P15 ソノルミネッセンス強度の低下に対するアルコール添加の影響

抄録

Multi-bubble sonoluminescence spectra from Ar-saturated water with 2 mM alcohol (methanol, ethanol, 1-propanol, and 1-butanol) acting as radical scavengers were measured over 257-540 nm for different durations. 10 W of acoustic power was used (measured by calorimetry) at an ultrasonic frequency of 410 kHz. Addition of alcohol to the water dampened the multi-bubble sonoluminescence intensity. The sonoluminescence (continuum emission and OH radical emission) intensity decreased with increasing irradiation time. The decreasing rate of sonoluminescence was enhanced when more hydrophobic 1-butanol was added. In addition, when Ar-saturated water containing more hydrophobic 1-butanol was sonicated, larger amounts of gaseous products were generated. When less hydrophobic methanol was used instead of 1-butanol, not only decreasing rate of sonoluminescence, but generation of gaseous products were depressed. In conclusion, the decrease in sonoluminescence intensity with increasing irradiation time was attributed to the degradation products of alcohols, and depends upon the hydrophobicity of the added alcohols.