JPH0687957B2 - Multi-function - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention provides metal ions and nonionic substances contained in water used in various fields such as nuclear power generation, medical care, pharmaceuticals, and precision electronics industry. The present invention relates to a useful novel multi-functional permembrane that is simultaneously removed and purified.

(Prior Art) In the conventional water treatment technology, non-ionic clads, fine particles, bacterial cells and the like have been removed in advance with a microfilter, a cake or the like, and then dissolved metal ions have been removed with an ion exchange resin or the like.

These treatment methods have complicated operations, require a large amount of ion exchange resin, have a relatively short life of the ion exchange resin, and have problems such as disposal after use.

Particularly in nuclear power generation, the reduction of customers of radioactive waste is a major issue, and it is desired to combine chemical adsorption and removal with physical over-process in terms of safety and economy. Various methods have been taken to overcome these problems, but it has been difficult for any of the methods to simultaneously provide an ion adsorption function and a fine particle removal function.

In particular, the method of hydrophilizing the micro-permeation membrane and the method of introducing the ion-exchange group are being studied, but it is possible to completely overcome the above problems because the pores are fitted with the addition of the function and the water permeability decreases. It was difficult.

(Problems to be Solved by the Present Invention) The present invention efficiently removes nonionic fine particles in a water treatment technology when imparting ion adsorption performance to a porous micropermeation membrane without lowering water permeability. The purpose is to provide a multi-function membrane capable of doing things.

(Means for Solving Problems) As a result of intensive studies on means for achieving the above-mentioned object, the present inventors have found that the following means can be achieved.

The material of the base material film is a polyolefin, a sulfonic acid group, a carboxylic acid group, a phenolic hydroxyl group on a porous micropermeation film made of a copolymer of olefin and halogenated olefin,
When graft-polymerizing a polymerizable monomer having a phosphonic acid group and an amidoxime group or capable of being exchanged, the presence of a monomer having two or more polymerizable groups causes the formation of a dissolved ionic and nonionic substance. It has been found that the objective can be achieved by a multi-function membrane that efficiently removes.

Hereinafter, the present invention will be described in more detail.

The polyolefin of the base material to be graft-polymerized in the present invention, an olefin and a halogenated olefin copolymer are polyethylene, polypropylene, polysulfone, polytetrafluoroethylene, or ethylene propylene, butene,
It is selected from homopolymers or copolymers of hexene, tetrafluoroethylene, chlorotrifluoroethylene.

The polymerizable monomer grafted to the base film is a reactive monomer having a functional group or capable of being exchanged with the functional group, such as acrylic acid, methacrylic acid, fluorovinylcarboxylic acid, vinylsulfonic acid, styrene and styrene. Sulfonic acid, fluorovinylsulfonic acid, paravinylphenol, vinyl acetate, acrylonitrile, vinylidene cyanide, acrolein, dimethylacrylamide, diethylaminopropylacrylamide, glycidyl methacrylate and the like are used.

As the monomer having two or more polymerizable groups used in the present invention, divinylbenzene, polyethylene glycol dimethacrylate having a degree of polymerization of 9 or less, polyethylene glycol diacrylate, triallyl isocyanurate and the like are used. The coexistence ratio of the monomer having a functional group and the monomer having two or more vinyl groups is preferably in the range of 97: 3 to 80:20, and above and below,
Even if the ion adsorption performance is introduced, the water permeation performance deteriorates, and it is impossible to exert the function as a multi-functional permeation membrane.

The ionizing radiation used in the graft polymerization of the present invention is α
Rays, β rays, γ rays, accelerated electron rays, X rays and the like are available, but accelerated electron rays or γ rays are preferable for practical use.

As a method of graft-polymerizing a base material and a polymerizable monomer according to the present invention, a simultaneous irradiation method in which the base material and the monomer are irradiated with radiation in the coexistence, and only the base material is previously irradiated with radiation. After that, any of the pre-irradiation methods of contacting with the monomer is possible, but preferably the pre-irradiation method is less likely to generate side reactions other than the graft polymerization.

The method of contacting the base material and the monomer in the graft polymerization includes liquid phase polymerization in which the monomer is directly contacted with liquid monomer and gas phase polymerization in which the monomer is contacted in vapor or vaporized state. It is possible.

Hereinafter, the configuration and effects of the present invention will be specifically described with reference to Examples, but the present invention is not limited to any of them.

(Example) Example 1 A porous hollow fiber membrane made of polyethylene (inner diameter 0.62 mmφ, outer diameter
1.24mmφ, average pore diameter 0.1μm, electron accelerator (accelerating voltage 2
After irradiating 200KGy in a nitrogen atmosphere using MeV and electron beam current 1mA), a mixed solution of glycidyl methacrylate (GMA) and divinylbenzene (DVB) in which dissolved oxygen was freeze-deaerated beforehand (DVB mole fraction 3%, 5% %, 10%) into a glass ampoule, place the reaction solution at the bottom, place 60 mesh stainless steel in the center, and place the irradiated hollow fiber membrane at the top.
After degassing to ^-4 mmHg under reduced pressure, the reaction was carried out in a constant temperature bath at 40 ° C for 5 to 10 hours to obtain a 100 to 200% graft membrane. This graft membrane was subjected to phosphorylation reaction at 80 ° C. for 1 hour in a concentrated phosphoric acid solution. As a result of determining the functional group concentration by ion titration, 0.5 to 1.5 meq / g of phosphate group was introduced. Using this hollow fiber membrane, a water permeability test was conducted at a pressure of 1 kg / cm ² .

