Highly thermostable anatase titania-pillared clay for the photocatalytic degradation of airborne styrene

Airborne styrene is a suspected human carcinogen, and traditional ways of mitigation include the use of adsorption technologies (activated carbon orzeolites) orthermal destruction. These methods present their own shortcomings, i.e., adsorbents need to be regenerated or replaced regularly, and relatively large energy inputs are required in thermal treatment. Photocatalysis offers a potentially sustainable and clean means of controlling such fugitive emissions of styrene in air. The present study demonstrates a new type of well-characterized, highly thermostable titania-pillared clay photocatalysts for airborne styrene decomposition in a customdesigned fluidized-bed photoreactor. This photocatalytic system is found to be capable of destroying up to 87% of 300 ppmV airborne styrene in the presence of ultraviolet (UV) irradiation. The effects of relative humidity (RH: 0 or 20%) are also studied, together with the arising physical structures (in terms of porosity and surface characteristics) of the catalysts when subjected to relatively high calcination temperatures of 1000-1200°C. Such a temperature range may be encountered, e.g., in flue gas emissions (7). It is found that relative humidity levels of 20% retard the degradation efficiencies of airborne styrene when using highly porous catalysts.