Photocatalytic degradation of atrazine in aqueous solution using La-doped ZnO/PAN nanofibers.

Abstract

Polyacrylonitrile (PAN)-based-modified zinc oxide (ZnO) nanofibers were synthesized by using electrospinning and hydrothermal techniques. The synthesized nanofibers were characterized by field emission scanning electron microscopy and X-ray photoelectron spectroscopy and evaluated for their ability to promote the photocatalytic degradation of the toxic herbicide atrazine. The degradation conditions were optimized by varying catalyst types, catalyst quantity, pH, light source, and toxic concentration. The degradation products were confirmed by high-performance liquid chromatography and gas chromatography-mass spectrometry (GC-MS) analyses. The extent of mineralization was calculated using total organic carbon and real-time analyses. The diameter of the La-doped ZnO-loaded PAN nanofibers was larger than that of the ZnO-seeded PAN nanofibers. The additional peak at a binding energy of 533eV in the bonding states of La-doped ZnO/PAN indicated the presence of oxygen vacancies in the ZnO matrix, which could enhance the catalytic activity of the material. Furthermore, the degradation of atrazine depended on all the above reaction parameters. The mass spectrum of the degradation product was recorded and exhibited a molecular ion peak at m/z 187 according to GC-MS. Finally, La-doped ZnO PAN nanofibers proved to be an excellent catalyst for decontaminating atrazine within 1h and allowed to achieve a 98% degradation efficiency.