JPH04141294A - Water and wastewater photochemical treating method - Google Patents

Abstract

PURPOSE:To disperse semiconductor fine particles in water to be treated to carry out efficient optical treatment of the water to be treated by bundling fibers to whose surface semiconductor fine particles adhere and inserting the bundled fibers into a tank 9f the water to be treated and irradiating the treatment tank with ultraviolet rays. CONSTITUTION:Ultraviolet-rays emitted from a high pressure mercury lamp 3 are projected to water to be treated which is sent to a treatment tank 1 through an inlet 1a. Meanwhile, sunbeams are converged by a converging lens 7 and then led to glass fibers 5a through the tip parts of a glass fiber bundle 5 to irradiate the treatment tank 1 of the water or waste water with ultraviolet rays through the tip parts or the side parts of the glass fibers 5a. Already used bath water sent to the treatment tank 1 is treated optically in the presence of semiconductor fine particles 4 of titanium dioxide by applying ultraviolet-rays and sunbeams to the treatment tank 1. As a result, the bath water is cleaned to the level able to be re-used. For this example, sunbeams are directed to the converging lens 7, ultraviolet-rays may be projected.

Description

[Detailed Description of the Invention] (Industrial Application Field) This invention relates to a simple optical treatment method for industrial wastewater using semiconductor fine particles such as titanium dioxide as a catalyst.
For example, the present invention relates to a method suitable for treating trichloroethylene, trichloroethane, cyanide ions, dichromate ions, hard-to-decompose halogen organic compounds, BOD, TOC, and the like.

(Prior Art) Conventionally, chemical treatments such as chlorine have been used to sterilize water, but there is a tendency for chemical sterilization treatments to be refrained from due to their effects on the human body.

On the other hand, unlike chemical sterilization methods, sterilization of water to be treated using ultraviolet rays has the characteristics of being able to sterilize effectively with almost no effect on the human body, and has been applied to various production fields. Demand is increasing.

The most effective sterilization method using ultraviolet light is to insert an ultraviolet lamp whose outer periphery is covered with a protective tube into a treatment tank with both ends open. There is a method of sterilizing the water to be treated while it passes around the UV lamp using an ultraviolet sterilizer connected to the feed pipe or drain pipe, but this method using only irradiation with the UV lamp does not sterilize the water. Valid only in the field.

On the other hand, when wastewater is treated by irradiation with ultraviolet or visible light in the presence of semiconductor fine particles such as titanium dioxide, in addition to the sterilizing effect, trichlorethylene, trichloroethane,
It has been disclosed that it is effective in decomposing cyanide ions, dichromate ions, difficult-to-decompose halogen organic compounds, BOD, TOC, etc. (Japanese Patent Laid-Open No. 1-94998).

(Problems to be solved by the invention) This method suspends semiconductor fine particles in treated water,
By irradiating it with ultraviolet or visible light, the electron conduction band of the valence band of titanium oxide excites strong oxidizing power to decompose trichlorethylene, etc. However, titanium oxide suspended in treated water Semiconductor fine particles such as these cannot be discharged or used at the same time as the treated water, so it is costly to separate them from the water after they are discharged from the reaction tank and reuse them, and if they are discharged as is, they may cause secondary pollution. to solve the problem.

As a method for separating semiconductor fine particles from water, a method has been proposed in which they are fixed in a UF polymer membrane and separated by reverse osmosis.

However, in the method of separating two semiconductor fine particles using an OF polymer membrane or a polymer filter, the average contact between the semiconductor fine particles and the industrial wastewater, which is the water to be treated, is insufficient, and therefore sufficient effects cannot be achieved.

In addition, the method of suspending semiconductor particles in industrial wastewater allows sufficient contact between the industrial wastewater and the semiconductor particles, but it is extremely difficult to separate and recover the semiconductor particles from the treated water. Moreover, in order to completely separate and recover these titanium dioxide fine particles, a large-scale separation vessel is required.
There are disadvantages such as the need for an i-device.

