Adsorption Isotherm Studies of Chromium (VI) from Aqueous Solutions Using Jordanian Pottery Materials

Removal of Cr(VI) from aqueous solution using low-cost adsorbents such as Jordanian Pottery materials under different experimental conditions was investigated in this study. The effects of initial metal concentration, agitation time, pH on the removal of Cr(VI) were studied. In order to investigate the sorption isotherm, four equilibrium models, Langmuir, Freundlich, Dubinin and Radushkevich, and Tempkin isotherm models, were analyzed. The effect of solution pH on the adsorption onto pottery was studied in the pH range 1-5. Adsorption of Cr(VI) is highly pHdependent and the results indicate that the optimum pH for the removal was found to be 3 for all types of pottery materials. The thermodynamic parameters (free energy change G, enthalpy change S and entropy change H) for the adsorption have been evaluated and therefore, it was showed the spontaneous and endothermic process of the adsorption of Cr(VI) on the pottery materials.