Photocatalytic TiO2@CS-embedded cellulose nanofiber mixed matrix membrane

Photocatalytic mixed matrix membrane (MMM) was fabricated from a visible light active carbon sphere-titania core-shell (TiO2@CS) structure photocatalyst and the hydrophilic and super-robust cellulose nanofibers (CNFs, the kind of 20∼60 nm in diameter), and its photocatalysis, water permeability, and anti-fouling properties were examined in comparison with those from commercial UV-active P25 and visible light-active Pt/TiO2. It was found that photocatalysts can be effectively embedded in CNF-textured matrices by a simple filtration approach to render mild photocatalysis to the MMMs. While the powder-form TiO2@CS shows a smaller but somehow medium UV-active photocatalysis as compared to P25 and Pt/TiO2, its MMM performs better photocatalysis (both UV and visible light active) than those from the other two. This is attributed to light scattering by CNFs and the enhanced broad window visible light absorption of TiO2@CS, which make it possible to exert photocatalysis inside the deeper depth of the MMM. In addition, the photocatalytic MMM made from the larger sized and more dispersed TiO2@CS benefits from an expanded and looser composing structure which facilitates a better water permeability and achieves a meaningful improved anti-fouling effect.