JP3436267B2 - Purification device and photocatalyst cartridge - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention irradiates a photocatalyst with ultraviolet rays from, for example, an ultraviolet ray irradiation lamp to bring the photocatalyst into contact with a treatment fluid such as air or water, and decomposes harmful substances in the treatment fluid by a photocatalytic reaction. The present invention relates to a purifying device for treating harmful substances and a photocatalyst cartridge used therein.

[0002]

2. Description of the Related Art In recent years, as interest in environmental protection has increased, a purification device for treating harmful substances in the atmosphere and water has been required. Under such circumstances, a purifying device using a photocatalyst is receiving attention.

Conventionally, purification of harmful substances using a photocatalyst is
Powdered titanium oxide has been mainly used as a photocatalyst. However, these powdery photocatalysts are difficult to handle, and titanium oxide must be separated from the treated water because titanium oxide is mixed in the water in the purification of water.

In order to solve this problem, it has been practiced to carry a photocatalyst powder on the substrate. For example, JP-A-8
As disclosed in -1036331, a filter obtained by coating titanium oxide on a glass filter has been proposed. Further, as disclosed in, for example, Japanese Patent Application Laid-Open No. 7-227547, there is proposed a photocatalyst cartridge including a photocatalyst carrier in which a photocatalyst is supported on an opening cloth. This photocatalyst carrier has a stacking structure of hollow frustoconical constant mesh openings.

[0005]

However, generally, in the case of carrying the photocatalyst powder by coating, the problem that the photocatalyst powder is mixed into the processed product has not been solved because the photocatalyst powder is likely to fall off due to contact with the processed product. .
Further, in the method of supporting the catalyst on the cloth as in JP-A-7-227547, bridging of the fibers forming the cloth cannot be avoided. As a result, it is difficult for the processing fluid to pass between the fibers, resulting in a large pressure loss. In order to avoid this pressure loss, it is possible to take measures such as defining a certain size or more of openings, or intentionally making holes in the catalyst carrier. JP-A-7-22754
The stacking structure of the hollow frustum-shaped constant-opening cloths described in No. 7 is only the above-mentioned workaround.
In the structure of the purifying device in which the photocatalyst is simply coated on the vessel wall, the contact between the photocatalyst and the object to be treated is very poor, and efficient purifying cannot be expected. In the purification of harmful substances by photocatalysis, it is extremely important to improve the contact between the photocatalyst and the treatment fluid, that is, how large the effective contact area between the photocatalyst and the treatment fluid is. Effective photocatalytic activity cannot be obtained with a structure in which the treatment fluid preferentially passes through the holes in the center or the openings of the cloth, rather than between the individual holes.

[0006]

The inventors of the present invention have already succeeded in developing a photocatalyst fiber by a precursor method by utilizing a natural phenomenon of bleed-out, as shown in Japanese Patent Application No. 2001-171956. According to this method, there is no bridging between fibers, and photocatalyst fibers having a structure in which photocatalyst components such as titania are densely deposited on the surface of each fiber can be obtained. In addition, since the photocatalyst fiber does not use a conventional coating method, the problem that the photocatalyst component on the fiber surface falls off has been solved. The present inventors have examined a method for treating harmful substances and the like using this photocatalyst fiber, and as a result, by using a molded article of the non-woven fabric of this photocatalyst fiber, a stacked structure of conical objects can be formed without making holes. We have succeeded in developing a photocatalyst cartridge with excellent photocatalytic activity by achieving low pressure loss and high contact efficiency with the processing fluid. Since this non-woven fabric has a structure in which fibers are dispersed with a certain amount of voids, the treatment fluid passes through the gaps between the fibers, so that the treatment fluid and the photocatalyst It is characterized by a very large contact area.

