JP2001170450A - Photocatalytic activated carbon sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a photocatalytic activated carbon sheet using activated carbon fiber which is easily produced and obtained on an industrial scale, and which is used for removing odorous substances, harmful substances, mold, etc. in living spaces and working spaces. Provided is a photocatalytic activated carbon sheet having a sufficient initial removal performance and capable of maintaining the removal performance for a long period of time. SOLUTION: It is made of titania fiber, activated carbon fiber, and at least one fiber selected from the group consisting of plant fiber, synthetic resin fiber, inorganic fiber and metal fiber, and the titania fiber has a basis weight of about 1 g / m ^2. ~ photocatalyst activated carbon sheet is approximately 500 g / m ^2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a photocatalytic activated carbon sheet. Specifically, the present invention relates to a photocatalytic activated carbon sheet suitably used for removing malodorous substances, harmful substances, mold, and the like in a living space or a working space.

[0002]

2. Description of the Related Art In recent years, various studies have been made on deodorizers composed of activated carbon fibers and photocatalysts for the purpose of removing malodorous substances. 11-4761
No. 1) has been proposed.

[0003]

However, when the photocatalyst fine particles are carried on activated carbon fibers, the deodorizing effect of the activated carbon fibers can be maintained to some extent by the action of the photocatalyst fine particles, but the activated carbon fibers inherently exhibit the inherent adsorption performance. There was something I could not do. Further, there is a problem of fixing strength of the photocatalyst fine particles to the activated carbon fiber. On the other hand, a photocatalytic activated carbon in which a photocatalyst is supported at the stage of producing activated carbon has been proposed, but it has been necessary to produce it using a specific raw material such as a Ti-containing activated carbon precursor organic material.

An object of the present invention is to provide a photocatalytic activated carbon sheet using activated carbon fiber which is easily produced and obtained on an industrial scale, and which is used for removing odorous substances, harmful substances, mold and the like in living spaces and working spaces. An object of the present invention is to provide a photocatalytic activated carbon sheet having a sufficient initial removal performance and capable of maintaining the removal performance for a long period of time.

[0005]

Means for Solving the Problems As a result of intensive studies conducted by the present inventor to solve the above problems, a titania fiber having a photocatalytic function by itself as a photocatalyst in a photocatalytic activated carbon sheet comprising an activated carbon fiber and a photocatalyst. In the case of using a photocatalyst activated carbon sheet, it has been found that it is possible to provide a photocatalytic activated carbon sheet having sufficient initial removal performance and maintaining the removal performance for a long time without impairing the original adsorption performance of the activated carbon fiber, and completed the present invention. I came to.

That is, the present invention provides (1) a photocatalytic activated carbon sheet comprising titania fibers and activated carbon fibers,

(2) a photocatalytic activated carbon sheet comprising titania fibers, activated carbon fibers, and at least one fiber selected from the group consisting of plant fibers, synthetic resin fibers, inorganic fibers, and metal fibers;

(3) The basis weight of the titania fiber is about 1 g /
a photocatalyst activated carbon sheet of the (1) or (2) wherein characterized in that the m ² ~ about 500 g / m ^2.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The photocatalytic activated carbon sheet of the present invention comprises a titania fiber and an activated carbon fiber. For example, a sheet having a two-layer structure in which a sheet composed of an activated carbon fiber is bonded to one surface of a sheet composed of an activated carbon fiber. And a sheet having a three-layer structure in which sheets made of titania fibers are bonded to both sides of a sheet made of activated carbon fibers, and a sheet having a single layer structure made of a mixed fiber of titania fibers and activated carbon fibers. Further, at least two of these various sheets may be bonded together, or at least one of the various sheets and a sheet made of activated carbon fiber and / or a sheet made of titania fiber may be used. May be bonded together. By using titania fibers as the photocatalyst, a photocatalytic activated carbon sheet having sufficient initial removal performance and maintaining the removal performance for a long period of time can be obtained without impairing the original adsorption performance of the activated carbon fibers.

