KR100913076B1 - TiO2 SLURRY HAVING HIGH PHOTO-ACTIVITY AND METHOD OF MANUFACTURING CONCRETE/TIO2-STRUCTURE FOR PURIFYING POLLUTED WATER - Google Patents

Abstract

The present invention relates to a method for manufacturing a contaminated water purification concrete / TiO ₂ structural material having excellent economic efficiency and purification efficiency by using a TiO ₂ slurry having a high photoactivity, more specifically, TiO ₂ photocatalyst on a concrete block coating is eoryeowoona, in this method a dispersing agent to the TiO ₂ photocatalyst, a surfactant, a binder, a plasticizer and concrete this followed by the addition of substances such as a solvent to prepare a TiO ₂ photocatalyst slurry to a solid bonded to the concrete block surface slurry The present invention relates to a method of manufacturing a structural material having an excellent contaminant purification function by coating on a block.

The present invention per slurry solids consisting of 50 to 70% by weight of TiO ₂ powder, 5 to 8% by weight of dispersant, 1 to 5% by weight of surfactant, 17 to 40% by weight of binder and 1 to 20% by weight of plasticizer and 100 parts by weight of the solid It is characterized by mixing 100 to 350 parts by weight of the solvent.

Photocatalyst, Purification, Contaminated Water, Coating, Slurry, TiO2, Concrete

Description

TiO2 slurry having high photoactivity and method for producing contaminated water / concrete / TioO2 structural material

The present invention relates to a coating slurry having a high photoactivity and a method for manufacturing a contaminant purification material having excellent economic efficiency and purification efficiency by using the same, and more specifically, coating TiO ₂ photocatalyst on a concrete block. eoryeowoona, so that in this way the addition of materials such as a dispersing agent, a surfactant, a binder, a plasticizer and a solvent to the TiO ₂ photocatalyst to provide a slurry and TiO ₂ photocatalyst using the slurry to a solid bonded to the concrete block surface The present invention relates to a method of manufacturing a structural member having a good contaminant purification function by coating.

Recently, there is a lot of interest in the purification of polluted water as well as the regulation of wastewater pollutant caused by the rapid development of various industries such as manufacturing industry, animal husbandry, agriculture and mining industry. Methods for removing contaminants in water include biological treatment methods using microorganisms, activated sludge method, activated carbon adsorption method, and degassing method using physicochemical reactions of filtration, flocculation, precipitation or adsorption. However, in the case of microbial treatment method, the processing speed is very slow, and the conditions for satisfying the biological activity are required. In addition, when the physicochemical reaction is used, a large-scale facility is required for purification, and the purification process is complicated. In addition, the purification efficiency is relatively low, the purification cost is high, there are problems such as incineration of sludge generated after the purification treatment, the generation of secondary pollutants in the decomposition process. Therefore, in order to solve these problems, a lot of research has recently been conducted on techniques for removing contaminants in water by using an advanced oxidation process.

Advanced oxidation technology refers to a technology that decomposes organic contaminants in water into CO ₂ or H ₂ O, which is harmless to the environment, using OH ^- radicals, which show stronger oxidation than ordinary oxidants.

OH ^- radicals have a very high reaction rate and can react with most organic compounds. These advanced oxidation techniques include ultraviolet irradiation to ozone (O ₃ ) and hydrogen peroxide, fenton oxidation using iron salt (Fe II) and hydrogen peroxide, and ultraviolet light to semiconducting compounds such as TiO _2. , UV) irradiation to cause photolysis.

Among them, the photocatalytic decomposition process technology using a semiconducting compound attracts a lot of attention as a method of avoiding the problems caused by the existing water treatment method while using a powerful OH ^- radical. This technology currently uses semiconducting compounds such as TiO ₂ , CdS, KTaO ₂ , SrTiO ₃ , ZnO, and WO ₃ .

Among the compounds, ZnO has a very high oxidizing power but lacks resistance to acids or alkalis, and WO ₃ has a good photodegradation reaction even in light having a wavelength close to visible light, but relatively low oxidation power, and SrTiO ₃ has excellent photodegradation properties. However, manufacturing costs are high. However, TiO ₂ on anatase is currently most widely used because it has superior advantages in chemical resistance, irradiation light reactivity, oxidation power, practicality, and the like compared to other photocatalytic compounds.

