Structure and composition of natural ferrihydrite nano-colloids in anoxic groundwater

Maya Engel; Vincent Noël; Samuel Pierce; Libor Kovarik; Ravi K. Kukkadapu; Juan S.Lezama Pacheco; Odeta Qafoku; J. Ray Runyon; Jon Chorover; Weijiang Zhou; John Cliff; Kristin Boye; John R. Bargar

doi:10.1016/j.watres.2023.119990

Structure and composition of natural ferrihydrite nano-colloids in anoxic groundwater

Maya Engel, Vincent Noël, Samuel Pierce, Libor Kovarik, Ravi K. Kukkadapu, Juan S.Lezama Pacheco, Odeta Qafoku, J. Ray Runyon, Jon Chorover, Weijiang Zhou, John Cliff, Kristin Boye, John R. Bargar

Research output: Contribution to journal › Article › peer-review

13 Scopus citations

Abstract

Fe-rich mobile colloids play vital yet poorly understood roles in the biogeochemical cycling of Fe in groundwater by influencing organic matter (OM) preservation and fluxes of Fe, OM, and other essential (micro-)nutrients. Yet, few studies have provided molecular detail on the structures and compositions of Fe-rich mobile colloids and factors controlling their persistence in natural groundwater. Here, we provide comprehensive new information on the sizes, molecular structures, and compositions of Fe-rich mobile colloids that accounted for up to 72% of aqueous Fe in anoxic groundwater from a redox-active floodplain. The mobile colloids are multi-phase assemblages consisting of Si-coated ferrihydrite nanoparticles and Fe(II)-OM complexes. Ferrihydrite nanoparticles persisted under both oxic and anoxic conditions, which we attribute to passivation by Si and OM. These findings suggest that mobile Fe-rich colloids generated in floodplains can persist during transport through redox-variable soils and could be discharged to surface waters. These results shed new light on their potential to transport Fe, OM, and nutrients across terrestrial-aquatic interfaces.

Original language	English (US)
Article number	119990
Journal	Water research
Volume	238
DOIs	https://doi.org/10.1016/j.watres.2023.119990
State	Published - Jun 30 2023

Keywords

EXAFS
Electron microscopy
Fe mineral
Mössbauer spectroscopy
Oxidation–reduction

ASJC Scopus subject areas

Environmental Engineering
Civil and Structural Engineering
Ecological Modeling
Water Science and Technology
Waste Management and Disposal
Pollution

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10.1016/j.watres.2023.119990

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title = "Structure and composition of natural ferrihydrite nano-colloids in anoxic groundwater",

abstract = "Fe-rich mobile colloids play vital yet poorly understood roles in the biogeochemical cycling of Fe in groundwater by influencing organic matter (OM) preservation and fluxes of Fe, OM, and other essential (micro-)nutrients. Yet, few studies have provided molecular detail on the structures and compositions of Fe-rich mobile colloids and factors controlling their persistence in natural groundwater. Here, we provide comprehensive new information on the sizes, molecular structures, and compositions of Fe-rich mobile colloids that accounted for up to 72% of aqueous Fe in anoxic groundwater from a redox-active floodplain. The mobile colloids are multi-phase assemblages consisting of Si-coated ferrihydrite nanoparticles and Fe(II)-OM complexes. Ferrihydrite nanoparticles persisted under both oxic and anoxic conditions, which we attribute to passivation by Si and OM. These findings suggest that mobile Fe-rich colloids generated in floodplains can persist during transport through redox-variable soils and could be discharged to surface waters. These results shed new light on their potential to transport Fe, OM, and nutrients across terrestrial-aquatic interfaces.",

keywords = "EXAFS, Electron microscopy, Fe mineral, M{\"o}ssbauer spectroscopy, Oxidation–reduction",

author = "Maya Engel and Vincent No{\"e}l and Samuel Pierce and Libor Kovarik and Kukkadapu, {Ravi K.} and Pacheco, {Juan S.Lezama} and Odeta Qafoku and Runyon, {J. Ray} and Jon Chorover and Weijiang Zhou and John Cliff and Kristin Boye and Bargar, {John R.}",

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year = "2023",

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doi = "10.1016/j.watres.2023.119990",

language = "English (US)",

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T1 - Structure and composition of natural ferrihydrite nano-colloids in anoxic groundwater

AU - Engel, Maya

AU - Noël, Vincent

AU - Pierce, Samuel

AU - Kovarik, Libor

AU - Kukkadapu, Ravi K.

AU - Pacheco, Juan S.Lezama

AU - Qafoku, Odeta

AU - Runyon, J. Ray

AU - Chorover, Jon

AU - Zhou, Weijiang

AU - Cliff, John

AU - Boye, Kristin

AU - Bargar, John R.

PY - 2023/6/30

Y1 - 2023/6/30

N2 - Fe-rich mobile colloids play vital yet poorly understood roles in the biogeochemical cycling of Fe in groundwater by influencing organic matter (OM) preservation and fluxes of Fe, OM, and other essential (micro-)nutrients. Yet, few studies have provided molecular detail on the structures and compositions of Fe-rich mobile colloids and factors controlling their persistence in natural groundwater. Here, we provide comprehensive new information on the sizes, molecular structures, and compositions of Fe-rich mobile colloids that accounted for up to 72% of aqueous Fe in anoxic groundwater from a redox-active floodplain. The mobile colloids are multi-phase assemblages consisting of Si-coated ferrihydrite nanoparticles and Fe(II)-OM complexes. Ferrihydrite nanoparticles persisted under both oxic and anoxic conditions, which we attribute to passivation by Si and OM. These findings suggest that mobile Fe-rich colloids generated in floodplains can persist during transport through redox-variable soils and could be discharged to surface waters. These results shed new light on their potential to transport Fe, OM, and nutrients across terrestrial-aquatic interfaces.

AB - Fe-rich mobile colloids play vital yet poorly understood roles in the biogeochemical cycling of Fe in groundwater by influencing organic matter (OM) preservation and fluxes of Fe, OM, and other essential (micro-)nutrients. Yet, few studies have provided molecular detail on the structures and compositions of Fe-rich mobile colloids and factors controlling their persistence in natural groundwater. Here, we provide comprehensive new information on the sizes, molecular structures, and compositions of Fe-rich mobile colloids that accounted for up to 72% of aqueous Fe in anoxic groundwater from a redox-active floodplain. The mobile colloids are multi-phase assemblages consisting of Si-coated ferrihydrite nanoparticles and Fe(II)-OM complexes. Ferrihydrite nanoparticles persisted under both oxic and anoxic conditions, which we attribute to passivation by Si and OM. These findings suggest that mobile Fe-rich colloids generated in floodplains can persist during transport through redox-variable soils and could be discharged to surface waters. These results shed new light on their potential to transport Fe, OM, and nutrients across terrestrial-aquatic interfaces.

KW - EXAFS

KW - Electron microscopy

KW - Fe mineral

KW - Mössbauer spectroscopy

KW - Oxidation–reduction

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Structure and composition of natural ferrihydrite nano-colloids in anoxic groundwater

Abstract

Keywords

ASJC Scopus subject areas

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