Supercritical Phase Inversion to Produce Photocatalytic Active PVDF-coHFP_TiO 2 Composites for the Degradation of Sudan Blue II Dye.

TiO 2 -loaded poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-coHFP) membranes were produced by supercritical CO 2 -assisted phase inversion. Three different TiO 2 loadings were tested: 10, 20, and 30 wt% with respect to the polymer. Increasing the TiO 2 amount from 10 wt% to 20 wt% in the starting solution, the transition from leafy-like to leafy-cellular morphology was observed in the section of the membrane. When 30 wt% TiO 2 was used, the entire membrane section showed agglomerates of TiO 2 nanoparticles. These polymeric membranes were tested to remove Sudan Blue II (SB) dye from aqueous solutions. The adsorption/photocatalytic processes revealed that membrane morphology and TiO 2 cluster size were the parameters that mainly affected the dye removal efficiency. Moreover, after five cycles of exposure of these membranes to UV light, SB removal was higher than 85%.