Dynamic breathing of CO2 by hydrotalcite

Area of Science:

• Geochemistry
• Environmental Science
• Materials Science

Background:

• The geological carbon cycle, involving carbonate solids like limestone, typically operates over millions of years through weathering and metamorphic processes.
• Understanding rapid carbon cycling mechanisms is crucial for climate change research.

Purpose of the Study:

• To investigate the potential for ultrarapid carbon cycling in layered double hydroxides (LDHs).
• To explore the uptake of atmospheric carbon dioxide (CO2) by LDHs under ambient conditions.

Main Methods:

• Utilized (13)C-labeling to track carbonate anion exchange within LDHs.
• Employed infrared (IR) spectroscopy to monitor the dynamic exchange process.
• Investigated the influence of humidity on the exchange rate.

Main Results:

• Carbonate anion-intercalated LDHs demonstrated an ultrarapid carbon cycle, capturing atmospheric CO2.
• Dynamic exchange between intercalated and atmospheric carbonate anions was observed with a half-life of approximately 24 hours under low humidity.
• The rate of exchange is significantly faster than conventional geological carbon cycle processes.

Conclusions:

• Hydrotalcite-like layered double hydroxides can mediate a significantly accelerated carbon cycle.
• The findings suggest that natural clay minerals may play a more dynamic role in the lithosphere-atmosphere carbon exchange than previously recognized.