Advancing polybenzimidazole organic solvent nanofiltration membranes with oxygen-rich crosslinking for rapid polar solvent flux

Abstract

In this work, we engineered organic solvent nanofiltration (OSN) membranes using polybenzimidazole (PBI) and oxygen-rich crosslinkers to optimize performance in polar solvent environments. The robust bonding between PBI and acyl chloride groups in the crosslinkers ensured outstanding stability even in harsh organic solvents including dimethylforamide and tetrahydrofuran. Filtration testing with organic dyes revealed that our membranes possess a sharp molecular separation performance in organic solvents. In a comparative study with two different crosslinkers, the membrane with the higher oxygen-content agent exhibited an ethanol permeance of 30.85 L m- 2 h- 1 bar- 1, while the membrane with lower oxygen content showed 25.27 L m- 2 h- 1 bar- 1. This discrepancy can be attributed to increased interaction between the oxygen-rich membrane and polar solvents, a conclusion further validated by molecular dynamic simulations. Remarkably, the membrane developed, especially when crosslinked with high oxygen-content crosslinkers, demonstrated superior separation efficiency for ethanol compared to established benchmarks in the literature. Overall, this study underscores the promising application potential of our developed membrane for polar organic solvent filtration across various industrial settings.