Facile Synthesis of MIL-53(Fe) and its Modification with Green-Synthesized TiO₂ for Enhanced Photocatalytic Degradation of Methylene Blue

Abstract

The continuous release of dye-laden wastewater from industrial processes has become a major environmental and public health concern, highlighting the need for effective and environmentally friendly treatment technologies. In this work, MIL-53(Fe) was synthesized using a solvothermal approach, whereas TiO₂ nanoparticles were produced through a green synthesis method employing Jatropha curcas leaf extract as both a reducing and stabilizing agent. TiO₂–MIL-53(Fe) nanocomposites, denoted as TM-10 and TM-30, were subsequently prepared and investigated for the visible-light-assisted photocatalytic degradation of methylene blue (MB). The structural, morphological, and optical properties of the synthesized materials were examined using FTIR, XRD, SEM, and UV–Vis spectroscopy. The characterization results verified the successful integration of TiO₂ into the MIL-53(Fe) framework, leading to enhanced crystallinity, improved surface morphology, and superior optical performance. The effect of operation parameters on the degradation was also studied. Results showed that the removal rate of methylene blue increased with the increased dosage of catalyst and decreased initial concentration of methylene blue and the acidic condition is favorable for degradation. In particular, TM-30 exhibited a narrowed band gap of 1.8 eV, indicating greater responsiveness to visible-light irradiation. Photocatalytic experiments showed that methylene blue degradation increased progressively with irradiation time for all catalysts, with the activity following the sequence TM-30> TM-10 > TiO₂ > MIL-53(Fe). Under visible-light irradiation for 180 min, TM-30 achieved a degradation efficiency of 90%, markedly exceeding that of the individual components. The superior photocatalytic performance was attributed to enhanced charge-carrier separation, reduced electron–hole recombination, and the synergistic interaction between TiO₂ and MIL-53(Fe). These results highlight the promise of the green-synthesized TM-30 composite as a highly efficient and sustainable photocatalyst for dye-contaminated wastewater treatment.