THE SONOLUMINESCENCE AND SONOCHEMICAL REACTIONS OF AQUEOUS SOLUTIONS

The ultrasonic irradiation of a liquid leads to the periodic growth and collapse of cavitation bubbles. The rapid collapse results in the production of high local temperatures and pressures within the bubble and the production of free radicals, leading to the emission of a faint sonoluminescence and the synthesis of chemical compounds. This work is a comprehensive study of the sonoluminescence and sonochemistry of water and aqueous solutions of carbon tetrachloride at atmospheric and elevated static pressures and at liquid temperatures ranging from 284(DEGREES)K to 362(DEGREES)K. The sonoluminescence intensity was measured with a photomultiplier and its spectral distribution was determined with interference filters.; One important finding of this work is that increasing liquid temperatures result in an exponential decrease in the sonoluminescence intensity from water. This significant result was explained by a model derived from first principles. The primary effect of liquid temperature is attributed to a change in the relative amounts of water vapor and gas in the cavitation bubble due to a change in the vapor pressure.; Another important finding is the effect of carbon tetrachloride concentration on the sonoluminescence of aqueous solutions. The sonoluminescence intensity increases linearly with the amount of CCl(,4) in solution, while the spectral distribution of the luminescence shifts towards longer wavelengths. These observations are consistent with the hypothesis that sonoluminescence is due to the recombination of free radicals (chemiluminescence) and not due to blackbody radiation.; An extensive study of the effect of static pressure on sonoluminescence is reported for water and for water saturated with CCl(,4). For both liquids, the total sonoluminescence intensity changed significantly (600%) over the pressure range of 1 - 20 atmospheres. The spectral distribution of sonoluminescence, however, showed negligible dependence on the static pressure. These important findings are explained by a change in the number of cavitation bubbles due to a change in the nucleating conditions. Another finding is the linear relationship between the sonoluminescence intensity and sonochemical yields from water saturated with CCl(,4) over the pressure range of 1 - 20 atmospheres.