JP7107801B2 - Method for producing activated carbon fiber material - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing an activated carbon fiber material, and more particularly to a method for producing an activated carbon fiber material using a cellulosic material as a raw material.

Carbon fiber is lightweight, has excellent strength, electrical conductivity, heat resistance, and chemical resistance, and is widely used in sports and leisure goods, aerospace, and industrial applications. In this field, fabrics woven from tows of polyacrylonitrile (PAN)-based carbon fibers or pitch-based carbon fibers are generally used. is one of the obstacles to widespread use.

Therefore, attention has been focused on carbon materials made from cheap cellulosic substances, which are the largest biomass on earth. Originally, as a carbon fiber made from a cellulosic material, the UCC Company in the United States started to produce it using a rayon-based carbon fiber. However, at first, there was a problem that the carbonization yield decreased due to thermal decomposition of cellulose.

A method using sulfonic acid as a carbonization catalyst has been disclosed as a method for producing a cellulosic material in high yield while maintaining the form of the cellulosic material (Patent Document 1).

Further, Patent Document 2 discloses a method of carbonizing a cellulose-based material using a phosphorus compound-based catalyst.

WO2013/183668 JP-A-50-148627

As described above, research and development have been devoted to reducing manufacturing costs and improving carbon fiber materials using cellulosic materials. , performance, and manufacturing cost, further improvements are required. Conventionally, it has been difficult to increase the residual ratio or the total yield after heat treatment when trying to obtain an activated carbon fiber material with high adsorptivity. If the residual ratio after carbonization treatment is low, the total yield of the activated carbon fiber material finally obtained through activation tends to be low, so it is desirable to be able to produce with as high a residual ratio as possible.

In view of the above circumstances, the present invention aims to solve the problem of producing an activated carbon fiber material with excellent adsorptivity from a cellulosic material with a higher overall yield or residual rate than before. be. In the description of the present invention, the term "total yield" refers to the percentage by weight of the activated carbon fiber material precursor, and the term "residual rate" refers to the amount of the carbon fiber material that has not been activated. Represents the thermal weight residual rate %.

As a result of extensive research, the present inventors have found that by using both an organic sulfonic acid-based catalyst and a phosphoric acid-based catalyst, an activated carbon fiber material having excellent adsorption performance can be obtained with a higher total yield or residual rate than before. The present invention was completed by discovering that it can be produced by That is, the present invention provides the following manufacturing method.

[1] including carbonizing and activating a cellulose-based material holding a mixed catalyst containing an organic sulfonic acid-based catalyst and a phosphoric acid-based catalyst in an inert gas atmosphere;
The weight ratio of the organic sulfonic acid-based catalyst and the phosphoric acid-based catalyst contained in the mixed catalyst is 10:90 to 90:10.
A method for producing an activated carbon fiber material.
[2] The activated carbon fiber material according to [1] above, which includes carbonizing the cellulosic material at a temperature of 450 to 1300° C. and activating it at a temperature of 750 to 1200° C. Production method.
[3] The above [ The method for producing an activated carbon fiber material according to 1] or [2].
[4] The above, wherein the phosphoric acid-based catalyst is one or more selected from the group consisting of phosphoric acid, ammonium dihydrogen phosphate, diammonium hydrogen phosphate, triammonium phosphate, and guanidine phosphate. [1] A method for producing an activated carbon fiber material according to any one of [3].
[5] The method for producing an activated carbon fiber material according to any one of [1] to [4] above, wherein the cellulosic material contains regenerated cellulose fibers derived from wood or cotton.

According to the present invention, an activated carbon fiber material with excellent adsorptive properties can be produced with a high total yield or residual rate.

Embodiments of the present invention will be described below. In addition, unless otherwise specified, the description "AA to BB" with respect to the numerical range indicates "AA or more and BB or less" (here, "AA" and "BB" indicate arbitrary numerical values).

