JP2001303494A - Adsorbing photocatalytic inorganic sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a noncombustible adsorbing photocatalytic inorganic sheet effective for efficiently decomposing a harmful substance to cause the air pollution and odor generation and making the substance harmless. SOLUTION: The objective adsorbing photocatalytic inorganic sheet effective for efficiently decomposing a harmful substance to cause the air pollution and odor generation and making the substance harmless is produced by preparing a composite sheet using all components comprising an organic pulp, an adsorbent, a photocatalyst, an inorganic fiber, an inorganic substrate forming component and a polymer flocculant or using a material group composed of the above components excluding the organic pulp and the polymer flocculent by a semi-dry method or a wet method in a manner to obtain the sheet containing a larger amount of the adsorbent than the photocatalyst and baking the obtained sheet at >=500 deg.C to make the sheet noncombustible and increase the strength of the sheet.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an adsorptive photocatalytic inorganic sheet which can decompose harmful substances such as air pollutants and odorous substances by utilizing adsorption and photocatalytic reaction, and more particularly to formation of inorganic fibers and inorganic support. The present invention relates to an adsorptive photocatalytic inorganic sheet having a component, in which an adsorbent and a photocatalyst are efficiently held in a sheet, and having excellent strength and an excellent effect of remediating environmental pollution.

[0002]

2. Description of the Related Art Recently, environmental problems have seriously affected daily life, and there is an urgent need for improvements. As one of the improvement measures, a harmful substance remover is used, and an adsorbent such as activated carbon, silica, alumina and metal oxide is used for this.As the harmful substance is adsorbed by the adsorbent, There have been many problems in use, such as the adsorption capacity gradually decreasing. In order to solve this problem, a method for removing harmful substances using a photocatalyst has recently been developed. Decomposition of harmful substances by a photocatalyst such as titanium oxide or zinc oxide is a photocatalytic oxidation action of harmful substances by these photoexcitations, and thus lasts for a long time. This is a great advantage of the photocatalyst as compared with the adsorbent, but the photocatalyst has a drawback that the reaction efficiency is inferior due to low adsorbability.
In order to remedy these drawbacks, adsorbents and photocatalysts have already been combined. This is a very rational method, since low-concentration harmful substances can be concentrated with an adsorbent and efficiently decomposed by a photocatalyst present in the vicinity. Activated carbon is often used as an adsorbent, but has the disadvantage that when it is combined with a photocatalyst, it is gradually degraded by an oxidation reaction.
In addition, since effective adsorbents and photocatalysts are powders, it is difficult to hold them in a sheet shape, and organic binders such as resin emulsions are used. It cannot be prevented. For use outdoors as an air pollutant remover or indoors as an odor remover, a nonflammable adsorptive photocatalyst sheet that is particularly excellent in durability is required.

[0003]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and as a result, a sheet molded by a semi-dry method has been calcined at 500 ° C. or higher, or an inorganic sheet has been formed on a wet-formed sheet. A binder treatment was performed, and the mixture was fired at 500 ° C. or higher to completely incinerate and remove organic substances, thereby completing a non-combustible adsorptive photocatalyst sheet having excellent durability. That is, the present invention provides: Presence of organic fibers such as wood pulp and linter pulp, inorganic adsorbents such as zeolite and silica,
A small amount of water is added to a mixture of a photocatalyst such as titanium oxide or zinc oxide, an inorganic fiber such as ceramic fiber or glass fiber, and an inorganic support-forming component such as silica sol or alumina sol, and the mixture is kneaded well. 1. A method for producing an adsorptive photocatalytic inorganic sheet from which organic matter has been removed by spreading the sheet as uniformly as possible, pressing it, and then heating it to 500 ° C. or higher; Add a positive coagulant such as polydiallyldimethylammonium chloride, cationic polyacrylamide or polyvinylamine to organic fibers such as wood pulp or linter pulp, and then add an inorganic adsorbent, photocatalyst and inorganic fibers or a water suspension composed of these three. Add a liquid, further add a negative coagulant such as anionic polyacrylamide or polyacrylic acid, and impregnate or spray an inorganic support-forming component such as alumina sol or silica sol on a wet-sheeted sheet or on a dried sheet. The present invention relates to a method for producing an adsorptive photocatalytic inorganic sheet from which organic matter has been removed by heating at 500 ° C. or higher after squeezing by adding a method.

