A method for desulfurizing and decarbonizing a flue gas includes: feeding a boiler flue gas after denitrating and dedusting to a water cooler; cooling the boiler flue gas in the water cooler to a temperature near room temperature, and discharging condensed water; feeding a wet flue gas to a washing tower; washing and cooling the wet flue gas with a washing liquid to separate H.sub.2O, SO.sub.2 and CO.sub.2 in a solid form from the flue gas; feeding a solid-liquid mixed slurry from a bottom of the washing tower to a solid-liquid separator to separate solid H.sub.2O, SO.sub.2 and CO.sub.2 from the washing liquid; feeding the solid H.sub.2O, SO.sub.2 and CO.sub.2 to a rectification separation column; separating CO.sub.2 from SO.sub.2 and H.sub.2O by a reboiler at a bottom of the rectification separation column; and discharging CO.sub.2, SO.sub.2 and H.sub.2O.

A method for desulfurizing and decarbonizing a flue gas includes: feeding a boiler flue gas after denitrating and dedusting to a water cooler; cooling the boiler flue gas in the water cooler to a temperature near room temperature, and discharging condensed water; feeding a wet flue gas to a washing tower; washing and cooling the wet flue gas with a washing liquid to separate H.sub.2O, SO.sub.2 and CO.sub.2 in a solid form from the flue gas; feeding a solid-liquid mixed slurry from a bottom of the washing tower to a solid-liquid separator to separate solid H.sub.2O, SO.sub.2 and CO.sub.2 from the washing liquid; feeding the solid H.sub.2O, SO.sub.2 and CO.sub.2 to a rectification separation column; separating CO.sub.2 from SO.sub.2 and H.sub.2O by a reboiler at a bottom of the rectification separation column; and discharging CO.sub.2, SO.sub.2 and H.sub.2O.

Provided herein are metal organic frameworks comprising metal nodes and N-donor organic ligands which have high selectivity and stability in the present of gases and vapors including H.sub.2S, H.sub.2O, and CO.sub.2. Methods include capturing one or more of H.sub.2S, H.sub.2O, and CO.sub.2 from fluid compositions, such as natural gas.

The present invention discloses a method for ammonium-enhanced flue gas desulfurization (FGD) by using red mud slurry. The method specifically includes: crushing red mud, sieving the crushed red mud, slurrying the red mud, conducting aeration treatment, adding an ammonium salt and/or ammonia, and conducting natural sedimentation to obtain pretreated red mud slurry and pretreated red mud liquor; adding an ammonium salt and/or ammonia to the slurry, adding water and conducting uniform mixing, conducting pre-FGD, conducting deep desulfurization on treated flue gas by using the pretreated red mud liquor, and directly discharging desulfurized flue gas; and charging the pretreated red mud slurry and the pretreated red mud liquor obtained after the treatment to a replacement tank below, adding lime milk to the replacement tank, conducting stirring and natural sedimentation, conducting soilization on subnatant thick red mud slurry, and refluxing the supernatant to a red mud aeration tank.

The present invention discloses a method for ammonium-enhanced flue gas desulfurization (FGD) by using red mud slurry. The method specifically includes: crushing red mud, sieving the crushed red mud, slurrying the red mud, conducting aeration treatment, adding an ammonium salt and/or ammonia, and conducting natural sedimentation to obtain pretreated red mud slurry and pretreated red mud liquor; adding an ammonium salt and/or ammonia to the slurry, adding water and conducting uniform mixing, conducting pre-FGD, conducting deep desulfurization on treated flue gas by using the pretreated red mud liquor, and directly discharging desulfurized flue gas; and charging the pretreated red mud slurry and the pretreated red mud liquor obtained after the treatment to a replacement tank below, adding lime milk to the replacement tank, conducting stirring and natural sedimentation, conducting soilization on subnatant thick red mud slurry, and refluxing the supernatant to a red mud aeration tank.

A carbon dioxide fixation method includes a step of preparing a calcium-containing substance containing calcium, a step of preparing a calcium extraction substance for extracting calcium ions from the calcium-containing substance by a reaction with the calcium-containing substance to produce a calcium-containing intermediate, a step of producing a gel including the calcium-containing intermediate, by mixing the calcium-containing substance and the calcium extraction substance, a step of supplying a basic substance and carbon dioxide to the gel including the calcium-containing intermediate to precipitate calcium carbonate which is slightly soluble, and a step of removing the precipitated calcium carbonate.

A carbon dioxide fixation method includes a step of preparing a calcium-containing substance containing calcium, a step of preparing a calcium extraction substance for extracting calcium ions from the calcium-containing substance by a reaction with the calcium-containing substance to produce a calcium-containing intermediate, a step of producing a gel including the calcium-containing intermediate, by mixing the calcium-containing substance and the calcium extraction substance, a step of supplying a basic substance and carbon dioxide to the gel including the calcium-containing intermediate to precipitate calcium carbonate which is slightly soluble, and a step of removing the precipitated calcium carbonate.

Embodiments of the present disclosure are directed to systems and methods for removing formaldehyde from indoor air. Some embodiments include flowing an indoor airflow over and/or through a solid supported amine filtering medium, such that, at least a portion of formaldehyde entrained in the indoor airflow is removed therefrom. Some other embodiments include systems having one or more fans for providing velocity to one and/or another airflows (e.g., airflows to/from a formaldehyde filter).

Embodiments of the present disclosure are directed to systems and methods for removing formaldehyde from indoor air. Some embodiments include flowing an indoor airflow over and/or through a solid supported amine filtering medium, such that, at least a portion of formaldehyde entrained in the indoor airflow is removed therefrom. Some other embodiments include systems having one or more fans for providing velocity to one and/or another airflows (e.g., airflows to/from a formaldehyde filter).

The present disclosure is directed to the integration of direct air capture of carbon dioxide with thermochemical water splitting, the latter optionally driven by solar energy. The disclosure is also directed to a process comprising extracting carbon dioxide from an air stream by contacting the air-stream with an alkali metal ion-transition metal oxide of empirical formula A.sub.xMO.sub.2 (0.1<x≤1), where A represents the alkali metal ion comprising sodium ion, potassium ion, or a combination thereof and M comprises iron, manganese, or a combination thereof to form a transition metal composition comprising an oxidized ion extracted-transition metal oxide.