We have located links that may give you full text access.
Stochastic Simulation of Isotopic Exchange Mechanisms for Fe(II)-Catalyzed Recrystallization of Goethite.
Environmental Science & Technology 2017 June 24
Understanding Fe(II)-catalyzed transformations of Fe(III)-(oxyhydr)oxides is critical for correctly interpreting stable isotopic distributions and for predicting the fate of metal ions in the environment. Recent Fe isotopic tracer experiments have shown that goethite undergoes rapid recrystallization without phase change when exposed to aqueous Fe(II). The proposed explanation is oxidation of sorbed Fe(II) and reductive Fe(II) release coupled 1:1 by electron conduction through crystallites. Given the availability of two tracer exchange data sets that explore pH and particle size effects (e.g., Handler et al. Environ. Sci. Technol. 2014 , 48 , 11302 - 11311 ; Joshi and Gorski Environ. Sci. Technol. 2016 , 50 , 7315 - 7324 ), we developed a stochastic simulation that exactly mimics these experiments, while imposing the 1:1 constraint. We find that all data can be represented by this model, and unifying mechanistic information emerges. At pH 7.5 a rapid initial exchange is followed by slower exchange, consistent with mixed surface- and diffusion-limited kinetics arising from prominent particle aggregation. At pH 5.0 where aggregation and net Fe(II) sorption are minimal, that exchange is quantitatively proportional to available particle surface area and the density of sorbed Fe(II) is more readily evident. Our analysis reveals a fundamental atom exchange rate of ∼10(-5) Fe nm(-2) s(-1), commensurate with some of the reported reductive dissolution rates of goethite, suggesting Fe(II) release is the rate-limiting step in the conduction mechanism during recrystallization.
Full text links
Related Resources
Get seemless 1-tap access through your institution/university
For the best experience, use the Read mobile app
All material on this website is protected by copyright, Copyright © 1994-2024 by WebMD LLC.
This website also contains material copyrighted by 3rd parties.
By using this service, you agree to our terms of use and privacy policy.
Your Privacy Choices
You can now claim free CME credits for this literature searchClaim now
Get seemless 1-tap access through your institution/university
For the best experience, use the Read mobile app