Abstract: Process for the production of activated carbon, which comprises the stages of carbonizing the starting material and activating the carbonized material. Water and/or carbon dioxide in the supercritical state are employed, as activating agents, in the activation stage of the carbonized material.

Abstract: Microporous carbonaceous materials, useful in the storage of gaseous fuels such as methane and natural gas, are improved through modification of their microporous structure in a post-carbonization process. This modification is done by heat treatment in an oxidizing atmosphere containing carbon dioxide with or without other diluting gases such as nitrogen, argon or water-vapor. The post-carbonization process involved modifying a starting microporous carbon with heat treatment in which the carbon is contacted with a carbon dioxide-containing atmosphere. This new treatment can be favorably applied either to selected and commercially available activated microporous carbons which have been designed for applications other than fuel gas storage or to synthetic microporous carbons proposed for storage of light gases.

Abstract: A method of processing spent ion-exchange resins contaminated with suspended particles, inorganic residues and/or organic foreign matter so as to render the resin ineffective for continued use, by which method this waste material can be processed to produce useful activated carbon particles instead of simply being dumped in a landfill. In accordance with the invention, granular spent organic ion-exchange resin having an ash content of from 5 to 30% is first dried, then carbonized under a substantially inert atmosphere at a temperature of 300 to 900° C., the inert atmosphere containing 0.2 to 4 volume percent oxygen up to 400° C., and finally activated at a temperature of at least 700° C. under a substantially inert atmosphere containing 3 to 50 volume percent steam.

Abstract: PAN-based oxidized fabrics are activated by heating at a temperature of 700-1000.degree. C. for 1 minute to 1 hour with the introduction of moisturized carbon dioxide gas. The resulting PAN-based activated fabrics are suitable for use as adsorption materials.

Abstract: This invention relates to a technique for removing nitrogen oxides (NO.sub.x) present in exhaust gases discharged from boilers and the like. When the temperature of the exhaust gas is 100.degree. C. or below, a heat-treated active carbon produced by heat-treating a raw active carbon at 600 to 1,200.degree. C. in a non-oxidizing atmosphere so as to remove oxygen-containing functional groups present at the surfaces thereof and thereby reduce the atomic surface oxygen/surface carbon ratio to 0.05 or less is preferably used. When the temperature of the exhaust gas exceeds 100.degree. C., a heat-treated active carbon produced by heat-treating a raw active carbon at 600 to 1,200.degree. C. in a non-oxidizing atmosphere and activating the surfaces thereof with sulfuric acid or nitric acid to impart oxidizing oxygen-containing functional groups thereto is preferably used.

Abstract: The present invention relates to carbon and methods for preparing same. In particular, this invention relates to the preparation of novel carbons derived from lignocellulosic materials (particularly wood-based lignocellulosic materials) which are useful for producing high energy density double layer energy storage devices.

Abstract: The present invention relates to carbon and methods for preparing same. In particular, this invention relates to the preparation of novel carbons derived from lignocellulosic materials (particularly wood-based lignocellulosic materials) which are useful for producing high power density double layer energy storage devices.

Abstract: This invention relates to a mesoporous carbon material in the form of filaments having a high surface area. A process is also provided to produce mesoporous carbon material of high surface area. The process comprises drying a carbon material, surface oxidizing the dried material, stabilizing the surface oxidized material, and activating the stabilized material to produce a highly activated, mesoporous material.

Abstract: The present invention discloses an adsorbent comprising a densified carbon black. The densified carbon black comprising the adsorbent preferably has an increase in density of from about 100% to about 500% above the undensified form of the adsorbent. The densified carbon black adsorbent has an increase in adsorption capacity per unit volume over the undensified form of the adsorbent in excess of 100%. The densified carbon blacks are particularly useful as adsorbents for gases.

Abstract: A method for producing an enhanced adsorbent and/or enhanced catalytic particle and/or for producing a catalytic particle, comprising the steps of: (a) removing an effective amount of air from a closed chamber containing an adsorbent and/or catalytic particle, wherein the resultant chamber pressure is less than one atmosphere; (b) raising the chamber pressure with an inert gas to at least one atmosphere; (c) contacting the particle with an energy beam of sufficient energy for a sufficient time to thereby enhance the adsorbent and/or catalytic properties of the particle and/or produce catalytic properties in the particle. A continuous process directed to step (c) alone is also provided. Also disclosed are adsorbent and/or catalytic particles, methods of contaminant reduction or elimination, including room temperature catalysis, particle binders, apparatuses of the present invention, and methods of increasing the surface area of adsorbent and/or catalytic particles.

