Hybrid PVDF-P(L-DOPA)-ZnO membranes for dyes and antibiotics removal through simultaneous action of adsorption and photocatalysis processes

PVDF-P(L-DOPA)-ZnO hybrid membranes were prepared with the purpose to eliminate several classes of pollutants from water: cationic dyes and antibiotics. The PVDF membrane with the pores mean size of 1.5 mu m was prepared by the phase inversion method. P(L-DOPA), a PDA analogue, was deposited on the polymeric membrane to facilitate the anchor of in-situ grown ZnO nanoparticles. Several characterization methods were deployed to explore the hybrid membranes' structural, morphological, optical, and photocatalytic properties. The firm P(L-DOPA)-ZnO coating on the PVDF membrane surface converted its hydrophobic nature to a hydrophilic one. For an optimal ZnO nanoparticles amount and size, efficient degradation of Rhodamine B (RhB80%) and oxytetracycline (OTC-71%) was obtained in 5 h of UV-light irradiation. The generation of P(L-DOPA)ZnO Z-scheme photocatalyst promotes an efficient separation of photoinduced electron-hole pairs beneficial to photocatalytic activity. The hybrid membrane revealed similar photocatalytic activity after 3 cycles illustrating high stability. The analysis of the generated reactive oxygen species correlated with radical spin trapping experiments suggest that photogenerated h+ play the main role in the photodegradation of both studied pollutants.

Automated summary

The PVDF-P(L-DOPA)-ZnO hybrid membrane effectively removed cationic dyes and antibiotics from water through structural modifications and improved photocatalytic properties. The efficient separation of photoinduced electron-hole pairs promoted photocatalytic activity, leading to high stability even after 3 cycles of use.