JP2015205229A - Cylindrical filter for cesium ion adsorption - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cylindrical cartridge filter which makes a cesium ion adsorbent fixed firmly and causes very little falling-off, has an excellent cesium ion adsorption capacity and combines the excellent cesium ion adsorption capacity and an ability of removing fine particles adsorbing cesium.SOLUTION: A cylindrical filter is laminated with nonwoven fabrics containing two or more fibers with a difference in melting point of 30°C or greater and/or a fiber consisting of polymers having a difference in melting point of 30°C or greater and located adjacently or being in the form of a sheath-core structure. At least one of the nonwoven fabrics is a nonwoven fabric fixed with a cationic polymer compound containing a tertiary or quaternary ammonium group, and other nonwoven fabrics are nonwoven fabrics fixed with a cationic polymer compound containing a tertiary or quaternary ammonium group and a cesium adsorbent.

Description

  The present invention relates to a cylindrical filter for adsorbing cesium ions, and more specifically, a cylindrical filter in which the cesium ion adsorbent is less removed, and has both excellent cesium ion adsorption performance and fine particle removal ability. It relates to filters.

  Conventionally, a cylindrical filter using fibers as a constituent component of a filtration layer is filtered by the filtration layer while the filtration target liquid is collected from the outermost periphery of the filtration layer formed in a hollow cylindrical shape to the center. It is configured to capture fine particles in the liquid.

Such cylindrical filters are widely used in various industries such as filtration of purified water in the pharmaceutical industry, electronics industry, etc., filtration of drinking water in the manufacturing process of drinking water, and filtration of coating agents in the automobile industry.

  As a cylindrical filter that has been used in the above fields, Patent Document 1 discloses that a staple fiber is opened with a card to form a web of a heat-adhesive composite fiber, and this web is wound while being heated to form a composite. A cylindrical filter thermally bonded with a low-melting-point component of fiber, Patent Document 2, describes a cylindrical filter prepared in the same manner as Patent Document 1 using a web obtained by a spunbond nonwoven fabric manufacturing method. These cylindrical filters use heat-adhesive conjugate fibers and have an advantage that stable capture accuracy can be obtained because separation between the heat-bonded fibers hardly occurs even when the filtration pressure is increased.

  Further, Patent Document 3 is obtained by heat-treating an ultrafine composite fiber web obtained by changing the fiber diameter while melt blow spinning and winding the wound core around the core, and then extracting the core. A cylindrical filter is described.

  Further, Patent Documents 4 to 6 disclose a sheet (for example, filter paper, membrane filter) having a desired hole diameter after heating a fiber assembly layer containing a heat-fusible conjugate fiber to a heat-fusing temperature, winding it around a core. Etc.) are wound together with the fiber assembly layer to form a microfiltration layer, and then the microfiltration tubular filter obtained by winding only the fiber assembly layer to form a pre-filtration layer and extracting the core after cooling is described. Has been.

JP-A-52-152575 JP-A-8-222604 JP-A-5-96110 Japanese Patent Publication No.56-49605 JP 2006-150222 A JP 2004-851 A

  However, these cylindrical filters are used for filtration of purified water used in the pharmaceutical industry and electronics industry, filtration in the production process of alcoholic beverages in the food industry, and filtration of coating agents in the automobile industry. It was not adsorbed. Furthermore, when these cylindrical filters are used for cesium ion adsorption, if the adsorbent that adsorbs radioactive cesium contained in the cylindrical filter at a high concentration falls off, it may cause further environmental pollution, which may be a serious situation. There was a problem with. In addition, in rivers in areas contaminated with radioactive cesium, cesium ions are not only dissolved in water, but may be adsorbed by fine particles such as sand. In addition to adsorbing, it is also necessary to adsorb fine particles such as sand. Therefore, a cylindrical filter having both excellent cesium ion adsorption performance and fine particle removal capability is required.

  An object of the present invention is to eliminate the above-mentioned problems, and the present invention is a cylindrical cartridge filter having an excellent cesium ion adsorption ability, which firmly adheres a cesium ion adsorbent and has very little dropout. The present invention provides a cylindrical cartridge filter having both excellent cesium ion adsorption ability and removal ability of fine particles adsorbed with cesium.