Abstract: A metal oxide-carrying activated carbon having an oxidation catalytic activity comprises a treated activated carbon obtained by carbonizing a carbon material, activating the obtained carbon with an activating gas comprising carbon dioxide and water vapor, said activating gas containing not more than 15% by volume of water vapor, and then cooling the activated carbon down to a temperature of not more than 300.degree. C. under the same atmosphere; and, carried thereon, 0.1 to 20% by weight as converted into metal of an oxide of at least one metal selected from the group consisting of iron, chromium, nickel, cobalt, manganese, zinc, copper, magnesium and calcium. A deodorant is obtained by adding 1 to 50 parts by weight of a plastic powder having an average particle diameter of 1 to 50 .mu.m to 100 parts by weight of the above metal oxide-carrying activated carbon. The above.

Abstract: Active carbon having a pore size distribution obtained from a nitrogen adsorption isothermal line such that the volume of pores having a pore diameter of less than 15 .ANG. is at least 0.25 ml/g and constitutes at least 40% of the total volume of pores having a pore diameter of at most 300 .ANG., and the volume of pores having a pore diameter of from 100 to 300 .ANG. constitutes at least 10% of the total volume of pores having a pore diameter of at most 300 .ANG..

Abstract: A high energy density capacitor incorporating a variety of carbon foam electrodes is described. The foams, derived from the pyrolysis of resorcinol-formaldehyde and related polymers, are high density (0.1 g/cc-1.0 g/cc) electrically conductive and have high surface areas (400 m.sup.2 /g-1000 m.sup.2 /g). Capacitances on the order of several tens of farad per gram of electrode are achieved.

Abstract: Treatment of a wet activated carbon with carbon dioxide or with carbon dioxide followed by air results in a carbon having a reduced contact pH. The activated carbon is characterized by a modified contact pH less than about 9.0 and typically between about 7.3 and 9.0. Use of this carbon in a water treatment system eliminates the excessive effluent water pH rise which commonly occurs with activated carbon.

Abstract: An improved process for producing a formed activated coke for simultaneous desulfurization and denitrification, which includes passing a ground coal through a tubular or cylindrical carbonization retort by using a hot gas stream, to subject the coal to preliminary carbonization to obtain a semi-coke, adding a caking agent to the semi-coke and forming the mixture, subjecting the formed material to carbonization to obtain a formed coke, and transferring the formed coke from the top to the bottom of a vertical multi-tubular retort of indirect heating and cooling (cooling is optional) type that includes a distribution section, a heating section, an activation section and a cooling section (the distribution section and the cooling section are optional) arranged in this order (the distribution section is at the top), to activate the formed coke.

Abstract: The present invention is a synthesis, product and process for activated carbon and preferably carbon molecular sieve separation of air to produce a nitrogen product wherein a carbon is partially pyrolyzed, impregnated with a transition metal salt and further pyrolyzed to develop enhanced microporosity. The resulting microporous carbon can then be activated with carbon dioxide or steam and then pore-sized by cracking of hydrocarbons on the carbon to produce a carbon molecular sieve.

Abstract: A muffling and denitrating apparatus capable of lowering a level of noise generated by a combustion engine and reducing a concentration of NOx in exhaust gas of the engine. Sound-damping and denitration are accomplished by a carbon fiber or particle layer arranged in the apparatus. Exhaust sound is adsorbed by carbon fibers or carbon particles, resulting in a sound pressure thereof being reduced. NOx is converted into N.sub.2 and CO.sub.2, to thereby be decreased in concentration. Carbon fibers and/or carbon particles for the carbon fiber or particle layer are preferably treated or modified with nitrogen monoxide gas or a nitric acid solution, resulting in having an increased surface area as large as 80 to 2000 m.sup.2 /g.

Abstract: Natural gas is stored in a closed vessel under a pressure of about 1400 to 4500 kPa using a carbon molecular sieve adsorbent having at least 80% of its particle pore volume as micropores having diameters greater than 0.55 nm and less than 0.65 nm, particularly about 0.6 to 0.65 nm. The capacity of such micropores for methane is at least 110 mL methane per mL of carbon (at 300 psig or 2,169 kPa abs.). The deliverable volume of natural gas from a vessel packed with carbon molecular sieve particles is at least 70 times the volume of the vessel. The deliverable volume is optimized by heating a carbonized polymer in the presence of carbon dioxide to increase the pore volume.

