Solvent resistant nanofiltration membrane based on polybenzimidazole

Polybenzimidazole (PBI) membranes with different morphology were prepared via traditional phase inversion method and applied in solvent resistant nanofiltration (SRNF) application. The morphology of the membranes was tuned via changing polymer concentration and adding volatile solvent in cast solutions. The morphology of the membranes was studied in detail by scanning electronic microscopy (SEM). The membranes show less macrovoids sublayer and denser skin layer with increasing polymer concentration in cast solution. The evaporation of volatile solvent is beneficial to forming a thicker skin layer. In this paper, PBI based membranes were also applied in the filtration of organic solvents, where dyes with different charge and size were selected to study the role of charge in solvent filtrations. The membranes showed more than 95% retention on positive charged MB (MW = 160) in alcohol based medium, which is very promising for SRNF application.