CN118043546A

CN118043546A - Molded adsorbent for adsorption tank

Info

Publication number: CN118043546A
Application number: CN202280065572.0A
Authority: CN
Inventors: 渡边佳英; 今井大介; 高田由生; 柳栋曣
Original assignee: Nippon Paper Industries Co Ltd
Current assignee: Nippon Paper Industries Co Ltd
Priority date: 2021-09-29
Filing date: 2022-09-21
Publication date: 2024-05-14

Abstract

An object of the present invention is to provide an adsorbent which is suitable for an adsorption tank and in which pressure loss is suppressed. A further object to be solved is to provide a molded adsorbent which is a molded article that is less likely to collapse in shape even when activated carbon fibers are used and which exhibits excellent effects as an adsorbent for an adsorption tank. The molded adsorbent for the canister satisfies at least the following requirements (A), (B) and (C). (A) The molded adsorbent is a molded article comprising activated carbon fibers, granular activated carbon, and a binder. (B) The weight ratio of the activated carbon fiber to the granular activated carbon is 5 to 95 parts by weight of the activated carbon fiber and 95 to 5 parts by weight of the granular activated carbon in the total amount of the activated carbon fiber and the granular activated carbon. (C) The binder in the molded adsorbent is present in an amount of 0.3 to 20 parts by weight based on 100 parts by weight of the active carbon fibers and the granular active carbon.

Description

Molded adsorbent for adsorption tank

Technical Field

The present invention relates to a molded adsorbent for an adsorption tank, and more particularly, to a molded adsorbent for an adsorption tank using activated carbon.

Background

In vehicles such as automobiles, motorcycles (motor bicycles), and boats, in which an internal combustion engine for burning a vaporized fuel such as gasoline is mounted, the pressure in a fuel tank fluctuates due to a change in the outside air temperature, and the vaporized fuel gas filled in the fuel tank is released from the fuel tank. The emitted vaporized fuel gas is one of the causative substances of PM2.5 and photochemical smog, and an adsorption tank (also referred to as a vaporized fuel suppressing device) provided with an adsorbent such as activated carbon is provided to prevent the release of the vaporized fuel gas into the atmosphere.

With recent increases in environmental conservation consciousness, emission restrictions on various gases tend to be strengthened year by year, and therefore, higher adsorption performance is also required for the canister. Further, since the air intake capability of automobiles tends to be suppressed due to the popularization of idle stop and the like, there is a tendency that the gasoline adsorbed to the adsorbent in the canister is difficult to desorb. Therefore, further improvement in performance of the adsorbent used for the canister is demanded. As an adsorbent for an adsorption tank, activated carbon is often used, and as its shape, an adsorbent molded into a granular, pellet or honeycomb shape has been proposed (for example, patent document 1).

In recent years, from the viewpoint of improving the performance of the canister, a main chamber, a sub chamber, and the like are provided, and the adsorbent is stored in a plurality of chambers (for example, patent document 2).

In contrast to the powdered or granular activated carbon which has been known from the past, activated carbon fibers (or fibrous activated carbon) are sometimes called tertiary activated carbon. In the broad sense of activated carbon, activated carbon fibers are believed to have the following tendencies: the micro-holes are directly opened on the outer surface, so that the adsorption and desorption speed is high. However, activated carbon fibers have not been put to practical use as adsorption tanks, and studies and developments have not been made sufficiently as to what characteristics of activated carbon fibers are suitable for practical use as adsorption tanks.

As one of the adsorbent materials suitable for the adsorption tank, an activated carbon fiber sheet having predetermined characteristics is proposed (patent document 3).

In order to improve the mechanical strength and packing density of a molded adsorbent using activated carbon fibers, an activated carbon fiber molded adsorbent comprising activated carbon fibers and fibrillated cellulose fibers having alkali resistance has been proposed (for example, patent document 4). Prior art literature

Patent literature

Patent document 1: japanese patent laid-open No. 2013-173137

Patent document 2: japanese patent application laid-open No. 2019-10880

Patent document 3: japanese patent No. 6568328

Patent document 4: japanese patent laid-open No. 10-5580

Disclosure of Invention

Problems to be solved by the invention

As described above, an attempt has been made to use activated carbon fibers as an adsorbent for an adsorption tank, but there is room for development of activated carbon fibers as an adsorbent for an adsorption tank. In addition, when the main chamber, the sub chamber, and the like are filled with the adsorbent in the plurality of storage chambers, there is room for development as to what adsorbent should be used.

The present inventors have conducted intensive studies with the object of practically using activated carbon fibers as an adsorbent for an automobile canister, and as a result, have found that a sheet made of activated carbon fibers is a practically preferable embodiment from the viewpoint of easiness in fixing and handling such that the adsorbent is not worn out by vibration or the like during running of an automobile. However, if the activated carbon fiber sheet obtained by carbonizing and activating the same as in the prior art is filled into the room for accommodating the adsorbent without providing any gap, there is a new problem that the pressure loss of the canister increases.

In view of the above, one of the problems to be solved is to provide an adsorbent using activated carbon fibers, which is suitable for canister applications and can suppress pressure loss.

Another object of the present invention is to provide a molded adsorbent which is a molded article that is less likely to collapse in shape despite the use of activated carbon fibers and which exhibits excellent effects as an adsorbent for an adsorption tank.

Means for solving the problems

The inventors of the present application have made intensive studies to solve the above problems, and studied on a molded body of activated carbon fiber as one of the directivities. Then, molded articles having various properties required for canister use were successfully produced using activated carbon fibers and a binder. The inventors of the present application have found that by mixing and molding activated carbon fibers with activated carbon in a different form such as granular activated carbon, the pressure loss can be further reduced as compared with a molded product using either activated carbon fibers or granular activated carbon and a binder.

The invention proposed in the present invention can be understood from various aspects as several aspects, and as a result, means for solving the problems include, for example, the following embodiments. (the invention proposed in the present invention is also referred to as "invention")

A molded adsorbent for an adsorption tank,

The molded adsorbent comprises activated carbon fibers, granular activated carbon and a binder,

The weight ratio of the activated carbon fiber to the granular activated carbon is 5 to 95 parts by weight of the activated carbon fiber to 95 to 5 parts by weight of the granular activated carbon,

The binder in the molded adsorbent is present in an amount of 0.3 to 20 parts by weight based on 100 parts by weight of the active carbon fibers and the granular active carbon.

The molded adsorbent according to item [ 2 ] above, wherein the pressure loss of the molded adsorbent is smaller than the pressure loss of the molded article of the mixture of the activated carbon fiber and the binder and the pressure loss of the molded article of the mixture of the granular activated carbon and the binder.

The molded adsorbent for a canister according to the above [2 ], wherein the pressure loss of the molded adsorbent is 0.52kPa or less.

The molded adsorbent for a canister according to the above [2 ], wherein the pressure loss of the molded adsorbent is 0.45kPa or less.

The molded adsorbent according to any one of the above [1 ] to [ 4], wherein the granular activated carbon has an average particle diameter of 100 to 3000. Mu.m.

The molded adsorbent according to any one of the above [1 ] to [ 5 ], wherein the activated carbon fibers have an average fiber length of 300 to 10000. Mu.m.

The molded adsorbent according to any one of the above [1 ] to [ 6 ], wherein the molded adsorbent has a dry density of 0.010 to 0.400g/cm ³.

The molded adsorbent according to any one of [1 ] to [ 7 ], wherein the molded adsorbent has a specific surface area of 2500m ²/g or less.

The molded adsorbent according to any one of the above [1 ] to [ 8 ], wherein the molded adsorbent has a total pore volume of 0.50 to 1.20cm ³.

The molded adsorbent according to [1 ] to [ 9 ], wherein the binder is a fibrous binder.

The molded adsorbent as described in [ 1], wherein the granular activated carbon has an average particle diameter of 100 to 3000. Mu.m,

The average fiber length of the activated carbon fibers is 300 to 10000 mu m,

The drying density of the formed adsorbent is 0.010-0.400 g/cm ³,

The specific surface area of the molded adsorbent is 2500m ²/g or less,

The total pore volume of the molded adsorbent is 0.50-1.20 cm ³, and

The binder is a fibrous binder.

The molded adsorbent as described in [3 ], wherein the granular activated carbon has an average particle diameter of 100 to 3000. Mu.m,

The average fiber length of the activated carbon fibers is 300 to 10000 mu m,

The drying density of the formed adsorbent is 0.010-0.400 g/cm ³,

The specific surface area of the molded adsorbent is 2500m ²/g or less,

The total pore volume of the molded adsorbent is 0.50-1.20 cm ³, and

The binder is a fibrous binder.

[ 13 ] An adsorption tank comprising the molded adsorbent according to any one of [ 1 ] to [ 12 ].

Effects of the invention

According to one or more aspects of the present invention, an adsorbent using activated carbon fibers, which is suitable for canister use, and which suppresses pressure loss, can be provided.

Further, according to one or more aspects of the present invention, a molded adsorbent which is a molded article having a shape less prone to collapse despite the use of activated carbon fibers and which exhibits excellent effects as an adsorbent for an adsorption tank can be provided.

Drawings

Fig. 1 is a view schematically showing an example of a layered adsorbent in which a plurality of sheet-shaped molded adsorbents are layered, and an example of a flow direction of a fluid passing through the layered adsorbent.

FIG. 2 is a view showing an example of a disc-shaped adsorbent.

FIG. 3 is a view showing an example of a cylindrical adsorbent.

Detailed Description

The invention is an international application based on patent cooperation treaty, and the language of the application is Japanese. The present invention, when transferred to a designated country and a selected country, is intended to translate into a language required by each country. In the present invention, nouns in japanese may be singular or plural, depending on the context or the full text of the invention, unless otherwise indicated. In addition, when a noun is translated into a language having a distinction of singular or plural numbers among a countable noun, an inexhaustible noun, and a countable noun, as in the english language, etc., unless otherwise specified, the expression of the singular includes the plural number, and the expression of the plural number includes the singular number, depending on the context or the whole of the present invention.

Hereinafter, embodiments of the present invention will be described. The embodiments shown below provide specific description for easy understanding of the present invention, but the present invention is not limited to the embodiments shown below, and each component and their combination may be appropriately modified within a range not departing from the gist of the present invention. In addition, hereinafter, embodiments of the present invention are sometimes described with reference to the drawings. The shapes, sizes, arrangements, and the like of the constituent elements in the drawings are schematically shown for easy understanding of the present invention, and may be appropriately changed within a range not departing from the gist of the present invention. In the drawings, the same components are denoted by the same reference numerals, and overlapping description may be omitted.

In the present invention, unless otherwise specified, the term "AA to BB" refers to "AA or more and BB or less" in terms of the numerical range (here, "AA" and "BB" refer to arbitrary numerical values). In addition, as for the units of the lower limit and the upper limit, unless otherwise specified, both are the same as the unit immediately after the latter (i.e., herein, "BB"). In the present invention, the combination of the lower limit value and the upper limit value of the numerical range may be arbitrarily selected from a numerical group of the lower limit value or the upper limit value described as an example of preferable numerical values. In addition, the expression "X and/or Y" means both or either of X and Y.

In the description of the present invention, unless otherwise specified, the term "pore diameter" refers not to the radius of pores but to the diameter or width of pores.

1. Molded adsorbent for adsorption tank

In one embodiment of the invention, the shaped adsorbent body can be suitably used in an adsorption tank. The canister is provided with an adsorbent, and serves to adsorb vaporized fuel vapor to the adsorbent and suppress the release of the fuel vapor to the atmosphere, or to desorb fuel vapor adsorbed to the adsorbent and supply the fuel vapor to the engine when the engine is operated. The canister is generally used for machines and devices including an internal combustion engine using a fuel containing highly volatile hydrocarbons, such as a vehicle and a ship equipped with the internal combustion engine. Examples of the vehicle include a gasoline-fueled automobile and the like. Examples of the vessel include a vessel that is fuelled with gasoline.

In one embodiment of the present invention, the shaped adsorbent comprises activated carbon fibers, granular activated carbon, and a binder. In a preferred embodiment, the molded article may be a mixture of activated carbon fiber, granular activated carbon, and a binder. In another preferred embodiment of the molded adsorbent, a laminate structure may be formed by bonding a plurality of sheets having powdered activated carbon attached to or held on the surface of an activated carbon fiber sheet with a binder.

In one embodiment of the present invention, the weight ratio of the activated carbon fiber to the granular activated carbon is 5 to 95 parts by weight of the activated carbon fiber and 95 to 5 parts by weight of the granular activated carbon in the total amount of the activated carbon fiber and the granular activated carbon. In other words, the content of the activated carbon fiber and the granular activated carbon contained in the molded adsorbent is preferably 5 to 95 parts by weight, and more preferably 5 to 95 parts by weight of the granular activated carbon per 100 parts by weight. An example of specifically determining the numerical value is shown. In the case of a molded adsorbent having a total content of activated carbon fibers and granular activated carbon of 10g, for example, one embodiment or the like may be used in which 5g (50 parts by weight) of activated carbon fibers and 5g (50 parts by weight) of granular activated carbon are contained.

