The effect of ultrasound on water in the presence of dissolved gases

Abstract

Sonolysis of water at 447 kHz causes a decrease in the pH. The products formed depend to some extent on the nature of the dissolved gases; products observed are hydrogen peroxide, nitrous and nitric acid. The yield of hydrogen peroxide follows the order O 2 > air > Ar > N 2 . In the case of total acid (nitrous and nitric) the yield follows the order air >N 2 > Ar > O 2 . Nitrogen fixation occurs in the presence of Ar and O 2 because of the presence of small amounts of N 2 either as an impurity in the dissolved gases, or as residual air in the incompletely degassed water.An attempt was made by using the Fricke dosimeter to obtain information on the relative chemical activity of cavitation.