- capturing and removing CO2 from dilute sources including point source emissions, air, and water to produce solid carbonates
- multi-component cation removal from alkaline wastewater streams containing Ca2+, Mg2+, Li+, Na+, and K+ using CO2
As noted in the recent reports by the Intergovernmental Panel on Climate Change (IPCC), there is an urgency in developing pathways to remove carbon from point source emissions, air, and water resources. One of the durable solutions to remove CO2 is via integrated CO2 capture and carbon mineralization in which CO2 is converted into water-insoluble solid carbonates. This approach is thermodynamically favorable and occurs at temperatures below 95°C. Researchers at Cornell University have studied the capture and conversion of CO2 to produce calcium and magnesium carbonates with a wide range of materials including oxides, hydroxides, and silicates bearing calcium and magnesium, and alkaline industrial residues including fly ash and slags. In this approach, CO2 capture and solubility are enhanced using solvents such as amino acid and amine solvents, which increase the concentration of (bi)carbonate species and aid in the accelerated conversion of Ca- and Mg-bearing solids into carbonates. Furthermore, the solvents are regenerated as CO2 in the gas and aqueous phases are depleted due to solid carbonate formation. Our approaches have shown that near-complete conversion of calcium and magnesium oxide, hydroxides (when present in alkaline industrial residues, ores, or as relatively pure precursors) are converted into solid carbonates at temperatures below 95°C, ~1-2 M concentrations of solvents (e.g., sodium glycinate) within 3 hours in CO2 bearing flue gas – aqueous solvent – alkaline rock or mineral environments. Process parameters such as temperature, fluid-mineral composition, and the aqueous solvent composition can be tuned to accelerate the time scales of single-step CO2 capture and carbon mineralization. The results indicate that the amino acid salt undergoes multiple CO2 capture and regeneration cycles in the aqueous phase, facilitating greater aqueous carbon species for carbonate precipitation.
- Durable carbon storage at low reaction temperature using environmentally benign regenerable solvents. The approach can be used to reduce the alkalinity of hazardous alkaline residues, and reduce the harness of wastewater streams.
- CO2 capture and mineralization.
Name: Ryan Luebke