Although it varies depending on the performance required for the molded adsorbent, for example, from the viewpoint of reducing the pressure loss, the weight ratio of the activated carbon fiber to the granular activated carbon (activated carbon fiber: granular activated carbon) may be preferably 95 to 5 parts by weight: 5 to 95 weight portions.

The contents of the activated carbon fiber and the granular activated carbon are described below, respectively, from the viewpoint of reducing the pressure loss.

The upper limit of the content of the activated carbon fibers in the molded adsorbent may be preferably 95 parts by weight or less, more preferably 75 or 65 parts by weight or less, and still more preferably 55 or 45 parts by weight or less per 100 parts by weight of the total weight of the activated carbon fibers and the granular activated carbon. The lower limit of the content of the activated carbon fibers in the molded adsorbent may be preferably 5 or 8 parts by weight or more per 100 parts by weight of the total weight of the activated carbon fibers and the granular activated carbon.

On the other hand, the upper limit of the content of the granular activated carbon in the molded adsorbent may be preferably 95 or 92 parts by weight or less per 100 parts by weight of the total weight of the activated carbon fibers and the granular activated carbon. The lower limit of the content of the granular activated carbon in the molded adsorbent may be preferably 5 parts by weight or more, more preferably 25 or 35 parts by weight or more, and still more preferably 45 or 55 parts by weight or more, per 100 parts by weight of the total weight of the activated carbon fibers and the granular activated carbon.

As described above, in one embodiment of the present invention, activated carbon fibers and granular activated carbon are used as one component constituting the molded adsorbent. Various embodiments of activated carbon fibers and granular activated carbon are described in more detail below.

In one embodiment of the present invention, a binder is used as one component constituting the molded adsorbent. The binder that can be used is preferably a binder that does not easily clog the activated carbon fibers and the pores of the activated carbon, and examples of the material include polyvinyl alcohol. Further, as a preferable example of the binder, a fibrous binder can be given. The fibrous binder is not particularly limited as long as it can be formed by interlacing activated carbon fibers and granular activated carbon by fibrillation. Can be widely used both as a synthetic product and a natural product. Examples of such fibrous binders include acrylic fibers, polyethylene fibers, polypropylene fibers, polyacrylonitrile fibers, cellulose fibers, nylon fibers, and aramid fibers.

In one embodiment of the present invention, the binder may be contained in the molded adsorbent in an amount of 0.3 to 20 parts by weight based on 100 parts by weight of the content of the activated carbon fibers and the granular activated carbon. More specifically, as described below.

The lower limit of the content ratio of the binder may be preferably 0.3, 0.5, 0.8, 1.0, 2.0, or 3.0 parts by weight.

The upper limit of the content ratio of the binder may preferably be 20, 18, 15, or 10 parts by weight.

Examples of specifically determining the numerical values are shown. For example, in the case of a molded adsorbent having a total content of activated carbon fibers and granular activated carbon of 10g, 0.03g to 2g of a binder may be added. In this case, therefore, the total weight of the activated carbon fiber, the granular activated carbon, and the binder in the molded article is 10.03g to 10.2g.

The binder is blended in the above-described content ratio, whereby the molded adsorbent can be produced with both mechanical strength and adsorption/desorption performance. If the mechanical strength is to be further improved, the amount of the binder can be increased, and if the adsorption/desorption performance is to be more emphasized, the amount of the binder can be set to be low. Further, forming such a content is also suitable for obtaining a molded adsorbent having a small pressure loss.

The activated carbon fibers may preferably be mixed in the state of fibers after defibration. By mixing the fiber after defibration with components such as granular activated carbon and binder, the components are entangled as well as possible, and the bonding becomes good, so that the mechanical strength of the molded article can be improved, and the molded article less prone to shape collapse can be produced.

As another embodiment of the present invention, for example, the following embodiment may be exemplified.

A molded adsorbent for an adsorption tank, the molded adsorbent comprising activated carbon fibers, granular activated carbon, and a binder, wherein the pressure loss of the molded adsorbent is smaller than the pressure loss of either one of a molded article of a mixture of the activated carbon fibers and the binder or a molded article of a mixture of the granular activated carbon and the binder.

The molded adsorbent of the present application can be produced into a molded adsorbent having low pressure loss. The activated carbon fiber itself is a material with little pressure loss among several activated carbons. However, when only activated carbon fibers are used, the shape tends to collapse easily. Accordingly, in order to improve the shape stability, the inventors of the present application devised to mix granular activated carbon and a binder in activated carbon fibers and perform molding processing. Initially, although the shape stability is improved by molding, even in a good case, there is a possibility that the average of the molded body formed of the activated carbon fiber and the binder, the granular activated carbon and the binder, or the pressure loss will become large. However, the molded article of the three mixtures can give an unexpected molded adsorbent having a smaller pressure loss than both the molded article of the two mixtures of activated carbon fiber and binder and the molded article of the two mixtures of granular activated carbon and binder.

The mechanism of action is not necessarily clear, but it is considered that the activated carbon fiber and the granular activated carbon are consistent in terms of the activated carbon, but are materials of different properties in terms of physical properties such as shape, so that voids are generated by the mixed state of the materials of different properties and act in a direction of reducing pressure loss.

In one embodiment of the present invention, the pressure loss may be preferably 0.05 to 0.52kPa. More specifically, as described below.

In one embodiment of the present invention, the upper limit of the pressure loss of the molded adsorbent may be preferably 0.52, 0.50, 0.45, or 0.43kPa or less, more preferably 0.40, 0.38, 0.35, or 0.33kPa or less, and still more preferably 0.30, 0.28, or 0.25kPa or less.

The lower the pressure loss is, the more preferable, and the lower limit of the pressure loss is preferably 0.05kPa, 0.08, or 0.10kPa or more from the viewpoint of adsorptivity as an original object, and the like.

As another various embodiments of the present invention, a molded adsorbent for a canister can be more preferable by further satisfying 1 or any 2 or more conditions in the following predetermined items. The preferable combination of the following predetermined items may be arbitrarily selected according to the required conditions and the like.

Specific surface area of shaped adsorbent

In one embodiment of the present invention, the specific surface area of the molded adsorbent may preferably be 100 to 2500m ²/g or less. More specifically, as described below.

In one embodiment of the present invention, the lower limit of the specific surface area of the molded adsorbent may be preferably 100m ²/g or more, more preferably 200m ²/g or more, and still more preferably 300, 500, 700, 900, 1000, 1100, or 1200m ²/g or more.

In one embodiment of the present invention, it is generally preferable that the higher the specific surface area of the activated carbon is, the higher the upper limit of the specific surface area is, from the viewpoint of adsorption/desorption performance, 2500, 2400, 2300, 2200, or 2100m ²/g or less.

By setting the specific surface area in such a range, a molded adsorbent having more excellent adsorption/desorption performance for the vaporized fuel gas can be formed. In addition, in one embodiment of the present invention, as the adsorbent used in the adsorption tank as described above, it is possible to achieve a reduction in pressure loss in the adsorption tank while maintaining a wide specific surface area.

< Total pore volume of molded adsorbent >

In one embodiment of the present invention, the total pore volume of the molded adsorbent may preferably be 0.50 to 1.20cm ³/g or less. More specifically, as described below.

In one embodiment of the present invention, the lower limit of the total pore volume of the molded adsorbent may be preferably 0.50cm ³/g or more, more preferably 0.55cm ³/g or more, still more preferably 0.60, 0.65, 0.70, or 0.75cm ³/g or more.

In one embodiment of the present invention, the upper limit of the total pore volume of the molded adsorbent may be preferably 1.20cm ³/g or less, more preferably 1.15cm ³/g or less, and still more preferably 1.10, 1.05, 1.03, or 1.00cm ³/g or less.

In order to produce a molded adsorbent excellent in adsorption/desorption performance, pressure loss, and the like, the total pore volume is preferably set to the above-described range.

< Average pore diameter (average pore diameter) of molded adsorbent >

In one embodiment of the present invention, the average pore diameter of the molded adsorbent may preferably be 1.50 to 2.50nm. More specifically, as described below.

In one embodiment of the present invention, the lower limit of the average pore diameter of the molded adsorbent may be preferably 1.50nm or more, more preferably 1.60nm or more, and still more preferably 1.70nm or more.

In one embodiment of the present invention, the upper limit of the average pore diameter of the molded adsorbent may be arbitrary, and may be preferably 2.50nm or less, more preferably 2.20nm or less, and still more preferably 2.00 or 1.90nm or less.

In order to produce a molded adsorbent excellent in adsorption/desorption performance, pressure loss, and the like, the average pore diameter is preferably in the above-described range.

Supermicroporous volume of shaped adsorbent: v _0.7 >, V

In the present invention, the term "ultramicropore" means a pore having a pore diameter of 0.7nm or less.

In one embodiment of the present invention, the shaped adsorbent may preferably have a ultramicropore volume of 0.05 to 0.30cm ³/g. More specifically, as described below.

In one embodiment of the present invention, the lower limit of the ultramicropore volume of the molded adsorbent may be preferably 0.05cm ³/g or more, more preferably 0.10cm ³/g or more, still more preferably 0.12 or 0.14cm ³/g or more.

In one embodiment of the present invention, the upper limit of the ultramicropore volume of the molded adsorbent may be preferably 0.30cm ³/g or less, more preferably 0.29cm ³/g or less, still more preferably 0.26, 0.24, 0.22, or 0.20cm ³/g or less.

In order to produce a molded adsorbent excellent in adsorption/desorption performance, pressure loss, and the like, the ultramicropore volume is preferably set to the above-described range.

< Micropore volume of formed adsorbent: v _2.0 >, V

In the present invention, the term "micropores" means micropores having a pore diameter of 2.0nm or less.

In one embodiment of the present invention, the micropore volume of the shaped adsorbent may preferably be in the range of 0.50 to 1.00cm ³/g. More specifically, as described below.

In one embodiment of the present invention, the lower limit of the micropore volume of the molded adsorbent may be preferably 0.50cm ³/g or more, more preferably 0.55, or 0.58cm ³/g or more, and still more preferably 0.59, or 0.60cm ³/g or more.

In one embodiment of the present invention, the upper limit of the micropore volume of the molded adsorbent may be preferably 1.00cm ³/g or less, more preferably 0.90cm ³/g or less, and still more preferably 0.80cm ³/g or less.

In order to produce a molded adsorbent excellent in adsorption/desorption performance, pressure loss, and the like, the micropore volume is preferably in the above-described range.

Pore volume of pores having a pore diameter of more than 0.7nm and 2.0nm or less: v _0.7-2.0 >, V

The pore volume V _0.7-2.0 of pores having a pore diameter of more than 0.7nm and 2.0nm or less can be obtained by using the value a of the ultramicropore volume and the value b of the micropore volume and by the following formula 1.

V _0.7-2.0 = b-a- (formula 1)

In one embodiment of the present invention, the pore volume V _0.7-2.0 of the pores having a pore diameter of more than 0.7nm and 2.0nm or less of the molded adsorbent may be preferably 0.30 to 1.00cm ³/g. More specifically, as described below.

In one embodiment of the present invention, the lower limit of the pore volume V _0.7-2.0 of the pores having a pore diameter of more than 0.7nm and 2.0nm or less of the molded adsorbent may be preferably 0.30cm ³/g or more, more preferably 0.36cm ³/g or more, still more preferably 0.38, 0.40, or 0.43cm ³/g or more.

In one embodiment of the present invention, the upper limit of the pore volume V _0.7-2.0 of the pores having a pore diameter of more than 0.7nm and 2.0nm or less of the molded adsorbent may be preferably 1.00cm ³/g or less, more preferably 0.90cm ³/g or less, still more preferably 0.80, 0.75, 0.70, 0.65, or 0.60cm ³/g or less.

In order to produce a molded adsorbent excellent in adsorption/desorption performance, pressure loss, and the like, the pore volume V _0.7-2.0 is preferably set to the above range.

< The existing ratio of the volume of the ultra-microwell to the volume of the microwell: r _0.7/2.0 >, R

The presence ratio R _0.7/2.0 of the pore volume of the micropores having a pore diameter of 0.7nm or less to the pore volume of the micropores having a pore diameter of 2.0nm or less can be obtained by using the value a of the micropore volume and the value b of the micropore volume, and is obtained by the following formula 2.