Abstract: A microspherical packing for liquid chromatography, which comprises a porous silicon carbide having numerous through-pores, and a process for producing said microspherical packing.

Abstract: A preparing process of activated carbon includes steps of: combusting scrap tires containing metal wire at 400.degree. C. to 900.degree. C. under the presence of oxygen, carbon dioxide and vapor; reheating the generated combustible gases up to 800.degree. C. to 900.degree. C. by adding a further fuel; causing the exhaust gas to heat-exchange with a water pipe boiler so that the temperature of the exhaust gas downs to 180.degree. C. to 250.degree. C.; and introducing the exhaust having a temperature of 180.degree. C. to 250.degree. C. into an electric dust collector so as to collect activated carbon. The particle size of the thus obtained distributed substantially in a range of 90 to 110 mesh and the CEC (cation exchange capacity) of the activated carbon falls within 30 to 40.

Abstract: An apparatus for producing an active carbon using a carbon-containing material inclusive of an used active carbon as a raw material wherein the carbon-containing raw material is carbonized in a carbonizing unit to produce a carbonized material having electric conductivity and the carbonized material is then activated in an activating treatment unit installed downstream of the carbonizing unit in an atmosphere of steam with a power of electricity induced by electric discharge as well as a function of self-heating of the carbonized material with its own electric resistance are disclosed. The carbonizing unit is constructed in the form of a thermal radiation type batch furnace including an outer wall and a vessel mounted on a firing lattice in the outer wall while a heating chamber is formed therebetween.

Abstract: An adsorption type packing for gas chromatography composed of finely divided carbon particles in whole, and having a ratio of nitrogen gas adsorption at a relative pressure of 0.3 (V.sub.0.3) to nitrogen gas adsorption at a relative pressure of about 1.0 (V.sub.1.0) each in the adsorption isotherm of said packing, V.sub.0.3 /V.sub.1.0, of 0.9 or more and a BET specific surface area of 1,000 to 2,000 m.sup.2 /g; and a process for producing said packing.

Abstract: This invention relates to a production process of formed activated coke for SOx and NOx removal which is employed in treatment systems for various flue gases and the like.The formed activated coke for SOx and NOx removal obtained in accordance with the process of this invention has excellent pressure resistance, abrasion resistance and impact strength and also superb SOx- and NOx-removing ability, so that the coke is suitable for use in moving-bed, SOx and NOx- removing systems.The formed activated coke for SOx and NOx removal can of course show excellent SOx- and NOx-removing effects when employed in conventional SOx- and NOx-removing processes and, moreover, owing to its characteristic high NOx-removing ability, is suited for the removal of NOx from low-SOx flue gas of a fluidized-bed combustion boiler or cogeneration power plant.According to the process of this invention, dried, formed activated coke prepared from coal as a raw material is reacted with SO.sub.3 gas at 100.degree.-300.degree. C.

Abstract: A process of preparing lignite (low rank) coal filter material, suitable for use in lieu of more expensive activated carbon filter materials, is disclosed. The process comprises size reducing Leonardite coal material to a suitable filtering effective size, and thereafter heating the size reduced Leonardite preferably to at least 750.degree. C. in the presence of a flow of an inert gas.

Abstract: A process for producing carbon molecular sieves for the separation of oxygen and nitrogen, whereby finely ground hard coal particles are oxidized with air in a fluidized bed, the coal is then formed after the addition of water and binders and carbonized at temperatures of 800.degree.-900.degree. C., subsequently activated with steam at temperatures of 800.degree.-900.degree. C. and the preliminary product of the low-level activation is treated with carbon splitting hydrocarbons. Starches obtained by reacting agglutinized starches with sulphamates are used as binders.

Abstract: Provided are carbon molecular sieves produced by treating carbonacious materials with plasma. One of their most important uses is adsorbent for pressure swing adsorption processes, which are widely used for the separation of gases on industrial scales. The carbon molecular sieves meet the strong demand in this field where the performance of the adsorbent used governs the efficiency of gas separation.The carbon molecular sieves of the present invention are particularly effective in separating nitrogen gas from air.

