Preparação de membranas zeolíticas (Y/gama-alumina) utilizando diferentes métodos e sua avaliação no processo de separação emulsão óleo/água.

Abstract

The zeolite membranes have attracted attention of researchers in separation processes and catalysts since they have high thermal and chemical stability, are highly selective because of the potential on the molecular sieve. The innovation of this study gives the synthesis of zeolite membrane Y/ɣ-alumina for oil/water separation. This study aimed to: prepare the zeolite Y via hydrothermal synthesis, ɣalumina by decomposition of aluminum sulfate and ethyl aluminum and zeolite membranes using three different methods: steam transportation and secondary growth: dip-coating and rubbing. The products obtained were characterized by XRD, nitrogen adsorption of Physics, SEM, DTA and TG, ED-XRF and Porosimetry Mercury. In addition to the synthesis and characterization in a second step the zeolite membranes were evaluated in the process of removing oil/water of a synthetic effluent using a column separation membrane. Assays were performed under the conditions of the initial oil concentration 500 mg.L-1, temperature of 25 °C and atmospheric pressure, allowing to observe the change in concentration of the permeate (mg.L-1) and the rejection coefficient ( R%). For synthesis of the precursors used were alumina aluminum sulfate and aluminum acetate using decomposition temperatures of 1000 °C and 850 °C respectively. Was selected alumina which had lower operating costs, so, ɣ-alumina originating from the thermal decomposition of aluminum sulfate. The zeolite Y and zeolite membranes Y/ɣ-alumina were prepared in hydrothermal conditions, with a temperature of 90 for 7 hours. Thermal changes were performed (500, 600, 700, 750, 800, 900, 950, 1000 and 1100 °C) per period of 1 hour and 2 hours in aluminum sulphate (after milling, shaping and compacting). Based on the XRD results it can be concluded that: (i) the starting materials (aluminum sulphate and aluminum acetate) to evolve heat, resulting in a finished product ɣ alumina; (ii) it can get the zeolite Y; It also noted the formation of ɣ-alumina ceramic brackets after sintering. Thermal study on ceramic support (DTSA) showed that the optimum temperature should be limited to values between 700-750 °C/1h. The greatest amount of crystallinity was observed for material treated at 700 °C/1h. The same was classified as a mesoporous materials can be used in ultrafiltration process (UF). The results of the characterization of the zeolite membranes showed that they were obtained with successful independent of the method used. From tests separation of the emulsion oil/water can be concluded that the insertion of zeolite (Y) to the ceramic support (ɣ-alumina) improved separation process of the oil/water emulsion. As a general conclusion, the obtained zeolite membranes used in membrane separation column are very promising in the separation process oil / water emulsion.