R _0.7/2.0 = a/b x 100 (%) · (formula 2)

In one embodiment of the present invention, the ratio R _0.7/2.0 of the super-micropore volume in the molded adsorbent to the micropore volume may preferably be 15.0 to 60.0%. More specifically, as described below.

In one embodiment of the present invention, the lower limit of the presence ratio R _0.7/2.0 of the super-micropore volume in the molded adsorbent to the micropore volume may be preferably 15.0% or more, more preferably 18% or more, and still more preferably 19% or more.

In one embodiment of the present invention, the upper limit of the presence ratio R _0.7/2.0 of the super-micropore volume in the molded adsorbent to the micropore volume may be preferably 60.0% or less, more preferably 50% or less, and still more preferably 40, 30, or 25% or less.

In order to produce a molded adsorbent excellent in adsorption/desorption performance, pressure loss, and the like, the ratio R _0.7/2.0 of the presence of the ultramicropore volume is preferably set to the above-described range.

< Dry Density of shaped adsorbent >

In one embodiment of the present invention, the dry density of the shaped adsorbent may preferably be 0.010 to 0.400g/cm ³. More specifically, as described below.

In the molded adsorbent as an embodiment of the present invention, preferable lower and upper limits of the dry density of the molded adsorbent may be as follows.

The lower limit of the drying density of the molded adsorbent may be preferably 0.010g/cm ³ or more, more preferably 0.015g/cm ³ or more, still more preferably 0.020g/cm ³, 0.030, 0.040, 0.050, or 0.060g/cm ³ or more.

The upper limit of the dry density of the molded adsorbent may be preferably 0.400g/cm ³ or less, more preferably 0.300g/cm ³ or less, and still more preferably 0.250g/cm ³ or less.

By setting the dry density to the above-described range, a molded adsorbent having more excellent adsorption/desorption performance per unit volume required for the canister application can be formed within the range of the capacity of the adsorbent that can be accommodated in the canister. Further, by setting the lower limit or more, even when the sheet-like or disc-like member is formed, deterioration of mechanical properties (for example, strength or the like) can be avoided. The dry density of the molded adsorbent can be adjusted by, for example, the fiber diameter of the carbon fiber, the fiber length adjusted by the stirring force during the defibration of the carbon fiber, or the increase or decrease of the suction force during the suction molding of the mixed slurry with the binder, and the adjustment of the dry density can be one means for optimizing the pressure loss.

N-butane adsorption and Desorption Property of shaped adsorbent

In one embodiment of the present invention, the molded adsorbent preferably has a predetermined n-butane adsorption/desorption performance as the adsorbent. Since the adsorption and desorption performance of n-butane is an index of the adsorption and desorption performance of the vapor-dispersed gas, the molded adsorbent excellent in the adsorption and desorption performance of n-butane is suitable for use in an automobile adsorption tank. For n-butane adsorption and desorption performance, the following adsorption amounts can be expressed as effective adsorption amount ratio of n-butane per unit molded adsorbent: and an adsorption amount when the n-butane is adsorbed repeatedly after being separated from the adsorbent under a predetermined desorption condition after the n-butane is sufficiently adsorbed and penetrated.

In a preferred embodiment of the molded adsorbent of the present invention, the effective adsorption/desorption amount of n-butane (see formula 8 below) obtained by the measurement method shown in the examples below may be preferably 6.00wt% or more, more preferably 6.25wt% or more, still more preferably 6.50, 6.75, or 7.00wt% or more.

In a preferred embodiment of the molded adsorbent, the effective adsorption/desorption rate of n-butane (see formula 9 below) obtained by the measurement method shown in the examples below may be preferably 25.0% or more, more preferably 30.0, 40.0, or 50.0% or more, and still more preferably 60.0, 70.0, or 75.0% or more.

< 0Ppm sustain time of shaped adsorbent >

In general, the longer the maintenance time of 0ppm obtained by the measurement method shown in the following examples, the more preferable the specific numerical value, and in one preferred embodiment of the adsorption molded article of the present invention, the more preferable the maintenance time is 15 minutes or 30 minutes or more, more preferably 40 minutes or more, and still more preferably 50 minutes, 55 minutes, 60 minutes, 65 minutes, 68 minutes, 69 minutes or 70 minutes or more.

The longer the 0ppm hold time means the longer the time until the adsorbent material starts to release the adsorbed species. Therefore, the 0ppm holding time is an index indicating the strength of the adsorption force.

2. Shape of shaped adsorbent

In one embodiment of the present invention, the shape of the molded adsorbent is not particularly limited, and for example, a shape that enables molding and gas flow is suitable. Specific examples of the shape include a columnar shape having an end surface shape such as a circle or a polygon, a truncated cone shape such as a truncated cone or a truncated polygonal cone, and a granular shape, a honeycomb shape, and the like, and preferable examples include a columnar shape, a rectangular parallelepiped shape, and the like. Further, a disc-shaped, sheet-shaped, or plate-shaped molded adsorbent may be formed into a laminate in which a plurality of molded adsorbents are laminated. Several embodiments are shown in fig. 1-3. In the drawings, dimensions such as a length and a thickness are schematically shown for easy understanding of the invention, and the invention is not limited thereto.

The layered adsorbent 1 shown in fig. 1 is a layered body obtained by stacking 4 molded adsorbent sheets 10. The sheet-shaped molded adsorbent 10 is formed by stacking main surfaces 10a of sheets on each other. As one embodiment, each sheet 10 may be a sheet obtained by molding a mixture of activated carbon fibers, granular activated carbon, and a binder into a sheet shape. The binder may preferably be a fibrous binder.

The manner in which the layered adsorbent 1 is housed in the canister is arbitrary. In a preferred embodiment, the main surface 10a of the sheet-shaped molded adsorbent is preferably disposed in a direction not orthogonal to the flow direction of the fluid F such as the vapor, and more preferably, as shown in fig. 1, the main surface a may be disposed substantially parallel to the flow direction of the fluid F such as the vapor. The main surface a is arranged substantially parallel to the flow direction of the fluid F such as the vapor, so that the side end surfaces 10b of the plurality of sheet-shaped molded adsorbents are arranged so as to face the flow direction of the fluid F. By so doing, the pressure loss can be suppressed. In fig. 1, the short side end surface 10b faces the flow direction of the fluid F, but the present invention is not limited thereto, and the long side end surface 10c may face the flow direction of the fluid F.

The entire layered adsorbent may have a rectangular parallelepiped shape or a cubic shape.

Fig. 2 shows another embodiment of the present invention. In the embodiment shown in fig. 2, the molded adsorbent is molded into a disk-like shape. The disc-shaped molded adsorbent may be laminated to form a cylindrical shape.

Fig. 3 shows another embodiment of the present invention. In the embodiment shown in fig. 3, the molded adsorbent is integrally molded into a columnar molded body.

In addition, as another embodiment of the present invention, the following mode may be adopted. A sheet in which granular activated carbon is adhered or held to the surface of an activated carbon fiber sheet may be prepared, and the sheets may be bonded together with an adhesive to form a laminated adsorbent. The laminated adsorbent may be substantially the same as the laminated adsorbent 1 shown in fig. 1 as a whole, with granular activated carbon sandwiched in the vicinity of the interface between the sheets.

As described above, the adsorption laminate according to one embodiment of the present invention can be easily processed or molded into various shapes, and is a material excellent in handling properties.

3. Activated carbon fiber

In one embodiment of the present invention, as 1 kind of activated carbon, activated carbon fibers may be used. Hereinafter, embodiments of the activated carbon fiber usable in the present invention will be described in more detail. The activated carbon fiber usable in the molded adsorbent for a canister can be a more preferable embodiment by further satisfying 1 or any 2 or more conditions in the following predetermined items. The preferable combination of the following predetermined items may be arbitrarily selected according to the required conditions and the like.

< Fiber diameter of activated carbon fiber >

In one embodiment of the present invention, the fiber diameter of the activated carbon fiber usable in the molded adsorbent may be preferably 6.0 to 70.0 μm. More specifically, as described below.

In one embodiment of the present invention, the lower limit of the fiber diameter of the activated carbon fiber usable in the molded adsorbent may be preferably 4.0 μm or more, more preferably 6.0 μm or more, and still more preferably 8.0, 10.0, 12.0, 14.0, 18.0, 19.0, or 20.0 μm or more.

In one embodiment of the present invention, the upper limit of the fiber diameter of the activated carbon fiber usable in the molded adsorbent is arbitrary from the viewpoint of suppressing pressure loss, and may be, for example, 70.0 μm or less, preferably 65.0 or 60.0 μm or less, more preferably 59.0, 58.0, 57.0, 56.0, or 55.0 μm or less, in view of the balance with adsorption/desorption performance.

When the fiber diameter of the activated carbon fiber usable in the molded adsorbent is in the above range, the molded adsorbent can be formed which can further suppress pressure loss.

< Average value of fiber length of activated carbon fiber (or average fiber length) >

In one embodiment of the present invention, the average fiber length of the activated carbon fibers usable in the molded adsorbent may be preferably 300 to 10000 μm. More specifically, as described below.

In one embodiment of the present invention, the lower limit of the average fiber length value of the activated carbon fibers usable in the molded adsorbent may be preferably 300 μm or more, more preferably 500, 600, 700, 800, 850, or 900 μm or more, and still more preferably 950 μm or more.

In one embodiment of the present invention, the upper limit of the average fiber length value of the activated carbon fibers usable in the molded adsorbent may be preferably 10000, 7500, or 5000 μm or less, more preferably 4000, 3000, 2500, 2000, or 1500 μm or less, and still more preferably 1200 μm or less.

When the average fiber length of the activated carbon fibers used in the molded adsorbent is within the above range, the molded adsorbent can be formed in which the pressure loss can be further suppressed.

< Coefficient of variation of fiber length of activated carbon fiber >

In one embodiment of the present invention, the fiber length variation coefficient of the activated carbon fibers usable in the molded adsorbent may be preferably 0.100 to 2.500. More specifically, as described below.

In one embodiment of the present invention, the lower limit of the fiber length variation coefficient of the activated carbon fibers usable in the molded adsorbent may be preferably 0.100 or more, more preferably 0.200, 0.300, 0.400, or 0.500 or more, and still more preferably 0.600 or more.

In one embodiment of the present invention, the upper limit of the fiber length variation coefficient of the activated carbon fibers usable in the molded adsorbent may be preferably 2.500 or less, more preferably 2.000, 1.500, 1.000, 0.900 or less, and still more preferably 0.700 or less.

When the fiber length variation coefficient of the activated carbon fibers usable in the molded adsorbent is within the above range, the molded adsorbent can be formed which can further suppress pressure loss.

< Titer of precursor of activated carbon fiber >

In order to obtain the activated carbon fiber having such a fiber diameter, the fiber diameter (as fineness) of the fiber which is a precursor of the activated carbon fiber is preferably in the following range. That is, it can be said that the following fibers are preferably used as precursors for obtaining activated carbon fibers capable of suppressing pressure loss.

In one embodiment of the present invention, the fiber diameter (as fineness) of the fibers to be the precursor may be preferably 4.0 to 70.0dtex. More specifically, as described below.

The lower limit of the fiber diameter (as fineness) of the fibers to be the precursor may be preferably 4.0dtex or more, more preferably 5.0dtex or more, and still more preferably 8.0, 10.0, 12.0, or 15.0dtex or more.

The upper limit of the fiber diameter (as fineness) of the fibers to be the precursor may be, for example, 70.0dtex or less, preferably 65.0 or 60.0dtex or less, and more preferably 59.0, 58.0, or 57.0dtex.

Specific surface area of activated carbon fiber

In one embodiment of the present invention, the specific surface area of the activated carbon fiber usable in the molded adsorbent may preferably be 1100 to 2400m ²/g. More specifically, as described below.

In one embodiment of the present invention, the lower limit of the specific surface area of the activated carbon fiber usable in the molded adsorbent may be preferably 1100m ²/g or more, more preferably 1200, 1300, 1400, 1500, or 1600m ²/g or more, and still more preferably 1700, or 1800m ²/g or more.

In one embodiment of the present invention, from the viewpoint of adsorption performance, the larger the specific surface area of the activated carbon fiber usable in the molded adsorbent is, the more preferable, and in the case of an adsorbent for a canister, the upper limit of the specific surface area may be 2400, 2300, 2200, or 2100m ²/g or less.

In order to produce a molded adsorbent excellent in adsorption/desorption performance, the specific surface area of the activated carbon fiber is preferably in the above-described range. In addition, it is preferable to suppress pressure loss while maintaining a large specific surface area.

< Total pore volume of activated carbon fiber >

In one embodiment of the present invention, the total pore volume of the activated carbon fibers usable in the molded adsorbent may preferably be 0.50 to 1.20cm ³/g. More specifically, as described below.

