JPS6154237A - Manufacture of uranium-adsorbable composite fiber-shaped material - Google Patents

Abstract

PURPOSE:To increase the durability of the titled composite fiber-shaped material remarkably by mixing closely the fine particles of uranium-adsorbable organic high molecular substance with inorganic fine powder beforehand, in case of manufacturing the uranium-adsorbable composite fiber-shaped material having the pulverized fibril-like structure by complexing the above-mentioned fine particles of organic high molecular substance and the inorganic fine powder into the fiber-shaped material. CONSTITUTION:The uranium-adsorbable composite fiber-shaped material is manufactured by complexing both the fine particles of uranium-adsorbable and water-insoluble organic high molecular substance and inorganic fine powder to the inside or the neighborhood of the surface of fiber-formable high molecular substance having the pulverized fibril-like structure. In this case, the uranium- adsorbable fine particles and the inorganic fine powder are closely mixed beforehand, by using a mixer and a ball mill or the like.

Description

Detailed Description of the Invention <Industrial Application Field> The present invention provides a fibrous material having a fine fibrillar structure, which is a composite of uranium-adsorbing organic polymeric material fine particles and inorganic fine powder in a fibrous material. Concerning methods of manufacturing things.

<Prior Art> Inorganic adsorbents such as cititanic acid or a composite of activated carbon and titanic acid have been proposed and extensively studied.

Recently, polymer compounds in which groups such as β-diketones, dithiocarbamates, amidoximes, phosphines, and phosphones are bonded in unique configurations have been synthesized, and their uranium selective adsorption performance has been found to be superior to that of inorganic adsorbents. Ta.

A fibrous adsorbent is proposed in JP-A-57-10332. This is a method in which a cyan group-containing resin is made into fibers and then uranium-adsorbing groups are introduced through chemical treatment.

Compounding an inorganic filler into a finely fibrillated fibrous material has been proposed in Japanese Patent Publication No. 51-30605. In this case, the inorganic filler is added for the purpose of improving the beatability of the fine pulp-like material and improving the opacity of the pulp, and has nothing to do with the adsorption of special substances. Also, JP-A-55-9
9345 is a composite of inorganic fine powder that serves as a catalyst in fine fibrils.

We are proposing a method to develop the performance of a particulate catalyst. JP-A-53-104586 proposes a method for obtaining an adsorbent for collecting uranium by compounding inorganic fine particles having uranium adsorption properties with a fiber-forming polymeric substance. In each of the above proposals, inorganic fine particles, which are generally stable to heat and solvents, are compounded in a fiber-forming polymeric substance. It has not been previously known that fine particles of an organic polymer compound such as a uranium-adsorbing resin can be composited into a fiber-forming polymer material and that a composite fibrous material exhibiting excellent performance can be obtained.

<Problems to be Solved by the Invention> Uranium-adsorbing organic polymer compounds are generally used in the form of spheres, granules, or chips for ease of handling; There are problems with uranium-adsorbing resins molded into

First, compared to finely powdered resins, the effective surface area involved in adsorption is significantly reduced, resulting in a reduced adsorption rate. Furthermore, resins are generally brittle, and when brought into contact with seawater, the surface layer is ground into fine particles due to contact between particles, and a portion of the adsorbent resin flows out. On the other hand, fine powder resin has a large specific surface area and is advantageous in terms of adsorption rate, but cannot be used because of loss due to spillage and poor handling.

Although fibrous adsorbents are attracting attention as they exhibit revolutionary uranium adsorption amounts and adsorption speeds compared to conventional adsorbents, these fibrous adsorbents also have major problems.

First, the surface layer of the fiber has been chemically modified to become a brittle adsorbent compound that is different from the inner layer.

As a result, the abrasion resistance and strength of the fibers are significantly reduced. In addition, the fibers themselves are susceptible to chemical modification, so even if good results are obtained during the initial adsorption, the fibers gradually deteriorate due to the chemicals used during uranium recovery.

Eventually, the fiber shape cannot be maintained.

