Combined Effects of pH and Borohydride Reduction on Optical Properties of Humic Substances (HS): A Comparison of Optical Models

The combined effects of pH and borohydride reduction on the optical properties of a series of humic substances and a lignin model were examined to probe the molecular moieties and interactions that give rise to the observed optical properties of these materials. Increasing the pH from 2 to 12 produc...

Ausführliche Beschreibung

Gespeichert in:
Bibliographische Detailangaben
Veröffentlicht in:Environmental science & technology 2019-06, Vol.53 (11), p.6310-6319
Hauptverfasser: Schendorf, Tara Marie, Del Vecchio, Rossana, Bianca, Marla, Blough, Neil V
Format: Artikel
Sprache:eng
Schlagworte:
Online-Zugang:Volltext
Tags: Tag hinzufügen
Keine Tags, Fügen Sie den ersten Tag hinzu!
container_end_page 6319
container_issue 11
container_start_page 6310
container_title Environmental science & technology
container_volume 53
creator Schendorf, Tara Marie
Del Vecchio, Rossana
Bianca, Marla
Blough, Neil V
description The combined effects of pH and borohydride reduction on the optical properties of a series of humic substances and a lignin model were examined to probe the molecular moieties and interactions that give rise to the observed optical properties of these materials. Increasing the pH from 2 to 12 produced significantly enhanced absorption across the spectra of all samples, with distinct spectral responses observed over pH ranges attributable to the deprotonation of carboxylic acids and phenols. Borohydride reduction substantially attenuated the broadband absorption enhancements with pH, clearly indicating that the loss of absorption due to ketone/aldehyde reduction is coupled with the pH-dependent increase in absorption due to deprotonation of carboxylic acids and phenols. These results cannot be easily explained by a superposition of the spectra of independently absorbing chromophores (superposition model) but are readily interpretable within a charge transfer (CT) model. Changes of fluorescence emission with pH for both untreated and borohydride reduced samples suggest that a pH-dependent structural reorganization of the HS may also be influencing the fluorescence emission. Independent of optical model, these results demonstrate that chemical tests targeted to specific moieties can identify distinct structural differences among HS sources as well as provide insight into the molecular moieties and interactions that produce the observed optical and photochemical properties.
doi_str_mv 10.1021/acs.est.9b01516
format Article
fullrecord <record><control><sourceid>proquest_cross</sourceid><recordid>TN_cdi_proquest_miscellaneous_2231890155</recordid><sourceformat>XML</sourceformat><sourcesystem>PC</sourcesystem><sourcerecordid>2231890155</sourcerecordid><originalsourceid>FETCH-LOGICAL-a398t-4d55daa6195dcd2498f1eebc58a7424b246ba01a75090679822b00abb0ad966f3</originalsourceid><addsrcrecordid>eNp1kc9LHDEYhkOx1K167q0EvFhk1i_JJDvpzS7qCopSFbwN-TU0MjMZk5mDp_7rzXbXPRQKgUB4nvcL34vQFwJzApScKZPmLo1zqYFwIj6gGeEUCl5xsodmAIQVkonnffQ5pRcAoAyqT2ifERCMiXKGfi9Dp33vLL5oGmfGhEODhxVWvcU_Qgy_3mz01uGfzk5m9KHH-dwNozeqxfcxDC6O3v21VlPnDX6YdBpVb_Lbyerh23d8jvOIQUWf1nKzk2-DdW06RB8b1SZ3tL0P0NPlxeNyVdzcXV0vz28KxWQ1FqXl3ColiOTWWFrKqiHOacMrtShpqWkptAKiFhwkiIWsKNUASmtQVgrRsAN0sskdYnid8srqzifj2lb1LkypppSRSuYl8owe_4O-hCn2-XeZKhei5Dk_U2cbysSQUnRNPUTfqfhWE6jX3dS5m3ptb7vJxtdt7qQ7Z3f8exkZON0Aa3M3839xfwA0TJkF</addsrcrecordid><sourcetype>Aggregation Database</sourcetype><iscdi>true</iscdi><recordtype>article</recordtype><pqid>2247645798</pqid></control><display><type>article</type><title>Combined Effects of pH and Borohydride Reduction on Optical Properties of Humic Substances (HS): A Comparison of Optical Models</title><source>American Chemical Society Journals</source><creator>Schendorf, Tara Marie ; Del Vecchio, Rossana ; Bianca, Marla ; Blough, Neil V</creator><creatorcontrib>Schendorf, Tara Marie ; Del Vecchio, Rossana ; Bianca, Marla ; Blough, Neil V</creatorcontrib><description>The combined effects of pH and borohydride reduction on the optical properties of a series of humic substances and a lignin model were examined to probe the molecular moieties and interactions that give rise to the observed optical properties of these materials. Increasing the pH from 2 to 12 produced