230-1 Direct Air Capture of CO2 by Brucite: Effects of Iron and Manganese Doping

Session: The Power of Hard Rocks: Driving the Energy Transition and Serving Society (Posters)

Poster Booth No.: 266

Presenting Author:

Dong Youn Chung

Authors:

Chung, Dong Youn¹, Weber, Juliane², Anovitz, Lawrence Michael³, Evans, Barbara R.⁴, Yuan, Ke⁵, Adapa, Sai Krishna Reddy⁶, Boebinger, Matthew G.⁷, McGuire, Michael A.⁸, Hermann, Raphaël P.⁹, Yumnam, George¹⁰, Stubbs, Joanne¹¹, Eng, Peter J.¹², Heaney, Peter J.¹³, Stack, Andrew G.¹⁴

(1) Pennsylvania State University, State College, PA, USA, (2) Oak Ridge National Laboratory, Oak Ridge, TN, USA, (3) Oak Ridge National Laboratory, Oak Ridge, TN, USA, (4) Oak Ridge National Laboratory, Oak Ridge, TN, USA, (5) Oak Ridge National Laboratory, Oak Ridge, TN, USA, (6) Oak Ridge National Laboratory, Oak Ridge, TN, USA, (7) Oak Ridge National Laboratory, Oak Ridge, TN, USA, (8) Oak Ridge National Laboratory, Oak Ridge, TN, USA, (9) Oak Ridge National Laboratory, Oak Ridge, TN, USA, (10) Oak Ridge National Laboratory, Oak Ridge, TN, USA, (11) University of Chicago GSECARS, Lemont, IL, USA, (12) University of Chicago GSECARS, Lemont, IL, USA, (13) Pennsylvania State University, State College, PA, USA, (14) Oak Ridge National Laboratory, Oak Ridge, TN, USA,

Abstract:

Brucite (Mg(OH)₂) is a promising sorbent for direct air capture (DAC) of CO₂ because of its availability and low calcination temperatures. However, natural and synthetic brucites tend to contain metal impurities, such as iron or manganese, and the effects of these impurities on CO₂ DAC are uncertain. Here, the impact of low concentrations of iron and manganese impurities on the carbonation efficiency of brucite was examined. Brucite with small amounts (1-5 mol%) of Fe and Mn was synthesized. The increasing substitution of Fe into brucite was accompanied by the oxidation of Fe. We suggest that the most plausible location of the impurities in the doped brucites is in the octahedral sites as a substitution for Mg²⁺. The phase transformation sequence during the carbonation was found to be: brucite → amorphous magnesium carbonate → nesquehonite, regardless of impurity concentration. Both the Fe- and Mn-doped brucite samples were more reactive than endmember brucite, possibly due to their higher surface areas and lower stabilities. During carbonation, 3 mol% Fe- and Mn-doped brucites showed the highest reactivity. The variance in reactivity for Mn-doped brucites was less than that of Fe-doped brucites.

Geological Society of America Abstracts with Program. Vol. 57, No. 6, 2025

doi: 10.1130/abs/2025AM-7942

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