Department of Chemical and Biomolecular Engineering, Wallace H. Coulter School of Engineering, Clarkson University, Potsdam, NY 13699, USA.
Ultrason Sonochem. 2013 Jan;20(1):618-25. doi: 10.1016/j.ultsonch.2012.08.002. Epub 2012 Aug 24.
The present manuscript compares the ultrasonic degradation of Rhodamine B dye under atmospheric (1 bar) and elevated pressures (1.6 and 2 bar). The degradation was studied as a function of the bulk liquid temperature and initial dye concentration at two different values of mechanical amplitudes (ultrasonic intensities). Results indicate that at the low amplitude an increase in the applied pressure increases the dye removal rate, whereas at the high amplitude, the same increase in the pressure has a minimal effect on the degradation of the dye. Furthermore, at low amplitudes an increase in the bulk liquid temperature from 5 to 35 °C increases the dye degradation by 10%. At higher intensities, the same increase in temperature has negative or no effect on the dye removal. An increase in the initial dye concentration by one order of magnitude significantly lowers the dye degradation rate regardless of the applied amplitude. Though these results are caused by numerous physical and chemical processes taking place during ultrasonic cavitation, the number of cavitation sites, bubble temperature and consequently, the amount of oxidative species inside the bubble seem to be the most important ones in determining the extent of the degradation of molecules in the bulk liquid.
本手稿比较了在大气（1 巴）和升高压力（1.6 和 2 巴）下罗丹明 B 染料的超声降解。降解作为液体温度和初始染料浓度的函数在两种不同的机械幅度（超声强度）下进行了研究。结果表明，在低幅度下，施加压力的增加会提高染料去除率，而在高幅度下，相同的压力增加对染料的降解影响最小。此外，在低幅度下，液体温度从 5°C 升高到 35°C 会使染料降解增加 10%。在更高的强度下，相同的温度升高对染料去除没有负面影响或没有影响。初始染料浓度增加一个数量级会显著降低染料降解速率，而与施加的幅度无关。尽管这些结果是由超声空化过程中发生的众多物理和化学过程引起的，但空化位点的数量、气泡温度以及因此气泡内氧化物种的数量似乎是决定液体中分子降解程度的最重要因素。