That is, the present invention provides a fiber comprising a composite oxide phase of an oxide phase (first phase) mainly containing a silica component and a metal oxide phase (second phase) containing Ti, The treatment fluid is characterized in that a non-woven fabric of silica-based complex oxide fibers having a photocatalytic function is used, in which the proportion of Ti in the metal oxides constituting the two phases increases in a gradient toward the surface layer of the fibers. The present invention relates to a purifying device having excellent contact efficiency with a photocatalyst. Further, the present invention is a fiber comprising a composite oxide phase of an oxide phase (first phase) mainly containing a silica component and a metal oxide phase (second phase) containing Ti, wherein the second phase is The content of Ti in the constituent metal oxides is gradually increasing toward the surface layer of the fiber, and a non-woven fabric of silica-based complex oxide fiber having a photocatalytic function is formed, and the formed product of the non-woven fabric is reacted. The present invention relates to a photocatalyst cartridge having excellent contact efficiency between a processing fluid and a photocatalyst, which is removable in a container.

In the silica-based composite oxide fiber of the present invention, the oxide phase (first phase) having a silica component as a main component means
It may be amorphous or crystalline, and may contain a metal element or a metal oxide capable of forming a solid solution or a eutectic point compound with silica. The metal element (A) capable of forming a solid solution with silica or the metal element (B) whose oxide can form a compound having a specific composition with silica is not particularly limited, but, for example, titanium as (A), Further, as (B), aluminum, zirconium,
Examples thereof include yttrium, lithium, sodium, barium, calcium, boron, zinc, nickel, manganese, magnesium and iron.

This first phase forms the internal phase of the fibers obtained according to the invention and plays an important role in bearing the mechanical properties. The ratio of the first phase to the whole fiber is 9
It is preferably 8 to 40% by weight, and the target second
In order to fully express the function of the phase and also to express the high mechanical characteristics, the existence ratio of the first phase is 50 to 95.
It is preferable to control within the range of weight%.

On the other hand, the metal oxide constituting the second phase plays an important role in exhibiting the photocatalytic function. Ti is mentioned as a metal which comprises a metal oxide phase. This metal oxide may be a simple substance, or a eutectic compound or a substitutional solid solution formed of a specific element. The abundance ratio of the second phase constituting the surface layer portion of this fiber varies depending on the type of oxide, but is 2 to 60
It is preferably in the range of 5 to 50% by weight in order to sufficiently develop its function and also to develop high strength at the same time. The crystal grain size of the second phase metal oxide containing Ti is preferably 15 nm or less, and particularly preferably 10 nm or less.

The proportion of Ti in the metal oxide constituting the second phase increases in a gradient toward the surface of the fiber, and the thickness of the region where the composition gradient is clearly recognized is 5 to 5. It is preferable to control in the range of 500 nm, but it may extend to about 1/3 of the fiber diameter. In the present invention, the “presence ratio” of the first phase and the second phase means the metal oxide forming the first phase and the whole metal oxide forming the second phase,
That is, it means the weight% of the first phase metal oxide and the second phase metal oxide with respect to the entire fiber.

Further, this silica-based composite oxide fiber has a photocatalytic function and at the same time has excellent heat resistance.
For example, the temperature at which 90% or more of the original fiber strength remains after being kept in heated air for 1 hour is 1000 ° C.

Next, the method for producing the silica-based composite oxide fiber of the present invention will be described. In the present invention, the general formula

[Chemical 1] (However, R in the formula represents a hydrogen atom, a lower alkyl group or a phenyl group.) Polycarbosilane having a main chain skeleton and a number average molecular weight of 200 to 10,000 is represented by T
A modified polycarbosilane having a structure modified with an organometallic compound containing i or a mixture of a modified polycarbosilane and an organometallic compound containing Ti is melt-spun, and after infusibilization treatment, fired in air or oxygen. As a result, a silica-based composite oxide fiber can be manufactured.

