The present invention addresses to the use of NaY zeolite with a Si/Al ratio >2.6 as a solid adsorbent in the process of removing H.sub.2S from natural gas through a PSA process. The described adsorbent has the capacity of removing H.sub.2S from natural gas from offshore exploration platforms, enabling in situ regeneration. The experimental development proved the high capacity of capturing H.sub.2S by the NaY zeolite in consecutive cycles of pressurization, adsorption, depressurization and purging. This capture capacity remains at 74.2% of the initial capacity, remaining stable in subsequent cycles. The structure of the material maintained crystallinity above 95% in use, in 15 consecutive cycles, allowing the reuse of the adsorbent for a prolonged period of operation, preventing the solid from being constantly changed, which is quite common in a non-regenerative process.

A gas-separation membrane obtainable from curing a composition comprising one or more curable monomers at least 30 wt % of which are monomer(s) comprising oxyethylene groups, oxypropylene groups and at least two polymerizable groups.

A fluid filter, filtering medium composition, and associated process for removing contaminants from feed and exhaust fluids used in fuel cell electricity generation, laboratories, the semiconductor and other industries to improve performance and extend useful equipment lifetimes and to clean fluids of sulfur compound contaminants, as well as to remove noxious NOx and halogen contaminants from feed and exhaust gases.

A process for hydrotreating a feed stream comprising a biorenewable feedstock is disclosed. The process comprises hydrotreating the feed stream in the presence of a hydrotreating hydrogen stream and a hydrotreating catalyst to provide a hydrotreated stream. The hydrotreated stream is separated into a hydrotreated liquid stream and a hydrotreated gas stream. The hydrotreated liquid stream is subjected to stripping to provide a stripper off-gas stream. At least a portion of the stripper off-gas stream is contacted with a caustic stream to provide a sulfur-lean gas stream and a sulfur-rich caustic stream. The sulfur-rich caustic stream is further treated to provide a treated gas stream.

An adsorbent composition for capturing pollutants includes a porous composition that includes a plurality of ferric oxyhydroxide particles and an additional component in the porous composition. The additional component includes one of copper chloride (CuCl.sub.2), zinc chloride (ZnCl.sub.2), polyvinylpolypyrrolidone, silicon carbide, silicon dioxide, activated carbon or other carbonaceous material, and a combination thereof.

An adsorbent bed, including at least one elementary composite structure that includes adsorbent particles in a polymer matrix, wherein the adsorbent bed has a bed packing, ρ.sub.bed, defined as a volume occupied by the at least one elementary composite structure V.sub.ecs divided by a volume of the adsorbent bed V.sub.bed where ρ.sub.bed is greater than 0.60.

An alkaline aqueous ferric iron salt solution is disclosed. Generally, the alkaline aqueous ferric iron salt solution comprises ferric ions (Fe.sup.3+), potassium ions (K.sup.+), carbonate ions (CO.sub.3.sup.2−), bicarbonate ions (HCO.sub.3.sup.−), hydroxide ions (OH.sup.−), optionally nitrate ions (NO.sub.3.sup.−). Further, a molar ratio of the potassium ions to the ferric ions is generally at least 5.0. The ferric iron is complexed with carbonate, bicarbonate or both to form a water-soluble complex that is anionic in nature and highly soluble in the alkaline aqueous ferric iron salt solution at pH above 8.5, and a pH of the alkaline aqueous ferric iron salt solution is at least 8.5.

The removal of acid gases (e.g., non-carbon dioxide acid gases) using sorbents that include salts in molten form, and related systems and methods, are generally described.

A system for removing undesirable compounds from contaminated air includes a biofilter having an alkaline material introduction system and a fuzzy-logic based controller. A contaminant, such as hydrogen sulfide, is removed from contaminated air by passing the contaminated air through the biofilter.

The invention relates to a gas scrubbing process and plant for purifying raw synthesis gas by physical absorption in methanol. A raw synthesis gas stream which includes hydrogen and carbon monoxide as desired constituents and water and acid gases as undesired constituents is admixed with methanol and subsequently cooled below the freezing point of water. According to the invention a liquid phase including methanol and water is separated from the cooled raw synthesis gas stream. Acid gases are removed from the remaining gaseous phase by physical absorption in methanol at elevated pressure. Separating the water from the raw synthesis gas stream before the absorption of the acid gases prevents larger amounts of water passing into the methanol circuit of the gas scrubbing process. This achieves savings in resources and certain plant parts may be smaller than is customary.