Membranas cerâmicas a partir de alumina e resíduo de quartzito.

Abstract

Ceramic membranes expand the possibilities of industrial applications, due to advantages in terms of permeability and resistance (chemical, thermal and mechanical). Low-cost raw materials and/or from recycling is a trend of economy and sustainability that has grown in the midst of scientific research. The aim of this work is to obtain membranes in different tubular formats and of hollow fiber from alumina and residue of quartzite. The research was divided in two steps: the first step developed tubular membranes (TM) before and after chemical attack (TMA); The second step were hollow fiber membranes (HFM) before and after chemical attack (HFMA). The chemical attack was intended to increase the porosity of the membranes. The tubular membranes were obtained by extrusion, and the hollow fibers were developed by the technique of phase inversion allied with sintering. The membranes were sintered in

temperatures of 1100, 1200, 1300, 1400 and 1500°C. And were characterized by X- ray diffraction (XRD), scanning electron microscopy (SEM), apparent porosity, mercury

intrusion porosimetry, permeated water flow analysis, and capacity of separation of chemical species (water-oil and Indigo Blue). The results indicate that the raw materials of alumina and residue of quartzite presented potential to form membranes both in tubular format and in hollow fiber. The sintering temperature had direct influence on proprieties the membranes as well as on the formation of the mullite phase. Comparing the hollow fiber membranes (HFM) with the tubular ones (TM), it can be noticed that the hollow fiber ones presented greater efficiency on porosity and flow measurements. Between these, the membrane that most stood out in selectivity was HFM - 1400 °C (0.5 Bar), reaching performance of 97.68% on the oil-water separation. The chemical attack contributed on modifying the membranes morphology. The increase of the concentration and the time of exposure to the acid promoted more pores, contributing to the increase of the apparent porosity and the permeated water flow both on the TM and on the HFM, which on the other hand decreased the flexure strength. In terms of selectivity, the most efficient membrane was the HFM 2% HFMA -1500 -7.5 min with performance of 99.88% on the oil-water separation, and 99.73% on the Indigo Blue.