As a result of intensive studies to solve the above problems, the inventors of the present invention are excellent in cesium ion adsorption ability and very little loss of adsorbent by laminating a specific nonwoven fabric into a cylindrical filter. The present inventors have found that the present invention is a cesium ion-adsorbing cylindrical filter having a fine particle removing ability.
That is, the gist of the present invention is the following (1) to (4).
(1) It is a cylindrical filter in which two or more kinds of fibers having a melting point difference of 30 ° C. or higher and / or a non-woven fabric including fibers having a melting point difference of 30 ° C. or higher and fibers having an adjacent or core-sheath structure are laminated. And at least one of the non-woven fabrics is a non-woven fabric to which a cationic polymer compound containing a tertiary or quaternary ammonium group is fixed, and the other non-woven fabric is cationic containing a tertiary or quaternary ammonium group. A cylindrical filter for adsorbing cesium ions, comprising a non-woven fabric to which a polymer compound and a cesium ion adsorbent are fixed.
(2) The cylindrical filter for cesium ion adsorption according to (1), wherein the cesium ion adsorbent is a Prussian blue type complex.
(3) The two or more kinds of fibers having a melting point difference of 30 ° C. or higher and / or the fibers in which the polymer having a melting point difference of 30 ° C. or higher is adjacent or in a core-sheath structure are polyester fibers, polyamide fibers, The cylindrical filter for cesium ion adsorption according to (1) or (2), wherein the cylindrical filter is composed of one or more fibers selected from the group consisting of polyolefin fibers and polylactic acid fibers.
(4) Two or more types of fibers having a melting point difference of 30 ° C. or more and / or a low melting side fiber or polymer melting point of a fiber having a polymer having an adjacent or core-sheath structure with a melting point difference of 30 ° C. or more. Is a cylindrical filter for cesium ion adsorption according to any one of (1) to (3), wherein the temperature is 100 to 190 ° C.

  The cylindrical filter for cesium ion adsorption according to the present invention is a cylindrical filter in which a specific nonwoven fabric is laminated, and at least one of the nonwoven fabrics is fixed with a cationic polymer compound containing a tertiary or quaternary ammonium group. A non-woven fabric, and the other non-woven fabric includes a non-woven fabric to which a cationic polymer compound containing a tertiary or quaternary ammonium group and a cesium ion adsorbent are fixed. It is possible to provide a cylindrical filter for adsorbing cesium ions that has a very small amount of adsorbent falling off and also has a fine particle removing ability.

It is the schematic which shows an example of the heat processing press apparatus of the nonwoven fabric sheet used for this invention. It is the schematic which shows an example of the winding apparatus of the cylindrical filter used for this invention. It is the schematic which shows another example of the winding apparatus of the cylindrical filter used for this invention. It is this schematic which shows each diameter for the real volume calculation of the cylindrical filter used for this invention. It is this schematic which shows the cylindrical filter used for this invention.

  Details of the present invention will be described below.

  The cylindrical filter for adsorbing cesium ions of the present invention includes two or more types of fibers having a melting point difference of 30 ° C. or higher and / or fibers in which a polymer having a melting point difference of 30 ° C. or higher has an adjacent or core-sheath structure. It is necessary to consist of a nonwoven fabric.

  The combination of two or more kinds of fibers having a melting point difference of 30 ° C. or higher and / or fibers having a melting point difference of 30 ° C. or higher adjacent to each other or having a core-sheath structure is not particularly limited. Polyester fiber and polypropylene fiber, Polyamide fiber and polyethylene fiber, Polyamide fiber and polypropylene fiber, Polyethylene terephthalate fiber and polybutylene terephthalate fiber, Polyester fiber copolymerized with polyester fiber and low melting point, Nylon 6 fiber and Nylon 66 Fibers, thermoplastic fibers and natural fibers such as cellulosic fibers and animal fibers, thermoplastic fibers and activated carbon fibers, or fibers having a composite structure such as side-by-side, core-sheath structure, etc. 1 or 2 types of fiber Such as those above composite can be mentioned. In the present invention, as will be described later, a fiber having a low melting point or a fiber containing a polymer having a low melting point may be referred to as a heat-fusible fiber.

  The difference in melting point of 30 ° C. or more refers to the difference in melting point between two or more types of resins in the case of two or more fibers made of a single resin, and in the case of fibers having a composite structure made of resins having different melting points. The difference between the melting points of the different resins refers to the difference between the highest melting point and the lowest melting point in the case of a combination of fibers made of a single resin and / or a composite structure made of resins having different melting points.

  Mix two or more kinds of fibers having a melting point difference of 30 ° C. or more and / or fibers having a melting point difference of 30 ° C. or more adjacent to each other or a core-sheath structure, and heat to a predetermined heat fusion temperature described later. As a result, the fiber or polymer on the low melting point side softens and exhibits fusion properties, and the polymer on the high melting point side can retain its fiber structure as a non-fused portion.

  When the difference in melting point is less than 30 ° C., the temperature difference is small, and therefore, the low melting point fiber or the low melting point polymer is melted to retain the fiber structure when the low melting point polymer melts due to processing temperature fluctuations. However, since the contact area with the treated water containing cesium is reduced, the adsorptive capacity is lowered, which is not preferable.

  In the case of polyester fibers, polyamide fibers, polyolefin fibers, etc., from the viewpoint of fixing of the cesium adsorbent, the surface is treated with laser treatment, ultraviolet irradiation, plasma treatment, electron beam treatment, etc., hydroxyl groups, sulfate groups, etc. Those having the functional group are preferably introduced.

