Improve MOF-801 dispersibility in PVA membranes by a pre-crosslinking strategy for enhanced pervaporation performance

Abstract

Interfacial defect caused by the poor dispersibility of filler particles has been a major obstacle in the application of mixed matrix membranes (MMMs). Improving the fillers dispersibility is an effective approach to improve the separation performance. In this work, for the purpose of preparing defect-free MMMs, a pre-crosslinking strategy was proposed to covalently connect the fillers to the polymer. Such covalently connection realized by the reaction between the additional carboxyl group of the MOF-801 and the hydroxyl group of Polyvinyl alcohol (PVA). The newly reacted ester group, confirmed by Fourier Transform Infrared (FTIR), was identified as a bridge between MOF-801 and PVA. This bridge provides a strong bond between the two and avoids agglomeration between the MOF particles. The uniform distribution of Zr elements observed in the Energy Dispersive Spectrometer (EDS) mapping further confirms that the MOF-801 particles are well dispersed in the MMMs. The prepared membranes exhibited a superior water flux of 3354 g m⁻² h⁻¹ for 90 wt % ethanol/water separation at 343 K and excellent stability in 92 h experiment. This study provides an inspiration for mitigating excessive particle agglomeration in MMMs.