Kinetics and equilibrium study of chromium adsorption on zeoliteNaX|
Pandey, P. K.; Sharma, S. K. & Sambi, S. S.
This study aims to report Batch adsorption study of hexavalent chromium, Cr (VI) on zeoliteNaX.
Kinetics of Cr (VI) adsorption and adsorption isotherms were determined by varying operating parameters such
as pH, initial concentration, temperature and contact time. ZeoliteNaX was found to remove Cr (VI) in acidic
solutions down to ppm level at pH of about 4. Removal rate of Cr (VI) was found to decrease as pH rises above
4.0. Langmuir, Freundlich, Temkin and Redlich-Peterson models were applied to adsorption equilibrium data to
find the best amongst these models. Langmuir model with R2 = 0.9711 best fits the adsorption data. The kinetics
of adsorption was found to follow the first order reversible reaction. The separation parameter, RL values of less
than 1.0 i.e., 0.7369, 0.5834 and 0.4828 corresponding to initial concentrations of 10, 20 and 30 mg/L, respectively
indicated that adsorption of Cr (VI) on zeoliteNaX is favoured. The estimated values of thermodynamic parameters
such as heat of adsorption and standard gibbs free energy confirmed the exothermic nature of adsorption of Cr (VI)
Diffusion; First order reversible reaction; Isotherm; Mass transfer; Regeneration; Thermodynamics