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The development of ceramic membranes with different geometries and compositions extends the possibilities of industrial applications, inducing advantages in terms of increased permeability, membrane area by volume module and chemical, thermal and mechanical resistance. The use of low-cost raw materials is a trend that has grown in scientific research. The aim of this work is to prepare membranes with hollow fiber geometry from alumina and residue of quartzite, by the technique of immersion precipitation in distilled water from a mixture of ceramic mass with a solution of polyethersulfone and, synthesized in temperatures of 1100 ºC to 1500 °C. The hollow fiber membranes were characterized by chemical analysis, X-ray diffraction, particle size distribution, scanning electron microscopy, apparent porosity, flexural strength and permeated water flow by the membranes. The results indicated that the sintering temperature has direct influence on the formation of the mullite phase, and the properties of apparent porosity and permeate flow. The higher the sintering temperature (1400-1500 ° C) increase the formation of the mullite phase, the lower the porosity, as well as the lower the permeate water flow in the membranes. However, there was increase in flexural strength in the hollow fiber membranes with high temperature.
The nanocomposites have an extensive use in the current process of membrane preparation, taking into account their unique features as membranes. Thus, the study of nanocomposite processing to obtain membranes is highly important. In this work, Brazilian clay was used (Brasgel PA) for the preparation of polyamide/clay nanocomposite. The nanocomposites were produced in a high rotation homogenizer and in a twin screw extruder. From the nanocomposites and pure polymers processed in the two equipments, membranes were prepared by the immersion-precipitation method, using formic acid as solvent. By X-ray diffraction (XRD), the formation of exfoliated and/or partially exfoliated structures with changes in the crystalline phases of the polyamide was observed. From scanning electron microscopy images, it was observed that the processing clearly influenced the membrane morphology.
Polyethersulfone (PES) hollow fiber membranes were produced, containing 3% of two types of clay (Brasgel PA-MMT and Cloisite NA-CLNa), in order to modify the characteristics of the polyethersulfone membrane. By means of the X-ray diffraction, it was possible to observe an exfoliated and/or partially exfoliated structure in the membranes containing clay. From the analysis of contact angle, it was possible to notice an increase in the hydrophilicity of the membrane with the introduction of the clay. Through scanning electron microscopy (SEM), the morphology of the porous support of the membrane was modified with addition of clay, favoring greater uniformity of the pores and fingers. In the flow measurements with distilled water, the membranes with clay obtained the highest flows, being the greater flow with the Cloisite Na clay (~22 L/h.m 2) and was in agreement with the contact angle results. In the analysis of permeation with the oily emulsion, the membrane with Brasgel PA clay in its structure presented the greatest flow (~16 L/h.m 2) and the membrane with Cloisite Na presented the greatest yield (78.28%). Therefore, the clay acted by modifying both the morphology and the hydrophilicity of the polyethersulfone membrane, improving flow and yield.
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