Synthesis of the MnO₂-Fe₃O₄ catalyst support on amorphous silica: a new Fenton’s reagent in the degradation of the reactive blue-19 in aqueous solution

Abstract

In this study, a new Fenton’s reagent was synthesized via two steps: (1) the dispersed Fe₃O₄ nanoparticles were immobilized on the surface of the SiO₂ carrier via the precipitation process, and (2) the MnO₂ nano-sheets were coated on the surface of Fe₃O₄/SiO₂ via hydrothermal method. The SiO₂ carrier has been synthetically utilized from Vietnamese rice husk. The successful formation of the MnO₂-Fe₃O₄/SiO₂ composite has been analytically characterized by the XRD (X-ray diffraction), SEM (scanning electron microscope), EDS (energy dispersive spectrometry)-mapping, FTIR (Fourier transform infrared), S_BET (Brunauer-Emmett-Teller specific surface area), and adsorption/desorption isotherms. This Fenton system was employed to catalyze degradation process of the reactive-blue 19 (RB19) with approximately 100% of removal efficiency after 25 min at the optimal condition of 0.15 g/100 mL of catalyst dosage, pH = 3, and the H₂O₂ concentration of 3 mL/100 mL. Moreover, the catalyst could be reused at least six times with high catalytic activity that was more than 90%. In conclusion, this study showed that the mesoporous MnO₂-Fe₃O₄/SiO₂ composite has a great potential for the removal application of dyes from wastewater, and the application of Vietnam rice husk in environmental treatment was developed.

Keywords:

• Fe₃O₄-MnO₂ composite
• rice husk
• hydro peroxide
• absorption
• removal efficiency
• reactive blue-19

Authors’ contributions

NMH Conceptualization, investigation, and formal analysis, TTH: Writing-original draft, NTS: Writing-review and editing.

Disclosure statement

The authors declare that they have no conflict of interests.

Additional information

Funding

The author(s) reported there is no funding associated with the work featured in this article.