1. Preparation of raw material (precursor) <Cellulosic material>
In the manufacturing method of the present invention, a cellulosic material is used as a raw material. The cellulosic material is a material containing cellulose and/or a derivative thereof as a main component, and may be of any origin, such as chemically synthesized products, plant-derived cellulose, regenerated cellulose, and cellulose produced by bacteria, preferably. Those derived from wood, cotton, etc. may be used. As the form of the cellulose material, a fibrous one can be preferably used.

<Cellulose fiber>
Cellulosic fibers are fibers composed mainly of cellulose and/or its derivatives. Cellulosic fibers are preferably, for example, fibers formed from plant cellulosic substances obtained from trees (or wood) and cotton, and plant cellulosic substances (cotton, pulp, etc.) are dissolved by chemical treatment. For example, fibers composed of long fibrous regenerated cellulosic materials obtained by the method can be used. In addition, the fibers may contain components such as lignin and hemicellulose.

Examples of cellulosic fibers (plant-based cellulose materials, regenerated cellulose materials) include cotton (short-fiber cotton, medium-fiber cotton, long-fiber cotton, extra-long staple, extra/super-long staple, etc.), hemp, bamboo, and kozo. vegetable cellulose fibers such as , mitsumata, bananas, and tunic; N-oxide) spun refined cellulose fibers such as lyocell; and acetate fibers such as diacetate and triacetate. Among these, at least one selected from cuprammonium rayon, viscose method rayon, and refined cellulose fiber is preferable because of its easy availability.

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

The form of the cellulosic fiber is not particularly limited, and it is possible to use those prepared into raw yarn (unprocessed yarn), false twisted yarn, dyed yarn, single yarn, plied yarn, covering yarn, etc. according to the purpose. can be done. Moreover, when the cellulosic fiber contains two or more kinds of raw materials, it may be a blended yarn, a blended twisted yarn, or the like. Furthermore, as the cellulosic fiber, the raw materials in various forms described above may be used singly or in combination of two or more. Among these, non-twisted yarn is preferable from the standpoint of compatibility between moldability and mechanical strength of the composite material.

<Fiber sheet>
The raw material may be a fiber sheet processed into a sheet using the fibers described above. A fiber sheet refers to a product obtained by processing a large number of fibers into a thin and wide sheet, and includes woven fabrics, knitted fabrics, non-woven fabrics, and the like.

The method of weaving the cellulosic fiber is not particularly limited, and a general method can be used, and the weave structure of the fabric is also not particularly limited, and the three original structures of plain weave, twill weave, and satin weave can be used.

In the woven fabric formed of cellulosic fibers, the gap between the warps and wefts of the cellulosic fibers is preferably 0.1 to 0.8 mm, more preferably 0.2 to 0.6 mm, and even more preferably. 0.25 to 0.5 mm. Furthermore, the fabric made of cellulosic fibers preferably has a basis weight of 50 to 400 g/m ² , more preferably 100 to 300 g/m ² .

By setting the content of the cellulosic fiber and the fabric composed of the cellulosic fiber within the above range, the carbon fiber fabric obtained by heat-treating this fabric can have excellent strength.

The method for producing the nonwoven fabric is not particularly limited, but for example, a method of obtaining a fiber sheet by using the above-mentioned fiber cut to an appropriate length as a raw material by a dry method or a wet method, or by using an electrospinning method or the like. A method of obtaining a fiber sheet directly from a solution, etc. can be mentioned. Furthermore, after the nonwoven fabric is obtained, a treatment such as resin bond, thermal bond, spunlace, needle punch, or the like may be added for the purpose of bonding the fibers together.

2. Retention of Catalyst The raw material prepared as described above is made to retain the catalyst. An activated porous activated carbon fiber material can be obtained by allowing the raw material to retain the catalyst and performing a predetermined heat treatment or the like. As the catalyst, a mixed catalyst of an organic sulfonic acid-based catalyst and a phosphoric acid-based catalyst is used.

<Organic sulfonic acid catalyst>
As the organic sulfonic acid, an organic compound having one or more sulfo groups can be used. For example, compounds having a sulfo group bonded to various carbon skeletons such as aliphatic and aromatic compounds can be used. From the viewpoint of handling, the organic sulfonic acid catalyst preferably has a low molecular weight.

