Graphene oxide and reduced graphene oxide as additives in polysulfone hybrid membranes for gas permeation

Abstract

Hybrid polymeric membranes with the addition of graphene and derivatives are currently being developed and studied due to the unique properties of this material, whose addition in membranes is related to the enhancement of physical and mechanical properties and separation performance. In this study, polysulfone (PSU) membranes containing graphene oxide (PSU/GO) and reduced graphene oxide (PSU/RGO) were developed at a concentration of 0.5 wt.%, and their morphology, physical-chemical and thermal properties, and separation performance were evaluated. Membrane morphology was evaluated by SEM, thermal stability by TGA/DTG, functional groups and material structure by FTIR, mechanical properties by pressure test, and gas permeation using synthetic air. Agglomeration of GO and RGO was verified, a factor that may have interfered with the performance of the membranes. There was no change in the thermal stability of the membranes with the presence of GO/RGO, nor the occurrence of new bands observed in FTIR spectra, indicating that the interactions between PSU and GO/RGO were physical. All membranes resisted the maximum system pressure (6 bar), and it was not possible to identify whether the addition of graphene-derived materials had a positive effect on the mechanical strength. PSU/GO membranes had a better performance regarding synthetic air permeability in the gas permeation test than PSU and PSU/RGO membranes, possibly due to the functional groups present in GO, which facilitated the mass transfer within the polymer structure.