Thermodynamic and Kinetic Study of Adsorption of Azo Dyes Derived for 4-amino Anti pyrene by Activated Carbon

A commercial activated carbon was used for the study of adsorption of two diazo dyes from aqueous solution employing batch method. These dyes were synthesized in our laboratory from the reaction of 4amino-antipyrene 4-AAP and β-Naphthol with p-amino phenol and p-amino benzaldehyde via diazonium ions. The effect of pH, temperature, and contact time on dye removal was investigated. The apparent thermodynamic parameters were estimated and the obtained results concluded that, the dyes adsorbed onto activated carbon are driven by entropy effect, exothermic and spontaneous processes. The kinetic study of adsorption of the considered dyes was conducted by applying four models the pseudo-first order, pseudosecond order ,Elovich and intra particules diffusion kinetic models. The results showed that, the second order equation fit better the experimental data. The intra particule diffusion model indicates that, there are more than mechanism controlling the adsorption process.