Rare earth lanthanum doped catalyst for photocatalytic degradation of fleroxacin

The production and abuse of fluoroquinolones have caused enormous environmental pollution, and there is an urgent need for a simple and efficient method to solve this problem. In this paper, a rare earth lanthanum doped nanocomposite catalyst was synthesized. The dendritic structure of graphite carbon nitride (g-C3N4) can better wrap polypyrrole (PPy) and titanium dioxide (TiO2). The composite material was observed to be aggregated under electron microscope. TiO2 and PPy with sizes of approximately 10 and 100 nm, respectively, are evenly distributed in the pore-rich material. On the surface of the composite, there are abundant with a pore diameter of 3.75 nm. The introduction of rare earth La provides a new energy level for the band gap of TiO2 and g-C3N4 matrix composites. And the band-gap energy (Eg) reached 2.63 eV. La can promote electron hole separation and inhibit its recombination, thereby improving the photocatalytic property. The degradation rate of TGPL to FLE reached 81%. In addition, ultra-performance liquid chromatography tandem mass-spectrometry (UPLC-MS) analysis of the degradation of antibiotic fleroxacin (FLE) by this catalyst showed that the piperazine ring and the N1 side chain first reacted, and then gradually degraded. This study provides a broad prospect for the preparation of highly efficient photocatalysts.