Efficient degradation of methyl orange in wastewater via bio‐electro‐Fenton system: optimization, pathway investigation and process evaluation
Wen Wang, Qiannan Wang, Yuying Peng, Vagelis G. Papadakis, Maria A. Goula, Xiaoyue Li, Tianze Xie, Ziyi Yang
Abstract
Abstract BACKGROUND The 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 (Fe 2+ ) 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 ). RESULTS Optimal conditions of pH 3, Fe 2+ 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 m 3 MO wastewater. The total cost of degrading MO wastewater could decrease to US$470.0 m −3 by adjusting operational time. CONCLUSION Considering the Fe 2+ 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).