REMOVAL OF LEAD FROM TEXTILE WASTE WATER USING CHITOSAN PRODUCED FROM SNAIL SHELL.

Abstract: The sorption process of lead (II) ions from textile effluent was investigated using chitosan obtained from a snail shell (SSC). The effects of various experimental parameters on Pb (II) ions adsorption were studied, and optimal conditions were determined. The equilibrium data were analyzed with Langmuir, Freundlich, Temkin, Elovich, Florry Huggins, Jovanovic, Harkin Jura, and Dubinin–Radushkevich (DRK) adsorption models. The high correlation factor of Langmuir isotherm indicates the monolayer coverage of the adsorbent. Freundlich isotherm fitted the adsorption data excellently. The adsorption intensity (n) is 1.68. This means the suitability of the adsorption process. The adsorption process is beneficial when the adsorption intensity is between 1 and 10. Adsorption kinetics data for sorption of Pb2+ ion unto chitosan were analyzed using the pseudo-first order, pseudo-second order, and intraparticle diffusion models. The results indicated that the pseudo-second-order model best described the adsorption kinetic data. For the thermodynamic studies, the enthalpy change, ΔH°, and the entropy change, ΔS°, for the adsorption processes are -18.10 kJ/mol and -0.0652 KJ/mol K respectively. The free energy, ΔG° for the process are 2186.39 J/mol, 3071.761 J/mol, 3689.615J/mol, and 4153.032 J/mol at 303K, 313K, and 323K respectively. The thermodynamic parameters showed that the adsorption of lead into SSC was exothermic and non-spontaneous.