Enhanced photocatalytic activity of Fe₃O₄-WO₃-APTES for azo dye removal from aqueous solutions in the presence of visible irradiation

ABSTRACT

Development of highly active photocatalysts for treatment of dye-laden wastewaters is vital. The photocatalytic removal of azo dye Reactive Black 5 was investigated by Fe₃O₄-WO₃-3-aminopropyltriethoxysilane (APTES) nanoparticles in the presence of visible light. The Fe₃O₄-WO₃-APTES nanoparticles were synthesized via a facile coprecipitation method. The photocatalyst was characterized by XRD, FT-IR, SEM, EDX, VSM, UV–Vis, and pH_PZC techniques. The effects of some operational parameters such as solution pH, nanophotocatalyst dosage, initial RB5 concentration, H₂O₂ concentration, different purging gases, and type of organic compounds on the removal efficiency were studied by the Fe₃O₄-WO₃-APTES nanoparticles as a photocatalyst. Maximum phtocatalytic activity was obtained at pH 3. The photocatalytic removal of RB5 increased with increasing H₂O₂ concentration up to 5 mM. The removal efficiency declined in the presence of different purging gases and all types of organic compounds. First-order rate constant (k_obs) decreased from 0.027 to 0.0022 min⁻¹ and electrical energy per order (E_Eo) increased from 21.33 to 261.82 (kWh/m³) with increasing RB5 concentration from 10 to 100 mg/L, respectively. The efficiency of LED/Fe₃O₄-WO₃-APTES process for RB5 removal was approximately 89.9%, which was more effective than the LED/Fe₃O₄-WO₃ process (60.72%). Also, photocatalytic activity decreased after five successive cycles.

KEYWORDS:

• Fe₃O₄-WO₃-APTES
• kinetic models
• photocatalysis
• reactive black 5 removal
• visible light

Acknowledgment and funding

This paper is issued from an integrated research of 1290413798 as a thesis number MS student thesis of Kobra Ayagh. Financial support was provided by Guilan University of Medical Sciences, Rasht, Iran.