Concrete containing TIO2: an overview of photocatalytic NOX abatement

Author(s): R. Amadelli and L. Samiolo
Paper category : conference
Book title: International RILEM Symposium on Photocatalysis, Environment and Construction Materials - TDP 2007
Editor(s): P. Baglioni and L. Casssar
Print-ISBN: 978-2-35158-056-1
e-ISBN: 978-2-35158-057-8
Publisher: RILEM Publications SARL
Publication year: 2007
Pages: 155 - 162
Total Pages: 8
Language: English

Abstract: Nitrogen oxides, NOx (NO + NO2), represent major air pollutants. They have a key role in the formation of ozone and, in general, of the so-called ‘photochemical smog’. A high level of nitrogen oxides in indoor environments is also a matter of particular concern.
Heterogeneous photocatalysis on TiO2 is a promising method for NOx abatement. From the applied point of view, a drawback of the use of pure TiO2 is that of surface saturation by adsorbed intermediates and/or products. This limited storage capability of TiO2 requires an adsorbent (such as cement) which is photochemically inert but plays a key role in determining the efficiency of the overall photocatalytic process. By comparison, adsorption of NO is less critical but as NO2 is formed, or when it present from the beginning, there appears to be a competition for surface sites.
Assessment of the photo-activity of cement/TiO2 for NOx abatement, based on NO2 monitoring, should involve nitrite and nitrate analysis since this acidic oxide is efficiently removed by adsorption in the dark. Adsorbed NO2 undergoes a photocatalytic oxidation to nitrate. Among important parameters concerning the measurement of the photocatalytic activity are the humidity level, the gas residence time inside the reactor and light intensity.

Online publication: 2011-07-01
Publication type : full_text
Public price (Euros): 0.00