The embodiments provide an acidic gas absorbent, an acidic gas removal method, and an acidic gas removal apparatus. The absorbent absorbs an acidic gas in a large amount and hardly diffuses in air. The acidic gas absorbent according to the embodiment comprises an amine compound having a sulfonyl group and two or more amino groups.

Embodiments described herein provide methods of operating a linear contactor for absorbing contaminants from a gas stream. The gas stream flows from a first end to a second end of the linear contactor. Fresh absorbent is provided at the first end of the linear contactor based on the theoretical minimum amount of absorbent needed to remove the contaminants. Absorbent is recycled from the second end to the first end of the linear contactor. Fresh absorbent is provided at the second end based on chemical condition of the recycled absorbent. Apparatus for practicing the method is also described.

A method of capturing a target species from a gas comprises the steps of: contacting a gas containing a target species with a first absorbent solution comprising a capture species; dissolving the target species in the first absorbent solution to form a target anion; electrochemically separating the target anion from the first absorbent solution by contacting the first absorbent solution with one or more ion-exchange membranes, and transferring the target anion through an ion-exchange membrane into a second absorbent solution; and releasing at least some of the target species from the second absorbent solution. The one or more ion-exchange membranes are not permeable to the capture species, so the capture species does not pass through the one or more ion-exchange membranes. An apparatus for capturing a target species from a gas is also provided.

A method of electrochemically reducing CO.sub.2 comprises introducing a first feed stream comprising H.sub.2O to a positive electrode of an electrolysis cell comprising the positive electrode, a negative electrode, and a proton conducting membrane. A second feed stream comprising a solvent and a non polar form of a switchable polarity material is directed into a CO.sub.2 capture apparatus. A third feed stream comprising CO.sub.2 is directed into the CO.sub.2 capture apparatus to interact with the second feed stream and form a first product stream comprising the solvent and a polar form of the switchable polarity material. The first product stream is introduced to the negative electrode. A potential difference is applied between the positive electrode and the negative electrode to convert the polar form of the switchable polarity material into CO.sub.2 and the non-polar form and to form products from the CO.sub.2 and the solvent. A CO.sub.2 treatment system is also described.

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 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.

A method for scavenging airborne formaldehyde comprising a step of contacting the airborne formaldehyde with an amine compound or a salt thereof.

Embodiments described herein provide methods of operating a linear contactor for absorbing contaminants from a gas stream. The gas stream flows from a first end to a second end of the linear contactor. Fresh absorbent is provided at the first end of the linear contactor based on the theoretical minimum amount of absorbent needed to remove the contaminants. Absorbent is recycled from the second end to the first end of the linear contactor. Fresh absorbent is provided at the second end based on chemical condition of the recycled absorbent. Apparatus for practicing the method is also described.

Disclosed is a carbon dioxide absorbent and a carbon dioxide separation method using the same that greatly reduces energy consumption due to a small amount of latent heat required in regeneration of absorbents, enhances CO.sub.2 absorption rate, undergoes almost no thermal denaturation even at high temperatures while absorbing carbon dioxide, and results in a considerable reduction of the cost associated with absorption of carbon dioxide.

The present disclosure relates to a cucurbituril-polyethylenimine-silica complex, a method for preparing the same and a carbon dioxide absorbent containing the same. According to the present disclosure, a cucurbituril-polyethylenimine-silica complex may be prepared by forming a complex wherein a cucurbituril is bound to polyethylenimine and including the same inside silica, and it may be used as a carbon dioxide absorbent with superior thermal stability and prevented formation of urea.