JP2000117117A - Photocatalytic materials - Google Patents

Abstract

(57) [Problem] To provide a photocatalytic material excellent in photocatalytic performance and its aging durability. SOLUTION: 100 parts by weight of cement and specific surface area of 20 to
A photocatalyst material obtained by uniformly mixing 10 to 150 parts by weight of 300 m ² / g of titanium oxide.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photocatalyst material comprising a mixture of cement and titanium oxide, and more particularly to a photocatalyst material having excellent photocatalytic performance and sustainability due to titanium oxide.

[0002]

2. Description of the Related Art Techniques for removing contaminants in the air or water by utilizing the photocatalytic performance of titanium oxide have already been put into practical use. For example, Japanese Patent Application Laid-Open No. 7-171408 discloses a technique.
A photocatalyst material in which a photocatalyst such as titanium oxide is solidified with a binder such as cement has been proposed. Also, JP-A-9-26
No. 8509 proposes a concrete product having a two-layer structure of a base layer and a surface layer in which titanium oxide is mixed in the surface layer.

[0003] Among them, in an embodiment described in Japanese Patent Application Laid-Open No. 7-171408, titanium oxide, cement and water are mixed at once to form a coating material. Also, Japanese Patent Application Laid-Open No. 9-2
In the conventional photocatalytic cement products such as Japanese Patent No. 68509, when mixing cement as a binder and titanium oxide as a photocatalyst, cement and titanium oxide or further aggregate are premixed with a usual mortar mixer or concrete mixer. After that, water is added and kneaded to obtain mortar or concrete, which is further molded by casting, immediate demolding, press molding, etc., and cured to obtain a product.

Japanese Patent Laid-Open Publication No. Hei 10-180095 proposes a technique for improving the fluidity of a spray material by adding calcium carbonate fine powder to a photocatalyst spray material comprising cement and titanium oxide.

[0005]

However, in the conventional mixing method using such a mixer, stirring and mixing are performed at a relatively low speed, so that a mortar mixer and a concrete mixer which are usually used are ultrafine powders. There is a problem that certain titanium oxides cannot be uniformly dispersed and mixed. And since the titanium oxide was not uniformly dispersed, the obtained product was not able to sufficiently exhibit the photocatalytic function of the titanium oxide.

To improve the dispersion of titanium oxide, it is effective to extend the pre-mixing time and the kneading time. However, simply increasing the mixing or kneading time often results in a photocatalytic function,
In particular, the long-term durability of the photocatalytic function cannot be improved, and in this case, there is a problem that the productivity of the product is significantly reduced due to the prolonged mixing or kneading time.

In Japanese Patent Application Laid-Open No. Hei 10-180095, since fine powder of calcium carbonate is added, the surface of the photocatalyst becomes dense, and a sufficient effect of adsorbing harmful substances cannot be obtained.

An object of the present invention is to solve the above-mentioned conventional problems and to provide a photocatalyst material having excellent photocatalytic performance and long-term durability.

[0009]

Means for Solving the Problems The photocatalyst material of the present invention comprises:
100 parts by weight of cement and specific surface area of 20 to 300 m ² / g
And 10 to 150 parts by weight of titanium oxide are uniformly mixed.

[0010] The photocatalyst material of the present invention is excellent in photocatalytic performance, particularly its long-term durability, since cement and fine-grained titanium oxide having a specific surface area of 20 to 300 m ² / g are uniformly dispersed and mixed.

The photocatalyst material of the present invention further comprises 0.1 to 10 parts by weight of a water repellent and 0.1 to 10 parts by weight of a fluidizing agent with respect to 100 parts by weight of a total of cement and titanium oxide. ３００300 parts by weight pozzolanic substance 20-200 parts by weight, efflorescence can be suppressed by adding a water repellent, and molding workability is improved by adding a fluidizing agent, Is further enhanced. In addition, a mortar material having a photocatalytic function by blending fine aggregate is provided. In addition, the pozzolan compound improves the performance of removing harmful substances.