The present inventors previously disclosed in Japanese Patent Application No. 58-1<5713 that uranium-adsorbing organic polymeric fine particles or uranium-adsorbing organic polymeric fine particles and inorganic fine powder are combined into fiber-forming polymeric particles. We proposed that a fibrous adsorbent with high uranium adsorption rate, durability, and excellent handling properties could be obtained by combining uranium into fine fibrils. As a result of intensive studies to obtain a fibrous adsorbent having a higher uranium adsorption rate, the inventors of the present invention have found that by closely mixing uranium-adsorbing organic polymer material fine particles and inorganic fine powder in advance, the uranium-adsorbing organic polymer material The present invention was achieved by discovering that a fibrous adsorbent having an unprecedentedly high uranium adsorption rate can be obtained by compounding fine material particles into fine fibrils with their surfaces covered with inorganic fine powder.

, <Means to Solve the Problems> In the method for producing a uranium-adsorbing composite fibrous material of the present invention, uranium-adsorbing and water-insoluble organic polymer particles and inorganic fine powder are combined into fine fin IJs. ) When producing a uranium-adsorbing composite fibrous material composited inside or near the surface of a fiber-forming polymeric substance having a ribbon-like structure, the uranium-adsorbing fine particles and the inorganic fine powder are intimately mixed in advance. Also features:

This is a treatment for introducing water-insoluble uranium adsorbing groups.After organic polymeric fine particles and inorganic fine powders capable of imparting silane adsorption properties are combined inside or near the surface of a fiber-forming polymeric substance with a fine fibrillar structure. When producing a uranium-adsorbing composite fibrous material that imparts uranium adsorption properties to the organic polymeric material fine particles in the composite fibrous material by a uranium-adsorbing group introduction treatment, the organic polymeric material fine particles and the inorganic fine powder are combined with each other. It is characterized by intimately mixing them in advance.

The present invention will be explained in more detail below.

The uranium-adsorbing organic polymer fine particles used in the present invention include a group having a strong affinity for uranium, which exists in seawater as a uranyl ion with a quasi-thousand hexacoordination structure, and a high equilibrium constant; Another example is one in which a compound with a high equilibrium constant and a ring pore size suitable for accommodating uranyl ions is chemically bonded to a water-insoluble thermoplastic resin or thermosetting resin. Groups that selectively coordinate uranyl ions include amidoxime groups, dithiocarbamate groups, and phosphonic groups, and organic polymeric substances containing these groups are generally referred to as amidoxime-type resins.

They are called dithiocarbamate resins and phosphonic type resins.

Compounds that selectively coordinate uranyl ions include macrocyclic hexaketones, macrocyclic hexacarboxylic acids, phosphoric acid, salicylic acid, and hydroxamic acid, but these compounds are immobilized on water-insoluble resins. It is used as

As the water-insoluble resin, a linear polymer substance or a three-dimensional polymer substance is used. Preferred examples include vinyl copolymers and polyamides, specifically polystyrene, styrene-acrylonitrile copolymers, styrene-divinylbenzene copolymers, styrene-acrylonitrile-divinylbenzene copolymers, Resins modified with styrene-acrylonitrile-tetraethylene glycol dimethacrylate copolymer, acrylonitrile-divinylbenzene-tetraethylene glycol dimethacrylate copolymer, polyethyleneimine-polyvalent carboxylic acid condensate, etc. can be mentioned. The most preferred uranium adsorbing organic polymer substance fine particles are:

Examples include amidoxime type resins in which diamidoxime groups are introduced into acrylonitrile-divinylbenzene-tetraethylene glycol dimethacrylate copolymer by hydroxylamine treatment.

The average particle size of the uranium-adsorbing organic polymer material particles is 10
The average particle size is 0 μm or less and the maximum particle size is 300 μm or less, preferably the average particle size is 50 μm or less and the maximum particle size is 100 μm or less, and more preferably the average particle size is 20 μm or less and the maximum particle size is 50 μm or less. In addition, uranium-adsorbing organic polymer material fine particles are
Although it generally depends on the particle size, it can be compounded by 0.1 to 5 times the weight of the fiber-forming polymeric substance.

Specifically, the inorganic fine powder to be intimately mixed with the uranium-adsorbing organic polymer substance organic polymer substance fine particles includes silica,
Examples include alumina, talc, kaolin, clay, titanium oxide, carbon, and iron oxide. Generally, a hydrophilic inorganic fine powder with a large oil absorption is preferred. Water-repellent or hydrophobic inorganic fine powders are generally not preferred. The average primary particle diameter of the inorganic fine powder is 10 μm or less, preferably 3 μm or less.
It is preferable that the average particle size of the uranium-adsorbing organic polymer substance fine particles is smaller than μm.

