Limitations of the Weissler reaction as a model reaction for measuring the efficiency of hydrodynamic cavitation

The Weissler reaction in which iodide is oxidised to a tri-iodide complex (I3−) has been widely used for measurement of the intensity of ultrasonic and hydrodynamic cavitation. It was used in this work to compare ultrasonic cavitation at 24 kHz with hydrodynamic cavitation using two different devices, one a venturi and the other a sudden expansion, operated up to 8.7 bar. Hydrodynamic cavitation had a maximum efficiency of about 5 × 10−11 moles of I3− per joule of energy compared with the maximum of almost 8 × 10−11 mol J−1 for ultrasonic cavitation. Hydrodynamic cavitation was found to be most effective at 10 °C compared with 20 °C and 30 °C and at higher upstream pressures.However, it was found that in hydrodynamic conditions, even without cavitation, I3− was consumed at a rapid rate leading to an equilibrium concentration. It was concluded that the Weissler reaction was not a good model reaction for the assessment of the effectiveness of hydrodynamic cavitation.