WO2003026792A1 - Activated carbon fiber and process for producing the same - Google Patents

Abstract

Activated carbon fibers excellent in both the ability to adsorptively remove trihalomethane compounds and the ability to adsorptively remove substances causative of a moldy odor. The fibers are characterized by giving at 77.4 K a nitrogen adsorption isotherm which satisfies all the following, provided that the nitrogen gas adsorption at a relative pressure of P/P0 is indicated by V(P/P0): the value of V(0.1) is 200 cc/g or higher, the value of V(0.1)/V(0.2) is 0.92 to 0.99, the value of V(0.2)/V(0.8) is 0.80 to 0.95, and the value of V(0.8)/V(1.0) is 0.80 to 0.90.

Description

 Specification

 Activated carbon fiber and method for producing the same

 Technical field

 The present invention relates to a novel activated carbon fiber and a method for producing the same.

 Background technology

 Activated carbon fibers have different characteristics from granular or powdered activated carbon in not only their appearance but also their pore structure. 'Activated carbon fibers with such characteristics are widely used for various applications including adsorbents.

 Since activated carbon fibers are fibrous as the name implies, they generally have a larger exposed surface per unit weight than granular or powdered activated carbon. For this reason, it exhibits characteristics that it is easier to make contact with the object to be processed and that the pressure loss during passage of the object fluid can be reduced.

 Especially for drinking water purification, water purifiers using activated carbon fibers as adsorbents are widely used to remove residual chlorine (so-called “smelling smell”). However, in recent years, eutrophication of river water quality has been regarded as a problem, and removal of organochlorine compounds (so-called “trihalomethanes”) in tap water and removal of “fungus odor” which is considered to be derived from microorganisms have been called “calcium”. It is required with the removal of "odor".

 Activated carbon fiber has a large specific surface area and has many micropores, so it is very effective for removing the smell of powder. On the other hand, in removing the moldy odor, since the substance causing the moldy odor is a macromolecule, it is difficult to be trapped in the micropores of the activated carbon fiber and is not suitable for the activated carbon fiber.

Improvements in the ability of activated carbon fibers to remove trihalomethanes have been described, for example, in JP-A-6-99064, JP-A-7-1455506, and JP-A-10-24442. No. 53, Japanese Unexamined Patent Application Publication No. 11-240708, Japanese Unexamined Patent Application Publication No. 1-256969, etc. have been proposed. These are all intended to extend the life of the activated carbon fiber by desorbing and regenerating the trihalomethanes adsorbed on the activated carbon fiber. Furthermore, as a technique for simultaneously removing trihalomethanes and fungal odor-causing substances, the present applicant has disclosed in Japanese Patent Application Laid-open No. Hei 11-244707 that not only micropores but also mesopores. Activated carbon fiber is proposed. However, these conventional techniques are not necessarily sufficient as materials for removing both trihalomethanes and fungi-causing substances. In particular, it has improved not only the adsorption capacity (ie, the so-called equilibrium adsorption capacity) when the treated water does not flow (that is, under static conditions), but also the removal capacity when the treated water is used, which is the actual use condition for water purification. There is a lot of room to do.

 Disclosure of the invention

 A main object of the present invention is to provide an activated carbon fiber which is excellent in both the performance of removing and adsorbing trihalomethanes and the performance of removing and adsorbing substances causing moldy odor.

 As a result of repeated studies in view of the problems of the prior art, the present inventors have found that an activated carbon fiber having a specific microstructure can achieve the above object, and have completed the present invention.

 That is, the present invention relates to the following activated carbon fiber and a method for producing the same.

 1. Relative pressure P / P on nitrogen adsorption isotherm at 77.4 K. V (P / Po)

 (a) V (0.1) is greater than 200 c c / g,

 (b) The value of V (0.1) / V (0.2) is 0.92 to 0.99,

 (c) V (0.2) / V (0.8) is 0.80 to 0.95 and

 (d) V (0.8) ZV (1.0) is 0.80 to 0.90

Activated carbon fiber characterized by satisfying all requirements.

