Kinetic, equilibrium and thermodynamic studies for the adsorption of methyl orange using new anion exchange membrane (BII)

摘要

The adsorption of methyl orange (MO) from aqueous solution by anion exchange membrane BII was investigated at room temperature using batch technique. The anion exchange membrane was characterized by fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM) and X-ray diffraction (XRD) techniques. The effect of various physico-chemical parameters such as contact time, membrane dosage, initial dye concentration, temperature and ionic strength on the removal of dye was investigated. Various kinetic models such as Lagergren's pseudo-first-order, -pseudo-second-order, liquid film diffusion, Elovich, modified Freundlich and Bingham were applied to the adsorption data and it was observed that the adsorption of MO follow the pseudo second order kinetic model. Linear forms of adsorption isotherm models such as Langmuir, Freundlich, Tempkin and Dubinin-Radushkevich (D-R) were used to reveal experimental data and the results indicate that the adsorption of MO on anion exchange membrane BII fitted well to the Langmuir isotherm model. Thermodynamic parameters such as change in Gibbs free energy (Delta G), Change in enthalpy (Delta H) and Change in entropy (Delta S) were also determined. The negative values of Delta G and Delta H showed that the adsorption of MO on anion exchange membrane was spontaneous and exothermic process in nature.