Abstract:

Membrane separation has emerged as a critical technology for treating oily wastewater due to its high efficiency, low energy consumption, and elimination of chemical additives. Polyethersulfone (PES) membranes are widely applied in wastewater treatment owing to their excellent thermal stability and mechanical strength. However, it is still a difficult problem to prepare PES membranes with high porosity sponge pore structure and stable super-hydrophilicity to achieve high-flux and anti-pollution separation of oily wastewater. Herein, we report the vapor-induced phase separation (VIPS) method for the fabrication of PES membranes with sponge-like pores and stable super-hydrophilicity, using PES as the matrix, polyvinylpyrrolidone (PVP) as a hydrophilic additive, and polyethylene glycol (PEG) as a pore-forming agent. At the same time, the PVP free radical cross-linking reaction in the membrane induced by Na₂S₂O₈ inhibited the dissolution and loss of PVP, so that the PES membrane maintained a long-term stable super-hydrophilic property and anti-oil pollution performance. The cross-linking of PVP effectively restrains the leaching of PVP during long-term use of the membranes. The PES membranes demonstrate an outstanding oil-in-water emulsion separation efficiency exceeding 99.8%, with a high water flux of 3900 L·m^-2·h^-1·bar^-1, and exhibits excellent cycle performance, with a flux attenuation rate as low as 5.4%, and a flux recovery rate of more than 96.3% after water washing.

Key words: membrane, fabrication, fouling, oil-water separation, super-hydrophilicity

摘要：

膜分离技术因高效率、低能耗、无须化学添加剂等优势已成为处理含油污水的重要手段。聚醚砜(PES)膜由于出色的热稳定性和机械强度被广泛应用于水处理，但制备具有高孔隙率海绵孔结构和稳定超亲水性的PES膜，实现含油污水高通量、抗污染分离仍是一个难题。在此，通过水蒸气诱导相分离(VIPS)方法，以PES为成膜材料、聚乙烯吡咯烷酮(PVP)为亲水添加剂、聚乙二醇(PEG)为制孔剂制备了海绵孔结构的超亲水PES膜。同时通过Na₂S₂O₈引发膜内PVP自由基交联反应抑制PVP溶出流失，使PES膜保持长时间稳定的超亲水性质和抗油污染性能。此PES膜分离油/水乳液时分离效率高于99.8%，水通量达到3900 L·m^-2·h^-1·bar^-1，并展现出优异的循环性能，通量衰减率低至5.4%，水冲洗后通量恢复率高于96.3%。

关键词: 膜, 制备, 污染, 油/水分离, 超亲水