Ultrasonic cavitation is well known to be applicable to the indecomposable waste such as chlorinated hydrocarbons on the waste treatment. In order to apply the sonochemical method to the treatment of wastewater including soil, the effects of particle properties on the sonochemical decomposition is experimentally investigated. The ultrasonic frequency was 22.8 kHz. The sample to be decomposed was porphyrin in aqueous solution. The dimensions of reactor were 110 mm in diameter and 140 mm in height. The volumes of samples were changed between 960 x 10'3 m3. The particles used in this study were spherical silica and alumina ones. The particle concentration and the particle diameter were changed. The sample was tetraphenylporphine tetrasulfonic acid aqueous solution. The porphyrin concentration in the sample was determined by using a UV spectrometer. As a measure of liquid mixing behavior, the liquid mixing time in the reactor was measured. Under ultrasonic irradiation, the recirculation of the particles enhances the liquid mixing in the reactor and the decomposition of porphyrin. Under the presence of particles the decomposition of porphyrin by ultrasonic irradiation proceeds at the first order reaction as in the case without particle. The decomposition reaction rate constant depends on the concentration and material of particles. It is considered that silica particles enhance the formation of cavities.
