Preparation and characterization of Cu2O nano-particles and their photocatalytic degradation of fluroxypyr.

Cu2O nano-particles were prepared by the liquid-phase reduction method and the effect of the dispersant was studied. The microstructure, surface morphology and optical properties of Cu2O nano-particles were characterized by X-ray diffractometer, X-ray photoelectron spectroscopy, nitrogen static adsorption, scanning electron microscope, particle size analysis, ultraviolet visible light spectrophotometer and photoluminescence spectrometer. The photocatalytic degradation of fluroxypyr using Cu2O was studied by the response surface methodology, and the quadratic multinomial mathematical model was established. The results indicated that the Cu2O crystal particles prepared using the dispersant of polyvinylpyrrolidone were of high purity with the preferential orientation of (111). The average particle size was 605.4 ± 124.8 nm, the specific surface area was 22.641 m2/g, the band gap was approximately 2.04 eV and the absorption edge was about 650 nm. R2 of the established quadratic model was 0.9973 and had good fitness, indicating that the established model was reliable. The optimal degradation conditions were obtained as follows: the initial concentration of fluroxypyr was 11.17 mg/L, the pH of the solution was 12.0 and the H2O2 concentration was 15 mg/L. The degradation rate of fluroxypyr could reach 83.2% and the relative error was 1.20%. After nine times of recycling, more than 75% of fluroxypyr could be degraded.