Preparation of <scp> SiO ₂ </scp> / <scp>TP</scp> ‐ <scp>MCE</scp> Membranes With Hydrophilicity for Oil–Water Emulsion Separation

ABSTRACT With the intensification of industrial activities, oil pollution in water bodies has become increasingly severe, necessitating the development of highly efficient and environmentally friendly oil–water separation technologies. This study employed a combined impregnation and vacuum filtration method to modify mixed cellulose ester (MCE) membranes with tea polyphenols (TP) and hydrophilic silica (SiO 2 ) nanoparticles, creating SiO 2 /TP‐MCE composite membranes exhibiting high hydrophilicity and submerged oleophobicity. Results indicate that TP modification significantly enhances membrane surface hydrophilicity, reducing the water contact angle to 62° after 24 h immersion and achieving a water flux of 31,217.1 L·m −2 ·h −1 , representing a 2.85‐fold increase over the original membrane. The incorporation of SiO 2 further endows the membrane surface with high hydrophilicity and underwater superhydrophobicity. The optimal composite membrane (M5) achieved a separation efficiency of 99.6% for diesel emulsion, demonstrating excellent anti‐fouling properties and cycling stability. Based on green and sustainable materials and processes, this composite membrane holds broad application prospects in industrial oily wastewater treatment and marine oil spill emergency response.