Impact of adsorbed nitrate on the heterogeneous conversion of SO2 on α-Fe2O3 in the absence and presence of simulated solar irradiation
| Autor: | Chengtian Du, Assiya Zhanzakova, Shicheng Zhang, Tiantao Cheng, Hongbo Fu, Xin Yang, Lin Wang, Lingdong Kong, Songying Tong, Jianmin Chen |
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| Rok vydání: | 2019 |
| Předmět: |
Environmental Engineering
010504 meteorology & atmospheric sciences Diffuse reflectance infrared fourier transform Photodissociation chemistry.chemical_element 010501 environmental sciences Photochemistry complex mixtures 01 natural sciences Pollution Nitrogen respiratory tract diseases chemistry.chemical_compound Adsorption chemistry Nitrate Photocatalysis Environmental Chemistry Sulfate Waste Management and Disposal Dissolution 0105 earth and related environmental sciences |
| Zdroj: | Science of The Total Environment. 649:1393-1402 |
| ISSN: | 0048-9697 |
| DOI: | 10.1016/j.scitotenv.2018.08.295 |
| Popis: | Adsorbed nitrate is ubiquitous in the atmosphere, and it can undergo photolysis to produce oxidizing active radicals. Nitrate photolysis may be coupled with the oxidation conversions of atmospheric gaseous pollutants. However, the processes involved remain poorly understood. In this study, the impact of adsorbed nitrate on the heterogeneous oxidation of SO2 on α-Fe2O3 was investigated in the absence and presence of simulated solar irradiation by using in situ Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS). The results indicate that for α-Fe2O3 particles with no adsorbed nitrate, the formation of adsorbed sulfate on humid particles is stronger than that on dry particles. Meanwhile, light can also promote the heterogeneous conversion of SO2 and the formation of sulfate on dry particles because α-Fe2O3 is a typical photocatalyst. However, the heterogeneous conversion of SO2 on humid α-Fe2O3 particles is somewhat suppressed under light, suggesting the occurrence of photoinduced reductive dissolution. For the heterogeneous conversion of SO2 on α-Fe2O3 particles with adsorbed nitrate, the formation of sulfate on humid particles is still higher than that on dry particles. For the dry α-Fe2O3 particles with adsorbed nitrate, light promotes the formation of adsorbed sulfate. For the humid α-Fe2O3 particles with adsorbed nitrate, the heterogeneous conversion of SO2 under light is stronger than that under no light, indicating that the photolysis of adsorbed nitrate is coupled with the oxidation of SO2 and the formation of sulfate. The consumption of adsorbed nitrate and the formation of adsorbed N2O4 are observed during the introduction of SO2. A possible mechanism for the impact of adsorbed nitrate on the heterogeneous conversion of SO2 on α-Fe2O3 particles is proposed, and atmospheric implications based on these results are discussed. |
| Databáze: | OpenAIRE |
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