Bioinspired Synthesis of Photocatalytic Nanocomposite Membranes Based on Synergy of Au-TiO 2 and Polydopamine for Degradation of Tetracycline under Visible Light.

A bio-inspired photocatalytic nanocomposite membrane was successfully prepared via polydopamine (pDA)-coated poly (vinylidene fluoride) membrane (PVDF) as a secondary platform for vacuum filtration Au-TiO2 nanocomposites with enhanced photocatalytic activity. The degradation efficiency of the Au-TiO2/pDA/PVDF membrane reached to 92% when exposed to visible light for 120 minutes. And the degradation efficiency of the Au-TiO2/pDA/PVDF membrane increased by 26% compared with that of Au-TiO2 powder, and increased by 51% compared with that of the TiO2/pDA/PVDF nanocomposite membrane. The degradation efficiency remained about 90% after five cycle experiments, and the Au-TiO2/pDA/PVDF nanocomposite membrane showed good stability, regeneration performance and easy recycling. The pDA coating not only was served as a bioadhesion interface to improve the bonding force between the catalyst and membrane substrate, but also acted as a photosensitizer to broaden the wavelength response range of TiO2. And the structure of Au-TiO2/pDA/PVDF also improves the transfer rate of photogenerated electrons. And the surface plasmon resonance effect of Au also played a positive role in improving the activity of the catalyst. Therefore, we believe that this study opens up a new strategy in preparing the bio-inspired photocatalytic nanocomposite membrane for potential waste water purification, catalysis and the membrane separation field.