Understanding of ultrasound enhanced electrochemical oxidation of persistent organic pollutants

Advanced oxidation processes have gained attention recently due to their effectiveness in mineralizing toxic recalcitrant pollutants. In this paper, studies on combined sonolysis and electroxidation techniques have been reviewed for the degradation of the persistent organic pollutants, and real industrial wastewater. The effects of various parameters such as ultrasonic power, current density, initial pH, and electrolyte concentration have been elucidated. Critical analysis of the studies (1996-2020) on the treatment of various synthetic and real wastewater using the sono-electroxidation process has been considered. Ultrasound, in combination with electrochemical technology, is an attractive option for the treatment of industrial wastewater. The application of ultrasound gives the synergistic effect by virtue of the physical and chemical effects of cavitation. Coupling these two techniques increases the mineralization degree by increasing the mass transport rate and the chemical reaction rate, and reduce the electrode passivation and fouling problem. Woking with an optimized sonoelectrochemical reactor design with low power ultrasound with pulsed mode can remarkably decrease the energy cost and increase the economic viability of the treatment method. Challenges associated with the process are documented in this paper.