Trace CO<sub>2</sub> capture by an ultramicroporous physisorbent with low water affinity.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 31819904.
- Also identified by DOI 10.1126/sciadv.aax9171 and PMC identifier 6884411.
- Licence recorded as CC BY-NC.
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Abstract
CO<sub>2</sub> accumulation in confined spaces represents an increasing environmental and health problem. Trace CO<sub>2</sub> capture remains an unmet challenge because human health risks can occur at 1000 parts per million (ppm), a level that challenges current generations of chemisorbents (high energy footprint and slow kinetics) and physisorbents (poor selectivity for CO<sub>2</sub>, especially versus water vapor, and/or poor hydrolytic stability). Here, dynamic breakthrough gas experiments conducted upon the ultramicroporous material SIFSIX-18-Ni-β reveal trace (1000 to 10,000 ppm) CO<sub>2</sub> removal from humid air. We attribute the performance of SIFSIX-18-Ni-β to two factors that are usually mutually exclusive: a new type of strong CO<sub>2</sub> binding site and hydrophobicity similar to ZIF-8. SIFSIX-18-Ni-β also offers fast sorption kinetics to enable selective capture of CO<sub>2</sub> over both N<sub>2</sub> (<i>S</i> <sub>CN</sub>) and H<sub>2</sub>O (<i>S</i> <sub>CW</sub>), making it prototypal for a previously unknown class of physisorbents that exhibit effective trace CO<sub>2</sub> capture under both dry and humid conditions.