Disaggregation kinetics of a peat humic acid: mechanism and pH effects

Autores
Avena, Marcelo Javier; Wilkinson, Kevin J.
Año de publicación
2002
Idioma
inglés
Tipo de recurso
artículo
Estado
versión publicada
Descripción
Fluorescence correlation spectroscopy was used to study the disaggregation kinetics of a peat humic acid (PPHA) at several pH. FCS measures diffusion coefficients of fluorescent molecules and aggregates, thus allowing for the determination of disaggregation rates with a temporal resolution of seconds to minutes. Disaggregation was initiated by dilution of a peat concentrate consisting of a mixture containing 80% large aggregates (average hydrodynamic radius, rH, of about 300 nm) and free monomers (average rH of about 1 nm). Upon dilution at different pH values, aggregate size decreased, and the proportion of free monomers in solution increased until complete disaggregation occurred. The mechanism appeared to involve the release of monomers from the surface of the aggregates. The pH markedly affected the disaggregation rate. Complete disaggregation took 1 month at pH 3.6, took less than 1 h at pH 5.6, and was extremely rapid in alkaline solutions. The results suggested that at least two processes were operating in parallel with the overall rate being the sum of both processes. At pH higher than 4.5, the disaggregation rate increased more than 3 orders of magnitude per pH unit increase. For concentrations lower than 30 mg L-1, the equilibrium condition for the PPHA was complete disaggregation even for a pH as low as 3.6.
Fil: Avena, Marcelo Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Química del Sur. Universidad Nacional del Sur. Departamento de Química. Instituto de Química del Sur; Argentina
Fil: Wilkinson, Kevin J.. Universidad de Ginebra; Suiza
Materia
HUMIC ACIDS
KINETICS
Nivel de accesibilidad
acceso abierto
Condiciones de uso
https://creativecommons.org/licenses/by-nc-sa/2.5/ar/
Repositorio
CONICET Digital (CONICET)
Institución
Consejo Nacional de Investigaciones Científicas y Técnicas
OAI Identificador
oai:ri.conicet.gov.ar:11336/96957
Acceder
id CONICETDig_717395b0e3db8de990831bafa18d1c1d
oai_identifier_str oai:ri.conicet.gov.ar:11336/96957
network_acronym_str CONICETDig
repository_id_str 3498
network_name_str CONICET Digital (CONICET)
spelling Disaggregation kinetics of a peat humic acid: mechanism and pH effectsAvena, Marcelo JavierWilkinson, Kevin J.HUMIC ACIDSKINETICShttps://purl.org/becyt/ford/1.4https://purl.org/becyt/ford/1Fluorescence correlation spectroscopy was used to study the disaggregation kinetics of a peat humic acid (PPHA) at several pH. FCS measures diffusion coefficients of fluorescent molecules and aggregates, thus allowing for the determination of disaggregation rates with a temporal resolution of seconds to minutes. Disaggregation was initiated by dilution of a peat concentrate consisting of a mixture containing 80% large aggregates (average hydrodynamic radius, rH, of about 300 nm) and free monomers (average rH of about 1 nm). Upon dilution at different pH values, aggregate size decreased, and the proportion of free monomers in solution increased until complete disaggregation occurred. The mechanism appeared to involve the release of monomers from the surface of the aggregates. The pH markedly affected the disaggregation rate. Complete disaggregation took 1 month at pH 3.6, took less than 1 h at pH 5.6, and was extremely rapid in alkaline solutions. The results suggested that at least two processes were operating in parallel with the overall rate being the sum of both processes. At pH higher than 4.5, the disaggregation rate increased more than 3 orders of magnitude per pH unit increase. For concentrations lower than 30 mg L-1, the equilibrium condition for the PPHA was complete disaggregation even for a pH as low as 3.6.Fil: