Adsorção de íons de metálicos utilizando cortiça funcionalizada com ferro fluido em sistemas em lotes e coluna de leito fixo

Abstract

Water is a valuable resource that is valued by societies, and it is important to minimize or avoid its contamination. There are many techniques for treating water contaminated with heavy metals, such as adsorption, precipitation and ion exchange columns. Due to technical or economic limitations, new, cheaper technologies, such as adsorption, are being sought. In this sense, the use of efficient adsorbents is proposed, such as cork, which is considered to be a natural material with a combination of properties that make it suitable for use in multiple applications, both in industry and in construction, with an emphasis on wine bottling and insulation material. This work began with the reduction of cork to an effective diameter of 0.71 mm, with a uniformity coefficient of 1.5 indicating that all the particles are perfectly equal. The physical and chemical parameters of the cork functionalized with ferrous fluid (density, porosity and pH at the point of zero charge) which influence the adsorption process. It had a porosity of 12.4 and a density of 179.3 kg m-3 and a pH at the zero-load point of 4.3. The adsorbent was characterized using infrared (IR) analysis with bands at 475 and 466 cm-1 related to Fe-O vibrations, X-ray diffraction (XRD) with a peak around 20ο corresponding to the amorphous structure of cork and energy dispersive X-rays (EDX). The characterization results showed the presence of magnetite. Batch adsorption experiments were carried out, starting with solutions with concentrations of 2 mg L-1 for the Cu2+, Mn2+ and Cd2+ ions, stirring for 20 minutes at different pH values (2, 6 and 8). The effectiveness of the adsorbent was demonstrated for the three ions studied, with removal efficiencies of over 50%. The kinetic models for the adsorption of Cu2+, Cd2+ and Mn2+ on cork functionalized with ferrous fluid confirm the better applicability of the pseudo-second order equation, as shown by the coefficient of determination of 0.84, 0.97 and 0.85 respectively. The results for the Cu2+, Cd2+ and Mn2+ adsorption isotherms showed that the equilibrium data fitted the Langmuir model very well. In the batch system, a maximum adsorption capacity of 5.23 mg of copper per gram of adsorbent and an efficiency of 90% were obtained with a saturation time of 100 minutes, under the following conditions: initial concentration of 2 mg L-1, particle size of 0.841 mm, Cu+2 solution flow rate of 3.8 mL min-1, adsorbent mass of 50 mg.