Therefore, when the TiO ₂ photocatalyst on the anatase is used for wastewater treatment, high treatment efficiency can be obtained.

However, in the case of using the above-described powder form of TiO ₂ in the contaminated water treatment field, the work is performed by suspending the powder in contaminated water and irradiating light, and at this time, to prevent the loss of powder due to the flow of contaminated water. Additional facilities, costs and time are needed to recover the photocatalytic powder used for the purpose.

Therefore, immobilization of the photocatalyst to ensure that the powder is not suspended but fixed in a fixed position is essential in terms of facilities, cost and time. In general, in order to fix the photocatalyst, a method of coating the photocatalyst on a carrier having a surface state that is easy to carry the photocatalyst and does not significantly reduce the specific surface area of the photocatalyst is used.

Among the carriers that can be used for this purpose, materials such as synthetic zeolite, alumina and cordierite are expensive, and thus, it is difficult to use them in a large quantity for a lake block for the purification of river water in addition to the wastewater treatment for a specific use. Therefore, the photocatalyst can be easily coated even though the pores are not formed more than necessary, and can be easily used economically and can provide an advantageous carrier for use in shore blocks or river beds for the purification of river water. By immobilizing the photocatalyst powder on the carrier, it is necessary to increase the photolytic activity, stability and economic efficiency in particular.

In order to coat the photocatalyst on the carrier, a process of preparing the photocatalyst in the form of a slurry and coating the surface of the carrier is required. When the bonding force between the carrier and the photocatalyst is small, contaminated water may cause the photocatalyst to fall off from the carrier surface. Therefore, it is necessary to provide a slurry composition which can be coated with sufficient strength when the photocatalyst is coated on the surface of the carrier, but when the slurry is coated, cracks are formed in the coating layer or the bonding strength thereof is insufficient. As a result, it is difficult to find a slurry composition that satisfies these requirements.

In addition, even if the composition containing the photocatalyst is coated on the surface of the carrier, it is difficult to find the meaning of coating the photocatalyst because it is difficult to use as a high performance carrier for treating contaminated water because the photocatalytic property is greatly deteriorated when it is not in the anatase state. do.

Therefore, the photocatalyst should be strongly bonded to the surface of the carrier, and the photocatalyst should be present in such a form that the photocatalyst properties are not significantly degraded.

The present invention is to solve the above-mentioned problems of the prior art, according to one aspect of the present invention, when coating a photocatalyst on a concrete carrier, as well as having a sufficient bonding strength, the characteristics of the coating does not significantly degrade the high performance slurry Is provided.

In addition, according to another aspect of the present invention, there is provided a method for producing a concrete / TiO ₂ structural material for contaminated water purification excellent in photocatalytic activity by coating the slurry on the carrier so that the photocatalytic activity of the prepared carrier is not lowered.

The high performance slurry of the present invention for solving the above problems consists of 50 to 70% by weight of TiO ₂ powder, 5 to 8% by weight of dispersant, 1 to 5% by weight of surfactant, 17 to 40% of binder and 1 to 20% by weight of plasticizer. It is characterized by mixing the slurry solids and 100 to 350 parts by weight of the solvent per 100 parts by weight of the solids.

In this case, the TiO ₂ powder is preferably greater than the proportion of the 70% anatase TiO ₂ as a photocatalyst powder.

In addition, the TiO ₂ powder is advantageously a particle size of 50nm or less.

In addition, the dispersant is alpha-terpineol (α-terpineol), the surfactant is Photo-Flo200 (Photo-Flo200), ethoxylated nonylpheonl, ethoxylated tridecyl alcohol ( Ethoxylated tridecyl alcohol, sodium stearate, sodium disopropylnaphtalene sulfonate and dodecyltrimethylammonium chloride, the binder is selected from polyvinyl alcohol, polyvinyl alcohol Polyvinyl butyral, polymethyl methacrylate, paraffin, wax emulsions and microcrystalline waxes are selected from the plasticizer, and the plasticizer is polyethylene glycol ), Ethylene glycol, diethylene glycol, triethylene glycol (Triethylene glycol), tetraethylene glycol (Tetraethylene glycol), glycerol (Glycerol), dibutyl phthalate (Dibutyl phthalate) and dimethyl phthalate (Dimethyl phthalate), the solvent is ethanol (Ethanol), toluene (Toluene), methanol (Methanol), Butanol, Chloroform, Dichloromethane, Ethylacetate, Hexane, Diethylehter, Acetonitrile, Acetonitrile, Benzene or these It is effective to be a mixture of two or more of them.

