JPH0523680A - Treatment and device for photooxidation - Google Patents

Abstract

PURPOSE:To efficiently separate and recover a particulate such as titanium dioxide in a water by passing a water to be treated, in which the particulate such as titanium dioxide is suspended, around an ultraviolet lamp to ultraviolet irradiation treat then passing through a reverse osmosis membrane. CONSTITUTION:The water to be treated is fed from the water feed opening 2 into the reactor vessel 1, in which the catalyst particulate such as titanium dioxide is added and is suspended by the stirring apparatus M. And the water to be treated flows down along the ultraviolet lamp 6 and is irradiated with ultraviolet rays to decompose an organic material in the water to be treated and to sterilizing treat or the like by catalytic action of the titanium dioxide. The treated water is fed to the water passage 8 of the reverse osmosis membrane 9 by the forcibly feeding pump 13 and a part of the water is discharged to outside passing narrow pores of the reverse osmosis membrane and catalyst particulate contained in the water is catched by narrow pores. And next, the cleaning water is forcibly fed to the outside of the reverse osmosis membrane and the catalyst particulate catched by narrow pores is released.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photooxidation treatment method and apparatus using semiconductor fine particles such as titanium dioxide as a catalyst.

[0002]

2. Description of the Related Art Wastewater containing halogen, organic substances, etc., pool water, drinking water, etc. have been decomposed by activated sludge, oxidative decomposition, etc., but these existing treatment methods require a long time and a vast space. Therefore, it cannot be said to be a rational method, and although chemical treatments such as chlorine have been conventionally performed for sterilizing pool water and the like, sterilization treatments by chemicals tend to be refrained from the influence on the human body.

On the other hand, unlike the chemical sterilization method, the sterilization of water to be treated utilizing ultraviolet rays has almost no effect on the human body and effectively decomposes waste water containing hardly-decomposable halogens and sterilization at the same time. Since it has characteristics such as being able to be applied, it is applied to various production fields, and the demand is increasing.

The most efficient sterilization method using ultraviolet rays is that an ultraviolet lamp whose outer periphery is covered with a protective tube is inserted into a processing tank whose both ends are open, and both ends of the processing tank are covered. This is a method of simultaneously decomposing and sterilizing hardly decomposed halogen while the water to be treated passes around the ultraviolet lamp by using a photocatalytic reaction tank connected to a water supply pipe or a drain pipe of the treated water.

On the other hand, it is known that when fine particles such as titanium dioxide are suspended in the water to be treated which is irradiated with ultraviolet rays, a more effective decomposition treatment and sterilization treatment are simultaneously performed by the catalytic action of these fine particles. There is.

[0006]

However, when the two methods are combined as described above and fine particles such as titanium dioxide are suspended in the water to be treated and passed around the ultraviolet lamp to carry out the decomposition purification sterilization treatment. Is extremely difficult to separate and recover titanium dioxide fine particles from the treated water, and these titanium dioxide fine particles are completely separated,
There is a problem that a large-scale separation device is required for recovery.

When fine particles of titanium dioxide or the like are separated by various kinds of membranes and are recovered and reused at the same time as the concentrated liquid, the membranes should be regularly washed so as not to cause clogging of the membranes. I have to.

In view of the above situation, the present invention suspends fine particles of titanium dioxide or the like in the water to be treated and passes them around the ultraviolet lamp to carry out the ultraviolet irradiation treatment, so that titanium dioxide or the like contained in the water after the treatment. The object of the present invention is to propose a method and an apparatus for separating and recovering the above fine particles.

[0009]

In order to solve the above problems, according to the present invention, a reaction tank in which an ultraviolet irradiation lamp is inserted and one or more separation tanks provided with a reverse osmosis membrane are installed in parallel, Is fed with water to be treated in which catalyst fine particles such as titanium dioxide are suspended, and at the same time is irradiated with ultraviolet rays from the lamp to decompose and purify the water to be treated by the catalyst fine particles, and then to treat the water to be treated. The catalyst fine particles contained in the water to be treated are collected by being sent to the separation tank and passing through the reverse osmosis membrane, and the reverse osmosis membrane is further provided with washing water in the direction opposite to the water flow direction of the water to be treated. A photo-oxidation treatment method in which water is passed and the catalyst fine particles collected in the reverse osmosis membrane are separated, and all or part of the washing water containing the separated catalyst fine particles is returned to the reaction tank if necessary. The device is proposed.

The reverse osmosis membrane used in the present invention is, for example, a semipermeable membrane that does not allow particles having a particle size of several to several hundreds in a solution to pass therethrough, and the working pressure thereof is 0.6 to 0.1 per 1,000 ppm of the solution.
It is about 8 kg / cm ² .

In this invention, the water to be treated in which fine particles of catalyst such as titanium dioxide are suspended is irradiated with ultraviolet rays in the treatment tank to be treated, and then the water to be treated is fed into the separation tank and passed through the reverse osmosis membrane. By doing so, the catalyst fine particles are trapped in the pores of the reverse osmosis membrane. Further, when washing water is passed through the reverse osmosis membrane in a direction opposite to the direction of the water to be treated, the catalyst fine particles trapped in the pores of the reverse osmosis membrane are separated. Then, a part or all of the washing water containing the catalyst fine particles is returned to, for example, the processing tank to reuse the catalyst fine particles.

