Photocatalytic Composite Nanomaterial and Engineering Solution for Inactivation of Airborne Bacteria

In this study we propose a new composite material with an enhanced bactericidal action that utilises the complex interactions with bacteria: mechanical interactions of the bacteria with ZnO tetrapod spikes, a photocatalytic process on ZnO nanoparticles, and disinfection by Ag nanoparticles. ZnO and Ag nanoparticles were immobilised on a single-crystalline ZnO tetrapod by the ultrasonic mixing method. The XRD, TEM, SEM and EDS analyses showed the tetrapod-like crystals covered by ZnO and Ag nanoparticles. This complex photocatalytic material, deposited on a grid support, was tested in the UV purifier air system in the AR Diagnostic company. The active microbial monitoring of the indoor air showed a decrease in the concentration of bacteria in the air of the meeting room, with the door open, at 90% for a duration of 30–40 min. A simple variant of the design of an air purifier system, which can be mounted in different types of air channels and compartments, is proposed.