[0004]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, components relating to the adsorptive photocatalytic inorganic sheet of the present invention, and a method for producing the same will be described in detail.

The inorganic adsorbents according to the present invention include zeolite, activated clay, zinc oxide, alumina, sepiolite, halloysite, and composites thereof.
In particular, zeolite can adjust its pore size to maximize the adsorption efficiency for various harmful substances,
It is advantageously used as an inorganic adsorbent.

The photocatalyst of the present invention includes metal oxides such as titanium oxide, zinc oxide and cerium oxide.
In particular, titanium oxide is excellent in stability, safety, photocatalytic high resolution, etc., is most suitable for use around houses and roads, and is advantageously used as a photocatalyst according to the present invention.

The inorganic fibers used in the present invention include ceramic fibers, glass fibers, slag fibers, and asbestos.
Ceramic fibers excellent in stability, safety, strength and the like are advantageously used.

As the inorganic support-forming component according to the present invention, alumina sol, silica sol, sodium phosphate and the like can be mentioned, and the alumina sol having the most suitable particle diameter and affinity with other materials is advantageously used.

The organic pulp of the present invention is a fibrous substance such as wood pulp, linter pulp, and synthetic pulp. Natural pulp which can contribute to a high yield of inorganic powder and is easily fibrillated is advantageous. Used.

For semi-dry molding, a sheet molding machine for a fiberboard or cement board can be used. Alternatively, a net can be placed on a metal plate having a large number of holes, and the kneaded raw material mixture can be spread as evenly as possible on the metal plate, and pressed with a test press to form a sheet. 500 sheets prepared
Calcination was performed in an electric furnace controlled at a constant temperature of not less than ° C. to obtain an adsorptive photocatalytic inorganic sheet.

[0011] Wet papermaking includes a round paper machine, a fourdrinier paper machine,
A twin wire paper machine can be used. The prepared sheet was impregnated or sprayed with a dispersion of the inorganic support-forming component, and then fired in an electric furnace adjusted to a constant temperature of 500 ° C. or higher to obtain an adsorptive photocatalyst sheet.

[0012]

Next, the present invention will be described specifically with reference to examples. In light of the common general knowledge in the art, it is clear that the present invention is not limited to the last part of the experimental conditions used in the examples described below.

Example 1 1.0 part of linter pulp beaten to about 350 ml of CSF, zeolite (manufactured by Tosoh Corporation,
HSZ-320NAA) 4.0 parts, titanium oxide (manufactured by Ishihara Sangyo Co., ST-31) 2.0 parts, ceramic fiber (manufactured by Isolite Industries, Kao Wool Bulk LS) 3.0 parts and alumina sol (manufactured by Nissan Chemical Industries, Ltd.) Alumina sol-52
0) 4.0 parts and 7.0 parts of water were added and kneaded with a kneader. An 80-mesh wire mesh is placed on a stainless steel plate having holes at intervals of about 10 mm, and the kneaded raw material is spread as evenly as possible on this, and the kneaded material is 3.5 kP using a handsheet press.
a Pressed for 5 minutes. The resulting sheet was calcined at 700 ° C. for 20 minutes to obtain the adsorptive photocatalytic inorganic sheet of Example 1 having a basis weight of about 250 g / m ² .

Example 2 An adsorptive photocatalytic inorganic sheet of Example 2 was prepared in the same manner as in Example 1 except that the amount of linter pulp was changed to 0 parts.

Example 3 The adsorbent photocatalytic inorganic sheet of Example 3 was prepared in the same manner as in Example 1 except that zeolite was changed to 3.0 parts and titanium oxide was changed to 3.0 parts. Prepared.

Example 4 25 g of a 0.1% aqueous solution of polydiallyldimethylammonium chloride was added to 10 g of a 4% aqueous suspension of linter pulp beaten to about 350 ml of CSF, and 2.4 g of zeolite 3 minutes later. ,
65 g of an aqueous suspension containing 1.2 g of titanium oxide and 1.5 g of ceramic fibers were added, and 25 g of a 0.1% negative flocculant (HI-351 manufactured by Kurita Water Industries Ltd.) was added.
A sheet was prepared in accordance with ISP 8209, and the sheet was impregnated with alumina sol as a dispersion of the inorganic support-forming component. This was pressed and fired in the same manner as in Example 1 to obtain the adsorptive photocatalytic inorganic sheet of Example 4.

