Graphitic carbon nitride (C3N4) has gained broad attention as a metal-free photocatalyst for water disinfection. However, the low photocatalytic bactericidal activity of pristine C3N4 limits its applications. Here, we report a facile method to boost the photocatalytic disinfection activity of C3N4 with polyethyleneimine (PEI). With PEI modification, the generation of long-lifespan reactive oxygen species (ROS,•O2− and H2O2) in photocatalysis is significantly improved. Additionally, scanning electron microscopy and the atomic force microscopy force spectroscopy characterization reveal that PEI promotes the bacteria-photocatalyst contact via electrostatic adhesion. Due to the synergistic modulation of ROS generation and bacteria-photocatalyst interaction, the photocatalytic bactericidal activity of C3N4 is dramatically enhanced after PEI modification. Notably PEI/C3N4 composite achieves 6.2 logs of inactivation efficiency for Escherichia coli within 45 min and 4.2 logs for Enterococcus faecalis within 60 min under simulated solar irradiation. Overall, this work provides insights on designing metal-free photocatalysts with judicious polymer for antibacterial applications.
- Bacteria-photocatalyst interface
- Graphitic carbon nitride
- Metal-free photocatalyst
Peter Miller (Manager)Office of the Vice-Provost (Research and Research Infrastructure)
Sean Langelier (Manager)Office of the Vice-Provost (Research and Research Infrastructure)
Georg Ramm (Manager), Simon Andrew Crawford (Operator), Hariprasad Venugopal (Operator), Joan Marea Clark (Operator) & Gediminas Gervinskas (Operator)Faculty of Medicine Nursing and Health Sciences Research Platforms