JP2005224654A - Channel water treatment device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a waste water treatment device for decomposing fungi such as algae and a trace amount of organic matter such as endocrine disrupting chemical substance where a trace amount of organic matter is effectively adsorbed and decomposed, and further, fungi such as algae can be simultaneously suppressed. <P>SOLUTION: In the channel water treatment device, photocatalyst-supporting active carbon is installed in the surface of a rotor so as to be effectively brought into contact with organic matter in waste water and so as to feed the organic matter to the surface of the photocatalyst-supporting active carbon having high activity, thus the organic matter is adsorbed/decomposed. The function of the active carbon adsorbent material is recovered by the photocatalyst, the function can be maintained over a long period, and the effect can be exhibited even in waste water with a relatively large load. Further, since the photocatalyst-supporting active carbon is rotated by the dynamic pressure or water head of a channel, a rotary driving apparatus is not required, and light energy from visible light and an artificial light source can be effectively absorbed. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a water treatment apparatus in which a photocatalyst is supported on an activated carbon adsorbent.

  Conventionally, separation techniques such as filtration and centrifugation are mainly used as techniques for treating a substance to be treated in waste water. On the other hand, many elemental technologies have been proposed as decomposition technologies.

In recent years, a trace amount of harmful organic substances in wastewater has been discharged into the environment and has become a problem. Currently, photocatalysts have been proposed as elemental technologies for decomposing them. However, because they operate in the ultraviolet region, only a part of the energy of the light source is used, the efficiency is low, and the cost is high because of the presence of a stirring device. Effective technology has not been put into practical use.
JP2002-282669

  For example, as a technique for treating fungi in wastewater using a vibration stirring blade, there is a disturbance of a vibration sterilization device for sterilization. This method is equipped with a light source and sterilized by a combination with a vibration stirring device in which a photocatalyst is attached to the blade. It is an object. When this apparatus is used as a germicidal sterilization apparatus, the treatment is not sufficient in drainage with a load of 1 ppm or more, and there are disadvantages that the light source and the dynamic and initial costs required for stirring are expensive.

  The problem of the present invention is that, in a wastewater treatment apparatus that decomposes trace organic substances such as fungi such as algae and endocrine disrupting chemical substances, the photocatalyst rotates due to the dynamic pressure of the water channel or the head pressure of the water, and can effectively contact the organic matter in the wastewater. The organic matter is adsorbed and decomposed by being sent to the surface of the activated carbon supporting the highly active photocatalyst, and the decomposed substance does not accumulate or adhere to the surface by leaving the activated carbon surface quickly. Because the function of the activated carbon adsorbent is restored by the photocatalyst, the function can be maintained for a long time, and the effect can be exerted even in drainage with a relatively large load of 5 ppm to 10 ppm, and the photocatalyst-supported activated carbon rotates due to the dynamic pressure of the water channel or the head pressure. An aqueduct water treatment device characterized in that it can effectively absorb light energy from visible light and an artificial light source without requiring a rotary drive device.

  Means for solving the problems according to the present invention will be described below.

  Organic matter with a highly active photocatalyst using activated carbon fibers supported on a reinforced frame that is arranged in multiple stages in the water channel and rotated by the head pressure difference and / or dynamic pressure of running water and a light source that lights at night or when light energy is insufficient In an inexpensive water treatment system where light energy is adsorbed during the time when light energy is not applied and decomposition is promoted during the time when light energy is applied, the energy due to falling water in the water channel weir or the dynamic pressure due to the flow of the water channel is reduced. Can be rotated using. A plurality of reinforced plate-like blades are attached, and a titanium oxide solution is applied to the activated carbon fibers on the blades and baked. A highly active photocatalyst-supported activated carbon fiber cloth that operates under visible light is attached to the upper part of the rotating body. A light source that excites the photocatalyst is arranged, and the light source is turned off when the solar energy necessary to excite the photocatalyst is present, and is turned on at night or when the solar energy is insufficient, and is attached to the rotating body. When the activated carbon fiber cloth is moved to a position where it can move to a position where it can absorb enough light energy when it enters water or in the shaded area where light does not reach, the organic substance is oxidized by the redox action of the active oxygen species on the surface of the photocatalyst. Are decomposed, and the decomposition is sequentially promoted and made harmless by the rotating bodies installed in multiple stages. The light source is preferably a high pressure mercury lamp or the like having a wavelength of 350 nm or more, and preferably emits a lot of energy in the range of 350 nm to 450 nm. In particular, a light emitting diode that can specify a wavelength with little heat loss is desirable.

  For preparation of the photocatalyst, the activated carbon fiber cloth carrier is immersed in the titanium oxide solution for 5 seconds to 1 hour. A titanium oxide solution manufactured by Sustainable Technology was used. Thereafter, it is naturally dried and fired in the range of 900 ° C. to 1300 ° C. for 4.5 hours to 21 hours under vacuum to form a titanium oxide thin film on the surface. The temperature increase / decrease rate is in the range of 50 ° C./hour to 200 ° C./hour, and it is desirable to hold the temperature for 5 minutes to 3 hours when the maximum temperature is reached. With this manufacturing method, the titanium dioxide crystal becomes rutile and can be easily supported on fibrous activated carbon, and the active site of the crystal structure, which is said to have oxygen defects caused by firing in vacuum, is activated in the visible light range. To do.

