Photocatalytic Performance of Zinc Ferrite Magnetic Nanostructures for Efficient Eriochrome Black-T Degradation from the Aqueous Environment under Unfiltered Sunlight

Herein, three different types of zinc ferrite (ZnFe₂O₄) magnetic nanoparticles as photocatalysts were synthesized from iron and zinc sulfate using a co-precipitation method. Tri ethylene glycol (TEG) was utilized as a capping/stabilizing agent in the presence of ammonium hydroxide. The as-prepared nanoparticles were annealed at 400 °C for 4 h followed by acid etching with HCl (for 15 min in I M solution). The thermally treated magnetic nanostructure was subjected to surface modification by treating with 3-aminopropyl (triethoxysilane) 3-(APTES) at 60 °C for 2 h. Various characterization techniques including Fourier transform infrared (FTIR), Brunauer-Emmett-Teller (BET), and X-rays diffraction (XRD) were carried out to examine the structural properties of the pristine and functionalized nanocrystals. XRD pattern assessed the crystalline and nano size of the ZnFe₂O₄ recording particle sizes of 13.5, 23.3, and 106.5 nm for functionalized, annealed, and pristine ZnFe₂O₄ nanoparticles, respectively. FTIR spectral analysis corroborated the modifications and functionalization of the samples. BET analysis revealed a surface area of 0.6719 (functionalized), 45.21 (annealed), and 155.38 (pristine nanoparticles). The photocatalytic activity of the prepared nanostructures was investigated for Eriochrome Black T (EBT) dye under the unfiltered sunlight. At optimal reaction parameters, the photocatalytic rates of EBT dye for functionalized, annealed, and blank NP’s were 92, 91, and 83%, respectively. Kinetic models demonstrate that the degradation processes followed pseudo-first-order kinetics. The energies of the band gap in the acidic and basic media, as determined from the Tauc plot, were 2.47 and 2.7 eV, respectively. Taken together, the results showed that newly fabricated nanostructures are considered as promising photocatalysts in degrading organic pollutants for a sustainable environment.