Abstract
Toxic metals cannot be biodegraded or destroyed, which leads to the need of their removal from industrial wastewaters. Therefore, so that you can design and optimize removal equipment (ion exchange/ adsorption column) is essential to characterize the adsorbent and to know the dynamics of adsorbate components in the experimental system. In this work, the bentonite clay called Fluidgel, from the northeast region of Brazil, calcined at 750 °C, was used as adsorbent for copper removal. The characterization methods used were Thermogravimetry (TG), X-ray Diffraction (XRD), N2 adsorption (BET), and Scanning Electron Microscopy (SEM). The removal of copper from aqueous solution was carried out in a fixed bed, built in glass with 15 cm high and 1.5 cm in internal diameter. Several dynamic experiments were performed to evaluate the effect of flow in adsorption efficiency. The experiments were accomplished at room temperature, the adsorbent particle diameter was of 0.855 mm and the flow rate varied from 2 to 4 mL/min. The feed concentration of copper was about 1.57 mmol/L. The bentonite clay used presented a chemical composition according to the most clays of this group. The presence of water in the interlamellarspaces of the clay was confirmed by thermogravimetric analysis, where the TG curve indicated a weight loss of 11.5 %. The Fluidgel clay calcined at 750 °C showed a surface area of 11 m2/g, whereas its commercial form presented 58 m2/g. The breakthrough curves obtained at different flow rates showed different behaviors, indicating the effect of diffusional resistances. The flow rate of 2 mL/min was chosen as operating condition, since higher values of metal removal and lower mass transfer zone (MTZ) were obtained.
