Degradation of Metoprolol by photo-Fenton: Comparison of different photoreactors performance

Abstract

The degradation of Metoprolol (MET) by photo-Fenton was studied in different photoreactors. The importance of the irradiation source, UVC (λ=254nm), black blue lamps (λ=365nm) and simulated sunlight, was investigated at lab-scale experiments. Moreover, compound parabolic collectors (CPC), at pilot-scale with sunlight, have been also applied. Photo-Fenton treatment employing black blue lamps gave the best results, in terms of mg MET removal per accumulated energy. Using the highest Fe2+ (10mg/L) and H2O2 (150mg/L) concentrations, the best results of MET degradation and mineralization were obtained for BLB: 100% of MET elimination (0.41kJ/L, 7min) and 81.2% of TOC conversion (5.30kJ/L, 90min). Using solarbox (SB) 97.3% of MET elimination (1.50kJ/L, 7min) and 78.8% of TOC conversion (25.8kJ/L, 120min) were reached. With UVC 100% of MET elimination (4.8kJ/L, 20min) and 17.6% of TOC conversion (14.4kJ/L, 60min) were obtained. Finally, in CPC, 100% of MET elimination (0.67kJ/L, 3min) and 83.7% of TOC conversion (33.9kJ/L, 150min) were achieved. A general pathway of Metoprolol degradation by photo-Fenton process is proposed according to the intermediates detected. Regarding to toxicity, all processes have promoted the overall toxicity reduction of MET solution. Operating costs for the different experiments were also estimated and compared.