[0012]

Embodiments of the present invention will be described below in detail.

The photocatalyst material of the present invention is obtained by uniformly mixing cement and titanium oxide.

In the present invention, the cement is not particularly limited, and ordinary portland cement, early-strength portland cement, ultra-high-strength portland cement, moderately heated portland cement, sulfate-resistant portland cement, blast furnace cement, fly ash cement, silica cement , White portland cement, ultra-rapid hardening cement, oil well cement, low heat generation cement, alumina cement and the like.

As titanium oxide, anatase type titanium dioxide, rutile type titanium dioxide, metatitanic acid,
1 such as orthotitanic acid, hydrous titanium oxide, titanium hydroxide
Species or two or more species.

If the particle size of the titanium oxide is too large or too small, the uniform dispersibility is impaired. If the particle size is too large, the photocatalytic effect is inferior due to the small surface area. Therefore, the specific surface area of titanium oxide is 2
Those having a range of 0 to 300 m ² / g, preferably 30 to 250 m ² / g are used.

If the amount of titanium oxide is too small, sufficient photocatalytic performance cannot be obtained, and if the amount is too large, moldability and the like are impaired. To 150 parts by weight, preferably 20 to 70 parts by weight.

As described above, the photocatalyst material of the present invention may contain a water repellent and a fluidizing agent. Examples of the water repellent include silicone, modified silicon, polyurethane and specially modified polyester. Powdered water repellents such as copolymers, stearic acid resins, paraffin resins, active metal salts and fatty acid salts are preferred. If the amount of the water repellent is too small, a sufficient effect cannot be obtained.If the amount is too large, no further improvement in the effect can be expected. It is preferable to use 0.1 to 10 parts by weight based on 100 parts by weight of the total of cement and titanium oxide.

As the fluidizing agent, powdery fluidizing agents such as naphthalene sulfonic acid and melamine are suitable. For the same reason as described above, the amount of the fluidizing agent is preferably 0.1 to 10 parts by weight based on 100 parts by weight of the total of cement and titanium oxide.

The photocatalyst material of the present invention further comprises a pozzolanic substance such as blast furnace slag fine powder, silica fume, diatomaceous earth, fly ash, silica fine powder, silica silicate, activated zeolite, natural zeolite, etc. 20 to 200 parts by weight may be contained with respect to 100 parts by weight, whereby the hardened cement becomes porous and the adsorption characteristics are increased, and the harmful substances are easily adsorbed.
NO _X removal performance is improved.

The photocatalyst material of the present invention is used in an amount of 50 to 300 parts by weight based on a total of 100 parts by weight of cement and titanium oxide.
A mortar material containing fine parts of fine parts by weight, for example, silica sand, sea sand, mountain sand, crushed sand, or the like may be used. Further, a lightweight aggregate such as pearlite or shirasu balloon may be used. In this case, it is desired that the fine aggregate such as silica sand has a particle size of 85% or more that passes through a sieve having a mesh size of 5 mm.

The photocatalyst material of the present invention is characterized in that at least cement and titanium oxide are uniformly mixed among the constituent components. The `` homogeneous mixed state '' in the present invention is a state in which each powder particle is uniformly dispersed when observed with an electron microscope in a state of being kneaded with water, such a uniform mixed state is, for example, This can be achieved by mixing under the following mixing conditions.

[When only cement and titanium oxide are mixed] A high-speed stirring mixer having a rotation speed of about 500 to 2000 times / min. For 2 minutes or more, preferably 5 to 10 minutes [Cement, titanium oxide and fine aggregate, etc. Mixing with a high-speed stirring mixer having a rotation speed of about 500 to 2000 times / minute for 2 minutes or more, preferably 5 to 10 minutes. As the product is shipped in a state in which the agent and further fine aggregate are evenly mixed, in the case of on-site construction and production of blocks, etc., after adding fine aggregate as necessary and mixing gently It is only necessary to add and knead with water, and the workability on site and productivity are greatly improved.

