Degradation of methyl orange dye by Fenton oxidation process using hydrolyzed PAN fibers loaded with FeMOF as the heterogeneous catalyst

The efficient degradation of dye pollutants continues to pose a significant challenge in wastewater treatment, primarily due to constraints in degradation efficiency and complications in catalyst recovery. To address these issues, a novel catalyst has been synthesized utilizing polyacrylonitrile fibers as a support material, which were subsequently loaded with iron-based metal–organic framework through a solvothermal approach. This catalyst, when combined with hydrogen peroxide (H₂O₂), forms a heterogeneous Fenton catalytic system that promotes the degradation of methyl orange (MO) in wastewater. A thorough investigation was conducted to examine the catalytic degradation performance of dyes and the underlying reaction mechanisms. The catalyst demonstrates outstanding performance in dye degradation, achieving 95.7% removal of methyl orange under ambient conditions. Moreover, it retains over 80% degradation efficiency after four consecutive reaction cycles, highlighting its strong recyclability and minimal loss of catalytic activity. Radical quenching experiments and electron paramagnetic resonance analyses confirm that the primary reactive oxygen species involved are hydroxyl radicals (·OH) and superoxide anions (·O₂⁻). Furthermore, both Fe^II and Fe^III ions can be recycled and regenerated in-situ, thereby continuously catalyzing H₂O₂ to produce ·OH and ·O₂⁻, which facilitates the sustained mineralization of dye molecules, thus enabling high dye degradation.

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