 2. A water purification material containing the activated carbon fiber according to the above item 1.

 3. A method for producing activated carbon fibers for adsorption of trihalomethanes and moldy odor-causing substances, comprising: (1) 0.01 to 5% by weight of at least one metal component of vanadium, platinum and iron as an activated carbon precursor. A step of melt-spinning the precursor, passivating and activating the precursor using the contained pitch to obtain an activated carbon fiber, and

 (2) By measuring the nitrogen gas adsorption amount of the obtained activated carbon fiber, the relative pressure PZP in the nitrogen adsorption isotherm at 77.4 K was obtained. V (P / Po)

(a) V (0.1) is 200 cc / g or more, (b) The value of V (0.1) / Ϋ (0.2) is 0.92 to 0.99,

 (c) V (0.2) ZV (0.8) is 0.80 to 0.95 and

 (d) The value of V (0.8) / Y (1.0) is 0.80 to 0.90

A process for selecting activated carbon fibers that satisfy all of the requirements.

 4. A method for adsorbing and removing trioctanemethane and fungi-causing substances using activated carbon fiber,

 The activated carbon fiber has a relative pressure PZP in the nitrogen adsorption isotherm at 77.4 K. V (P / Po)

 (a) The value of V (0.1) is 200 c cZg or more,,

 (b) The value of V (0.1) / V (0.2) is 0.92 to 0.99,

 (c) V (0.2) ZV (0.8) is 0.80 to 0.95 and

 (d) The value of V (0.8) / V (1.0) is 0.80 to 0.90

A method characterized by satisfying all of

 5. A method for removing trioctanemethane and fungi-causing substances by passing water to be treated through a tubular body filled with activated carbon fibers according to the above item 1.

 Hereinafter, the present invention will be described in detail. In the present invention, “micropore” refers to a pore having a pore diameter of less than 20 A, “mesopore” refers to a pore having a pore diameter of 20 to 500 A, and “macropore” refers to a fine pore. A pore having a pore diameter of more than 50 OA.

 1. Activated carbon fiber

 The activated carbon fiber of the present invention has a nitrogen adsorption isotherm at 77.4 K at a relative pressure PZP. V (P / Po)

 (1) When the value of V (0.1) (hereinafter referred to as “a value”) is 200 c cZg or more,

 (2) The value of V (0.1) ZV (0.2) (hereinafter referred to as “b value”) is 0.92 to 0.99,

 (3) The value of V (0.2) ZV (0.8) (hereinafter referred to as “c value”) is 0.80 to 0.95 and

 (4) The value of V (0.8) ZV (1.0) (hereinafter referred to as “d value”) is 0.80 to 0.90

Is satisfied. In the present invention, the nitrogen adsorption isotherm is created as follows. Cool the activated carbon fiber to 77.4 K (boiling point of nitrogen), introduce nitrogen gas, and measure the adsorption amount of nitrogen gas V [cc / g] by the volumetric method. At this time, the pressure P [mmHg] of the nitrogen gas to be introduced is gradually increased to the saturated vapor pressure P of the nitrogen gas. The value divided by [mmHg] is the relative pressure PZP. The nitrogen adsorption isotherm is created by plotting the amount of adsorption with respect to each relative pressure. In this nitrogen adsorption isotherm, let the amount of nitrogen gas adsorbed at each relative pressure (PZPo) be V (P / Po). For example, the nitrogen gas adsorption amount when the relative pressure is 0.1 is expressed as V (0.1). As shown in Fig. 1, the nitrogen adsorption isotherm can be obtained by taking the relative pressure (P / P.) On the horizontal axis and the nitrogen gas adsorption amount V (P / Po) on the vertical axis. In measuring the nitrogen gas adsorption amount, a commercially available automatic gas adsorption amount measuring device can be used. For example, trade name “AUTOSORB-6” (manufactured by QUANT CHROME) or the like can be preferably used.

