Comparative performance of ultrasonic reactors configurations for ibuprofen removal

The application of ultrasound-based technologies for the degradation of emerging contaminants in water is gaining increasing attention due to their ability to enhance radical formation and promote efficient oxidation pathways [1,2]. In this study, two ultrasonic configurations—a probe-type horn and a Meinhardt Ultrasonics reactor—were employed to investigate the degradation of ibuprofen (IBU), a widely used and persistent non-steroidal anti-inflammatory drug, in aqueous media. The oxidative processes were performed in the absence and in the presence of bismuth oxybromide (BiOBr) as a visible-light-responsive photocatalyst, under three operating modes: sonocatalysis, photocatalysis, and their synergistic combination (sonophotocatalysis). The performance of each approach was compared in terms of IBU removal efficiency. To assess the environmental relevance of the process, UHPLC-MS/MS analyses were carried out to identify the transformation products (TPs) formed during the processes. Several intermediates were structurally proposed based on MS and MS/MS fragmentation patterns. The findings provide insight into the reaction pathways and potential environmental impact of the resulting TPs. This work underscores the promising role of ultrasound-driven advanced oxidation processes (AOPs) in the sustainable treatment of pharmaceutical contaminants. [1] Galloni, M.G. et al., Applications and applicability of the cavitation technology, Curr. Opin. in Chem. Engin., 2025, 48, 101129. [2] Falletta, E. et al., Fast and Efficient Piezo-Photocatalytic Mineralization of Ibuprofen by BiOBr Nanosheets under Solar Light Irradiation, ACS Photonics 2023, 10, 3929−3943.