THE STUDIES OF ADSORPTION ISOTHERMS AND KINETICS OF CHROMIUM REMOVAL FROM TANNERY EFFLUENTS USING CROSS-LINKED CHITOSAN OBTAINED FROM SNAIL SHELL

Abstract
Chitosan is a natural polymer that has been employed in dye adsorption. In this work, adsorption and thermodynamic data for the interaction of Chromium in tannery effluent with chitosan in aqueous solutions were investigated. The equilibrium adsorption isotherms were determined, from 298 to 345 K. Adsorption data were adjusted to Langmuir, Freundlich, as well as Pseudo second order Kinetic model and van't Hoff model of analysis of adsorption parameters. The analysis showed that the Langmuir isotherm model was the most appropriate for fitting the experimental data, with a maximum monolayer adsorption of 33.3mg/kg at 298 K this value decreased with increase in temperature. The enthalpy of adsorption; ΔH, and the entropy; ΔS were – 13.54 kJ mol-1 and -0.1005kJ mol-1 K-1 respectively. The values demonstrated that the adsorption process was exothermic, favorable, and that randomness of the system decreased during the adsorption process. The Freundlich adsorption model, gave favorable constants; Kf and n consistent with good adsorption process. The pseudo-second reaction model gave straight line plot with rate constant of 1.1673x 10-3 kg mg-1 min-1 and the qe was 29.85 mg/kg, this showed that the adsorption of Chromium ion by the chitosan followed the pseudo-second order kinetic model
Description
A Thesis submitted to the School of Post Graduate Studies Ahmadu Bello Zaria In partial fulfillment of the Requirements for the award of Master Degree in Colour Chemistry and Technology Department of Textile Science and Technology, Faculty of Science, Ahmadu Bello University, Zaria, Nigeria MARCH 2013
Keywords
ADSORPTION,, ISOTHERMS,, KINETICS,, CHROMIUM,, TANNERY,, CROSS-LINKED,, CHITOSAN,, SNAIL SHELL
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