Enhancing methyl orange discoloration with TiO₂/Fe₂O₃/AC composites: synergistic adsorption-photocatalysis

Fe 2 O 3 /TiO 2 /AC nanocomposites were successfully synthesized via a sol–gel method, and their efficacy in decomposing methyl orange via adsorption-photocatalytic processes was reported for the first time in this study. Systematic exploration of the physicochemical properties impacting photocatalytic activity was conducted through x-ray diffraction, scanning electron microscopy—energy-dispersive x-ray spectroscopy, and Fourier transform infrared spectroscopy (FTIR) characterizations. The study revealed that the discoloration of methyl orange resulted from a synergistic interplay between adsorption and photocatalysis. The incorporation of Fe 2 O 3 nanoparticles significantly elevated photocatalytic activity by 70%, with additional enhancement observed upon the introduction of activated carbon (AC) particles. The synergistic effects of AC adsorption and TiO 2 /Fe 2 O 3 photocatalysis exhibited remarkable efficiency in degrading methyl orange under visible light irradiation. The trial functioning of Fe 2 O 3 and AC in the TiO 2 /Fe 2 O 3 /AC composite, which serves as an adsorbent, an electron trap, and a co-catalyst providing active sites, significantly improved photocatalytic activity. These findings not only contribute to understanding the crucial role of composite TiO 2 in conjunction with metal and carbon-based co-catalysts but also hold valuable implications for advancing research in the development of adsorption-photocatalytic systems for wastewater treatment.