Degradation method for the antiepileptic drug primidone in water using a hybrid high-frequency ultrasound and photo-Fenton process

Antiepileptic drugs are considered contaminants of emerging concern in water and are resistant to conventional wastewater treatment processes. Therefore, their presence has been detected in surface waters, and their elimination/degradation requires effective treatment methods. In this research, ultrasound-based methods (e.g., sonolysis, sono-Fenton, and sono-photo-Fenton) were addressed in the degradation of antiepileptic drug primidone at laboratory scale. A high-frequency ultrasound (at 578 kHz and 20.4 W) was applied. Then, Fe²⁺ ions (5 mg l^-1) and a UVA lamp (4 W) were added to the sonochemical reactor. After 75 min of treatment, the sono-photo-Fenton method showed better degradation efficiency (93 %) than the sono-Fenton (83 %) and sonolysis (62 %) methods. Finally, the effectiveness of the degradation method by sono-photo-Fenton was tested in simulated pharmaceutical wastewater, degrading 72 % of primidone at 75 min of treatment, indicating matrix effect plays a role in the degradation (which could be a potential application of ultrasound hybridized with the photo-Fenton process).•Three ultrasound-based treatment methods were applied to degrade primidone in water.•The sono-photo-Fenton method degraded 93 % of primidone during 75 min of treatment.•The matrix influence on primidone degradation by sono-photo-Fenton was evaluated.