Aqueous chemical bleaching of 4-nitrophenol brown carbon by hydroxyl radicals; products, mechanism, and light absorption
<p>The reaction of hydroxyl radicals (OH) with 4-nitrophenol (4NP) in an aqueous solution was investigated at pH <span class="inline-formula">=</span> 2 and 9. The molar yield of the phenolic products quantified was ca. 0.2 at pH <span class="inline-formula"&...
| Main Authors: | , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2022-04-01
|
| Series: | Atmospheric Chemistry and Physics |
| Online Access: | https://acp.copernicus.org/articles/22/5651/2022/acp-22-5651-2022.pdf |
| _version_ | 1817990113692483584 |
|---|---|
| author | B. Witkowski P. Jain T. Gierczak |
| author_facet | B. Witkowski P. Jain T. Gierczak |
| author_sort | B. Witkowski |
| collection | DOAJ |
| description | <p>The reaction of hydroxyl radicals (OH) with 4-nitrophenol
(4NP) in an aqueous solution was investigated at pH <span class="inline-formula">=</span> 2 and 9. The molar
yield of the phenolic products quantified was ca. 0.2 at pH <span class="inline-formula">=</span> 2 and 0.4 at
pH <span class="inline-formula">=</span> 9. The yield of 4-nitrocatechol (4NC) was higher at pH <span class="inline-formula">=</span> 9. At the same time, a lower number of phenolic products was observed at pH <span class="inline-formula">=</span> 9 due to
irreversible reactions of some phenols formed at pH <span class="inline-formula">></span> 7. Mineralization investigated with a total organic carbon (TOC) analyzer
showed that after 4NP was completely consumed, approximately 85 % of the
organic carbon remained in the aqueous solution. Moreover, as inferred from
the TOC measurements and the molar yields of the phenols formed, 65 % of
the organic carbon that remained in the aqueous solution was attributed to
the non-aromatic products. The light absorption of the reaction solution
between 250 and 600 nm decreased as a result of the OH reaction with 4NP.
However, the 4NP solution showed a noticeable resistance to the chemical
bleaching reaction investigated due to the formation of light-absorbing
by-products. This phenomenon effectively prolongs the timescales of the chemical bleaching of 4NP by OH by a factor of 3–1.5 at pH 2 and 9,
respectively. The experimental data acquired indicated that both photolysis
and the reaction with OH can be important processes for the removal of
light-absorbing organic compounds from cloud water particles containing 4NP.</p> |
| first_indexed | 2024-04-14T00:54:23Z |
| format | Article |
| id | doaj.art-463de12af20b4872a32e691988629561 |
| institution | Directory Open Access Journal |
| issn | 1680-7316 1680-7324 |
| language | English |
| last_indexed | 2024-04-14T00:54:23Z |
| publishDate | 2022-04-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Atmospheric Chemistry and Physics |
| spelling | doaj.art-463de12af20b4872a32e6919886295612022-12-22T02:21:39ZengCopernicus PublicationsAtmospheric Chemistry and Physics1680-73161680-73242022-04-01225651566310.5194/acp-22-5651-2022Aqueous chemical bleaching of 4-nitrophenol brown carbon by hydroxyl radicals; products, mechanism, and light absorptionB. WitkowskiP. JainT. Gierczak<p>The reaction of hydroxyl radicals (OH) with 4-nitrophenol (4NP) in an aqueous solution was investigated at pH <span class="inline-formula">=</span> 2 and 9. The molar yield of the phenolic products quantified was ca. 0.2 at pH <span class="inline-formula">=</span> 2 and 0.4 at pH <span class="inline-formula">=</span> 9. The yield of 4-nitrocatechol (4NC) was higher at pH <span class="inline-formula">=</span> 9. At the same time, a lower number of phenolic products was observed at pH <span class="inline-formula">=</span> 9 due to irreversible reactions of some phenols formed at pH <span class="inline-formula">></span> 7. Mineralization investigated with a total organic carbon (TOC) analyzer showed that after 4NP was completely consumed, approximately 85 % of the organic carbon remained in the aqueous solution. Moreover, as inferred from the TOC measurements and the molar yields of the phenols formed, 65 % of the organic carbon that remained in the aqueous solution was attributed to the non-aromatic products. The light absorption of the reaction solution between 250 and 600 nm decreased as a result of the OH reaction with 4NP. However, the 4NP solution showed a noticeable resistance to the chemical bleaching reaction investigated due to the formation of light-absorbing by-products. This phenomenon effectively prolongs the timescales of the chemical bleaching of 4NP by OH by a factor of 3–1.5 at pH 2 and 9, respectively. The experimental data acquired indicated that both photolysis and the reaction with OH can be important processes for the removal of light-absorbing organic compounds from cloud water particles containing 4NP.</p>https://acp.copernicus.org/articles/22/5651/2022/acp-22-5651-2022.pdf |
| spellingShingle | B. Witkowski P. Jain T. Gierczak Aqueous chemical bleaching of 4-nitrophenol brown carbon by hydroxyl radicals; products, mechanism, and light absorption Atmospheric Chemistry and Physics |
| title | Aqueous chemical bleaching of 4-nitrophenol brown carbon by hydroxyl radicals; products, mechanism, and light absorption |
| title_full | Aqueous chemical bleaching of 4-nitrophenol brown carbon by hydroxyl radicals; products, mechanism, and light absorption |
| title_fullStr | Aqueous chemical bleaching of 4-nitrophenol brown carbon by hydroxyl radicals; products, mechanism, and light absorption |
| title_full_unstemmed | Aqueous chemical bleaching of 4-nitrophenol brown carbon by hydroxyl radicals; products, mechanism, and light absorption |
| title_short | Aqueous chemical bleaching of 4-nitrophenol brown carbon by hydroxyl radicals; products, mechanism, and light absorption |
| title_sort | aqueous chemical bleaching of 4 nitrophenol brown carbon by hydroxyl radicals products mechanism and light absorption |
| url | https://acp.copernicus.org/articles/22/5651/2022/acp-22-5651-2022.pdf |
| work_keys_str_mv | AT bwitkowski aqueouschemicalbleachingof4nitrophenolbrowncarbonbyhydroxylradicalsproductsmechanismandlightabsorption AT pjain aqueouschemicalbleachingof4nitrophenolbrowncarbonbyhydroxylradicalsproductsmechanismandlightabsorption AT tgierczak aqueouschemicalbleachingof4nitrophenolbrowncarbonbyhydroxylradicalsproductsmechanismandlightabsorption |