Opto-isolation of electrochemical systems in cavitation environments

An electrochemical technique that can detect inertial cavitation within an ultrasonic reactor is reported. The technique relies on the erosion and repassivation of an oxide covered electrode (specifically aluminum). The sensitivity of the technique (<46 fg per erosion event) is significantly greater than normal weight loss measurements. A novel opto-isolation system is discussed which enables the electrochemical measurements to be undertaken within an earthed metallic container. Events detected in this manner are reported and compared to the noise in the absence of appropriate isolation. This system is combined with a multichannel analyzer to map the erosion/corrosion activity within an operating ultrasonic bath.