Avena, Marcelo Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Química del Sur. Universidad Nacional del Sur. Departamento de Química. Instituto de Química del Sur; ArgentinaFil: Wilkinson, Kevin J.. Universidad de Ginebra; SuizaAmerican Chemical Society2002-12info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersionhttp://purl.org/coar/resource_type/c_6501info:ar-repo/semantics/articuloapplication/pdfapplication/pdfhttp://hdl.handle.net/11336/96957Avena, Marcelo Javier; Wilkinson, Kevin J.; Disaggregation kinetics of a peat humic acid: mechanism and pH effects; American Chemical Society; Environmental Science & Technology; 36; 23; 12-2002; 5100-51050013-936XCONICET DigitalCONICETenginfo:eu-repo/semantics/altIdentifier/url/pubs.acs.org/doi/10.1021/es025582uinfo:eu-repo/semantics/altIdentifier/doi/10.1021/es025582uinfo:eu-repo/semantics/openAccesshttps://creativecommons.org/licenses/by-nc-sa/2.5/ar/reponame:CONICET Digital (CONICET)instname:Consejo Nacional de Investigaciones Científicas y Técnicas2025-09-03T09:54:20Zoai:ri.conicet.gov.ar:11336/96957instacron:CONICETInstitucionalhttp://ri.conicet.gov.ar/Organismo científico-tecnológicoNo correspondehttp://ri.conicet.gov.ar/oai/requestdasensio@conicet.gov.ar; lcarlino@conicet.gov.arArgentinaNo correspondeNo correspondeNo correspondeopendoar:34982025-09-03 09:54:20.998CONICET Digital (CONICET) - Consejo Nacional de Investigaciones Científicas y Técnicasfalse
dc.title.none.fl_str_mv Disaggregation kinetics of a peat humic acid: mechanism and pH effects
title Disaggregation kinetics of a peat humic acid: mechanism and pH effects
spellingShingle Disaggregation kinetics of a peat humic acid: mechanism and pH effects
Avena, Marcelo Javier
HUMIC ACIDS
KINETICS
title_short Disaggregation kinetics of a peat humic acid: mechanism and pH effects
title_full Disaggregation kinetics of a peat humic acid: mechanism and pH effects
title_fullStr Disaggregation kinetics of a peat humic acid: mechanism and pH effects
title_full_unstemmed Disaggregation kinetics of a peat humic acid: mechanism and pH effects
title_sort Disaggregation kinetics of a peat humic acid: mechanism and pH effects
dc.creator.none.fl_str_mv Avena, Marcelo Javier
Wilkinson, Kevin J.
author Avena, Marcelo Javier
author_facet Avena, Marcelo Javier
Wilkinson, Kevin J.
author_role author
author2 Wilkinson, Kevin J.
author2_role author
dc.subject.none.fl_str_mv HUMIC ACIDS
KINETICS
topic HUMIC ACIDS
KINETICS
purl_subject.fl_str_mv https://purl.org/becyt/ford/1.4
https://purl.org/becyt/ford/1
dc.description.none.fl_txt_mv Fluorescence correlation spectroscopy was used to study the disaggregation kinetics of a peat humic acid (PPHA) at several pH. FCS measures diffusion coefficients of fluorescent molecules and aggregates, thus allowing for the determination of disaggregation rates with a temporal resolution of seconds to minutes. Disaggregation was initiated by dilution of a peat concentrate consisting of a mixture containing 80% large aggregates (average hydrodynamic radius, rH, of about 300 nm) and free monomers (average rH of about 1 nm). Upon dilution at different pH values, aggregate size decreased, and the proportion of free monomers in solution increased until complete disaggregation occurred. The mechanism appeared to involve the release of monomers from the surface of the aggregates. The pH markedly affected the disaggregation rate. Complete disaggregation took 1 month at pH 3.6, took less than 1 h at pH 5.6, and was extremely rapid in alkaline solutions. The results suggested that at least two processes were operating in parallel with the overall rate being the sum of both processes. At pH higher than 4.5, the disaggregation rate increased more than 3 orders of magnitude per pH unit increase. For concentrations lower than 30 mg L-1, the equilibrium condition for the PPHA was complete disaggregation even for a pH as low as 3.6.
