Methods for scavenging carbon disulfide (CS.sub.2) from hydrocarbon streams using treatment compositions comprising at least one CS.sub.2 scavenger and at least one phase transfer catalyst therein. The CS.sub.2 scavenger may comprise at least one polyamine with the general formula: H.sub.2N(R.sub.1NH).sub.xR.sub.2(NHR.sub.3).sub.yNH.sub.2 wherein R.sub.1, R.sub.2, R.sub.3 may be the same or different H, aryl or C.sub.1-C.sub.4 alkyl; and x and y may be integers from 0 to 10. A hydrocarbon product with a reduced concentration of CS.sub.2 therein.

Provided is a system for purifying biogas. The system for purifying biogas utilizes a separating unit for methane and carbon dioxide that connects to a separating unit for biogas and a separating unit for carbon dioxide to separate methane and carbon dioxide from the biogas. The separating unit for methane and carbon dioxide may separate the methane and the carbon dioxide. The separating unit for carbon dioxide may separate water and the carbon dioxide. The system for purifying biogas provides high concentration methane for use as fuel for motor vehicles and recycle the water to separate biogas repeatedly.

A system and method of reducing the net carbon dioxide footprint of an industrial process that generates power from the combustion of hydrocarbon fuels in which ambient air is admixed with up to 50% by volume of an effluent gas from the power generator of the industrial process, in order to substantially increase the CO.sub.2 concentration in the air prior to treatment. The treatment comprises adsorbing CO.sub.2 from the admixed ambient air utilizing a cooled, porous substrate-supported amine adsorbent, wherein the porous substrate initially contacts the mixed ambient air containing condensed water in its pores, which act as an intrinsic coolant with respect to the exothermic heat generated by the adsorption process. In addition, prior to regenerating the supported adsorbent, air pressure is substantially reduced in the sealed regeneration chamber and the low pressure chamber is placed in fluid connection with a higher pressure regeneration chamber containing steam and carbon dioxide, to preheat the sorbent to be regenerated and to quickly cool the regenerated sorbent prior to use for further CO.sub.2 adsorption.

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:

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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.

A method and catalysts for increasing the overall mass transfer rate of acid gas scrubbing solids is disclosed. Various catalyst compounds for that purpose are also disclosed.

A carbon dioxide absorbent composition is described, including (i) a liquid, nonaqueous silicon-based material, functionalized with one or more groups that either reversibly react with CO.sub.2 or have a high-affinity for CO.sub.2, and (ii) a hydroxy-containing solvent that is capable of dissolving both the silicon-based material and a reaction product of the silicon-based material and CO.sub.2. The absorbent may be utilized in methods to reduce carbon dioxide in an exhaust gas, and finds particular utility in power plants.

Methods of reducing the water content of a wet gas are presented. In one case, the method includes exposing the gas to an amine-terminated branched polymer solvent to remove a substantial portion of the water from the wet gas, exposing the diluted solvent to carbon dioxide to phase separate the solvent from the water, and regenerating the solvent for reuse by desorbing the carbon dioxide by the application of heat. In another case, the method includes exposing the gas to a cloud-point glycol solvent to remove a substantial portion of the water from the wet gas, heating the diluted solvent to above a cloud point temperature for the solvent so as to create a phase separation of the solvent from the water so as to regenerate the solvent for reuse, and directing the regenerated solvent to a new supply of wet gas for water reduction.

The invention is directed to a germicidal treatment fluid comprising electrolyzed water and an amine, and methods for producing and using same to kill microorganisms which produce hydrogen sulphide or sulphate-reducing bacteria.

Disclosed is an improved process for regenerating solvent used to remove contaminants from a fluid stream. Said process comprises a solvent regeneration system (10) comprising a rich/lean solvent stripper column (29), reboiler (50), condenser (36), and reflux receiver (38) wherein the improvement is the location 46 of the condensed stripper gas return from the reflux receiver.

A process for the removal of CO.sub.2 from flue gases using a co-current flow absorption column followed by one or more serial osmotic filters. The permeate is heated to strip out the CO.sub.2. Both sides of the filters are fed back to the column input.