One-Pot Phyto-Mediated Synthesis of Fe₂O₃/Fe₃O₄ Binary Mixed Nanocomposite Efficiently Applied in Wastewater Remediation by Photo-Fenton Reaction

A binary Fe₂O₃/Fe₃O₄ mixed nanocomposite was prepared by phyto-mediated avenue to be suited in the photo-Fenton photodegradation of methylene blue (MB) in the presence of H₂O₂. XRD and SEM analyses illustrated that Fe₂O₃ nanoparticles of average crystallite size 8.43 nm were successfully mixed with plate-like aggregates of Fe₃O₄ with a 15.1 nm average crystallite size. Moreover, SEM images showed a porous morphology for the binary Fe₂O₃/Fe₃O₄ mixed nanocomposite that is favorable for a photocatalyst. EDX and elemental mapping showed intense iron and oxygen peaks, confirming composite purity and symmetrical distribution. FTIR analysis displayed the distinct Fe-O assignments. Moreover, the isotherm of the developed nanocomposite showed slit-shaped pores in loose particulates within plate-like aggregates and a mesoporous pore-size distribution. Thermal gravimetric analysis (TGA) indicated the high thermal stability of the prepared Fe₂O₃/Fe₃O₄ binary nanocomposite. The optical properties illustrated a narrowing in the band gab (Eg = 2.92 eV) that enabled considerable absorption in the visible region of solar light. Suiting the developed binary Fe₂O₃/Fe₃O₄ nanocomposite in the photo-Fenton reaction along with H₂O₂ supplied higher productivity of active oxidizing species and accordingly a higher degradation efficacy of MB. The solar-driven photodegradation reactions were conducted and the estimated rate constants were 0.002, 0.0047, and 0.0143 min⁻¹ when using the Fe₂O₃/Fe₃O₄ nanocomposite, pure H₂O₂, and the Fe₂O₃/Fe₃O₄/H₂O₂ hybrid catalyst, respectively. Therefore, suiting the developed binary Fe₂O₃/Fe₃O₄ nanocomposite and H₂O₂ in photo-Fenton reaction supplied higher productivity of active oxidizing species and accordingly a higher degradation efficacy of MB. After being subjected to four photo-Fenton degradation cycles, the Fe₂O₃/Fe₃O₄ nanocomposite catalyst still functioned admirably. Further evaluation of Fe₂O₃/Fe₃O₄ nanocomposite in photocatalytic remediation of contaminated water using a mixture of MB and pyronine Y (PY) dyestuffs revealed substantial dye photodegradation efficiencies.