The inorganic fine powder is preferably added in an amount of 0.1 to 5 times, preferably 0.5 to 2 times, the weight of the fine particles of the ural-adhesive organic polymer substance.

In the present invention, it is necessary to intimately mix the uranium-adsorbing organic polymeric substance fine particles and the inorganic fine powder in advance.

The term "intimate mixing" as used herein means that as a result, inorganic fine powder is attached to the surface of the uranium-adsorbing organic polymer material fine particles, resulting in a state in which the surface of the particles is covered with powder. The ratio at which the particle surface is dusted with powder is such that at least 30 inches of the entire particle surface must be covered), preferably 50 inches or more, and more preferably 80% or more.

Mixers and ball mills are commonly used as a means of intimate mixing to achieve this state.

There are grinders or shakers, which are used in air or in a solvent.

The internal form of the uranium-adsorbing composite fibrous material obtained (by intimate mixing) is such that the inorganic fine powder is almost completely arranged around the uranium-adsorbing fine particles, covering the uranium-adsorbing fine particles. As a result, the surface of the uranium-adsorbing fine particles can be effectively contacted with seawater, and the uranium-adsorbing fine particles and the inorganic fine powder exist independently inside the fibrous material. Most surfaces of the adsorptive fine particles are covered with a matrix polymer. Therefore, the surface of the uranium-adsorbing fine particles cannot come into contact with seawater as effectively as in the case of intimate mixing.

As the fiber-forming polymeric substance, a linear polymeric substance that can be dissolved in an organic solvent is used. Preferred examples include vinyl copolymers and cellulose derivatives. Specifically, polyethylene, polypropylene, polybutene
1, Poly-4-methylbentene-1. Polyacrylonitrile, styrene-acrylonitrile copolymer, vinyl chloride.

Examples include polymers further modified with cellulose acetate, partially esterified polyvinyl alcohol, and the like. Particularly preferred polymers include crystalline polyolefins, acrylonitrile (co)polymers, and cellulose derivatives.

In addition to these matrix polymers, ethylene-vinyl acetate copolymer, ethylene-acrylic acid copolymer metal salt, etc. may be added for the purpose of imparting hydrophilicity, although the fiber-forming properties are insufficient. good.

When water is added to the spinning dope to form a dispersion polymer solution emulsion, a water-soluble polymer can be dissolved in the aqueous phase to impart hydrophilicity to the fibrous material formed. As a water-soluble polymer.

For example, polyvinyl alcohol, polyacrylic acid.

Polyacrylamide, modified starch, and carboxymethyl cellulose are used.

The organic solvent used in the present invention must dissolve the fiber-forming polymeric substance and be substantially inert to the uranium-adsorbing resin particles and inorganic fine particles. Solvents suitable for these conditions include pentane,
Hydrocarbons such as hexane, cyclohex f7, benzene, and styrene chloride.

Rio O*, I+/mu, ! 2! ] Carbon chloride, trichloroethylene, etc. (D 8C1) ionized hydrocarbons, methyl alcohol.

Alcohols such as ethyl alcohol and inpropyl alcohol, and nitriles such as acetonitrile.

Examples include ketones such as acetone and ethyl methyl ketone, ethers such as ethyl ether and tetrahydrofuran, esters such as methyl acetate and ethyl acetate, and mixtures thereof. These solvents are appropriately used depending on the characteristics of the fiber-forming polymer substance used.

When uranium-adsorbing fine particles or inorganic fine powder are uniformly dispersed in the spinning dope, it is preferable to add a surfactant for the purpose of imparting hydrophilicity. As the surfactant, oily or hydrophilic anionic, cationic, amphoteric and nonionic surfactants, high molecular weight surfactants, and low molecular weight surfactants are appropriately used. Due to the action of the surfactant, the fine particles that exist under the internal pressure of the υ system are uniformly dispersed. It's more cohesive, so it can fully demonstrate its performance.

Moreover, it becomes difficult to fall off from the composite fibrous material.

