Evaluation of the effectiveness of Fenton and photo-Fenton processes for degradation and mineralisation of the model pollutant caffeine

This study investigates caffeine degradation and mineralisation using Fenton and photo-Fenton processes through a 2k Factorial Design. Key parameters varied include Fe2+ concentration (2 and 10 mg/L), H₂O₂ concentration (50 and 500 mg/L), light intensity (0 and 96 W), and reaction time (0 and 60 min) to optimise degradation. The experimental setup featured a 1 L glass contact column in a UV-controlled chamber with an initial caffeine concentration of 20 mg/L. Results revealed that Fenton was inefficient, achieving only 12% degradation and 9% mineralisation, with dimethylparabanic acid as the main by-product. Conversely, photo-Fenton attained 88% degradation and 40% mineralisation, demonstrating the significant influence of UV light. Energy consumption varied from 3.33 to 50 kWh.m−3. Optimal conditions identified were 10 mg/L Fe2+, 50 mg/L H₂O₂, 96 W UV intensity, and a 60-minute reaction time, highlighting the effectiveness of advanced photo-Fenton oxidation for caffeine treatment. © 2024 Informa UK Limited, trading as Taylor & Francis Group.