As another aspect of the present invention, a method of coating a slurry having the above favorable conditions on a carrier includes 50 to 70 wt% of TiO ₂ powder, 5 to 8 wt% of a dispersant, 1 to 5 wt% of a surfactant, and 17 to 40 wt% of a binder. Preparing a slurry by mixing 100% by weight of a slurry per 100 parts by weight of the slurry solids and 100% by weight of the solids of the slurry; Coating the prepared slurry on a concrete block surface; Drying the slurry coated carrier; And firing the dried structural material (carrier + slurry).

In this case, the support is preferably a concrete block.

In addition, the step of firing the dried structural member (carrier + slurry), the temperature of the carrier to a firing temperature of 300 ~ 800 ℃ at a rate of 10 ℃ / min or less consists of the process of maintaining at a firing temperature for 3 hours or more It is preferable.

According to the present invention, the high performance TiO ₂ capable of obtaining sufficient photocatalytic properties as well as excellent bonding strength with the concrete block carrier. A slurry and a concrete / TiO ₂ structural material for treating contaminated water coated with a photocatalyst layer are provided through the slurry.

Therefore, according to the present invention, it is possible to obtain a structural material which is very effective in treating various contaminants, especially fluid phase contaminants.

Hereinafter, the present invention will be described in detail.

The inventors of the present invention, when the photocatalyst layer is coated on the carrier through the slurry, in order to exhibit excellent performance, the catalyst properties of the photocatalyst included in the slurry should be excellent, as well as they are uniformly dispersed and strongly on the surface of the carrier. It has to be combined and has reached the present invention through in-depth research to find slurry compositions that meet these conditions.

That is, the slurry composition of the present invention is characterized in that the TiO ₂ powder for photocatalyst is mixed with TiO ₂ powder having anatase phase of 70% or more, and a dispersant, a surfactant, a binder, a plasticizer and a solvent in an appropriate ratio. Each of the components and the composition ratio of the components are those necessary to solve the problems of the present invention will be described in detail as follows.

TiO ₂  powder

The TiO ₂ powder is a photocatalyst material necessary for treating a contaminant such as contaminated water by the carrier having photocatalytic properties when the slurry composition is coated on the carrier. In order for the carrier to sufficiently exhibit the photocatalytic properties, the TiO ₂ powder should be included in an amount of 50 wt% or more based on the content of the remaining components except the solvent in the slurry composition. However, when the TiO ₂ powder is excessively added, the content of the other components is relatively decreased, so that it is difficult to sufficiently obtain a dispersing effect, bonding strength, and the like. Therefore, the TiO ₂ powder may not be added in excess of 70% by weight. Therefore, the TiO ₂ powder in the slurry composition of the present invention is preferably contained 50 to 70% by weight of the components (hereinafter referred to as slurry solids) excluding the solvent.

In addition, the TiO ₂ powder included in the slurry composition has a sufficient specific surface area and preferably has a particle size of 50 nm or less so as to maintain high performance.

Further, while the TiO ₂ powder, it is necessary a proportion of the anatase 70% by weight or more. This is because a decrease in the ratio of the anatase phase and an increase in the ratio of the rutile phase lower the photocatalytic efficiency. In particular, as will be described later, the slurry composition of the present invention may undergo a process of being calcined at a high temperature after coating on a carrier, and may generate a stable rutile phase at a high temperature in the process, and even if cooled, the rutile phase may be transformed back into an anatase phase. Since this is very low, a reaction close to an irreversible reaction occurs.

Therefore, it is hardly expected that the ratio of the anatase phase in the coating layer on the carrier will increase than the ratio contained in the slurry. Therefore, the ratio of anatase contained in the slurry should be more than the ratio that can be tolerated in the final product. According to the results of the inventors of the present invention, the ratio of the required anatase phase in the carrier should be 70% by weight or more. Therefore, in consideration of the case where the anatase phase contained in the slurry is calcined without changing into a rutile phase at all, the ratio of the anatase phase is preferably 70% by weight or more. In addition, in view of a slight phase change, the ratio of the anatase phase is preferably 80% by weight or more.

