Solvent-resistant crosslinked polybenzimidazole membrane for use in enhanced molecular separation

Abstract

In molecular separation using membranes, enhanced parameters, such as an increased flux and selectivity, are required for efficiency. Additionally, in molecular separation using solvents, solvent resistance is critical in preventing solvent-induced damage. However, most membranes lack resistances to specific harsh solvents, and simultaneously enhancing solvent flux and selectivity performance, which exhibit a trade-off relationship, is challenging. In this study, a high-performance solvent-resistant polybenzimidazole (PBI) membrane is fabricated via chemical crosslinking with divinyl sulfone (DVS). The membrane consists of porous finger-like support and dense skin layers, and the uniform DVS crosslinking of the PBI membrane is confirmed via chemical analysis. The DVS-crosslinked PBI membrane exhibits a superior solvent stability and separation performance, with an ethanol permeance and molecular weight cut-off of 5.88 L m−2 h−1 bar−1 and 483 g mol−1, respectively. These values represent an enhanced permeance and rejection performance compared to those of the pristine membrane. The DVS-crosslinked PBI membrane also displays a long-term stability in mepenzolate bromide separation over 72 h.