Evaluating the synergistic effect of UVC/e-H2O2 applied for benzotriazole degradation in water matrices using catalyst-free printex L6 carbon-based gas diffusion electrode

Abstract

The present work investigated the application of UVC combined with electrogenerated H₂O₂ (UVC/e-H₂O₂) for BTA degradation using a Printex L6 carbon-based (PL6C) gas diffusion electrode (GDE). The studies were carried out by analyzing the influence of the current density, pH and initial BTA concentration in the contaminant degradation process. Under optimal conditions using 0.05 mol L⁻¹ K₂SO₄ as supporting electrolyte, BTA removal was evaluated in different water matrices. In all cases, 100% of BTA elimination was reached in the first 15 minutes of treatment under the UVC/e-H₂O₂ process, while mineralization rates ranging between 59.2 and 78.0% were obtained after 90 minutes of electrolysis. The active species O₂^•- and e^- played an important role in the BTA removal. The toxicity test conducted on the river water sample post-treatment using the Lactuca sativa L seeds showed that the BTA by-products had low toxicity. The results obtained from the LC–ESI–MS/MS analyses showed the same BTA degradation by-products when the BTA-containing water matrices were treated using the UVC/e-H₂O₂ and photo-electro-Fenton processes. The PL6C-GDE developed in the study exhibited high efficiency when applied for H₂O₂ electrogeneration and BTA degradation. Additionally, the electrode demonstrated remarkable stability and durability, enabling the generation of reproducible data for up to 81 hours of continuous operation.