Effect of Inorganic Anions on Degradation Performance of Azo Dyes by Ultrasonically-Treated Fe81B10Si9 Metallic Glass

Abstract:

In recent years, industrial dye wastewater like azo dyes has caused severe environmental problems. Metallic glasses (MGs) are considered as promising catalysts for efficient water remediation due to their unique disordered structure, high Gibbs free energy, and excellent corrosion resistance. Ultrasonic pre-treatment was employed to enhance the catalytic performance of Fe₈₁B₁₀Si₉ MG. Results show that the sample treated with ultrasonic energy of 500 J exhibits the optimal reaction rate constant (k_obs) of 1.66 min^-1 compared with the untreated sample. The impact of typical anions (e.g., Cl^-, H₂PO₄^-, NO₂^-, and SO₄^2-) on the methylene blue solution degradation during the Fenton-like process (Fe-MG/H₂O₂) was investigated. With the increase in anion concentration, Cl^-, H₂PO₄?, and NO₂? all inhibit the degradation to varying degrees (k_obs< 0.2 min^-1), whereas SO₄^2- has a relatively weaker effect on the degradation process (k_obs=0.76 min^-1). Using Cl^- as a representative, the synergistic mechanism involved in the process was analyzed. Quenching experiment results indicate that ·OH are the dominant active species, which is synergistically regulated by solution chemistry and surface pathways. The ultrasonic-induced surface morphology reconstruction and valence state regulation enhance the catalytic stability in complex anionic environments. This work provides theoretical guidance for designing and developing high-performance MG catalysts in complex water environment.