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

Abstract

AbstractBACKGROUNDThe efficient and green technology of dye removal has been widely investigated. In this study, a bio‐electro‐Fenton system was used to degrade methyl orange (MO). For the system optimization, five experimental groups were detected, including pH (1–6), iron (Fe2+) concentration (3–15 mmol L−1), airflow rate (0–20 mL min−1), external voltages (0.2–1.0 V) and initial MO concentration (20–100 mg L−1).RESULTSOptimal conditions of pH 3, Fe2+ concentration 9 mmol L−1, air flowrate 12 mL min−1, external voltage of 0.6 V and MO concentration 60 mg L−1 were selected, resulting in a 92% efficiency. For the pathway investigation of MO degradation, under oxidization by ˙OH, demethylation, broken azo bonds and broken benzene ring structure were obtained. Intermediate products were predicted. For the system evaluation, energy consumption of 0.15–0.59 KWh was determined for 1 m3 MO wastewater. The total cost of degrading MO wastewater could decrease to US$470.0 m−3 by adjusting operational time.CONCLUSIONConsidering the Fe2+ regeneration and the low energy consumption, this bio‐electro‐Fenton system can be considered as one of the most environmentally‐friendly approaches for MO degradation; however, quantitative evaluation on sustainability needs to be further discussed via advanced assessment tools (such as life‐cycle assessment). © 2024 Society of Chemical Industry (SCI).