Enhanced photocatalytic disinfection of P. expansum in cold storage using a TiO2/ACF film

Spores of Penicillium expansum are the most important airborne component of fungal contamination and are commonly present in the moist air in cold storage rooms where fruits and vegetables are stored. To improve the ability of activated carbon felt-supported titanium dioxide (TiO2/ACF) to remove spores of P. expansum from the atmosphere, measurements for the removal efficiency of the spores at a temperature of 3 °C ± 1 °C and relative humidity of 90% ± 3% had been made on photocatalytically-activated (PC) silver-doped TiO2/ACF prepared by ion sputtering in two different modes and photoelectrocatalytically-activated (PEC) TiO2/ACF films. The Weibull distribution model was used to define the degree of microbial inactivation attributable to the PC or PEC films. The key parameters of the PC or PEC affecting the disinfection efficiency in terms of the reliable life (tR value) of this model were studied. Both silver-doped TiO2/ACF and PEC on TiO2/ACF improved destruction of this airborne microbe. Silver deposited on the surface of the prepared ACF-supported TiO2 films (Ag/Ti = 0.012, atomic ratios) dramatically reduced tR value. With respect to the PEC, a model was established using response surface methodology to describe the relationship between the tR value and the key affecting parameters, including light intensity and bias voltage. The optimized parameters were found to be a light intensity of 2.3 mW·cm− 2 with a bias voltage of 66.7 V.