Engineering a visible-light-driven heterostructure: synergistic catalysis of bimetallic MIL-88B(Fe/Co)@TiO2 for efficient BPA mineralization

The pervasive environmental presence of endocrine-disrupting bisphenol A (BPA) necessitates advanced remediation technologies. This study presents the rational design and synthesis of a novel bimetallic MIL-88B(Fe/Co)@TiO2 heterostructure as a highly efficient visible-light-driven photocatalyst for BPA degradation. Comprehensive characterization via XRD, SEM-EDX, FTIR, and BET confirmed the successful integration of TiO2 nanoparticles with the bimetallic MOF, forming a composite with a narrowed bandgap (2.13 eV) and enhanced visible-light absorption. Response Surface Methodology (RSM) based on a Central Composite Design (CCD) optimized key operational parameters, predicting and achieving a remarkable 95.3% degradation under optimal conditions (pH 4.4, catalyst dose 43 mg, [BPA] 78 mg L− 1, [H2O2] 3.20%). Kinetic studies revealed rapid degradation following a pseudo-first-order model with a rate constant of 0.050 min− 1 and a half-life of 13.86 min. Scavenger experiments elucidated a synergistic mechanism where hydroxyl radicals (·OH), generated via a combined photocatalytic and Fenton-like pathway, played the dominant role. The catalyst demonstrated satisfactory stability over four consecutive cycles. The composite’s engineered synergy resulted in a high degradation efficiency, rapid kinetics, and compelling reusability, demonstrating its high potential for practical wastewater treatment applications.