ABSTRACT
In the present study, polysulfone membranes with addition of 3% by mass of natural montmorillonite clay, sodic and lithium, from the state of Paraiba, were developed by phase inversion method. The N-methyl-2-pyrrolidone (NMP) was used as a solvent in the proportion of 80% and 20% solid. The clays and membranes were also characterized by X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). In addition, the membranes were characterized by scanning electron microscope (SEM), porosity and vapor permeation of water in order to study their behavior in gas separation applications. The XRD of the clays showed peaks of crystallinity characteristic of montmorillonite. The XRD diffractograms of membranes showed that it has possibly occurred the formation of a structure intercalated/exfoliated due to the absence of peaks related clays. By FTIR of the clays were visualized the same bands characteristic of the montmorillonite, differentiating by the cations that were changed in the structure. The FTIR of the membranes presented bands characteristic of polysulfone, and for the hybrids these bands can also be of the clays because they present the same ranges of wave number. The SEM photomicrographs showed the formation of a dense layer on the filter skin and on the inferior surface was observed fingers structures that may have influenced the permeation. The porosity test indicated that the presence of clay in membranes reduced the amount of pores and the permeation test using water vapor showed that there was a decrease in the permeation by adding clay in comparison to pure polysulfone membrane. The membrane with additives of clay with lithium presented a 53% reduction of gas permeation, indicating better barrier properties.
Keywords:
membrane; polysulfone; clay; barrier property
