In situ symbiosed graphdiyne-based mixed matrix membranes for efficient ethanol recovery

Abstract

Mixed matrix membranes, which combine the advantages of polymer and inorganic membranes, have attracted significant attention in ethanol-selective pervaporation, but interfacial compatibility and scale-up fabrication remain critical challenges. Here, we propose an innovative “in situ symbiosis” synthesis strategy to directly assemble tris(4-ethynylphenyl) amine-graphdiyne (TPNGDY) in the polymer solution. The wrapping of PDMS chains promotes uniform dispersion of TPNGDY, while the rigid framework of TPNGDY restricts the movement of PDMS chains and mitigates excessive aggregation. This synergistic design not only enhances interfacial compatibility but also optimizes molecular diffusion transport channels, leading to a significant improvement in mass transfer efficiency. The resulting TPNGDY/PDMS MMMs exhibit excellent performance in pervaporation. When separating 5.0 wt% ethanol-water solution at 60 °C, the membranes exhibit an ultra-high flux of 7.42 kg m⁻² h⁻¹ and a separation factor of 10.79, corresponding to an 9.76 % increase in flux and a 127.16 % enhancement in selectivity compared to pristine PDMS membranes. Notably, defect-free industrial-scale membranes (1 m × 1 m) were successfully fabricated using a roll-coating approach, which overcomes the limitations of laboratory-scale fabrication. This work provides a practical and feasible solution to addressing filler-polymer interfacial compatibility and large-scale membrane fabrication.