Superhydrophilic ZIF-8@PMIA Nanofibrous Membrane With Demulsification Property for Efficient Separation of Oil-in-Water Emulsions

Nanofibrous membranes have great potential for treating oily wastewater. However, the random stacking of nanofibers during the electrospinning process resulted in a broad pore size distribution and reduced separation efficiency. Moreover, for oil-in-water emulsions stabilized by ionic surfactants, the small oil droplets deform under the applied pressure and are squeezed into the membrane pores, leading to a decrease in flux and fouling. In this work, we developed superhydrophilic nanofibrous membranes with demulsification properties via electrospinning and a solvothermal seed-induced method. Notably, the incorporation of ZIF-8 nanoparticles offers multiple advantages, such as reducing membrane pore size, increasing the surface roughness, and enhancing membrane surface charge. These features synergistically improve both separation selectivity and demulsification properties. As a result, the membrane exhibits outstanding separation performance, achieving a separation efficiency of 96.37% for diesel-in-water emulsions and a high permeation flux of 4100 L m −2 h −1 for dichloromethane-in-water systems. This work provides an effective strategy for developing high-performance membranes for oil-in-water emulsions separation applications.