Sonochemistry: Scope, limitations ... and artifacts

Heterogeneous sonochemistry, generally described as the most useful aspect of sonochemistry, suffers from the difficulty of defining the experimental conditions for the reference (silent) reaction. Clearly the use of an efficient agitation system for the silent reaction strongly reduces the value of the so-called sonochemical effect, which becomes in some cases, less than 1 (anti-sonochemical effect!). The 'cleaning' effect of ultrasound is extremely efficient to expel micro-crystals from the surface of an electrode which is simultaneously an immersion ultrasonic horn. By sending out-of-phase electric pulses and acoustic pulses, new nano materials (metals, alloys, semiconductors, oxides) ave easily prepared in high purity.