Example 5 The adsorptive photocatalyst sheet of Example 5 was obtained in the same manner as in Example 4 except that 1.8 g of zeolite and 1.8 g of titanium oxide were used.

[Embodiment 6] In Embodiment 4, the CSF is about 3
An adsorbent photocatalytic inorganic sheet of Example 6 was obtained in the same manner as in Example 4 except that LBKP beaten to about 270 ml of CSF was used instead of linter pulp beaten to 50 ml.

[Example 7] In Example 5, CSF was used instead of linter pulp beaten to about 350 ml of CSF.
An adsorbent photocatalytic inorganic sheet of Example 7 was obtained in the same manner as in Example 5 except that LBKP beaten to about 270 ml was used.

Comparative Example 1 The adsorptive photocatalytic inorganic sheet of Comparative Example 1 was prepared in the same manner as in Example 1, except that 2.2 parts of zeolite and 4.4 parts of titanium oxide were used. Was prepared. This sample was used as the adsorptive photocatalytic inorganic sheet of Comparative Example 1.

Comparative Example 2 An adsorbent photocatalytic inorganic sheet of Comparative Example 2 was prepared in the same manner as in Example 1 except that zeolite was changed to 0 parts and titanium oxide was changed to 6.6 parts. did. This sample was used as the adsorptive photocatalytic inorganic sheet of Comparative Example 2.

Comparative Example 3 In Example 4, 0.1%
25 g of polydiallyldimethylammonium chloride in 5
An adsorbent photocatalytic inorganic sheet of Comparative Example 3 was prepared in the same manner as in Example 4 except that 0 g and 25 g of 0.1% negative flocculant were changed to 0 g. This sample was used as the adsorptive photocatalytic inorganic sheet of Comparative Example 3.

Comparative Example 4 In Example 4, 25 g of 0.1% polydiallyldimethylammonium chloride was added in an amount of 0 g.
The adsorptive photocatalytic inorganic sheet of Comparative Example 4 was prepared in the same manner as in Example 4, except that the amount of the 25% 0.1% negative coagulant was changed to 50 g. This sample was used as the adsorptive photocatalytic inorganic sheet of Comparative Example 4.

Comparative Example 5 The adsorptive photocatalytic inorganic sheet of Comparative Example 5 was prepared in the same manner as in Example 4 except that zeolite was changed to 1.2 g and titanium oxide to 2.4 g. . This sample was used as the adsorptive photocatalytic inorganic sheet of Comparative Example 5.

Comparative Example 6 An adsorptive photocatalytic inorganic sheet of Comparative Example 6 was prepared in the same manner as in Example 4 except that zeolite was changed to 0 g and titanium oxide to 3.6 g. This sample was used as the adsorptive photocatalytic inorganic sheet of Comparative Example 6.

Comparative Example 7 The adsorptive photocatalytic inorganic sheet of Comparative Example 7 was prepared in the same manner as in Example 4 except that zeolite was changed to 3.6 g and titanium oxide was changed to 0 g. This sample was used as the adsorptive photocatalytic inorganic sheet of Comparative Example 7.

The adsorptive photocatalytic inorganic sheets obtained in Examples and Comparative Examples were tested by the following method. Table 1 shows the results when no ultraviolet rays were irradiated, and Table 1 shows the results when ultraviolet rays were irradiated. Are shown in Table 2.

[Yield of inorganic substance]
It was baked for 20 minutes in an electric furnace at 00 ° C. and determined from the residual ash content.

[Strength of Inorganic Sheet] A compressive strength test (ring crush method) was measured in accordance with Tappi T 818-87.