Examples of organic sulfonic acid-based catalysts include R—SO ₃ H (wherein R is a linear/branched alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, or a carbon represents an aryl group having 6 to 20 atoms, and the alkyl group, cycloalkyl group, and aryl group may be substituted with an alkyl group, a hydroxyl group, and a halogen group, respectively.). Examples of organic sulfonic acid catalysts include methanesulfonic acid, ethanesulfonic acid, propanesulfonic acid, 1-hexanesulfonic acid, vinylsulfonic acid, cyclohexanesulfonic acid, p-toluenesulfonic acid, p-phenolsulfonic acid, and naphthalenesulfone. acid, benzenesulfonic acid, camphorsulfonic acid and the like. Among these, methanesulfonic acid, p-toluenesulfonic acid, naphthalenesulfonic acid, benzenesulfonic acid, and camphorsulfonic acid are preferably used, and methanesulfonic acid is more preferably used. Moreover, the organic sulfonic acid-based catalyst may be used alone or in combination of two or more.

When the organic sulfonic acid is used as an aqueous solution, its concentration is preferably 0.05 to 2.00 mol/L, more preferably 0.10 to 1.00 mol/L.

<Phosphoric acid catalyst>
Phosphoric acid catalysts include, for example, phosphoric acid, metaphosphoric acid, pyrophosphoric acid, phosphorous acid, phosphonic acid, phosphonous acid, oxyacids of phosphorus such as phosphinic acid, ammonium dihydrogen phosphate, diammonium hydrogen phosphate, triammonium phosphate, guanidine phosphate, dimethylphosphonopropanamide, ammonium polyphosphate, polyphosphonitrile chloride, and phosphoric acid, tetrakis(hydroxymethyl)phosphonium salts or tris(1-aziridinyl)phosphine oxide and urea, thiourea, melamine, guanine, cyanamide, hydrazine, dicyandiamide, or condensation products thereof with methylol derivatives; Among these, phosphoric acid, ammonium dihydrogen phosphate, diammonium hydrogen phosphate, triammonium phosphate, and guanidine phosphate can be preferably used, and diammonium hydrogen phosphate can be used more preferably. The phosphoric acid-based catalyst may be used alone or in combination of two or more.

When the phosphoric acid catalyst is used as an aqueous solution, its concentration is preferably 0.05 to 2.00 mol/L, more preferably 0.1 to 1.0 mol/L.

<Mixed catalyst>
In the production method of the present invention, an organic sulfonic acid-based catalyst and a phosphoric acid-based catalyst are mixed and used as a mixed catalyst. The combination of the organic sulfonic acid-based catalyst and the phosphoric acid-based catalyst can be arbitrary, but preferably one or more of the above-exemplified organic sulfonic acid-based catalysts and phosphoric acid-based catalysts are selected. More preferably, a mixed catalyst of methanesulfonic acid and diammonium hydrogen phosphate is exemplified.

When the mixing ratio of the organic sulfonic acid-based catalyst and the phosphoric acid-based catalyst in the mixed catalyst is represented by the weight ratio when the total weight of both is 100, the mixed weight of the organic sulfonic acid-based catalyst and the phosphoric acid-based catalyst The ratio can be adjusted in the range of 10:90 to 90:10 (in other words, organic sulfonic acid catalyst:phosphoric acid catalyst=10 to 90:90 to 10).

The lower limit of the weight ratio of the organic sulfonic acid catalyst is preferably 10 or more, more preferably 15 or more, and even more preferably 20 or more.
The upper limit of the weight ratio of the organic sulfonic acid catalyst is preferably 90 or less, more preferably 85 or less, still more preferably 80, 70, 60, 50, 40 or 30 or less.

On the other hand, the lower limit of the weight ratio of the paired phosphoric acid catalyst is preferably 10 or more, more preferably 15 or more, and even more preferably 20, 30, 40, 50, 60 or 70 or more.
The upper limit of the weight ratio of the phosphoric acid catalyst is preferably 90 or less, more preferably 85 or less, still more preferably 80 or less.