Dispersant

The dispersant is TiO ₂ are uniformly dispersed and serves to minimize the deviation of the TiO ₂ content in the coating layer. As a result, a uniform photocatalytic effect can be obtained regardless of the position. The dispersant should be selected in consideration of the properties of the other additives, alpha-terpineol (α-terpineol) is preferred in the present invention.

In order to sufficiently obtain the dispersing effect by the dispersant, the content of the dispersant is preferably 5% by weight or more in the slurry solids. As the content of the dispersant increases, an improved dispersing effect may be obtained. However, the upper limit of the dispersant content is preferably set to 8% by weight because the content of other components is relatively decreased.

Surfactants

If the surface of the carrier on which the slurry is to be coated is very stable physically and chemically, the slurry is difficult to coat. Therefore, it is desirable for slurry coatings to be able to activate the surface of the carrier. The surfactant serves to activate the surface of the carrier on which the slurry is to be coated. As the surfactant, all commonly used surfactants can be used, but particularly suitable surfactants in the present invention are Photo-Flo200, ethoxylated nonylpheonl, and ethoxylated tree. Ethoxylated tridecyl alcohol, sodium stearate, sodium disopropylnaphtalene sulfonate or dodecyltrimethylammonium chloride, and the like.

In order to obtain the surfactant activation effect by the surfactant, at least 1% by weight of the surfactant solids should be added. However, as the content of the surfactant increases, the content of the other components is relatively decreased, so the upper limit of the content of the surfactant is preferably set to 5% by weight.

Binder

The binder serves to allow the slurry coated on the surface of the carrier to be firmly bonded to the carrier to form a strong bonding layer. The binder may be polyvinyl alcohol, polyvinyl butyral, polymethyl methacrylate, paraffin, wax emulsions or microcrystalline wax. ) May be used.

In order to obtain a sufficient bond strength improving effect, the binder is preferably included at least 17% by weight of the slurry solids. However, when the content of the binder is excessive, other additives may be limited, so the maximum value of the binder is limited to 40% by weight.

Plasticizer

After the slurry is coated on the carrier surface and calcined, there is a high possibility of cracking of the coating layer. The crack causes a decrease in the adhesion strength of the photocatalyst layer and a decrease in the photocatalyst efficiency. The plasticizer is added to suppress cracking after firing. In other words, the crack is caused by the coating layer not absorbing the stress caused by the reduction of the volume of the coating layer by the sintering process, and the plasticizer changes the viscoelasticity of the coating layer, thereby softening the composition. It is to absorb the stress caused by. The plasticizer may include polyethylene glycol, ethylene glycol, ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, glycerol, dibutyl phthalate. (Dibutyl phthalate) or dimethyl phthalate may be used, and in particular, polyethylene glycol 400 (PEG 400) is preferably used.

In order to obtain the effect by the plasticizer, the plasticizer is preferably contained 1% by weight or more in the slurry solids. On the contrary, when the content of the plasticizer is too high, the content of other components is limited, so the upper limit of the content of the plasticizer is limited to 20% by weight.

menstruum

The solvent serves to allow the components of the slurry composition to be uniformly mixed and to have sufficient fluidity to facilitate coating on the carrier surface and to exhibit sufficient bonding strength during the bonding process.

It is preferable to use what has a volatile property as said solvent. More specifically, ethanol, toluene, methanol, butanol, butanol, chloroform, dichloromethane, ethyl acetate, thylacetate, hexane, diethyl ether Diethylehter), acetonitrile, benzene, or a mixture of two or more thereof.

In order for the slurry composition to have sufficient fluidity and to have a strong bond intended in the present invention, the solvent is preferably included in an amount of 100 parts by weight or more relative to 100 parts by weight of the total of other components. However, when the amount of the solvent is excessive, it is preferable that the solvent is included in an amount of 350 parts by weight or less per 100 parts by weight of the slurry solids because the slurry is too thin to take an excessive time to coat the carrier surface with a desired thickness or more. In addition, a more preferable solvent composition for securing the above properties is more preferably 200 to 300 parts by weight.