  The form of the fiber in which two or more kinds of fibers having a melting point difference of 30 ° C. or higher and / or a polymer having a melting point difference of 30 ° C. or higher in the present invention has an adjacent or core-sheath structure is not particularly limited. Examples thereof include short fibers, false twisted yarns, spun yarns, and slit yarns.

  Further, two or more types of fibers having a melting point difference of 30 ° C. or higher and / or a polymer having a melting point difference of 30 ° C. or higher and a fiber having a low melting point side or a polymer on a low melting point side of a fiber having an adjacent or core-sheath structure. The melting point of is preferably 110 to 190 ° C, more preferably 130 to 170 ° C. As will be described later, since it is necessary to perform heat treatment when fixing the cesium ion adsorbent to the fiber structure of the present invention, the melting point of the low melting point side fiber or the low melting point side polymer is set to 110 to 190 ° C. In the fixing heat treatment, the fiber structure can hold the form better, and the heat stability during storage in the roll form is higher and preferable.

  The nonwoven fabric of the present invention has two or more kinds of fibers having a melting point difference of 30 ° C. or more and / or fibers having a melting point difference of 30 ° C. or more and fibers having an adjacent or core-sheath structure dispersed almost uniformly. For example, a wet method or a dry method such as a card method, an airlaid method, a hydroentanglement method, or a needle punch method may be used, and a nonwoven fabric can be produced from a fiber web prepared by a known method. In addition, the short fiber nonwoven fabric comprised from a short fiber is preferable from the viewpoint of the high porosity of a sheet | seat from the objective of adsorb | sucking the cesium ion melt | dissolved in water.

  Mixing ratio of two or more kinds of fibers having a melting point difference of 30 ° C. or more and / or a fiber having a melting point difference of 30 ° C. or more and a fiber having a low melting point and a fiber having a low melting point adjacent to or in a core-sheath structure Is preferably 10% by mass or more, more preferably 10 to 90% by mass, and still more preferably 20 to 80% by mass in the total mass of all the constituent fibers constituting the nonwoven fabric. By setting the mixing ratio to 10% by mass or more, it is possible to better maintain the voids of the fiber structure during the fixing heat treatment of the cesium ion adsorbent, and further, when the fibers and the polymer on the low melting point side are dissolved. It is preferable because the gap of the fiber structure is blocked or the contact area with the treated water containing cesium ions is reduced, and the pressure loss of the cylindrical filter when the treated water is passed is kept low. . In addition, it is preferable because the cesium ion adsorbent can be prevented from falling off.

  Although the single fiber fineness of the fiber which comprises the nonwoven fabric used by this invention is not specifically limited, From a sticking viewpoint of a cesium ion adsorption agent, 3 dtex or less is preferable and 2 dtex or less is more preferable. By setting the fineness of the single fiber fineness to 3 dtex or less, the surface area including the voids in the nonwoven fabric is further improved, so that the amount of the cationic polymer compound to be described later increases, and as a result, the loading rate of the cesium ion adsorbent is increased. It is estimated that the fixing ability is improved because of the improvement.

The nonwoven fabric sheet used for the cylindrical filter of the present invention preferably has a thickness of 0.2 to 1.0 mm, more preferably 0.3 to 0.8 mm. The density of the nonwoven fabric sheet is preferably 0.1 to 0.5 g / cm ³ .

By setting the thickness of the non-woven fabric sheet to 0.2 to 1.0 mm, for example, in the manufacturing method described later, an appropriate tension can be applied when the non-woven fabric sheet is wound into a cylindrical shape. It is preferable because the tubular filter is uniformly dispersed and the step (outer diameter difference) at the cut portion wound into a cylindrical shape with a predetermined outer diameter is suppressed low. Furthermore, by setting the non-woven fabric sheet density to 0.1 to 0.5 g / cm ³ , the adsorption performance at the time of adsorbing cesium ions becomes moderate, and the pressure loss at the time of passing water is moderate. Therefore, it is preferable.

  The cylindrical filter of the present invention is a cylindrical filter in which the nonwoven fabrics are laminated, and at least one of the nonwoven fabrics is a nonwoven fabric to which a cationic polymer compound containing a tertiary or quaternary ammonium group is fixed. The other nonwoven fabric includes a nonwoven fabric to which a cationic polymer compound containing a tertiary or quaternary ammonium group and a cesium ion adsorbent are fixed. The nonwoven fabric to which a cationic polymer compound containing a tertiary or quaternary ammonium group is fixed is at least one of the nonwoven fabrics, and a cesium ion adsorbent is fixed from the viewpoint of effective supplementation of fine particles. None is preferred.

