Abstract: A reactor comprising a body made of a heat-resistant material and having an inlet and an outlet for water/moisture gas, having a gas-diffusing member provided in an internal space of the body, and having a platinum coating on an internal wall surface of the body. Hydrogen and oxygen fed from the inlet are diffused by the gas-diffusing member and then come into contact with the platinum coating to enhance reactivity, thereby producing water. A temperature of the reactor is held to be below an ignition temperature of hydrogen or a hydrogen-containing gas. The platinum-coated catalyst layer on the internal wall of the reactor body is formed by treating the surface of the internal wall of the body, cleaning the treated surface, forming a barrier coating of a nonmetallic material of an oxide or nitride on the wall surface, and forming the platinum coating on the barrier coating.

Abstract: Regenerable gas purifier materials are provided capable of reducing the level of contaminants such as oxygen and moisture in a hydride gas stream to parts-per-billion levels or sub-parts-per-billion levels. The purifier materials of this invention comprise a thin layer of one or more reduced forms of a metal oxide coated on the surface of a nonreactive substrate. The thin layer may further contain the completely reduced form of the metal. In one embodiment, the total surface area of the thin layer is less than 100 m2/g.

Abstract: Ammonia for use in the manufacture of a GaN-type compound semiconductor, filled in a charging container 18 such that at least a part of the ammonia is liquid and the liquid phase ammonia has a water concentration determined by a Fourier-transform infrared spectroscopy (FT-IR) of 0.5 vol ppm or less, is introduced in the gaseous state into a reaction chamber 11 housing therein a substrate 1, and a layer comprising a GaN-type compound started from this ammonia is formed on the substrate 1.

Abstract: To provide a method for reducing oxygen and carbon components in high-purity fluoride such as calcium fluoride and barium fluoride (high-purity fluoride is not limited to calcium fluoride and barium fluoride), or in rare-earth fluoride such as ytterbium fluoride and cerium fluoride used for an optical fiber, a coating material, and so on.

Abstract: A method and system for the purification and recycle of impure argon is disclosed. The system and process of the present invention can produce very high purity argon, i.e., about 1 ppb or less of impurities. In one embodiment of the invention, a cryogenic separation apparatus is used to remove the nitrogen, hydrocarbon, and hydrogen impurities from the argon stream. A catalyst bed is then operated at ambient temperature to remove hydrogen, oxygen, and carbon monoxide impurities to provide the purified argon product. Also disclosed is a method to minimize to loss of the purified argon product during regeneration of the catalyst bed.

Abstract: This invention is directed to a method for purifying argon from an impure argon stream. If the oxygen concentration in the impure argon is less than about 10 mole percent of oxygen, the invention is proceeded in the sequential steps of a) removing chlorine from the impure argon stream; b) adding hydrogen to the impure argon stream; c) removing carbon dioxide and water from the impure argon stream; d) removing hydrogen from the impure argon stream; and e) removing nitrogen from the impure argon stream to form a purified argon stream.

Abstract: Method for checking the conversion capacity of a catalytic element for converting ozone where the catalytic element is provided as a vehicle radiator with a catalytic coating and the method of checking uses ozone sensors upstream and downstream of the radiator. The check is only carried out if predetermined enable conditions are satisfied. Only then are the values emitted by the sensors recorded and compared with one another. A variable which represents an uncorrected value for the quality of the conversion capacity is derived from this comparison. This variable is weighted as a function of at least one operating parameter of the vehicle. The weighted variable is compared with a predetermined threshold value, and, if the threshold value is exceeded, it is concluded that the conversion capacity of the radiator is insufficient.

Abstract: The invention relates to mixed phase materials for the preparation of catalytic membranes which exhibit ionic and electronic conduction and which exhibit improved mechanical strength compared to single phase ionic and electronic conducting materials. The mixed phase materials are useful for forming gas impermeable membranes either as dense ceramic membranes or as dense thin films coated onto porous substrates. The membranes and materials of this invention are useful in catalytic membrane reactors in a variety of applications including synthesis gas production. One or more crystalline second phases are present in the mixed phase material at a level sufficient to enhance the mechanical strength of the mixture to provide membranes for practical application in CMRs.

