JPH06102192B2 - Photochemical wastewater treatment method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a simple optical treatment method of waste water for use with semiconductor fine particles such as titanium dioxide as a catalyst.
For example, it relates to a method suitable for treating trichlorethylene, trichloroethane, cyan ion, dichromate ion, hardly decomposed halogen organic compound, BOD, TOC and the like.

(Prior Art) Conventionally, chemicals such as chlorine have been used for sterilizing water and the like, but sterilization by chemicals tends to be refrained from the effects on the human body.

On the other hand, sterilization of water to be treated using ultraviolet rays, unlike chemical sterilization methods, has characteristics such as effective sterilization treatment with almost no effect on the human body, and is applied to various production fields. Demand is increasing.

It is said that the most effective sterilization method using this ultraviolet ray is to insert an ultraviolet lamp whose outer periphery is covered with a protection tube into a treatment tank with both ends open, and to treat water to be treated at both ends of the treatment tank. There is a method of sterilizing while the water to be treated passes around the ultraviolet lamp by using an ultraviolet sterilizer connected to the water supply pipe or the drain pipe. Effective only in the field.

On the other hand, when the treatment of the wastewater by irradiation with ultraviolet rays or visible light is performed in the presence of semiconductor fine particles such as titanium dioxide, trichloroethylene, trichloroethane, in addition to the bactericidal effect,
It is disclosed that it has an effect on the decomposition treatment of cyanide ions, dichromate ions, hardly decomposed halogenated organic compounds, BOD, TOC, etc. (JP-A-1-94998).

(Problems to be Solved by the Invention) This method involves suspending semiconductor particles in treated water,
By irradiating ultraviolet or visible light, the cooperative oxidation power is excited by the electron conduction band of the valence band of titanium oxide to decompose trichlorethylene etc., but titanium oxide suspended in treated water is used. Since it is not possible to discharge or use semiconductor fine particles such as water at the same time as treated water, it requires a large cost to separate them from water and reuse them after discharging them from the reaction tank. Raise the problem of.

As a method for separating semiconductor particles and water, a method of fixing in a UF polymer membrane and separating by reverse osmosis has been proposed.

However, in the method of separating the semiconductor fine particles with the UF polymer membrane or the polymer filter, the average contact between the semiconductor fine particles and the waste water which is the water to be treated is not sufficient, and therefore a sufficient effect cannot be obtained.

Regarding the method of suspending the semiconductor fine particles in the waste water for use, it is possible to make sufficient contact between the waste water for use and the semiconductor fine particles, but it is extremely difficult to separate and recover the semiconductor fine particles from the treated water. In addition, there is a problem that a large-scale separation device is required to completely separate and recover these titanium dioxide fine particles.

On the other hand, the inventor of the present application has previously proposed a method for separating and recovering fine particles such as titanium dioxide using an ultrafiltration membrane (Japanese Patent Application No. 118581/1991). However, even in this method, it is necessary to provide a separation device with an ultrafiltration membrane outside the device, and it is inevitable that the device becomes large, and moreover, complicated work such as separation and recovery of titanium dioxide and the like is required. .

(Means for Solving the Problems) In view of the above situation, the present invention inserts a bundle of fibers having semiconductor fine particles responsive to ultraviolet rays and visible light on the surface thereof into a treatment tank, and The present invention proposes a method for treating photochemical wastewater, which comprises irradiating ultraviolet rays or sunlight to the treated water in the treatment tank.

Here, the fiber is made of metal, plastic,
Quartz glass and fluororesin fibers can be used, and optical glass fibers are particularly preferable.

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

An ultraviolet curable resin, for example, can be used as the adhesive for adhering these semiconductor particles to the surface of the fiber.

Further, as the ultraviolet used here, when the semiconductor is titanium dioxide, it is necessary to use a light beam having a wavelength shorter than 413 nm, preferably a light beam having a wavelength of 365 nm or less, and when using tungsten trioxide as a semiconductor, 459 nm. It is necessary to use shorter wavelength light. As such a light source, a medium or high pressure mercury lamp, a xenon lamp, a halogen lamp or the like can be used.

Ultraviolet rays may be irradiated by placing an ultraviolet lamp outside the processing tank, or by inserting an ultraviolet lamp in the processing tank and irradiating it.

Moreover, you may make it irradiate also about a solar ray from the exterior of a processing tank.

Further, ultraviolet rays or sun rays may be irradiated into the processing tank from the entrance of the bundle of optical glass fibers, or ultraviolet rays may be irradiated into the processing tank by combining these methods.

The irradiation time of ultraviolet rays depends on the concentration of harmful substances in the wastewater used, the intensity of light, etc., and is the time until the harmful substances are substantially decomposed, but it is usually 5 to 20 mw / cm ² and 10 minutes to 1 hour. is there.

In this case, it is more effective to add an oxidizer to the waste water which is the water to be treated. The oxidizing agent is preferably an inorganic peroxide such as hydrogen peroxide, hypochlorous acid or potassium periodate, and hydrogen peroxide is particularly preferable.