In the first step, the number average molecular weight used as a starting material for producing a silica-based composite fiber is 1,00.
This is a step of producing 0 to 50,000 modified polycarbosilane. The basic method for producing the modified polycarbosilane is very similar to that in JP-A-56-74126, but in the present invention, it is necessary to carefully control the bonding state of the functional groups described therein. is there. This is outlined below.

The modified polycarbosilane which is the starting material is
Mainly general formula

[Chemical 2] (However, R in the formula represents a hydrogen atom, a lower alkyl group or a phenyl group.) A polycarbosilane having a main skeleton represented by a number average molecular weight of 200 to 10,000 and a general formula, M (OR ') n or MR''m (M is at least T
i and R'are alkyl or phenyl groups having 1 to 20 carbon atoms, R "is acetylacetonate, m and n
Is derived from a Ti-containing organometallic compound (hereinafter simply referred to as an organometallic compound) having a basic structure of an integer greater than 1.

Here, in order to produce the fiber having the graded composition of the present invention, it is necessary to select a slow reaction condition in which only a part of the above-mentioned organometallic compound forms a bond with polycarbosilane. Therefore, 280 ° C or lower, preferably 25
It is necessary to react in an inert gas at a temperature of 0 ° C or lower. Under this reaction condition, even if the organometallic compound is reacted with polycarbosilane, it is bonded (that is, pendantly bonded) as a monofunctional polymer, and a large increase in molecular weight does not occur. The modified polycarbosilane in which the organometallic compound is partially bonded plays an important role in improving the compatibility between the polycarbosilane and the organometallic compound.

When a large number of bifunctional or higher functional groups are bonded, a polycarbosilane bridge structure is formed and a marked increase in the molecular weight is observed. In this case, a rapid heat generation and a rise in melt viscosity occur during the reaction. On the other hand, when only the above-mentioned monofunctional compound is reacted and the unreacted organometallic compound remains, a decrease in melt viscosity is observed.

In the present invention, it is desirable to select conditions under which unreacted organometallic compound is intentionally left. In the present invention, the above modified polycarbosilane and an unreacted organometallic compound or an organometallic compound in the range of about 2-3 trimers are mainly used as a starting material, but the modified polycarbosilane alone has an extremely low molecular weight. When the modified polycarbosilane component of 1 is contained, it can be similarly used as the starting material of the present invention.

In the second step, the modified polycarbosilane obtained in the first step or a mixture of the modified polycarbosilane and a low molecular weight organometallic compound (hereinafter referred to as a precursor polymer) is melted to prepare a spinning solution. In the production, in some cases, this is filtered to remove substances harmful to the spinning such as microgels and impurities, and this is spun by a commonly used synthetic fiber spinning device. The temperature of the spinning dope during spinning depends on the softening temperature of the modified polycarbosilane as the raw material, but a temperature range of 50 to 200 ° C. is advantageous. In the above spinning device, a humidification heating cylinder may be provided below the nozzle, if necessary. The fiber diameter is adjusted by changing the discharge amount from the nozzle and the winding speed of a high-speed winding device installed below the spinning machine.

In the second step, in addition to the melt spinning, the precursor polymer obtained in the first step is treated with, for example, benzene,
Toluene, xylene or other precursor polymer is dissolved in a solvent capable of melting to prepare a spinning dope,
In some cases, this is filtered to remove harmful substances such as macrogels and impurities during spinning, and then the spinning solution is spun by a dry spinning method using a synthetic fiber spinning device that is usually used, and the winding speed is controlled to achieve the purpose. The fiber which does can be obtained.

In these spinning steps, if necessary,
A spinning cylinder is attached to the spinning device, and the atmosphere in the cylinder is a mixed atmosphere with at least one gas of the solvents, or air, an inert gas, hot air, a heat inert gas,
By setting the atmosphere of steam, ammonia gas, hydrocarbon gas, and organosilicon compound gas, the solidification of the fibers in the spinning cylinder can be controlled.

