Removal of microbial aerosol using titania/chitosan composites in air conditioning systems

The humid environment of the air conditioning system promotes the growth of microorganisms on the filter media. Using filter media with antibacterial properties can solve this problem. As a photocatalytic material, TiO2 is often added to certain products as an antimicrobial. Chitosan (CS) is an antibacterial substance that can be processed into fibers, so it can be considered as a substitute for polypropylene (PP) fiber, which is currently commonly used as a filter medium. Unlike previous studies, this study used an air duct experiment system to simulate the operating conditions of air conditioning systems, and TiO2 was supported by CS and PP fiber, respectively. Results show that TiO2/CS exhibited better filtration and antibacterial properties at a 3% TiO2 impregnation concentration. When the basic weight of CS is 190 g/m2, the filtration efficiency can reach 96.8% with only 6 W ultraviolet, but the pressure drop is only 28 Pa. At the same time, the survival of bacteria on CS filter media is about 60% lower than that on PP and bacterial shedding is decreased by more than 35%. Due to the excellent filtration and antibacterial properties of TiO2/CS composite, its use in air conditioning systems will be of interest.