The purpose of this study is to characterize the clay of Toritama (Pernambuco, Brazil), in its form "in nature", and also after thermal activation at 500 °C, aiming its use in the removal of Cd2+. The clay "in nature" was characterized byg X-ray spectrometry by dispersive energy (EDX), X-ray diffraction (XRD), and surface area measurement by physical adsorption of nitrogen (BET). The thermally activated clay (100, 200, 300, 400 e 500 °C) was characterized by XRD. The thermally activated clay (500 °C) was characterized by EDX and surface area measurement (BET). The removal of Cd2+ by the thermally activated clay was carried out in a finite bath system. The thermal treatment of the clays slightly modified their area but did not change the pore diameters distribution. The experimental data for the finite bath system could be adjusted to both the studied adsorption isotherm models, Langmuir and Freundlich. However the Freundlich model was more satisfactory. The process of cadmium removal, in finite bath system, for thermally activated clay (500 °C) reaches the equilibrium after 120 min and presents about 86.8 % of cadmium removal.
thermally treatment; characterization; clays; heavy metal; adsorption
