Evaluation of the influence of environmental conditions on the efficiency of photocatalytic coatings in the degradation of nitrogen oxides (NOx)

Evaluation of the influence of environmental conditions on the efficiency of photocatalytic coatings in the degradation of nitrogen oxides (NOx)

The incorporation of titanium dioxide (TiO2) into cement mortars generates materials with photocatalytic properties, that is, a cement matrix able to capture and degrade atmospheric pollutants like nitrogen oxides (NOx). The chemical phenomenon of NOx degradation requires the activation of TiO2 thro...

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Bibliographic Details
Published in:Building and environment Vol. 49; pp. 117 - 123
Main Authors: DE MELO, Joao V. Staub, TRICHES, Glicério
Format: Journal Article
Language:English
Published: Kidlington Elsevier 01-03-2012
Subjects:
Applied sciences
Buildings. Public works
Cements
Concretes. Mortars. Grouts
Degradation
Exact sciences and technology
General (composition, classification, performance, standards, patents, etc.)
Materials
Mortars
Nitrogen oxides
Photocatalysis
Pollutants
Relative humidity
Titanium dioxide
Nitrogen oxide
Mortar
Photocatalysis
Construction materials
Measurement result
Experimental study
Environmental conditions
Degradation
Environment impact
Nitrogen oxides
Titanium oxide
Titanium dioxide
Photocatalytic mortar
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Summary:The incorporation of titanium dioxide (TiO2) into cement mortars generates materials with photocatalytic properties, that is, a cement matrix able to capture and degrade atmospheric pollutants like nitrogen oxides (NOx). The chemical phenomenon of NOx degradation requires the activation of TiO2 through ultraviolet radiation (UV-A), as well as water and oxygen molecules necessary for the generation of hydroxyl radicals (OH times ), responsible for the degradation of NOx. While photocatalytic materials are in service they are subject to different environmental conditions with regard to the incidence of UV-A radiation, relative humidity of the air and movement of the pollutant masses by the wind. This study aims to evaluate the influence of these different environmental conditions on the efficiency of photocatalytic mortar in the degradation of NOx. Using a specifically-developed test apparatus, the efficiency of a photocatalytic mortar was tested under 27 different environmental conditions, obtained by varying the relative air humidity (30, 50 and 70%), UV-A radiation (10, 25 and 40 W/m2) and pollutant mass flow rate (1, 3 and 5 l/min). All tests were carried out with an initial concentration of nitric oxide (NO) of 20 ppmv. It was observed that the higher the levels of UV-A radiation the better the performance of the mortar in the degradation of NOx. On the other hand, higher percentages of relative humidity and flow rate caused a decrease in photocatalytic activity. The experimental results verified that the environmental conditions have a considerable influence on the efficiency of photocatalytic mortar in the degradation of NOx.
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content type line 23
ISSN:0360-1323
1873-684X
DOI:10.1016/j.buildenv.2011.09.016