Elimination of Chromium (VI) and Cadmium(II) from Aqueous Solutions by Adsorption onto Olive Stones

Karima Rouibah1, 2, Abdeslam-Hassen Meniai*, 1, Mohamed Tahar Rouibah2, Lazhar Deffous2, Mossaab Bencheikh Lehocine1
1 Laboratoire de l’Ingénierie des Procédés d’Environnement, Université Mentouri Constantine, Algeria
2 Département de Chimie Industrielle, Université de Jijel, Algeria

© 2009 Rouibah et al.

open-access license: This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 International Public License (CC-BY 4.0), a copy of which is available at: This license permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

* Address correspondence to this author at the Laboratoire de l’Ingénierie des Procédés d’Environnement, Université Mentouri Constantine, Algeria, Tel: +213 662 57 14 26; Fax: +213 31 81 88 80; E-mail:


The present study concerns the test of olive stones as an adsorbent for removing Cd(II) and Cr(VI) from aqueous solutions. The experimental elimination of the two cations was carried out batchwise and the influence of certain physico-chemical parameters such as the contact time, the pH of the solution, the temperature, the solid to liquid ratio, the agitation speed were also considered. The equilibrium adsorption capacity of the olive stones for the case of Cr(VI) followed the Langmuir model, whereas for the Cd(II) cations, the two models i.e. Langmuir and Freundlich were equally representative. The adsorption process was found to be of pseudo second order and the rate constants were determined for both cations. The Gibbs free energy sign was negative for the adsorption of both cations, indicating that the process was spontaneous. Finally the olive stones retained chromium more than cadmium, but at optimal conditions, high removal percentages were reached, for both cations.

Keywords: Olive stones, adsorption, retention, chromium, cadmium, isotherm.