Pearl-necklace-structured hollow MOF filled in membrane for molecular separation

Membrane technology is important for saving energy in the semiconductor industry through purifying isopropanol (IPA). The strategic incorporation of efficient molecular transport pathways into mixed matrix membranes (MMMs), known for their exceptional molecular selectivity and minimal diffusion resistance, presents challenges but holds promising potential for enhancing the progress of high-performance membrane production. This study proposes a novel surface coating-assisted etching strategy to synthesize a highly continuous metal-organic framework with a hydrophilic surface and distinct hollow structure (HZIF-8@PPy). When integrated into the polyvinyl alcohol (PVA) matrix, HZIF-8@PPy demonstrates exceptional compatibility at the interface and significantly enhances the membrane's capacity for selective water molecule transport. The pervaporation dehydration efficiency from an IPA aqueous solution shows significant enhancement, with selectivity and permeability reaching 5.9 and 3.7 times higher than those of the pristine PVA membrane, respectively. The effectiveness of HZIF-8@PPy's structure and its separation mechanism was validated by resolving the five types of molecular channels in MMMs during permselective pervaporation. This research holds significant implications for the purification of organic compounds and also presents new opportunities for developing robust and high-performance MMMs with effective fillers, thereby contributing to advancements in membrane technology.