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

This session examines how mafic and ultramafic rocks contribute to the energy transition by 1) generating hydrogen gas, 2) trapping CO2 through carbon mineralization, and 3) providing critical minerals for climate change mitigation and renewable energy production.

Tuesday, 21 October 2025
8:00 AM - 5:30 PM
HBGCC, Hall 1

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

Paper number: 230-0
Program: Technical Sessions
Time: 8:00 AM – 8:15 AM

Authors

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 Programs. Vol. 57, No. 6

doi: 10.1130/abs/2025AM-412946

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