In response to this, the inventor of the present application previously proposed a method of separating and recovering fine particles such as titanium dioxide using an ultrafiltration membrane (Japanese Patent Application No. 1-118581). It is necessary to install a 1m minute device using an ultrafiltration membrane outside, which inevitably increases the size of the device, and requires complicated work such as separation and recovery of titanium dioxide and the like.

(Means for Solving the Problems) In view of the above-mentioned circumstances, the present invention has been proposed by inserting into a processing tank a bundle of fibers to which fine semiconductor particles that respond to ultraviolet rays and visible light are attached to the surface of the fibers. The present invention proposes a photochemical wastewater treatment method characterized by treating water to be treated in a treatment tank by irradiating it with ultraviolet rays or sunlight.

Here, the fibers are metal, plastic,
Fibers made of quartz glass or fluororesin can be used, and optical glass fibers are particularly preferred.

Here, as the semiconductor, in addition to titanium dioxide, tungsten trioxide, zinc oxide, etc. can be used, and titanium dioxide supported on platinum is particularly effective.

As the adhesive for attaching these semiconductor fine particles to the surface of the fiber, for example, an ultraviolet curing resin can be used.

In addition, the ultraviolet rays used here have a wavelength shorter than 413 nm when the semiconductor is titanium dioxide,
Preferably, it is necessary to use a light beam of 365n++ or less, and when using tungsten dioxide as the semiconductor,
It is necessary to use a light beam with a wavelength shorter than 459 nm. As such a light source, a medium pressure to high pressure mercury lamp, a xenon lamp, a halogen lamp, etc. can be used.

The ultraviolet rays may be irradiated by placing an ultraviolet lamp outside the processing tank, or by inserting an ultraviolet lamp into the processing tank.

Furthermore, sunlight may also be irradiated from outside the processing tank.

Further, ultraviolet rays or sunlight may be irradiated into the processing tank from the east entrance of the optical glass fiber, or ultraviolet rays may be irradiated into the processing tank by combining these methods.

The irradiation time of ultraviolet rays varies depending on the concentration of harmful substances in wastewater, the intensity of light, etc., and is the time until the harmful substances are substantially decomposed, but it is usually 5 to 20 mw/cm2 and 10 minutes to 1 minute.
It's time.

In this case, it is more effective to add an oxidizing agent to the wastewater that is the water to be treated. As the oxidizing agent, inorganic peroxides such as hydrogen peroxide, hypochlorous acid, and potassium periodate are preferred, and hydrogen peroxide is particularly preferred.

Substances that can be treated with this invention can be subjected to decomposition treatment of organic matter, sterilization treatment of microorganisms, etc., but substances that cannot be decomposed or removed by other methods, such as organic halogen compounds,
Surfactants, organic phosphorus compounds, phenols, BOD,
TOC1 can be sterilized.

(Function) That is, according to the present invention, a bundle of fibers having semiconductor fine particles such as titanium dioxide attached to the surface thereof is inserted into the treatment tank, so that the semiconductor fine particles are dispersed in the water to be treated in the treatment tank. Therefore, by irradiating the water with ultraviolet rays or sunlight, it is possible to effectively decompose organic matter or sterilize microorganisms in the water to be treated.

Further, according to the present invention, semiconductor fine particles can be separated and recovered from the water to be treated by simply pulling the bundle of fibers out of the water to be treated after treatment, so there is no need for large-scale separation and recovery work as in conventional methods.

Furthermore, the semiconductor particles can be easily replaced by simply replacing the fiber to which the semiconductor particles are attached.

On the other hand, when ultraviolet rays or sunlight are irradiated into the processing tank from the entrance of a bundle of optical glass fibers, the ultraviolet rays or sunlight enters the processing tank through between the optical glass fibers to which semiconductor fine particles are attached, making it more effective. Optical treatment of water to be treated can be performed.

(Example) Hereinafter, this invention will be explained in detail based on the illustrated example.