In one embodiment of the present invention, the lower limit of the total pore volume of the activated carbon fibers usable in the molded adsorbent may be preferably 0.50cm ³/g or more, more preferably 0.60 or 0.70cm ³/g or more, and still more preferably 0.80cm ³/g or more.

In one embodiment of the present invention, the upper limit of the total pore volume of the activated carbon fibers usable in the molded adsorbent may be preferably 1.20cm ³/g or less, more preferably 1.10cm ³/g or less, and still more preferably 1.00cm ³/g or less.

In order to produce a molded adsorbent excellent in adsorption/desorption performance, pressure loss, and the like, the total pore volume of the activated carbon fiber is preferably in the above-described range.

< Average pore diameter (average pore diameter) of activated carbon fiber >

In one embodiment of the present invention, the average pore diameter of the activated carbon fibers usable in the molded adsorbent may preferably be 1.69 to 4.00nm. More specifically, as described below.

In one embodiment of the present invention, the lower limit of the average pore diameter of the activated carbon fibers usable in the molded adsorbent may be preferably 1.69nm or more, more preferably 1.70nm or more, still more preferably 1.72 nm or 1.75nm or more.

In one embodiment of the present invention, the upper limit of the average pore diameter of the activated carbon fibers usable in the molded adsorbent may be arbitrary, and may be preferably 4.00nm or less, more preferably 3.50nm or less, and still more preferably 3.00nm or less.

In order to produce a molded adsorbent excellent in adsorption/desorption performance, pressure loss, and the like, it is preferable to set the average pore diameter of the activated carbon fiber to the above-described range.

Supermicroporous volume of activated carbon fiber: v _0.7 >, V

In one embodiment of the present invention, the activated carbon fiber usable in the molded adsorbent may preferably have a ultramicropore volume of 0.05 to 0.30cm ³/g. More specifically, as described below.

In one embodiment of the present invention, the lower limit of the ultramicropore volume of the activated carbon fiber usable in the molded adsorbent may be preferably 0.05cm ³/g or more, more preferably 0.08cm ³/g or more, and still more preferably 0.10cm ³/g or more.

In one embodiment of the present invention, the upper limit of the ultramicropore volume of the activated carbon fibers usable in the molded adsorbent may be preferably 0.30cm ³/g or less, more preferably 0.25cm ³/g or less, still more preferably 0.23, 0.20, 0.18, or 0.15cm ³/g or less.

In order to produce a molded adsorbent excellent in adsorption/desorption performance, pressure loss, and the like, the ultrafine pore volume of the activated carbon fiber is preferably in the above-described range.

< Micropore volume of activated carbon fiber: v _2.0 >, V

In one embodiment of the present invention, the micropore volume of the activated carbon fibers usable in the shaped adsorbent may preferably be 0.40 to 1.00cm ³/g. More specifically, as described below.

In one embodiment of the present invention, the lower limit of the micropore volume of the activated carbon fiber usable in the molded adsorbent may be preferably 0.40cm ³/g or more, more preferably 0.50 or 0.55cm ³/g or more, still more preferably 0.60 or 0.62cm ³/g or more.

In one embodiment of the present invention, the upper limit of the micropore volume of the activated carbon fiber usable in the molded adsorbent may be preferably 1.00cm ³/g or less, more preferably 0.90cm ³/g or less, and still more preferably 0.80cm ³/g or less.

In order to produce a molded adsorbent excellent in adsorption/desorption performance, pressure loss, and the like, the micropore volume of the activated carbon fiber is preferably in the above-described range.

Pore volume of pores having a pore diameter of more than 0.7nm and 2.0nm or less: v _0.7-2.0 (relating to activated carbon fiber) >, of

In one embodiment of the activated carbon fiber usable in the molded adsorbent, the pore volume V _0.7-2.0 of the pores having a pore diameter of more than 0.7nm and 2.0nm or less may be preferably 0.20 to 1.20cm ³/g. More specifically, as described below.

In one embodiment of the activated carbon fiber usable in the molded adsorbent, the lower limit of the pore volume V _0.7-2.0 of the pores having a pore diameter of more than 0.7nm and 2.0nm or less may be preferably 0.20cm ³/g or more, more preferably 0.30, 0.36, or 0.40cm ³/g or more, still more preferably 0.43, 0.45, or 0.50cm ³/g or more.

In one embodiment of the activated carbon fiber usable in the molded adsorbent, the upper limit of the pore volume V _0.7-2.0 of the pores having a pore diameter of more than 0.7nm and 2.0nm or less may be preferably 1.20cm ³/g or less, more preferably 1.00cm ³/g or less, still more preferably 0.90, 0.80, 0.75, 0.70, 0.65, or 0.60cm ³/g or less.

In order to produce a molded adsorbent excellent in adsorption/desorption performance, pressure loss, and the like, the pore volume V _0.7-2.0 of the activated carbon fiber is preferably set to the above range.

< The existing ratio of the volume of the ultra-microwell to the volume of the microwell: r _0.7/2.0 (concerning activated carbon fiber) >, and

In one embodiment of the activated carbon fiber usable in the molded adsorbent, the ratio R _0.7/2.0 of the ultramicropore volume to the micropore volume may be preferably 15.0 to 60.0%. More specifically, as described below.

In one embodiment of the activated carbon fiber usable in the molded adsorbent, the lower limit of the presence ratio R _0.7/2.0 of the ultramicropore volume to the micropore volume may be preferably 15.0% or more, more preferably 18.0% or more, and still more preferably 19.0% or more.

In one embodiment of the activated carbon fiber usable in the molded adsorbent, the upper limit of the presence ratio R _0.7/2.0 of the ultramicropore volume to the micropore volume may be preferably 60.0% or less, more preferably 50.0% or less, and still more preferably 40.0, 30.0, or 25.0% or less.

In order to produce a molded adsorbent excellent in adsorption/desorption performance, pressure loss, and the like, the ratio R _0.7/2.0 of the activated carbon fiber to the ultramicropore volume is preferably set to the above range.

Weight per square meter (weight per unit area) of activated carbon fiber sheet

In one embodiment of the present invention, activated carbon fibers, which are one of the materials used for the molded adsorbent, may be prepared in the form of an activated carbon fiber sheet. The weight per square meter of the activated carbon fiber sheet is preferably in the following range.

In one embodiment of the present invention, the weight per square meter of activated carbon fibers that may be used in the shaped adsorbent may preferably be 50.0 to 200g/m ². More specifically, as described below.

The lower limit of the weight per square meter may be preferably 50.0g/m ² or more, more preferably 60.0g/m ² or more, still more preferably 70.0 or 80.0g/m ² or more.

The upper limit of the weight per square meter may be preferably 200g/m ² or less, more preferably 150g/m ² or less, still more preferably 120, 110 or 100g/m ² or less.

In order to produce a molded adsorbent excellent in adsorption/desorption performance, pressure loss, and the like in the range of the capacity of the adsorbent that can be accommodated in the canister, the weight per square meter is preferably in the above-described range.

< Moisture Density of activated carbon fiber (at 23 ℃ C., relative humidity 50%) >

In one embodiment of the present invention, the activated carbon fibers that can be used in the shaped adsorbent may preferably have a prescribed density. As the density, the humidity control density may be used as an index. In the present invention, the humidity control density is a density measured at 23℃and a relative humidity of 50%.

In one embodiment of the present invention, the activated carbon fiber usable in the molded adsorbent may preferably have a moisture control density of 0.010 to 0.400g/cm ³. More specifically, as described below.

In one embodiment of the present invention, the lower limit of the humidity control density (density at 23 ℃ C., relative humidity 50%) of the activated carbon fibers usable in the molded adsorbent may be preferably 0.010g/cm ³ or more, more preferably 0.015, 0.020, or 0.030g/cm ³ or more, still more preferably 0.040, or 0.050g/cm ³ or more.

In one embodiment of the present invention, the upper limit of the humidity control density of the activated carbon fibers usable in the molded adsorbent may be preferably 0.400g/cm ³ or less, more preferably 0.300g/cm ³ or less, and still more preferably 0.200, 0.150, 0.140, 0.130, 0.120, 0.110, or 0.100g/cm ³ or less.

By setting the moisture control density of the activated carbon fibers usable in the molded adsorbent to the above-described range, a molded adsorbent having more excellent adsorption/desorption performance per unit volume required for the adsorbent for the canister can be produced. Further, by setting the lower limit or more as described above, a decrease in mechanical properties (for example, strength or the like) can be avoided. The wet density of the activated carbon fibers usable in the molding adsorbent can be adjusted by adjusting the fiber diameter of the carbon fibers, the fiber length due to adjustment of stirring force during defibration of the carbon fibers, and the increase or decrease of suction force during suction molding of the mixed slurry with the binder, and the adjustment of the wet density can be 1 means for optimizing the pressure loss.

< Moisture content of activated carbon fiber >

In one embodiment of the present invention, the activated carbon fibers that can be used in the shaped adsorbent preferably have a specified moisture content.

In one embodiment of the present invention, the moisture content (at 23 ℃ C., relative humidity 50%) of the activated carbon fibers usable in the molded adsorbent may be preferably 1.0 to 30.0%. More specifically, as described below.

In one embodiment of the present invention, the lower limit of the moisture content under the conditions of 23 ℃ and 50% relative humidity may be preferably 1.0% or more, more preferably 2.0% or more, and still more preferably 3.0% or more.

In one embodiment of the present invention, the upper limit of the moisture content under the condition of 23 ℃ and 50% relative humidity may be preferably 30.0% or less, more preferably 20.0% or less, still more preferably 10.0% or less, or 25.0% or less.

In order to produce a molded adsorbent excellent in adsorption/desorption performance, the moisture content of the activated carbon fiber under the above conditions is preferably in the above range.

4. Granular activated carbon

In the present invention, granular activated carbon means activated carbon having an average particle diameter of 100 to 3000 μm.

In one embodiment of the present invention, granular activated carbon may be used as 1 kind of activated carbon. Hereinafter, embodiments of granular activated carbon usable in the present invention will be described in more detail. In one embodiment of the present invention, granular activated carbon usable in a molded adsorbent for a canister may be a more preferable embodiment by further satisfying 1 or any 2 or more conditions in the following predetermined items. The preferable combination of the following predetermined items may be arbitrarily selected according to the required conditions and the like.

< Average particle diameter of granular activated carbon >)

In one embodiment of the present invention, the average particle diameter of the granular activated carbon usable in the molded adsorbent may be preferably 100 to 3000 μm. More specifically, as described below.

In one embodiment of the present invention, the lower limit of the average particle diameter of the granular activated carbon usable in the molded adsorbent may be preferably 100 μm or more, more preferably 150, 200, 250, 300, 350, or 400 μm or more, and still more preferably 450 μm or more.

In one embodiment of the present invention, the upper limit of the average particle diameter of the granular activated carbon usable in the molded adsorbent may be preferably 3000 μm or less, more preferably 2500, 2000, 1500, 1000, or 800 μm or less, and still more preferably 600 μm or less.

When the average particle diameter of the granular activated carbon used in the molded adsorbent is in the above range, the molded adsorbent can be formed in which the pressure loss can be further suppressed.

Particle diameter variation coefficient of granular active carbon

In one embodiment of the present invention, the particle diameter variation coefficient of the granular activated carbon usable in the molded adsorbent may be preferably 0.01 to 2.500. More specifically, as described below.

In one embodiment of the present invention, the lower limit of the particle diameter variation coefficient of the granular activated carbon usable in the molded adsorbent may be preferably 0.01 or more, more preferably 0.025, 0.050, 0.075, 0.100, 0.125, or 0.150 or more, and still more preferably 0.175 or more.

In one embodiment of the present invention, the upper limit of the particle diameter variation coefficient of the granular activated carbon usable in the molded adsorbent may be preferably 2.500 or less, more preferably 2.000, 1.500, 1.000, 0.800, 0.600, 0.500, 0.400, or 0.300 or less, and still more preferably 0.200 or less.

When the particle diameter variation coefficient of the granular activated carbon usable for the molded adsorbent is in the above range, the molded adsorbent can be formed which can further suppress pressure loss.

Specific surface area of granular activated carbon

In one embodiment of the present invention, the specific surface area of the granular activated carbon that can be used in the shaped adsorbent may preferably be 1100 to about 2400m ²/g. More specifically, as described below.

In one embodiment of the present invention, the lower limit of the specific surface area of the granular activated carbon usable in the molded adsorbent may be preferably 1100m ²/g or more, more preferably 1200, 1300, 1400, 1500, or 1600m ²/g or more, and still more preferably 1700, or 1800m ²/g or more.

In one embodiment of the present invention, from the viewpoint of adsorption performance, the larger the specific surface area of the granular activated carbon usable in the molded adsorbent is, the more preferable, and in the case of an adsorbent for a canister, the upper limit of the specific surface area may be 2400, 2300, 2200, or 2100m ²/g or less.

