The high efficiency particulate air filter is used widely to remove particulates and microorganisms from the air stream. However, the filter may become a source of microbes if those retained microorganisms proliferate and re-entrain back into the filtered air. This study demonstrates that such a problem can be handled effectively by using photocatalytic reactions to inactivate those confined microorganisms. A 60-100% microbe reduction can be achieved for a wide variety of microorganisms to provide better indoor air quality for hospitals, offices, and domestic applications.

Non-decomposable plastic has been replaced with polylactic acid, which is a biodegradable aliphatic polyester stationary phase, in composite films embedded with a TiO 2 photocatalyst for mitigation of indoor air pollution. PLA has superior properties relative to those of other biopolymers, such as a relatively high melting point, crystallinity, and rigidity. This study aimed to incorporate TiO 2 -anatase into PLA for use as a photocatalyst using the blown film method. Photocatalytic oxidation, an advanced oxidative process, has been recognized as an economical technique providing convenience and efficiency with indoor air treatment. Therefore, the use of new environmentally friendly biodegradable polymers provides an alternative way to address the severe environmental concerns caused by non-decomposable plastics. UV–vis spectrophotometry and scanning electron microscopy–energy-dispersive X-ray spectroscopy (SEM–EDX) were used to observe the dispersibility and mixing capacity of the TiO 2 -anatase PLA matrix. TiO 2 dosages were 5, 10, and 15% (wt/wt), and they were incorporated with a twin-screw extruder. SEM–EDX images demonstrated the homogeneity of TiO 2 distribution in the PLA matrix. The energy band gaps of TiO 2 in the PLA/TiO 2 -composite films were between 3.14 and 3.22 eV. The relationship between the photocatalytic oxidation rate and the TiO 2 dosage in the PLA/TiO 2 -composite films was determined. A prototype reactor model is geared toward the development of air purifiers for indoor air conditioning. Rate constants for benzene degradation were obtained using first-order kinetics to find rate constants matching experimental findings. In the PLA/TiO 2 -composite film, the TiO 2 -anatase photocatalyst was able to degrade 5 ppm benzene. This work contributes to the use of ecoefficient photocatalytic oxidation.