[0010] activated carbon fiber used in the present invention are produced on an industrial scale, usually apply those available, for example, specific surface area of about 500 meters ² / g or more, preferably about 1000 m ²
/ G to about 2000 m ² / g with an average diameter of about 10μ
m to about 30 μm. When the specific surface area is less than about 500 m ² / g, a photocatalytic activated carbon sheet having sufficient initial removal performance may not be obtained. Commercial products include, for example, kainol activated carbon fiber manufactured by Nihon Kainol Co., Ltd., and Taiko fibrous activated carbon manufactured by Nimura Chemical Industry Co., Ltd.

The basis weight of the activated carbon fiber varies depending on the concentration and type of the substance to be removed, the magnitude of the change with time of the concentration and the like, and is not unique, but is usually about 1 g / m ² to about 500 g.
/ M ² , preferably from about 10 g / m ² to about 100 g / m ² . If the basis weight is less than about 1 g / m ² , the resulting photocatalytic activated carbon sheet tends to have a lower initial removal performance. When the basis weight is more than about 500 g / m ² , the resulting photocatalytic activated carbon sheet has reduced air permeability, liquid permeability and the like.

The titania fiber used in the present invention can impart sufficient initial removal performance to the photocatalytic activated carbon sheet without impairing the original adsorption performance of the activated carbon fiber, and the photocatalytic activated carbon fiber has a sufficient photocatalytic action of the titania fiber. From the viewpoint that the sheet can be provided with a removal performance that can be maintained for a long period of time, its crystal structure is preferably anatase,
The ET specific surface area is, for example, about 10 m ² / g or more, preferably about 30 m ² / g or more, and the average fiber diameter is, for example, about 3 μm to about 100 μm, preferably about 5 μm to about 50 μm.
μm, more preferably about 8 μm to about 20 μm,
The fiber length is, for example, about 50 μm or more, preferably about 1 μm.
It is not less than 00 μm. When the fiber length is less than about 50 μm, when the photocatalytic activated carbon sheet is used for a long period of time, the photocatalytic activated carbon sheet may lose its constituent fibers, titania fibers, and may not be able to maintain the removal performance.

The method for producing the titania fiber is as follows.
For example, a method in which a liquid containing polymethanoxane (polytitanoxane) is spun and baked (for example, JP-A-49-12)
No. 4336, JP-A-60-215815, JP-A-9-276705) and a sol-gel method (for example, JP-A-62-223323), and preferably polymethanoxane (polytitanoxane).
And a method of spinning a liquid containing a silicon compound such as ethyl silicate and firing.

The basis weight of the titania fibers varies depending on the concentration and type of the substance to be removed, the intensity of the excitation light, and the like, and is not unique, but is usually about 1 g / m ² to about 500 g / m ² ,
Preferably from about 10 g / m ² ~ about 500 g / m ^2. When the basis weight is less than about 1 g / m ^{2, the} excitation light applied to the photocatalytic activated carbon sheet tends to be unavailable, and when the basis weight is more than 500 g / m ² , the excitation light applied to the photocatalytic activated carbon sheet is Since the number of titania fibers which are blocked by other titania fibers and to which the excitation light does not reach tends to increase, it may be difficult to obtain a photocatalytic activated carbon sheet capable of maintaining the removal performance for a long period of time.

Further, the photocatalytic activated carbon sheet of the present invention includes:
If necessary, the fibers may include at least one fiber selected from the group consisting of plant fibers, synthetic resin fibers, inorganic fibers, and metal fibers (hereinafter, simply referred to as fibers). When a titania fiber having a smooth surface and a fiber length of 50 μm or more, preferably 100 μm or more and the fiber are used, a photocatalytic activated carbon sheet having sufficient flexibility can be obtained. The surface of the titania fiber being smooth is, for example, a glass fiber that has substantially no protrusions as seen in a fiber obtained by supporting titania particles on a glass fiber. As a specific example, the number of protrusions (the height of the protrusions is equal to the average fiber diameter) in the fiber portion of the titania fiber (the length of the fiber portion is about 10 times the average fiber diameter). Less than one, and preferably the number of protrusions present in the fiber site (the height of the protrusions is at least about 10% of the average fiber diameter). )) Is less than one. In addition, the number of convex parts is shown by the average number of the convex parts of five fibers, and the average fiber diameter was obtained by measuring the place without the convex parts. When the number of the convex portions existing in the fiber portion of the titania fiber exceeds 1, a photocatalytic activated carbon sheet having sufficient flexibility may not be obtained.