In the third step, the spun fiber is infusibilized by preheating the spun fiber under an action of tension or no tension in an oxidizing atmosphere. This step is performed for the purpose of preventing the fibers from being melted and adhering to the adjacent fibers at the time of firing in the subsequent step. The treatment temperature and the treatment time differ depending on the composition and are not particularly specified, but generally, a treatment condition of several hours to 30 hours is selected within the range of 50 to 400 ° C. Also, in the oxidizing atmosphere,
It may contain water, nitrogen oxides, ozone, etc. that enhance the oxidizing power of the spun fiber, and the oxygen partial pressure may be intentionally changed.

By the way, depending on the proportion of low molecular weight substances contained in the raw material, the softening temperature of the spun fiber may be lower than 50 ° C. In that case, oxidation of the fiber surface should be carried out at a temperature lower than the above treatment temperature in advance. In some cases, a process for promoting It is considered that, in the third step and the second step, bleeding out of the low molecular weight compound contained in the raw material to the fiber surface progresses to form an underlayer having a desired gradient composition. There is.

In the fourth step, the infusibilized fiber is fired under tension or no tension in an oxidizing atmosphere in a temperature range of 500 to 1800 ° C. to obtain a desired oxide mainly composed of a silica component. Phase (first phase) and a metal oxide phase containing Ti (second phase), which is a composite oxide phase, and the proportion of Ti in the metal oxide forming the second phase gradually increases toward the surface layer. Increased silica-based complex oxide fibers are obtained.
In this step, the organic component contained in the infusibilized fiber is basically oxidized, but depending on the selected conditions,
It may remain in the fiber as carbon or carbide. Even in such a state, if the intended function is not hindered, it is used as it is, but if it is hindered, further oxidation treatment is performed. At that time, the temperature and the treatment time must be selected so that the intended graded composition and crystal structure do not cause any problems.

In the present invention, the silica-based composite oxide fiber having a photocatalytic function obtained by the above production method is made into a short fiber and then needle punched to obtain a nonwoven fabric. The basis weight and thickness of the non-woven fabric are not particularly limited, but usually, the basis weight is 50 to 500 g / m ² , and the thickness is 0.5 to
Although the thickness of 20 mm is used, this non-woven fabric may be laminated so as to have a required thickness if necessary.

The non-woven fabric of the silica-based composite oxide fiber of the present invention uses the melt blow method to melt the precursor polymer and discharges the melt from the spinning nozzle.
A heated nitrogen gas is spouted from the periphery of the spinning nozzle to perform spinning, and the nonwoven fabric is formed by collecting the spun fibers in a receiver arranged below the spinning nozzle. Then, the nonwoven fabric is infusibilized and then oxidized. It can be manufactured by firing in an atmosphere.

The diameter of the spinning nozzle is usually 100 to 500 μm.
The thing of about m is used. Nitrogen gas ejection speed is 30-30
It is about 0 m / s, and finer fibers can be obtained as the speed increases. The heating temperature of the nitrogen gas is not particularly limited as long as the desired spun fiber can be obtained, but the nitrogen gas heated to about 500 ° C. is usually ejected. Conventionally, in a general melt blow method, air is used as a jet gas,
Nitrogen must be used to spin the precursor polymer. By using nitrogen as the jet gas, stable spinning can be performed.

When the precursor polymer is spun and the spun fiber is collected in a receiver arranged below the spinning nozzle,
It is preferable to use a suction-capable receiver while suctioning from the lower side of the receiver. By suctioning, the fibers are effectively entangled and a high-strength nonwoven fabric is obtained. The suction speed is preferably in the range of 2 to 10 m / s.

