Photochemical emission and fixation of NOX gases in soils
Nenhuma Miniatura disponível
Data
2020-02-01
Autores
Barrón, Vidal
Méndez, José M.
Balbuena, José
Cruz-Yusta, Manuel
Sánchez, Luis
Giménez, Carmen
Sacristán, Daniel
González-Guzmán, Adrián
Sánchez-Rodríguez, Antonio R.
Skiba, Ute M.
Título da Revista
ISSN da Revista
Título de Volume
Editor
Resumo
Gaseous nitrogen oxides (NOx), which result from the combustion of fossil fuels, volcanic eruptions, forest fires, and biological reactions in soils, not only affect air quality and the atmospheric concentration of ozone, but also contribute to global warming and acid rain. Soil NOx emissions have been largely ascribed to soil microbiological processes; but there is no proof of abiotic catalytic activity affecting soil NO emissions. We provide evidence of gas exchange in soils involving emissions of NOx by photochemical reactions, and their counterpart fixation through photocatalytic reactions under UV–visible irradiation. The catalytic activity promoting NOx capture as nitrate varied widely amongst different soil types, from low in quartzitic sandy soils to high in iron oxide and TiO2 rich soils. Clay soils with significant amounts of smectite also exhibited high rates of NOx sequestration and fixed amounts of N comparable to that of NO (nitric oxide) losses through biotic reactions. In these soils, a flux of 100 µg NNO m−2 h−1, as usually found in most ecosystems, could be reduced by these photochemical reactions by more than 60%. This mechanism of N fixation provides new insight into the nitrogen cycle and may inspire alternative strategies to reduce NO emissions from soils.
Descrição
Palavras-chave
Nitric oxide, Nitrogen cycle, NOx, Soil photocatalysis
Como citar
Science of the Total Environment, v. 702.