Facile Fabrication and Application of Superhydrophilic Stainless Steel Hollow Fiber Microfiltration Membranes

Superhydrophilic stainless steel hollow fiber microfiltration membranes (SSHF-MFs) were developed through a facile dip-coating method, followed by sintering at a low temperature of 500 °C. A novel mediating additive was explored to mediate the coating suspensions. The additive, which could form hydrogen bonds with TiO2 agglomerations, facilitated the formation of a continuous TiO2 layer on the rough surface of stainless steel hollow fibers (SSHFs). The fabricated SSHF-MFs exhibited superhydrophilic and underwater superoleophobicity wettability, which enabled SSHF-MFs to be applied to antifouling fields. The fouling resistance of SSHF-MFs for oil/water emulsion, cake layer foulant (sodium alginate, SA), and adhesive foulant (bovine serum albumin, BSA) were investigated systematically. SSHF-MFs exhibited superior antifouling properties and high rejections of 99% and 90% for oil/water emulsion and SA foulant solution, respectively. For the adhesive BSA solution, SSHF-MFs still showed good antifouling property after washing with a dilute alkaline solution and superior separation performance (90%). Meanwhile, SSHF-MFs exhibited an excellent separation performance for polystyrene microspheres (100 nm) with a rejection of 100%. In conclusion, SSHF-MFs showed great potential, not only in traditional microfiltration fields, such as solid–liquid separation, but also in the antifouling field, such as oil/water separation. The facile fabrication conditions and superior wettability further improved the sustainability of SSHF-MFs in practical applications.