Title
Adsorption of Remazol Brilliant Violet onto chitosan 10B in aqueous solution: kinetics equilibrium and thermodynamics studies
Authors
SUBARNA KARMAKER AMLAN JYOTI NAG and TAPAN KUMAR SAHA

Received August 15, 2018
Published Volume 53 Issue 3-4 March-April
Keywords adsorption, kinetics, equilibrium, thermodynamics, chitosan, azo dyes

Abstract
The adsorption characteristics of Remazol Brilliant Violet (RBV) dye onto chitosan 10B were investigated in aqueous solutions as a function of solution pH, dye concentration, ionic strength and temperature, respectively. The adsorption kinetics data obtained from various batch experiments were analyzed by using pseudo-first- and pseudo-second-order, as well as Elovich and intraparticle diffusion kinetic models. The results exhibited that the sorption process obeys pseudo-second order kinetics, whereas intraparticle diffusion is the rate determining step. The equilibrium adsorption isotherm data are fitted better by the Langmuir model rather than by the Freundlich, Temkin and Dubinin Radushkevich models. Moreover, the mean adsorption energy (E) from the Dubinin-Radushkevich isotherm and the activation energy (Ea) from the Arrhenius equation indicate that the RBV adsorption onto chitosan 10B is a physisorption process. Thermodynamic parameters, such as the changes in free energy (∆G), enthalpy (∆H) and entropy (∆S), suggest that the RBV dye adsorption onto chitosan 10B in aqueous solution is spontaneous and endothermic in nature. Desorption tests were carried out in a NaOH solution (pH 12.5) and the chitosan flakes were found to be reusable.