The substances that can be treated by the present invention can be decomposed with organic substances, sterilized with microorganisms, etc., but cannot be decomposed or removed by other methods, for example, organic halogen compounds,
Surfactants, organophosphorus compounds, phenols, BOD, TO
C, can be sterilized.

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

Further, according to the present invention, the semiconductor fine particles can be separated and collected from the water to be treated only by pulling up the bundle of fibers from the water to be treated after the treatment, so that a large-scale separation and collection work unlike the conventional case is not required.

Further, the semiconductor fine particles can be easily exchanged by simply replacing the fiber having the semiconductor fine particles on the surface.

On the other hand, when ultraviolet rays or solar rays are irradiated into the processing tank through the entrance of the bundle of optical glass fibers, the ultraviolet rays or solar rays are injected into the processing tank from between the optical glass fibers to which the semiconductor fine particles are adhered, which is more effective. Optical treatment of water to be treated can be performed.

(Example) Hereinafter, the present invention will be described in detail based on an illustrated example.

FIG. 1 shows an embodiment of the present invention, in which 1 is used to feed water to be treated such as used bath water through an upper inlet 1a,
A treatment tank that discharges treated water from the lower outlet 1b.
A glass fiber in which a high-pressure mercury lamp 3 having a protective tube 2 made of quartz glass or the like on its outer periphery is inserted into the interior of the glass, and semiconductor particles 4, such as titanium dioxide, are attached to the surface around the protective tube 2. Arrange the bundle 5a of 5a, ....

To adhere the semiconductor fine particles 4, ... To the surface of the glass fiber 5a, for example, an ultraviolet curable resin is applied to the surface of the glass fiber, and then the semiconductor fine particles 4 ,.
Further, ultraviolet rays are irradiated to cure the resin.

Further, in order to arrange the bundles 5 of glass fibers 5a around the protective tube 2, a frame body 6 having holding holes 6a at appropriate intervals is provided around the protective tube 2 at the upper end of the processing tank 1. This holding hole 6
A bundle of glass fibers 5 is inserted into a, ... with the tips aligned.

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

In the above structure, the high pressure mercury lamp 3 irradiates the water to be treated, which is fed into the treatment tank 1 through the inlet 1a, with ultraviolet rays.

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

On the other hand, the sun's rays are collected by the condenser lens 7, and the glass fiber 5a
Then, the ultraviolet rays are irradiated into the waste water treatment tank 1 from the side portion or the tip portion of the glass fiber 5a.

As described above, the used bath water fed into the treatment tank 1 by irradiating the treatment tank 1 with ultraviolet rays or sunlight is optically treated in the presence of the semiconductor fine particles 4, ... Processed. As a result, the bath water was purified to the extent that it could be reused.

Although the condensing lens 7 is irradiated with the sun rays in this embodiment, it may be irradiated with ultraviolet rays.

Alternatively, the ultraviolet lamp 3 may not be inserted into the processing tank 1, and ultraviolet rays may be irradiated from the outside.

(Effects of the Invention) In summary, according to the present invention, the fibers having semiconductor particles adhered to the surface are bundled and inserted into the treatment tank of the water to be treated, and the treatment tank is irradiated with ultraviolet rays. Is dispersed in the water to be treated, and effective optical treatment of the water to be treated can be performed.

Also, after the treatment, it is possible to separate and collect the semiconductor fine particles from the water to be treated simply by pulling up the fiber.Therefore, after the treatment, the semiconductor fine particles suspended in the water to be treated are separated and collected from the water to be treated. Does not need

Further, when ultraviolet rays are irradiated from the bundled entrance of the glass fibers, they are made to enter the water to be treated from between the glass fibers to which the semiconductor fine particles adhere, so that more effective treatment can be performed.

[Brief description of drawings]

1 is a longitudinal side view showing an embodiment of the present invention, FIG. 2 is a sectional view taken along the line II-II of the above, FIG. 3 is a sectional view taken along the line III-III of the above, and FIG. FIG. In the figure, 1 is a treatment tank, 3 is a high pressure mercury lamp, 4 is semiconductor fine particles, 5 is a bundle of glass fibers, and 5a is glass fibers.

Claims (1)

[Claims] 1. A high-pressure mercury lamp having a protection tube provided on the outer periphery thereof is inserted into the inside of a processing tank, and a frame body having a plurality of holding holes is provided around the protection tube at the upper end of the processing tank, and the holding hole is provided in the holding hole. A bundle of optical glass fibers having semiconductor fine particles responsive to ultraviolet rays and visible light adhered to the surface thereof are detachably held and the optical glass fibers are suspended in a treatment tank. Ultraviolet rays are further irradiated from the inlet of the bundle of optical glass fibers with ultraviolet rays or sunlight to treat the water to be treated in the treatment tank, and after the treatment, the optical glass fibers are pulled up to remove the semiconductor fine particles from the water to be treated. A method for treating photochemical wastewater, characterized in that it is separated and collected.