Abstract: A method of separating oxygen using a ceramic membrane unit having one or more ceramic membranes, preferably formed of a mixed conducting ceramic, for instance, a perovskite, capable of conducting both oxygen ions and electrons. Oxygen is separated within the ceramic membrane unit under impetus of compressing an incoming oxygen containing feed. The compressor used in the compression is powered by the work of expansion produced by expanding a process stream composed of at least a portion of the retentate produced in the ceramic membrane unit. Prior to expansion, the process stream is cooled to allow the use of less expensive materials in expanders used in the expansion. As a result, expansion of the process stream alone is insufficient to meet the power requirements involved in the compression. Interstage expansion with reheating is used to make up for the power deficit.

Abstract: Method and apparatus for treating the atmosphere to lower the concentration of pollutants, such as ozone, hydrocarbons, nitrogen oxides, sulfur oxides, carbon monoxide and the like, therein in which ambient air is passed into operative contact with a stationary substrate such as an automobile at rest, a billboard, an air conditioning unit, a transportation tunnel and the like, the stationary substrate having at least one ambient air contacting surface having a pollutant treating composition, such as manganese compounds, copper compounds, platinum group metals and compounds thereof, precious metals, and the like, thereon.

Abstract: The present invention relates to high oxygen ion conducting/oxygen storage (OIC/OS) materials, a catalyst employing the OIC/OS materials, and a method for converting hydrocarbons, carbon monoxide and nitrogen oxides using the catalyst. The OIC/OS materials have significantly higher oxygen storage capacity than that predicted based on Ce content due to the unexpected high and facile redox activity of the added niobium. These materials are further characterized by having a tetragonal crystalline structure under oxidizing conditions (in air) up to about 1,200° C. and a cubic crystalline structure in reducing conditions (5% hydrogen) up to about 1,000° C. for 24 hours. These materials comprise, based upon 100 mole % of the metal component in the material, up to about 95 mole % zirconium, up to about 50 mole % cerium, about 0.5 to about 15 mole % rare earth metal(s), alkaline earth metal(s) or a combination thereof, and about 0.5 to about 15 mole % niobium.

Abstract: A process is provided for producing a nitrogen gas, useful in the petroleum industry, by combusting fuel with air in a “once through”-type boiler and injecting a supplemental fuel, such as natural gas, into the exhaust gas at a location just before a combustion catalyst that promotes the reaction between this supplemental fuel and the residual oxygen present in the exhaust gas. This oxygen-diminished, exhaust gas is then passed through a heat exchanger, where it transfers its heat to the air entering the boiler.

Abstract: The method provides technical nitrogen instead of pure nitrogen in liquid form which has to be heated to be brought in gaseous form for laser cutting. Atmospheric air is compressed and driven through a cascade of high density bundles of hollow membrane fibers to permeate oxygen and air's component gases and yield technical nitrogen, and the pressure of the technical nitrogen is boosted to feed the laser cutting equipment. The method thus improves the laser cutting so as to avoid the drawbacks resulting from use of nitrogen in liquid form obtained by the cryogenic process by using technical nitrogen obtained via the aforesaid hollow fiber membrane technology in an efficient and cost effective manner.

Abstract: Method for treating atmospheric pollutants by contacting the atmosphere with a catalyst composition or adsorptive material coated on the surface of a substrate, preferably a motor vehicle radiator, in which the catalyst composition, preferably including a base metal, precious metal, or salts/oxides thereof, or adsorptive material, preferably including a zeolite, Group IIA alkaline earth metal oxide or carbon, is protected from degradation by harmful contaminants such as solid or aerosol particulates, water, SOx, NOx and water borne salts contained in the atmosphere by a coating of at least one porous protective material and a device useful therefor.

Abstract: Method for cleaning the atmosphere by adsorbing pollutants, e.g., hydrocarbons, ozone, carbon monoxide, nitrogen oxides, sulfur oxides, etc., contained in the atmosphere. The pollutant-containing atmosphere is contacted with an outer surface of a substrate, e.g., radiators, condensers, charge air coolers, transmission coolers, etc., which has been coated with an adsorptive material such as zeolites, molecular sieves, carbon, etc. The coated substrate is protected with an overcoat of at least one porous protective material such as alumina, silica and the like, such that the pollutants will come into contact with the adsorptive material, but harmful contaminants will be prevented from contacting the adsorptive material.

Abstract: The present invention relates to a process for modifying the dispersing properties of organometallic-prestabilized or organometallic-pretreated nanometal colloids by reacting reactive metal-carbon bonds in the protective shell to prepare nanometal colloids having a wide range of solubilities in hydrophilic and hydrophobic media including water, to the colloids thus prepared and their use.

