Integrated bio-electro-Fenton approach for efficient removal of the antiviral sofosbuvir in aqueous medium: kinetics, parameters optimization, mineralization pathway, and biodegradability enhancement

Abstract

The accumulation of antiviral drugs, such as sofosbuvir (SOF), in aquatic environments raises growing concerns due to their persistence and potential ecological risks. This study addresses the need for effective degradation strategies by investigating the homogeneous electro-Fenton (EF) process in a Pt/carbon felt cell for the degradation and mineralization of SOF in an aqueous medium. A Box-Behnken design (BBD) was employed to optimize key operational parameters, including initial Fe2+ concentration, current intensity, and initial SOF concentration, targeting chemical oxygen demand (COD) removal as the main response. The model showed excellent predictability (R2 = 0.99), and the optimal conditions were identified as 400 mA current intensity, CSOF-0 = 0.1 mM, and CFe2+-0 = 0.1 mM. Under these conditions, 97% of SOF was degraded within 5 min, while complete mineralization was achieved within 5 h. Biodegradability tests revealed an increase in the BOD5/COD ratio to 0.41 after 2 h of electrolysis, indicating that the EF process can be effectively coupled with a biological treatment. The combined bio-electro-Fenton (bio-EF) approach successfully achieved complete mineralization, offering a cost-effective and sustainable strategy for the removal of recalcitrant pharmaceutical pollutants from water.