Provided are a carbon dioxide absorbing composition comprising an ionic material comprising a cyclic ammonium cation and a method of separating carbon dioxide using the same, and the carbon dioxide absorbing composition of the present disclosure has high thermal and chemical stability and excellent carbon dioxide absorption effect. In addition, the method of separating carbon dioxide using the carbon dioxide absorbing composition is very effective for desorption of carbon dioxide, and is a very economical method since it allows repeated use of the carbon dioxide absorbing composition.

This invention provides novel compositions comprising substituted polyamines as acid gas scrubbing solutions and methods of using the compositions in an industrial system. The invention relates to the use of such polyamine compounds in industrial processes to remove acidic contaminants from natural and industrial fluid streams, such as natural gas, combustion gas, natural gas, synthesis gas, biogas, and other industrial fluid streams. The compositions and methods of the invention are useful for removal, absorption, or sequestration of acidic contaminants and sulfide contaminants including CO.sub.2, H.sub.2S, RSH, CS.sub.2, COS, and SO.sub.2.

A filter for binding constituents of a gas stream includes a supporting member and a filter layer applied to surfaces of the supporting member. The filter layer includes a component for the physisorption of constituents, a component for the chemisorption of constituents, and a component for dissolving oil constituents which comprises ionic liquids.

A process for absorbing carbon dioxide from a gas stream containing carbon dioxide, including the steps of contacting the gas stream with an aqueous composition including a substituted heteroaromatic compound having a six-membered heteroaromatic ring with from 1 to 3 nitrogen atoms in the heteroaromatic ring and at least one substituent wherein at least one of the substituents is of formula R.sup.1NH.sub.2 wherein R.sup.1 is selected from C.sub.1 to C.sub.6 alkylene and ethers of formula R.sup.2OR.sup.3 wherein R.sup.2 and R.sup.3 are C.sub.1 to C.sub.3 alkylene.

Systems comprising a composition where an imidazole is tethered to an amine and a solvent are described herein. Methods of their preparation and use are also described herein. The methods of using the systems include the reduction of volatile compounds from gas streams and a liquid stream.

An aqueous solvent composition is provided, comprising a nucleophilic component having one or more sterically unhindered primary or secondary amine moieties, a Brnsted base component having one or more basic nitrogen moieties, a water-soluble organic solvent, and water. A biphasic composition is provided, comprising one or more carbamate compounds, one or more conjugate acids of Brnsted base, a water-soluble organic solvent, and water. A biphasic CO.sub.2 absorption process is also provided, utilizing the biphasic solvent composition.

A hydrophobic MOF-based porous liquid carbon capture absorbent is provided and includes a sterically hindered solvent and a hydrophobic MOFs modified material dispersed in the sterically hindered solvent. A mass percent of the hydrophobic MOFs modified material in the hydrophobic MOF-based porous liquid carbon capture absorbent is 5% to 20%. The hydrophobic MOFs modified material is prepared by a method comprising following steps: dispersing an MOFs material, a surface modifier and a catalyst in an organic solvent, and mixing them evenly, followed by a standing reaction to obtain the hydrophobic MOFs modified material.

A redox flow acid-gas capture system includes an electrochemical cell including a cathode configured to contact a stream including an electroactive species in an inactive state and provide a reduced stream including the electroactive species in an active state, and an anode configured to contact an adduct stream including an adduct of an electroactive species and an acid-gas and provide an oxidized stream including the electroactive species in the inactive state and the acid-gas; an absorber configured to contact the reduced stream and the acid-gas and form the adduct stream including the adduct of the electroactive species and the acid-gas; and at least one of an oxygen stripper unit, or a degasser unit configured to provide a degassed stream including the electroactive species in an inactive state, and an acid-gas stream.

A composition for absorbing carbon dioxide including an ionic liquid (A) containing a cation and an anion, and a protic compound (B) having a relative permittivity at 25 C. of 20 or more, wherein the cation at least includes a cation represented by the formula (1), the anion includes an anion where an acid dissociation constant (pKa) at 25 C. of its conjugate acid in water is 4.5 or more, and the ratio of a value obtained by multiplying the number of hydroxyl groups of the protic compound (B) by the number of moles of the protic compound (B) to the number of moles of the ionic liquid (A) [number of moles of protic compound (B)/number of moles of ionic liquid (A)] is 0.2 to 1.0: ##STR00001##
wherein R.sup.1 and R.sup.2 each independently represent a hydrogen or a C1-C6 linear alkyl group.