Ti02 in Road Pavements Reduces Nox
TiO2 in Road Pavement Reduces NOx
Abstract: The objective of this study is to test the hypothesis that titanium dioxide (TiO2) can function as a photo catalytic compound when used in the preparation of warm-mix asphalt (WMA). The proposed asphalt mixture would combine the benefits of WMA such as reduced energy consumption and emission during production with the photo catalytic properties of TiO2 to trap and degrade organic and inorganic particles in the air. Two application methods were evaluated, using TiO2 as a modifier to asphalt binder in the preparation of WMA and applying TiO2 to the pavement surface as a water-based solution. Results of the experimental program indicated that the use of TiO2 as a modifier to asphalt binder was not effective in removing NOx pollutants from the air stream; however, the application of TiO2 as part of a water-based spray coating achieved a NOx reduction efficiency ranging from 39 to 52%. Pollution from exhaust gases is hazardous to people’s health and is one of the major problems in our cities. Pollutants, especially nitrogen oxide (NOx), increase the risk of airway infections and can also impair the function of an airway. The largest quantity of NOx is emitted from road traffic and thus in the direct surrounding of the people. Especially in summer, these nitrogen oxides are the reason for formation of harmful to health ozone in near-ground layers. This nano-crystalline titanium dioxide is a photo catalyst. Activated by daylight the photo catalytic reaction results in oxidizing reagents converting hazardous NOx into harmless NO3 -. During sunny weather, the air can be cleaned by photo catalysis as it leads to elimination of up to 90% of nitrogen oxides, aldehydes, benzenes and chlorinated aromatic compounds. Even when the weather is bad, the sun is not directly shining and the UV radiation is low, up to 70% of the pollutants are still eliminated. The photo catalytic reaction can be repeated at any time without consuming the
Abstract: The objective of this study is to test the hypothesis that titanium dioxide (TiO2) can function as a photo catalytic compound when used in the preparation of warm-mix asphalt (WMA). The proposed asphalt mixture would combine the benefits of WMA such as reduced energy consumption and emission during production with the photo catalytic properties of TiO2 to trap and degrade organic and inorganic particles in the air. Two application methods were evaluated, using TiO2 as a modifier to asphalt binder in the preparation of WMA and applying TiO2 to the pavement surface as a water-based solution. Results of the experimental program indicated that the use of TiO2 as a modifier to asphalt binder was not effective in removing NOx pollutants from the air stream; however, the application of TiO2 as part of a water-based spray coating achieved a NOx reduction efficiency ranging from 39 to 52%. Pollution from exhaust gases is hazardous to people’s health and is one of the major problems in our cities. Pollutants, especially nitrogen oxide (NOx), increase the risk of airway infections and can also impair the function of an airway. The largest quantity of NOx is emitted from road traffic and thus in the direct surrounding of the people. Especially in summer, these nitrogen oxides are the reason for formation of harmful to health ozone in near-ground layers. This nano-crystalline titanium dioxide is a photo catalyst. Activated by daylight the photo catalytic reaction results in oxidizing reagents converting hazardous NOx into harmless NO3 -. During sunny weather, the air can be cleaned by photo catalysis as it leads to elimination of up to 90% of nitrogen oxides, aldehydes, benzenes and chlorinated aromatic compounds. Even when the weather is bad, the sun is not directly shining and the UV radiation is low, up to 70% of the pollutants are still eliminated. The photo catalytic reaction can be repeated at any time without consuming the