Degradation of rhodamine B by fenton-like system with Fe-Cu/HZSM-5 catalyst

Abstract

Background

Rhodamine B (RhB) poses a significant threat to aquatic ecosystems. While Fenton oxidation process is promising approach for RhB degradation, the conventional Fenton reaction has the narrow pH range and poor reusability. To overcome these, this study developed Fenton-like system with Fe-Cu/HZSM-5 catalyst for effective RhB degradation.

Methods

A series of Fe_xCu_5-x/HZSM-5 catalysts (x represents the molar ratio of Fe to Cu) were prepared by impregnation. These catalysts were integrated with H₂O₂ to construct Fenton-like system for the degradation of RhB. The catalysts were characterized by XRD, NH₃-TPD, XPS, FT-IR, and N₂ adsorption-desorption at low temperature techniques.

Significant findings

Among the tested catalysts, Fe₃Cu₂/HZSM-5 exhibited optimal performance, achieving near-complete RhB degradation (∼100%) under the condition of 45 °C, 5.3 mM/L H₂O₂, 3.0 g/L catalyst dosage, and broad pH range (2–5). Mechanistic studies confirmed that hydroxyl radicals (·OH) were the primary oxidants responsible for RhB degradation in Fenton-like system. Under ·OH attacking, RhB underwent a series of reactions such as N-deethylation and disruption of the conjugated structure and was eventually mineralized into CO₂ and H₂O. Overall, a novel Fe-Cu/HZSM-5 catalyst was developed to address the limitations of the traditional Fenton reaction, providing valuable insights for future research in this field.