Heterogeneous Photocatalysis as an Advanced Oxidation Process for the Abatement of Chlorinated, Monocyclic Aromatic and Sulfurous Volatile Organic Compounds in Air: State of the Art

This review focuses on both fundamentals and applicability of heterogeneous photocatalysis as an advanced oxidation technology for degradation of volatile organic compounds (VOC) in air, with peer-reviewed literature data published since 1997 being the backbone of this article. Four key issues are covered. First, the underlying principles of heterogeneous photocatalysis are outlined using the band gap model. Second, a detailed overview is given of chlorinated, monocyclic aromatic and sulfurous VOC recently selected as target compounds in lab-scale photocatalytic degradation experiments. Data on reactor types, photocatalysts, reaction conditions, and reported results are tabulated. The third section deals with reaction products, analytical techniques used for separation and/or identification, proposed reaction pathways, and catalyst deactivation. Finally, effects of process parameters such as gas-phase pollutant and oxygen concentration, relative humidity, temperature, and light intensity on degradation kinetics are reviewed.