Abstract: A novel compound which can be used in the field of separation and purification of gases is disclosed. The compound can be incorporated into a silica gel incorporating polyazacycloalkane structural units for separating a predetermined gas from a mixture of gases. The mixture of gases is brought into contact with a metallated hybrid gel under conditions which make possible the absorption of the gas to be separated, followed by a phase of desorption of the attached gas, and the recovery of the gas.

Abstract: A process for eliminating oxygen (O2) from a gas that contains nitrogen and carbon dioxide (CO2) is described in which combustion of the gas with a hydrocarbon stream is carried out in at least one catalytic combustion zone (5); at the end of the combustion zone, combustion effluents (line 9) that essentially no longer contain O2, a major portion of CO2, and water, are recovered; said combustion effluents are cooled in at least one heat-exchange zone (10) (4) (11) (12); and the cooled effluents are condensed in at least one condensation zone (13) from where condensed water (line 14) and a gas effluent (line 15) essentially no longer containing oxygen are extracted.

Abstract: This invention is directed to a three-stage process for recovering and purifying a helium gas, and a system for using the three-stage process. The steps comprises a) introducing a gas from a cold spray forming chamber to a particulate removing apparatus to form a particulate-free helium gas, and recycling a first portion of the particulate-free helium gas back to the chamber; b) passing a second portion of the particulate-free helium gas to a first compressor prior to passing a helium gas purification membrane to form a purified helium gas and an exhaust gas, and passing the purified helium gas to mix with the first portion of particulate-free helium gas to the chamber; and c) passing a third portion of the particulate-free helium gas to a liquid separator apparatus to remove water and a receiver to dampen any pulsation to form a liquid-free helium gas, and recycling the liquid-free helium gas to said cold spray forming chamber.

Abstract: A method of separating oxygen from an oxygen containing gas using an ceramic membrane unit having one or more ceramic membranes, preferably formed of a mixed conducting ceramic capable of conducting both oxygen ions and electrons. Oxygen is separated within the ceramic membrane unit under impetus of compressing the incoming feed. Sufficient power for such compression is created through expansion of a process stream composed in part of the retentate with interstage expansion reheating.

Abstract: Oxygen is removed from natural gas by contacting oxygen-containing natural gas with nitric oxide under conditions sufficient to produce nitrogen dioxide.

Abstract: The present invention provides a process and apparatus for treating contaminated gas. A contaminated gas containing volatile organic compounds is continuously introduced into a reactor to allow the gas to contact a metal oxide catalyst and an oxidant for a period of time. The concentration of the volatile organic compounds can be thus reduced. The treated gas is then continuously emitted from the reactor. The concentration of the organic compounds of the emitted gas and/or the concentration of the oxidant are continuously monitored, and the oxidant feeding amount is controlled according to the monitored concentration. By means of the process of the present invention, volatile organic compound-containing waste gas with high humidity can be effectively treated, and the utility rate of the oxidant can be increased.

Abstract: A vehicular atmosphere cleansing system utilizes a regenerative wheel having flow channels extending through the wheel coated with an adsorbant. An atmosphere stream passes through a first position dependent portion of the wheel where VOC's including HC's are adsorbed while a heated atmosphere stream passes through a second position dependent regenerative portion of the wheel whereat VOC's are desorbed. The adsorbant is activated carbon having particles of micropore size adhered to the substrate by a silicone binder producing high adsorption efficiencies while withstanding relatively high regenerative heat temperatures resulting from exhaust gas sensible heat. A hydrocarbon senses HC in the desorbed heated atmosphere stream to rotatively and sequentially index pie shaped, segmented portions of the wheel into the wheel's regenerative region while also functioning as the main component of an OBD device for the system.

Abstract: Oxygen is removed from natural gas by contacting oxygen-containing natural gas with nitric oxide under conditions sufficient to produce nitrogen dioxide.

Abstract: A method for treating an effluent gas from a semiconductor processing system includes the steps of exhausting the effluent gas from a processing chamber, and catalytically treating the effluent gas with the at least one mixed metal oxide. The effluent gas includes unconsumed process gasses introduced during semiconductor processing operations, such as during chemical vapor deposition (CVD) and plasma-reactive ion etching. The mixed metal oxide may include a hetero bi-metal oxide, a hetero tri-metal oxide, or a perovskite. A hetero bi-metal oxide includes LaCoO3 and LaMnO3, for example, and a hetero tri-metal oxide includes (LaxPr1−x)CoO3 and (LaxPr1−x)MnO3, for example. The effluent gas may include at least carbon monoxide and/or ozone. Thus, catalytically treating the effluent gas preferably includes the catalytically converting carbon monoxide to carbon dioxide and/or ozone to oxygen.

