| Autor: |
Tomáš Bučko, Manoj Silva, Jonas Baltrusaitis, Huijie Tian, Karolina Barcauskaite, Donata Drapanauskaite |
| Rok vydání: |
2020 |
| Předmět: |
|
| Zdroj: |
ACS Earth and Space Chemistry. 4:1018-1028 |
| ISSN: |
2472-3452 |
| DOI: |
10.1021/acsearthspacechem.0c00051 |
| Popis: |
Population growth is necessitating a significant increase in crop production, while regulations require less use of nitrogen (N) (as fertilizers, such as urea) to minimize its environmental influx. A large fraction of applied N fertilizers is currently lost with significant negative environmental effects. The urea decomposition pathways explored in the literature chiefly concern the gas emissions but provide less mechanistic insights into the urea particle/soil interface after deposition and during their environmental processing (aging). The present work investigated the mechanistic role of relative humidity (RH) at the model humic material (salicylic acid)–urea interface and the resulting surface reactions using dynamic vapor sorption and in situ spatially resolved Raman spectroscopy, combined with ab initio thermodynamic calculations. The formation of a reaction product between urea and salicylic acid, used as a model compound of humic substances, was observed, resulting in the profoundly different response to RH, with the hysteresis due to the bulk urea no longer apparent. Ab initio and resulting NH3 emission measurement experiments suggest a decreased propensity of such reaction products to hydrolyze due to the formation of strong molecular bonds between urea and salicylic acid at the interface. The reaction was facilitated by the formation of a supersaturated layer of aqueous urea on the surface, which is likely the driving force behind the new product formation due to its higher vapor pressure. The results suggest that RH-driven reactions of urea and humic substances of soil could profoundly influence gas-phase emissions and thus affect the global nitrogen cycle. The impact of the stabilizing structure and the properties of the resulting urea reaction products on organic moieties needs to be further studied in the future to better understand the implications toward global N cycle. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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