  The cationic polymer compound containing a tertiary or quaternary ammonium group is not particularly limited as long as it is a polymer compound containing a tertiary ammonium group or a quaternary ammonium group. As cationic polymer compounds containing tertiary amino groups, polymers of alkylaminoalkyl (meth) acrylamide, for example, polymers such as dimethyl or diethylaminoethyl (meth) acrylamide, dimethyl or diethylaminopropyl (meth) acrylamide, Dialkylaminoalkyl (meth) acrylate polymer, for example, dimethyl or diethylaminoethyl (meth) acrylate, polymer such as dimethyl or diethylaminopropyl (meth) acrylate, acrylamide / styrene copolymer, tertiary amino group-containing urethane system Examples thereof include polymers.

  Examples of the quaternary ammonium group-containing polymer include a polymer of (meth) acryloyloxyalkyltrialkylammonium salt, such as 2- (meth) acryloyloxyethyltrimethylammonium chloride, 3- (meth) acryloyloxy-2- Polymers of (meth) acrylamide alkyltrialkylammonium salts, such as polymers of hydroxypropyltrimethylammonium chloride, such as 3- (meth) acrylamidopropyltrimethylammonium chloride, 3- (meth) acryloylamino-2-hydroxypropyltrimethylammonium Polymers such as chloride, polymers of 2- (meth) acryloyloxyalkylbenzylammonium salt, such as 2- (meth) acryloyloxyethylbenzylammonium chloride, A polymer of (meth) acryloyloxyethyldimethylbenzylammonium chloride, a copolymer of the former two monomers and acrylamide, dimethylaminoethyl acrylate, acrylamidepropyldimethylbenzyl chloride and N, N-dimethylacrylamide and N -Methyl-N-benzylallylamine salt and N-methyl-N-hydroxyethylaminopropylacrylamide copolymer, etc., for example, dimethyl or diethyldiallylammonium chloride, β-vinyloxyethyl trialkylammonium salt, vinylbenzyl Examples thereof include polymers such as ammonium salts, and examples thereof include copolymers composed of these ammonium group-containing polymers and vinyl polymers.

  The cesium ion adsorbent of the present invention is not particularly limited as long as it adsorbs cesium ions, and examples thereof include a cesium ion adsorbing complex and zeolite. Examples of the cesium ion-adsorptive complex include Prussian blue complex and phthalocyanine complex.

Prussian blue-type complexes have the general formula _{A x M [Fe (CN)} 6] y · zH 2 O ( In the formula, A is a cation, M represents a metal atom) is a complex represented by. Examples of the cation for A include ammonium ions. The metal atom of M is a group consisting of vanadium, chromium, manganese, iron, ruthenium, cobalt, rhodium, nickel, palladium, platinum, copper, silver, zinc, lanthanum, europium, gadolinium, lutetium, barium, strontium, and calcium. One kind or two or more kinds of metal atoms selected from the above are exemplified. Among the combinations described above, Fe ₄ [Fe (CN) ₆ ] ₃ and FeNH ₄ [Fe (CN) ₆ ] are particularly preferable from the viewpoints of cesium ion adsorption ability and selectivity of cesium ions in the coexistence state of foreign substances. .

  The average primary particle size of the Prussian blue type complex is not particularly limited, but is preferably 0.001 to 100 μm, more preferably 0.001 to 10 μm, and further preferably 0.001 to 1 μm, from the viewpoints of cesium ion adsorption ability and processing suitability. Preferably, 0.001 to 0.05 μm is more preferable, and 0.001 to 0.02 μm is particularly preferable.

Examples of the phthalocyanine type complex include copper phthalocyanine, chlorinated copper phthalocyanine, brominated chlorinated copper phthalocyanine, and aluminum phthalocyanine. More specifically, examples of the copper phthalocyanine include Pigment Blue15, Pigment Blue15: 3, Pigment Blue76, Ingrain Blue1, and Direct Blue86. Examples of the chlorinated copper phthalocyanine include Pigment Green 7. As a brominated chlorinated copper phthalocyanine, Pigment Green 58 is exemplified.

  Zeolite is a general term for aluminosilicates having relatively large voids in the crystal structure and is not particularly limited, and examples thereof include crystalline aluminosilicates, metallosilicates, aluminophosphates, silicaaluminophosphates, and the like.

  The average primary particle diameter of zeolite is not particularly limited, but is preferably 0.1 to 100 μm, more preferably 1.0 to 50 μm, and still more preferably 1.0 to 30 μm, from the viewpoint of cesium ion adsorption ability and processing suitability.

  Since the cesium ion adsorbent is negatively charged as a whole, the cesium ion adsorbent has a high concentration by being fixed to a non-woven fabric treated with the cationic polymer compound containing the tertiary or quaternary ammonium group. It is presumed that it can be adsorbed to the nonwoven fabric sheet.

  The cylindrical filter according to the present invention includes at least one non-woven fabric to which the cationic polymer compound containing a tertiary or quaternary ammonium group is fixed, and a cationic high polymer containing a tertiary or quaternary ammonium group. It can be prepared by laminating the non-woven fabric to which the molecular compound and the cesium ion adsorbent are fixed, performing heat treatment as necessary, and then forming a cylinder by a method described later.