Abstract: This invention is directed to a method for purifying argon from an impure argon stream. If the oxygen concentration in the impure argon is less than about 10 mole percent of oxygen, the invention is proceeded in the sequential steps of a) removing chlorine from the impure argon stream; b) adding hydrogen to the impure argon stream; c) removing carbon dioxide and water from the impure argon stream; d) removing hydrogen from the impure argon stream; and e) removing nitrogen from the impure argon stream to form a purified argon stream.

Abstract: An oxygen-absorbing composition containing particulate annealed electrolytically reduced iron of between about 100 mesh and 325 mesh in an amount of about up to 63% by weight, a salt such as sodium chloride in an amount by weight of about up to 3.5%, and a water-supplying component comprising activated carbon. with liquid water therein of a mesh size of between about 20 mesh and 50 mesh in an amount by weight of up to about 85% in an envelope which will resist the passage of liquid water out of the envelope but will permit flow of oxygen into the envelope at a satisfactory rate.

Abstract: The present invention provides for novel solid state O2-selective metal complex-based adsorbents and their utility for separating oxygen from a gas stream. In particular, the invention provides for an adsorption complex which contains four-coordinate O2-selective metal complexes including oligomeric/polymeric metal complexes, and organic base-containing polymers supported on porous materials.

Abstract: An oxygen generator of an emergency chemical oxygen generating system is mounted on a sliding mechanism that displaces the oxygen generator vertically and horizontally away from the walls of the oxygen generator container when the door of the module is opened, in order to reduce the heating of the container walls and the surrounding areas. The sliding mechanism can be a telescoping assembly having multiple sliding segments, a slot in the side of the module wall with a tab attached to the generator such that the tab slides within the slot allowing for downward sliding of the generator, or an arrangement of channels and rollers. The movement of the generator from a stowed position to a use position can also initiate the flow of oxygen.

Abstract: Method for treating atmospheric pollutants by contacting the atmosphere with a catalyst composition or adsorptive material coated on the surface of a substrate in which the catalyst composition or adsorptive material is protected from degradation by harmful contaminants contained in the atmosphere by a coating of at least one porous protective material and a device useful therefor.

Abstract: A method is provided for performing catalytic or non-catalytic processes which uses oxygen supplied from the permeate side of a mixed oxygen ion and electron conducting membrane by means of a sweep gas at an elevated temperature. The sweep gas is formed by burning fuel in a sweep gas preheater. The sweep gas containing oxygen picked up from the membrane is reacted with a hydrocarbon fuel in a catalytic reactor to form a syngas containing nitrogen and hydrogen. The nitrogen and hydrogen containing syngas is worked up into ammonia; the ammonia is burned in an ammonia burner to produce a nitrogen oxides containing gas, and the nitrogen oxides containing gas is used in the production of nitric acid. The process is able to directly transfer the oxygen containing sweep gas to the catalytic reactor, without any intermediate cooling; recompression and reheating.

Abstract: A method for cleaning exhaust air containing pollutants, especially gaseous hydrocarbon emissions in an exhaust duct, using a catalyst and a UV radiation raising the energy level of the hydrocarbons, in which the exhaust air is exposed in a first section of the air duct to UV-C radiation of a wavelength of below 300 nm, preferably of about 254 nm, which causes an excitation of the hydrocarbons to higher energy levels, and also to a UV-C radiation of a wavelength preferably of about 185 nm, which additionally causes the formation of ozone, and of molecular oxygen and radicals from the ozone, while a partial oxidation of the hydrocarbon molecules takes place in the gas phase, and in that in a following second section of the air duct a catalytic oxidation of the hydrocarbon molecules is performed at the inner surface of a porous support material, the hydrocarbon molecules being absorbed, then oxidized on the active surface by the additionally formed ozone and removed from the surface of the catalyst in the form

Abstract: The present invention is a waste water treatment system, which includes at least one closed, covered structure having waste water ingress and waste water egress and waste water treatment capabilities within the structure, and having an ambient air ingress with predetermined volumetric air flow rates, and having an ambient air egress for release of air to the atmosphere; and further includes an ionic oxygen generator connected to the air ingress or egress and has sufficient capacity to generate at least 200 ions of ionic oxygen for removal of odor from exiting air before it is released to the atmosphere. In some preferred embodiments, the waste water treatment is a dissolved air flotation treatment with at least one covered tank containing solid-liquid waste content, and includes sufficient pumping capacity to floatate a solid component of the solid-liquid waste content of the tank.

