The influence of nano-sized TiO2 fillers on the morphologies and properties of PSF UF membrane

Polysulfone (PSF)/TiO2 organic–inorganic composite UF membranes were successfully prepared by phase-inversion method with Nano-sized TiO2 particles dispersed uniformly in 18 wt.% PSF casting solution. The influence of addition nano-sized TiO2 particles on the morphologies and the properties of such PSF/TiO2 membranes were investigated through the methods of SEM, XRD, DSC, contact angle goniometer, viscosity measurements, UF experiments and mechanical strength tests. The results showed that the rheological properties of casting solution were changed from Newtonian viscous behavior to non-Newtonian viscous behavior with an increasing viscosity of casting solution and the PSF/TiO2 composite membranes exhibited differences in morphologies, porosities and properties due to nano-sized TiO2 addition. At 2 wt.% TiO2 content, the composite membranes held excellent water permeability, hydrophilicity, mechanical strength and good anti-fouling ability with almost unchanged retentions. The DSC and XRD analysis indicated that there were interactions between TiO2 nanoparticles and polymers. However higher TiO2 content (than 2 wt.%) caused a serious nanoparticle aggregation to result in the performances of PSF/TiO2 membranes decline. The prepared membranes were also exhibited excellent ability to treat emulsified oil wastewater.