[Adsorption / Photocatalytic Decomposition] 2.5 cc stainless steel reaction vessel having a quartz cover
After installing the adsorptive photocatalytic inorganic sheets of Examples and Comparative Examples having a size of cm × 2.5 cm, 125 p
Nitric oxide or formaldehyde was injected with a microsyringe to pm. At predetermined time intervals, the concentration of nitric oxide or formaldehyde in the reaction vessel was measured. Nitrogen monoxide was analyzed using a chemiluminescent NOx analyzer, and formaldehyde was analyzed using gas chromatography. In addition, the same experiment was performed by irradiating a sample with an ultraviolet lamp having a wavelength of 365 nm and 4 watts from a height of 10 cm. The adsorptivity was evaluated from the initial reduction rate of nitric oxide or formaldehyde, and the photocatalytic degradation was evaluated from the concentration after 1 hour.

[0031]

[Table 1]

[0032]

[Table 2]

[0033]

As is clear from the above description,
The adsorptive photocatalytic inorganic sheet according to the present invention comprises a noncombustible adsorptive photocatalytic inorganic sheet comprising an adsorbent, a photocatalyst, inorganic fibers and a support-forming component, or an organic fiber, an adsorbent, a photocatalyst and inorganic fibers by a dual polymer system. After the aqueous suspension is appropriately agglomerated, a wet-formed sheet or a dried sheet is impregnated or sprayed with a support-forming component, heated to 500 ° C. or higher, and calcined, and the adsorbent photocatalytic inorganic sheet is fired. In recent years, since it has excellent decomposability of harmful substances such as air pollutants and volatile organic compounds, and has excellent post-processability of sheets such as honeycomb structure molding or sticking to metal plates and various building materials, it has become a social problem in recent years. High-efficiency adsorption photolysis of NOx, SOx, hydrocarbons, etc. by attaching to the side wall of traffic congestion points in urban expressways and urban areas Air purification, indoor air purification by highly efficient adsorption photolysis of volatile organic compounds such as formaldehyde and toluene, decay odor, aging odor and other living unpleasant substances from interior materials of houses, and miniaturization and thinning in recent years It is highly useful as a filter member for air purifiers for home use and on-vehicle use where there is a demand. In many cases, the above contaminants are present at low concentrations, so it is important to first efficiently collect and concentrate them with an adsorbent.
When concentrated, the contaminants are decomposed with high efficiency by the photocatalyst present near the adsorbent. Therefore, when the weight of the adsorbent in the sheet is larger than the weight of the photocatalyst, an adsorptive photocatalytic inorganic sheet having particularly excellent performance is provided. Furthermore, the adsorptive photocatalytic inorganic sheet of the present invention, which is characterized by being nonflammable, is close to a road where there is a risk of a car fire due to a collision, a photocatalytic excitation light source with heat generation, and a risk of discharge ignition. It can be used in the vicinity of electrical equipment such as light sources and air conditioners, and has the advantage of achieving flame retardance if used in the interior of a house. is there.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (Reference) B01J 37/02 301 B01J 37/08 37/08 D21H 13/38 D21H 13/38 17/67 17/67 21 / 14 Z 21/14 27/00 C 27/00 B01D 53/36 JF term (reference) 4C080 AA05 AA07 AA10 BB02 CC01 HH08 JJ06 KK08 MM02 NN02 NN03 NN04 NN06 QQ03 4D048 AA06 AA19 AA22 AB03 BA03X BA07X BA41XBB04X04 AA03 AA08 AA11 BA01A BA01B BA02A BA04A BA04B BA07A BA07B BA29A BA29B BA48A BB14A BC02A CA10 CA17 EA07 EA12 EA13 FA03 FB06 FB15 FB24 FB30 FC07 4L055 AA08 AF05 AF08 AG17 AG10 AG28 AG71 AG94 BD12

Claims (2)

[Claims] 1. An inorganic adsorbent, a photocatalyst, an inorganic fiber and an inorganic support-forming component, wherein the inorganic adsorbent is 50% of the photocatalyst.
The adsorptive photocatalytic inorganic sheet occupying the above. 2. After adding a positive coagulant to the water-dispersed organic fiber,
Immersion of the inorganic support-forming component in a sheet obtained by adding an inorganic adsorbent, a photocatalyst and an inorganic fiber or an aqueous suspension composed of the three, and further adding a negative coagulant to the sheet, or by drying the sheet, An adsorptive photocatalytic inorganic sheet which has been subjected to a treatment or spraying treatment and further calcined at 500 ° C. or higher.