Direct air capture of carbon dioxide with nanofluidic flows
A system for direct air capture of CO 2 (DACC) includes a membrane formed from compacted layered material and configured to draw CO 2 and H 2 O from air on a feed side of the membrane into interlayers in the membrane through gas over-solubility induced by nanopore confinement and a differential solubility of CO 2 over N 2 and O 2 in H 2 O. The membrane includes a capture side for collecting a CO 2 -enriched H 2 O flow configured to be generated on the capture side from the CO 2 and H 2 O drawn through the membrane. The relative humidity (RH) of the air loads and maintains therein at least one hydration layer of the interlayers of the compacted layered material.
1 . A system for direct air capture of CO2 (DACC), comprising:
a membrane formed from compacted layered material and configured to draw CO2 and H2O from air on a feed side of the membrane into interlayers in the membrane through gas over-solubility induced by nanopore confinement and a differential solubility of CO2 over N2 and O2 in H2O,
wherein the membrane comprises a capture side for collecting a CO2-enriched H2O flow configured to be generated on the capture side from the CO2 and H2O drawn through the membrane, wherein a relative humidity (RH) of air loads maintains at least one hydration layer in the interlayers of the compacted layered material.
2 . The system of claim 1 , wherein the membrane is further configured to maintain a predetermined RH for H2O vapor to condense into the interlayers such that N2 and 02 are restricted from passing through the membrane through the differential solubility of CO2 over N2 and O2 in H2O.
3 . The system of claim 1 , wherein the compacted layered material comprises at least one of: expandable clay and clay-derivative materials comprising montmorillonite, beidellite, nontronite, volkonskoite, hectorite, saponite, sauconite; graphene; or a graphene oxide,
wherein the expandable clay and clay-derivative materials comprise at least one of cations Na+, K+, Ca2+, Li+, Rb+, Cs+, Mg2+, or Ba2+ in the interlayers.
4 . The system of claim 1 , wherein a porosity of the compacted layered material ranges from 5% to 40% and a pore size distribution of the compacted layered material ranges from about 1 nm to about 100 nm.
5 . The system of claim 1 , wherein a dry density of the compacted layered material ranges from 1.2 g/cm3 to 1.5 g/cm3,
wherein the dry density is calculated as a dry weight of the compacted layered material divided by a bulk volume of the compacted layered material.
6 . The system of claim 1 , wherein a particle size of the compacted layered material ranges from 10 nm to 10 μm.
7 . The system of claim 1 , wherein the membrane comprises a structural support layer disposed on each of two opposed sides of the membrane.
8 . The system of claim 1 , further comprising:
at least one desiccator salt configured to absorb water from the CO2-enriched H2O flow on the capture side.
9 . The system of claim 1 , wherein a ratio of a first RH at the feed side to a second RH at the capture side is at least 5:1.
10 . The system of claim 1 , wherein a first RH at the feed side is at least 50%, and a second RH at the capture side is less than 10%.