ADSORPTION OF METHYL VIOLET ONTO MULTI-WALLED CARBON NANOTUBES: EQUILIBRIUM, KINETICS AND MODELING

Adsorption equilibrium and kinetics of methyl violet onto multi-walled carbon nano-tubes were studied in a batch system. Experiments were carried out as function of contact time, initial concentration, and temperature. Langmuir, Freundlich and Temkin isotherm models were applied to experimental equilibrium data of methyl violet adsorption depending on temperature. The data fitted well with the Langmuir isotherm. The maximum adsorption capacities were found to be 32.87, 46.10, 58.01, and 71.76 mg/g at 0, 25, 45, and 60 degrees C. The adsorption data were modeled using pseudo-first and second-order models. It was shown that the second-order kinetic equation could best describe the sorption kinetics. Thermodynamic parameters Delta H-0, Delta S-0 and Delta G(9) have been calculated. Results suggested that methyl violet adsorption on multi-walled carbon nano-tubes is a spontaneous and endothermic process.