Calcium (Ca)-Based Solid Sorbents for Low Temperature CO₂ Capture

Principal Investigator

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At a Glance

White and her group are developing novel calcium (Ca)-based solid sorbents that are capable of selectively capturing carbon dioxide (CO₂ ) from a mixed gas stream, or air, at ambient temperature. By understanding the solution chemistry during synthesis, the researchers have obtained phase pure Ca-based layered double hydroxides and demonstrated that these sorbents can selectively adsorb CO₂ . Ongoing efforts are focused on engineering energy-efficient regeneration methods and quantifying life cycle environmental and economic aspects. This project aligns with bp’s goal of developing solutions to decarbonize the cement production process, thereby helping cities and corporations to decarbonize.

 

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Research Highlight

To reach net-zero by 2050, it is imperative that capturing CO₂ both directly from the air and at point sources become routine approaches. However, current capture technologies are comparatively expensive and have yet to be widely implemented. High costs are associated with the capture material and with the energy required for the release of CO₂ after capture, a process called regeneration. Solid sorbents are ideal for CO₂ capture, but at present there is a lack of inexpensive sorbents for low temperature capture that selectively adsorb CO₂ from a mixed gas stream (or air) and that require lower energy for their regeneration.

White and her group have recently begun research on layered double hydroxides (LDHs). These are a class of materials that have been assessed for intermediate temperature capture using calcined LDHs, yet low temperature capture using Ca-based LDHs remains unexplored. The White group successfully synthesized phase pure CaAl- and CaFe-LDHs for low temperature CO₂ capture by uncovering the complex speciation chemistry that occurs during solution-based synthesis. They have also manufactured Ca-based LDH gas filters consisting of the LDH phase deposited on carbon substrates using an electrodeposition synthesis approach.

Ongoing research is focused on determining the mechanisms and the strength of gas molecule binding (gas-solid interactions) using first principles calculations validated against experimental data. Other research explores various methods for material regeneration (i.e., release of CO₂ after capture), and quantifying capture capacity and cyclability.