 The value a is set to 200 cc / g or more, preferably 220 cc / g or more. If the a value is less than 200 ccZg, it may generally be difficult to effectively adsorb and remove the substance to be adsorbed.

 The b value is 0.92 to 0.99, preferably 0.95 to 0.99. If the b value is less than 0.92, the number of micropores and mesopores having a pore diameter close to the pore diameter of the micropores becomes excessive, so that the desired adsorption performance may not be obtained. is there. On the other hand, if the b value exceeds 0.99, the number of micropores and mesopores having a pore diameter close to that of the micropores becomes too small, so that the adsorption performance may be reduced.

 The c value is set to 0.80 to 95, preferably 0.85 to 0.95. If the c value is less than 0.80, the mesopores having a pore diameter of about 20 to 100 A are excessive, and the effect of the present invention may not be obtained. If the c value exceeds 0.95, the number of mesopores in the vicinity of the pore diameter of 20 to 100 A becomes too small, so that the effect as the water purification material of the present invention may not be obtained.

The d value is 0.80 to 0.90, preferably 0.82 to 0.90. If the d value is less than 0.80, the macropores and the mesopores having a pore diameter close to the macropore diameter become excessive, so that the desired adsorption performance may not be obtained. You. If the d-value exceeds 0, 90, the macropores and the mesopores having a pore diameter close to the macropore diameter become too small, so that the performance as the material for water purification and purification etc. of the present invention is reduced. The power may not be exerted.

 The activated carbon fiber of the present invention can be suitably used for conventional activated carbon fiber applications. In particular, it can be suitably used as a material for adsorbing and removing trihalomethanes and fungi-causing substances. Therefore, it can be used as a material for water purification and gas purification. For example, when used as a water purification material, the material of the present invention may be used as it is instead of a known adsorbent in a water purifier or the like. The present invention also includes a method for removing trihalomethanes and moldy odor-causing substances using the activated carbon fibers. Specifically, by passing water to be treated through the tubular body filled with the activated carbon fiber of the present invention, trihalomethines and fungal odor-causing substances in the water to be treated can be adsorbed and removed. At this time, the amount of water passed, the amount of the material of the present invention, and the like may be in accordance with known methods and conditions.

 2. Manufacturing method of activated carbon fiber

 The activated carbon fiber of the present invention may be produced by any method as long as it has the above-mentioned a to d values. For example, the following production method is preferable.

 That is, in a method for producing an activated carbon fiber by melt-spinning, infusibilizing, and activating the activated carbon precursor, at least one metal component of vanadium, platinum, and iron is used as the activated carbon precursor. According to the method characterized by using a pitch containing 1 to 5% by weight, the activated carbon fiber of the present invention can be obtained more reliably.

 The metal component is at least one of vanadium, platinum and iron. When two or more metal components are used in combination, the type of metal to be combined, the ratio thereof, and the like may be appropriately set according to the use of the activated carbon fiber, the purpose of use, and the like.

The content of the metal component is adjusted so as to be 0.01 to 5% by weight, preferably 0.1 to 2% by weight in the activated carbon precursor. If the content of the metal component is less than 0.01% by weight, activated carbon fibers having the above a-values-d cannot be obtained due to weakening of the action of the metal during the activation reaction. There is. Conversely, if it exceeds 5% by weight, Since the metal component condenses and forms in the charcoal, the physical strength of the activated carbon fiber is remarkably reduced, which may make it impractical as a water purification material. The content of the metal component is not a content as a metal compound but a content in terms of a metal element, and is a value measured by an ICP emission spectrometry.

 The activated carbon precursor can be prepared, for example, by mixing a compound containing the metal component (metal compound) and pitch.

