EFFECT OF ACTIVATED LOW COST CARBON ON ADSORPTION KINETICS AND THERMODYNAMICS OF CONGO RED DYE

摘要

Batch experiments were carried out for the sorption of Congo red onto acid activated carbon prepared. Langmuir and Freundlich isotherm equations evaluated the adsorption capacity and it was 11.31mg/l. The rate constant values confirm the irreversibility for the adsorption process. From the effect of temperature thermodynamic parameters like endothermic (△H°), spontaneity (△G°) as well as the disorderncss (△S°) on the surface of the carbon was evaluated. The dimensionless separation factor value (around 0-1)shows the ongoing adsorption is much more favourable. At pH 6 the carbon removed 80% of Congo red and this pH can be considered as optimum. Desorption study reveals that the spent carbon may be recycled for the adsorption. The mechanism of adsorption for that dye onto carbon was investigated by using the experimental results and confirmed by FT- IR, XRD and SEM images.