By setting the mixing weight ratio within the above range, an activated carbon fiber material with excellent adsorption performance can be produced with a higher overall yield or residual rate than conventionally. Further, by setting the weight ratio of the organic sulfonic acid-based catalyst to a lower value within the preferred range described above, the pH of the mixed catalyst solution can be set closer to neutral while maintaining an improvement in the total yield or residual rate. Therefore, the mixed catalyst solution can be made easy to handle, which is a great advantage in the production process.

The mixed catalyst can be used as an aqueous solution.
The lower limit of the mixed catalyst concentration in the mixed catalyst aqueous solution is preferably 1% (W/V) or more, more preferably 2% (W/V) or more, and still more preferably 3% (W/V) or more.
The upper limit of the mixed catalyst concentration in the mixed catalyst aqueous solution is preferably 20% (W/V) or less, more preferably 18% (W/V) or less, and even more preferably 15% (W/V) or less.

<Retention of catalyst>
Hold the catalyst against the raw material. Here, "holding" means keeping the catalyst in contact with the raw material, and can take various forms such as adhesion, adsorption, and impregnation. The method for holding the catalyst is not particularly limited, but for example, a method of immersing in an aqueous solution containing the catalyst, a method of sprinkling the aqueous solution containing the catalyst over the raw material, a method of contacting with vaporized catalyst vapor, and an aqueous solution containing the catalyst. A method of making paper by mixing the raw material fiber into the paper.

From the viewpoint of sufficient activation, preferably, a method of immersing the raw material in an aqueous solution containing the catalyst and impregnating the inside of the fiber with the catalyst can be used. The temperature at which the substrate is immersed in the aqueous solution containing the catalyst is not particularly limited, but room temperature is preferable. The immersion time is preferably 10 seconds to 120 minutes, more preferably 20 seconds to 30 minutes. By immersion, for example, 1 to 150% by mass, preferably 5 to 60% by mass, of the catalyst is adsorbed on the fibers constituting the raw material. After soaking, the raw material is preferably removed and dried. As a drying method, any method such as leaving at room temperature or introducing into a dryer may be used. After the sample is removed from the aqueous solution containing the catalyst, drying may be carried out until excess moisture evaporates and the sample weight does not change. For example, in room temperature drying, the drying time may be left for 0.5 days or longer. After almost no change in mass due to drying, the process proceeds to the step of carbonizing the raw material holding the catalyst.

3. Carbonization Treatment After preparing the raw material with the catalyst retained, it is carbonized. The carbonization treatment for obtaining the activated carbon fiber material can be carried out according to a general carbonization method for activated carbon, and in a preferred embodiment, it can be carried out as follows.

Carbonization treatment is usually performed in an inert gas atmosphere. In the present invention, the inert gas atmosphere means an oxygen-free or low-oxygen atmosphere in which carbon hardly undergoes a combustion reaction and is carbonized, and is preferably a gas atmosphere such as argon or nitrogen.

The raw material holding the catalyst is heat-treated and carbonized in the predetermined gas atmosphere described above.

The lower limit of the heating temperature is preferably 450°C or higher, more preferably 500°C or higher, and still more preferably 600, 700, 800, or 850°C or higher.
The upper limit of the heating temperature is preferably 1,300° C. or lower, more preferably 1,200° C. or lower, and still more preferably 1,100, 1,000, or 950° C. or lower.
By setting the heating temperature in this manner, a carbon fiber material in which the fiber form is maintained can be obtained. If the heating temperature is equal to or lower than the above lower limit, the carbon content of the carbon fibers is 80% or lower, and carbonization tends to be insufficient.

The lower limit of the heat treatment time, including the temperature rising time, is preferably 10 minutes or longer, more preferably 11 minutes or longer, still more preferably 12 minutes or longer, and more preferably 25 minutes or longer.
Although the upper limit of the heat treatment time can be arbitrary, it is preferably 180 minutes or less, more preferably 160 minutes, and still more preferably 100 or 50 minutes.
By sufficiently impregnating the raw material with the catalyst, setting the above suitable heating temperature, and adjusting the heat treatment time, the progress of pore formation can be adjusted, and the specific surface area, the volume of various pores, Physical properties of the porous body such as average pore diameter can be adjusted. When the heat treatment time is shorter than the above lower limit, carbonization tends to be insufficient.

