Thermodynamic Study of The Adsorption of Some Azo Dyes on Activated Carbon


This work is concerned with studying the adsorption of some azo dyes better on commercial activated carbon. The dyes were synthesized by considering the resorcinol as constant part in their structure which is reacted with a number of para substituted aniline via dizonium ions and used as adsorbate for achieving this study. These dyes were identified by a number of physical tests and the available spectroscopic methods. Three models of adsorption isotherms namely, Freundlich, Langmuir , and Tempken are applied to fit the experimented data of adsorption at equilibrium in the range of concentration (1*10-4- 5*10-4)M at various temperatures (292-328)K, and using (1gm/L) of the Adsorbent (Activated Carbon). The results showed that, the Freundlich isotherm is better fitted to the experimental data of the studied systems, although Langmuir isotherm exhibited good fit. This work included performing thermodynamic, depending on calculating the equilibrium constants by different methods, which represented by Freundlich constant Kf, Langmuir constant (KL) and finally is described by Tempkin constant (TK). The results showed good consistency among the four sets of functions in terms of their values and physical meaning. This consistency gave good indication for the accuracy of such kind of calculation.