Dependence of the rate of formation of nitrate ions in water on the intensity and frequency of ultrasound waves

Autor: M. A. Margulis, I. M. Margulis
Rok vydání: 2009
Předmět:
Zdroj: Russian Journal of Physical Chemistry A. 83:2233-2237
ISSN: 1531-863X
0036-0244
DOI: 10.1134/s0036024409130093
Popis: The dependence of the rate of the sonochemical formation of nitrate ions in water saturated with air on the intensity (within 0–2.5 W/cm2) and frequency (20–1600 kHz) of ultrasound waves was studied. The acoustic power was measured by the comparative calorimetric method. The reaction was conducted in the kinetic region, where the reaction rate was independent of the rate of mass transfer processes, such as the degasification and stirring of the solution and the depletion of the reactants, being determined only by the formation of radicals in cavitation bubbles. It was demonstrated that, within the indicated range of ultrasound frequencies, the dependence of the reaction rate on the ultrasound intensity behaved as follows: at intensities below 0.1–0.2 W/cm2, the w(I) dependence is nonlinear and can be roughly approximated by a quadratic function; at I > 0.2 W/cm2, w(I) becomes linear. This behavior can be explained in the following way: at I 0.2 W/cm2). The K(f) dependences passes through a maximum at a frequency of f ∼ 100 kHz; at frequencies of f > 500 kHz, K ∼ f −1.
Databáze: OpenAIRE
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