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Updated: Jan 18, 2026

Author Spotlight: Magnetometric Characterization of Intermediates in the Solid-State Electrochemistry of Redox-Active Metal-Organic Frameworks
Published on: June 9, 2023
Redox-Driven Fe Atom Exchange at the Magnetite-Water Interface: Insights from 57Fe-Mössbauer Spectroscopy and
Fei Wu1,2, Jing Sun2, Jimei Zhou3
1Engineering Research Center for Clean Production of Textile Printing and Dyeing, Ministry of Education, Wuhan Textile University, Wuhan 430073, China.
Abstract:
Magnetite (Fe3O4) plays a pivotal role in the biogeochemical cycling of iron (Fe) and contaminant fate through interfacial electron transfer processes. While aqueous Fe(II)-magnetite interactions drive these environmentally critical redox reactions, the atomistic mechanisms governing electron transfer and isotopic exchange between aqueous Fe(II) and structural Fe(III) in magnetite during recrystallization remain elusive. Herein, this study combined Fe isotopic tracer experiments, 57Fe-Mössbauer spectroscopy and molecular dynamics simulations to investigate the structural controls on Fe(II)-catalyzed magnetite recrystallization under circumneutral conditions. The results demonstrate that Fe(II)aq exchanges with structural Fe(III) in magnetite, with the extent increasing for smaller particle sizes and nonstoichiometric compositions. Mössbauer spectra demonstrate preferential Fe atom exchange at octahedral sites. Molecular simulations further identify the most stable surface configurations of Fe(II) on magnetite: a monodentate mononuclear inner-sphere complex at tetrahedral sites versus a tridentate inner-sphere complex (stabilized by cation bridging) at octahedral sites. Calculated desorption free energies (0.37 eV vs 0.67 eV) confirm stronger Fe(II) retention at octahedral sites. These mechanistic insights advance the fundamental understanding of Fe(II)-catalyzed mineral transformations and inform the rational design of magnetite-based remediation strategies.
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