A method for removing carbon dioxide directly from ambient air, using a sorbent under ambient conditions, to obtain relatively pure CO.sub.2. The CO.sub.2 is removed from the sorbent using process heat, preferably in the form of steam, at a temperature in the range of not greater than about 130 C., to capture the relatively pure CO.sub.2 and to regenerate the sorbent for repeated use. Increased efficiency can be achieved by admixing with the ambient air, prior to contacting the sorbent, a minor amount of a preferably pretreated effluent gas containing a higher concentration of carbon dioxide. The captured carbon dioxide can be stored for further use, or sequestered permanently. The above method provides purified carbon dioxide for further use in agriculture and chemical processes, or for permanent sequestration.

A system and method of reducing the net carbon dioxide footprint of an industrial process that generates power from the combustion of hydrocarbon fuels in which ambient air is admixed with up to 50% by volume of an effluent gas from the power generator of the industrial process, in order to substantially increase the CO.sub.2 concentration in the air prior to treatment. The treatment comprises adsorbing CO.sub.2 from the admixed ambient air utilizing a cooled, porous substrate-supported amine adsorbent, wherein the porous substrate initially contacts the mixed ambient air containing condensed water in its pores, which act as an intrinsic coolant with respect to the exothermic heat generated by the adsorption process. In addition, prior to regenerating the supported adsorbent, air pressure is substantially reduced in the sealed regeneration chamber and the low pressure chamber is placed in fluid connection with a higher pressure regeneration chamber containing steam and carbon dioxide, to preheat the sorbent to be regenerated and to quickly cool the regenerated sorbent prior to use for further CO.sub.2 adsorption.

A structure and system for the adsorption of carbon dioxide from air, the system comprising a sorbent structure comprising a porous substrate having a porous alumina coating on the surfaces of said substrate, and the sorbent for carbon dioxide is embedded on the surfaces of said porous alumina coating. The substrate is preferably a porous monolith, formed from silica or mesocellular foam. The sorbent is an amine group-containing material, preferably loaded at 40 to 60 percent by volume relative to the porous alumina coating.

Polymeric amine solid sorbents with enhanced stability to moisture and/or oxygen for sorptive gas separation processes are disclosed. The polymeric amine solid sorbents can be supported on a porous support or integrated into solid porous polymer networks. Sorptive gas separators can employ contactors with such polymeric amine solid sorbents for separation of a component from a multi-component gas stream.

A method for removing carbon dioxide directly from ambient air, using a sorbent under ambient conditions, to obtain relatively pure CO.sub.2. The CO.sub.2 is removed from the sorbent using process heat, preferably in the form of steam, at a temperature in the range of not greater than about 130 C., to capture the relatively pure CO.sub.2 and to regenerate the sorbent for repeated use. Increased efficiency can be achieved by admixing with the ambient air, prior to contacting the sorbent, a minor amount of a preferably pretreated effluent gas containing a higher concentration of carbon dioxide. The captured carbon dioxide can be stored for further use, or sequestered permanently. The above method provides purified carbon dioxide for further use in agriculture and chemical processes, or for permanent sequestration.

An amine-modified metal-organic framework composition is provided that has beneficial properties for performing direct air capture. The composition corresponds to a mixed-metal organic framework that includes 4,4-dioxidobiphenyl-3,3-dicarboxylate (dobpdc) as the linker. The mixed metals can correspond to two or more metals. In some aspects, the mixed-metal organic framework corresponds to M.sup.1.sub.xM.sup.2.sub.(2-x) (dobpdc). In various aspects, the mixed-metal organic framework is appended with N,N-diethylethylenediamine (e-2-e).

Systems and methods of direct air capture are described. Systems include a plurality of moving adsorber panels in a linear direction (or circular configuration) and one or more fans configured to move air across the adsorber panels; such adsorber panels may be oriented vertically or horizontally, relative to the ground. Systems may include an independent regeneration box that comprises a system of headers, ducts and valves configured to deliver and remove a plurality of gases to the regeneration box. The regeneration box contains multiple chambers such that steps such as oxygen removal and panel cooling may be performed independently from and simultaneously to thermal preheating and desorption of the CO.sub.2 on the panels. The desorption panels may be configured to achieve counter-current flow to the hot gases used for thermal preheating and desorption. A multi-stage heat pump may facilitate reuse of waste heat and decarbonization of the process heating requirements.

A method is provided for capturing CO.sub.2 from a gas mixture comprising CO.sub.2. The method includes contacting the gas mixture with a sorbent comprising a porous polymer. The porous polymer selectively binds CO.sub.2 in the gas mixture to yield bound CO.sub.2, thereby removing CO.sub.2 from the gas. Upon exposure to moisture, the porous polymer releases the bound CO.sub.2 to yield a recycled porous polymer.

Systems and methods of direct air capture are described. Systems include a plurality of moving adsorber panels in a linear direction (or circular configuration) and one or more fans configured to move air across the adsorber panels; such adsorber panels may be oriented vertically or horizontally, relative to the ground. Systems may include an independent regeneration box that comprises a system of headers, ducts and valves configured to deliver and remove a plurality of gases to the regeneration box. The regeneration box contains multiple chambers such that steps such as oxygen removal and panel cooling may be performed independently from and simultaneously to thermal preheating and desorption of the CO.sub.2 on the panels. The desorption panels may be configured to achieve counter-current flow to the hot gases used for thermal preheating and desorption. A multi-stage heat pump may facilitate reuse of waste heat and decarbonization of the process heating requirements.

A method and a system capable of removing carbon dioxide directly from ambient air, and obtaining relatively pure CO.sub.2. The method comprises the steps of generating usable and process heat from a primary production process; applying the process heat from said primary process to co-generate substantially saturated steam, alternately repeatedly exposing a sorbent to removal and to capture regeneration system phases, wherein said sorbent is alternately exposed to a flow of ambient air during said removal phase, to sorb, and therefore remove, carbon dioxide from said ambient air, and to a flow of the process steam during the regeneration and capture phase, to remove the sorbed carbon dioxide, thus regenerating such sorbent, and capturing in relatively pure form the removed carbon dioxide. The sorbent can be carried on a porous thin flexible sheet constantly in motion between the removal location and the regeneration location