The enhanced visible-light-driven antibacterial performances of PTCDI-PANI(Fe(III)-doped) heterostructure

The development of visible-light-responsive photocatalysts with organic semiconductors is considered as an important and promising way to solve the energy crisis and environmental pollution. In this work, PTCDI and PTCDI-PANI(Fe(III)-doped) heterostructure were prepared through radical polymerization and modified amidation reaction. They could be used as visible-light-driven photocatalysts for the treatment of medical wastewater containing Staphylococcus aureus and E. coli bacteria. The as-prepared PTCDI-PANI(Fe(III)-doped) exhibited comparably higher photocatalytic activity beyond PTCDI. Under the irradiation of visible light, the PTCDI-PANI(Fe(III)-doped) showed optimized sterilization efficiencies towards E. coli and Staphylococcus aureus bacteria, which was 95.8% and 99.3%, respectively. The enhanced photo-induced antibacterial effect by PANI(Fe(III)-doped)-grafting was mainly attributed to: (1) PANI has a narrow band gap of 2.8 eV; (2) The relatively higher conduction band position (-2.1 eV) of PANI promotes the reaction of O₂+e^－⟶·OH; (3) The strengthened junctions of amide bond between PTCDI and PANI improve the separation efficiency of photogenerated electron-hole pairs; (4) The relatively rougher surface of PTCDI-PANI comparing with PTCDI improves the bio-surface interactions or bacterial adhesion; (5) Fe(III)-doping acts as a conducting tunnel and promotes the charge transfer between PANI and PTCDI.