Microfluidic-engineered ZIF-8/MXene-based nanofiber membrane towards high-efficiency oil-water separation

The rapid industrialization has generated substantial amounts of oily wastewater, posing direct risks to human health, and ecosystems. Environmental-friendly and high-efficiency purification technology is highly desirable. Herein, we designed dual-functional polyvinylidene fluoride/polyacrylonitrile/ZIF-8-MXene (PVDF/PAN/ZIF-8-MXene) nanofiber membrane towards high-efficiency oil-water separation. Specially, ZIF-8 is continuously fabricated via microfluidics, where the channel diameter and solution flow rate could be precisely controlled to optimize the synthesis of ZIF-8 nanocrystals, overcoming drawbacks of long reaction times and broad size distribution in traditional methods. By continuously microfluidic electrospinning and spraying, PVDF/PAN/ZIF-8-MXene nanofiber membrane was fabricated, which exhibit dual functionality (hydrophilic oil-blocking and adsorption capture). The hydrophilic MXene layer forms a dense hydrated barrier, which significantly enhances water flux and mitigates membrane fouling. While ZIF-8 could capture tiny oil droplets, thereby efficiently improving oil-water separation efficiency. As expected, the composite membrane demonstrates excellent separation flux (6783∼9634 L m −2  h −1 ), superior separation efficiency (>99.5%) and outstanding recyclability in diverse oil-in-water emulsions. This work provides an efficient membrane for oil-water system purification, which gives a new insight into design of high-performance separation materials.