ZIF ‐8‐Embedded Polystyrene Nanofibrous Composite Membrane for Water‐In‐Oil Emulsion Separation

ABSTRACT Efficient separation of emulsion mixtures is essential for eradicating oil contamination, emphasizing the need for superhydrophobic membranes. In this study, we report the fabrication of a superhydrophobic/superoleophilic (SH/SO) polystyrene (PS) nanofibrous membrane embedded with zeolitic imidazolate framework‐8 (ZIF‐8) nanoparticles for the efficient separation of water‐in‐oil emulsions and immiscible oil/water mixtures. The incorporation of ZIF‐8 imparts enhanced surface roughness, O/W separation efficiency, and excellent thermal and chemical stability to the membrane. The electrospun ZIF‐8/PS composite nanofibrous membrane demonstrates significant enhancements in permeate flux, water contact angle (WCA), absorption capacity, and separation efficiency compared to the pristine nanofibrous membrane. The composite nanofibrous membrane exhibits a WCA of approximately 155° ± 1.5°. The water‐in‐diesel emulsion achieves an oil permeate flux of 1886 ± 91 L/m 2 h, whereas the flux for immiscible diesel/water separation reaches 2936 ± 103 L/m 2 h. Furthermore, the ZIF‐8/PS composite nanofibrous membrane effectively separates oil from water/sunflower oil, water/bean oil, water/peanut oil, and water/diesel emulsions. The composite membrane achieves a separation efficiency of 99% ± 0.5% and exhibits excellent reusability and chemical stability. These attributes underscore the potential of the ZIF‐8/PS composite nanofibrous membrane for practical oil/water separation applications.