One-step melt-blending method for synchronous realization of ionic liquid-intercalated montmorillonite and modified poly(vinylidene fluoride) membrane for efficient wastewater purification

The pollution of water resources is becoming increasingly severe, and the development of separation membranes with excellent purification performance is crucial for addressing this issue. Conventional membrane modification methods often suffer from multi-stepprocedures and the susceptibility of functional components to leaching. This study introduces a novel one-step melt-blending strategy that utilizes ionic liquids (ILs) as both grafting monomers and intercalation agents. This approach simultaneously achieves graft modification of poly(vinylidene fluoride) ( PVDF) chains and intercalation into Sodium-based montmorillonite (Na⁺MMT) interlayers. The proposed “grafting-intercalation co-construction” mechanism not only significantly streamlines the preparation process but, more importantly, fundamentally prevents IL leaching during membrane formation and operation. Furthermore, the intercalated structure creates additional selective transport pathways for water molecules. The PVDF-g-ILs/MMT composite membrane demonstrates hydrophilic and underwater superoleophobic characteristics, achieved the PWF of 310.8 L·m⁻²·h⁻¹ , represented the 330 % enhancement compared to pristine PVDF membranes, while maintained rejection rates exceeding 98 % for both dye molecules and oily wastewater. The membrane exhibits remarkable long-term stability, maintained flux recovery rates (FRR) of 92 % for dyes and 90 % for emulsions after 5 filtration cycles, significantly outperforming PVDF membranes. The study not only provides an efficient membrane for wastewater purification, but more importantly offers a highly promising paradigm for membrane material design. By integrating multiple functionalities through a one-step synergistic strategy, it provides new insights for addressing the challenges of complex industrial wastewater treatment.