Energy-efficient CO2 capture from a flue gas simulant is demonstrated via crystallization of structurally unique bicarbonate-water clusters with an aqueous guanidine sorbent.
Significance and Impact
Limiting global temperature rises relies on the development of energy-efficient carbon-capture methods. This novel CO2-separation cycle requires 24% less energy than industrial benchmarks based on aqueous amines.
- Experimental and computational investigations support a CO2-release mechanism consisting of proton transfer from guanidinium groups to bicarbonate anions on the crystal’s surface, with the formation of carbonic acid dimers, followed by low-energy CO2 and H2O release in the rate-limiting step.
- The minimum energy required for sorbent regeneration is 151.5 kJ/mol CO2, which is 24% lower than the regeneration energy of monoethanolamine, a benchmark industrial sorbent.
N. J. Williams et al., CO2 Capture via Crystalline Hydrogen-Bonded Bicarbonate Dimers, Chem, in press. https://doi.org/10.1016/j.chempr.2018.12.025