Sol-gel auto combustion synthesis, characterization, and application of TbFeMnO nanostructures as an effective photocatalyst for the discoloration of organic dye contaminants in wastewater.

In this study, the auto-combustion sol-gel method was used to prepare novel TbFeMnO (TFMO) double perovskite nanoparticles. Chemical and natural fuels were used to achieve these particles with appropriate size. The resulting particles were examined X-ray powder diffraction (XRD) and scanning electron microscopy (SEM) techniques. Rietveld analysis was also performed to confirm the crystallinity and lattice parameters of the formed particles. The particles obtained in the presence of maleic acid were selected as the optimal sample (S4), and the particles obtained in the presence of pomegranate paste were chosen as the non-optimal sample (S8) in terms of size and morphology. Both particles were used to investigate the photocatalytic activity. Fourier transform infrared spectroscopy (FTIR), UV-Vis diffuse reflectance spectroscopy (DRS), and vibrating sample magnetometer (VSM) analyses and N adsorption/desorption isotherms were performed for both samples and the results were compared. Erythrosine and malachite green dyes in aqueous solutions were used as contaminants in the photocatalysis process. The results showed 22% and 20% discoloration for S4 and 41% and 30% discoloration for S8 in the presence of erythrosine and malachite green under visible light irradiation. The photocatalytic activity was investigated under UV light for S4, which showed 80% and 50% discoloration for erythrosine and malachite green, respectively. Investigating the photocatalytic activity of TFMO double perovskite nanoparticles showed that these nanoparticles could be a desirable option for mitigating water pollution.