Ultrasound assisted chemical processes

Ultrasound, when passed through a liquid medium, causes physical perturbations and chemical reactions. There is a growing interest in exploiting these ultrasound induced events for useful applications. The primary and secondary radicals generated by the ultrasound induced cavitation events have been used, to decompose organic pollutants in aqueous medium, to synthesise metal particles, semiconductors and polymers in aqueous and non-aqueous media. Some of the metal particles exhibit higher efficiency towards certain catalytic reactions compared with standard commercial samples. Increased efficiency in certain synthetic organic reactions have been achieved using ultrasound. Electrochemical reactions are found to be affected mainly by the physical effects (such as electrode surface cleaning, increased mass transport, etc.) caused by the ultrasound. Ultrasonic cleaning processes are aided by both the cavitation events and the mechanical effects of the ultrasound.