Heterogeneous Fenton degradation of bisphenol A using Fe 3 O 4 @β-CD/rGO composite: Synergistic effect, principle and way of degradation.

In this study, a multi-component catalyst, β-cyclodextrin (β-CD) and reduced graphene oxide (rGO) co-modified Fe ₃ O ₄ , was fabricated via one-pot solvothermal method and used as a synergistic catalyzer for Bisphenol A (BPA) removal. The study found that catalytic reactions of BPA followed the pseudo-first-order kinetics model, and the correlation rate constants (k _obs ) were calculated. Compared with Fe ₃ O ₄ @β-CD (0.02173 min ^-1 ), Fe ₃ O ₄ /rGO (0.09735 min ^-1 ) and Fe ₃ O ₄ (0.01666 min ^-1 ), the composite (0.15733 min ^-1 ) exhibited stronger catalytic ability to remove BPA from aqueous solution under the same conditions, which were attributed to the synergistic enhancement effect among the components. The introduction of rGO in the composites was beneficial to the generation of •OH, and the role of β-CD might enhance the utilization of •OH. A possible three-element catalytic schematic diagram was described. The effects of pH, dosage of the catalyst, initial H ₂ O ₂ and NH ₂ OH concentrations on the removal efficiency were further investigated. The removal of BPA and TOC retained 78.2 ± 2.4% and 52.9 ± 2.5% after five cycles, indicating its excellent stability and reusability. Furthermore, a probable reaction pathway of BPA removal was suggested by analyzing the intermediate products. All results indicated that the composite had high and stable catalytic performance, which made it have potential application on the industrial treatment of wastewater.
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