Comparison of hydrophilic PVA/TiO₂and hydrophobic PVDF/TiO₂microfiber webs on the dye pollutant photo-catalyzation

In this paper, hydrophilic PVA/TiO2 and hydrophobic PVDF/TiO2 microfibrous webs with varied TiO2 concentrations (0 %, 1 %, 3 %, 5 %, 10 %, and 20 %) were produced by the electrospinning technique. UV-vis spectrums were tested to demonstrate the photocatalytic properties of PVA/TiO2 and PVDF/TiO2 webs under visible light. Overall, PVDF/TiO2 exhibits higher Rhodamine B (RhB) decomposition efficiency than PVA/TiO2 samples. Specifically, RhB of around 50 % and 80 % were degraded by 13 d and 49 d for PVA/TiO2 samples with TiO2 of 10 %. RhB of around 50 % and 100 % were degraded at 3 h and 49 d for PVDF/TiO2 samples with TiO2 of 10 % and 20 %. Furthermore, the degradation rate for PVA/TiO2 and PVDF/TiO2 with TiO2 of 10 % is around 0.11 and 0.23. The difference in RhB photodegradation mechanism of PVA/TiO2 and PVDF/TiO2 webs was described and discussed in this paper. Hydrophobic PVDF/TiO2 was suspended in RhB liquid and ensured maximum contact between RhB pollutants and TiO2, whereas PVA/TiO2 completely dissolved in RhB liquid, which decreased the contact area and caused secondary pollution. In conclusion, hydrophobic PVDF/TiO2 webs with TiO2 of 10 % were suitable candidates for RhB photodegradation compared to PVA/ TiO2 webs.