Fine fibrillated fibers are composited with the uranium-adsorbing organic polymeric material fine particles of the present invention using the above-mentioned fiber-forming polymeric material, uranium-adsorbing organic polymeric material fine particles, inorganic fine powder, surfactant, and solvent. The product is manufactured by the following method. In other words, it is difficult to dissolve the uranium-adsorbing organic polymer material, inorganic fine powder, fiber-forming polymer material, surfactant, and fiber-forming polymer material intimately mixed together at room temperature and pressure, but when heated or A mixture consisting of a relatively low-boiling point solvent that can be dissolved under increased pressure was heated and stirred under closed conditions to dissolve the fiber-forming polymeric material, and the uranium-adsorbing organic polymeric material particles and inorganic fine particles were uniformly dispersed. Further, a so-called flash spinning method is used in which the dispersion is rapidly discharged into a low pressure region of substantially atmospheric pressure through a nozzle under high temperature and high pressure. There is also an emulsion flash spinning method in which an aqueous solution is added to this dispersion polymer solution system to instantaneously form an oil-in-water or water-in-oil emulsion, and this is immediately similarly discharged from a nozzle into a low-pressure region under high temperature and high pressure. Can be used. In either case, instantaneous evaporation of the solvent in the low pressure region solidifies the fiber-forming polymeric material and forms fine fibrillated fibers. Furthermore, after preparing a polymer solution in which uranium-adsorbing organic polymer particles and inorganic fine particles are uniformly dispersed using a solvent that can dissolve the fiber-forming polymer substance under normal pressure, this is rapidly poured into a precipitating agent through a nozzle. A wet spinning method can also be used. In this method, the solvent is rapidly dissolved in the non-solvent of the polymer and removed.
At the same time, the non-solvent is mixed and dissolved into the polymer solution, leading to fiber formation. The solvent plays an important role in both methods in providing the desired structure during fiber formation.

In the method of the present invention, a uranium-adsorbing composite fibrous material can be further produced in the following manner.

That is, first, by using exactly the same method of compositing as for the uranium-adsorbing fine particles described above, organic polymeric substance fine particles capable of imparting lalan adsorption properties through uranium-adsorbing group introduction treatment are combined with fiber-forming polymeric substances to form an organic polymeric substance fine particle composite. Manufacture fibrous materials. Furthermore, by treating the composite fibrous material using the same method of introducing uranium adsorption groups as in the case of using the organic polymer material alone, the fine particles of the ρ organic polymer material in the composite fibrous material have uranium adsorption properties. can be applied to produce a uranium-adsorbing composite fibrous material.

<Examples> The present invention will be described in detail below, but these examples are not intended to limit the technical content of the present invention.

Example 1 Amidoxime resin (average particle size 18 μm, 10 mo1% triethylene glycol dimethacrylate as a crosslinking agent)
After copolymerizing with acrylonitrile using 0.3 mo1% of divinylbenzene and divinylbenzene, 100 parts by weight of the resin obtained by converting the IJ group into amidoxime and silica (Tokusil GU manufactured by Tokuyama Soda)
-N) 50 parts by weight in a pulverizer (ContraPlex
65C, manufactured by ALPINE) to intimately mix. This intimate mixture and polyethylene as a matrix polymer (Hl-Zex 2100J, manufactured by Mikata Petrochemical Co., Ltd.) 10
0 parts by weight, further [TPP1002A4 as a surfactant]
Salt (dodecylaminopropionic acid A/salt, bicyclization ■#
) was charged into an autoclave together with 1300 parts by weight of hexane, heated to 150-160°C with stirring, and held for 15 minutes. When flashed under pressure, a continuous fibrous composite of diamidoxime resin and silica was produced.As a result of scanning electron microscopy (SIHM) observation, silica was present on the surface of the amidoxime resin fine particles.

Uranium adsorption test: After immersing 50 mg of the above fibrous adsorbent in natural seawater (uranium content 12 μg) for 24 hours with stirring, uranium was desorbed with a 1N aqueous hydrochloric acid solution.
As determined by spectrophotometry, 3-5μg150m
g・24hr of uranium was extracted.