FIG. 1 shows an embodiment of the present invention, in which 1 is a treatment tank into which water to be treated, such as used bath water, is fed through an upper inlet 1a and treated water is discharged through a lower outlet 1b. A high-pressure mercury lamp 3 having a protection tube 2 made of quartz glass or the like on its outer periphery is inserted into the treatment tank 1, and conductive fine particles 4.of titanium dioxide or the like are coated around the protection tube 2 on its surface.・・−
A bundle of glass fibers 58 to which 5. Place...

Semiconductor fine particles 4°... on the surface of the glass fiber 5a.
To attach semiconductor particles, for example, an ultraviolet curable resin is applied to the surface of glass fiber, and then semiconductor fine particles 4.・・・
・Attach and further irradiate with ultraviolet rays to harden the resin.

Also, around the protection tube 2, attach the glass fiber 5a to the east 5.
. . , a frame body 6 having holding holes 6a, . Insert the fiber east 5 with the tips aligned.

Furthermore, a condenser lens 7 is arranged above the frame 6.

In the above configuration, ultraviolet rays are irradiated from the high-pressure mercury lamp 3 to the water to be treated that is fed into the treatment tank 1 from the inlet 1a.

Further, the ultraviolet rays may be irradiated from the outside of the processing tank 1, and in this case, the wavelength of the ultraviolet rays used is about 365 nm.

On the other hand, the sunlight is condensed by the condensing lens 7, and from the tip of the glass fiber bundle 5, the glass fiber 5
The ultraviolet rays are introduced into the wastewater treatment tank 1 from the sides and tips of the glass fibers 5a.

As described above, the treatment tank 1 is irradiated with ultraviolet rays or sunlight, and the used bath water fed into the treatment tank 1 is optically exposed to the semiconductor particles 4 made of titanium dioxide. processing was carried out. As a result, the bath water was purified to the extent that it could be reused.

In this embodiment, the condensing lens 7 is irradiated with sunlight, but it may also be irradiated with ultraviolet rays.

Alternatively, the ultraviolet rays may be irradiated from the outside without inserting the ultraviolet lamp 3 into the treatment tank.

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(Effects of the Invention) In summary, according to the present invention, fibers having conductor fine particles attached to their surfaces are bundled and inserted into a treatment tank for water to be treated, and ultraviolet light is irradiated into the treatment tank. The semiconductor fine particles are introduced into the water to be treated and can perform effective optical treatment of the water to be treated.

In addition, after treatment, the semiconductor particles can be separated and recovered from the water to be treated using a lever that pulls up the fibers. No additional work is required.

Furthermore, if ultraviolet rays are irradiated from the inlet of a bundle of glass fibers, the water to be treated will be incident from between the glass fibers to which the semiconductor fine particles are attached, so that more effective treatment can be performed.

[Brief explanation of the drawing]

Fig. 1 is a vertical sectional side view showing one embodiment of the present invention, Fig. 2 is a sectional view taken along line 1-H of the same as above, and Fig. 3 is a sectional view of III of the same as above.
-III line sectional view, and FIG. 4 is a partially enlarged longitudinal sectional side view of the glass fiber. In the figure, ■ is a treatment tank, 3 is a high-pressure mercury lamp, 4 is semiconductor fine particles, 5 is 0 bundles of glass fibers, and 5a is glass fibers.

Claims (4)

[Claims] (1) A bundle of fibers with semiconductor particles that respond to ultraviolet and visible light attached to their surfaces is inserted into a processing tank,
A photochemical wastewater treatment method, which comprises treating the water in the treatment tank by irradiating the treatment tank with ultraviolet rays or sunlight. (2) The method according to claim 1, wherein an ultraviolet lamp or a medium-pressure to high-pressure mercury lamp is inserted into the treatment tank, and the bundle of fibers is arranged around the lamp. (3) The method according to claim 1 or 2, wherein an optical glass fiber is used as the fiber. (4) The method according to claim 3, wherein the treatment tank is irradiated with ultraviolet rays or sunlight from the entrance of the bundle of optical glass fibers.