Abstract: A method and an apparatus for producing an active carbon using a carbon-containing material inclusive of an used active carbon as a raw material wherein the carbon-containing raw material is carbonized in a carbonizing unit to produce a carbonized material having electric conductivity and the carbonized material is then activated in an activating treatment unit installed downstream of the carbonizing unit in an atmosphere of steam with a power of electricity induced by electric discharge as well as a function of self-heating of the carbonized material with its own electric resistance are disclosed. The carbonizing unit is constructed in the form of a thermal radiation type batch furnace including an outer wall and a vessel mounted on a firing lattice in the outer wall while a heating chamber is formed therebetween.

Abstract: A process is provided for forming activated carbon from coal in the particulate state. The coal is first dried at a temperature sufficiently high to effect removal of moisture therefrom but below the temperature at which contained volatile matter vaporizes. The dried coal is then heated to an elevated temperature in a substantially non-oxidizing atmosphere at substantially atmospheric pressure sufficient to volatilize and remove the contained volatile matter and produce a char thereof and the char thereafter subjected to hydrogenation at an elevated temperature and pressure for a time sufficient to form activated carbon characterized by a BET surface area of at least about 200 m.sup.2 /g and an iodine number of at least about 400.

Abstract: A process is disclosed for treating carbonaceous catalyst with a gaseous halogen or a gaseous halogen compound to increase the catalytic activity and prolong the useful life of the catalyst. The treatment of the catalyst is conducted at temperatures above about 150 degrees C., preferably with the use of an inert gas, which inert gas is flowed through the carbonaceous material, and which inert gas carries the gaseous halogen or the gaseous halogen compound to the carbonaceous material.

Abstract: In an apparatus and process for the activation of carbon from carbon feedstocks by electrical resistance heating in the presence of steam, which comprises preheating particles of the carbon feedstock in a preheater, having the particles descend by gravity into and through a vertical reactor connected to the preheater, introducing steam at the bottom of the reactor so that it moves upward against the downward flow of the particles, passing an electric current through the particles in the reactor, and discharging the activated carbon from the bottom of the reactor, the improvements that comprise feeding the carbon feedstock through the side of the preheater, controlling the electric input, having the reactor project into the preheater, using a knife-gate valve and a discharge-limiting device to control the discharge of the activated carbon, using a carbon feedstock that contains up to about 25% of organic volatiles, maintaining the preheating temperature within a range from about 550.degree. C. to about 750.

Abstract: A product having a positive temperature coefficient of resistance is formed by etching a carbon black at an elevated temperature to remove less crystalline portions and thereby to increase the specific surface area of the carbon black. The resulting carbon black is called porous carbon black. The porous carbon black is blended with a crystalline polymer to form a product having the desired positive temperature coefficient of resistance. Production of a material suitable for use as a resettable fuse is described.

Abstract: A carbonaceous adsorbent to be used for the removal of a pyrogen dissolved in water is disclosed. The adsorbent is obtained by carbonizing porous beads of a cross-linked polymer. This adsorbent is favorably used for the removal of endotoxin in the production of pure water from deionized water resulting from the treatment with ion-exchange resins.

Abstract: A coconut shell char having a high oxygen volumetric capacity is provided by crushing and sizing coconut shells to form granules which are then heated in flowing inert gas at a temperature ramp rate of about 2.degree. to 12.degree. C. per minute to a peak temperature of 775.degree. to 900.degree. C. which is then held so that the total heating time is up to 8 hours and thereafter the granular char is cooled in an inert gas atmosphere. The granular char thus produced is oxygen selective in air separation without further modification to narrow the openings of its micropores and has an oxygen volumetric capacity in excess of 8.0 cc/cc. Further modification of this char is provided by contacting it with an oxidizing atmosphere of carbon dioxide or a mixture of inert gas and carbon dioxide, H.sub.2 O or O.sub.2 at temperatures ranging from 650.degree. to 900.degree. C. until the gasified char has been altered so that its volumetric oxygen capacity is greater than 9.0 cc/cc.