Next, the non-woven fabric of the present invention is obtained by subjecting the obtained non-woven fabric to infusibilization treatment and firing similar to those in the above-mentioned melt spinning. The silica-based composite oxide fiber produced by the melt-blowing method has an average fiber diameter of 1 to 20 μm, preferably 1 to 8
μm, and more preferably 2 to 6 μm, which is thinner than the fiber produced by the melt spinning method. As a result, the surface area of the fiber can be increased and the catalytic activity is increased. Further, the nonwoven fabric produced by the melt blow method has longer fibers than the nonwoven fabric produced by the melt spinning method and having a length of about 40 to 50 μm by the needle punch method. As a result, the non-woven fabric has high strength (tensile strength of 2 N or more) and has sufficient pleating workability when processed into a filter or the like.

Next, the non-woven fabric obtained above is molded into a desired shape to obtain a photocatalyst cartridge that can be attached to and detached from the reaction container. The forming method is not particularly limited, but a specific shape can be formed using, for example, a stainless steel wire net as a support material.

In the photocatalyst cartridge of the present invention, as shown in FIG. 1, the molded article of the non-woven fabric has a conical shape and can be arranged in multiple stages in the reaction vessel at a certain interval along the flow of the processing fluid. . It is possible to further increase the contact area between the photocatalyst and the treatment fluid by arranging the photocatalyst in multiple stages, and by making the photocatalyst into a conical shape,
It is possible to effectively irradiate the photocatalyst with the ultraviolet light necessary for the photocatalytic reaction.

Further, as shown in FIG. 2, the molded article of the non-woven fabric is formed into a hollow truncated cone shape and arranged in multiple stages,
It is also possible to arrange an ultraviolet lamp in the center.
Further, in this photocatalyst cartridge, it is possible to facilitate the attachment / detachment to / from the reaction container by forming a multi-stage molded product into a connection structure using a frame body or the like.

[0033]

EXAMPLES The present invention will be described below with reference to examples. Reference Example 1 2.5 liters of anhydrous toluene and 400 g of sodium metal were placed in a 5 liter three-necked flask and heated to the boiling point of toluene under a nitrogen gas stream, and dimethyldichlorosilane 1 was added.
L was added dropwise over 1 hour. After completion of dropping, the mixture was heated under reflux for 10 hours to generate a precipitate. This precipitate is filtered,
First, it was washed with methanol and then with water to obtain 420 g of white powdery polydimethylsilane. 250 g of polydimethylsilane was charged into a three-necked flask equipped with a water-cooled reflux device, and heated and reacted at 420 ° C. for 30 hours under a nitrogen stream to obtain polycarbosilane having a number average molecular weight of 1200.

Example 1 Polycarbosilane 16 synthesized by the method of Reference Example 1
To 100 g of toluene, 100 g of toluene and 64 g of tetrabutoxytitanium were added, preheated at 100 ° C. for 1 hour, then slowly heated to 150 ° C., toluene was distilled off, the reaction was continued for 5 hours, and further heated to 250 ° C. And reacted for 5 hours to synthesize a modified polycarbosilane. To this modified polycarbosilane, 5 g of tetrabutoxytitanium was intentionally added for the purpose of allowing a low-molecular weight organometallic compound to coexist to obtain a mixture of the modified polycarbosilane and the low-molecular weight organometallic compound.

A mixture of this modified polycarbosilane and a low molecular weight organometallic compound was dissolved in toluene and charged into a glass spinning device, and the interior was sufficiently replaced with nitrogen, and then the temperature was raised to distill off the toluene. Melt spinning was performed at 180 ° C. The spun fiber was heated in air stepwise to 150 ° C. to make it infusible and then fired in air at 1200 ° C. for 1 hour to obtain a titania / silica fiber.

The obtained fiber (average diameter: 13 μm) is
As a result of X-ray diffraction, it consisted of amorphous silica and titania of anatase, and the Ti / Si (molar ratio) of the whole fiber was 0.17. Moreover, when the distribution state of constituent atoms by EPMA was examined, it was found that T
i / Si (molar ratio) = 0.87, 3 to 4 μm from the outermost periphery
In the region of Ti / Si (molar ratio) = 0.15, T in the center
It was confirmed that i / Si (molar ratio) = 0.04 and the composition was graded such that titanium increased toward the surface. The tensile strength of the fiber was 1.5 GPa, which was significantly higher than that of the anatase-type titania / silica fiber obtained by the conventionally known sol-gel method.

