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

Abstract 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 µm 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 (RhB- 80%) 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.