An object of the present invention is to provide a new form of adsorbent suitable for a motor vehicle canister. An activated carbon fiber sheet satisfies one or two or more of conditions for indices, such as a specific surface area, a pore volume of pores having a given pore diameter, and a sheet density. An embodiment, for example, may have: a specific surface area ranging from 1400 to 2200 m.sup.2/g; a pore volume ranging from 0.20 to 1.20 cm.sup.3/g for pores having pore diameters of more than 0.7 nm and 2.0 nm or less; and a sheet density ranging from 0.030 to 0.200 g/cm.sup.3.

An activated carbon for adsorbing neutral per- and polyfluoroalkyl compounds used in quantitative analysis of neutral per- and polyfluoroalkyl compounds in a water sample includes an activated carbon having a BET specific surface area of 900 m2/g or more for desorbably adsorbing neutral per- and polyfluoroalkyl compounds distributed in a gas phase from the water sample by aerating or bubbling, with an inert gas as a carrier gas, the water sample sealed in a vessel and temperature-controlled to a temperature at which the neutral per- and polyfluoroalkyl compounds can be distributed in a gas phase.

An activated carbon for adsorbing neutral per- and polyfluoroalkyl compounds used in quantitative analysis of neutral per- and polyfluoroalkyl compounds in a water sample includes an activated carbon having a BET specific surface area of 900 m2/g or more for desorbably adsorbing neutral per- and polyfluoroalkyl compounds distributed in a gas phase from the water sample by aerating or bubbling, with an inert gas as a carrier gas, the water sample sealed in a vessel and temperature-controlled to a temperature at which the neutral per- and polyfluoroalkyl compounds can be distributed in a gas phase.

A novel method for producing a porous carbon material which makes it possible to easily produce a porous carbon material having a desired shape. The method includes immersing a carbon-containing material having a desired shape and composed of a compound, alloy or non-equilibrium alloy containing carbon in a metal bath, the metal bath having a solidification point that is lower than a melting point of the carbon-containing material, the metal bath being controlled to a lower temperature than a minimum value of a liquidus temperature within a compositional fluctuation range extending from the carbon-containing material to carbon by decreasing the other non-carbon main components, to thereby selectively elute the other non-carbon main components into the metal bath while maintaining an external shape of the carbon-containing material to give a porous carbon material having microvoids.

A novel method for producing a porous carbon material which makes it possible to easily produce a porous carbon material having a desired shape. The method includes immersing a carbon-containing material having a desired shape and composed of a compound, alloy or non-equilibrium alloy containing carbon in a metal bath, the metal bath having a solidification point that is lower than a melting point of the carbon-containing material, the metal bath being controlled to a lower temperature than a minimum value of a liquidus temperature within a compositional fluctuation range extending from the carbon-containing material to carbon by decreasing the other non-carbon main components, to thereby selectively elute the other non-carbon main components into the metal bath while maintaining an external shape of the carbon-containing material to give a porous carbon material having microvoids.

There is provided an activated carbon having a high total trihalomethane filtration capacity, even in water treatment by passing water at a high superficial velocity (SV). In the activated carbon of the present invention, a pore volume A of pores with a size of 1.0 nm or less, of pore volumes calculated by the QSDFT method, is 0.3 cc/g or more, and a pore volume B of pores with a size of 3.0 nm or more and 3.5 nm or less, of pore volumes calculated by the QSDFT method, is 0.009 cc/g or more.

There is provided an activated carbon having a high total trihalomethane filtration capacity, even in water treatment by passing water at a high superficial velocity (SV). In the activated carbon of the present invention, a pore volume A (cc/g) of pores with a size of 1.0 nm or less, of pore volumes calculated by the QSDFT method, is 0.300 cc/g or more, and elemental vanadium and/or a vanadium compound is contained.

One aspect of the present invention relates to a porous carbon material having a nitrogen content of 0.6 to 2.0% by mass, a G band half-value width of 51 to 60 cm.sup.−1 and an R value of 1.08 to 1.40 measured in a Raman spectrum using a laser having a wavelength of 532 nm, and iodine adsorption performance of 1000 to 1500 mg/g.

An object of the present invention is to provide a new form of adsorbent suitable for a motor vehicle canister. An activated carbon fiber sheet satisfies one or two or more of conditions for indices, such as a specific surface area, a pore volume of pores having a given pore diameter, and a sheet density. An embodiment, for example, may have: a specific surface area ranging from 1400 to 2200 m.sup.2/g; a pore volume ranging from 0.20 to 1.20 cm.sup.3/g for pores having pore diameters of more than 0.7 nm and 2.0 nm or less; and a sheet density ranging from 0.030 to 0.200 g/cm.sup.3.

One aspect of the present invention relates to a porous carbon material having a nitrogen content of 0.6 to 2.0% by mass, a G band half-value width of 51 to 60 cm.sup.1 and an R value of 1.08 to 1.40 measured in a Raman spectrum using a laser having a wavelength of 532 nm, and iodine adsorption performance of 1000 to 1500 mg/g.