Abstract: A process is provided for making a modified carbon molecular sieve which is suitable for separating gases having different adsorption rates on the sieve. The process involves modifying a starting sieve support having a majority of micropores with an effective pore size of about 4.5 to 8 angstroms, with a two-step process in which the sieve is contacted with two different volatile carbon-containing organic compounds, preferably hydrocarbons, which have different molecular dimensions. The compound used in the first step is larger than that in the second step, so that the pore openings of the micropores of the support are narrowed successively in two distinct steps without filling the micropores themselves. The invention also discloses an improved carbon molecular sieve and the separation of gases, such as oxygen from nitrogen, by the use of this improved adsorbent.

Abstract: In an apparatus and process for the activation of carbon from carbon feedstocks by electrical resistance heating in the presence of steam, which comprises preheating particles of the carbon feedstock in a preheater, having the particles descend by gravity into and through a vertical reactor connected to the preheater, introducing steam at the bottom of the reactor so that it moves upward against the downward flow of the particles, passing an electric current through the particles in the reactor, and discharging the activated carbon from the bottom of the reactor, the improvements that comprise feeding the carbon feedstock through the side of the preheater, controlling the electric input, having the reactor project into the preheater, using a knife-gate valve and a discharge-limiting device to control the discharge of the activated carbon, using a carbon feedstock that contains up to about 25% of organic volatiles, maintaining the preheating temperature within a range from about 550.degree. C. to about 750.

Abstract: Carbon molecular sieves, useful in the separation of air into oxygen and nitrogen, are improved through modification of the micropores of the sieve by contact with the pyrolysis products of a carbon-containing compound in the gaseous state diluted with helium, with or without nitrogen as a part of the diluting gas. Volatile organic compounds, such as trimethylcyclohexane, are used with the diluent gas to narrow the micropore openings of a carbon molecular sieve and increase its kinetic selectivity for oxygen adsorption. Carbon dioxide and helium or argon in the diluent gas are used to open pores available to contacting gases.

Abstract: A process is provided for making a modified carbon molecular sieve which is suitable for separating gases having different adsorption rates on the sieve. The process involves modifying a starting sieve support having a majority of micropores with an effective pore size of about 4.5 to 20 angstroms, with a two-step process in which the sieve is contacted with two different concentrations of a volatile carbon-containing organic compound, preferably a hydrocarbon. The concentration of the carbon-containing compound used in the first step is larger than that in the second step, so that the pore openings of the micropores of the support are narrowed successively in two distinct steps without filling the micropores themselves. The invention also discloses an improved carbon molecular sieve and the separation of gases, such as oxygen from nitrogen, by the use of this improved adsorbent.

Abstract: A process for manufacturing a carbon catalyst for use in NO.sub.x reduction with ammonia catalyzed by active carbons and active cokes is described. The new carbon catalyst exhibits improved catalytic activity and hence a higher yield in NO. In the manufacturing process, a mixture of ground, oxidized hard coal and binders is moulded, carbonized at temperatures between 700.degree. and 900.degree. C., and then activated with steam at a temperature of 800.degree. to 850.degree. C. for 45 to 100 minutes, until a degree of activation of 5 to 15% is obtained.

Abstract: A molecular sieving carbon characterized by (A) having a structure in which a number of spherical carbonaceous particles having a particle diameter of 0.8 to 120 micrometers overlap and coalesce three-dimensionally at random, (B) in which continuous pathways running three-dimensionally at random exist between a number of the carbonaceous particles, (C) in which a number of the carbonaceous particles have each a number of micropores communicating with the pathways existing between the particles, and (D) having a carbon content of at least 85% by weight. The molecular sieving carbon is useful for obtaining, for example, a nitrogen gas, oxygen gas or gaseous mixture enriched with either the nitrogen gas or the oxygen gas from a gaseous mixture containing the nitrogen gas and oxygen gas.

Abstract: A carbonaceous adsorbent to be used for the removal of a pyrogen dissolved in water is disclosed. The adsorbent is obtained by carbonizing porous beads of a cross-linked polymer. This adsorbent is favorably used for the removal of endotoxin in the production of pure water from deionized water resulting from the treatment with ion-exchange resins.

Abstract: The present invention relates to physical chemistry.The material is made as a three-dimensional matrix with a pore volume of from 0.2 to 1.7 cm.sup.3 /g. The matrix is formed by bent layers of carbon of 100-10,000 .ANG. thickness and 100-10000 .ANG. radius of curvature. The true density of the material according to the present invention is 1.80-2.10 g/cm.sup.3, its X-ray density is 2.112-2.236 g/cm.sup.3, the pore size distribution has its maximum within the range of 200-2,000 .ANG..The present invention can be useful in, for example, in the production of catalysts.