 The pitch is not particularly limited as long as it can be activated carbon by infusibilization, carbonization, and the like, and can be mixed with a metal compound. For example, any of petroleum pitch, coal pitch, synthetic pitch and the like can be used. The optical properties may be either isotropic or anisotropic.

 In the case of preparing an activated carbon precursor, for example, an activated carbon precursor containing pitch and a metal component may be obtained by mixing and stirring a coal tar, which is a raw material for pitch, and a metal compound in a solvent, and then performing distillation under reduced pressure. it can.

 The metal compound is not particularly limited as long as these metal components are contained, and any of an inorganic compound and an organic compound can be used. As the inorganic compound, for example, inorganic salts such as chloride, nitrate, and acetate are used. Specifically, iron chloride, iron nitrate, iron acetate and the like can be exemplified. As the organic compound, an organic metal complex of the above metal component and acetylacetone / cyclopentene is used. Specifically, iron trisacetyl acetatonate, iron acetyl acetatonate, trissix pen penis genil iron and the like can be exemplified.

The method of mixing the metal compound and the pitch is not limited as long as they can be uniformly mixed. For example, the metal compound and the pitch may be mixed as they are, or both may be mixed in an appropriate solvent. In particular, it is preferable to mix the metal compound and the pitch in a solvent. The solvent is not particularly limited as long as it can dissolve both the metal compound and the pitch.Pitch to be used is selected from known solvents such as quinoline, benzene, dichloromethane, toluene, xylene, tetrahydrofuran, methanol, and ethanol. And the type of the metal compound may be appropriately selected. For example, when an acetylacetone complex is used as the iron compound and a coal-based isotropic pitch is used as the pitch, quinoline or the like can be used. The amount of the solvent used is not particularly limited as long as a uniform activated carbon precursor can be obtained, and may be appropriately set according to the type of the solvent, the metal compound, and the like to be used.

 Next, after spinning the obtained activated carbon precursor, it is subjected to infusibilization treatment and / or carbonization treatment and then to activation treatment, whereby the activated carbon fiber of the present invention can be obtained. The spinning method, the infusibilization treatment, the carbonization treatment and the activation treatment are preferably carried out by the following methods.

 The spinning method can be performed according to a known melt spinning method. The melting temperature and the spinning temperature are generally set to a temperature equal to or higher than the softening point of the activated carbon precursor, and preferably set to a temperature higher by 30 to 100 ° C. than the softening point. The molten activated carbon precursor is sent to the nozzle of a spinning machine, and is discharged from a nozzle surface having many pores while forming fibers in an atmosphere controlled at a spinning temperature or lower.

 In the infusibilization treatment, the activated carbon precursor is heated from a temperature below its melting point to about 400 ° C at a rate of 0.1 to 10 ° CZ in an inert gas atmosphere or an oxygen-containing gas atmosphere. Can be implemented.

 In the carbonization treatment, the activated carbon precursor is heated to about 800 to 1200 ° C. at a temperature increasing rate of 5 to 10 ° C.Z under an inert gas atmosphere such as nitrogen gas and argon gas. It can be implemented by maintaining the maximum temperature at that time for a maximum of about 10 minutes. The activation treatment is an activated carbon precursor that has been subjected to infusibilizing treatment and Z or carbonization treatment in a gas atmosphere in which water vapor, carbon dioxide, oxygen, a mixed gas thereof, and these gases are diluted with an inert gas such as nitrogen. Is held at a temperature of about 800 to 1200 ° C. for about 5 to 120 minutes.

 In this case, the activated carbon precursor to be subjected to the carbonization treatment or the activation treatment preferably contains 5% by weight or more of oxygen atoms. When the oxygen atoms are contained in an amount of 5% by weight or more, when the oxygen atoms are desorbed in the carbonization or activation reaction, the metal components interact with each other. The effect of appropriately perforating mesopores having a pore diameter close to the pore diameter of the pores is obtained. The content of oxygen atoms can be appropriately adjusted under infusibilizing conditions such as infusibilizing temperature and infusibilizing time.

