Desenvolvimento de um sistema de tratamento de efluentes por separação magnética

Abstract

In this study, a system was developed to capture magnetic particles synthesized by the Sol-Gel method. These particles were also used to remove boron in synthetic samples. The magnetic materials consist of: nickel ferrite composite (comp-Ni), cobalt ferrite composite (comp-Co), and pure cobalt ferrite (FCo). These materials were characterized by X-Ray Diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FTIR) techniques. In the comp-Co experimental planning, it was evaluated how the suspension concentration and the residence time in the reactor influence the efficiency of capture of adsorbent material (ECMA). For this, the suspension concentrations and residence time used are in the range of 1.3333-12.0000 g.L-1 and 0.5-1 min, respectively. Both factors are significant in the magnetic separation process. By keeping the residence time constant, there is a concentration at which the ECMA is maximum so that in higher concentrations the system tends to be more inefficient. For constant concentration, ECMA increases with residence time. ECMA for comp-Ni and FCo was determined for a concentration of 9.26 g.L-1 and residence time in the range of 0.5-1 min. The substitution of 75% FCo for MgO to form the comp-Co the ability of CSM to capture this material decreases. Comparing the ECMA of the comp-Co and the comp-Ni, there was little divergence between the results, a reduction of ECMA less than 5% for comp-Ni was observed. On the other hand, when it comes to removing boron, comp-Ni removed about 12% more than comp-Co. The adsorption experiment was carried out with synthetic effluent containing 6 ppm of boron which was kept in agitation (750 rpm) for 48 h with 9.26 g.L-1 of adsorbent material (comp-Co and comp Ni). After the adsorption process with comp-Ni, it was possible to reach a useful concentration for irrigation, below 2.5 ppm