Membranas anisotrópicas de alumina sintetizada pelo método Pechini para aplicações em processos de separação.

Abstract

The anisotropic ceramic membranes obtained from synthetic powders are expanding their industrial applications, mainly because the advantages that present in terms of permeability and resistance (chemical, thermal and mechanical). The aim of this work is to obtain anisotropic membranes with the filtering layer of alumina synthesized by Pechini method for applications in separation processes. Membranes were prepared in the form of discs and later with tubular geometry with the best parameters evaluated on disk geometry. The support has been prepared with a ceramic mass consisted by a commercial alumina and bentonite. The intermediate layer was obtained with kaolinite clay and the filtering layer with synthesized alumina. The ceramic masses used for obtaining the membranes were characterized by chemical and thermal analysis, X-ray diffraction, particle size distribution and scanning electron microscopy (SEM). Alumina was synthesized by Pechini method in ratios of 2:1, 3:1 and 4:1 of citric acid:metallic cation. It were calcined at different temperatures and characterized by thermal analysis, X-ray diffraction, particle size distribution, and textural analysis by BET. Each layer that composed the membrane was characterized by SEM and optical microscopy, by intrusion mercury porosimetry and flow analysis with desalinated water. The intermediate and filter layer were obtained through the deposition of dispersions by dip -coating. The results showed membranes made with success, free from defects, with permeability of 317.53 L/h m 2 Bar. The membranes were efficient for the application in the treatment of oily water, reducing the concentration of 70 mg/L of oil in water at 100%; for application in separation of indigo blue the membrane reached 100% of rejectio n of solid particles of a solution with concentration of 0.25 g/L of indigo blue; water treatment using the raw sewage of a river the membrane reduced color, turbidity, ions present, ammonia, silica and iron and for application in separation of casein has been reached 97.4% of rejection in a solution with concentration 3.08 mg/mL.