Fil: Avena, Marcelo Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Química del Sur. Universidad Nacional del Sur. Departamento de Química. Instituto de Química del Sur; Argentina
Fil: Wilkinson, Kevin J.. Universidad de Ginebra; Suiza
description Fluorescence correlation spectroscopy was used to study the disaggregation kinetics of a peat humic acid (PPHA) at several pH. FCS measures diffusion coefficients of fluorescent molecules and aggregates, thus allowing for the determination of disaggregation rates with a temporal resolution of seconds to minutes. Disaggregation was initiated by dilution of a peat concentrate consisting of a mixture containing 80% large aggregates (average hydrodynamic radius, rH, of about 300 nm) and free monomers (average rH of about 1 nm). Upon dilution at different pH values, aggregate size decreased, and the proportion of free monomers in solution increased until complete disaggregation occurred. The mechanism appeared to involve the release of monomers from the surface of the aggregates. The pH markedly affected the disaggregation rate. Complete disaggregation took 1 month at pH 3.6, took less than 1 h at pH 5.6, and was extremely rapid in alkaline solutions. The results suggested that at least two processes were operating in parallel with the overall rate being the sum of both processes. At pH higher than 4.5, the disaggregation rate increased more than 3 orders of magnitude per pH unit increase. For concentrations lower than 30 mg L-1, the equilibrium condition for the PPHA was complete disaggregation even for a pH as low as 3.6.
publishDate 2002
dc.date.none.fl_str_mv 2002-12
dc.type.none.fl_str_mv info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
http://purl.org/coar/resource_type/c_6501
info:ar-repo/semantics/articulo
format article
status_str publishedVersion
dc.identifier.none.fl_str_mv http://hdl.handle.net/11336/96957
Avena, Marcelo Javier; Wilkinson, Kevin J.; Disaggregation kinetics of a peat humic acid: mechanism and pH effects; American Chemical Society; Environmental Science & Technology; 36; 23; 12-2002; 5100-5105
0013-936X
CONICET Digital
CONICET
url http://hdl.handle.net/11336/96957
identifier_str_mv Avena, Marcelo Javier; Wilkinson, Kevin J.; Disaggregation kinetics of a peat humic acid: mechanism and pH effects; American Chemical Society; Environmental Science & Technology; 36; 23; 12-2002; 5100-5105
0013-936X
CONICET Digital
CONICET
dc.language.none.fl_str_mv eng
language eng
dc.relation.none.fl_str_mv info:eu-repo/semantics/altIdentifier/url/pubs.acs.org/doi/10.1021/es025582u
info:eu-repo/semantics/altIdentifier/doi/10.1021/es025582u
dc.rights.none.fl_str_mv info:eu-repo/semantics/openAccess
https://creativecommons.org/licenses/by-nc-sa/2.5/ar/
eu_rights_str_mv openAccess
rights_invalid_str_mv https://creativecommons.org/licenses/by-nc-sa/2.5/ar/
dc.format.none.fl_str_mv application/pdf
application/pdf
dc.publisher.none.fl_str_mv American Chemical Society
publisher.none.fl_str_mv American Chemical Society
dc.source.none.fl_str_mv reponame:CONICET Digital (CONICET)
instname:Consejo Nacional de Investigaciones Científicas y Técnicas
reponame_str CONICET Digital (CONICET)
collection CONICET Digital (CONICET)
instname_str Consejo Nacional de Investigaciones Científicas y Técnicas
repository.name.fl_str_mv CONICET Digital (CONICET) - Consejo Nacional de Investigaciones Científicas y Técnicas
repository.mail.fl_str_mv dasensio@conicet.gov.ar; lcarlino@conicet.gov.ar
_version_ 1842269280300695552
score 13.13397

Publicaciones similares