Specific examples of plant fibers include wood fibers (kraft pulp, chemical pulp, mechanical pulp, etc. obtained from softwood and hardwood), non-wood fibers of plant type, recycled fibers (rayon, etc.), processed fibers of natural products ( Examples of the synthetic resin fibers include thermoplastic resin fibers (olefin resin fibers, polyester resin fibers, vinyl acetate copolymer resin fibers, polyamide resin fibers such as nylon, and acrylic resin fibers). , Polyvinyl alcohol resin fibers, diene resin fibers, polyurethane resin fibers, etc.), thermosetting resin fibers (phenol resin fibers, furan resin fibers, urea resin fibers, melamine resin fibers, aniline resin fibers, unsaturated polyester resin fibers) ,
Alkyd resin fiber, epoxy resin fiber, etc.)
Specific examples of the inorganic fibers include silicone fibers, fluorine fibers, etc., various glass fibers, alumina fibers, and the like.
Specific examples of the metal fiber include stainless steel wool. The basis weight of the fibers is, for example, about 0.1 to about 50, preferably about 0.1 to about 5 as a volume ratio to titania fibers or activated carbon fibers.

Examples of the method for producing the photocatalytic activated carbon sheet of the present invention include a method of dispersing titania fiber and activated carbon fiber in water and papermaking, a sheet obtained by dispersing titania fiber in water and papermaking, and an activated carbon fiber A method in which a sheet obtained by dispersing in water and making a paper is bonded, a resin bonding method in which titania fibers and activated carbon fibers are resin-bonded,
Needle punch method in which titania fiber and activated carbon fiber are crossed with a needle, stitch bond method in which titania fiber and activated carbon fiber are knitted with yarn, thermal bond method in which titania fiber and activated carbon fiber are thermally bonded using resin fiber And a water entanglement method in which high-pressure water is sprayed onto the titania fiber and the activated carbon fiber to entangle the fibers.

In the production of the photocatalytic activated carbon sheet, fibers such as plant fibers, synthetic resin fibers, inorganic fibers and metal fibers may be used as necessary. For example, titania fibers, activated carbon fibers and fibers A sheet obtained by dispersing titania fibers and fibers in water and bonding the sheet obtained by dispersing the activated carbon fibers and fibers in water to a sheet obtained by dispersing titania fibers and fibers in water. Method, a titania fiber, an activated carbon fiber, and a resin bond method for bonding the fiber to a resin. When the photocatalytic activated carbon sheet is used in water, the production method includes a resin bond method in which the titania fiber and the activated carbon fiber are resin-bonded, a thermal bond method in which the titania fiber and the activated carbon fiber are thermally bonded using the resin fiber, and the like. Recommended.

In a method of laminating a sheet made of titania fibers obtained by dispersing titania fibers in water and making paper and a sheet consisting of activated carbon fibers obtained by dispersing activated carbon fibers in water and making paper, etc. For example, a resin bond method, a needle punch method, a stitch bond method, a thermal bond method, a hydroentanglement method, or the like may be used. Alternatively, a method may be employed in which a sheet made of titania fibers and a sheet made of activated carbon fibers are overlapped and fixed using a fixing bracket or the like.

In using the photocatalytic activated carbon sheet of the present invention, for example, a liquid to be treated or a gas to be treated containing a substance to be removed is brought into contact with the photocatalytic activated carbon sheet, and the light is irradiated to the photocatalytic activated carbon sheet using a light source. . As the light source, for example, a sun ray, a black light, a high-pressure mercury lamp, or the like can be applied.

Examples of applications of the photocatalytic activated carbon sheet of the present invention include cleaning of contaminated rivers and lakes, decolorization of dyeing wastewater, treatment of tap water and wastewater, and gas treatment such as air. Examples include filter materials for purifiers, shoji paper, fusuma paper, wallpaper, curtains, ventilation fan covers, and the like.

