Study on the Physical Mechanism of Rhodamine B Degradation by Ultrasonic Cavitation Effect

Abstract

The growing environmental challenge posed by textile effluents has driven the search for effective and sustainable treatment technologies. Ultrasonic degradation has emerged as a promising approach due to its ability to break down organic pollutants without introducing secondary contamination. However, the underlying physical mechanisms remain insufficiently understood, limiting the optimization of energy efficiency in practical applications. To address this gap, this study employs Rhodamine B (Rh B) as a model pollutant to investigate the fundamental principles governing ultrasonic degradation through a multi-faceted approach. First, the cavitation activity of the acoustic field under varying ultrasonic parameters is quantitatively evaluated using potassium iodide (KI) dosimetry. Second, systematic experiments are conducted to examine the synergistic effects of acoustic field intensity, sonication time, ultrasonic frequency, and power on the degradation efficiency of Rh B. Third, theoretical and numerical simulations are performed to analyze the nonlinear oscillation behavior of a single cavitation bubble and its influencing factors, thereby elucidating the physical mechanisms driving degradation. The experimental results reveal that bubble oscillation-induced cavitation generates localized high temperatures and pressures, which facilitate the cleavage of molecular bonds in Rh B. The degradation rate exhibits a positive correlation with both cavitation activity and acoustic field intensity, synergistically modulated by the operational parameters. A key novelty of this work lies in establishing an explicit correlation between parametric experimental results and detailed bubble dynamics simulations, providing mechanistic insights that extend beyond phenomenological observation. Together, these findings offer a theoretical and experimental foundation for optimizing energy efficiency in the ultrasonic degradation of organic pollutants.