The titania / silica fiber obtained was made to have a length of 50.
After making the fiber into mm short fibers, needle punching was performed to obtain a titania / silica fiber felt having a basis weight of 100 g / m ² and a thickness of 1 mm.

This titania / silica fiber felt 1
0 sheets were laminated to have a thickness of about 10 mm, and this was molded into a conical shape with a diameter of 130 mm and a height of 65 mm using a stainless wire mesh (wire diameter: 1 mm, 3 mesh) as a support material to obtain a photocatalyst cartridge (1). . This was arranged in multiple stages in the reaction vessel (2) as shown in FIG. In FIG. 1, the size of the reaction container is not particularly limited,
In this embodiment, the inner diameter is 130 mm and the height is 600 mm.
The material of this reaction container is preferably a substance that transmits ultraviolet light and does not elute the components in the processing fluid. In this example, transparent quartz was used. Four 40 W ultraviolet lamps (3) are arranged outside the reaction vessel. Water containing 500 ppb of trichlorethylene was caused to flow from the reaction vessel inlet (4) at a flow rate of 0.3 m / s while irradiating with ultraviolet rays.
As a result of sampling water at the outlet of the reaction vessel (5) and analyzing the trichlorethylene concentration by gas chromatography, it was 5 ppb or less.

Further, while irradiating with ultraviolet rays, air containing 50 ppm of acetaldehyde was caused to flow from the reaction vessel inlet (4) at a flow rate of 3 m / s. As a result of sampling the air at the outlet (5) of the reaction vessel and analyzing the acetaldehyde concentration by gas chromatography, it was 1 ppm or less.

Example 2 Ten pieces of the titania / silica fiber felt obtained in Example 1 were laminated to have a thickness of about 10 mm, and this was used as a support material with a stainless steel wire mesh (wire diameter 1 mm, 3 mesh) as a support material. 180mm, height 90mm, diameter 30 in the center
A photocatalyst cartridge (6) was obtained by molding into a hollow truncated cone shape with a hole of mm. This was arranged in multiple stages in the reaction vessel (7) as shown in FIG. In FIG. 2, the dimensions of the reaction vessel are not particularly limited, but in this example, the inner diameter was 180 mm and the height was 600 mm. The material of the reaction vessel is preferably a substance that does not elute the components in the processing fluid. In this example, stainless steel was used. One 60 W ultraviolet lamp (8) is arranged in the center of this reaction vessel. This UV lamp (8) transmits UV light,
And diameter 3 made of a substance that does not elute components in the processing fluid
It is inserted in a 0 mm protective tube (9). In this example, a protective tube made of transparent quartz was used. The photocatalyst cartridge (6) is in close contact with the inner surface of the reaction container (7) and the protective tube (9). While irradiating with ultraviolet rays, water containing 1000 cells / ml of Escherichia coli was caused to flow from the reaction vessel inlet (10) at a flow rate of 0.3 m / s. Reaction vessel outlet (1
As a result of sampling the water of 1) and measuring the number of E. coli,
No E. coli was found.

Comparative Example 1 TiO ₂ (titania) as a photocatalyst component was supported on a glass cloth having an opening of 0.5 mm, a pitch of 2 mm and a thickness of 0.5 mm by the thin film forming method described in JP-A-5-97280.
The supported amount was 40 g / m ² .

Using this glass cloth carrying the titania, as in the case of Example 1, a conical photocatalyst cartridge having a diameter of 130 mm and a height of 65 mm was prepared as shown in FIG.
The apparatus was installed in multiple stages in the same apparatus as in Example 1 and the evaluation of purification of trichlorethylene in water and acetaldehyde in air was performed in the same manner as in Example 1. However, in any of the evaluations, the pressure loss of the photocatalyst was large, and the evaluation could not be performed.