  The cylindrical filter in the present invention is a cylindrical filter made of the above-mentioned non-woven fabric, and the cesium ions are collected while the cesium ion-containing treated water is collected from the outermost peripheral portion of the filtration layer formed into a cylindrical shape by pressure filtration to the central portion. For example, it can be used by being set in a pressure vessel (housing).

The cylindrical filter according to the present invention has a breakthrough point of 1000 L or more when a cesium chloride aqueous solution having a cesium ion concentration of 0.1 ppm is passed through under the condition that the superficial velocity SV indicated by the following formula (1) is 10. preferable.
Superficial velocity (Hr ⁻¹ ) = flow rate of filtered water (m ³ / Hr) / actual volume of cylindrical filter (m ³ ) (1)

  The superficial velocity (SV) is expressed as the reciprocal of the time for which the filtered water contacts the filtration layer per unit time, and the filtered water corresponding to how many times the volume of the filter medium is processed per unit time. As described above, it can be obtained by dividing the flow rate of water to be filtered per unit time by the amount (volume) of the filter medium.

The breakthrough point represents the adsorption ability of the adsorbate of the cylindrical filter. In the present invention, when water is passed through the container equipped with the cesium ion adsorption cylindrical filter at the superficial velocity SV. A breakthrough curve in which the ratio of the cesium ion concentration C on the outlet side to the cesium ion concentration C ₀ on the inlet side (C / C ₀ ) with respect to the water flow rate (L) on the X-axis is prepared, and (C / The amount of water flow (L) at which C ₀ ) = 0.05.

In the above description, the larger the breakthrough point at the same superficial velocity, the higher the superficial velocity at the same breakthrough point, the higher the adsorption capacity. In the present invention, when the superficial velocity at which the aforementioned C / C ₀ (ratio of the cesium ion concentration C on the outlet side to the cesium ion concentration C ₀ on the inlet side) is 0.05 is less than 10, the water to be filtered It takes a lot of time to process the process, which increases the processing cost.

  The falling rate of the cesium ion adsorbent from the cylindrical filter in the present invention is preferably 2 ppm or less, more preferably 1 ppm or less, and even more preferably 0.5 ppm or less. In the present invention, at least one of the nonwoven fabrics constituting the cylindrical filter is a nonwoven fabric to which a cationic polymer compound containing a tertiary or quaternary ammonium group is fixed. Not only is the amount of falling off very small, but negatively charged fine particles adsorbed by cesium ions dropped into water can be adsorbed and removed again. A cylindrical filter for adsorbing cesium ions that has very little dropout and has the ability to remove fine particles can prevent the secondary contamination of the adsorbed radioactive cesium from flowing out and diffusing into the environment.

Cylindrical filter density of the present invention is preferably 0.15~0.5g / cm ^3, more preferably 0.2~0.45g / cm ^3, 0.25~0.45g / More preferred is cm ³ . By setting the density to 0.15 to 0.5 g / cm ³ , the amount of filter necessary for adsorbing cesium ions and the pressure loss during filtration become appropriate.

  The content of the cesium ion adsorbent in the cylindrical filter of the present invention is preferably 0.5% by mass or more, more preferably 0.8% by mass or more, and 1.0% by mass or more from the viewpoint of cesium ion adsorption performance. Even more preferable. Further, although depending on the size of the cylindrical filter and the designed superficial velocity, the amount of cesium ion adsorbent contained in the cylindrical filter is preferably 0.8 g or more, from the viewpoint of cesium ion adsorption performance, 1.2 g The above is preferable, and 1.5 g or more is more preferable. By setting the content to 0.5% by mass or more and / or the content to 0.8g or more, the adsorption ability of cesium ions becomes sufficient, so the cylindrical filter of the present invention is applied to various filter media. It can be used suitably.

  In the cylindrical filter of the present invention, the density, thickness, etc. of the filter are optimized by appropriately selecting conditions such as the basis weight of the nonwoven fabric sheet, the temperature during the fusion treatment of the low melting point fiber, the pressing pressure, and the gap. Can be

  Below, the manufacturing method of the cylindrical filter for cesium ion adsorption | suction of this invention is demonstrated.

  In the method for producing a cylindrical filter of the present invention, two or more kinds of fibers having a melting point difference of 30 ° C. or higher and / or fibers having a melting point difference of 30 ° C. or more and adjacent or core-sheath fibers are mixed. The nonwoven fabric is formed by a known fiber web creation method such as the card method, airlaid method, hydroentanglement method, needle punch method, or the like.

  If necessary, for example, a nonwoven sheet having a predetermined thickness, density, etc. can be obtained by subjecting the obtained nonwoven fabric to a hot press treatment using, for example, a net dryer provided with two hot press rolls as shown in FIG. It can also be.

