Interfacial assembly of flexible super-hydrophilic boehmite nanofiber membranes for efficient oil-water emulsion separation

One of the main challenges of inorganic membranes is their high cost and susceptibility to surface contamination, which hinders their practical application in oil-containing wastewater treatment. To address these limitations, flexible boehmite membranes were fabricated through the interfacial assembly (IA) of boehmite nanofibers and trimesoyl chloride (TMC), avoiding the traditional sintering process used for preparation of ceramic membranes. This fabrication method effectively preserves the hydroxyl groups on the membrane surface, thus presenting superior hydrophilicity. Consequently, the resulting membrane exhibits exceptional anti-fouling property, as evidenced by a flux recovery ratio as high as 96 % after 10 test cycles. Moreover, the non-rigid interconnections between nanofibers and their staggered stacking configuration endow the membrane with exceptional flexibility. This flexibility allows the membrane to withstand repeated bending of at least 50 times at a curvature of 100 m⁻¹ while still maintaining its separation efficiency. Overall, the findings highlight the potential of these flexible and contamination-resistant boehmite membranes for improved oil–water separation processes.