Comparative Example 2 In order to reduce the pressure loss of the photocatalyst, a hole having a diameter of 30 mm was opened in the central portion of the conical photocatalyst cartridge obtained in Comparative Example 1, and the multi-stage installation was performed as in FIG. In the same manner as in 1, purification evaluation of trichlorethylene in water and acetaldehyde in air was performed. Although the pressure loss was reduced as compared with the case of Comparative Example 1, the trichloroethylene concentration in water was 200 ppb at the outlet concentration for the device inlet concentration of 500 ppb, and the acetaldehyde concentration in the air was at 50 ppm for the inlet concentration. The outlet concentration was 20 ppm, which was significantly lower than the purification capacity of Example 1.

The present inventors analyzed the flow of the fluid in the reaction vessel by using the fluid analysis software STAR CD in order to investigate such a difference in the purifying ability. The result is shown in Figure 3.
Shown in. That is, the photocatalyst proposed in the present invention has no bridging between fibers, and uses a photocatalyst fiber having a structure in which photocatalyst components such as titania are densely deposited on the surface of each fiber, and has a felt shape. I use what I made. This felt-shaped material has a structure in which fibers are dispersed with some voids,
Since the treatment fluid passes through the gaps between the fibers one by one, the pressure loss is small, and the contact area between the treatment fluid and the photocatalyst can be made very large. As a result, a very high purification capacity is obtained. On the other hand, since the structure in which the photocatalyst is supported on the glass cloth has a large pressure loss, it is unavoidable to form the structure in which a hole is partially formed as in Comparative Example 2. However, in the case of such a structure, since the treatment fluid flows on the surface of the glass cloth rather than on the inside of the glass cloth, the contact efficiency between the photocatalyst and the treatment fluid is extremely poor. Therefore, it is considered that the purification capacity is low.

Example 3 Polycarbosilane 16 synthesized by the method of Reference Example 1
To 100 g of toluene, 100 g of toluene and 64 g of tetrabutoxytitanium were added, preheated at 100 ° C. for 1 hour, then slowly heated to 150 ° C., toluene was distilled off, the reaction was continued for 5 hours, and further heated to 250 ° C. And reacted for 5 hours to synthesize a modified polycarbosilane. To this modified polycarbosilane, 5 g of tetrabutoxytitanium was intentionally added for the purpose of allowing a low-molecular weight organometallic compound to coexist to obtain a mixture of the modified polycarbosilane and the low-molecular weight organometallic compound.

A mixture of this modified polycarbosilane and a low molecular weight organometallic compound was dissolved in toluene and charged into a glass spinning device, and the inside was sufficiently replaced with nitrogen, and then the temperature was raised to distill off the toluene. , Melted at 180 ° C., discharged from a spinning nozzle having a diameter of 300 μm,
Nitrogen gas heated to 500 ° C. was spouted from the periphery of the spinning nozzle at a speed of about 50 m / s for spinning, and a receiver arranged at the lower part of the spinning nozzle suctioned from the lower side of the receiver at about 5 m / s. The felt was formed by collecting spun fibers while aspirating at a speed. This felt was heated to 150 ° C. in air in stages to make it infusible, and then fired in air at 1200 ° C. for 1 hour to obtain a titania / silica fiber felt having a basis weight of 100 g / m ² and a thickness of 1 mm. Obtained. The diameter of this titania / silica fiber is 5 μm,
The titania / silica fiber obtained by melt spinning in Example 1 was thinner than 8 μm, and therefore the specific surface area was doubled. Also, this felt is 5 cm wide and 20 cm long.
When the tensile strength was 5 N when the test piece of was cut out and the tensile test was done in the length direction.

