Laboratoire Chimie Moléculaire et Environnement, Université de Savoie, 73376 Le Bourget du Lac, France.
Ultrason Sonochem. 2012 Mar;19(2):280-5. doi: 10.1016/j.ultsonch.2011.07.009. Epub 2011 Aug 5.
The aim of this study was to evaluate the effects of liquid height and frequency on sonochemical efficiency of a cup-horn sonoreactor. The selected frequencies (22, 371, 504 kHz) and liquid height (29-348 mm) were applied while measuring acoustic yield, I(3)(-) formation rate and the resulting sonochemical efficiency. The frequency effect was shown to be coupled to liquid height effect. Indeed, acoustic zones (i.e. Fresnel and Fraunhöfer zones), which limits depends on both transducer diameter and frequency, significantly determine the production of radicalar species quantified by I(3)(-) formation rate. An increase of ultrasonic frequency results in lower acoustic yield and higher sonochemical efficiency. Theoretical physical and chemical effects attributed to collapsing bubbles were considered. Sonochemical efficiencies obtained at 500 kHz were similar or higher than those at 371 kHz, depending on liquid height. The effect of reactor configuration was further investigated as an hypothesis to explain unsignificant effect of standing waves in our study. Therefore, the dependence of sonochemical efficiency with liquid height might be firstly attributed to reactor configuration prior to frequency effects.
本研究旨在评估液体高度和频率对杯形号角声反应器声化学效率的影响。在测量声产率、I(3)(-)生成速率和相应的声化学效率时，选择了 22、371 和 504 kHz 的频率以及 29-348 mm 的液体高度。频率效应与液体高度效应相关联。实际上，声区（即菲涅尔区和夫琅禾费区），其限制取决于换能器直径和频率，显著决定了通过 I(3)(-)生成速率定量的自由基种类的产生。超声频率的增加导致声产率降低和声化学效率提高。考虑了归因于空化泡崩溃的理论物理和化学效应。在 500 kHz 下获得的声化学效率与在 371 kHz 下获得的声化学效率相似或更高，这取决于液体高度。进一步研究了反应器构型的影响，作为在我们的研究中驻波无显著影响的假设。因此，液体高度对声化学效率的依赖可能首先归因于频率效应之前的反应器构型。
