Construction of a flow-through catalytic reactor employing O3–Fe/TiO2 for efficient catalytic ozonation disinfection†

An effective air disinfection approach is necessary to prevent the spread of airborne microbial pathogens to protect public safety. Ozone is considered as a broad-spectrum and economical disinfection agent worldwide, while the health risks of ozone limited its practical application. In this study, we designed a flow-through O₃–catalyst reactor disinfecting air by converting O₃ into reactive oxygen species (ROS). FeOOH supported on TiO₂ (Fe/TiO₂) was prepared as a catalyst and the optimized O₃–Fe/TiO₂ reactor exhibits remarkable disinfection efficiency with a logarithmic (log) order of 3.53 (−log₁₀ (C/C₀)), which is 22-fold as high as that of ozone alone (8.2 ppm ozone and 93% relative humidity). Moreover, the O₃–Fe/TiO₂ reactor also exhibited significant disinfection efficiency (99.5%) and good stability (80 hours) with an ozone outlet concentration below 0.03 ppm which is the standard value recommended by the World Health Organization air quality guidelines. The radical scavenging tests, electron paramagnetic resonance (EPR), and in situ Raman studies indicated the hydroxyl radical (·OH) dominated the catalytic ozonation disinfection. Furthermore, physicochemical characterization, EPR, and electrochemical measurements revealed that the well-dispersed FeOOH increases the density of surface hydroxyl groups from 0.9 mM g⁻¹ to 1.5 mM g⁻¹ and accelerates the electron transfer between ozone and the catalyst, which greatly improves the production of ·OH and promotes the irreversible inactivation of bacteria. This catalytic ozonation reactor is designed and paves a promising way for efficient bioaerosol disinfection in open space and workplace with human beings to protect public health and achieve continuous production.