Aminated superhydrophilic/underwater superoleophobic collagen fiber membrane for efficient separation of anionic surfactant-stabilized oil-in-water emulsions

Separating anionic surfactant-stabilized oil-in-water emulsions remains a critical challenge due to the presence of surfactants. In this study, we developed a unique collagen fiber-based CFM-PEI-TiO2 with superhydrophilic and underwater superoleophobic properties, enabling efficient separation of various anionic surfactant-stabilized oilin-water microemulsions and nanoemulsions through charge demulsification effects. The membrane achieved high separation flux (1458.50 L & sdot;m- 2 & sdot;h- 1) and separation efficiency (99.94%) simultaneously. Importantly, the membrane exhibited remarkable mechanical durability, as it remained capable of separating diverse oil-in-water emulsions even after being subjected to abrasion with sandpaper for 500 cycles, highlighting its long-term durability and economic viability. The robust membrane also demonstrated excellent recyclability, with a separation efficiency of over 99% after twelve cycles and a flux of 1299.10 L & sdot;m- 2 & sdot;h- 1 after fifteen cycles. These properties can be attributed to the PEI-induced electrostatic interactions and the enhanced superhydrophilicsuperoleophobic interaction provided by TiO2 on the unique collagen fiber membrane. The outcomes emphasize the versatility and potential of our membrane in overcoming the challenges associated with emulsified oily wastewater.