As the heat treatment, after the above heat treatment (sometimes referred to as primary heat treatment), reheat treatment can be further performed in a predetermined gas atmosphere. That is, the carbonization treatment may be performed by dividing the heat treatment with different conditions such as temperature into a plurality of stages. By performing the primary heat treatment and reheat treatment under predetermined conditions, it may be possible to adjust the physical properties, promote the activation more favorably, and obtain an activated carbon fiber material with excellent adsorption and desorption properties. .

4. Activation Treatment The activation treatment in the present invention can be carried out, for example, by continuously supplying water vapor after the heat treatment and maintaining an appropriate activation temperature for a predetermined period of time to obtain an activated carbon fiber material. .

The lower limit of the activation temperature is preferably 750°C or higher, more preferably 800°C or higher, and even more preferably 850 or 900°C or higher.
On the other hand, the upper limit of the activation temperature is preferably 1200° C. or lower, more preferably 1100° C. or lower, and even more preferably 1000 or 950° C. or lower.
When the activation treatment is performed continuously after the heat treatment, it is desirable to adjust the temperature to the same level as the heat treatment temperature.

The lower limit of the activation time is preferably 1 minute or longer, more preferably 3 minutes or longer, and still more preferably 5 minutes or longer.
Although the upper limit of the activation time can be arbitrary, it is preferably 180 minutes or less, more preferably 160 minutes or less, and still more preferably 140, 100, 50, 30 or 15 minutes or less.

According to the production method of the present invention, activated carbon fibers with excellent adsorptivity can be produced with a higher total yield or residual rate than conventional ones. The production method of the present invention is suitable, for example, for producing activated carbon fibers having the following physical properties or adsorptive properties.

<Total pore volume>
An activated carbon fiber material having a total pore volume with a lower limit of 0.30 or 0.40 cm ³ /g or more and an upper limit of less than 1.00 or 0.70 cm ³ /g.

<Average pore diameter>
An activated carbon fiber material having an average pore diameter with a lower limit of 1.55 or 1.57 nm or more and an upper limit of 2.00, 1.80, or 1.72 nm or less.

<Methylene blue adsorption performance>
An activated carbon fiber material having a methylene blue adsorption performance of 100, 150, 160, 190, or 220 or more ml/g.

<Iodine adsorption performance>
An activated carbon fiber material having an iodine adsorption capacity of preferably 400 mg/g or more, more preferably 600 mg/g or more, and even more preferably 800 or 1000 mg/g or more.

According to the production method of the present invention, an activated carbon fiber material having excellent adsorptive properties can be produced with a higher overall yield or residual rate than conventionally. Note that the higher the residual rate, the higher the total yield, so the higher the residual rate, the better.

EXAMPLES The present invention will be described in more detail with reference to examples below, but the technical scope of the present invention is not limited to the following examples.

<Example 1>
As a catalyst, a mixed catalyst of methanesulfonic acid (MS) and diammonium hydrogen phosphate (DAHP) was used. A mixed catalyst aqueous solution containing methanesulfonic acid and diammonium hydrogen phosphate at a weight ratio of 75:25 was prepared so that the concentration of the mixed catalyst was 5-8% (W/V).

A needle-punched non-woven fabric made of rayon fiber (3.3 dtex, 76 mm) and having a basis weight of 300 g/m ² is impregnated with the above mixed aqueous solution, squeezed out, and dried to obtain a mixed catalyst of 8 to 10% (W / W ) to obtain a pretreated nonwoven fabric.

The obtained pretreated nonwoven fabric was heated to 900° C. in 40 minutes in a nitrogen atmosphere. Subsequently, activation treatment was performed for 12 minutes in a nitrogen stream containing water vapor with a dew point of 60° C. at that temperature to prepare a sheet-like activated carbon fiber material (Example 1).

