Superhydrophilic/underwater superoleophobic oil-in-water emulsion separation membrane modified by the co-deposition of polydopamine and chitosan-tripolyphosphate nanoparticles

Environmentally friendly separation materials are essential for separating emulsified oil-water mixtures. The nylon membrane has been facilely converted into highly hydrophilic and underwater superoleophobic via a simple one-step co-deposition of polydopamine and chitosan-tripolyphosphate (CS-TPP) nanoparticles, wherein the CS-TPP particles were prepared by the ion gel method. The modified membrane exhibited excellent antifouling performance with the underwater oil contact Angle (UOCA) at 179.6 degrees. The prepared environmental CS-TPP@PDA@nylon membrane was characterized by SEM, EDS, FTIR, and XPS. The membrane could separate various oil-in-water emulsions in a wide range of average particle sizes (50.9-1832.0 nm). In addition, the CS-TPP@PDA@nylon membrane demonstrated high permeation flux (221.0-1770.5 L m(-2) h(-1)) and good regeneration ability. The flux could still maintain more than 89% even after fifteen cycles. The degradable modification materials and simple preparation process would highlight the potential of modified membranes in large-scale production and green oily wastewater treatment.

Automated summary

Environmentally friendly membranes with high hydrophilicity and underwater superoleophobicity were prepared by co-depositing polydopamine and chitosan-tripolyphosphate nanoparticles onto a nylon membrane. The modified membrane exhibited excellent antifouling performance and could effectively separate oil-in-water emulsions of different particle sizes.