Impact of Magnetic Field on ROS Generation in Cu-g-C3N4 Against E. coli Disinfection Process

The antibacterial activity of g-C3N4 and Cu-g-C3N4 was evaluated against E. coli, with their disinfection capabilities influenced by structural characteristics, photocatalytic properties, and modulation under a static magnetic field. The incorporation of Cu2+ does not significantly affect the (210) reflection in XRD analysis, indicating that the alignment of aromatic layers remains stable. However, the presence of copper enables complete disinfection, in contrast to graphitic carbon nitride, which achieves only partial disinfection. Cu2+ is likely positioned at N-aliphatic sites and coexists with hydroxylated species, which may influence photocatalytic performance by modifying reactant adsorption and ROS generation. SEM-EDS analysis confirmed that Cu2+ modification did not significantly alter the material’s morphology, although a 3% copper content was detected, suggesting a heterogeneous surface distribution. Thermodynamic analysis showed that exposure to a magnetic field increased the Gibbs free energy of adsorption from 6.34 J/m2 to 10.52 J/m2, reducing interactions with key reactants essential for ROS formation. As a result, both disinfection and photodegradation efficiency were significantly diminished. Additionally, the presence of a magnetic field was found to modify the surface properties of the material, affecting its photocatalytic performance. In Cu-C3N4 materials, a decrease in the contact angle suggests enhanced hydrophilicity, while an increase in surface tension may influence the adsorption of water and hydroxyl radicals. This study underscores the effect of a magnetic field on the photocatalytic behavior of materials deposited on polymeric substrates with intrinsic electronic properties, ultimately impacting overall disinfection efficiency.