significantly enhanced absorption across the spectra of all samples, with distinct spectral responses observed over pH ranges attributable to the deprotonation of carboxylic acids and phenols. Borohydride reduction substantially attenuated the broadband absorption enhancements with pH, clearly indicating that the loss of absorption due to ketone/aldehyde reduction is coupled with the pH-dependent increase in absorption due to deprotonation of carboxylic acids and phenols. These results cannot be easily explained by a superposition of the spectra of independently absorbing chromophores (superposition model) but are readily interpretable within a charge transfer (CT) model. Changes of fluorescence emission with pH for both untreated and borohydride reduced samples suggest that a pH-dependent structural reorganization of the HS may also be influencing the fluorescence emission. Independent of optical model, these results demonstrate that chemical tests targeted to specific moieties can identify distinct structural differences among HS sources as well as provide insight into the molecular moieties and interactions that produce the observed optical and photochemical properties.</description><identifier>ISSN: 0013-936X</identifier><identifier>EISSN: 1520-5851</identifier><identifier>DOI: 10.1021/acs.est.9b01516</identifier><identifier>PMID: 31063364</identifier><language>eng</language><publisher>United States: American Chemical Society</publisher><subject>Absorption ; Aldehydes ; Borohydrides ; Broadband ; Carboxylic acids ; Charge transfer ; Chemical tests ; Chromophores ; Emission analysis ; Fluorescence ; Humic acids ; Humic substances ; Lignin ; Optical properties ; Organic chemistry ; pH effects ; Phenols ; Photochemicals ; Reduction ; Spectra ; Superposition (mathematics)</subject><ispartof>Environmental science &amp; technology, 2019-06, Vol.53 (11), p.6310-6319</ispartof><rights>Copyright American Chemical Society Jun 4, 2019</rights><lds50>peer_reviewed</lds50><woscitedreferencessubscribed>false</woscitedreferencessubscribed><citedby>FETCH-LOGICAL-a398t-4d55daa6195dcd2498f1eebc58a7424b246ba01a75090679822b00abb0ad966f3</citedby><cites>FETCH-LOGICAL-a398t-4d55daa6195dcd2498f1eebc58a7424b246ba01a75090679822b00abb0ad966f3</cites><orcidid>0000-0002-7938-4961 ; 0000-0001-5087-7028</orcidid></display><links><openurl>$$Topenurl_article</openurl><openurlfulltext>$$Topenurlfull_article</openurlfulltext><thumbnail>$$Tsyndetics_thumb_exl</thumbnail><linktopdf>$$Uhttps://pubs.acs.org/doi/pdf/10.1021/acs.est.9b01516$$EPDF$$P50$$Gacs$$H</linktopdf><linktohtml>$$Uhttps://pubs.acs.org/doi/10.1021/acs.est.9b01516$$EHTML$$P50$$Gacs$$H</linktohtml><link.rule.ids>314,780,784,2765,27076,27924,27925,56738,56788</link.rule.ids><backlink>$$Uhttps://www.ncbi.nlm.nih.gov/pubmed/31063364$$D View this record in MEDLINE/PubMed$$Hfree_for_read</backlink></links><search><creatorcontrib>Schendorf, Tara Marie</creatorcontrib><creatorcontrib>Del Vecchio, Rossana</creatorcontrib><creatorcontrib>Bianca, Marla</creatorcontrib><creatorcontrib>Blough, Neil V</creatorcontrib><title>Combined Effects of pH and Borohydride Reduction on Optical Properties of Humic Substances (HS): A Comparison of Optical Models</title><title>Environmental science &amp; technology</title><addtitle>Environ. Sci. Technol</addtitle><description>The combined effects of pH and borohydride reduction on the optical properties of a series of humic substances and a lignin model were examined to probe the molecular moieties and interactions that give rise to the observed optical properties of these materials. Increasing the pH from 2 to 12 produced significantly enhanced absorption across the spectra of all samples, with distinct spectral responses observed over pH ranges attributable to the deprotonation of carboxylic acids and phenols. Borohydride reduction substantially attenuated the broadband absorption enhancements with pH, clearly indicating that the loss of absorption due to ketone/aldehyde reduction is coupled with the pH-dependent increase in absorption due to deprotonation of carboxylic acids and phenols. These results cannot be easily explained by a superposition of the spectra of independently absorbing chromophores (superposition model) but are readily interpretable within a charge transfer (CT) model. Changes of fluorescence emission with pH for both untreated and borohydride reduced samples suggest that a pH-dependent structural reorganization of the HS may also be influencing the fluorescence emission. Independent of optical model, these results demonstrate that chemical tests targeted to specific moieties can identify distinct structural differences among HS sources as well as provide insight into the molecular moieties and interactions that produce the observed optical and photochemical properties.