Therefore, the slurry composition of the present invention is a slurry composition comprising TiO ₂ powder, a dispersant, a surfactant, a binder, a plasticizer and a solvent, specifically, TiO ₂ : 50 to 70% by weight, surfactant: 5 to 8% by weight, Binder: 17 to 40% by weight and plasticizer: consisting of 1 to 20% by weight of the slurry solids and 100 to 350 parts by weight of the solvent contained in 100 parts by weight of the slurry solids.

Hereinafter, a method of manufacturing a TiO ₂ coated contaminant purification material having high catalytic activity by coating a carrier, which is another aspect of the present invention, on a carrier will be described in detail.

Uniform Slurry Preparation

It is preferable that the slurry composition of the present invention described above is uniformly dispersed in a solvent as fine particles. Those skilled in the art to which the present invention pertains may employ conventional mixing methods from the content of the slurry composition under the conditions described above. It will be readily possible to prepare a uniformly mixed slurry composition.

However, one example for preparing a slurry composition in the present invention is as follows. In other words, the slurry composition of the present invention may be obtained by adding a slurry solid to a solvent and then mixing the mixture in a wet manner to obtain a mixture and then dispersing it sufficiently by ultrasonic dispersion. In this case, a mixing method such as ball milling is used for the wet mixing. It is preferable to perform ball milling for 12 hours or more. In addition, it is preferable to perform the ultrasonic dispersion operation for 30 minutes or more.

By the above-described process, it is possible to obtain a coating slurry composition in which each component is finely and uniformly dispersed in a solvent. Of course, it has already been mentioned that various methods other than the above-mentioned methods can be used for slurry mixing.

Slurry coating

Thereafter, the slurry composition is coated on the carrier surface. In this case, as the carrier coated with the slurry, various kinds of carriers, such as foam glass or conventionally used carriers, may be used. However, the micropores do not exist much more than necessary on the surface, and the production is simple and economically advantageous as well as rivers. It is particularly advantageous for concrete carriers that can be used in various blocks of contaminated water because they are easy to use for the protection block or floor.

Dip coating, spin coating, spray coating, powder mixing, surface oxidation, PVD, CVD, etc. can be used for coating. Among them, dip coating is used. It is most preferable at the point that a uniform coating layer can be coated by a more economical method. At this time, the slurry coating is preferably set to 0.05 ~ 0.09g per 6cm ² carrier surface area. If the amount of slurry coating is small, it is difficult to obtain sufficient catalytic activity because the amount of photocatalyst contained in the slurry is insufficient. On the contrary, when the amount of slurry coating is excessive, the surface area in which the photocatalyst is in contact with the contaminants does not increase. It is not desirable because it increases.

dry

The coated slurry is then subjected to a drying process to reduce the moisture content below a certain level. The drying process may be easily applied to anyone having ordinary skill in the art to which the present invention pertains, but one preferred example thereof may include a process made by drying at a temperature of 50 to 70 ° C. for at least 1 hour. have.

Elevated temperature

The slurry coated on the carrier is firmly bonded to the carrier and undergoes a calcination process to obtain purification properties. The firing temperature will be described later, but it is necessary to increase the temperature to the target temperature. At this time, it is important to control the temperature increase rate. That is, when the structural material (carrier + slurry) is raised to an excessively high speed to the target temperature, it is difficult to secure the integrity of the surface because cracking is likely to occur in the coating layer. Therefore, although it is preferable to raise gradually as much as possible, it is possible to raise a temperature up to the speed | rate of 10 degree-C / min in consideration of taking excessive heating time.

Firing

After reaching the target temperature by the elevated temperature, the slurry is maintained on the surface of the carrier by maintaining the temperature at the temperature for a predetermined time. In addition, the organic matter included in the slurry is removed by the sintering process to obtain a better pollutant removal effect. At this time, in order to maintain high photocatalytic properties and to achieve strong bonding, it is important to set the firing temperature and the holding time.

