Cavitation characteristics of a novel self-excited oscillating hydrodynamic cavitation reactor for Rhodamine B removal

Hydrodynamic cavitation (HC) is an emerging advanced oxidation technology with great potential for water treatment and environmental remediation. In this study, the cavitation behavior and degradation performance of Rhodamine B in a self-excited oscillating hydrodynamic cavitation system were systematically investigated. Flow visualization analysis revealed the coexistence and dynamic evolution of attached cavitation, detached cavitation, and vortex cavitation under different operating conditions. The degradation results demonstrated that increasing flow rate, decreasing solution pH, and lowering initial pollutant concentration significantly enhanced Rhodamine B removal. When HC was coupled with the Fenton process, a pronounced synergistic effect was observed, achieving a maximum degradation efficiency of 96.34%, which was substantially higher than that of the conventional Fenton process alone. This enhancement confirms the effectiveness of hydrodynamic cavitation in intensifying advanced oxidation processes. Further analysis indicated that jet deflection-induced transitions among different cavitation patterns promoted the formation of detached and vortex cavitation, which were identified as the dominant contributors to the improved degradation performance. These findings provide mechanistic insight into the role of cavitation characteristics in pollutant degradation and highlight the potential of HC-assisted oxidation processes for efficient wastewater treatment.