Metal-organic frameworks pack enormous internal surface area into a small volume, giving CO2 molecules huge numbers of places to stick.
CO2 + Site <-> CO2-Site
capacity ~ pore surface area
- CO2 concentration — CO2 molecule density in the flue-gas or air stream being scrubbed.
- MOF binding sites — open metal sites and pores in the crystalline framework available to host CO2.
- Pore affinity — how strongly the framework's chemistry attracts a passing CO2 molecule.
- Desorption/regen rate — how fast a saturated site releases CO2 during the regeneration (heat/vacuum swing) cycle.
Direct-air-capture plants like Climeworks' use engineered sorbents with exactly this bind-then-regenerate cycle to pull CO2 straight from ambient air.