That is, when the firing temperature is low, the organic substances contained in the slurry are not completely removed but remain in the coating layer. In this case, of course, the characteristics of the photocatalyst are deteriorated, and therefore, the organic substances may act as a contaminant, which is not preferable. According to the results of the inventors of the present invention, in order to remove contaminants, the firing temperature needs to be maintained at 300 ° C or higher, more preferably 500 ° C or higher, and most preferably 600 ° C or higher.

On the contrary, when the firing temperature is too high, the organic substance can be completely removed, but there is a fear that the anatase phase contained in the slurry will be phase transformed into a stable rutile phase at a high temperature. When the rutile phase is generated, the photocatalyst efficiency is lowered, which is not preferable. According to the results of the researchers of the present invention, when the firing temperature exceeds 800 ℃ most of the anatase phase is transformed into rutile phase is not preferable, and at a temperature of 700 ~ 800 ℃ some anatase phase is transformed into rutile phase The anatase phase remains stable at temperatures below 700 ° C. Therefore, in order to retain the anatase phase as much as possible, the firing temperature needs to be maintained at 800 ° C or lower, more preferably 700 ° C or lower.

Therefore, the firing temperature of the present invention needs to be maintained at 300 to 800 ° C, preferably 500 to 700 ° C, and most preferably 600 to 700 ° C.

In addition, even if the firing temperature of the slurry is appropriate, if the holding time is not sufficient, it is difficult to obtain sufficient bonding strength and the effect of removing organic substances. Therefore, it is preferable that the said baking time shall be 3 hours or more.

In summary, the method for producing the contaminated water / concrete / TiO ₂ structural material of the present invention includes preparing a slurry composition in which components are finely and uniformly mixed; Coating the slurry composition on a carrier surface; Drying the slurry coated carrier; And raising the dried carrier to a predetermined firing temperature and maintaining the firing temperature for a predetermined time.

The above-described slurry composition of the present invention and a method for producing a TiO ₂ coated contaminant purification material using the same are not limited to contaminated water purification facilities. That is, in the field of removing contaminants contained in the fluid, the slurry of the present invention and the method of coating the same may be used without limiting the subject matter.

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings and preferred embodiments of the present invention. However, the scope of the present invention is not limited by the following examples. This is because the scope of the invention is determined by the appended claims and the matters reasonably inferred therefrom.

(Example)

Preparation of Slurry

The coating slurry was prepared by the composition shown in Table 1. As TiO ₂ used in Table 1, Degussa products (P25 powder) having an average particle size of 21 nm having anatase phase of 70 wt% and rutile phase of 30 wt% were used. In addition, PVB was used as the binder, polyethylene glycol (PEG) or ethylene glycol (EG) was used as the plasticizer, α-terpineol was used as the dispersant, and photo-flo 200 was used as the surfactant. As the solvent, a mixture of ethanol and toluene in a weight ratio of 68:32 was used.

division Slurry Solids (100 parts by weight) menstruum TiO ₂ Binder Plasticizer Dispersant Surfactants PEG EG Comparative Example 1 52.6 parts by weight 42.1 parts by weight - - 5.3 parts by weight - 105 parts by weight Comparative Example 2 49.3 parts by weight 34.5 parts by weight 8.9 parts by weight - 4.9 parts by weight 2.4 parts by weight 123 parts by weight Inventive Example 50 parts by weight 32.5 parts by weight - 7.5 parts by weight 5 parts by weight 5 parts by weight 250 parts by weight

The slurry solids and the solvent of the composition were charged to a teflon pot, and then wet-mixed by ball milling at 100 rpm for 6 hours and then ultrasonically dispersed for 30 minutes to prepare a homogeneous slurry.

TiO on carrier surface ₂ Photocatalyst coating

It was prepared a concrete block as a carrier for carrying the photocatalyst layer, soda lime which is widely used a result of which a porous carrier were compared with _{(70% SiO 2 30% Al} 2 O 3) of foamed glass (GI552, echo sera).

Each slurry prepared by Table 1 was coated on the respective carriers using a dip coating method at 0.07 g per 6 cm ² surface area. After coating, the coated carrier was dried at 60 ° C. for 1 hour at a temperature increase rate of 1 ° C./min, and then heated to a predetermined firing temperature for each structural member at a temperature increase rate of 1 ° C./min. The firing temperature of both structural members was set at 600 ° C. It was maintained at this firing temperature for 5 hours to obtain a structure coated with a photocatalyst.