In the present invention, in order to more reliably obtain an activated carbon fiber particularly suitable for adsorbing trihalomenes and a substance causing a moldy odor, the nitrogen gas of the activated carbon fiber thus obtained is used. In the nitrogen adsorption isotherm at 77.4 K, the nitrogen gas adsorption amount at relative pressure P / P _Q is defined as V (P / Po)

 (a) V (0.1) is greater than 200 c c / g,

 (b) The value of V (0.1) / V (0.2) is 0.92 to 0.99,

 (c) V (0.2) / V (0.8) is 0.80 to 0.95 and

 (d) The value of V (0.8) / V (1.0) is 0.80 to 0.90

It is desirable to have a step of selecting an activated carbon fiber that satisfies all conditions. The method for measuring the nitrogen gas adsorption amount may be the same as described above.

 The present invention also includes a method for selecting activated carbon fibers for adsorbing trihalomethanes and fungi-causing substances. That is, a method for selecting activated carbon fibers for adsorbing trioctanes and moldy odor causing substances,

 By measuring the amount of nitrogen gas adsorbed on the activated carbon fiber, the relative pressure PZP was obtained in the nitrogen adsorption isotherm at 77.4K. Let the amount of nitrogen gas adsorbed at V be P (P / Po)

 (a) V (0.1) is greater than 200 c c / g,

 (b) The value of V (0.1) / V (0.2) is 0.92 to 0.99,

 (c) V (0.2) / V (0.8) is 0.80 to 0.95 and

 (d) The value of V (0.8) / V (1.0) is 0.80 to 0.90

The present invention encompasses a method characterized by selecting an activated carbon fiber that satisfies all conditions. This selection method can be applied to all activated carbon fibers, including activated carbon fibers produced by a method other than the above-mentioned production method. The method for measuring the nitrogen gas adsorption amount may be the same as described above. Activated carbon fibers satisfying all of the above conditions (a) and (b) exhibit an excellent effect as a material for adsorbing trihalomenes and fungal odor-causing substances. The size of the molecules of trihalomethanes is not so large that they cannot penetrate into the pores of Miku like the substances that cause moldy odor. Therefore, we focused on activated carbon fibers that have both micropores and mesopores, and as a result of a detailed study, found that the small pores where the mesopores were close to the micropores and the large pores where the mesopores were close to the Mactopores. By controlling the fine structure with a hot spring such as nitrogen adsorption (nitrogen gas adsorption amount) so that it is occupied in a specific range, the adsorption performance of mold odor-causing substances can be maintained while maintaining high trioctane methane adsorption performance. Can also be improved.

 Therefore, the activated carbon fiber of the present invention exerts an excellent effect as an adsorbent capable of removing virtually all of low molecular substances represented by a odor of lime, macromolecules such as trichloromethanes, and substances causing a moldy odor. be able to. That is, the activated carbon fiber of the present invention having such characteristics is useful as an activated carbon fiber for adsorbing trioctane compounds and fungi-causing substances, and specifically, a water purification material and a gas purification material. Etc. can be suitably used.

 BRIEF DESCRIPTION OF THE FIGURES

 Figure 1 shows the nitrogen adsorption isotherms of the iron-containing activated carbon fiber of Example 1, the platinum-containing activated carbon fiber of Example 2, the metal-free activated carbon fiber of Comparative Example 1, and the iron-containing activated carbon fiber of Comparative Example 3. It is a figure showing a line.

 BEST MODE FOR CARRYING OUT THE INVENTION

 Hereinafter, Examples and Comparative Examples will be shown, and the features of the present invention will be shown more clearly. However, the present invention is not limited to these examples.

 In this example, the amount of nitrogen gas adsorbed on the activated carbon fiber was measured using "AUTOSORB-6" (trade name, manufactured by QUANTCHROME).

