Avaliação da influência da incorporação de óxido de grafeno e de óxido de grafeno reduzido no desempenho de membranas de polisulfona para permeação de gases

Abstract

Membrane separation processes are an interesting alternative when compared to conventional separation processes due to their greater selectivity and possibility of implementation on an industrial scale. Polymeric membranes added with graphene-based materials are being studied due to the improvement of their mechanical, chemical and thermal properties. In this study, polysulfone membranes (PSU) were prepared by the phase inversion, loaded with graphene oxide (PSU/OG) and reduced graphene oxide (PSU/OGR) at a concentration of 0.5 % m/m, in order to compare their characteristics and physicochemical properties. Membrane morphology was evaluated by scanning electron microscopy, thermal stability by thermogravimetric analysis, functional groups and material structure by Fourier-transform infrared spectroscopy and the mechanical properties by pressure test and gases permeation test, using synthetic air. The agglomeration of graphene oxide and its reduced form was verified, a factor that may have interfered in the performance of the membranes. There was no increase in thermal stability in the membranes with the addition of graphene derivatives and neither the occurrence of new bands observed in the infrared spectrum, meaning that there were only physical interactions between the materials. Furthermore, all membranes resisted the maximum pressure of the gas permeation system, and it was not possible to identify whether the addition of graphene-based materials interfered positively on the mechanical strength. PSU/OG membranes performed better in permeability during the gas permeation test than PSU and PSU/OGR membranes, possibly due to the functional groups present in graphene oxide. This study reinforces the importance of producing membranes, especially with additives, in order to evaluate their effect on their properties. [resumo fornecido pelo autor]