Nitrate removal using metal-acid light induced (MALI) cycle

The homogeneous Fe3+/oxalate system was examined as a Metal-Acid Light Induced (MALI) cycle for the photo-assisted reduction of nitrate (NO3). A linear correlation between NO3 concentration removal and C2O4 2 consumption, at stoichiometric conditions, was obtained. This confirmed that CO2•- radicals...

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Detalles Bibliográficos
Autores: Hahn, Vanesa Astrid, Garcia-Costa, Alicia L., Casas de Pedro, José Antonio
Tipo de recurso: artículo
Fecha de publicación:2026
País:España
Institución:Universidad Autónoma de Madrid
Repositorio:Biblos-e Archivo. Repositorio Institucional de la UAM
Idioma:inglés
OAI Identifier:oai:dnet:biblosearchi::fb536cbab62144986445b35de0a3e669
Acceso en línea:https://hdl.handle.net/10486/756700
https://dx.doi.org/10.1016/j.seppur.2026.137539
Access Level:acceso abierto
Palabra clave:Nitrate removal
Photo-assisted process
MALI cycle
iron/oxalate cycle
Nitrate reduction kinetics and mechanism
Química
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spelling Nitrate removal using metal-acid light induced (MALI) cycleHahn, Vanesa AstridGarcia-Costa, Alicia L.Casas de Pedro, José AntonioNitrate removalPhoto-assisted processMALI cycleiron/oxalate cycleNitrate reduction kinetics and mechanismQuímicaThe homogeneous Fe3+/oxalate system was examined as a Metal-Acid Light Induced (MALI) cycle for the photo-assisted reduction of nitrate (NO3). A linear correlation between NO3 concentration removal and C2O4 2 consumption, at stoichiometric conditions, was obtained. This confirmed that CO2•- radicals generated through ferrioxalate photolysis are the primary reductive species, enabling complete NO3 conversion with no detectable accumulation of NH4+ or gaseous NOX and only minor transient NO2 formation. Time-resolved kinetic experiments demonstrated that NO3 undergo pseudo-first order, whereas oxalate decomposition follows zero-order behavior governed exclusively by the photon flux. A study has been conducted on the influence of the different variables affecting the Fe-Oxalate-UV cycle. A photonic operational window was identified in Fe–oxalate systems, delineating the transition from reagent-controlled to photon-limited regimes. Outside this window, excess oxalate activated competing oxidative pathways that re-oxidized nitrogenated byproduct and decreased NO3 removal rate, thereby elucidating inconsistencies previously reported in the literature. Application to a real groundwater matrix revealed that Ca2+ induced CaC2O4 precipitation, markedly lowering UV transmittance and slowing the reaction. Mild acidification effectively suppressed precipitation restored photon utilization and produced NO3 reduction rates comparable to, and initially exceeding, those obtained in ultrapure water. These results close critical mechanistic and operational gaps in homogeneous photo-assisted NO3 reduction. The integrated kinetic, photonic and matrix-dependence framework developed here provides quantitative design guidelines for reagent dosing, light delivery and water-quality conditioning. Collectively, these insights advance the rational scale-up of the MALI cycle as a selective and practical technology for NO3 remediationAuthors thank the Spanish AEI for funding received through Grant PID2022-139063OB-I00 and PID2022-139810OA-I00 funded by MCIN/ AEI/10.13039/501100011033 and, as appropriate, by “ERDF A way of making Europe”, by the “European Union” or by the “European Union NextGenerationEU/PRTR”. A. L. Garcia-Costa thanks Comunidad de Madrid for the Cesar Nombela grant 2023-T1/ECO-29062ElsevierDepartamento de Ingeniería QuímicaFacultad de CienciasGobierno de España20262026-01-11research articlehttp://purl.org/coar/resource_type/c_2df8fbb1VoRhttp://purl.org/coar/version/c_970fb48d4fbd8a85info:eu-repo/semantics/articleapplication/pdfhttps://hdl.handle.net/10486/756700https://dx.doi.org/10.1016/j.seppur.2026.137539reponame:Biblos-e Archivo. Repositorio Institucional de la UAMinstname:Universidad Autónoma de MadridInglésengopen accesshttp://purl.org/coar/access_right/c_abf2Attribution-NonCommercial-NoDerivatives 4.0 Internationalhttp://creativecommons.org/licenses/by-nc-nd/4.0/info:eu-repo/semantics/openAccessoai:dnet:biblosearchi::fb536cbab62144986445b35de0a3e6692026-06-23T12:46:27Z
dc.title.none.fl_str_mv Nitrate removal using metal-acid light induced (MALI) cycle
title Nitrate removal using metal-acid light induced (MALI) cycle
spellingShingle Nitrate removal using metal-acid light induced (MALI) cycle
Hahn, Vanesa Astrid
Nitrate removal
Photo-assisted process
MALI cycle
iron/oxalate cycle
Nitrate reduction kinetics and mechanism
Química
title_short Nitrate removal using metal-acid light induced (MALI) cycle
title_full Nitrate removal using metal-acid light induced (MALI) cycle
title_fullStr Nitrate removal using metal-acid light induced (MALI) cycle
title_full_unstemmed Nitrate removal using metal-acid light induced (MALI) cycle
title_sort Nitrate removal using metal-acid light induced (MALI) cycle
dc.creator.none.fl_str_mv Hahn, Vanesa Astrid
Garcia-Costa, Alicia L.