[0022]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. The surface smoothness of the titania fiber was measured by the following method. Surface smoothness of titania fibers: The titania fibers were photographed with a scanning electron microscope, and the surfaces of five randomly selected fibers were examined. For each titania fiber, a fiber site (the length of the fiber site is 10 times the average fiber diameter) is randomly selected, and the height present in the fiber site is at least 30% of the average fiber diameter. The number of convex portions and the number of convex portions whose height is 10% or more of the average fiber diameter were measured, and the average number of five fibers was determined.

Example 1 1 mol of titanium tetraisopropoxide was dissolved in tetrahydrofuran and partially hydrolyzed with 1.5 mol of water.
Polytitanoxane was obtained. After adding ethyl silicate which is a partial hydrolyzate of tetraethoxysilane to this,
The solution was concentrated to prepare a spinning solution. The obtained spinning solution is applied to a pore size of 50
It was extruded from a μm spinneret and wound up at a speed of 70 m / min to obtain a continuous precursor fiber. The obtained continuous precursor fiber was left in an atmosphere at a temperature of 85 ° C. and a relative humidity of 95% for 15 hours, and then calcined at 900 ° C. to obtain a titania continuous fiber. The obtained titania continuous fiber was cut to have a length of 5 mm, an average fiber diameter of 17 μm, and a silica content of 1 μm.
A titania fiber having an anatase crystal form of 5% by weight (an electron micrograph is shown in FIG. 1) was obtained. As a result of measuring the smoothness of the surface of the obtained titania fiber, the number of protrusions having 30% or more of the average fiber diameter was 0, and 10%
The number of the above convex portions was 0.

20 parts by weight of the above titania fiber and activated carbon fiber (ACF-1603-2, manufactured by Nippon Kainol Co., Ltd.)
0) 20 parts by weight of an acrylic fiber pulp (obtained by refining acrylic fiber R-56F manufactured by Toyobo Co., Ltd. using a single refiner: freeness 310), polyester fiber (trade name: Tepilus TJ04CN, fineness) 1.5 d, length 5 mm, 10 parts by weight (manufactured by Teijin Limited) were dispersed in water, and a sheet was prepared using a square paper machine. After dehydrating the sheet, the sheet was hot-pressed at 110 ° C. to obtain a photocatalytic activated carbon sheet A (titania fiber and activated carbon fiber have a basis weight of 20 g / m ² , respectively).

A 6 W black light as an excitation light source was placed in a 5 L Pyrex glass separable reaction vessel (capacity: 6.3 L), and a photocatalytic activated carbon sheet A cut into 10 cm × 10 cm was cut from the black light by 1 c.
It was arranged in a column at a distance of m. A fan was arranged for stirring the air in the reaction vessel. The photocatalytic activated carbon sheet A had sufficient flexibility and could be arranged in a columnar shape.

A predetermined amount of acetaldehyde was introduced into the reaction vessel in a short time so that the initial concentration of acetaldehyde in the reaction vessel was 320 ppm. Fifteen minutes after the completion of the introduction, the black light was turned on and the photocatalytic activated carbon sheet A was irradiated with light for 35 minutes. The change in the concentration of acetaldehyde in the reaction vessel was measured by gas chromatography. Subsequently, the same operation was repeated a total of three times. Figure 2 shows the results.
Shown in

From the results shown in FIG. 2, one minute after the completion of the introduction, the concentration of acetaldehyde in the reaction vessel became 250 ppm. After turning on the black light and irradiating the photocatalytic activated carbon sheet A with light for 15 minutes, the concentration of acetaldehyde in the reaction vessel became 1 ppm or less. As a result of the repeated test,
The results after the second time are equivalent to those of the first time. Even when the photocatalytic activated carbon sheet A is applied to a gas having a high concentration of acetaldehyde, it has sufficient initial removal performance without impairing the original adsorption performance of the activated carbon fiber. It was found that the removal performance could be maintained for a long time.

Example 2 20 parts by weight of the titania fiber and acrylic fiber pulp (acrylic fiber R-56F manufactured by Toyobo Co., Ltd. beaten using a single refiner: freeness 31)
0) 20 parts by weight and 10 parts by weight of polyester fiber (trade name: Tepils TJ04CN, fineness: 1.5 d, length: 5 mm, manufactured by Teijin Limited) were dispersed in water, and a sheet was prepared using a square paper machine. After dehydrating this sheet, 110 ° C
To obtain a sheet B.

