A carbon dioxide absorbent containing a polyamine compound (A) having an alicyclic hydrocarbon structure, wherein a content of the polyamine compound (A) is 60% by mass or more.

Provided is a composition for removal of a sulfur-containing compound in a liquid or gas, wherein the sulfur-containing compound is at least one selected from the group consisting of hydrogen sulfide and a compound containing an SH group, and the composition contains an aldehyde and a polyvalent amine represented by the general formula (1).

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.

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 invention relates to methods for improving carbon capture using entrained catalytic-particles within an amine solvent. The particles are functionalized and appended with a CO.sub.2 hydration catalyst to enhance the kinetics of CO.sub.2 hydration and improve overall mass transfer of CO.sub.2 from an acid gas.

Materials, methods of making, and methods of using a stable and regenerable immobilized amine sorbents for rare earth element and heavy metal recovery from liquid sources. Embodiments of the invention relate to the novel combination of different polyamines, primarily polyethylenimine Mw=800 (PEI.sub.800), and an epoxysilane, namely 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane (ECTMS), covalently immobilizing theREE and heavy metal-adsorbing amine sites within low cost, porous silica particles.

Methods for removing oxyanions from water according to the following steps: (i) dissolving an oxyanion precipitating compound into the aqueous source to result in precipitation of an oxyanion salt of the oxyanion precipitating compound; and (ii) removing the oxyanion salt from the water containing the oxyanion to result in water substantially reduced in concentration of the oxyanion; wherein the oxyanion precipitating compound has the following composition:

##STR00001##

wherein A is a ring-containing moiety and X.sup.m is an anionic species with a magnitude of charge m. The invention employs bis-iminoguanidinium compounds according to Formula (1a) as well as neutral precursor compounds according to Formula (1), which can be used for removing undesirable species from aqueous solutions or air, such as removal of sulfate from water and carbon dioxide from air.

The present invention relates to a hydrogen sulphide scavenging additive composition for scavenging hydrogen sulphide including sulfur containing compounds and mercaptans, particularly for scavenging hydrogen sulfide in hydrocarbons, wherein the additive composition comprises substantially reduced amount of nitrogen based hydrogen sulfide scavengers, and is also required in substantially reduced amount, and wherein the additive composition scavenges the sulfur containing compounds not only at room temperature, but also at higher temperatures, and comprises at least a combination of: (A) at least one nitrogen based hydrogen sulfide scavenger; and (B) at least one aliphatic tertiary amine, wherein the nitrogen based hydrogen sulfide scavenger comprises triazine based hydrogen sulfide scavenger. In one embodiment, it also relates to a method for scavenging hydrogen sulfide in hydrocarbons, and in another embodiment it relates to a method of using an additive composition of the present invention for scavenging hydrogen sulfide in hydrocarbons. In yet another embodiment, it relates to a composition comprising (i) a hydrocarbon and (ii) a hydrogen sulfide scavenging additive composition for scavenging hydrogen sulfide in hydrocarbons.

The invention concerns novel polyamines having formula (I) obtained from the reaction between a polyol diglycidylether and piperazine:

##STR00001##

in which n is a whole number between 0 and 30, R.sub.1 has different forms, R.sub.2 has formula (g.sub.5), and R.sub.2 has formula (g.sub.6) when n=0

##STR00002## R.sub.6: H, C1-C6 alkyl or hydroxyalkyl radical, R.sub.7: C1-C6 alkyl or hydroxyalkyl radical, R.sub.6 and R.sub.7 may be connected together to form a heterocycle having 5, 6, 7 or 8 atoms when R.sub.6 is other than H, R.sub.8: H, C1-C4 alkyl or hydroxyalkyl radical.

The invention also concerns their preparation method and their use in an absorbing solution based on amines in order to selectively eliminate H.sub.2S from a gaseous effluent containing H.sub.2S and CO.sub.2.

The present invention relates to an absorption solvent and, more particularly, to an absorption solvent for removing carbon dioxide from a gaseous mixture having high carbon dioxide partial pressure.