Example 2 Amidoxime resin (average particle size 18 μm, copolymerized with acrylonitrile using 10 mo 1% of triethylene glycol dimethacrylate and 2 mo 1% of divinylbenzene as crosslinking agents, and then converted into amidoxime of the nitrile group using hydroxylamine) 100 parts by weight of the resin) and 100 parts by weight of silica are intimately mixed in a pulverizer. This intimate mixture, 100 parts by weight of polyethylene, and 1 part of T P P 1002 A4 salt as a surfactant.
0 parts by weight were charged into an autoclave together with 1300 parts by weight of hexane, and spun in the same manner as in Example 1 to produce a continuous fibrous material. As a result of SEM observation, silica was present on the surface of the amidoxime resin fine particles.

Using this adsorbent, an adsorption test was conducted using 51 natural seawater in the same manner as in Example 1, and the result was 39μg/5.
0 mg/24hr of uranium was collected.

Example 6 Acrylonitrile (100 mo1%), lyethylene glycol dimethacrylate (10 mo1%), and divinylbenzene (2 mo1%) were dispersed in water using a surfactant and emulsion polymerization was performed to produce a copolymer with an average particle size of 10 μm. was manufactured. 100 parts by weight of this copolymer and 100 parts by weight of silica are intimately mixed using a pulverizer. This intimate mixture, 100 parts by weight of polyethylene, 10 parts by weight of T P P 1002Aj salt as a surfactant, and 1300 parts by weight of hexane were placed in an autoclave and spun in the same manner as in Example 1 to produce a continuous fibrous material.

This continuous fibrous material was treated with hydroxylamine.

Amidoxime groups were introduced to produce a uranium-adsorbing organic polymer fine particle composite fibrous material. S E li! As a result of observation, silica was present on the surface of the amidoxime resin fine particles.

Using this adsorbent, an adsorption test was conducted using K 5 t natural seawater as in Example 1.

6.2μg/50mg/24hr of uranium was collected.

Comparative Example 1 A fibrous material was produced in the same manner as in Example 1 except that the amidoxime resin and silica were not intimately mixed and were added to the autoclave separately, and a uranium adsorption test was conducted.2.
Only 3μg of uranium (150mg-24hr) was collected. As a result of SEM observation, the amidoxime resin fine particles and silica existed independently, and no silica was observed on the surface of the amidoxime resin fine particles.

<Effects of the Invention> As explained above, the uranium-adsorbing composite fibrous material of the present invention has uranium-adsorbing fine particles mixed in the fibers with good dispersion, so even when the fibers are cut or torn, the fine particles do not fall off. There is little leakage, and there is virtually no leakage. In addition, the composite uranium-adsorbing fine particles are closely mixed with fine silica,
Since the fiber is spun with its surface covered with silica, the area that comes into contact with the fiber-forming polymeric material that becomes the matrix decreases, and the surface that participates in uranium adsorption increases.

Furthermore, since the uranium-adsorbing fine particles are connected to the outside through fine voids, the exchange or diffusion of seawater is rapid.
Shows uranium adsorption speed comparable to that of uncomposite powder. Since the fine fibrillar fibers are made of a high molecular weight, fiber-forming polymer, they have remarkable durability against impact and abrasion, and completely protect the uranium-adsorbing fine particles they contain.

Claims (2)

[Claims] (1) A uranium-adsorbing composite fibrous material in which fine particles of a uranium-adsorbing, water-insoluble organic polymer material and fine inorganic powder are combined inside or near the surface of a fiber-forming polymer material with a fine fibrillar structure. 1. A method for producing a uranium-adsorbing composite fibrous material, which comprises closely mixing the uranium-adsorbing fine particles and the inorganic fine powder in advance. (2) Organic polymeric fine particles and inorganic fine powders, which are water-insoluble and can impart uranium adsorption properties through treatment to introduce uranium adsorbing groups, are combined inside or near the surface of a fiber-forming polymeric substance having a fine fibrillar structure. After that, when manufacturing a uranium-adsorbing composite fibrous material that imparts uranium adsorption properties to the organic polymeric material fine particles in the composite fibrous material by a uranium adsorption group introduction treatment, the organic polymeric material fine particles and the inorganic fine particles are combined. A method for producing a uranium-adsorbing composite fibrous material, the method comprising closely mixing the uranium-adsorbing composite fibrous material with a powder.