Potential application of dodecylamine modified sodium montmorillonite as an effective adsorbent for hexavalent chromium

Clay materials are well suited for heavy metal adsorption in view of their excellent surface area and cation exchange capacity. In this paper, we report the detailed study on the adsorption of hexavalent chromium using dodecylamine intercalated sodium montmorillonite as a potential adsorbent. The adsorption involves primarily the electrostatic interaction of hydrogentetraoxochromate(VI) anion with the protonated dodecylamine and the surface hydroxyl groups of the clay material. The pseudo second order kinetic model fits the experimental data and an adsorption capacity of 23.69 mg g(-1) was obtained from the Langmuir isotherm model. The exothermically favorable spontaneous adsorption process and the decrease in entropy explain the thermodynamics of the adsorption. The adsorbent could be regenerated using NaOH and column adsorption studies provide a sample break through volume of 300 mL on a laboratory scale. The adsorbent could be utilized for the successful removal of chromium from tannery wastewater. (C) 2012 Elsevier B.V. All rights reserved.