In order to produce a molded adsorbent excellent in adsorption/desorption performance, the specific surface area of the granular activated carbon is preferably in the above-described range. In addition, in order to suppress pressure loss while maintaining a large specific surface area, it is preferable.

< Total pore volume of granular activated carbon >

In one embodiment of the present invention, the total pore volume of the granular activated carbon usable in the molded adsorbent is preferably 0.50 to 1.20cm ³/g. More specifically, as described below.

In one embodiment of the present invention, the lower limit of the total pore volume of the granular activated carbon usable in the molded adsorbent is preferably 0.50cm ³/g or more, more preferably 0.60 or 0.70cm ³/g or more, and still more preferably 0.75cm ³/g or more.

In one embodiment of the present invention, the upper limit of the total pore volume of the granular activated carbon usable in the molded adsorbent is preferably 1.20cm ³/g or less, more preferably 1.10cm ³/g or less, and still more preferably 1.00cm ³/g or less.

In order to produce a molded adsorbent excellent in adsorption/desorption performance, pressure loss, and the like, the total pore volume of the granular activated carbon is preferably in the above-described range.

< Average pore diameter (average pore diameter) of granular activated carbon >

In one embodiment of the present invention, the average pore diameter of the granular activated carbon contained in the molded adsorbent may preferably be 1.69 to 4.00nm. More specifically, as described below.

In one embodiment of the present invention, the lower limit of the average pore diameter of the granular activated carbon usable in the molded adsorbent may be preferably 1.69nm or more, more preferably 1.70nm or more, still more preferably 1.72 nm or 1.75nm or more.

In one embodiment of the present invention, the upper limit of the average pore diameter of the granular activated carbon usable in the molded adsorbent may be arbitrary, and may be preferably 4.00nm or less, more preferably 3.50nm or less, and still more preferably 3.00nm or less.

In order to produce a molded adsorbent excellent in adsorption/desorption performance, pressure loss, and the like, it is preferable to set the average pore diameter of the granular activated carbon to the above-described range.

Ultra micropore volume of granular activated carbon: v _0.7 >, V

In one embodiment of the present invention, the ultrafine pore volume of the granular activated carbon usable in the molded adsorbent may preferably be 0.05 to 0.30cm ³/g. More specifically, as described below.

In one embodiment of the present invention, the lower limit of the ultramicropore volume of the granular activated carbon usable in the molded adsorbent may be preferably 0.05cm ³/g or more, more preferably 0.08cm ³/g or more, and still more preferably 0.10cm ³/g or more.

In one embodiment of the present invention, the upper limit of the ultramicropore volume of the granular activated carbon usable in the molded adsorbent may be preferably 0.30cm ³/g or less, more preferably 0.25cm ³/g or less, still more preferably 0.23, 0.20, 0.18, or 0.15cm ³/g or less.

In order to produce a molded adsorbent excellent in adsorption/desorption performance, pressure loss, and the like, the ultrafine pore volume of the granular activated carbon is preferably in the above-described range.

Micropore volume of granular activated carbon: v _2.0 >, V

In one embodiment of the present invention, the micropore volume of the granular activated carbon usable in the shaped adsorbent may preferably be 0.40 to 1.00cm ³/g. More specifically, as described below.

In one embodiment of the present invention, the lower limit of the micropore volume of the granular activated carbon usable in the molded adsorbent may be preferably 0.40cm ³/g or more, more preferably 0.50 or 0.55cm ³/g or more, still more preferably 0.60 or 0.62cm ³/g or more.

In one embodiment of the present invention, the upper limit of the micropore volume of the granular activated carbon usable in the molded adsorbent may be preferably 1.00cm ³/g or less, more preferably 0.90cm ³/g or less, and still more preferably 0.80cm ³/g or less.

In order to produce a molded adsorbent excellent in adsorption/desorption performance, pressure loss, and the like, the micropore volume of the granular activated carbon is preferably in the above-described range.

Pore volume of pores having a pore diameter of more than 0.7nm and 2.0nm or less: v _0.7-2.0 (granular activated carbon) >)

In one embodiment of the granular activated carbon usable in the molded adsorbent, the pore volume V _0.7-2.0 of the pores having a pore diameter of more than 0.7nm and 2.0nm or less may be preferably 0.20 to 1.20cm ³/g. More specifically, as described below.

In one embodiment of the granular activated carbon usable in the molded adsorbent, the lower limit of the pore volume V _0.7-2.0 of the pores having a pore diameter of more than 0.7nm and 2.0nm or less may be preferably 0.20cm ³/g or more, more preferably 0.30, 0.36, or 0.40cm ³/g or more, still more preferably 0.43, 0.45, or 0.50cm ³/g or more.

In one embodiment of the granular activated carbon that can be used in the molded adsorbent, the upper limit of the pore volume V _0.7-2.0 of the pores having a pore diameter of more than 0.7nm and 2.0nm or less may be preferably 1.20cm ³/g or less, more preferably 1.00cm ³/g or less, still more preferably 0.90, 0.80, 0.75, 0.70, 0.65, or 0.60cm ³/g or less.

In order to produce a molded adsorbent excellent in adsorption/desorption performance, pressure loss, and the like, the pore volume V _0.7-2.0 of the granular activated carbon is preferably set to the above range.

< The existing ratio of the volume of the ultra-microwell to the volume of the microwell: r _0.7/2.0 (concerning granular activated carbon) >)

In one embodiment of the granular activated carbon usable in the molded adsorbent, the ratio R _0.7z/2.0 of the ultramicropore volume to the micropore volume may be preferably 15.0 to 60.0%. More specifically, as described below.

In one embodiment of the granular activated carbon usable in the molded adsorbent, the lower limit of the presence ratio R _0.7/2.0 of the ultramicropore volume to the micropore volume may be preferably 15.0% or more, more preferably 18.0% or more, and still more preferably 19.0% or more.

In one embodiment of the granular activated carbon usable in the molded adsorbent, the upper limit of the presence ratio R _0.7/2.0 of the ultramicropore volume to the micropore volume may be preferably 60.0% or less, more preferably 50.0% or less, and still more preferably 40.0, 30.0, or 25.0% or less.

In order to produce a molded adsorbent excellent in adsorption/desorption performance, pressure loss, and the like, the ratio R _0.7/2.0 of the ultrafine pore volume of the granular activated carbon is preferably set to the above range.

< Humidifying Density of granular activated carbon (at 23 ℃ C., relative humidity 50%) >

In one embodiment of the present invention, the granular activated carbon that can be used in the shaped adsorbent may preferably have a prescribed density. As the density, the humidity control density may be used as an index. In the present invention, the humidity control density is a density measured at 23℃and a relative humidity of 50%.

In one embodiment of the present invention, the moisture control density (density at 23 ℃ C., relative humidity 50%) of the granular activated carbon usable in the molded article for water purification may be preferably 0.10 to 0.80g/cm ³. More specifically, as described below.

In one embodiment of the present invention, the lower limit of the humidity control density (density at 23 ℃ C., relative humidity 50%) of the granular activated carbon usable in the molded adsorbent may be preferably 0.10g/cm ³ or more, more preferably 0.15, 0.2, 0.25, or 0.30g/cm ³ or more.

In one embodiment of the present invention, the upper limit of the humidity control density of the granular activated carbon usable in the molded adsorbent may be preferably 0.80g/cm ³ or less, more preferably 0.70, 0.60, 0.55, 0.50, or 0.45g/cm ³ or less.

In order to produce a molded adsorbent excellent in adsorption/desorption performance, pressure loss, and the like, the moisture content under the above conditions is preferably in the above range.

< Moisture content of granular activated carbon >

In one embodiment of the present invention, the granular activated carbon that can be used in the shaped adsorbent preferably has a specified moisture content.

In one embodiment of the present invention, the moisture content (at 23 ℃ C., relative humidity 50%) of the granular activated carbon usable in the molded adsorbent may be preferably 1.0 to 30.0%. More specifically, as described below.

In one embodiment of the present invention, the molded adsorbent does not exclude other components than the activated carbon fiber, the granular activated carbon, and the binder, but the addition of other components is preferably not to hinder the effect related to the suppression of the pressure loss or to stay to such an extent that the substantial meaning is not lost.

5. Adsorption tank

The molded adsorbent of the present invention is suitable as an adsorbent contained in an automobile canister. That is, as another embodiment, the present invention may also provide an automobile canister.

In one embodiment of the present invention, the automobile canister is provided with the molded adsorbent as an adsorbent. The structure of the automobile canister is not particularly limited, and a general structure may be employed. For example, as the automobile canister, there is an automobile canister having the following structure.

An adsorption tank provided with:

A housing;

An adsorbing material chamber for accommodating an adsorbing material in the case;

A first opening portion for communicating the adsorbent chamber with the engine in a gas-movable manner;

A second opening portion for communicating the adsorbent chamber with the fuel tank in a gas-movable manner; and

And a third opening portion for communicating the adsorbent chamber with the outside air in a gas-movable manner when the pressure is determined by the adsorbent chamber or the outside air load.

In one embodiment of the present invention, the molded adsorbent of the present invention described above can be used as the adsorbent in the canister. As described above, the molded adsorbent of the present invention can reduce the pressure loss, and therefore, even if the adsorbent is filled without any gap, the pressure loss can be suppressed as compared with the case of filling a conventional activated carbon fiber sheet or the like.

The first opening, the second opening, and the third opening are the delivery inlets through which the gas flows out and in. The arrangement of the openings as the gas supply/discharge ports is not particularly limited, and the third opening as the external gas supply/discharge port is preferably arranged at a position where the gas sufficiently passes through the adsorbent when the gas moves between the first opening and/or the second opening. For example, embodiments may be employed in which the first opening and the second opening are provided in a first side surface portion of the case, and the third opening is provided in a second side surface portion located opposite to the first side surface portion.

The adsorbent chamber may be divided into a plurality of chambers. For example, the adsorbent chamber may be divided into 2 or more regions by partition walls. As the partition wall, a porous plate having air permeability or the like may be used. Further, an additional second housing may be provided separately from the first housing, and an adsorbent chamber may be additionally installed so as to communicate the first housing and the second housing through a gas passage. In the case where a plurality of regions or cases are provided as described above, as a preferred embodiment, the adsorbent or the adsorbent chamber may be disposed so that the adsorption capacity in each region or case unit becomes smaller in order from the first opening or the second opening (in which the gas flows from the engine or the fuel tank into the first opening or the second opening) toward the third opening side.

As a specific example, a composite canister including a main canister (first housing) and a second canister (second housing) that is attached to the inlet side of the external air compared to the main canister may be exemplified. In the case where a plurality of regions or cases are provided as described above, the region or case where the vapor-phase gas initially flows in from the engine or the fuel tank is taken as the main body (first region or first case) having the largest storage volume, and the conventional inexpensive activated carbon is stored in the main body, while the molded adsorbent excellent in low-concentration adsorption/desorption performance of the present invention is stored in the second region or second case having a relatively small storage volume, whereby the cost can be reduced and the high-performance adsorption tank can be manufactured.

In the case where there are a plurality of adsorbent chambers, the concentration of the vaporized fuel gas flowing in from the front layer becomes thinner in the adsorbent chamber located further downstream when viewed from the engine or the fuel tank (i.e., the adsorbent chamber disposed closer to the outside air feed-in port). Therefore, activated carbon having a high n-butane adsorption capacity at a low concentration of about 0.2% is suitable as an adsorbent stored in an adsorbent chamber located in a second region or second casing located further downstream or further downstream than the second region or second casing when viewed from an engine or a fuel tank. In addition, when activated carbon is used in the adsorbent chamber closer to the inlet for the outside air, the molded adsorbent of the present invention is suitable as an adsorbent for an automobile canister because the amount of effective adsorption and desorption by purge (purge) is high, even in view of being able to reduce the amount of leakage of the vaporized fuel gas when the automobile is stopped for a long period of time.

Therefore, as one embodiment of the canister, for example, the following modes are given.

An adsorption tank for an automobile, comprising a main chamber and a sub-chamber for accommodating an adsorbent,

The auxiliary chamber has a smaller volume for accommodating the adsorbent than the main chamber, and is disposed closer to an opening communicating with the outside air,

The adsorbent of the present invention is contained in the sub-chamber.

In the above embodiment, 1 main chamber and 2 sub chambers may be provided, respectively. In the case where the number of adsorbent chambers is 3 or more, the molded adsorbent of the present invention may be housed in at least 1 adsorbent chamber of the sub-chamber, and preferably may be provided in the sub-chamber closest to the opening communicating with the outside air.

