Mass-transfer studies in a parallel-plate electrochemical reactor with ultrasonic assistance under single-phase and two-phase (gas-evolving) flows

The paper reports an experimental and theoretical study of the application of ultrasound to an electrochemical reactor with parallel-plate electrodes. The ultrasonic operation improves the mass-transfer performance of the device related to the silent case. Thus, the mean mass-transfer coefficient can be enhanced by a factor ranging from 1.1 to 2.3, and also the mass-transfer distribution along the electrode length becomes more uniform than for silent operation. The improvement of the mass-transfer performance is more marked at small interelectrode gaps and low superficial flow velocities of the electrolyte. A mathematical model is reported that can predict quite well the behaviour of this kind of devices. The application of ultrasound to electrochemical reactors can be recognised as a promising strategy to improve their performance.