A photocatalytic water disinfection approach is under development by researchers from Yangzhou University The edges of the sheets are loaded with carboxyl and carbonyl molecules to attract additional electrons. Source: Teng and Yang et aland Chinese Academy of Sciences as an efficient and environmentally sound way to rid potable supplies of harmful bacteria. The technology is viewed as an attractive alternative to current water filtration systems based on chlorination or ozone disinfection, which may produce secondary pollutant species.

Nanosheets of graphitic carbon nitride serve as the catalytic component, as these generate more of the reactive oxygen species required to deactivate pathogens relative to the widely studied carbon nanotube and graphene oxide options. Thin sheets of the 2D material were demonstrated to destroy 99.99% of Escherichia coli bacteria in a 50 ml sample in just 30 minutes of visible-light irradiation.

The disinfection efficiency of the material is attributed to its structure -- the researchers loaded the edges of the sheets with carboxyl and carbonyl molecules, which drew additional electrons to these edges. The graphitic carbon nitride showed a first-order disinfection rate that is five times higher than the previously reported best metal-free photocatalyst, and the disinfection reaction consumes only one-tenth of the catalyst. The catalytic activity was also observed to be comparable to that of the best metal-based photocatalyst.

Technology refinement efforts will next seek to improve process efficiency by expanding the edge of the material's ability to absorb photons, developing antibacterial fibers and refining the nanosheet preparation process.