Efficient degradation of methylene blue at near neutral pH based on heterogeneous Fenton-like system catalyzed by Fe2O3/MnO2
Tie Geng, Jiaguo Yan, Bin Li, Haiyuan Yan, Lei Guo, Qiang Sun, Zengfu Guan, Chunning Zhao, Jinchao Xu, Weichao Wang
Abstract
• The Fe 2 O 3 /MnO 2 heterogeneous Fenton catalyst was fabricated and characterized. • The suggested Fenton-like system could degrade 100 % of methylene blue in 10 min. • Fe 2 O 3 /MnO 2 exhibits outstanding catalytic activity within a broad pH range. The contamination of aquatic environments by organic dye contaminants in industrial wastewater has attracted widespread global attention. The heterogeneous Fenton-like process presents an attractive method for degrading dye pollutants, especially when such reactions are conducted under neutral pH. In this study, Fe 2 O 3 /MnO 2 composite was employed as a novel heterogeneous catalyst for activating hydrogen peroxide (H 2 O 2 ) to oxidize and subsequently degrade methylene blue (MB) under neutral pH. Multiple characterization results have confirmed the presence of MnO 2 and Fe 2 O 3 as the primary phases of the synthesized compound catalyst. Degradation experiments have demonstrated that the degradation efficiency of MB approaches 100% under the conditions of H 2 O 2 concentration of 0.30% and Fe 2 O 3 /MnO 2 amount of 0.888 g/L. Furthermore, the Fe 2 O 3 /MnO 2 catalyst exhibits consistent and outstanding catalytic activity within a broad pH range from 5 to 9 benefiting from the strong interface interaction in Fe 2 O 3 /MnO 2 . The investigation into the kinetics of the Fenton-like reaction indicates that the catalytic degradation of MB by Fe 2 O 3 /MnO 2 in conjunction with H 2 O 2 follows pseudo-first-order kinetics. Moreover, supplementary scavenging experiments have demonstrated the crucial role played by hydroxyl radicals (·OH) in the catalytic oxidation mechanism of MB. This study offers a promising catalyst for the treatment of dye-containing wastewater under neutral pH condition.