ABSTRACT:
This study is aimed to the synthesis of new azo dyes starting with 4-Aminoantipyrine. The thermodynamic behavior of the dyes adsorption on a new kind of activated carbon prepared from (Asphalt : Polymer) mixtures are studied. The research involved the selection of the optimum conditions for the adsorption process by studying the factors affecting it such as the effect of adsorbent dose, contact time, initial concentration and temperature, the work also included the fitting of two models of isotherm equations (Freundlich, Langmuir isotherms) on experimental data of adsorption models under consideration. This study was carried at different temperature and at range of concentrations. The constants of these isotherms were used to describe the nature of the studied systems and the type of interaction between dye and carbon surface. Depending on the results obtained from adsorption study at different temperature, the values of thermodynamic functions of adsorption were calculated at different concentration, using the equilibrium constant which obtained from the ratio between the concentration of the adsorbed and the free dye in solution. The above results showed that, the adsorption of these dyes are of physical nature and the experiential data were better obeyed Langmuir isotherm. The study also involved employing four kinetic models on the experimental data; pseudo first order, pseudo second order, Elovich and intraparticle diffusion equations. The results of this study showed that, the adsorption system under investigation obeyed the Pseudo second order model and the intraparticle diffusion is not the only mechanism controlling the adsorption systems under study.