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Journal of Colloid and Interface Science 217, 137–141 (1999)

Adsorption by activated red mud (ARM) is investigated as a possible alternative to the conventional methods of Cr(VI) removal from aqueous synthetic solutions and industrial effluents. Adsorption characteristics suggest the heterogenous nature of the adsorbent surface sites with respect to the energy of adsorption. Various factors such as pH, contact time, Cr(VI) concentration, amount of adsorbent, and temperature are taken into account, and promising results are obtained. | Journal of Colloid and Interface Science 217 137-141 1999 Article ID jcis.1999.6288 available online at http www.idealibrary.com on IDEM Adsorption of Hexavalent Chromium from Aqueous Solution by Using Activated Red Mud Jyotsnamayee Pradhan Surendra Nath Das and Ravindra Singh Thakur1 Regional Research Laboratory CSIR Bhubaneswar 751013 India Received January 7 1999 accepted April 14 1999 Adsorption by activated red mud ARM is investigated as a possible alternative to the conventional methods of Cr VI removal from aqueous synthetic solutions and industrial effluents. Adsorption characteristics suggest the heterogenous nature of the adsorbent surface sites with respect to the energy of adsorption. Various factors such as pH contact time Cr VI concentration amount of adsorbent and temperature are taken into account and promising results are obtained. The applicability of the Langmuir as well as Freundlich adsorption isotherms for the present system is tested. The loading factor i.e. milligrams of Cr VI adsorbed per gram of ARM increased with initial Cr VI concentration whereas a negative trend was observed with increasing temperature. The influence of the addition of anions on the adsorption of Cr VI depends on the relative affinity of the anions for the surface and the relative concentrations of the anions. 1999 Academic Press Key Words activated red mud adsorption hexavalent chromium removal. INTRODUCTION Rapid industrialization and usage of heavy metals in industrial processes have resulted in an unprecedented increase in the heavy metal flux into groundwater anid uic mttrad fffluenss. Like many heavy metals chromium in traces is necessary for life processes. However with higher concentration of this element in environment and the consequent increase in human intake chromium concentrations have reached toxic levels and manifested in a variety of ailments such as dermatitis congestion of respiratory tracts and perforation of the nasal septum. It is also a proven .