Abstract

Batch experiments are carried out for the sorption of Congo red, Malachite green and Rhodamine B dyes onto acid activated carbon. The operating variables studied are initial dye concentration, pH, temperature and contact time. The equilibrium data are fitted to the Langmuir and Freundlich isotherm equations. From these the adsorption efficiency, adsorption energy, adsorption capacity, intensity of adsorption and dimensionless separation factor are calculated. The rate constant value for the adsorption process is calculated. The temperature thermodynamic parameters like ∆G°, ∆H°, and ∆S° are calculated from the effect of temperature. The mechanism of dye adsorption for that dye onto carbon is investigated by using the experimental results. 

Key words: Pandanus carbon, Congo red, Malachite green, Rhodamine B dyes, Adsorption isotherms-Langmuir and Freundlich isotherms, Adsorption energy, Adsorption efficiency, Kinetic studies, Thermodynamic parameters, pH effect, Effect of other ions, Regeneration pattern.