Influence of environmental factors on removal of oxides of nitrogen by a photocatalytic coating
| Autor: | Maria C.G. Juenger, Richard L. Corsi, Neil E. Crain, Alexandra L. Terpeluk, Clement Cros |
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| Rok vydání: | 2015 |
| Předmět: |
Peroxyacetyl nitrate
Air Pollutants Photolysis Time Factors Ozone Light Temperature Humidity Alkenes Environment Management Monitoring Policy and Law Combustion Catalysis Propane chemistry.chemical_compound chemistry Environmental chemistry Titanium dioxide Photocatalysis Environmental science Nitrogen Oxides Relative humidity Acid rain Waste Management and Disposal NOx |
| Zdroj: | Journal of the Air & Waste Management Association. 65:937-947 |
| ISSN: | 2162-2906 1096-2247 |
| Popis: | Nitrogen oxides (NOx) emitted from combustion processes have elevated concentrations in large urban areas. They cause a range of adverse health effects, acid rain, and are precursors to formation of other atmospheric pollutants, such as ozone, peroxyacetyl nitrate, and inorganic aerosols. Photocatalytic materials containing a semi-conductor that can be activated by sunlight, such as titanium dioxide, have been studied for their ability to remove NOx. The study presented herein aims to elucidate the environmental parameters that most influence the NOx removal efficiency of photocatalytic coatings in hot and humid climate conditions. Concrete samples coated with a commercially available photocatalytic coating (a stucco) and an uncoated sample have been tested in a reactor simulating reasonable summertime outdoor sunlight, relative humidity and temperature conditions in southeast Texas. Two-level full factorial experiments were completed on each sample for five parameters. It was found that contact time, relative humidity and temperature significantly influenced both NO and NO2 removal. Elevated concentrations of organic pollutants reduced NO removal by the coating. Ultra-violet light intensity did not significantly influence removal of NO or NO2, however, ultra-violet light intensity was involved in a two-factor interaction that significantly influenced removal of both NO and NO2.Implications: The potential for removal of oxides of NOx in realistic outdoor conditions by a photocatalytic coating (a stucco) applied on concrete was studied through full factorial experimentation. Results suggest that locations offering longer contact time between the pollutant and the reactive surface would lead to greater removal. The presence of elevated relative humidity reduces the NOx removal effectiveness of the coating. Concentrations of organic pollutants in the vicinity of the material did not significantly influence its removal effectiveness, making it potentially suitable as a control strategy for NO2 near roadways, where elevated NO2 levels are observed in combination with volatile organic compounds (VOCs). |
| Databáze: | OpenAIRE |
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