Facile fabrication of robust and tight PIMs-based TFC hollow fiber membranes with a semi-interpenetrating polymer network via liquid phase cross-linking for organic solvent nanofiltration

Abstract

Resource recovery and reuse are essential for sustainable development, particularly for high-value resources such as homogeneous (photo)catalysts, active pharmaceutical ingredients, and high-value natural compounds, which can offer economic benefits. Recently, organic solvent nanofiltration (OSN) for resource recovery has gained significant attention owing to its advantages including low energy consumption and seamless integration with other processes. Polymers of intrinsic microporosity (PIMs) have great potential as membrane materials for OSN, owing to their excellent pore properties and solution processability. However, swelling and dissolution of PIMs in organic solvents can impede the filtration performance of PIMs-based OSN membranes. In this study, we fabricated thin-film composite hollow fiber membranes for OSN based on PIMs with improved organic solvent stability using a semi-interpenetrating polymer network (semi-IPN) formed by cross-linking Matrimid with 1,6-hexanediamine within the PIMs through the liquid phase cross-linking method. Semi-IPNs mitigate swelling and tighten the pores of PIMs-based membranes, enabling excellent filtration and molecular separation performance. Furthermore, the fabricated PIMs with a semi-IPN membrane exhibited excellent rejection performance (>96 %) for homogeneous photocatalysts, allowing successful concentration and recovery via OSN. Therefore, PIMs-based membranes with a semi-IPN hold great promise as OSN membranes for the recovery of valuable resources.