The porosity of the foam glass used was about 40%, and the porosity of the concrete block was about 18% or less.

Figure 1 shows a scanning electron micrograph observing the surface shape when the slurry prepared by Comparative Example 1, Comparative Example 2 and the invention example was coated on the foam glass carrier. In Figure 1 (a) is a surface shape when the slurry of Comparative Example 1 is coated, (b) is a surface shape when the slurry of Comparative Example 2 is coated, and (c) is a slurry of the invention example It shows the surface shape at the time. As can be seen from Figure 1 (a), it can be seen that in Comparative Example 1 in which no plasticizer was used at all, the surface cracks were deepened. 1 (b) shows that some cracks are formed as a result of Comparative Example 2 in which the composition of the slurry solids does not belong to the range defined by the present invention, and the composition of the solvent does not belong to the most preferred range. You can check it. However, as shown in FIG. 1 (c), as a result of coating the slurry composition suitable for the composition of the slurry composition of the present invention, cracks were hardly generated on the surface thereof, and thus, a good coating layer could be obtained.

In addition, the coating of the slurry having the composition of the present invention on the concrete block was compared whether cracks are generated. 2 shows the surface shape (a) before coating the slurry and the surface shape (b) after coating and baking the slurry. As can be seen in Figure 2 (b) it was possible to obtain a good photocatalyst surface when coated with a slurry having the composition of the invention.

Purification experiment

On the coated concrete block structure having a size of 10 × 10 × 10 mm, a structural member coated with a photocatalytic layer was prepared using a slurry having the composition of the invention example of Table 1, and the glass coated with the photocatalytic layer under the same conditions for comparison. The structural material was prepared.

As contaminated water containing organic matter, 4CP (4-chlorophenol) was dissolved in distilled water to prepare an organic carbon contaminated water having a TOC concentration of 50 ppm, and each structural material prepared in the organic carbon contaminated water was added thereto. Thereafter, after irradiating ultraviolet (UV) light, TOC was measured. While the organic contaminated water was stirred at 100 rpm, the intensity of UV light was adjusted to 160 mW / cm ² and irradiated for 2 hours, and then TOC was measured.

The residual carbon concentration was measured using a TOC analyzer (Shimadzu: TOC-V) to analyze the purification rate of organic contaminated water by photocatalyst.

Figure 3 shows the result after irradiating UV light to the photocatalyst coated structural material, the carbon concentration of 50 ppm of organic carbon contaminated water with time decreases (purification rate) using a foamed glass carrier (a) and concrete block carrier In the case of using (b), each is shown in the figure.

As can be seen in Figure 3, after 2 hours, the carbon concentration in the organic carbon contaminated water was confirmed that 70 ~ 75% is reduced by the conversion to harmless water and carbon dioxide, in particular, the slurry is coated on the concrete block structure carrier It was found that the use of the structural material was higher than the case of using the structural material coated with the slurry on the foam glass carrier. Therefore, it was confirmed that it is more preferable to use a concrete carrier.

River Water Purification Experiment

As a carrier having the same shape as the concrete block carrier used in the contaminated water purification experiment, an experiment was carried out to purify the actual river water using a carrier whose size was increased only to 30 × 30 × 30 mm.

The streams were collected from actual Anam and Dorim streams with TOC concentrations of 15 ppm and 52 ppm, respectively. The TOC was measured after irradiating UV light for 2 hours while stirring the organic contaminated water at 100 rpm.

When the purification rate was measured, the intensity of ultraviolet light was adjusted to 160 mW / cm ² and irradiated for 2 hours.

The residual carbon concentration was measured using a TOC analyzer (Shimadzu: TOC-V) to analyze the purification rate of organic contaminated water by photocatalyst.

Figure 4 shows the results (purification rate) of the carbon concentration of the river water collected from Aamcheon and Dorim stream with time. As can be seen in the figure, the sewage collected from Aamcheon (a) and Dorimcheon (b) shows a high purification rate of 80% or more after 2 hours of treatment.

