Ultrathin microporous membrane with high oil intrusion pressure for effective oil/water separation

Hydrophilically-modified mesh filter membranes have been widely researched for oil/water separation due to their high permeating flux and excellent separation efficiency. However, the low oil pressure resistance of mesh membrane is a major drawback limiting its practical oil/water separation applications. In this work, we report an ultrathin microporous membrane developed via the decoration of a stainless steel mesh filter with electrospun poly(acrylic acid) grafted poly(vinylidene fluoride) (PAA-g-PVDF) nanofibers. The network structure of the nanofiber layer reduces the pore size of the stainless steel mesh to improve its oil pressure resistance, and simultaneously maintains a high active separation area to preserve the highly permeable feature of the mesh filter membrane. Therefore, this composite membrane exhibits high permeating flux (up to 53574 L m−2 h−1 under gravity) and high oil intrusion pressure (>6000 Pa) at the same time. Satisfactory permeating flux and separation efficiency are achieved in various oil/water separation experiments and multiple operating cycles, which demonstrate the great potential of the membrane for practical oily wastewater treatment applications.