Some elements are considered toxic even in low concentrations, causing various public health problems. Cadmium is widely used in industrial activities and can cause contamination of soil and water. The red mud was studied for use as adsorbent in the removal of elements, composed of wastewater and/or contaminated soil. However, there are several compounds and treatments that have not yet been tested. In this study, the potential of Cd (II) adsorption for natural red mud (LV) and red mud activated by thermal treatment at 400°C (LVT) and chemical treatment with 0.05 mol L-1 HCl (LVQ1) and with Ca(NO3)2 0.1 mol L-1 (LVQ2) was evaluated. The LV and LVT presented higher percentage of Cd (II) adsorption in aqueous solution. The Freundlich isotherm was more appropriate to describe the phenomenon of Cd (II) removal, the thermally activated red mud had the highest adsorption capacity, 1.04 mmol g-1 or 107.52 mg g-1. These results indicate that LVT has potential for use in applications that treat effluents and / or contaminated soil from industrial activity.