Casas de Pedro, José Antonio
author Hahn, Vanesa Astrid
author_facet Hahn, Vanesa Astrid
Garcia-Costa, Alicia L.
Casas de Pedro, José Antonio
author_role author
author2 Garcia-Costa, Alicia L.
Casas de Pedro, José Antonio
author2_role author
author
dc.contributor.none.fl_str_mv Departamento de Ingeniería Química
Facultad de Ciencias
Gobierno de España
dc.subject.none.fl_str_mv Nitrate removal
Photo-assisted process
MALI cycle
iron/oxalate cycle
Nitrate reduction kinetics and mechanism
Química
topic Nitrate removal
Photo-assisted process
MALI cycle
iron/oxalate cycle
Nitrate reduction kinetics and mechanism
Química
description The homogeneous Fe3+/oxalate system was examined as a Metal-Acid Light Induced (MALI) cycle for the photo-assisted reduction of nitrate (NO3). A linear correlation between NO3 concentration removal and C2O4 2 consumption, at stoichiometric conditions, was obtained. This confirmed that CO2•- radicals generated through ferrioxalate photolysis are the primary reductive species, enabling complete NO3 conversion with no detectable accumulation of NH4+ or gaseous NOX and only minor transient NO2 formation. Time-resolved kinetic experiments demonstrated that NO3 undergo pseudo-first order, whereas oxalate decomposition follows zero-order behavior governed exclusively by the photon flux. A study has been conducted on the influence of the different variables affecting the Fe-Oxalate-UV cycle. A photonic operational window was identified in Fe–oxalate systems, delineating the transition from reagent-controlled to photon-limited regimes. Outside this window, excess oxalate activated competing oxidative pathways that re-oxidized nitrogenated byproduct and decreased NO3 removal rate, thereby elucidating inconsistencies previously reported in the literature. Application to a real groundwater matrix revealed that Ca2+ induced CaC2O4 precipitation, markedly lowering UV transmittance and slowing the reaction. Mild acidification effectively suppressed precipitation restored photon utilization and produced NO3 reduction rates comparable to, and initially exceeding, those obtained in ultrapure water. These results close critical mechanistic and operational gaps in homogeneous photo-assisted NO3 reduction. The integrated kinetic, photonic and matrix-dependence framework developed here provides quantitative design guidelines for reagent dosing, light delivery and water-quality conditioning. Collectively, these insights advance the rational scale-up of the MALI cycle as a selective and practical technology for NO3 remediation
publishDate 2026
dc.date.none.fl_str_mv 2026
2026-01-11
dc.type.none.fl_str_mv research article
http://purl.org/coar/resource_type/c_2df8fbb1
VoR
http://purl.org/coar/version/c_970fb48d4fbd8a85
dc.type.openaire.fl_str_mv info:eu-repo/semantics/article
format article
dc.identifier.none.fl_str_mv https://hdl.handle.net/10486/756700
https://dx.doi.org/10.1016/j.seppur.2026.137539
url https://hdl.handle.net/10486/756700
https://dx.doi.org/10.1016/j.seppur.2026.137539
dc.language.none.fl_str_mv Inglés
eng
language_invalid_str_mv Inglés
language eng
dc.rights.none.fl_str_mv open access
http://purl.org/coar/access_right/c_abf2
Attribution-NonCommercial-NoDerivatives 4.0 International
http://creativecommons.org/licenses/by-nc-nd/4.0/
dc.rights.openaire.fl_str_mv info:eu-repo/semantics/openAccess
rights_invalid_str_mv open access
http://purl.org/coar/access_right/c_abf2
Attribution-NonCommercial-NoDerivatives 4.0 International
http://creativecommons.org/licenses/by-nc-nd/4.0/
eu_rights_str_mv openAccess
dc.format.none.fl_str_mv application/pdf
dc.publisher.none.fl_str_mv Elsevier
publisher.none.fl_str_mv Elsevier
dc.source.none.fl_str_mv reponame:Biblos-e Archivo. Repositorio Institucional de la UAM
instname:Universidad Autónoma de Madrid
instname_str Universidad Autónoma de Madrid
reponame_str Biblos-e Archivo. Repositorio Institucional de la UAM
collection Biblos-e Archivo. Repositorio Institucional de la UAM
repository.name.fl_str_mv
repository.mail.fl_str_mv
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