Application of a hybrid system comprising carbon-doped TiO2 film and a ceramic media-packed biofilter for enhanced removal of gaseous styrene

It is difficult to efficiently remove gaseous styrene using a TiO2 film-coated photoreactor under UV light. Therefore, we used a hybrid system consisting of a carbon-doped TiO2 (C-TiO2) film and a media-packed biofilter in order to enhance the removal efficiency (RE) of gaseous styrene compared to that of a pure (undoped) TiO2 photoreactor. The C-TiO2 was synthesized by a sol-gel combustion method, and its absorption spectrum was stronger that of pure (undoped) TiO2 in the UV-vis range. The resultant RE of the C-TiO2 film was 113-200% higher than that of the pure TiO2 film. The initial RE of the photoreactor for input styrene concentrations of 630 mg m−3, 420 mg m−3, and 105 mg m−3 was 20.6%, 29.8%, and 40.0%, respectively. When the biofilter was added, the RE increased to 93.3%, 97.9%, and 99.0%, respectively. Thus, application of the hybrid system consisting of both a photoreactor coated with a C-TiO2 film and a biofilter is advantageous in terms of the removal efficiency of gaseous styrene.