Fluorine and carbon codoped macroporous titania microspheres: Highly effective photocatalyst for the destruction of airborne styrene under visible light

Airborne styrene is a suspected human carcinogen commonly present in industries where resins are used. Traditional ways of abating this pollutant include the use of various adsorbents (activated carbon or zeolites) or thermal treatment. The earlier method is simply a temporary containment of the pollutant, requiring spent adsorbents to be regenerated frequently, while the latter is energy-intensive. Work involving the photodegradation of airborne styrene is limited in recorded literature. This study uses a well-characterized combined fluorine/carbon codoped macroporous-titania catalyst, capable of destroying airborne styrene using irradiation in the visible range. A fluidized-bed photoreactor, combined with high-flow rates relative to the minimum fluidization velocity (U _mf) of the catalysts, is utilized in the photooxidation process. The effects of varying relative humidity (RH, 0 or 20%) are investigated in using both UV (248nm) and visible (400-700nm) irradiation. It is found that RH levels of 20% promote the complete degradation of 300 ppmV airborne styrene under both types of irradiation. Reaction intermediates on the surface of the used catalysts are probed by high-performance liquid chromatography (HPLC).