<Example 2>
An activated carbon fiber material of Example 2 was produced in the same manner as in Example 1, except that the weight ratio of the mixed catalyst in Example 1 was changed to methanesulfonic acid:diammonium hydrogen phosphate=50:50.

<Example 3>
An activated carbon fiber material of Example 3 was produced in the same manner as in Example 1, except that the weight ratio of the mixed catalyst in Example 1 was changed to methanesulfonic acid:diammonium hydrogen phosphate=25:75.

<Comparative Example 1>
Instead of the mixed catalyst in Example 1, methanesulfonic acid was used alone as a catalyst, except that an aqueous catalyst solution prepared so that the concentration of methanesulfonic acid was 5 to 8% (W / V) was used. An activated carbon fiber material of Comparative Example 1 was produced in the same manner as in Example 1.

<Comparative Example 2>
Instead of the mixed catalyst in Example 1, diammonium hydrogen phosphate was used alone as a catalyst, and an aqueous catalyst solution prepared so that the concentration of diammonium hydrogen phosphate was 5 to 8% (W / V) was used. Except for this, an activated carbon fiber material of Comparative Example 2 was produced in the same manner as in Example 1.

<Measurement and evaluation method>
The physical properties and performance of the activated carbon fiber sheet obtained as described above were measured and evaluated by the following methods. Various numerical values that define the present invention can be obtained by the following measurement methods and evaluation methods.

<Total yield (dry basis)>
The activated carbon fiber material and its precursor (non-woven fabric before being impregnated with the mixed catalyst) are dried in a dryer at 115 ± 5 ° C. for 3 hours or more, weighed, and the total yield (dry basis) is calculated according to the following formula 1. (unit: %) was calculated.
Total yield (dry basis) = weight of activated carbon fiber material / weight of precursor x 100 Equation 1

<Basis weight (weight per unit area)>
The activated carbon fiber material was allowed to stand in an environment of 23±2° C. temperature and 50±5% relative humidity for 12 hours or longer, and the grammage (unit: g/m ² ) was determined from the weight and length and width dimensions.

<Film thickness (sheet thickness)>
Let the activated carbon fiber material stand in an environment with a temperature of 23 ± 2 ° C and a relative humidity of 50 ± 5% for 12 hours or more, and use a digital small thickness gauge FS-60DS (Daiei Kagaku Seiki Seisakusho Co., Ltd.) to measure 0 The film thickness (unit: mm) was measured under a load of 3 KPa.

<Bulk density>
It was calculated by the following formula 2.
Bulk density (unit: g/cm ³ )=(grammage/10000)/(film thickness/10) Equation 2

<BET specific surface area>
<Specific surface area>
About 30 mg of the activated carbon fiber material was sampled, vacuum-dried at 200° C. for 20 hours, weighed, and measured using a high-precision gas/vapor adsorption measuring device BELSORP-maxII (Microtrac Bell). The amount of nitrogen gas adsorbed at the boiling point of liquid nitrogen (77K) was measured in the range of the relative pressure of 10 ^-8 order to 0.990 to prepare the adsorption isotherm of the sample. This adsorption isotherm is analyzed by the BET method in which the analysis relative pressure range is automatically determined under the conditions of adsorption isotherm type I (ISO9277), and the BET specific surface area per weight (unit: m ² /g) is obtained, This was defined as the specific surface area (unit: m ² /g).

<Total pore volume>
The total pore volume (unit: cm ³ /g) was calculated by the one-point method from the result of the isothermal adsorption line obtained in the section on the specific surface area at a relative pressure of 0.990.

<Average pore size>
It was calculated by the following formula 3.
Average pore diameter (unit: nm) = 4 x total pore volume x 10 ³ ÷ specific surface area Equation 3

<Methylene blue adsorption performance>
The result of measurement according to the methylene blue decolorizing power (unit: ml/g) of powdered activated carbon for water supply (JWWA K113) specified by the Japan Water Works Association was defined as the methylene blue adsorption performance (unit: ml/g).

