Multifunctional membranes embedded with core-shell Janus copper ferrite/titania nanoparticles for water purification and oil filtration

Industrial effluents are often polluted with more than one contaminant. This study presents the design of copper ferrite/titania core-shell nanoparticles (NPs) as a multifunctional platform for water remediation, demonstrating strong performance in the photocatalytic degradation of azo dyes as well as efficient oil-water separation. CuFe₂O₄ NPs were coated with a mesoporous TiO₂ shell to reduce e⁻/h⁺ recombination and enhance photocatalytic degradation of Congo red dye under sunlight. The resulting CuFe 2 O 4 /TiO 2 NPs had a size of 39.93 nm, a shell thickness of 5.2 nm, and a surface area of 30.016 m²/g. Surface treatment with ammonium fluoride introduced fluorine groups on the TiO 2 shell (Janus NPs), confirmed by an XPS signal at 686.1 eV, tailoring the surface for oil-water separation. These Janus NPs were embedded in a cellulose acetate/polyvinyl pyrrolidone (CA/PVP) membrane to create a dual-function material for dye degradation and oil separation. The F-CuFe 2 O 4 /TiO 2 /CA/PVP membrane exhibited an oil contact angle of 11° in air and 132° underwater, making it oleophilic and underwater oleophobic—ideal for diesel separation and membrane reuse. The membrane achieved 97.17 % Congo red degradation, 83 % diesel removal, and a 96.4 % flux recovery ratio. Compared to CA/PVP, Janus F-CuFe 2 O 4 /TiO 2 /CA/PVP membranes, offered improved thermal/mechanical stability, hydrophilicity, and a uniform pore size distribution with an average of 114.5 nm, resulting in superior separation efficiency.