 Example 1

'100 g of coal tar from which water and quinoline-insoluble matter were removed was heated to 90 ° C under a nitrogen atmosphere, and 20 O ml of a quinoline mixed solution in which 6 g of acetylacetonatoiron was dissolved was added thereto. The mixture was gradually added dropwise and stirred for 90 minutes. Next, this was distilled under reduced pressure, and further reacted at 330 ° C. for 3 hours while blowing air at a rate of 3 LZ to obtain an iron-containing copper rubicite. The iron content of this pitch was 0.23% by weight. The obtained iron-containing coal tar pitch was melt-extruded and spun at a melting temperature of 320 ° C to obtain pitch fibers. The spun pitch fibers are heated in the air from room temperature at a heating rate of 1 to 10 and held at the maximum temperature of 364 ° C for 4 minutes, and the infusibilizing treatment is performed over a total infusibilizing time of 65 minutes. Was done. Next, the infusibilized pitch fiber was exposed to saturated steam at 850 ° C. for 60 minutes in a nitrogen atmosphere to perform an activation treatment to obtain an iron-containing activated carbon fiber. Table 1 shows a to d values of the obtained activated carbon fibers. Figure 1 shows the nitrogen adsorption isotherm. Example 2

 A coal tar pitch was obtained in the same manner as in Example 1, except that 5.7 g of acetyl acetonato platinum was used instead of 6 g of acetyl acetonato iron. The platinum content of this pitch was 2.60% by weight. The spun pitch fibers were heated from room temperature in the air at a rate of temperature increase of 2 ° C / min, and kept at 375 for 15 minutes for infusibility treatment. Next, the infusibilized pitch fiber was exposed to saturated steam at 850 for 35 minutes in a nitrogen atmosphere to perform an activation treatment to produce a platinum-containing activated carbon fiber. Table 1 shows a to d values of the obtained activated carbon fibers. Figure 1 shows the nitrogen adsorption isotherm.

 Comparative Example 1

 Activated carbon fibers were produced in the same manner as in Example 1, except that no metal compound was mixed and the activation treatment time was 30 minutes. Table 1 shows a to d values of the obtained activated carbon fibers. Figure 1 shows the nitrogen adsorption isotherm.

 Comparative Example 2

 Production of iron-containing activated carbon fiber was attempted in the same manner as in Example 1, except that the amount of acetyl acetonato iron was changed to 180 g. At this time, the iron content of the pitch was 7% by weight. However, yarn breakage occurred frequently during spinning, and there was a problem in operation. The produced iron-containing activated carbon fiber easily collapsed into a powder form and powdered. In addition, there were many that were recognized as aggregates of iron compounds. Activated carbon fibers were remarkably powdered, and it was difficult to measure ad values.

 Comparative Example 3

Activated iron-containing carbon fibers were produced in the same manner as in Example 1 except that the maximum temperature in the infusibilization treatment was changed to 26.4 t :. At this time, the oxygen atom content in the activated carbon precursor was 2.55%. Table 1 shows a to d values of the obtained activated carbon fibers. Figure 1 shows the nitrogen adsorption isotherm. Tatami mat

V (0.1) V (0.1) / V (0.2) V (0.2) / V (0.8) V (0.8) / V (1.0) Example 1 342 0.95 0.92 0.85

 Example 2 246 0.96 0.82 0.88

 Comparative Example 1 328 0.97 0.97 0.99

 Comparative Example 2 Impossible Impossible Impossible Impossible Impossible

 Comparative Example 3 156 0.94 0.89 0.98 Test Example 1

 For the activated carbon fibers obtained in each of the examples and comparative examples, a total trihalomethane filtration ability test and a mold odor filtration ability test were performed. The results are shown in Table 2. Each test method was performed by the following method.