</description><subject>Absorption</subject><subject>Aldehydes</subject><subject>Borohydrides</subject><subject>Broadband</subject><subject>Carboxylic acids</subject><subject>Charge transfer</subject><subject>Chemical tests</subject><subject>Chromophores</subject><subject>Emission analysis</subject><subject>Fluorescence</subject><subject>Humic acids</subject><subject>Humic substances</subject><subject>Lignin</subject><subject>Optical properties</subject><subject>Organic chemistry</subject><subject>pH effects</subject><subject>Phenols</subject><subject>Photochemicals</subject><subject>Reduction</subject><subject>Spectra</subject><subject>Superposition (mathematics)</subject><issn>0013-936X</issn><issn>1520-5851</issn><fulltext>true</fulltext><rsrctype>article</rsrctype><creationdate>2019</creationdate><recordtype>article</recordtype><recordid>eNp1kc9LHDEYhkOx1K167q0EvFhk1i_JJDvpzS7qCopSFbwN-TU0MjMZk5mDp_7rzXbXPRQKgUB4nvcL34vQFwJzApScKZPmLo1zqYFwIj6gGeEUCl5xsodmAIQVkonnffQ5pRcAoAyqT2ifERCMiXKGfi9Dp33vLL5oGmfGhEODhxVWvcU_Qgy_3mz01uGfzk5m9KHH-dwNozeqxfcxDC6O3v21VlPnDX6YdBpVb_Lbyerh23d8jvOIQUWf1nKzk2-DdW06RB8b1SZ3tL0P0NPlxeNyVdzcXV0vz28KxWQ1FqXl3ColiOTWWFrKqiHOacMrtShpqWkptAKiFhwkiIWsKNUASmtQVgrRsAN0sskdYnid8srqzifj2lb1LkypppSRSuYl8owe_4O-hCn2-XeZKhei5Dk_U2cbysSQUnRNPUTfqfhWE6jX3dS5m3ptb7vJxtdt7qQ7Z3f8exkZON0Aa3M3839xfwA0TJkF</recordid><startdate>20190604</startdate><enddate>20190604</enddate><creator>Schendorf, Tara Marie</creator><creator>Del Vecchio, Rossana</creator><creator>Bianca, Marla</creator><creator>Blough, Neil V</creator><general>American Chemical Society</general><scope>NPM</scope><scope>AAYXX</scope><scope>CITATION</scope><scope>7QO</scope><scope>7ST</scope><scope>7T7</scope><scope>7U7</scope><scope>8FD</scope><scope>C1K</scope><scope>FR3</scope><scope>P64</scope><scope>SOI</scope><scope>7X8</scope><orcidid>https://orcid.org/0000-0002-7938-4961</orcidid><orcidid>https://orcid.org/0000-0001-5087-7028</orcidid></search><sort><creationdate>20190604</creationdate><title>Combined Effects of pH and Borohydride Reduction on Optical Properties of Humic Substances (HS): A Comparison of Optical Models</title><author>Schendorf, Tara Marie ; Del Vecchio, Rossana ; Bianca, Marla ; Blough, Neil V</author></sort><facets><frbrtype>5</frbrtype><frbrgroupid>cdi_FETCH-LOGICAL-a398t-4d55daa6195dcd2498f1eebc58a7424b246ba01a75090679822b00abb0ad966f3</frbrgroupid><rsrctype>articles</rsrctype><prefilter>articles</prefilter><language>eng</language><creationdate>2019</creationdate><topic>Absorption</topic><topic>Aldehydes</topic><topic>Borohydrides</topic><topic>Broadband</topic><topic>Carboxylic acids</topic><topic>Charge transfer</topic><topic>Chemical tests</topic><topic>Chromophores</topic><topic>Emission analysis</topic><topic>Fluorescence</topic><topic>Humic acids</topic><topic>Humic substances</topic><topic>Lignin</topic><topic>Optical properties</topic><topic>Organic chemistry</topic><topic>pH effects</topic><topic>Phenols</topic><topic>Photochemicals</topic><topic>Reduction</topic><topic>Spectra</topic><topic>Superposition (mathematics)</topic><toplevel>peer_reviewed</toplevel><toplevel>online_resources</toplevel><creatorcontrib>Schendorf, Tara Marie</creatorcontrib><creatorcontrib>Del Vecchio, Rossana</creatorcontrib><creatorcontrib>Bianca, Marla</creatorcontrib><creatorcontrib>Blough, Neil V</creatorcontrib><collection>PubMed</collection><collection>CrossRef</collection><collection>Biotechnology Research Abstracts</collection><collection>Environment Abstracts</collection><collection>Industrial and Applied Microbiology Abstracts (Microbiology A)</collection><collection>Toxicology Abstracts</collection><collection>Technology Research Database</collection><collection>Environmental Sciences and Pollution Management</collection><collection>Engineering Research Database</collection><collection>Biotechnology