Repository logo
HARVEST
 

Structural Incorporation of Sorbed Molybdate during Iron(II)-Induced Transformation of Ferrihydrite and Goethite under Advective Flow Conditions

Simple item page
dc.contributor.authorSchoepfer, Valerie
dc.contributor.authorQin, Kaixuan
dc.contributor.authorRobertson, Jared M.
dc.contributor.authorDas, Soumya
dc.contributor.authorLindsay, Matthew B. J.
dc.date.accessioned2022-10-25T19:58:01Z
dc.date.available2022-10-25T19:58:01Z
dc.date.issued2020-06-08
dc.descriptionCopyright © 2020 American Chemical Societyen_US
dc.description.abstractAqueous Fe(II) can induce recrystallization of ferrihydrite and goethite [α‑FeOOH] to their more crystalline or molecularly homogenous counterparts. Despite common association with these and other Fe(III) (oxyhydr)oxides, relationships between Fe(II)-induced transformation and Mo mobility remain poorly constrained. We conducted laboratory column experiments to examine repartitioning of sorbed Mo during Fe(II)-induced transformation of ferrihydrite and goethite under advective flow conditions. We first pumped (~0.25 L d−1) artificial groundwater containing 0.1 mM MoO42− and buffered to pH 6.5 through columns packed with ferrihydrite- and goethite-coated sand until > 90 % Mo breakthrough was observed. Extended X-ray absorption fine structure (EXAFS) spectroscopy shows that initial MoO42− attenuation resulted from inner sphere complexation of MoO4 tetrahedra at ferrihydrite and goethite surfaces. We then pumped Mo-free anoxic artificial groundwater containing 0.2 mM or 2.0 mM Fe(II) through the columns until effluent Mo concentrations remained < 0.005 mM. Raman spectroscopy shows that Fe(II) introduction induced transformation of both ferrihydrite and goethite to lepidocrocite. Additionally, Fe(II) introduction mobilized 4 to 34 % of sorbed Mo and total mass release was greater for (i) ferrihydrite compared to goethite columns and (ii) low Fe(II) compared to high Fe(II) influent. Effluent pH decreased to ~5.8 for columns receiving the high Fe(II) influent and returned to pH 6.5 after 5 to 10 pore volumes. EXAFS spectroscopy indicates that structural incorporation of MoO6 octahedra into neoformed phases contributes to Mo retention during Fe(II) induced transformation. Our results offer new insight into Mo repartitioning during Fe(II)-induced transformation of Fe(III) (oxyhydr)oxides and, more generally, controls on Mo mobility in geohydrologic systems.en_US
dc.description.sponsorshipFunding was provided by the Natural Sciences and Engineering Research Council of Canada (NSERC) through a Discovery Grant held by MBJL (Grant RGPIN-2014-06589). Additional training support for K.Q. was provided by the NSERC Collaborative Research and Training Experience (CREATE) program (Grant CREAT-449124-2014). A portion of the research described in this paper was performed at the Canadian Light Source, which is supported by the Canada Foundation for Innovation, NSERC, the University of Saskatchewan, the Government of Saskatchewan, Western Economic Diversification Canada, the National Research Council Canada, and the Canadian Institutes of Health Research.en_US
dc.description.versionPeer Revieweden_US
dc.identifier.citationSchoepfer, V.A., Qin, K., Robertson, J. M., Das, S. & Lindsay, M.B.J. (2020). Structural Incorporation of Sorbed Molybdate during Iron(II)-Induced Transformation of Ferrihydrite and Goethite under Advective Flow Conditions. ACS Earth and Space Chemistry, 4(7): 1114–1126. https://doi.org/10.1021/acsearthspacechem.0c00099en_US
dc.identifier.doi10.1021/acsearthspacechem.0c00099
dc.identifier.urihttps://hdl.handle.net/10388/14267
dc.language.isoenen_US
dc.publisherAmerican Chemical Society (ACS) Publicationsen_US
dc.subjectmolybdenumen_US
dc.subjectferrihydriteen_US
dc.subjectgoethiteen_US
dc.subjectferrous ironen_US
dc.subjectrecrystallizationen_US
dc.subjectlepidocrociteen_US
dc.titleStructural Incorporation of Sorbed Molybdate during Iron(II)-Induced Transformation of Ferrihydrite and Goethite under Advective Flow Conditionsen_US
dc.typeArticleen_US

Files

Original bundle
Now showing 1 - 1 of 1
Thumbnail Image
Name:
Schoepfer et al. (2020) ACS Earth and Space Chemistry.pdf
Size:
1.06 MB
Format:
Adobe Portable Document Format
Description:
Main article - Accepted Manuscript
Download
License bundle
Now showing 1 - 1 of 1
No Thumbnail Available
Name:
license.txt
Size:
2.28 KB
Format:
Item-specific license agreed upon to submission
Description:
Download

Collections

Geological Sciences