Photocatalytic degradation of oxytetracycline by SiO2–TiO2–Ag electrospun fibers

Abstract

The contamination and dispersion of antibiotics into the environment through effluents from sewage treatment plants have produced serious consequences like the generation of resistant bacteria, generating a health emergency, so the need arises to develop processes to eliminate antibiotics in effluents. One of the methodologies used is advanced oxidation where a complete degradation of antibiotics can be reached, among the advanced oxidation processes, photocatalysis stands out as an efficient degradation pathway of organic pollutants from a photocatalyst. In the present investigation SiO2–TiO2 fibers were obtained by sol-gel and electrospinning techniques which had a cylindrical morphology and a smooth surface free of defects with a diameter 266 ± 62 nm. In increasing photocatalytic properties, the SiO2–TiO2 fibers were doped with silver by electrodeposition resulting in the deposition of particles with a branched dendritic morphology with a size of approximately 1 μm. The characterization of SiO2–TiO2–Ag fibers by infrared in the fibers eluted bands characteristic of the Si–O–Si and Ti–O–Ti bonds, and by means of the X-ray diffraction were identified crystalline phases corresponding to the anatase and rutile of the Titania, as well as face-centered cubic silver. Oxytetracycline was used as a contaminant to investigate the photocatalytic performance of SiO2–TiO2–Ag material, where from an initial concentration of 30 ppm in the presence of SiO2–TiO2 fibers its degradation percentage was 65%, unlike 90% in 7 h using silverdoped fibers. The increased degradation of oxytetracycline is attributed to the success in decreasing the banned band of SiO2–TiO2 fibers from 3.1eV to 2.5eV to silver doping.