4. Conclusion

Of all the industrial fields in which ultrasound is traditionally used, cleaning is undoubtedly the most outstanding example. From a sonochemical point of view, ultrasonic wave applications are rare. Even if the use of this technology in the fields of fine chemistry, synthetic chemistry, specialty chemistry and environmental chemistry is well known, in the vast majority of cases it is based on know-how that remains confidential. Indeed, transposing promising laboratory results to industrial scale is no easy task. The design of sonochemical reactors calls on many disciplines: acoustics, physics, process engineering and chemistry. What's more, dimensioning is not governed by conventional rules, since the effects induced by ultrasonic irradiation are directly dependent on acoustic cavitation, the major phenomenon underlying sonochemistry. So it's above all the choice of the right frequency...