A method for capturing CO2 from the ambient air by the use of solid tethered amine adsorbents, where the amine adsorbents are tethered to a substrate selected from the group of silica, metal oxides and polymer resins. The tethered amines are joined to the substrate by covalent bonding, achieved either by the ring-opening polymerization of aziridine on porous and non-porous supports, or by the reaction of mono-, di-, or tri-aminosilanes, with silica or a metal oxide having hydroxyl surface groups. The method includes the adsorption of CO2 from ambient air, the regeneration of the adsorbent at elevated temperatures not above 120° C. and the separation of purified CO2, followed by recycling of the regenerated tethered adsorbent for further adsorption of CO2 from the ambient atmosphere.