Investigation of kinetics of adsorption of acidic blue 206 dye on multi-wall carbon nano tube using linear and nonlinear regression and activation energy determination

In this research, kinetics of remove of acidic blue 206, an acidic dye, from aqueous solution by multi wall carbon nanotube at optimized pH of 6.5 and 298K has been investigated. Six kinetics models contain pseudo first order, pseudo second order, intra-particle, elovich, bangham and modified freundlich model used. Kinetic data were fitted by these six models using linear and nonlinear regression. The results showed that pseudo second order model was best fitted in both linear and nonlinear regression methods. The rate determining step was the surface adsorption. The calculated qe at pseudo first order and pseudo second order models, (73mg/g and 75mg/g, respectively) are near the experimental value (99 mg/g). The order of compatibility of data with other models at nonlinear regression are pseudo first order> bangham> modified freundlich> elovich> intra-particle models. For leaner regression the order of compatibility of data are > bangham> elovich> modified freundlich> pseudo first order models. The calculated Arrhenius activation energy was -61.63kJ/mol. The negative activation energy, Ea, means that there is no barrier energy on surface adsorption and the adsorption is exothermic.