Abstract: There are disclosed a process for purifying ammonia which comprises bringing crude ammonia into contact with a catalyst comprising manganese oxide as an effective ingredient to remove oxygen and/or carbon dioxide that are contained as impurities in the ammonia, and a process for purifying ammonia which comprises bringing crude ammonia into contact with a catalyst comprising manganese oxide as an effective ingredient, and thereafter with a synthetic zeolite having a pore diameter in the range of 4 to 10 Å to remove at least one impurity selected from the group consisting of oxygen, carbon dioxide and moisture that are contained in the crude ammonia. It is made possible by the above process to remove impurities to an extremely low concentration from crude ammonia available on the market for industrial use and crude ammonia from a gallium nitride compound semi- conductor without decomposition of ammonia to generate hydrogen.

Abstract: An inert gas production system which primarily employs the exhaust gas of an engine as an inert gas source and uses a catalytic purifier to remove oxygen from the engine exhaust to produce the inert gas. The engine is preferably an internal combustion engine which operates on methane. The catalytic purification of the exhaust gas to remove oxygen is preferably performed by a packed bed catalytic purifying system including two catalyst vessels operated in series. The inert gas production system using engine exhaust can operate at a lower cost than the known membrane purification systems which produce an inert gas from air. In addition, the engine can be connected to a generator to provide an electrical energy advantage and the entire system can produce an inert gas stream containing less than 1,000 ppm of oxygen.

Abstract: Method and apparatus for treating the atmosphere to lower the concentration of pollutants therein in which ambient air is passed into operative contact with a stationary substrate having at least one ambient air contacting surface having a pollutant treating material thereon.

Abstract: Method for treating atmospheric pollutants by contacting the atmosphere with a catalyst composition or adsorptive material coated on the surface of a substrate in which the catalyst composition or adsorptive material is protected from degradation by harmful contaminants contained in the atmosphere by a coating of at least one porous protective material and a device useful therefor.

Abstract: A reductant injection control strategy for controlling an amount of nitrogen oxide reducing agent injected upstream of a selective reduction catalyst uses an ammonia sensor located downstream of the catalyst. An open loop injection quantity is first determined based on operation conditions. Ammonia concentration detected downstream of the catalyst is controlled to a desired value, with the desired value based on catalyst temperature and the open loop injection quantity.

Abstract: A metal hydride getter purifier operated at less than 350° C. to remove impurities such as carbon dioxide, carbon monoxide, nitrogen, oxygen and water to levels of the order of one ppb or less from hydrogen without creating greater than 10 ppb methane. A cryogenic stage after the getter stage may be used to ensure removal of methane from hydrogen.

Abstract: An oxygen-absorbing composition containing particulate annealed electrolytically reduced iron of between about 100 mesh and 325 mesh in an amount of about up to 63% by weight, a salt such as sodium chloride in an amount by weight of about up to 3.5%, and a water-supplying component comprising activated carbon with liquid water therein of a mesh size of between about 20 mesh and 50 mesh in an amount by weight of up to about 85% in an envelope which will resist the passage of liquid water out of the envelope but will permit flow of oxygen into the envelope at a satisfactory rate.

Abstract: A process and apparatus for the decontamination of gaseous contaminants (especially oxygen, carbon dioxide and water vapor) from hydride gases (including their lower alkyl analogs) down to ≦100 ppb contaminant concentration are described. The critical component is a high surface area metal oxide substrate with reduced metal active sites, which in various physical forms is capable of decontaminating such gases to ≦100 ppb, ≦50 ppb or ≦10 ppb level without being detrimentally affected by the hydride gases. The surface area of the substrate will be ≧100 m2/g, and preferably 200-800 m2/g. Oxides of various metals, especially manganese or molybdenum, can be used, and mixtures of integrated oxides, or one type of oxide coated on another, may be used. The substrate is preferably retained in a hydride-gas-resistant container which is installed in a gas supply line, such as to a gas- or vapor-deposition manufacturing unit.