  Next, the obtained nonwoven fabric sheet is first subjected to cationization treatment with a cationic polymer compound containing a tertiary or quaternary ammonium group, thereby creating a nonwoven fabric to which the cationic polymer compound is fixed. Examples of the method for treating the cationic polymer compound include an exhaust method, a pad (spray, print) -steam method, a pad (spray, print) -heat treatment method, and the like, which is appropriately selected depending on the form of the cylindrical filter. However, the exhaust method, pad (spray, print) -steam method, pad (spray, print) -heat treatment method are preferred, and from the viewpoint of their strong adhesion, pad (spray, print) -steam method, pad (Spray, print)-A heat treatment method is more preferred.

  When the exhaust method is employed, the exhaust temperature and exhaust time are preferably 3 to 60 minutes if they are 20 to 100 ° C, and more preferably 20 to 60 minutes if they are 40 to 80 ° C.

  When the pad (spray, print) -steam method or the pad (spray, print) -heat treatment method is employed, the heat treatment is preferably performed at a temperature of 130 to 220 ° C. In addition to the physical and ionic interaction between the polymer constituting the nonwoven fabric and the cationic polymer compound, by performing heat treatment at the temperature, the low melting point component softens or melts and exhibits heat-fusibility, A coating of a cationic polymer compound can be formed on the surface of the fiber constituting the nonwoven fabric.

  When the heat treatment temperature is less than 130 ° C., the film formation of the cationic polymer compound becomes insufficient. When the heat treatment temperature exceeds 220 ° C., the heat-fusible fiber melts rapidly, and a uniform film formation cannot be achieved. Since it becomes difficult to process in the next step by curing, it is not preferable.

  The heat treatment time can be appropriately selected according to the basis weight of the sheet, but it is preferable that the heat treatment time is longer as the basis weight is larger from the viewpoint of uniform film formation.

  The fixed amount of the cationic polymer compound of the present invention is preferably 0.1 to 10% by mass with respect to the fiber material constituting the nonwoven fabric, from the viewpoint of cesium ion adsorption performance and reduction of cesium ion adsorbent dropout. 1-5 mass% is more preferable. In order to improve the permeability of the cationic polymer compound into the nonwoven fabric, it is preferable to use a nonionic or cationic surfactant in combination with the bath solution.

  After carrying out the cationization treatment of the present invention, the non-fixed cationic polymer compound is washed with water or / and warm water, and if necessary, dried and then fixed with the cesium ion adsorbent. It is preferable to perform the treatment from the viewpoint of reducing the dropout of the agent.

  Subsequently, the cationic polymer compound containing a tertiary or quaternary ammonium group and the cesium ion adsorbent were fixed by carrying out the fixing treatment of the cesium ion adsorbent on the cationized non-woven fabric. A nonwoven fabric can be created. Here, one or more resins selected from the group consisting of polyester resins, acrylic resins, vinyl acetate resins, polyurethane resins, and silicon resins can be used in combination. The fixing treatment method can be appropriately selected from known methods such as the exhaustion method, pad (spray, print) -steam method, pad (spray, print) -heat treatment method, as in the cationization treatment.

  When the exhaust method is adopted, the exhaust temperature and exhaust time are preferably 3 to 60 minutes at 20 to 100 ° C., and 20 to 60 at 40 to 80 ° C., as in the cationization treatment. Minutes are more preferred.

  When the pad (spray, print) -steam method or the pad (spray, print) -heat treatment method is employed, the heat treatment is preferably performed at a temperature of 130 to 220 ° C.

  In the present invention, at least one nonwoven fabric to which the cationic polymer compound containing a tertiary or quaternary ammonium group is fixed, a cationic polymer compound containing a tertiary or quaternary ammonium group, and After laminating the nonwoven fabric to which the cesium ion adsorbent is fixed, and performing heat treatment as necessary, it can be formed into a cylinder by the method described later.

  Lamination in the present invention refers to a form in which the above two or more types of non-woven fabric are contained in a cylindrical filter, and a non-woven fabric having a cationic polymer compound fixed to the inner layer of the core as shown in FIG. Non-woven fabric with a cationic polymer compound and a cesium ion adsorbent fixed on the outer layer, or a cylindrical shape, or a configuration in which the inner and outer layers are reversed, and different non-woven fabrics are stacked alternately Etc. Among these, from the viewpoint of suppressing cesium ion adsorbent dropout and improving the performance of removing fine particles, a form in which different nonwoven fabrics are alternately laminated is preferable.

  The cylindrical filter of the present invention is formed by winding the above-mentioned two or more types of non-woven fabric around a pipe of a predetermined diameter to form a cylindrical shape, and then winding and fixing the outermost package with a release paper or a release film. Heat treatment is performed at a temperature of 130 to 220 ° C. using a heat treatment furnace. The pipe to be used is preferably one in which the pipe surface is subjected to mold release treatment with polytetrafluoroethylene, silicon, or the like, from the viewpoint of pipe pullability after heat treatment, etc.

