Hybrid Absorption–Crystallization Strategies for the Direct Air Capture of CO2 Using Phase-Changing Guanidium Bases: Insights from in Operando X-ray Scattering and Infrared Spectroscopy Measurements

Journal Article · Wed Nov 11 00:00:00 EST 2020 · Industrial and Engineering Chemistry Research

DOI:https://doi.org/10.1021/acs.iecr.0c03863· OSTI ID:1712703

Liu, Meishen ^[1]; Custelcean, Radu ^[2]; Seifert, Soenke ^[3]; Kuzmenko, Ivan ^[3]; Gadikota, Greeshma ^[1]

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1. Cornell Univ., Ithaca, NY (United States)
2. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
3. Argonne National Lab. (ANL), Lemont, IL (United States)

Efforts to limit rising concentrations of CO₂ have motivated the development of negative emission technologies. Direct air capture (DAC) of CO₂ is one of the negative emissions technologies that has been proposed for the direct removal of CO₂ from the atmosphere. Phase-changing bis(iminonoguanidine) (BIG) sorbents have been developed for the direct air capture of CO₂. These phase changing sorbents, specifically glyoxal-bis(iminoguanidine) (GBIG), involve (1) CO₂ absorption with aqueous amino acid salts, such as K- or Na-glycinate to yield bicarbonate-rich solutions, (2) crystallization of the bicarbonate anions with a BIG solid, which regenerates the amino acid, and (3) solid-state CO₂ release from the carbonate crystals and BIG regeneration. Despite the promising potential of these materials, their structural evolution during the thermal regeneration of the BIG solids, chemical regeneration of the sodium or potassium glycinate solvents, and the crystallization behavior of CO₂-loaded BIG bicarbonate remain to be evaluated and understood in detail. The aim of this study is to probe these knowledge gaps. In situ wide-angle X-ray Scattering (WAXS) results show that CO₂ and water molecules in GBIG bicarbonate are simultaneously released in a single step during the thermal regeneration of the sorbent at 97 – 134 °C. In situ ATR-FTIR measurements showed that sodium glycinate and GBIG bicarbonate are simultaneously generated when GBIG, glycine, and sodium bicarbonate are reacted. The crystallization of GBIG bicarbonate from GBIG and CO₂-loaded monoethanolamine (MEA) occurs rapidly in the first 10 min of the reaction, as determined using in situ GI-SAXS measurements. Overall, the insights from these studies are essential for the scalable implementation of CO₂ capture technologies using these phase-changing sorbents.

• Research Organization: Argonne National Laboratory (ANL), Argonne, IL (United States); Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES). Chemical Sciences, Geosciences & Biosciences Division
• Grant/Contract Number: AC02-06CH11357; AC05-00OR22725
• OSTI ID: 1712703
• Alternate ID(s): OSTI ID: 1818451
• Journal Information: Industrial and Engineering Chemistry Research, Journal Name: Industrial and Engineering Chemistry Research Journal Issue: 47 Vol. 59; ISSN 0888-5885
• Publisher: American Chemical Society (ACS)
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
Salts
bis(iminonoguanidines)
crystallization
direct air capture
phase changing sorbents
regeneration
sorbents