Photocatalytic inactivation of viral particles of human norovirus by Cu-doped TiO2 non-woven fabric under UVA-LED wavelengths.

Metal-doped TiO2 photocatalysis are recognized as effective materials for eliminating human norovirus (HuNoVs). In recent years, the airborne transmission of viral particles of HuNoVs has been a cause for concern. In this study, we evaluated the virucidal effects of a Cu/TiO2 non-woven fabric (NWF) on viral particles of HuNoV genogroup II genotype 4 (HuNoV GII.4) under an ultraviolet A light-emitting diode (UVA-LED) source. For the optimized parameters, a multivariate statistical analysis using the Box-Behnken design (BBD) technique combined with the response surface methodology (RSM) was applied. The experimental results showed that the Cu/TiO2-based NWF degraded HuNoV viral particles in the air samples. The BBD-based RSM indicated that the optimum treatment conditions for inactivating the HuNoV GII.4 droplets with the Cu/TiO2 NWF were a 1:7.7 ratio of Cu:TiO2 and the use of a 373-nm UVA-LED source for 48.08 min. The optimal conditions for the photocatalytic efficacy in HuNoV GII.4 of Cu/TiO2 NWF were verified experimentally, giving a value of 2.89 ± 0.11 log10 genomic copies, which was the same as the predicted value (2.91611) within experimental uncertainty. This result adequately validated the predicted model and confirmed that viral particles of HuNoVs could efficiently be disinfected using Cu/TiO2 NWF stimulated by UVA-LED light.