[0024] Such photocatalyst cement product produced using a photocatalytic material of the present invention, decomposing and removing harmful substances in the air such as NO _X and SO _X by photocatalytic function, methyl mercaptan, formaldehyde, methane, ammonia Deodorization of malodorous substances such as trichlorethylene, tetrachlorethylene, 1,1,1-
A high photocatalytic function such as decomposition of trichloroethane and chlorophenol can be maintained for a long period of time, and its industrial value is extremely high.

[0025]

The present invention will be described more specifically below with reference to examples and comparative examples.

Examples 1-3 Normal Portland Cement (Mitsubishi Materials Corporation)
50 parts by weight and titanium oxide (anatase type, specific surface area 17
0 m ² / g) 50 parts by weight of a high-speed stirring mixer (Lady Ge mixer, manufactured by Matsuzaka Trading Co., Ltd., type: FM130, rotation speed 12)
(00 revolutions / minute). Hereinafter, this mixing is referred to as “high-speed mixing”. The resulting mixture 100
200 parts by weight of No. 4 silica sand as fine aggregate is added to the parts by weight and mixed with a Hobart mixer (manufactured by Maruto Seisakusho Co., Ltd., type: C138A, rotation speed: 140 rotations / minute) for 3 minutes (hereinafter referred to as "low speed mixing"). ), 55 parts by weight of water was added, and the mixture was kneaded for 3 minutes. At this time, the obtained mortar was observed with a scanning electron microscope in order to examine the mixing state of the powder.

The obtained mortar is poured into a mold,
A molded body of cm × 10 cm × 3 cm was produced. This molding
After curing the body in wet and air, NO shown in FIG._XRemoval performance measurement equipment
Of the test specimen_XThe removal performance was measured. This N
O_XThe removal performance measuring device is NO _XA standard gas containing
From the light source 3 to the specimen 2
And comes into contact with the specimen 2 by switching the solenoid valve 4.
NO in gas before and after_XNO concentration_XMeasure with automatic measuring instrument 5
NO_XThe removal rate is determined.

After exposing the specimen outdoors for one year,
The NO _x removal rate was measured in the same manner.

Table 1 shows the observation results of the powder dispersibility of the mortar and the measurement results of the NO _X removal rate (initial and one year later) of the test specimen.

Comparative Examples 1 to 3 In Examples 1 to 3, cement, titanium oxide and silica sand were mixed at low speed with a Hobart mixer for the time shown in Table 1 without high-speed mixing by a high-speed stirring mixer, and water was added. Table 1 shows time kneaded except similarly prepared mortar, perform molding, similarly investigated powder dispersibility of the mortar, the NO _X removal rate of the specimen with the results shown in Table 1.

[0031]

[Table 1]

As it is apparent from Table 1, in Examples 1 to 3 were uniformly dispersing titanium oxide by high speed mixing, both exhibited high NO _X removal performance was achieved, less its aging. On the other hand, in Comparative Examples 1 to 3 in which high-speed mixing was not performed, NO _X was increased by increasing the mixing time.
Although the improvement of the removal performance is recognized, it is inferior to that of the example and the deterioration over time is large.

Examples 4 to 8 Concrete blocks of immediate demolding comprising two layers of a surface mortar containing titanium oxide and a base concrete not containing titanium oxide were prepared.

First, 100 parts by weight of Portland cement, 170 parts by weight of crushed stone, 240 parts by weight of sand and 31 parts by weight of water were mixed and kneaded to obtain a base layer concrete.

