-chemical parameters such as contact time, initial dye concentration (250- 75 mg/L), pH (2-10) and temperature (293-333K) were investigated. Experimental data were analyzed by using Langmuir, Freundlich, Temkin and Dubinin – Radushkevich adsorption models. Equilibrium data were fitted well with the Langmuir model with maximum monolayer adsorption capacity of 37.02 mg/g. The kinetics of Crystal violet adsorption followed the pseudo-second order rate expression which suggests that intraparticle diffusion plays a significant role in the adsorption mechanism. Thermodynamic parameters, such as changes in Gibbs free energy ( G°), enthalpy ( H°) and entropy ( S°) were calculated to appreciate the nature of adsorption process. The surface morphology of chitin obtained from shrimp shell was studied using FTIR, SEM, and TG - DTG. The results of this work indicate that the chitin extracted from natural materials constitutes a promising and efficient low cost adsorbent for the removal of dyes from aqueous effluents.