(509f) CO2 Capture from Flue Gas Using Aqueous Amino Acid Salts and Mineralization into Cementitious Materials

The global cement industry accounts for approximately 8% of total CO₂ emissions. Converting these emissions into cementitious materials presents a pathway to utilizing CO₂ as a readily available feedstock while simultaneously making cement production more sustainable.

This study explores the use of amino acid salts for CO₂ capture from flue gas streams (15% CO₂) and subsequent mineralization of the captured CO₂ using electric arc furnace (EAF) slags. Amino acid salts are promising solvents for CO₂ capture due to their fast uptake kinetics and low volatility. Traditionally, their thermal regeneration has been challenging due to parasitic energy losses from water vaporization; however, coupling CO₂ capture with mineralization eliminates the need for thermal regeneration.

We investigate the performance of eight different amino acid salts by evaluating their carbamate content, CO₂ uptake flux, mineralization extent, and cyclic capacity based on mineralization. Regeneration efficiencies exceeding 90% are achieved for the amino acids, while more than 75% of the uncarbonated slag is successfully converted into carbonate forms. CO₂ fluxes from cement flue gas were measured and range between 2.3 to 4.9 × 10^-3 mol/m²/s, with K-Arg and K-Gly demonstrating the highest CO₂ fluxes. Using calorimetry, we also measure the CO₂ absorption enthalpies of these amino acid salts.

The findings of this study provide a fundamental basis for developing an efficient carbon capture technology utilizing amino acid solvents. By identifying the most effective amino acids for CO₂ capture and mineralization, this approach enables scalable CO₂ sequestration while producing valuable minerals for cement production.