<Iodine adsorption performance>
It was measured according to the iodine adsorption performance (unit: mg/g) of powdered activated carbon for water supply (JWWA K113) standardized by the Japan Water Works Association.

<Water content>
After leaving the activated carbon fiber material in an environment with a temperature of 23 ± 2 ° C and a relative humidity of 50 ± 5% for 12 hours or more, 0.5 to 1.0 g of a sample is collected and dried in a dryer at 115 ± 5 ° C for 3 hours. The moisture content (unit: %) was obtained from the change in weight during drying.

Table 1 shows the results of measuring the physical properties and performance of Examples 1-3 and Comparative Examples 1 and 2.

<Thermal weight residual rate>
Approximately 3 mg of the pretreated nonwoven fabric used in the production methods of Example 3 and Comparative Examples 1 and 2 was collected before carbonization and used as a test sample for thermal weight residual ratio. Using a simultaneous differential thermogravimetry device TG/DTA7200 (SII Nanotechnology Co., Ltd.), the specimen sample is held in a nitrogen atmosphere at 30 ° C. for 10 minutes, then the initial weight is measured, and then 10 ° C. to 900 ° C. /min and held for 60 minutes.

From the following equation 4, the thermogravimetric residual ratio (unit: %) of the sample at each temperature was measured to obtain the thermogravimetric residual ratio of the carbon fiber material.
Weight of test sample under each temperature condition/initial weight x 100 Formula 4

Table 2 shows the measurement results of the thermal weight residual rate. In Table 2, Test Example 3 is a test using the pretreated nonwoven fabric used in Example 3, Comparative Test Example 1 is a test using the pretreated nonwoven fabric used in Comparative Example 1, and Comparative Test Example 2 shows the test using the pretreated nonwoven fabric used in Comparative Example 2.

It is considered that the thermogravimetric residual rate of the carbon fiber material not subjected to activation treatment is approximately proportional to the total yield of the activated carbon fiber material after activation. Therefore, it is considered that the higher the thermogravimetric residual ratio of the carbon fiber material that has not undergone the activation treatment, the higher the overall yield of the activated carbon fiber material that can be produced.

Comparing Test Example 3 and Comparative Test Example 1, Test Example 3 is superior in the residual rate. Further, when comparing Test Example 3 and Comparative Test Example 2, Comparative Example 2 has a higher residual rate when the temperature is raised to 800 ° C., but when it reaches 900 ° C., Test Example 3 is higher than Comparative Test Example 2. The retention rate is higher than that of 100%, and the longer the retention time, the higher the tendency. A heating temperature in the vicinity of 900° C. is a suitable heating temperature for producing an activated carbon fiber material having excellent adsorptive properties.

Claims (5)

carbonizing and activating a cellulose-based material holding a mixed catalyst containing an organic sulfonic acid-based catalyst and a phosphoric acid-based catalyst in an inert gas atmosphere;
The weight ratio of the organic sulfonic acid-based catalyst and the phosphoric acid-based catalyst contained in the mixed catalyst is 10:90 to 90:10.
A method for producing an activated carbon fiber material. The method for producing an activated carbon fiber material according to claim 1, comprising carbonizing the cellulosic material at a temperature of 450-1300°C and activating it at a temperature of 750-1200°C. Claim 1 or 2, wherein the organic sulfonic acid catalyst is one or more selected from the group consisting of methanesulfonic acid, p-toluenesulfonic acid, naphthalenesulfonic acid, benzenesulfonic acid, and camphorsulfonic acid. 3. A method for producing an activated carbon fiber material according to . The phosphoric acid-based catalyst is one or more selected from the group consisting of phosphoric acid, ammonium dihydrogen phosphate, diammonium hydrogen phosphate, triammonium phosphate, and guanidine phosphate. 4. The method for producing an activated carbon fiber material according to any one of 3. A method for producing an activated carbon fiber material according to any preceding claim, wherein the cellulosic material comprises regenerated cellulose fibers derived from wood or cotton.