TY - JOUR
T1 - Moisture-driven CO2 pump for Direct Air Capture
AU - Wade, Jennifer L.
AU - Lopez Marques, Horacio
AU - Wang, Winston
AU - Flory, Justin
AU - Freeman, Benny
N1 - Funding Information:
This material is based upon work primarily supported by the U.S. Department of Energy, Advanced Research Projects Agency-Energy (ARPA-E) under Award Number DE-AR0001103 (CO 2 and H 2 O solubility data from HLM and WW and the original model development presented herein by JW) and with support from the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under Award Number DE-SC0023343 (experimental validation by YK and JW and subsequent simulations leading to the manuscript's major conclusions by JW). The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof. The authors also thank the following investigators at the Center for Negative Carbon Emissions at Arizona State University: Yuta Kaneko for providing the experimental data to validate the membrane pump simulation and the preliminary work of the pumping membrane concept provided Isabelle Remy and Robin Abs students, all under the supervision and guidance of Professor Klaus Lackner.
Publisher Copyright:
© 2023
PY - 2023/11/5
Y1 - 2023/11/5
N2 - Direct Air Capture, the chemical separation of carbon dioxide (CO2) from air, is considered a necessary approach to generate negative carbon emissions and in turn limit global warming, though energetic and monetary costs must continue to decline to meet the needed gigaton scale. The promise of energy-efficient and continuous carbon dioxide membrane separation has only recently been investigated with the development of facilitated chemical transport and novel electrochemically driven methods. This work demonstrates the potential for continuous pumping of CO2 from air using commercial anion exchange membranes driven solely by a water vapor gradient. A reactive transport model that couples ionic transport with moisture sensitive bicarbonate chemistry in charged polymers, also termed moisture swing sorption, was developed alongside experimentally measured equilibrium and transport properties of CO2 and water vapor in Fumasep FAA-3 to determine the mass transport limits of such a system. The results show that the commercial membrane is kinetically limited by the moisture sensitive chemistry, enabling a CO2 current of 1.1 μmol/m2 ∙ s. In diffusion limited materials, a CO2 pumping flux can reach 11 μmol/m2 ∙ s in and peak performance is expected with a dry air relative humidity around 50% pumping into a saturated water vapor permeate. In all configurations, water loss becomes the major cost in such a separation and must be managed through optimal polymer design or water recovery mechanisms. The work demonstrates the applicability of a new driving force, the evaporation of water, to meet the energetic demand of CO2 separation from air.
AB - Direct Air Capture, the chemical separation of carbon dioxide (CO2) from air, is considered a necessary approach to generate negative carbon emissions and in turn limit global warming, though energetic and monetary costs must continue to decline to meet the needed gigaton scale. The promise of energy-efficient and continuous carbon dioxide membrane separation has only recently been investigated with the development of facilitated chemical transport and novel electrochemically driven methods. This work demonstrates the potential for continuous pumping of CO2 from air using commercial anion exchange membranes driven solely by a water vapor gradient. A reactive transport model that couples ionic transport with moisture sensitive bicarbonate chemistry in charged polymers, also termed moisture swing sorption, was developed alongside experimentally measured equilibrium and transport properties of CO2 and water vapor in Fumasep FAA-3 to determine the mass transport limits of such a system. The results show that the commercial membrane is kinetically limited by the moisture sensitive chemistry, enabling a CO2 current of 1.1 μmol/m2 ∙ s. In diffusion limited materials, a CO2 pumping flux can reach 11 μmol/m2 ∙ s in and peak performance is expected with a dry air relative humidity around 50% pumping into a saturated water vapor permeate. In all configurations, water loss becomes the major cost in such a separation and must be managed through optimal polymer design or water recovery mechanisms. The work demonstrates the applicability of a new driving force, the evaporation of water, to meet the energetic demand of CO2 separation from air.
KW - Diffusion-migration-reaction
KW - Direct air capture
KW - Membrane separation
KW - Moisture swing
UR - http://www.scopus.com/inward/record.url?scp=85166577251&partnerID=8YFLogxK
U2 - 10.1016/j.memsci.2023.121954
DO - 10.1016/j.memsci.2023.121954
M3 - Article
AN - SCOPUS:85166577251
SN - 0376-7388
VL - 685
JO - Journal of Membrane Science
JF - Journal of Membrane Science
M1 - 121954
ER -