Kalev Erme will defend his PhD thesis "The Effect of Catalysts in Plasma Oxidation of Nitrogen Oxides" (physics) on 6 September 2019.
dr. Indrek Jõgi (Institute of Physics, University of Tartu)
dr. Joanna Pawlat (Lublin University of Technology, Poland)
Air pollution is a growing problem in densely populated areas and an important class of compounds that contribute to the pollution is nitrogen oxides – NO and NO2. A major source of these gases is fuel combustion and upon reaching the atmosphere they can be the precursors of acid rains and have direct adverse health effects. Because of this it is important to remove nitrogen oxides from exhaust gases before they enter the atmosphere. A possibility for that is removal by plasma, which avoids some drawbacks of more widely used methods. Removal by plasma can in turn be improved by catalysts and this aspect is dealt with in the current thesis. It was found that plasma is best used only for the production of ozone, instead of directing the whole polluted gas stream through the plasma reactor. Of the catalysts that were investigated, iron oxide (Fe2O3) lead to the best results, increasing the efficiency of the process up to three times and at the same time decomposing excessive ozone, which prevented its emission into the atmosphere. The effect of the catalysts was caused by additional compounds and reaction pathways on their surfaces, which improved the efficiency of the whole process.