Abstract: An assembly, a method and a motor vehicle for cleaning ambient air in the vicinity of an internal combustion engine (102) having combustion air inlet means (103) and energy emitting means (104)are disclosed. The assembly (101) further includes adsorbent means (105) for adsorbing at least one pollutant when in a first mode of operation and for desorbing the pollutant when in a second mode of operation. The adsorbent means have an inlet (106) for polluted ambient air (107, 107′) and an outlet (108) for cleaned ambient air (109, 109′). Furthermore, the assembly (101) includes a pollutant conduit (110) through which the desorbed pollutant is transferred from the adsorbent means (105) to the combustion air inlet means (103) when in the second mode of operation, and the adsorbent means (105) are arranged for being brought into the second mode of operation by means of energy supplied from the energy emitting means (104).

Abstract: Method and apparatus for treating the atmosphere to lower the concentration of pollutants therein in which ambient air is passed into operative contact with a stationary substrate having at least one ambient air contacting surface having a pollutant treating material thereon.

Abstract: An improved catalytic converter which comprises a metal monolith made of aluminum or aluminum alloy having an anodized surface layer on which is disposed catalytic metals, particularly noble metals from Group VIII and optionally base metals. In a preferred embodiment the metal monolith employs plate fin elements defining a large plurality of fins arranged in an axial succession of offset fin rows. The catalytic converter has application in the conversion of ozone and the oxidation of atmospheric pollutants.

Abstract: Method and apparatus for treating the atmosphere to lower the concentration of pollutants therein in which ambient air is passed into operative contact with a stationary substrate such as an automobile at rest, a billboard, an air conditioning unit, a transportation tunnel and the like, the stationary substrate having at least one ambient air contacting surface having a pollutant treating composition thereon.

Abstract: Method for treating atmospheric pollutants by contacting the atmosphere with a catalyst composition or adsorptive material coated on the surface of a substrate in which the catalyst composition or adsorptive material is protected from degradation by harmful contaminants contained in the atmosphere by a coating of at least one porous protective material and a device useful therefor.

Abstract: The invention is directed to a process for the separation of oxygen from an oxygen containing gas using an oxygen selective material comprising a transition element complex comprising a first transition element ion and one or more chelating ligands, wherein: i) said first transition element ion is capable of accepting intermolecular donation; ii) said chelating ligand or ligands provides up to four intramolecular donor sites to said transition element ion; iii) said chelating ligand or ligands provides an intermolecular donor site to a second transition element ion which is contained in second discrete transition element complex; and iv) said chelating ligand or ligands contains at least one substituent that inhibits &mgr;-peroxo dimer formation on said sorbent; wherein when said material is in deoxy form, the total number of donor sites to said first transition element ion is five.

Abstract: A process for recovering carbon dioxide from a gas containing both carbon dioxide and oxygen wherein a carbon dioxide and oxygen containing gas is first contacted with an alkanolamine solution to produce an alkanolamine loaded with carbon dioxide and oxygen, the oxygen is separated from the absorption solution, such as by stripping with a scavenging gas, such as the carbon dioxide containing fluid obtained from the separation of carbon dioxide from the alkanolamine solution or nitrogen, prior to any heating of the absorption solution, and carbon dioxide is steam stripped from the absorption solution and recovered. By stripping the oxygen out of the alkanolamine solution, oxidative degradation of the alkanolamine can be reduced.

Abstract: The invention relates to polyazacycloalkanes having 3, 4 or 5 nitrogen atoms, tri-, tetra- or penta-azamacrocyclic transition metal complexes and processes for the production of said polyazacycloalkanes. The object of the invention is to form polyazacycloalkanes able to trap metal cations and in particular U, Pu, Am, Ce, Eu, Al, Gd, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ag, Cd, Sn, Au, Mg or Pb or complexes able to trap in particular oxygen in a gaseous mixture. The invention more particularly applies to the treatment of liquid effluents from nuclear power stations.

Abstract: An exhaust gas purifying catalyst for use in an oxygen surplus atmosphere, includes a brown millerite composite oxide for directly decomposing and absorbing nitrogen oxide (NOx), and a noble metal-series reducing catalyst disposed on the surface of said brown millerite composite oxide. The brown millerite composite oxide is represented by one of the following formulae: A3-aBaC4-bDbO9, A2-aBaC2-bDbO5, and A1-aBaC2-bDbO4 where A and B are elements selected from the group consisting of Ba, Ca, Sr, Mg and Ce, C and D are elements selected from the group consisting of Y, Dy, Zn, Ti, Mn, Fe, Co, Ni, Cu, Sn, Zr and Nd, a is within the range 0≦a<1, and b is within the range 0≦b<2.