As in the case of Example 1, this titania /
10 sheets of felt made of silica fiber are laminated to have a thickness of about 10 mm, and this is 130 mm in diameter and 65 in height with stainless steel wire mesh (wire diameter 1 mm, 3 mesh) as a support material.
Photocatalyst cartridge (1) molded into mm-shaped cone
, And arranged in multiple stages in the reaction vessel (2) shown in FIG. While irradiating the reaction container with ultraviolet rays, water containing 500 ppb of trichlorethylene was caused to flow from the reaction container inlet (4) at a flow rate of 0.3 m / s. As a result of sampling the water at the outlet (5) of the reaction container and analyzing the trichlorethylene concentration by gas chromatography, it was 1 ppb or less.

While irradiating with ultraviolet rays, air containing 50 ppm of acetaldehyde was caused to flow from the inlet (4) of the reaction vessel at a flow rate of 3 m / s. As a result of sampling the air at the outlet (5) of the reaction container and analyzing the acetaldehyde concentration by gas chromatography, it was 100 ppb or less.

[Brief description of drawings]

FIG. 1 is a schematic diagram of a purifying device in which a photocatalyst cartridge of Example 1 is incorporated.

FIG. 2 is a schematic view of a purifying device incorporating the photocatalyst cartridge of the second embodiment.

FIG. 3 is a diagram showing an analysis result of a flow of a processing fluid in a reaction container.

[Explanation of symbols]

1 Photocatalyst cartridge 2 reaction vessels 3 UV lamp 4 Reaction vessel inlet 5 Reaction vessel outlet 6 Photocatalyst cartridge 7 Reaction vessel 8 UV lamp 9 Protection tube 10 Reaction vessel inlet 11 Reaction vessel outlet

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI C02F 1/72 101 A61L 9/00 C // A61L 9/00 9/20 9/20 B01D 53/36 J (56) References JP-A-11-269725 (JP, A) JP-A-7-227547 (JP, A) JP-A-10-141044 (JP, A) JP-A-2000-86497 (JP, A) (58) Fields investigated ( Int.Cl. ⁷ , DB name) B01J 21/00-38/74 B01D 53/86 B01D 53/94 JISST file (JOIS)

Claims (7)

(57) [Claims] 1. An oxide phase mainly comprising a silica component (first
Phase) and a metal oxide phase (second phase) containing Ti, which is a composite oxide phase, and is a metal oxide that constitutes the second phase.
The Ti content of the material gradually increases toward the surface layer of the fiber.
In general, a purification device excellent in contact efficiency between a processing fluid and a photocatalyst is characterized by using a non-woven fabric of silica-based composite oxide fiber having a photocatalytic function. 2. An oxide phase mainly comprising a silica component (first
Phase) and a metal oxide phase (second phase) containing Ti, which is a composite oxide phase, and is a metal oxide that constitutes the second phase.
The Ti content of the material gradually increases toward the surface layer of the fiber.
In addition, a non-woven fabric of silica-based complex oxide fiber having a photocatalytic function is formed, and the formed product of the non-woven fabric is detachable in the reaction vessel, which is excellent in contact efficiency between the processing fluid and the photocatalyst. Photocatalyst cartridge. 3. The photocatalyst cartridge according to claim 2, wherein the molded article of the non-woven fabric has a conical shape, and the conical molded articles are arranged in multiple stages. 4. The non-woven fabric molded article is in the shape of a hollow truncated cone, and the hollow truncated cone shaped articles are arranged in multiple stages,
The photocatalyst cartridge according to claim 2, wherein an ultraviolet lamp can be arranged in the central portion. 5. The abundance ratio of the first phase to the whole fiber is 98.
The photocatalyst cartridge according to claim 2, wherein the content of the second phase is 2 to 60% by weight. 6. The photocatalyst cartridge according to claim 2, wherein the gradient of the abundance of Ti in the metal oxide forming the second phase is present at a depth of 5 to 500 nm from the fiber surface. 7. The photocatalyst cartridge according to claim 2, wherein the second-phase metal oxide is titania, and the crystal grain size thereof is 15 nm or less.