  If the said heat processing temperature is less than 130 degreeC, the fusion | melting of a heat sealing | fusion fiber will become inadequate and it may become difficult to shape | mold into a cylinder shape. On the other hand, if the heat treatment temperature exceeds 220 ° C., the heat-sealing fiber melts rapidly, so that a uniform coating cannot be formed, and the pores of the filter become too small, so that the pressure loss at the time of passing water becomes high. The heat treatment time can be appropriately selected depending on the outer diameter of the cylinder, but may be performed in the range of 10 to 120 minutes, for example.

  After the above heat treatment, after cooling to room temperature, the pipe is pulled out and cut into a predetermined size, whereby a cesium ion adsorption cylindrical filter can be obtained.

  As a specific example of the present invention, a cylindrical cartridge filter in which a non-woven fabric with a cationic polymer compound fixed to the inner layer of the core is arranged and a non-woven fabric with a cationic polymer compound and a cesium ion adsorbent fixed to the outer layer is arranged. Is obtained by winding a non-woven fabric having a cationic polymer compound fixed on a pipe having a predetermined diameter into a cylindrical shape, and further stacking a non-woven fabric for adsorption of cesium ions to form a cylindrical tube shape through the above-described steps. In addition, the cylindrical filter in which the nonwoven fabrics are alternately laminated has a predetermined diameter of the nonwoven fabric to which the cationic polymer compound is fixed and the nonwoven fabric to which the cationic polymer compound and the cesium ion adsorbent are fixed as shown in FIG. It is obtained by going through the above-mentioned process as a cylindrical shape by winding it around a pipe.

  Next, the present invention will be specifically described with reference to examples. In addition, this invention is not limited to the Example shown below.

  The evaluation method of the cylindrical filter for cesium ion adsorption | suction of this invention in an Example and a comparative example is as follows.

1. Thickness of nonwoven fabric sheet JIS L 1913: 2010 General nonwoven fabric test method It measured by the method of thickness (6.1) description.

2. Density of nonwoven fabric sheet Using the thickness and basis weight of the nonwoven fabric sheet, the density was calculated by the following formula (2).
Non-woven sheet density (g / cm ³ ) = (weight per unit area (g / cm ² ) / thickness (mm)) × 10 ⁻³ (2)

3. Density of cylindrical filter
The volume of the tubular filter was determined from the thickness of the tubular filter, and the volume was calculated by the following formula (3) using the density and mass of the nonwoven fabric sheet.
P = M / V (3)
P: cylindrical filter density (g / cm ³ )
M: Mass of the cylindrical filter (g)
V: Actual volume of the cylindrical filter (cm ³ )
In addition, the actual volume of the cylindrical filter was made into the volume (refer FIG. 4) which remove | excluded the volume of the core pipe part from the whole volume of the cylindrical filter from following formula (4).
Actual volume of cylindrical filter = (π (D1 / 2) ² −π (D2 / 2) ² ) × L (4)

4). Loading rate (%) and loading amount (g) of cesium ion adsorbent in cylindrical filter
The non-woven fabric to which the cesium ion adsorbent is fixed is incinerated at 600 ° C. for 30 minutes, and then completely dissolved in aqua regia. The amount of iron in the aqueous solution is determined by ICP emission spectroscopic analysis, and per unit mass of the cylindrical filter. The carrying amount (g) of the cesium ion-adsorbing complex was obtained from the mass of the cylindrical filter and the carrying rate. In Examples and Comparative Examples, the conversion of the cesium ion adsorbent from the iron amount was performed based on the following molecular formula 1.
Fe ₄ [Fe (CN) ₆ ] ₃ ... (molecular formula 1)
Supported amount of cesium ion adsorbent (g) = [(supported cesium ion adsorbent (g) / tubular filter amount (g)) × 100] × tubular filter mass (g) (5)

5. Evaluation of adsorption amount of cesium ions by water flow through cylindrical filter Seal both ends of cylindrical filter with sealant material (Shin-Etsu Chemical Co., Ltd., trade name: Shin-Etsu Sealant KE-45-W), then set in plastic housing Then, a cesium chloride aqueous solution adjusted to a cesium ion concentration of 0.1 ppm was passed through the metering pump at a superficial velocity SV10 (Hr ⁻¹ ), and the cesium ion concentration on the outlet side with respect to the cesium ion concentration (C ₀ ) on the inlet side Plot the C ratio (C / C ₀ ) on the Y-axis and the water flow rate (L) on the X-axis to create a breakthrough curve, and use (C / C ₀ ) = 0.05 as the breakthrough point. Asked. The cesium ion concentration was quantified by ICP-MS (measured according to JIS K 01025.5 (2008) and JIS K 0133 (2000)).

