The present invention relates to a process and contactor vessel in which gas and liquid contact occurs to facilitate mass transfer therebetween. In one embodiment, the process includes a fluidised bed including mobile inert primary objects and secondary particles that facilitate turbulent mixing and enhanced gas/liquid surface area in the contactor.

Intensification techniques are described for enhancing biocatalytic CO.sub.2 absorption operations, and may include the use of a rotating packed bed, a rotating disc reactor, a zig-zag reactor or other reactors that utilize process intensification. Carbonic anhydrase can be deployed in the high intensity reactor free in solution, immobilized with respect to particles that flow with the liquid, and/or immobilized to internals, such as packing, that are fixed within the high intensity reactor.

An anesthetic circuit is provided for treating a patient. The anesthetic circuit includes a membrane having a plurality of hollow fibers. Also provided is a fluid separation apparatus connectable to an anesthetic circuit. In a further embodiment, a method is provided for anesthetic treatment of a patient.

Sulfurihydrogenibium sp. carbonic anhydrase (SspCA) or mutants thereof catalyze a hydration reaction of CO.sub.2 into bicarbonate and hydrogen ions or a desorption reaction to produce a CO.sub.2 gas. Sulfurihydrogenibium sp. carbonic anhydrase (SspCA) having improved thermostability in the presence of carbonate ions as compared to in the absence of carbonate ions are useful in the capture of CO.sub.2 from a CO.sub.2-containing gas.

An absorbent for selective removal of hydrogen sulfide from a fluid stream comprises an aqueous solution of a) a tertiary amine, b) a sterically hindered secondary amine of the general formula (I)

##STR00001##

in which R.sub.1 and R.sub.2 are each independently selected from C.sub.1-4-alkyl and C.sub.1-4-hydroxyalkyl; R.sub.3, R.sub.4, R.sub.5 and R.sub.6 are each independently selected from hydrogen, C.sub.1-4-alkyl and C.sub.1-4-hydroxyalkyl, with the proviso that at least one R.sub.4 and/or R.sub.5 radical on the carbon atom bonded directly to the nitrogen atom is C.sub.1-4-alkyl or C.sub.1-4-hydroxyalkyl when R.sub.3 is hydrogen; x and y are integers from 2 to 4 and z is an integer from 1 to 4; where the molar ratio of b) to a) is in the range from 0.05 to 1.0, and c) an acid in an amount, calculated as neutralization equivalent relative to the protonatable nitrogen atoms in a) and b), of 0.05 to 15.0%. One preferred amine of the formula I is 2-(2-tert-butylaminoethoxy)ethanol. The absorbent allows a defined H.sub.2S selectivity to be set at pressures of the kind typical in natural gas processing.

Methods for enzyme-enhanced CO.sub.2 capture include contacting a CO.sub.2-containing gas with an aqueous absorption solution at process conditionssuch as high temperature, high pH, and/or using carbonate-based solutionsin the presence of Thermovibrio ammonificans carbonic anhydrase (TACA) or functional derivative thereof for catalyzing the hydration reaction of CO.sub.2 into bicarbonate and hydrogen ions and/or catalyzing the desorption reaction to produce a CO.sub.2 gas. The TACA may be provided to flow with the solution to cycle through a CO.sub.2 capture system that includes an absorber and a stripper.

A method for removing SO.sub.x from a gas by using a compound alcohol-amine solution is provided. The compound alcohol-amine solution is made by mixing ethylene glycol and/or polyethylene glycol with hydroxyl and/or carboxyl organic compound having basic group containing nitrogen. The compound alcohol-amine solution is contacted with the gas containing SO.sub.x to absorb the SO.sub.x in the gas, wherein x=2 and/or 3. The compound alcohol-amine solution with absorbed SO.sub.x is regenerated by one or more of heating method, vacuum method, gas stripping method, ultrasonic method, microwave method, and radiation method to release by-products of sulfur dioxide and sulfur trioxide, and the regenerated compound alcohol-amine solution is recycled for use. This method can be used for removing SO.sub.x from flue gas, burning gas, coke-oven gas, synthesis waste gas from dyestuff plants, sewage gas from chemical fiber plants, and other industrial raw material gases or waste gases containing SO.sub.x.

A method for the treatment of a gas stream, wherein before the combustion of the gas stream, hydrogen sulfide is separated out of the gas stream in a first absorber by an absorption medium, the treated gas stream purified of hydrogen sulfide is burnt in a combustion apparatus, the carbon dioxide contained in the exhaust gas of the burnt gas stream after combustion is separated in a second absorber by an absorption medium, and the separated hydrogen sulfide and carbon dioxide are separated in at least one desorber from the absorption medium for the regeneration of the latter. The same absorption medium separates the hydrogen sulfide out of the gas stream and the carbon dioxide out of the exhaust gas. A corresponding device for the treatment of a gas stream has a first absorber and a second absorber flow-connected to one another for the exchange of absorption medium.

The present invention describes a combined liquid absorbent system to capture gaseous CO.sub.2. The said combination is given by the mixture of an IL and an amino acid aqueous solution. This mixture has an improved CO.sub.2 absorption performance with respect to the separate components that are part of it. These components can be regenerated and reused in several absorption cycles without losing absorption capacity.

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.