Combined Application of Ultrasound with Electrochemistry

The advantages of using ultrasound in the electrochemistry of organic compounds has been reviewed elsewhere [40]. The combination has been found to be particularly useful in the destruction of chemical pollutants. It has been applied to the destruction of phenols by electrochemical oxidation. Ultrasound (25 kHz, lO W m ) when applied 

Sonoelectrochemical destruction of dyes has also been investigated. Solutions of the acidic dye Sandolan Yellow have been decolourised by a sonoelectrochemical process in aqueous saline solution using platinum electrodes [42]. The process entails the electrolysis of aqueous NaCl solution which involves the liberation of chlorine at the anode and hydroxide ion at the cathode. The overall cell reaction is  

The rate of electrochemical decolourisation in the absence of ultrasound was dependent on the electrolyte concentration, reaction temperature and the current density. 

The rate was enhanced using ultrasound when carried out in a semi-sealed cell, which minimised the effects of ultrasonic degassing. An optimum acoustic power was found when using a source at a frequency of 20 kHz. 

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