Ag-loaded and Pd-loaded ZnO nanofiber membranes: preparation via electrospinning and application in photocatalytic antibacterial and dye degradation

For the efficient disposal of organic pollutants and Escherichia coli (E. coli) in water, Ag-loaded and Pd-loaded ZnO nanofibers (NFs) were prepared through electrospinning (e-spin), followed by the alcohol-thermal method. The NFs were prepared in membrane form to promote their separation, recovery, and reuse in practical applications. The complete decolorizations of three types of dyes (i.e., azo, triarylmethane, and heterocyclic dyes) were observed when the Ag-loaded or Pd-loaded ZnO nanofiber membrane (NFM) was first applied as photocatalyst under 30-min UV irradiation. The characterization of the catalysts and the decolorization performance of dyes both demonstrated that the optimal loading rates of Ag and Pd were 12% and 6%, respectively. Moreover, the 12%-Ag/ZnO NFM displayed excellent recyclability over five cycles than the 6%-Pd/ZnO NFM. The E. coli disinfection test demonstrated that the photocatalytic inactivation rates with the 12%-Pd/ZnO NFM and the 6%-Ag/ZnO NFM were significantly improved under solar or UV irradiation, and hydroxyl radicals (center dot OH) was primarily responsible for the antibacterial performance. Therefore, the presented 12%-Ag/ZnO NFM and 6%-Pd/ZnO NFM can be used for the efficient photocatalytic treatment of dyes and E. coli in water.