Efficient degradation of methyl orange in wastewater via bio‐electro‐Fenton system: optimization, pathway investigation and process evaluation

Abstract

BackgroundThe efficient and green technology of dye removal has been widely investigated. In this study, bio‐electro‐Fenton system was used to degrade methyl orange (MO). For the system optimization, five experimental groups were detected, including pH (1–6), Fe2+ concentration (3–15 mM), airflow rate (0–20 mL/min), external voltages (0.2–1.0 V), and initial MO concentration (20–100 mg/L).ResultspH 3, Fe2+ concentration of 9 mM, air flowrate of 12 mL/min, external voltage of 0.6 V and MO concentration of 60 mg/L were selected as the optimal conditions, resulting in the efficiency of 92%. For the pathway investigation of MO degradation, under the oxidization by •OH, demethylation, azo bond broken and benzene ring structure broken were obtained. Intermediate products were predicted. For the system evaluation, energy consumption of 1 m3 MO wastewater was 0.15–0.59 KWh. The total cost of degrading MO wastewater could decrease to 470.0 $/m3 by adjusting operational time.ConclusionConsidering the Fe2+ regeneration and the little energy consumption, the bio‐electro‐Fenton system could be considered as one of the most environment‐friendly approaches for MO degradation, while, quantitative evaluation on sustainability needed to be further discussed via advanced assessment tools (such as life cycle assessment).This article is protected by copyright. All rights reserved.