Hydrodynamic Cavitation for Micropollutant Degradation in Water - Correlation of Bisphenol a Degradation with Fluid Mechanical Properties

Abstract

The present paper deals with the correlation of degradability of bisphenol A (BPA) by hydrodynamic cavitation with fluid mechanical properties of the reactor system. The effect of inlet pressure and two orifices have been investigated. The acceleration of the flow by small orifices leads to the formation of cavitating bubble clouds in the shear layer of the jet, which implode in the cavitation reactor. The hydroxyl radicals formed during the implosion can oxidize organic compounds in water. The assessment of fluid mechanical conditions during the reaction were realized by optical measurements to determine jet length, volume of bubble area, number of bubbles and bubble size distribution. In addition, the chemiluminescence of luminol is used to localizes chemical active bubbles due to the generation of hydroxyl radicals in the reactor chamber. The correlation between the rate constants of BPA degradation and the fluid mechanical properties are discussed. Here, linear dependencies between degradability of BPA and volume expansion of bubble volume and chemiluminescence are identified, allowing a prediction of the rate constants, and produced hydroxyl radicals. Moreover, this data is useful for further reactor development for hydrodynamic cavitation in water treatment systems.

Keywords: Hydrodynamic cavitation, bisphenol A, micropollutants, fluid mechanical properties, optical measurements, chemiluminescence