Method for determining the chemically active zones in a high-frequency ultrasonic reactor

In order to determine the optimal geometry of the high-frequency sonoreactors to be used for degradation of organic compounds in aqueous solutions, a method based on the chemiluminescence of luminol (which reacts specifically with OH radicals) is applied to visualize the zones where the sonochemical reactions are the most active. The spatial distribution of the light intensity emitted by these reactions is measured inside the reactor with an optical fibre fitted on a photomultiplier. To determine the relative ultrasonic energy distribution, the temperature is measured at different points of the reactor with a thermocouple probe embedded in an absorbing material. The zones where the energy density is the highest were shown not to correspond with those where chemiluminescence reactions are the most efficient.