Polyvinylidene fluoride (PVDF) membranes have been widely applied in the separation of various organic matters owing to their excellent properties. However, they possess low wettability and undergo fouling because of the hydrophobic nature of PVDF. In this study, poly (2‐hydroxyethyl methacrylate) (PHEMA) and poly (sulfobetaine methacrylate) (PSBMA) were co‐introduced to modify the highly hydrophobic PVDF membrane surface via UV photo‐irradiation. Facile UV photo‐grafting was performed by irradiating the pristine PVDF membrane immersed in a PHEMA/PSBMA mixture solution with UV light for 5 min. The performance of the as‐prepared PHEMA/PSBMA‐grafted membrane was compared with that of membranes modified with solely PHEMA or PSBMA. The hydroxyl and zwitterionic groups of the grafted membranes enhanced wettability and increased flux. A tightly bound water layer was formed because of the enhanced wettability, significantly suppressing protein adsorption. The initial flux of bovine serum albumin (BSA) solution through the PHEMA/PSBMA‐grafted membrane was 2861 LMH, which was 3.1 times higher than that obtained by the pristine PVDF membrane. Furthermore, the flux decline of the modified membrane caused by BSA fouling was 49% lower than that of the pristine PVDF membrane. Finally, the PHEMA/PSBMA‐grafted PVDF membrane showed antifouling properties after three BSA filtration cycles.

Fabrication of highly efficient oil/water separation membranes is attractive and challenging work for the actual application of the membranes in the treatment of oily wastewater and cleaning up oil spills/oil leakage accidents. In this study, hydrophilic poly(ethylene-co-polyvinyl alcohol) (EVOH) nanofiber membranes were made using an electrospinning technique for oil/water separation. The as-prepared EVOH electrospun nanofiber membranes (ENMs) exhibited a super-hydrophilic property (water contact angle 33.74°) without further treatment. As prepared, ENMs can provide continuous separation of surfactant-free and surfactant-stabilized water-in-oil emulsions with high efficiency (i.e., flux 8200 L m⁻² h⁻¹ (LMH), separation efficiency: >99.9%). In addition, their high stability (i.e., reusable, mechanically robust) would broaden the conditions under which they can be employed in the real field oil/water separation applications. Various characterization techniques (including morphology investigation, pore size, porosity, mechanical properties, and performance test) for gravity-driven oil/water separation were employed to evaluate the newly prepared EVOH ENMs.

In research on membranes, the addition of co-solvents to the polymer dope solution is a common method for tuning the morphology and separation performance. For organic solvent nanofiltration (OSN) applications, we synthesized polybenzimidazole (PBI) membranes with high separation properties and stability by adding acetonitrile (MeCN) to the dope solution, followed by crosslinking with dibromo-p-xylene. Accordingly, changes in the membrane structure and separation properties were investigated when MeCN was added. PBI/MeCN membranes with a dense and thick active layer and narrow finger-like macrovoids exhibited superior rejection properties in the ethanol solution compared with the pristine PBI membrane. After crosslinking, they displayed superior rejection properties (96.56% rejection of 366-g/mol polypropylene glycol). In addition, the membranes demonstrated stable permeances for various organic solvents, including acetone, methanol, ethanol, toluene, and isopropyl alcohol. Furthermore, to evaluate the feasibility of the modified PBI OSN membranes, ecamsule, a chemical product in the fine chemical industry, was recovered. Correspondingly, the efficient recovery of ecamsule from a toluene/methanol solution using the OSN process with PBI/MeCN membranes demonstrated their applicability in many fine chemical industries.