Synergistic effect of PANI and Cu-doped Fe-based MOF for effective photocatalytic degradation of antibiotic and dyestuff

As modern industry continues to develop rapidly, water pollution caused by antibiotics and synthetic dyes has become increasingly severe. To address the challenge of efficient treatment of such organic wastewater, a novel modified MIL-101(Fe) photocatalyst was constructed via a synergistic strategy of Cu²⁺ doping and in-situ polymerization of aniline. Under simulated solar irradiation, the composite photocatalyst achieved degradation efficiencies of 93.06% for tetracycline and 94.2% for methylene blue, exhibiting broad-spectrum photocatalytic activity toward various organic dyes. Cu²⁺ and PANI synergistically optimize the band structure, narrowing the bandgap to 2.23 eV while broadening the visible-light response range, promoting charge transport, and forming a stable Z-scheme heterojunction at the interface to suppress the recombination of photogenerated charge carriers. The results of reactive species trapping experiments showed that ·OH, h⁺, and ·O 2 - collectively governed the degradation process. The core mechanism stems from the ligand-to-metal charge transfer (LMCT) characteristics of MIL-101(Fe), the electron-trapping effect of Cu²⁺, and the conjugated conductive network of PANI. In addition, the composite photocatalyst exhibited strong resistance to ionic interference and maintained degradation efficiencies above 80% after five consecutive cycles, demonstrating excellent stability and reusability. This work provides an efficient photocatalytic material and a promising strategy for the comprehensive treatment of organic wastewater.