Search

Pumice-loaded CeO/BiWO photocatalysts were prepared with a typical solvothermal method by using pumice as the macroporous carrier. The photocatalysts were characterized by X-ray diffraction, scanning electron microscopy, energy dispersive spectrometry and element mapping. The preparation conditions were optimized and the photoactivity was evaluated via photocatalytic tetracycline degradation under visible light radiation. Moreover, the photocatalysts were applied to a continuous flow reactor and the optimal conditions were studied. It was found the CeO/BiWO catalysts were successfully loaded on the surfaces and pores of pumice. The optimal catalyst/pumice loading ratio was 1:4 mmol/g, and the average load rate of the photocatalysts was 37.24%. Under visible-light irradiation, the pumice-loaded CeO/BiWO catalysts could well photocatalytically degrade tetracycline, with a degradation rate within 90 min up to 91.72%, and were stable photocatalytically. Experiments with the continuous flow reactor showed the optimal catalyst quantity, light source intensity, pollutant concentration and hydraulic retention time were 10 g/L, 140,000 lx, 50 mg/L and 6 h, respectively, when the tetracycline degradation rate was stably improved to 90.00%. [ABSTRACT FROM AUTHOR]

Enhanced visible light photocatalytic activity of BiWO photocatalyst modified with different ratio of polyvinyl pyrrolidone (PVP) was synthesized by a facile solvothermal process. The as-prepared photocatalysts were characterized by X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, UV-Vis diffuse reflectance spectra and photoluminescence spectra. The results indicated that the addition of PVP could control the particle morphology of bismuth tungstate catalyst to form high phase purity of BiWO. The solvent-thermal reaction time was critical in deciding the structure and shapes of the catalysts, and the optimal solvent-thermal reaction time was 24 h. The photocatalytic activities of the PVP-BiWO catalysts were determined by photocatalytic degradation of tetracycline hydrochloride (TCH) in aqueous solution under visible light irradiation. Optical properties and the TCH degradation results showed that PVP-BiWO catalysts exhibited enhanced photodegradation for TCH under visible-light irradiation. Among them, P5 (PVP % = 1.0 wt%) exhibited the best photocatalytic activity for degradation ratio of TCH reaching 86.88 % in 90 min. [ABSTRACT FROM AUTHOR]