That is, in the present invention, the reverse osmosis membrane can be used to effectively separate and recover the catalyst fine particles such as titanium dioxide used in the photooxidation treatment method.

In the present invention, as the type of the reverse osmosis membrane, commercially available tubular type, multi-tube type, plate type, spiral type, hollow fiber type and the like can be used.

Depending on the type of water to be treated, a part of the two or more separation tanks may be replaced with a separation tank having an ultrafiltration membrane.

Further, as the ultraviolet irradiation lamp, a high pressure mercury lamp, a medium pressure mercury lamp, a low pressure mercury lamp or the like can be used depending on the type of water to be treated.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on the illustrated embodiments. FIG. 1 shows an embodiment of the present invention.
Is a reaction tank having a water supply port 2 in the upper part and a drain port 3 in the lower part.
An ultraviolet lamp 6 having a quartz protective tube 5 provided on the outer periphery thereof is inserted into the inside of the container. A stirrer M is provided at the bottom or side of the reaction tank 1.

A separation tank 7 is provided with a reverse osmosis membrane 9 having a water passage 8 whose both ends are open in the center of the separation tank 7, and the bottom of the separation tank 7 is connected to the lower end of the water passage 8. Water inlet
10 is provided, and further the separation tank 7 corresponding to the upper end of the reverse osmosis membrane 9
A drainage pipe 11 is provided on the upper part of.

On the other hand, a lower communication path 12 is provided between the drainage port 3 of the reaction tank 1 and the water supply port 11 of the separation tank 7, and a pressure pump 13 is interposed in the communication path 12.

A branch passage 16 which is switched by a valve 15 is provided between the upper end of the water passage 8 of the reverse osmosis membrane 9 and the upper portion of the reaction tank 1, and the upper end of the branch passage 16 is connected to the upper connecting passage 14. To do.

In the photooxidation treatment apparatus as described above, the water to be treated is supplied from the water supply port 2 to the reaction tank 1, where catalyst fine particles 17, such as titanium dioxide, are added. In the reaction tank 1, the catalyst fine particles 17, ... Are suspended in water by the stirring device M. Further, while being heated by the heater 4, it flows down along the ultraviolet lamp 6 in such a state, is irradiated with ultraviolet light during this time, and decomposes and sterilizes organic matter in the water to be treated by the catalytic action of fine particles of titanium dioxide. Done.

The treated water is sent to the water passage 8 of the reverse osmosis membrane 9 through the lower connecting passage 12 by the pressure feed pump 13.

A part of the water sent to the water passage 8 is a reverse osmosis membrane 9
Through the pores 9a to escape to the outside of the reverse osmosis membrane 9, and during this time, the catalyst fine particles 17, ... contained in the water are collected in the pores 9a. The water that has escaped from the reverse osmosis membrane 9 is discharged to the outside through the drain pipe 11.

The rest of the water sent to the water passage 8 is returned to the reaction tank 1 through the upper connecting passage 14. The drain pipe 11
The ratio of the amount of water discharged to the outside through the water and the amount of water returned to the reaction tank 1 is, for example, 6: 4.

Next, the wash water is pumped to the outside of the reverse osmosis membrane 9. The wash water sent under pressure is sent through the pores 9a into the water passage 8 while releasing the catalyst fine particles 17, ... Collected in the pores 9a.

In this way, the cleaning water containing the catalyst fine particles 17, ... Is sent to the water passage 8. This may be taken out as it is to recover the catalyst fine particles 17 ,.
You may make it open 15 and return this washing water to the reaction tank 1 through the branch path 16 and the upper connection path 14.

[0026]

In summary, according to the present invention, fine particles such as titanium dioxide are suspended in the water to be treated and passed through the periphery of the infrared lamp to carry out the ultraviolet irradiation treatment, so that the titanium dioxide contained in the treated water is treated. It is possible to efficiently separate and collect fine particles such as.

[Brief description of drawings]

FIG. 1 is a schematic view showing an embodiment of the present invention.

FIG. 2 is an enlarged view of the main part of the above.

[Explanation of symbols]

1 reaction tank 7 separation tanks 9 Reverse osmosis membrane 13 Pressure pump 17,… Catalyst fine particles

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI technical display location C02F 1/44 H 8014-4D K 8014-4D 9/00 Z 6647-4D

Claims (3)

[Claims] 1. A reaction tank in which an ultraviolet irradiation lamp is inserted and one or more separation tanks equipped with a reverse osmosis membrane are provided side by side, and water to be treated in which catalyst fine particles are suspended is fed into the reaction tank. At the same time, ultraviolet rays are emitted from the lamp to purify and treat the water to be treated with catalyst fine particles, and then the water to be treated is fed into a separation tank,
Catalytic fine particles contained in the water to be treated are collected by passing through the reverse osmosis membrane, and further, wash water is passed through the reverse osmosis membrane in a direction opposite to the water flow direction of the water to be treated. A method for photooxidation treatment, characterized in that the catalyst fine particles collected in (1) are separated, and all or part of the washing water containing the separated catalyst fine particles is returned to the above reaction tank if necessary. 2. The method according to claim 1, wherein a part of the two or more separation tanks is replaced with a separation tank equipped with an ultrafiltration membrane.
Method described in section. 3. A photo-oxidation treatment apparatus in which a reaction tank having an ultraviolet irradiation lamp inserted therein and a separation tank having a reverse osmosis membrane are arranged side by side via a pressure pump.