Decreasing Hygroscopicity Slows Forsterite Carbonation under Low-Water Conditions

• DOI: 10.1021/acs.est.5c01695
• Publication Date: 2025-04-28T20:00:26Z
• Authors: Bavan P. Rajan; Sebastian T. Merg...; Mark E. Bowden; Kelly A. Peterson; Sarah D. Burton; Geoffrey M. Bowers; Thomas W. Wietsma; Trent R. Graham; Odeta Qafoku; Christopher J. Th...; Sebastien N. Kerisit; John S. Loring
• Keywords: Forsterite

A fundamental understanding of processes that slow divalent metal silicate carbonation is important for developing effective strategies to durably store carbon dioxide and mitigate atmospheric CO2. This study presents a detailed investigation passivation effect unique low-water conditions during the forsterite (Mg2SiO4) highlights importance hygroscopicity in influencing carbonation. Integrated situ ex experimental results showed decrease rate observed after ∼10 h humid supercritical CO2 (50 °C, 90 bar) correlates with reduction water film thickness, particular, weakly hydrogen bonded adsorbed facilitates ion transport. We attribute thickness drop concentrations hygroscopic Mg2+, MgHCO3+, HCO3- ions within as predominate product evolves from amorphous magnesium carbonate (AMC) magnesite (MgCO3). When more soluble AMC present, are higher, drawing phase surface. Carbonation rates faster because thicker films can better mobilize growing carbonates. In contrast, when less predominates, lower, thinner, slower.