6. Method for manufacturing molded adsorbent

The molded adsorbent of the present invention can be obtained by molding an adsorbent containing activated carbon fibers or the like into a predetermined shape. As the activated carbon fiber, for example, an activated carbon fiber satisfying the requirements (specific surface area, V _0.7-2.0、R_0.7/2.0, etc.) shown as preferable index in the above can be used.

In one embodiment of the present invention, the molded adsorbent can be obtained by mixing and molding activated carbon fibers, granular activated carbon, and a binder. In another embodiment of the present invention, a laminate may be formed by bonding sheets of granular activated carbon to the surface of an activated carbon fiber sheet using a binder.

The activated carbon fiber can be produced, for example, by carbonizing and activating a fiber having a predetermined fiber diameter. The carbonization and activation may be carried out by a general method.

Hereinafter, an embodiment of producing an activated carbon fiber sheet using a precursor sheet (raw sheet) will be described as an example.

6-1 Preparation of raw sheet (precursor fiber sheet)

< Kind of fiber >

As the fibers constituting the raw material sheet, for example, cellulose fibers, pitch fibers, PAN fibers, phenolic resin fibers, and the like are cited, and cellulose fibers are preferable.

Cellulose fiber

The cellulose-based fiber is a fiber comprising cellulose and/or a derivative thereof as a main component. The cellulose and cellulose derivative may be any of cellulose produced from chemical synthetic products, plants, regenerated cellulose, bacteria, and the like. As the cellulose-based fibers, for example, fibers formed of a plant-based cellulose material obtained from trees or the like, or fibers formed of a long-fiber regenerated cellulose material obtained by dissolving a plant-based cellulose material (cotton, pulp or the like) by chemical treatment, or the like, can be preferably used. The fiber may contain lignin, hemicellulose, and other components.

Examples of the raw material of the cellulose-based fibers (plant-based cellulose material, regenerated cellulose material) include plant-based cellulose fibers such as cotton (short-fiber cotton, medium-fiber cotton, long-fiber cotton, ultralong-fiber cotton, etc.), hemp, bamboo, flat-fiber, fragrant, banana, and capsule-like fibers; cuprammonium rayon, viscose rayon (polynosic rayon), regenerated cellulose fibers such as cellulose using bamboo as a raw material; purified cellulose fibers spun with an organic solvent (N-methylmorpholine N-oxide); acetate fibers such as diacetate and triacetate; etc. Among these, at least one selected from the group consisting of cuprammonium rayon, viscose rayon, and purified cellulose fiber is preferable from the viewpoint of ease of obtaining.

The diameter of the single fibers constituting the cellulose fibers is preferably 5 to 75. Mu.m, and the density is 1.4 to 1.9m ³/g.

The form of the cellulose fiber is not particularly limited, and depending on the purpose, a cellulose fiber such as a raw yarn (raw yarn), a false twisted yarn (FALSE TWISTED YARN), a dyed yarn (dyed yarn), a single yarn (SINGLE YARN), a doubled yarn (folded yarn), a covering yarn (covering yarn) and the like can be used. In addition, when the cellulose fiber contains 2 or more kinds of raw materials, a blended yarn, a twisted yarn, or the like can be produced. Further, as the cellulose-based fibers, two or more kinds of the above-described raw materials may be used singly or in combination. Among these, from the viewpoint of having both the moldability and the mechanical strength of the composite material, untwisted yarn is preferable.

< Fibrous sheet >)

The fiber sheet is a material obtained by processing a large number of fibers into a thin and large sheet, and includes woven fabrics, knitted fabrics, nonwoven fabrics, and the like.

The method for weaving the cellulose fibers is not particularly limited, and a usual method may be used, and the fabric weave of the fabric is not particularly limited, and three kinds of basic weaves, i.e., plain weave, twill weave, and satin weave, may be used.

The gap between the warp and weft of the cellulose fiber may be preferably 0.1 to 0.8mm, more preferably 0.2 to 0.6mm, and still more preferably 0.25 to 0.5mm in the woven fabric formed of the cellulose fiber. Further, the woven fabric formed of the cellulose fibers may have a weight per unit area of preferably 50 to 500g/m ², more preferably 100 to 400g/m ².

By setting the cellulose fibers and the woven fabric made of cellulose fibers to the above ranges, the carbon fiber woven fabric obtained by heat-treating the woven fabric can be a woven fabric having excellent strength.

The method for producing the nonwoven fabric is not particularly limited, and examples thereof include: a method of obtaining a fiber sheet from the fibers cut to an appropriate length by a dry method, a wet method, or the like; and a method of directly obtaining a fiber sheet from the solution using an electrospinning method or the like. Further, after the nonwoven fabric is obtained, a treatment with resin bonding, thermal bonding, hydroentanglement, needling, or the like may be applied for the purpose of bonding the fibers to each other.

6-2 Catalyst

In production method embodiment 1, the catalyst is held in the raw sheet prepared in the above manner. The catalyst is held in the raw sheet and carbonized, and further activated with steam, carbon dioxide, air gas, or the like, whereby a porous activated carbon fiber sheet can be obtained. As the catalyst, for example, a phosphoric acid-based catalyst, an organic sulfonic acid-based catalyst, and the like can be used.

Phosphoric acid catalyst

Examples of the phosphoric acid-based catalyst include phosphoric acid, metaphosphoric acid, pyrophosphoric acid, phosphorous acid, phosphonic acid, phosphinic acid, and phosphorous acid; monoammonium phosphate, diammonium phosphate, triammonium phosphate, dimethylphosphonopropionamide, ammonium polyphosphate, polyphosphazene chloride; and condensates of phosphoric acid, tetrakis (hydroxymethyl) phosphonium salt or tris (1-aziridinyl) phosphine oxide with urea, thiourea, melamine, guanine, cyanamide, hydrazine, dicyandiamide or hydroxymethyl derivatives thereof, etc., and preferable examples thereof include diammonium hydrogen phosphate. The phosphoric acid catalyst may be used alone or in combination of at least 2. When the phosphoric acid-based catalyst is used in the form of an aqueous solution, the concentration thereof may be preferably 0.05 to 2.0mol/L, more preferably 0.1 to 1.0mol/L.

< Organic sulfonic acid catalyst >)

As the organic sulfonic acid, an organic compound having 1 or more sulfonic groups can be used, and for example, a compound in which a sulfonic group is bonded to various carbon skeletons of an aliphatic system, an aromatic system, or the like can be used. As the organic sulfonic acid-based catalyst, a low molecular weight organic sulfonic acid-based catalyst is preferable from the viewpoint of disposal.

Examples of the organic sulfonic acid catalyst include compounds represented by R-SO ₃ H (wherein R represents a linear/branched alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, or an aryl group having 6 to 20 carbon atoms, and each of the alkyl group, cycloalkyl group, and aryl group may be substituted with an alkyl group, hydroxyl group, or halogen group). Examples of the organic sulfonic acid-based catalyst include methane sulfonic acid, ethane sulfonic acid, propane sulfonic acid, 1-hexane sulfonic acid, vinyl sulfonic acid, cyclohexane sulfonic acid, p-toluene sulfonic acid, p-phenol sulfonic acid, naphthalene sulfonic acid, benzene sulfonic acid, and camphor sulfonic acid. Among them, methanesulfonic acid is preferably used. The organic sulfonic acid-based catalyst may be used alone or in combination of at least 2 kinds.

When the organic sulfonic acid is used in the form of an aqueous solution, the concentration thereof may be preferably 0.05 to 2.0mol/L, more preferably 0.1 to 1.0mol/L.

< Mixed catalyst >)

The phosphoric acid-based catalyst and the organic sulfonic acid-based catalyst may be mixed and used as a mixed catalyst. The mixing ratio can be appropriately adjusted.

< Catalyst retention >

The catalyst is held in the feedstock sheet. The term "holding" as used herein means a state in which the catalyst is held in contact with the raw sheet, and may be in various forms such as adhesion, adsorption, impregnation, and the like. The method for holding the catalyst is not particularly limited, and examples thereof include: a method of immersing in an aqueous solution containing a catalyst, a method of scattering an aqueous solution containing a catalyst on a raw sheet, a method of contacting with vaporized catalyst vapor, a method of mixing fibers of a raw sheet in an aqueous solution containing a catalyst and papermaking, and the like.

From the viewpoint of sufficiently performing carbonization, the following method is preferably used: the sheet of raw material is impregnated with an aqueous solution containing a catalyst, and the catalyst is impregnated into the fibers. The temperature at the time of immersion in the aqueous solution containing the catalyst is not particularly limited, and is preferably room temperature. The dipping time is preferably 10 seconds to 120 minutes, more preferably 20 seconds to 30 minutes. The impregnation adsorbs, for example, 1 to 150 mass%, preferably 5 to 60 mass%, of the catalyst to the fibers constituting the raw sheet. After impregnation, the sheet of raw material is preferably taken out and dried. The drying method may be, for example, any method such as leaving at room temperature and introducing into a dryer. The drying is performed only by evaporating the remaining water after the catalyst is taken out of the aqueous solution containing the catalyst, and the weight of the sample is not changed. For example, the room temperature drying may be carried out by allowing the drying time to stand for 0.5 days or longer. After the drying to make the mass hardly changed, a step of carbonizing the raw sheet in which the catalyst is held is performed.

6-3 Carbonization treatment

After preparing the raw sheet with the catalyst held, it is subjected to carbonization treatment. The carbonization treatment for obtaining the activated carbon fiber sheet may be performed according to a usual carbonization method of activated carbon, and as a preferred embodiment, may be performed in the following manner.

Carbonization is generally performed in an inert gas atmosphere. In the present invention, the inert gas atmosphere is an oxygen-free or low-oxygen atmosphere in which carbon is less likely to undergo a combustion reaction and is carbonized, and may be preferably a gas atmosphere such as argon or nitrogen.

The raw sheet material holding the catalyst may be carbonized by heat treatment in the above-described predetermined gas atmosphere.

In one embodiment of the present invention, the heating temperature in the carbonization treatment may be preferably 300 to 1400 ℃. More specifically, as described below.

The lower limit of the heating temperature may be preferably 300℃or higher, more preferably 350℃or higher, still more preferably 400℃or higher or 750℃or higher.

The upper limit of the heating temperature may be preferably 1400 ℃ or less, more preferably 1300 ℃ or less, and still more preferably 1200 ℃ or less or 1000 ℃ or less.

By setting the heating temperature as described above, a carbon fiber sheet having a fiber form maintained can be obtained. When the heating temperature is not more than the lower limit, the carbon content of the carbon fiber is not more than 80%, and carbonization tends to be insufficient.

In one embodiment of the present invention, the heating treatment time in the carbonization treatment further includes a time for raising the temperature, and may be preferably 10 to 180 minutes. More specifically, as described below.

The lower limit of the heating treatment time also includes a time for raising the temperature, and may be preferably 10 minutes or more, more preferably 11 minutes or more, further preferably 12 minutes, 15 minutes, 20 minutes, 25 minutes or more, more preferably 30 minutes or more.

The upper limit of the heating treatment time is arbitrary, and may be preferably 180 minutes or less, more preferably 160 minutes, and still more preferably 140 minutes or less.

By sufficiently impregnating the raw sheet with the catalyst and setting the above-described preferable heating temperature and adjusting the heating treatment time, the degree of progress of pore formation can be adjusted, and the physical properties of the porous body, such as the specific surface area, the volumes of various pores, and the average pore diameter, can be adjusted.

If the heat treatment time is less than the lower limit, carbonization tends to be insufficient.

Further, as the heat treatment, after the heat treatment (sometimes referred to as a primary heat treatment) as described above, a reheating treatment may be further performed in a predetermined gas atmosphere. That is, the carbonization treatment may be performed in a plurality of stages by performing the heating treatment under different conditions such as temperature. By performing the primary heating treatment and the reheating treatment under predetermined conditions, physical properties may be adjusted, and carbonization and subsequent activation may be performed more favorably, thereby obtaining an activated carbon fiber sheet excellent in adsorption/desorption properties.

6-4 Activation treatment

In one embodiment of the present invention, as the activation treatment, for example, water vapor and carbon dioxide may be continuously supplied after the heating treatment and maintained at an appropriate activation temperature for a predetermined time, thereby obtaining an activated carbon fiber sheet.

In one embodiment of the present invention, the heating temperature in the activation treatment may be preferably 300 to 1400 ℃. More specifically, as described below.

The lower limit of the activation temperature may be preferably 300℃or higher, more preferably 350℃or higher, and still more preferably 400, 500, 600, 700 or 750℃or higher.

On the other hand, the upper limit of the activation temperature may be preferably 1400 ℃ or less, more preferably 1300 ℃ or less, and still more preferably 1200 or 1000 ℃ or less.

In the case where the activation treatment is continuously performed after the heat treatment, the temperature is preferably adjusted to be equal to the heat treatment temperature.