and BioEngineering Abstracts</collection><collection>Environment Abstracts</collection><collection>MEDLINE - Academic</collection><jtitle>Environmental science &amp; technology</jtitle></facets><delivery><delcategory>Remote Search Resource</delcategory><fulltext>fulltext</fulltext></delivery><addata><au>Schendorf, Tara Marie</au><au>Del Vecchio, Rossana</au><au>Bianca, Marla</au><au>Blough, Neil V</au><format>journal</format><genre>article</genre><ristype>JOUR</ristype><atitle>Combined Effects of pH and Borohydride Reduction on Optical Properties of Humic Substances (HS): A Comparison of Optical Models</atitle><jtitle>Environmental science &amp; technology</jtitle><addtitle>Environ. Sci. Technol</addtitle><date>2019-06-04</date><risdate>2019</risdate><volume>53</volume><issue>11</issue><spage>6310</spage><epage>6319</epage><pages>6310-6319</pages><issn>0013-936X</issn><eissn>1520-5851</eissn><abstract>The combined effects of pH and borohydride reduction on the optical properties of a series of humic substances and a lignin model were examined to probe the molecular moieties and interactions that give rise to the observed optical properties of these materials. Increasing the pH from 2 to 12 produced significantly enhanced absorption across the spectra of all samples, with distinct spectral responses observed over pH ranges attributable to the deprotonation of carboxylic acids and phenols. Borohydride reduction substantially attenuated the broadband absorption enhancements with pH, clearly indicating that the loss of absorption due to ketone/aldehyde reduction is coupled with the pH-dependent increase in absorption due to deprotonation of carboxylic acids and phenols. These results cannot be easily explained by a superposition of the spectra of independently absorbing chromophores (superposition model) but are readily interpretable within a charge transfer (CT) model. Changes of fluorescence emission with pH for both untreated and borohydride reduced samples suggest that a pH-dependent structural reorganization of the HS may also be influencing the fluorescence emission. Independent of optical model, these results demonstrate that chemical tests targeted to specific moieties can identify distinct structural differences among HS sources as well as provide insight into the molecular moieties and interactions that produce the observed optical and photochemical properties.</abstract><cop>United States</cop><pub>American Chemical Society</pub><pmid>31063364</pmid><doi>10.1021/acs.est.9b01516</doi><tpages>10</tpages><orcidid>https://orcid.org/0000-0002-7938-4961</orcidid><orcidid>https://orcid.org/0000-0001-5087-7028</orcidid></addata></record>
fulltext fulltext
identifier ISSN: 0013-936X
ispartof Environmental science & technology, 2019-06, Vol.53 (11), p.6310-6319
issn 0013-936X
1520-5851
language eng
recordid cdi_proquest_miscellaneous_2231890155
source American Chemical Society Journals
subjects Absorption
Aldehydes
Borohydrides
Broadband
Carboxylic acids
Charge transfer
Chemical tests
Chromophores
Emission analysis
Fluorescence
Humic acids
Humic substances
Lignin
Optical properties
Organic chemistry
pH effects
Phenols
Photochemicals
Reduction
Spectra
Superposition (mathematics)
title Combined Effects of pH and Borohydride Reduction on Optical Properties of Humic Substances (HS): A Comparison of Optical Models
url https://sfx.bib-bvb.de/sfx_tum?ctx_ver=Z39.88-2004&ctx_enc=info:ofi/enc:UTF-8&ctx_tim=2024-12-23T02%3A35%3A15IST&url_ver=Z39.88-2004&url_ctx_fmt=infofi/fmt:kev:mtx:ctx&rfr_id=info:sid/primo.exlibrisgroup.com:primo3-Article-proquest_cross&rft_val_fmt=info:ofi/fmt:kev:mtx:journal&rft.genre=article&rft.atitle=Combined%20Effects%20of%20pH%20and%20Borohydride%20Reduction%20on%20Optical%20Properties%20of%20Humic%20Substances%20(HS):%20A%20Comparison%20of%20Optical%20Models&rft.jtitle=Environmental%20science%20&%20technology&rft.au=Schendorf,%20Tara%20Marie&rft.date=2019-06-04&rft.volume=53&rft.issue=11&rft.spage=6310&rft.epage=6319&rft.pages=6310-6319&rft.issn=0013-936X&rft.eissn=1520-5851&rft_id=info:doi/10.1021/acs.est.9b01516&rft_dat=%3Cproquest_cross%3E2231890155%3C/proquest_cross%3E%3Curl%3E%3C/url%3E&disable_directlink=true&sfx.directlink=off&sfx.report_link=0&rft_id=info:oai/&rft_pqid=2247645798&rft_id=info:pmid/31063364&rfr_iscdi=true