Separately, 50 parts by weight of cement shown in Table 2
Titanium oxide (anatase type, specific surface area 230 m ² / g)
50 parts by weight and 320 parts by weight of No. 4 silica sand were mixed with a high-speed stirring mixer (Lady Ge mixer, manufactured by Matsuzaka Trading Co., Ltd., type: FM130,
The mixture was mixed at a high speed of 1200 rpm for 5 minutes to obtain a mixture. In Example 8, 1.0 part by weight of a silicon-based water repellent (AQUA SEAL 10PS: manufactured by Sumitomo Seika) was further added. 55 parts by weight of water was added to 100 parts by weight of this mixture, and low-speed mixing was carried out with a Hobart mixer (manufactured by Maruto Seisakusho Co., Ltd., type: C138A, rotation speed: 140 rotations / minute) for 3 minutes to obtain a surface mortar.

The base concrete is placed in a 10 cm × 20 cm formwork, subjected to pressure vibration molding, a surface mortar is placed thereon, and a mold plate is placed thereon. 0.5 kg / cm ² , frequency 3140 rpm,
After performing an amplitude of 1.5 mm and a pressure vibration time of 3 seconds), the mixture was cured to obtain a test block having a length of 20 cm, a width of 10 cm, and a height of 6 cm. The thickness of the surface layer portion of this block was 7 mm.

[0037] For the obtained specimen, examined NO _X removal performance in the same manner as in Example 1 and the results are shown in Table 2.

Comparative Example 4 In Example 4, in preparing the surface mortar, cement, titanium oxide and silica sand were mixed at a low speed for 10 minutes using a Hobart mixer without high-speed mixing, and then water was added and mixed for another 3 minutes. to produce a specimen in the same manner except that, similarly examined NO _X removal performance, and the results are shown in Table 2.

[0039]

[Table 2]

[0040] As apparent from Table 2, in Examples 4-8 all showed a high NO _X removal performance. On the other hand, in Comparative Example 4, both NO _X removal performance is inferior in aging in the initial.

In Example 4, using a product in which cement of surface layer mortar, titanium oxide and silica sand were previously mixed at high speed, the productivity was examined by comparing the mixing operation time with Comparative Example 4, and the results are shown in Table 3. Thus, in Example 4, Comparative Example 4
It can be seen that the productivity is improved by about 30% as compared with.

[0042]

[Table 3]

[0043]

As described above in detail, according to the present invention, there is provided a photocatalyst material which has remarkably good photocatalytic performance and sustainability, and is effective for improving the productivity of cement products.

[Brief description of the drawings]

1 is a configuration diagram showing an NO _X removal performance measuring apparatus used in Examples and Comparative Examples.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Cylinder 2 Specimen 3 Light source 4 Solenoid valve 5 NO _X automatic measuring instrument

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hideo Tahara 1-297 Kitabukurocho, Omiya-shi, Saitama Mitsubishi Materials Corporation Cement Research Institute (72) Inventor Hiroshi Yamada 1-297 Kitabukurocho, Omiya-shi, Saitama Mitsubishi Materials 4G012 MA00 PB03 4G069 AA08 BA48A BC50A BC50B CA12 CA13 CA17 DA05

Claims (5)

[Claims] 1. 100 parts by weight of cement and a specific surface area of 20 to
A photocatalyst material characterized by being uniformly mixed with 10 to 150 parts by weight of 300 m ² / g titanium oxide. 2. The photocatalytic material according to claim 1, wherein the water repellent is contained in an amount of 0.1 to 10 parts by weight based on 100 parts by weight of the total of cement and titanium oxide. 3. The photocatalyst material according to claim 1, wherein the photocatalytic material contains 0.1 to 10 parts by weight of a fluidizing agent based on 100 parts by weight of the total of cement and titanium oxide. 4. A photocatalyst material comprising 50 to 300 parts by weight of fine aggregate with respect to 100 parts by weight of a total of cement and titanium oxide. 5. A photocatalytic material comprising 20 to 200 parts by weight of a pozzolanic substance based on 100 parts by weight of a total of cement and titanium oxide.