The lower limit of the activation time may be preferably 1 minute or more, more preferably 5 minutes or more.

The upper limit of the activation time may be any, and may be preferably 180 minutes or less, more preferably 160 minutes or less, and further preferably 140 minutes or less, 100 minutes or less, 50 minutes or less, and 30 minutes or less.

6-5 Production of molded article

The method for processing the molded article comprising the activated carbon fiber, the granular activated carbon, and the binder is not particularly limited, and the molded article can be obtained by, for example, preparing a mixture of both and molding the mixture. As one embodiment, for example, a molded body can be produced in the following manner.

Preparation of a slurry comprising activated carbon fibers, granular activated carbon and a Binder

The activated carbon fiber sheet and the binder prepared in advance are mixed in water, defibrated and dispersed by a mixer stirring mechanism, and both are mixed to obtain a slurry (slurry 1) containing both. The activated carbon fiber sheet to be put into the mixer may be put after being made into a small piece of an appropriate size according to the scale of the mixer or the like.

The granular activated carbon is further added to the 1 st slurry, and the granular activated carbon is mixed by using a stirring mechanism such as a doctor blade, whereby a slurry (2 nd slurry) containing activated carbon fibers, granular activated carbon, and a binder can be obtained. In dispersing the granular activated carbon, it is preferable to perform slow stirring with a spatula or the like so as not to crush the granular activated carbon.

< Formation of molded article >

The molded adsorbent can be obtained by flowing the 2 nd slurry obtained in the above manner and containing activated carbon fibers, granular activated carbon, and a binder into a mold of a desired shape, removing moisture while pressing, and drying the same.

< Manufacturing of layered adsorbent >

As another embodiment of the present invention, a molded adsorbent in which granular activated carbon is sandwiched between activated carbon fiber sheets can be produced, for example, as follows. First, an activated carbon fiber sheet is prepared. The granular activated carbon is attached to a main surface to which the activated carbon fiber sheets are bonded. For example, a mixed slurry containing granular activated carbon and a binder may be prepared, and the mixed slurry may be applied to the activated carbon fiber sheet, or a monomer slurry of granular activated carbon may be attached to the activated carbon fiber sheet first, and then a monomer slurry of a binder may be applied.

Examples

The present invention will be specifically described with reference to the following examples, but the technical scope of the present invention is not limited to the following examples.

Various items related to the physical properties and performances of the activated carbon fiber, the granular activated carbon, and the molded adsorbent were measured and evaluated by the following methods. The various values defining the present invention can be obtained by the following measurement methods and evaluation methods.

The basic physical properties related to the adsorption performance of JIS K1477 were referred to as reference standards for the N ₂ adsorption BET analysis method related to the specific surface area, the total pore volume, and the average pore diameter. Regarding the ultramicropore volume and the micropore volume, a simulation analysis method based on N ₂ adsorption GCMC (GCMC: grand Canonical Monte Carlo method: giant regularized Monte Carlo method) was used as a reference standard.

Specific surface area >

About 30mg of a sample for measurement (activated carbon fiber sheet, granular activated carbon, or molded adsorbent, hereinafter referred to as "the same shall") was collected, dried under vacuum at 200℃for 20 hours, weighed, and measured by a high-precision gas/vapor adsorption amount measuring device BELSORP-maxII (MicrotracBEL Corp.). The adsorption amount of nitrogen at the boiling point (77K) of liquid nitrogen was measured in the range of the relative pressure of the order of 10 ^-8 to 0.990, and the adsorption isotherm of the sample was prepared. The adsorption isotherm was analyzed by the BET method in which the analysis relative pressure range was automatically determined under the conditions of the adsorption isotherm type I (ISO 9277), and the BET specific surface area per unit weight (unit: m ²/g) was obtained and was used as the specific surface area (unit: m ²/g).

< Total pore volume >)

Based on the result of the isothermal adsorption line obtained from the above specific surface area term at a relative pressure of 0.960, the total pore volume (unit: cm ³/g) by the single-point method was calculated.

< Average pore diameter (average pore diameter) unit: nm >

Calculated by the following equation 3.

Average pore diameter=4×total pore volume×10 ³ ≡specific surface area ≡ · (formula 3)

< Ultramicropore volume >)

Analysis software BELMaster attached to the high-precision gas/vapor adsorption amount measurement apparatus BELSORP-maxII (MicrotracBEL corp.) was used to set the analysis settings to "Smoothing (moving average processing obtained at 1 point before and after each analysis point using pore distribution)", "distribution function: no hypothesis (No-assumption) "," definition of pore size: solid and liquid defined pore sizes (Solid and Fluid def. Pore Size) "," Kernel (Kernel): the isothermal Adsorption line obtained in the above specific surface area item was analyzed by the GCMC method of Slit-carbon-Adsorption (Slit-C-Adsorption), and the cumulative pore volume of 0.7nm was read as the ultramicropore volume (unit: cm ³/g) from the result of the pore distribution curve at the time of Adsorption obtained.

< Micropore volume >)

Analysis software BELMaster attached to the high-precision gas/vapor adsorption amount measurement apparatus BELSORP-maxII (MicrotracBEL corp.) was used to set the analysis settings to "Smoothing (moving average processing obtained at 1 point before and after each analysis point using pore distribution)", "distribution function: no hypothesis (No-assumption) "," definition of pore size: solid and liquid defined pore sizes (Solid and Fluid def. Pore Size) "," Kernel (Kernel): the isothermal Adsorption line obtained in the above specific surface area item was analyzed by the GCMC method of Slit-carbon-Adsorption (Slit-C-Adsorption), and the cumulative pore volume of 2.0nm was read as the micropore volume (unit: cm ³/g) from the result of the pore distribution curve at the time of Adsorption obtained.

< Weight per square meter of sheet >)

The sample for measurement (activated carbon fiber sheet, etc.) was allowed to stand at a temperature of 23.+ -. 2 ℃ and a relative humidity of 50.+ -. 5% for 12 hours or more, and the weight per square meter (unit: g/m ²) of the sheet was determined from the weight and the longitudinal and transverse dimensions.

< Sheet thickness >)

The measurement sample (activated carbon fiber sheet, etc.) was allowed to stand at a temperature of 23.+ -. 2 ℃ and a relative humidity of 50.+ -. 5% for 12 hours or more, and the sheet thickness (unit: mm) when a load of 0.3kPa was applied was measured using a digital small-sized side thickness gauge FS-60DS (Darong Seisakusho Co., ltd.).

< Sheet conditioning density: units: g/cm ³ >)

Calculated by the following equation 4.

Sheet Density = sheet weight per square meter/sheet thickness ≡10 ³ · (4)

< Sheet moisture >)

After a sample for measurement (such as an activated carbon fiber sheet) was allowed to stand at a temperature of 23.+ -. 2 ℃ and a relative humidity of 50.+ -. 5% for 12 hours or more, 0.5 to 1.0g of the sample was collected and dried at 115.+ -. 5 ℃ for 3 hours or more by a dryer, and the moisture (unit:%) was determined from the weight change at this time.

< Measurement of the size of the shaped adsorbent >

The size of the molded adsorbent is obtained by measuring the size using a vernier caliper, a gauge, or the like. The dry weight of the molded adsorbent was measured by an electronic balance.

< Dry Density of the shaped adsorbent: units: g/cm ³ >)

Calculated by the following equation 5.

Density = dry weight of shaped adsorbent ≡volume (formula 5)

The volume of the molded adsorbent is calculated from the dimensional measurement of the molded adsorbent.

N-butane adsorption Desorption Performance

The concentration, flow rate, and flow rate of the desorption air of n-butane gas were individually set with reference to american society of test materials standard Standard Test Method for Determination of Butane Working Capacity of Activated Carbon(ASTM D5228-16),, and the test was performed.

Drying the molded adsorbent at 115+ -5deg.C for 3 hr or more with a dryer, cooling, and measuring dry weight. After measuring the mass of an empty adsorbent (a stainless steel shell container having the same cross-sectional shape as the molded adsorbent and allowing gas to flow therethrough), the molded adsorbent was filled in the adsorbent.

Next, the test tube was placed in a flow-through apparatus, and n-butane gas diluted with air to a concentration of 0.2% was flowed into the test tube at 1.0L/min at a test temperature of 25 ℃ to adsorb n-butane. The test tube was removed from the flow-through apparatus and the mass was measured. This 0.2% concentration n-butane flow was repeated until a constant mass was reached, i.e., until the adsorption capacity was saturated.

The test tube was replaced in the flow-through apparatus and air was flowed at 20.0L/min in the test tube for 12 minutes at the test temperature of 25℃to desorb n-butane. The test tube was removed from the flow-through apparatus and the mass was measured.

< Measurement of 0ppm maintenance time >

The concentration changes of adsorption and desorption at this n-butane flow were measured every 6 seconds using a portable gas detector Cosmotector (model: XP-3160, manufacturer: new Cosmos Electric Co., ltd.).

After repeating the first adsorption and desorption, the concentration change of the second adsorption was set to 0ppm below the lower limit of the quantitative determination (25 ppm), and the time for which 0ppm was maintained from the beginning was set to 0ppm maintenance time (minutes).

The operations of adsorption and desorption were repeated 2 times in total, and the first adsorption amount, the effective adsorption/desorption amount rate, and the effective adsorption/desorption rate were calculated using the following formulas 6, 7, 8, and 9.

< 6 >

First adsorption amount = first n-butane adsorption amount

The units of the respective numerical values are as follows.

First time n-butane adsorption quantity (unit: g)

< 7 >

Effective adsorption/desorption amount= (second n-butane adsorption amount+second n-butane desorption amount)/(2) the unit of each value is as follows.

Effective adsorption and desorption amount (unit: g)

Second n-butane adsorption quantity (unit: g)

Second n-butane desorption amount (unit: g)

< 8 >

Effective adsorption/desorption amount ratio = effective adsorption/desorption amount ≡molded adsorbent dry weight×100

The units of the respective numerical values are as follows.

Effective adsorption and desorption rate (unit: wt%)

Effective adsorption and desorption amount (unit: g)

Dry weight of formed adsorbent (unit: g)

< 9 >

Effective adsorption/desorption rate=effective adsorption/desorption amount/first adsorption amount×100

The units of the respective numerical values are as follows.

Effective adsorption and desorption rate (unit:%)

Effective adsorption and desorption amount (unit: g)

First adsorption quantity (unit: g)

< Measurement of pressure loss >)

Each molded adsorbent of examples, reference examples and comparative examples was prepared. As a container for accommodating the molded adsorbent, a case (case container) is prepared, which is a cylindrical container, one end face and the other end face are opened, respectively, and ventilation is possible in a direction orthogonal to the end faces. A case vessel having a diameter (inner diameter) of 6.2cm (i.e., an area of an opening surface: 30.18cm ²) was prepared for each end surface. The prepared molded adsorbent was filled inside the shell container so as not to generate a gap, and the molded adsorbent was used as a test sample for measuring the pressure loss.

The pressure loss was measured in the following manner. 60L/min of air was circulated through the test sample prepared as described above, and the differential pressure between the inlet and outlet of the test sample was measured using a Testo differential pressure meter (Testo Ltd.) to obtain the result as a pressure loss (kPa).

Production of activated carbon fiber sheet material (M1)

A needled nonwoven fabric having a weight per square meter of 400g/m ², which is formed from rayon fibers (17 dtex, a fiber length of 76 mm), is impregnated with a 6-10% aqueous solution of diammonium hydrogen phosphate, extruded with a liquid, and dried to be attached with 8-10% by weight. The resulting pretreated nonwoven fabric was heated to 900℃for 40 minutes in a nitrogen atmosphere, and kept at that temperature for 3 minutes. Then, at this temperature, activation treatment was performed for 17 minutes in a nitrogen gas stream containing water vapor having a dew point of 71 ℃.

Production of activated carbon fiber (M2)

6-10% Aqueous solution of diammonium hydrogen phosphate was impregnated into a web-like rayon fiber (56 dtex, fiber length 102 mm) having a weight of 400g/m ² per square meter by a carding machine, and the resultant was dried after extruding the liquid so as to be attached to 8-10% by weight. The resulting pretreated fibers were warmed to 900 ℃ for 45 minutes in a nitrogen atmosphere and held at that temperature for 3 minutes. Then, at this temperature, activation treatment was performed for 17 minutes in a nitrogen gas stream containing water vapor having a dew point of 71 ℃.