The results are shown in Fig. 1.

Comparative Example 1 Using the same hollow fiber membrane as in Example 1, graft reaction and phosphorylation reaction were carried out in the same manner as in Example 1 without mixing DVB with glycidyl methacrylate in the reaction solution, and the reaction time was changed to obtain a graft ratio of 100. From 200%, functional group concentration from 0.5
1.5 mep / g of resin was obtained. Figure 1 shows the results of the water permeability test of this membrane.
Also described in.

In the comparative example in which DVB was not mixed, the water permeability was 0.01 m ³ / m ² · hr or less, and the effect of adding DVB according to Example 1 was clearly shown.

Example 2 Polyethylene porous flat membrane (film thickness 100 μm, average pore size
0.1 μm) electron accelerator (accelerating voltage 2 MeV electron beam current 1 mA)
After irradiating with 200 kgy in a nitrogen atmosphere, dissolved oxygen was deoxidized with nitrogen gas in advance.

A mixed solution of 45 parts of acrylic acid (AAC), 5 parts of tetraethylene glycol dimethacrylate (4G) and 50 parts of water (sulfuric acid No. 1
0.25% iron ammonium) and 30 in a glass ampoule
The reaction was carried out at 1 ° C for 1 hour to obtain a membrane having a graft ratio of 40%. This was subjected to a water permeability test in the same manner as in Example 1, and as a result, 1.4 m ³ / m ² ·
It was hr.

Comparative Example 2 The same base material as in Example 2 was used, except that 4G was not added to the reaction solution, and the same procedure as in Example 2 was carried out. As a result, the graft ratio was 65% and the water permeation rate was 0.005 m ³ / m ² ·. It was hr. As a result
A large difference in water permeability was observed depending on whether 4G was added or not.
It became clear that the effect of addition of.

Example 3 Porous polypropylene membrane (film thickness 100 μm, average pore size 0.1 μm
m) in a glass container and irradiated with cobalt-60 gamma rays at a dose rate of 10KGy / hr for 20 hours in dewarbin cooled with dry ice and methanol, and then degassed 90 parts of acrylonitrile and triallyl isocyanurate 10
Part was introduced into a glass container, brought into contact with the substrate and reacted at 50 ° C. for 4 hours to obtain a membrane having a graft ratio of 95%. This was reacted with 3% hydroxylamine hydrochloride in methanol at 80 ° C. for 3 hours to introduce 4.5 mmol of amidoxime group per gram of the substrate.

The water permeability of this was measured in the same manner as in Example 1, and the result was 1.6 m ³ /
I got m ² · hr.

Comparative Example 3 Graft polymerization was carried out by the method of Example 3 without adding triallyl isocyanurate to the reaction solution, and the same operation as in Example 3 was carried out except that the graft ratio was 120% and the water permeation rate was 0.002 m ^3. / m ² · hr was obtained.

From this result, it was possible to introduce a functional group into the porous membrane by adding triallyl isocyanurate without lowering the water permeability.

(Effects of the Invention) As shown in FIG. 2, the method of the present invention imparts an ion adsorption function without impairing the permeation performance of the porous polymer membrane, and clearly shows a breakthrough point. It was possible to provide a multi-functional permembrane having excellent physical separation function.

[Brief description of drawings]

FIG. 1 is a diagram showing the relationship between the graft ratio and the water permeation performance of the permembranes made of the graft polymers obtained in Example 1 and Comparative Example 1 of the present invention. FIG. 2 is a diagram showing the superpermeable performance of the permeation membranes obtained in Examples 1 and 3 of the present invention.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location C08J 5/18 CES 9267-4F

Claims (5)

[Claims] 1. When a hydrophilic film and an ion-adsorptive functional group are introduced into a porous film composed of a polyolefin film or a copolymer of an olefin and a halogenated olefin as a material of a substrate film, a mono-functional film having two or more polymerizable groups A method for producing a multi-function filtration membrane having both an ion adsorption function and a fine particle removal function, which is characterized in that 3 to 20 mol% of a monomer coexists. 2. The method according to claim 1, wherein the structure of the base film is a flat film or a hollow fiber, and the average pore diameter is 0.01 μm to 10 μm. 3. A polymerizable monomer for introducing an ion-adsorptive functional group has a sulfonic acid group, a carboxylic acid group, a phenolic hydroxyl group, a phosphonic acid group or an amidoxime group, or is exchanged with these groups. The method according to claim 1, which is a hydrocarbon-based polymerizable monomer or a halogen-containing polymerizable monomer that is capable of being contained in an amount of 0.1 to 8 milliequivalents per gram of film weight. 4. The method according to claim 1, wherein the functional introduction method is graft polymerization using ionizing radiation. 5. A polymer having a degree of polymerization n of a monomer having two or more polymerizable groups selected from polyethylene glycol dimethacrylate, divinylbenzene, and triallyl isocyanate having 2 ≦ n ≦ 9. The method according to claim 1.