超声波技术在纳米TiO_2制备和光催化中的应用

Application of ultrasonic technology in preparation and photocatalysis of nano-TiO_2

介绍了超声波的空化效应、机械效应、热效应及化学效应,以及超声波辅助纳米TiO2的制备方法:超声雾化法、超声水解法、超声波溶胶-凝胶法.综述了超声波技术在纳米TiO2粉体制备、分散及光催化降解有机污染物中的应用.实验结果表明:超声波产生的空化效应,不仅可引起局部高温高压等极端环境,而且产生了大量的高活性自由基,可将有机污染物分解掉.超声波产生的机械效应具有分散催化剂、清洗催化剂的表面、强化传质等作用,能够促进光催化反应.但是,超声波辅助纳米TiO2现仅限于实验室研究,尚未实现工业化应用.而且,超声波辅助纳米TiO2的研究尚存在诸多问题,亟待进一步研究.

Cavitation,mechanical,thermal,and chemical effects of ultrasound were introduced.The meth-ods ultrasound-assisted preparation of nano-TiO2 including ultrasonic atomization,ultrasonic hydrolysis and ultra-sonic sol-gel methods were also introduced.The application of ultrasonic technology in preparation and disper-sion of nano-TiO2 powder and its photocatalytic degradation of organic pollutants was reviewed.The results showed that the cavitation effect generated from unltround could not only give rise to local high temperature and pressure extreme environment, but generate huge high activity free radicals, which could degrade organic pollutants. The mechanical effect produced by ultround could disperse catalyst, clean the surface of catalyst, strength- en the mass transfer, which could promote the photocatalytic reaction. However, the study on ultrasonic-assisted nano-TiO2 still limited in the lab, its industrial application was not be realized. Meanwhile, there are some problems in ultrasonic-assisted nano-TiO2, which still needs further study.