Reference example 1 (activated carbon fiber: granular activated carbon=100:0) >

5 Parts by weight (0.28 g) of Japan Exlan co., ltd. Acrylic fiber 50TWF as a fibrous binder was charged into a mixer together with 0.5L of water for 30 seconds to be defibrated and dispersed, and then 100 parts by weight (5.60 g) of the activated carbon fiber sheet obtained in the above (M1) and 0.5L of water were added to be defibrated and dispersed for 10 seconds to obtain a slurry in which defibrated activated carbon fibers were dispersed (slurry 1). A metal cylinder having an inner diameter of 63mm and a height of 400mm, which can be divided at a position 18mm from the bottom, was placed on a funnel provided with a perforated plate for suction dehydration, and the 1 st slurry was poured into the metal cylinder, and then suction dehydration was performed from the bottom to mold. The bottom 18mm of the molded body having the wet state enclosed therein was separated from the metal cylinder, the upper and lower cross sections of the metal cylinder were held by a punching plate, a weight of 1kg was placed, the molded body was dried at 120℃for 4 hours while being pressed to a height of 18mm, and then the metal cylinder was removed to obtain 5.80g of a disc-shaped adsorbent molded to have an outer diameter of 62mm and a height of 18 mm. The obtained molded adsorbent is less likely to undergo shape collapse than an activated carbon fiber sheet.

Reference example 2 (activated carbon fiber: granular activated carbon=100:0) >

A molded adsorbent having an outer diameter of 62mm and a height of 18mm was obtained in the same manner as in reference example 1 except that 5 parts by weight (0.28 g) of the fibrous binder used in reference example 1 was used, 100 parts by weight (5.61 g) of the activated carbon fiber sheet (M1) used in reference example 1 was used. The obtained molded adsorbent is less likely to undergo shape collapse than activated carbon fibers.

Example 1 (activated carbon fiber: granular activated carbon=90:10) >

5 Parts by weight (0.28 g) of the fibrous binder used in reference example 1 was charged into a mixer together with 0.5L of water for 30 seconds to effect defibration and dispersion, and then 90 parts by weight (5.04 g) of the activated carbon fiber sheet used in reference example 1 and 0.5L of water were added to effect defibration and dispersion for 10 seconds to obtain a 1 st slurry.

Next, 10 parts by weight (0.56 g) of granular activated carbon (specific surface area: 1660m ²/g, average particle diameter: 502 μm, standard deviation: 89 μm) was added to the 1 st slurry, and the mixture was stirred with a spatula to obtain a2 nd slurry in which activated carbon fibers and granular activated carbon were dispersed. The 2 nd slurry was dehydrated by suction and dried in the same manner as in example 1 to obtain 5.85g of a disc-shaped molded adsorbent having an outer diameter of 62mm and a height of 18 mm. The obtained molded adsorbent sheet is less likely to undergo shape collapse than activated carbon fibers.

Example 2 (activated carbon fiber: granular activated carbon=70:30) >

A molded adsorbent having an outer diameter of 62mm and a height of 18mm was obtained in the same manner as in example 1, except that the fibrous binder used in example 1 was 5 parts by weight (0.28 g), the activated carbon fiber sheet used in example 1 was 70 parts by weight (3.91 g), and the granular activated carbon used in example 1 was 30 parts by weight (1.68 g). The obtained molded adsorbent is less likely to undergo shape collapse than an activated carbon fiber sheet.

Example 3 (activated carbon fiber: granular activated carbon=60:40) >

5.80G of a molded adsorbent having an outer diameter of 62mm and a height of 18mm was obtained in the same manner as in example 1, except that 5 parts by weight (0.28 g) of the fibrous binder used in example 1, 60 parts by weight (3.37 g) of the activated carbon fiber sheet used in example 1, and 40 parts by weight (2.25 g) of the granular activated carbon used in example 1 were used. The obtained molded adsorbent is less likely to undergo shape collapse than an activated carbon fiber sheet.

Example 4 (activated carbon fiber: granular activated carbon=50:50) >

5.99G of a molded adsorbent having an outer diameter of 62mm and a height of 18mm was obtained in the same manner as in example 1, except that the fibrous binder used in example 1 was 5 parts by weight (0.29 g), the activated carbon fiber sheet used in example 1 was 50 parts by weight (2.88 g), and the granular activated carbon used in example 1 was 50 parts by weight (2.88 g). The obtained molded adsorbent is less likely to undergo shape collapse than an activated carbon fiber sheet.

Example 5 (activated carbon fiber: granular activated carbon=30:70) >

A2 nd slurry was obtained in the same manner as in example 1, except that the fibrous binder used in example 1 was 5 parts by weight (0.29 g), the activated carbon fiber sheet used in example 1 was 30 parts by weight (1.71 g), and the granular activated carbon used in example 1 was 70 parts by weight (4.00 g).

A metal cylinder having an inner diameter of 63mm and a height of 400mm, which can be divided at a position 18mm from the bottom, was placed on a funnel provided with a perforated plate for suction dehydration, and the 2 nd slurry was poured into the metal cylinder, and then suction dehydration was performed from the bottom to mold. The bottom of the molded article having the wet state enclosed therein was separated from the metal cylinder by 18mm, and after drying at 120℃for 4 hours, the metal cylinder was removed to obtain 5.89g of a molded adsorbent having an outer diameter of 62mm and a height of 16 mm. The obtained molded adsorbent is less likely to undergo shape collapse than an activated carbon fiber sheet.

Example 6 (activated carbon fiber: granular activated carbon=10:90) >

6.00G of a molded adsorbent having an outer diameter of 62mm and a height of 10mm was obtained in the same manner as in example 5, except that the fibrous binder used in example 1 was 5 parts by weight (0.29 g), the activated carbon fiber sheet used in example 1 was 10 parts by weight (0.58 g), and the granular activated carbon used in example 1 was 90 parts by weight (5.22 g). The obtained molded adsorbent is less likely to undergo shape collapse than an activated carbon fiber sheet.

Example 7 (activated carbon fiber: granular activated carbon=60:40) >

A molded adsorbent having an outer diameter of 62mm and a height of 18mm was obtained in the same manner as in example 1, except that 5 parts by weight (0.28 g) of the fibrous binder used in example 1, 60 parts by weight (3.37 g) of the activated carbon fiber sheet used in example 1, 40 parts by weight (2.25 g) of the granular activated carbon (specific surface area: 1860m ²/g, average particle diameter: 269 μm, standard deviation: 65 μm) was used in example 1. The obtained molded adsorbent is less likely to undergo shape collapse than an activated carbon fiber sheet.

Example 8 (activated carbon fiber: granular activated carbon=90:10) >

A molded adsorbent having an outer diameter of 62mm and a height of 18mm was obtained in the same manner as in example 1, except that the fibrous binder used in example 1 was 5 parts by weight (0.28 g), the activated carbon fiber sheet (M1) used in example 1 was 90 parts by weight (5.04 g) of activated carbon fiber (M2), and the granular activated carbon used in example 1 was 10 parts by weight (0.56 g). The obtained molded adsorbent is less likely to undergo shape collapse than activated carbon fibers.

Example 9 (activated carbon fiber: granular activated carbon=60:40) >

A molded adsorbent having an outer diameter of 62mm and a height of 18mm was obtained in the same manner as in example 1 except that 5 parts by weight (0.28 g) of the fibrous binder used in example 1, 60 parts by weight (3.37 g) of the activated carbon fiber sheet (M1) used in example 1, and 40 parts by weight (2.25 g) of the granular activated carbon used in example 1 were used. The obtained molded adsorbent is less likely to undergo shape collapse than activated carbon fibers.

Example 10 (activated carbon fiber: granular activated carbon=10:90) >

A molded adsorbent having an outer diameter of 62mm and a height of 10mm was obtained in the same manner as in example 5 except that the fibrous binder used in example 1 was 5 parts by weight (0.28 g), the activated carbon fiber sheet (M1) used in example 1 was 10 parts by weight (0.57 g) of activated carbon fiber (M2), and the granular activated carbon used in example 1 was 90 parts by weight (5.03 g). The obtained molded adsorbent is less likely to undergo shape collapse than activated carbon fibers.

Comparative example 1 (activated carbon fiber: granular activated carbon=0:100) >

5 Parts by weight (0.32 g) of the dimensional binder used in example 1 was charged into a mixer together with 0.5L of water for 30 seconds to effect defibration and dispersion, followed by addition of 100 parts by weight (6.43 g) of the granular activated carbon used in example 1 and 0.5L of water, and stirring with a spatula to obtain a granular activated carbon adsorption slurry. The slurry for adsorption was dehydrated by suction and dried in the same manner as in example 5 to obtain 6.71g of a disk-shaped molded adsorbent having an outer diameter of 62mm and a height of 6 mm.

Comparative example 2 (activated carbon fiber: granular activated carbon=0:100) >

A disc-shaped molded adsorbent 6.62g having an outer diameter of 62mm and a height of 7mm was obtained in the same manner as in comparative example 1 except that 100 parts by weight (6.30 g) of granular activated carbon (specific surface area: 1860m ²/g, average particle diameter: 269 μm, standard deviation: 65 μm) was used as the granular activated carbon used in comparative example 1.

The measured values of the adsorbents for examples 1 to 10, reference examples 1 and 2, and comparative examples 1 and 2 were obtained by the above measurement methods for the physical property items. The results are shown in Table 1. The properties of the molded adsorbents of examples 1 to 10, reference examples 1 and 2, and comparative examples 1 and 2 are shown in tables 2-1, 2-2, 2-3, 3-1, 3-2, and 3-3, respectively. In the table, the term "ACF" is a shorthand for the activated carbon fiber (ACTIVATED CARBON FIBER).

TABLE 1

[ Table 2-1]

[ Table 2-2]

[ Tables 2 to 3]

[ Table 3-1]

[ Table 3-2]

[ Tables 3-3]

As shown in tables 3-1, 3-2 and 3-3, the molded adsorbent comprising activated carbon fibers and granular activated carbon was excellent in adsorption/desorption properties, and a molded adsorbent having a low pressure loss was obtained.

Description of the reference numerals

1: Laminated adsorbent, 10: sheet-shaped molded adsorbent, 10a: main surface of sheet-shaped adsorbent, 10b: side end face of sheet-shaped molded adsorbent, 10c: side end face of sheet-shaped molded adsorbent, F: flow direction of gas, 2: disc-shaped molded adsorbent, 3: a cylindrical molded adsorbent.

Claims

1. A molded adsorbent for an adsorption tank,

In the total amount of the activated carbon fibers and the granular activated carbon, the weight ratio of the activated carbon fibers to the granular activated carbon is 5 to 95 parts by weight of the activated carbon fibers and 95 to 5 parts by weight of the granular activated carbon,

The weight ratio of the binder in the molded adsorbent is 0.3 to 20 parts by weight relative to 100 parts by weight of the content of the activated carbon fibers and the granular activated carbon.

2. The molded adsorbent according to claim 1, wherein a pressure loss of the molded adsorbent is smaller than either a pressure loss of a molded body of the two mixtures of the activated carbon fiber and the binder or a pressure loss of a molded body of the two mixtures of the granular activated carbon and the binder.

3. The molded adsorbent for a canister according to claim 2, wherein the pressure loss of the molded adsorbent is 0.52kPa or less.

4. The molded adsorbent for a canister according to claim 2, wherein the pressure loss of the molded adsorbent is 0.45kPa or less.

5. A shaped adsorbent according to claim 1, wherein the granular activated carbon has an average particle size of 100 to 3000 μm.

6. A shaped adsorbent according to claim 1, wherein the activated carbon fibers have an average fiber length of 300 to 10000 μm.

7. A shaped adsorbent according to claim 1, wherein the shaped adsorbent has a dry density of 0.010 to 0.400g/cm ³.

8. A shaped adsorbent according to claim 1, wherein the shaped adsorbent has a specific surface area of 2500m ²/g or less.

9. A shaped adsorbent according to claim 1, wherein the total pore volume of the shaped adsorbent is from 0.50 to 1.20cm ³.

10. A shaped adsorbent according to claim 1, wherein the binder is a fibrous binder.

11. The molded adsorbent according to claim 1, wherein the granular activated carbon has an average particle diameter of 100 to 3000 μm,

The average fiber length of the activated carbon fiber is 300-10000 mu m,

The drying density of the formed adsorbent is 0.010-0.400 g/cm ³,

The specific surface area of the molded adsorbent is 2500m ²/g or less,

The total pore volume of the molded adsorbent is 0.50-1.20 cm ³, and

The binder is a fibrous binder.

12. A molded adsorbent as claimed in claim 3, wherein the granular activated carbon has an average particle diameter of 100 to 3000 μm,

The average fiber length of the activated carbon fiber is 300-10000 mu m,

The drying density of the formed adsorbent is 0.010-0.400 g/cm ³,

The specific surface area of the molded adsorbent is 2500m ²/g or less,

The total pore volume of the molded adsorbent is 0.50-1.20 cm ³, and

The binder is a fibrous binder.

13. An adsorption tank provided with the molded adsorbent according to any one of claims 1 to 12.