Fabrication of Water-Based TiO2-Coated Pleated Synthetic Fiber toward Photocatalytic Oxidation of VOCs and CO for Indoor Air Quality Improvement

Abstract

While titanium dioxide (TiO2) is highly regarded as one of the most promising catalysts for air-pollution mitigation, its practical use has been challenging due to structural complexity, process scalability, and high cost of existing fabrication methods. In this study, a facile spray-coating method is employed for fabrication of a TiO2-coated filter, with fibrous structure allowing for satisfactory airflow, sufficient pollutant–catalyst interactions, and reusability. Scanning electron microscopy (SEM) analysis shows that TiO2 nanoparticles were immobilized firmly on the surface of the membrane’s fibers. Energy dispersive X-ray (EDX) analysis reveals a homogeneous layer of TiO2 nanoparticles on the pleated washable synthetic (PWS) fibers. The photocatalytic oxidations of volatile organic compounds (VOCs) and carbon monoxide (CO) are analyzed in both the laboratory and field tests. TiO2-coated PWS filter membrane (60×60×5 cm) shows higher benzene and toluene removal efficiency (approximately 80%–86%) under UV radiation than that in the dark (less than 10%). This result indicates that photocatalytic oxidation on the surface of TiO2-coated PWS filter membrane contributes greatly to benzene and toluene degradation. The corresponding pilot-scale photocatalytic air filtration unit shows ethylene reduction rate of 1.59±0.52 ppm min−1 in a 45 m3 postharvest storage room. In a demonstrative elimination of automotive exhaust gases, the TiO2 coated PWS filter membrane shows a 16% decrease in CO generated from a motorcycle. This study shows the potential use of the cost-effective TiO2-coated filter membrane for indoor air quality improvement.