Analysis of the Effect of Firing Temperature

In order to observe the influence of the calcination temperature, which is a major aspect of the present invention, the TiO ₂ powder (P25) of Degussa, whose ratio of anatase phase and rutile phase is 7: 3, was calcined and observed for the phase change rate. The firing temperature was changed to 300 ° C., 500 ° C., 600 ° C., 700 ° C., 800 ° C. and 900 ° C., respectively, and the trend of phase change with temperature was observed.

The results obtained using the X-ray diffractometer are shown in FIG. 5. In Figure 5, R represents the rutile phase, A represents the anatase phase. As can be seen from FIG. 5, the peak value of the P25 powder before firing was not significantly different until the firing temperature reached 600 ° C., but the peak value of the rutile phase at 700 ° C. was higher than that of the P25 powder before firing. It can be seen that the increase. In addition, it can be seen that at a temperature higher than 800 ° C., the anatase phase is almost lost and the phase changes to the rutile phase.

Therefore, as a baking temperature which does not change a phase, 700 degrees C or less is preferable, and 600 degrees C or less is more preferable.

However, when the TiO ₂ powder containing the anatase phase is included in the slurry composition and coated on the carrier, it is important to adjust the upper limit of the firing temperature so that there is no loss of the anatase phase as described above, but the organic matter contained in the slurry is completely removed. It is also important to keep the temperature as high as possible.

1 and 2 are scanning electron micrographs observing the surface shape when the slurry prepared by Comparative Example 1, Comparative Example 2 and the invention example was coated on the foam glass and the concrete carrier, respectively,

Figure 3 is a graph showing the purification rate results of contaminated water having a 50 ppm TOC according to the type of carrier in the purification experiment,

4 is a graph showing the purification rate result of the TOC of the river water changed over time, and

5 is an X-ray diffraction analysis test result showing how the phase of the TiO ₂ powder changes as the firing temperature is changed.

Claims (6)

50 to 70% by weight of TiO ₂ powder, 5 to 8% by weight of dispersant, 1 to 5% by weight of surfactant, 17 to 40% by weight of binder and 1 to 20% by weight of plasticizer, and 100 to 100 parts by weight of the slurry solids A TiO ₂ slurry comprising 350 parts by weight of a solvent. The method of claim 1, wherein the TiO ₂ powder has a particle size of less than 70%; the content on the anatase TiO ₂ powder as the powder for the photocatalyst is TiO ₂ slurry, characterized in that not more than 50nm. The method of claim 1, wherein the dispersing agent is alpha-terpineol (α-terpineol), the surfactant is Photo-Flo200 (Photo-Flo200), ethoxylated nonylpheonl, ethoxylated Tridecyl alcohol, sodium stearate, sodium disopropylnaphtalene sulfonate and dodecyltrimethylammonium chloride, and the binder is polyvinyl alcohol alcohol, polyvinyl butyral, polymethyl methacrylate, paraffin, wax emulsions and microcrystalline wax, the plasticizer being selected from polyethylene Polyethylene glycol, ethylene glycol, diethylene glycol, trie Triethylene glycol, Tetraethylene glycol, Glycerol, Dibutyl phthalate and Dimethyl phthalate, The solvent is ethanol (Ethanol), Toluene (Toluene) , Methanol, Butanol, Chloroform, Dichloromethane, Ethyl Acetate, Hexane, Diethylehter, Acetonitrile, Benzenene Or a mixture of two or more of these TiO ₂ slurries. 50 to 70% by weight of TiO ₂ powder, 5 to 8% by weight of dispersant, 1 to 5% by weight of surfactant, 17 to 40% by weight of binder and 1 to 20% by weight of plasticizer, and 100 to 100 parts by weight of the slurry solids Preparing a slurry by mixing 350 parts by weight of a solvent; Coating the prepared slurry on a concrete block surface; Drying the slurry coated carrier; And Calcining the dried structural member (carrier + slurry); a method for producing contaminated water / concrete / tiO ₂ structural member. The method of claim 4, wherein the carrier is a method of producing a contaminated water purification concrete / TiO ₂ structural material characterized in that the concrete block. The method of claim 4 or 5, wherein the firing of the dried structural member (carrier + slurry) at a firing temperature after raising the structural member at a rate of 10 ℃ / min or less to a firing temperature of 300 ~ 800 ℃ Method for producing a contaminated water purification concrete / TiO ₂ structural material, characterized in that the process for more than 3 hours.

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