离子溅射银对光电协同灭青霉菌的影响

为解决果蔬采后易受微生物作用而腐败变质的问题,该文进行了纳米二氧化钛(TiO_2)光催化技术灭活园艺产品冷藏环境中青霉菌的研究:以活性炭纤维(activated carbon fiber,ACF)为载体,以粉末浸渍-提拉法制备TiO_2-ACF薄膜,采用离子溅射法在ACF薄膜上作贵重金属银沉积处理,研究表面溅射与底层溅射纳米Ag粒子及施以外加电压处理对TiO_2-ACF薄膜光催化灭活青霉菌的影响及机理。结果显示,不同的溅射方式对试验结果有不同的影响,其中底层溅射效果较好,120 s时光催化灭活青霉菌速率最高;外加电压可提高TiO_2-ACF薄膜光催化速率,75 V是最优值,且光电催化作用效果优于单独光催化和电催化的总和。对负载的ACF薄膜表征分析,发现离子溅射较均匀地实现了纳米Ag-TiO_2混合粒子在ACF薄膜的表面及内部负载。研究结果为纳米TiO_2光催化技术在灭活园艺产品冷藏环境中青霉菌的实际应用提供参考。

Effect of ion sputtering Ag on photoelectric synergism for disinfection of Penicillium

Horticultural products are easy to be infected by microorganisms, which often causes great waste of resources and huge loss of economy, so it is imperative to inhibit the activity of the microorganisms in the storage environment of the harvesting horticultural products. As the representative of the Penicilliumfungal infection is a major cause for decayed fruits and vegetables, fungaltoxin derived from Penicillium will do huge harm to people with strong stability and cancerigenic toxin after infecting vegetables and fruits. In this article, we did some research about how to use nano titanium dioxide (TiO2) to inhibit the activity ofPenicillium fungus in simulated refrigeration environment. NanoTiO2 is a new type of nano semiconductor material, which is widely concerned due to its special properties. When irradiated by excited light, TiO2 would generate electron-hole pairs, then the pairs could produce ?O2- and free radicals (HO?) with high oxidative activity, which can degrade most organic compounds to non-toxic CO2 and H2O. They also have direct effect on bacteria , leading to cell death. However, the photo electrons and holes are very easy to be combined, which makes the high redox activity lost. This experiment was carried out from two aspects: heavy metals modifying and voltage applying. It was found that heavy metals could change the distribution of the electrons in the surface of TiO2, this could reduce the electron-hole pair of the composite probability and improve the quantum effect of TiO2. When using TiO2 film electrode photo-catalyst to degrade the organic compounds through applying a small positive voltage between the electrolytic tank poles, it could drive the photo-induced electrons in anode to flow to cathode, and reduce the chance of combination of electrons and holes, resulting in high concentration of hydroxyl radicals and improving the degradation efficiency of organic pollutants. In this study, we choose the activated carbon fiber (ACF) as carrier, nanoTiO2 with heavy metal nano-Ag deposition (Ag-TiO2/ACF) were prepared by ion sputtering. The effect of TiO2-ACF with heavy metal Ag modification on the photoelectric synergism for disinfection of Penicillium was also invested. The results showed that the different sputtering treatment in experiments presented different effects, and the underlying sputtering exhibited the best performance. The apparent rate constant of Penicillium disinfection reached the highest at 120 s which increased by 39.4% comparing with the contrast. On the other hand, applied voltage can significantly improve thePenicillium disinfection rate of TiO2-ACF film, but less significant improvement for the Ag-ACF/TiO2 film. The optimal value are 75 V, and photoelectric synergism effect in this case is better than the use of photo-catalyst or electro-catalyst separately. It can be found that ion sputtering achieved the well distribution of Ag-TiO2 particles on the surface and inside of ACF film when analyze the characterization of ACF film.