Abstract: An activated carbon sorbent in which oxygen has been substantially removed from said carbon by outgassing and said oxygen has been replaced by subsequent reaction of the outgassed carbon with a passivating substance.

Abstract: Carbonaceous adsorbent particles having multimodal pore size, including micropores and macropores, with improved adsorptive and separative properties, are prepared by partial pyrolysis of polysulfonated macroporous precursor resins, said resins being in turn derived from macroporous poly(vinylaromatic) resins. The particles may be further treated by activating with reactive gases or by functionalization.

Abstract: A granulated activated carbon is produced by spherically agglomerating activated carbon powder in an aqueous slurry in the presence of a bridging liquid and a binder. At least about 50% of the carbon powder has a surface area of from about 2800 to about 3500 m.sup.2 /gm, an iodine number of from about 2500 to about 3500 mg/gm, a total pore volume of from about 1.0 to about 2.8 cc/gm, and a bulk density of from about 0.27 to about 0.32 gm/cc. The granules are activated by treatment with steam to provide granules having particle diameters of from about 0.17 to about 0.71 mm, and pore size distribution and adsorptive capacity essentially unchanged from that of the carbon powder. The granules are particularly effective for the treatment of drinking water to reduce the level of undesirable contaminants.

Abstract: A molecular sieving carbon characterized by (A) having a structure in which a number of spherical carbonaceous particles having a particle diameter of 0.8 to 120 micrometers overlap and coalesce three-dimensionally at random, (B) in which continuous pathways running three-dimensionally at random exist between a number of the carbonaceous particles, (C) in which a number of the carbonaceous particles have each a number of micropores communicating with the pathways existing between the particles, and (D) having a carbon content of at least 85% by weight. The molecular sieving carbon is useful for obtaining, for example, a nitrogen gas, oxygen gas or gaseous mixture enriched with either the nitrogen gas or the oxygen gas from a gaseous mixture containing the nitrogen gas and oxygen gas.

Abstract: There is provided a relatively large unitized monolithic catalyst panel especially adapted for use in the exhaust lines or conduits of stationary power plants to remove pollutants from the exhaust, especially those using hydrocarbon fuels as a source of power. The panels are characterized by top, bottom and side frame plates in rectangular relation, front and rear stiffener bars extending between the top and bottom plates, separator plates at intervals and in parallel relation extending between the side frame plates to define a grid, and corrugated thin metal foil layers disposed within and filling the spaces within the frame, which foil has a catalytically active surface formed thereon. These devices are useful in removing such pollutants as NO.sub.X from exhaust gas streams.

Abstract: Process for producing carbon molecular sieves for separating oxygen and nitrogen by treating a carbonaceous product with inert gas and steam in a vibrating oven and further treating said product with benzene at a high temperature in a vibrating oven to thereby narrow the existing pores.

Abstract: A catalyst carrier material formed of titanium dioxide and a method of producing the same, includes a mixture of meta and ortho-titanic acid doped with additives which contribute to the stabilization of the crystalline lattice. The mixture is agglomerated under hydrothermal conditions.

Abstract: A process for manufacturing a carbon molecular sieve having both increased gas adsorption capacity and selectivity, which entails:(a) adding coal tar, coal tar pitch, or a combination thereof to powdered coconut shell charcoal as a binder;(b) pelletizing the mixture and carbonizing the same at about 600.degree.-900.degree.;(c) immersing the pellets in mineral acid solution, thereby sustantially removing soluble ingredients containing alkaline metal compounds therefrom;(d) drying the immersed pellets;(e) adding to the dried pellets a fraction of cresote which is distilled at a temperature of 140.degree. to 260.degree. C., in an amount sufficient to increase both said gas adsorption capacity and selectivity;(f) heating the pellets to about 600.degree.-900.degree. C., for about 10-60 minutes; and(g) cooling the pellets in an inert gas.

Abstract: Gas adsorbent and process for producing same. A zeolitic or silica-alumina adsorbent is heat treated in a carbon atom-containing gas or a gaseous mixture consisting of a carbon atom-containing gas and an inorganic gas at 100.degree. to 700.degree. C. to produce the gas adsorbent. The gas adsorbent has carbon particles ranging in size from about 0.01 to about 10 .mu.m adhering on the surface or in pores thereof.