Activated carbon fiber (manufactured by Nippon Kainol Co., Ltd.
ACF-1603-20) 20 parts by weight, the acrylic fiber pulp 20 parts by weight, and the polyester fiber 10 parts by weight were dispersed in water, and a sheet was prepared using a square paper machine. After dehydrating the sheet, a sheet C was prepared by hot pressing at 110 ° C.

The sheet B and the sheet C are laminated, and
The resultant was hot-pressed at ° C to obtain a photocatalytic activated carbon sheet D (the basis weight of the titania fiber and the activated carbon fiber was 20 g / m ² , respectively).

A 6 W black light as an excitation light source was placed in a 5 L Pyrex glass separable reaction vessel (capacity: 6.3 L), and a photocatalytic activated carbon sheet D cut to 10 cm × 10 cm was cut from the black light by 1 c.
It was arranged in a column at a distance of m. A fan was arranged for stirring the air in the reaction vessel. The photocatalytic activated carbon sheet D had sufficient flexibility and could be arranged in a columnar shape.

A predetermined amount of acetaldehyde was introduced into the reaction vessel in a short time so that the initial acetaldehyde concentration in the reaction vessel was 30 ppm. After the introduction 1
After 0 minute, the black light was turned on and the photocatalytic activated carbon sheet D was irradiated with light for 6 minutes. Thereafter, the black light was turned off and held for 14 minutes. The change in the concentration of acetaldehyde in the reaction vessel was measured by gas chromatography. Subsequently, the same operation was repeated five times in total. The results are shown in FIG.

From the results shown in FIG. 3, three minutes after the completion of the introduction, the concentration of acetaldehyde in the reaction vessel became 17 ppm. After turning on the black light and irradiating the photocatalytic activated carbon sheet D with light for 5 minutes, the concentration of acetaldehyde in the reaction vessel became 1 ppm or less. Repeat test results, 2
The results after the second time are the same as those of the first time, and the photocatalytic activated carbon sheet D has sufficient initial removal performance without impairing the original adsorption performance of the activated carbon fiber, and can maintain the removal performance for a long period of time. all right.

[0034]

The photocatalytic activated carbon sheet of the present invention is a photocatalytic activated carbon sheet using activated carbon fiber which is easily produced and obtained on an industrial scale, and is used for removing malodorous substances, harmful substances, mold and the like in living and working spaces. It has sufficient initial removal performance in the use of, for example, and can maintain the removal performance for a long period of time, and its industrial utility value is great.

[Brief description of the drawings]

FIG. 1 is a scanning electron micrograph of titania fibers used for a photocatalytic activated carbon sheet of the present invention.

FIG. 2 is a diagram showing a change in acetaldehyde concentration in a reaction vessel in Example 1.

FIG. 3 is a diagram showing a change in acetaldehyde concentration in a reaction vessel in Example 2.

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) D04H 1/42 A61L 9/00 C // A61L 9/00 9/01 B 9/01 9/16 D 9/16 9 / 18 9/18 B01D 53/36 H (72) Inventor Miaki Takeuchi 5-1 Sokai-cho, Niihama-shi, Ehime F-term (reference) in Sumitomo Chemical Co., Ltd. 4C080 AA05 AA07 AA10 BB02 BB08 CC01 HH05 JJ06 KK08 LL02 LL10 MM02 MM05 NN06 NN26 4D048 AA19 AA22 AB03 BA07X BA07Y BA45X BA45Y BB08 EA01 EA04 4G069 AA03 AA08 BA04A BA04B BA08A BA08B BA17 BA22A BA22B CA02 CA17 DA06 EA03A

Claims (3)

[Claims] 1. A photocatalytic activated carbon sheet comprising titania fibers and activated carbon fibers. 2. A photocatalytic activated carbon sheet comprising titania fibers, activated carbon fibers, and at least one fiber selected from the group consisting of vegetable fibers, synthetic resin fibers, inorganic fibers, and metal fibers. 3. The titania fiber has a basis weight of about 1 g / m ^2.
Photocatalyst activated carbon sheet according to claim 1 or 2, wherein the ~ about 500 g / m ^2.