The activated carbon fiber carrier of the present invention carbonizes a fibrous activated carbon raw material knitted fabric in an inert atmosphere at a temperature of 350 ° C. or higher and 1300 ° C. or lower, and then reacts with carbon at a temperature of 500 ° C. or higher and 1300 ° C. or lower. Those activated and carbonized in an active atmosphere containing the above can be suitably used. In some cases, carbonization and activation can be performed simultaneously by controlling the atmospheric conditions. In addition, since the weight yield will be remarkably reduced if the maximum reached temperature in activation treatment, that is, activated carbonization, is 1300 ° C. or higher, it is preferable to set the maximum reaching temperature to 1300 ° C. or lower. Thereby, a knitted fibrous activated carbon having a specific surface area of 1000 to 3000 m ² / g is obtained. The adsorption performance of the activated carbon knitted fabric is 30 g / m ² or more (at 25 ° C., 1/10 dilution condition), preferably 40 g / m ^{2 in} terms of the toluene adsorption performance described in paragraph 5.7 of JlSK1477 “Fibrous activated carbon test method”. m is required ² or more. If below this adsorption amount, the amount of supported catalyst is insufficient, although the specific surface area by the .BET method can not be sufficiently exhibited performance correlates with toluene adsorption performance, 1000~3000h / g If it is 1000 m ² / g or less, the supported amount of the catalyst is insufficient, and the performance cannot be sufficiently exhibited. If it is 3000 m ² / g or more, the specific gravity of the fiber is remarkably lowered, and the shape of the knitted fabric is reduced. I can't hold it.

As a surface modification method for hydrophilic activated carbon having hydrophilicity suitable for the present invention, for example, a weight yield in the range of 65 to 99% in an oxygen atmosphere having an oxygen partial pressure of 1 × 10 ⁻² torr or more. We carry out to become. The treatment temperature is preferably 300 to 700 ° C. At low temperatures, the reactivity of the carbon material to be treated falls, so that the oxidation effect cannot be obtained. Further, at high temperatures, hydrophilic groups such as hydroxyl groups and carboxyl groups cannot be imparted to the surface. The same effect can be obtained by wet treatment using strong acid or electro-oxidation, or plasma treatment. As a result, a hydrophilic fibrous activated carbon having a total acidic group amount of 0.1 meq / g or more can be obtained, and is preferably 6 meq / g or less. Preferably, the total acidic group amount is in the range of 0.2 meq / g to 3 meq / g.

  As described above, according to the present invention, trace organic substances can be effectively adsorbed and decomposed under visible light, fungi such as algae can be suppressed, and the water environment can be improved at low cost.

  An embodiment of the present invention will be described below with reference to FIG. A photocatalyst-supporting fibrous activated carbon water treatment device 1 attached to a plurality of reinforcing frames installed in the water channel 4 as a device for decomposing organic substances and fungi such as algae having a concentration of 10 mg / L or less diffused in the flow channel 4 The shaft 3 is rotated around the center by the head pressure of the drainage overflowing from the weir 2 and the dynamic pressure of the water flowing through the flow path. A light source 3 that generates ultraviolet rays is arranged on the upper part of the photocatalyst-supporting fibrous activated carbon water treatment device 1, and the light source is turned off during the time when the photocatalyst is operated with visible light, and automatically when the photocatalyst is insufficient at night and when the photocatalyst operates. It has a lighting device 6, and trace organic substances in the waste water passing through the water channel are adsorbed by the activated carbon pores and simultaneously oxidized and reduced by the hydroxyl radicals and active oxygen species generated on the photocatalyst by the supported photocatalyst. And discharged to the environment.

[Example 1]
In the apparatus shown in FIG. 1, 500 mL of methylene blue solution having a concentration of 10 ppm is put into a channel having a width of 5 cm, and a photocatalyst in which rutile titanium oxide is supported on a fibrous activated carbon knitted fabric having total acid group amounts of 1.0 meq / g and 1300 m ² / g. As a result of attaching a total surface area of about 240 cm ² and circulating under visible light for 2 hours, the concentration of methylene blue was reduced to 1/15 (6.7%).
On the other hand, as a result of testing with a fibrous activated carbon knitted fabric having the same surface area that does not carry a photocatalyst in the same apparatus, the methylene blue concentration decreased to 1/4 (25%) after 2 hours.
[Example 2]
In the apparatus of FIG. 1, the supernatant of a goldfish tank in which algae was generated was put into a channel having a width of 5 cm, and a fibrous activated carbon knitted photocatalyst similar to Example 1 was attached to a total surface area of about 240 cm ² and circulated for 2 weeks. Did not occur. On the other hand, in the case of a test using the same surface area fibrous activated carbon knitted fabric that does not carry a photocatalyst in the same apparatus, generation of algae was observed after 3 days.

  As described above, according to the present invention, trace organic substances can be effectively adsorbed and decomposed under visible light, fungi such as algae can be suppressed, the water environment can be improved at low cost, and industrially effective. Is available.

The top view of the apparatus which processes the trace amount organic substance and algae which were spread | diffused in the liquid.

The schematic diagram of the reinforcement frame installed in a waterway.

The side view of the apparatus which processes the trace amount organic substance and algae which were spread | diffused in the liquid.

Explanation of symbols

1: Photocatalyst carrying fibrous activated carbon 2: Weir 3: Light source 4: Water channel 5: Shaft 6: Automatic lighting device

Claims (4)

  An aqueduct water treatment apparatus in which a photocatalyst using activated carbon fibers as a carrier and a structure that can be rotated by a head pressure difference and / or dynamic pressure of running water are arranged in multiple stages in a water channel.   2. The waterway water treatment apparatus according to claim 1, wherein the photocatalyst carries rutile titanium oxide on fibrous activated carbon having hydrophilicity.   The channel water treatment apparatus according to claim 1, wherein the fibrous activated carbon has a total acidic group amount of 0.1 meq / g or more. 4. The water channel water treatment according to claim 1, wherein the fibrous activated carbon fiber carrier has a toluene adsorption performance of 30 g / m ² or more and a specific surface area by the BET method of 1000 to 3000 m ² / g. apparatus.

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