Application of TiO2 photocatalysis for air treatment: Patents’ overview

Abstract A review of patents on the application of titanium dioxide photocatalysis for air treatment is presented. A comparison between water treatment and air treatment reveals that the number of scientific publications dedicated to photocatalytic air treatment is significantly lower than the number of scientific manuscripts dedicated to photocatalytic water treatment, yet the situation is reversed upon comparing relevant patents. This indicates a growing interest in the implementation of photocatalysis for air treatment purposes, which surpasses that of water treatment. This manuscript analyzes the various patents in the area of air treatment, while differentiating between indoor air treatment and outdoor air treatment. Specific efforts were made to characterize the main challenges and achievements en-route for successful implementation, which were categorized according to mass transport, adsorption of contaminants, quantum efficiency, deactivation, and, no less important, the adherence and the long term stability of the photocatalyst.

[1]  D. Ollis,et al.  Photoassisted heterogeneous catalysis with optical fibers: I. Isolated single fiber , 1977 .

[2]  A. Fujishima,et al.  Electrochemical Photolysis of Water at a Semiconductor Electrode , 1972, Nature.

[3]  Pierre Pichat,et al.  State of the art and perspectives on materials and applications of photocatalysis over TiO2 , 2005 .

[4]  R. T. Brown,et al.  TiO2 Photocatalysis for Indoor Air Applications: Effects of Humidity and Trace Contaminant Levels on the Oxidation Rates of Formaldehyde, Toluene, and 1,3-Butadiene. , 1995, Environmental science & technology.

[5]  R. Noble,et al.  Products, Intermediates, Mass Balances, and Reaction Pathways for the Oxidation of Trichloroethylene in Air via Heterogeneous Photocatalysis. , 1994, Environmental science & technology.

[6]  A. E. Jacobsen.  Titanium Dioxide Pigments: Correlation between Photochemical Reactivity and Chalking. , 1949 .

[7]  Alberto Strini,et al.  Measurement of benzene, toluene, ethylbenzene and o-xylene gas phase photodegradation by titanium dioxide dispersed in cementitious materials using a mixed flow reactor , 2005 .

[8]  A. Bard,et al.  Heterogeneous Photocatalytic Preparation of Supported Catalysts. Photodeposition of Platinum on TiO2 Powder and Other Substrates , 1978 .

[9]  A. Mills,et al.  A web-based overview of semiconductor photochemistry-based current commercial applications , 2002 .

[10]  C. Goodeve,et al.  Photosensitisation by titanium dioxide , 1938 .

[11]  J. Falconer,et al.  Photocatalytic and thermal catalytic oxidation of acetaldehyde on Pt/TiO2 , 1998 .

[12]  D. Blake,et al.  Direct mass spectrometric studies of the destruction of hazardous wastes. 2. Gas-phase photocatalytic oxidation of trichloroethylene over titanium oxide: products and mechanisms , 1993 .