Issue 4, 2020

Emerging investigator series: ion diffusivities in nanoconfined interfacial water films contribute to mineral carbonation thresholds

Abstract

The dynamics and reactivity of nanoconfined fluids play critical roles across a wide range of environmental and technological systems, though reaction mechanisms and kinetics are not well understood. The carbonation kinetics of forsterite (Mg2SiO4) exposed to 90 atm supercritical carbon dioxide at 35–65 °C and 85–100% relative humidity (RH) was monitored with in situ X-ray diffraction, and partner molecular dynamics simulations were used to describe the free energy landscape of Mg2+ adsorption and diffusion on forsterite surfaces covered in water films 3–10 monolayers thick. The collective findings reveal how decreasing the water film thickness by ∼1.4 monolayers, from ∼0.92 to ∼0.64 nm, inhibited reaction rates by up to 97%, promoted anhydrous Mg-carbonate (magnesite, MgCO3) precipitation, and more than doubled the apparent activation energy of carbonation. The transport simulations suggest that four monolayers are required to enable sufficiently facile Mg2+ diffusion, helping explain previously observed water film thickness-dependent reactivity thresholds.

Graphical abstract: Emerging investigator series: ion diffusivities in nanoconfined interfacial water films contribute to mineral carbonation thresholds

Supplementary files

Article information

Article type
Paper
Submitted
04 Dec. 2019
Accepted
19 Febr. 2020
First published
20 Febr. 2020

Environ. Sci.: Nano, 2020,7, 1068-1081

Author version available

Emerging investigator series: ion diffusivities in nanoconfined interfacial water films contribute to mineral carbonation thresholds

Q. R. S. Miller, J. P. Kaszuba, S. N. Kerisit, H. T. Schaef, M. E. Bowden, B. P. McGrail and K. M. Rosso, Environ. Sci.: Nano, 2020, 7, 1068 DOI: 10.1039/C9EN01382B

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements