Adsorption-enhanced photocatalytic waterborne virus inactivation by graphite carbon nitride conjugated with covalent organic frameworks

Abstract

The increasing outbreaks of virus-related diseases drive the need to inactivate waterborne viruses efficiently and eco-friendly. Here, g-C3N4@COF heterojunction photocatalysts were synthesized for adsorption-enhanced photocatalytic inactivation of viral surrogates (phage MS2). The modified g-C3N4 outperformed g-C3N4 nanosheets in charge-carrier separation and quantum yield (with photocurrent intensity of 0.15 vs 0.02 μA and fluorescence lifetime of 11.6 vs 1.7 ns). COF exhibited a larger specific surface area (90.883 vs 20.801 m2/g) and less negative-charged surface (−13.8 vs −30.1 mV) than g-C3N4. Accordingly, modified g-C3N4 facilitated virus adsorption and improved the reactive species utilization efficiency, resulting in 7.36 times more efficient virus inactivation relative to g-C3N4. For g-C3N4@COF, the predominant reactive species causing virus inactivation through capsid destruction and genome degradation were superoxide radicals (•O2−) and photogenerated holes (h+). Interestingly, our study found the efficiency trade-offs that the appropriate adsorption of phage MS2 enhanced photocatalytic inactivation but over-adsorption affected the inactivation rate negatively. Overall, our study demonstrates that g-C3N4@COF heterojunction photocatalyst can simultaneously improve reactive species (RS) generation and utilization, which enhances the photocatalytic inactivation of waterborne viruses.