 (1) Total trihalomethane filtration capacity test

8.4 g of a milled sample based on JI SS-3201 “Test method for household water purifiers (continuous method)” was filled into an acrylic container so as to be 48 mm (diameter) · 30 mm (height). trihalomethane _{TTHM (CHC 13: CHC 1 2} B r: C HC 1 B r 2: CHB r 3 = 45: 30: 20: 5) passing water concentration raw water 102. 4 ppt at a flow rate 3 LZ worth of did. Outlet concentration C and initial concentration C at this time. The ratio of C / C. Is 0.2, which is defined as the filtration capacity. The above analyzer was run under the headspace method using the trade name “GC-I 14B” (manufactured by Shimadzu Corporation).

 (2) Mold smell filtration capacity test

JI SS-320 1 Acrylic container was filled with 8.4 g of a milled sample based on the “Test method for household water purifiers (continuous method)” so as to be 48 mm (diameter) · 30 mm (height). Then, raw water having a 2-methylisoborneol concentration of 5.5 ppt was passed at a flow rate of 3 L / min. Outlet concentration C and initial concentration C at this time. The flow rate at which the ratio CZCQ became 0.2 was defined as the filtration capacity. The above analyzer was performed by the purge trap method using the trade name “GCMS-QP 5050” (manufactured by Shimadzu Corporation). Table 2

これらの結果からも明らかなように、 本発明の活性炭素繊維は、 トリ八口メタ ン類の吸着除去性能はもとより、 黴臭原因物質の吸着除去性能においても優れた 効果を発揮できることがわかる。 なお、 比較例 2は、 粉ィ匕が著しいため、 ろ過能 力試験の実施は困難であった。

As is clear from these results, the activated carbon fiber of the present invention can exert excellent effects not only on the adsorption and removal performance of trioctane methanes but also on the adsorption and removal performance of the fungi-causing substance. In Comparative Example 2, it was difficult to carry out a filtration ability test due to the remarkable powdering.

Claims

The scope of the claims  1. 77. Relative pressure P / P on nitrogen adsorption isotherm at 4K. V (PXPo)  (a) The value of V (0.1) is 200 c cZg or more,  (b) V (0.1) ZV (0.2) is 0.92 to 0.99,  (c) V (0.2) ZV (0.8) is 0.80 to 0.95 and  (d) The value of V (0.8) / V (1.0) is 0.80 to 0.90 Activated carbon fiber characterized by satisfying all requirements.  2. A water purification material containing the activated carbon fiber according to claim 1. 3. A method for producing activated carbon fibers for the adsorption of trihalomenes and fungi-causing substances,  (1) Using a pitch containing 0.01 to 5% by weight of at least one metal component of vanadium, platinum and iron as an activated carbon precursor, melt-spinning this precursor, infusibilizing it, and activating it Obtaining activated carbon fibers by  (2) By measuring the amount of nitrogen gas adsorbed on the obtained activated carbon fiber, the relative pressure PZP in the nitrogen adsorption isotherm at 77.4 K was measured. Nitrogen adsorption at (P / Po)  (a) The value of V (0.1) is 200 c cZg or more,  (b) The value of V (0.1) / V (0.2) is 0.92 to 0.99,  (c) The value of V (0.2) / V (0.8) is 0.80 to 0.95 and  (d) The value of V (0.8) / Y (1.0) is 0.80 to 0.90 A process for selecting activated carbon fibers that satisfy all of the requirements. 4. A method of adsorbing and removing trioctanes and moldy odor causing substances using activated carbon fiber,  In the nitrogen adsorption isotherm at 77.4 K, the activated carbon fiber has a nitrogen gas adsorption amount at a relative pressure Ρ / Ρο as V (P / Po).  (a) The value of V (0.1) is 200 c cZg or more,  (b) The value of V (0.1) / Y (0.2) is 0.92 to 0.99, (c) V (0.2) ZV (0.8) is 0.80 to 0.95 and (d) A method characterized in that the value of V (0.8) / V (1.0) satisfies all of 0.80 to 0.90.