6). Prussian blue dropout evaluation from cartridge The treatment liquid was sampled 1 minute after passing water when evaluating the adsorption amount of cesium ions of the above cylindrical filter, and the amount of cyanide compound in the treatment liquid was determined according to JIS K0102 38.1.2 and 38.3 ( (2008) and the amount of adsorbed cesium ion adsorbed (ppm) was calculated based on molecular formula 1 described above.

7). Fine particle removability evaluation JIS S 3201: 2010 Household water purifier test method 6.4.2 Evaluation was performed based on the turbidity removability test. At that time, sample water in which standard kaolin having an average particle diameter of 7 μm was adjusted to a turbidity of 2 ± 0.2 degrees was used. In addition, if 10% or more of kaolin particles having an average particle diameter of 7 μm in the sample water can be removed, it indicates that sand, adsorbent and the like adsorbing cesium ions can be effectively removed.

Example 1
<Creation of non-woven sheet>
As the low melting point fiber, a core-sheath composite fiber (trade name “Melty 4080” manufactured by Unitika Ltd.) having a core component of polyethylene terephthalate (melting point 255 ° C.) and a sheath component of copolymer polyethylene terephthalate (melting point 110 ° C.), a fineness of 2. 2 dtex, fiber length 51 mm) 75% by mass, polyethylene terephthalate single fiber (trade name “Unitika Ester” manufactured by Unitika Ltd., melting point 255 ° C., fineness 2.2 dtex, fiber length 51 mm) 25% by mass as high melting point fiber Uniform blending was made into a parallel card web. The web was laminated by a known method using a cross wrapper, and was subjected to needle punching after drafting with a drafter to obtain a nonwoven fabric having a basis weight of 80 g / m ² and a width of 120 cm. Next, the nonwoven fabric was heated at a heat treatment zone temperature of 140 ° C., a hot press roll temperature of 90 ° C., a speed of 3 m / min, in a heat treatment machine shown in FIG. Press processing was performed under the conditions of a pressure of 3 MPa and a gap between two press rolls of 0.3 mm to obtain a nonwoven fabric A having a thickness of 0.3 mm and a density of 0.27 g / cm ³ .

<Cationization treatment / Adhesive heat treatment for adsorbent>
Next, the obtained non-woven fabric is padded with an aqueous solution having the following prescription 1, squeezed with a mangle so that the wet pickup becomes 100% by mass, and dried and heat-treated with a pin tenter at 150 ° C. for 4 minutes. A cationized nonwoven fabric B was obtained. Next, the nonwoven fabric B was subjected to padding treatment with a dispersion liquid having the following prescription 2, wrung with a mangle so that the wet pickup would be 100% by mass, and fixed with a Prussian blue type complex at 150 ° C. for 4 minutes with a pin tenter. Heat treatment was performed to obtain a nonwoven fabric C to which the cationic polymer compound of the present invention having a thickness of 0.5 mm and a density of 0.16 g / cm ³ and a cesium ion adsorbent were fixed.
(Prescription 1)
Cationic polymer compound (Cationizing agent CT F1101 manufactured by Sanyo Dyeing Co., Ltd.) 20 g / l
Nonionic surfactant (Actinol R100 manufactured by Matsumoto Yushi Seiyaku Co., Ltd.) 2g / l
(Prescription 2)
Prussian blue (Fe ₄ [Fe (CN) ₆ ] ₃ manufactured by Kanto Chemical Co., Ltd., hydrophobic / low purity solid content 11%, average primary particle size 0.01 μm) 100 g / l
Acrylic binder (NK binder A-12HN, solid content 45% by mass, manufactured by Shin-Nakamura Chemical Co., Ltd.) 100 g / l
Nonionic surfactant (Actinol R100 manufactured by Matsumoto Yushi Seiyaku Co., Ltd.) 2g / l

<Creation of cylindrical filter for cesium ion adsorption>
Using a two-roll winder shown in FIG. 2, first, a non-woven fabric B set with a cationization treatment is set on the non-woven fabric feed-out portion 7 and wound on a pipe 12 having an outer diameter of 30 mm and treated with polytetrafluoroethylene by a length of 0.5 m. Subsequently, the non-woven fabric feeding portion 7 is replaced with the non-woven fabric C to which the cationic polymer compound and the cesium ion adsorbent are fixed, and the outer diameter is wound up by 5.5 m to an outer diameter of 65 mm. A winding roll was used. Subsequently, the winding roll was heat-treated at a temperature of 160 ° C. for 60 minutes with a box-type heat treatment machine, cooled, then pulled out of a pipe, cut into a length of 250 mm with a round blade cutting machine, and a density of 0.21 g / cm ³ , A cylindrical filter for cesium ion adsorption according to the present invention containing 1.47 g of cesium ion adsorbent was obtained.

Example 2
The non-woven fabric feeding unit 7 is a non-woven fabric feeding unit 7 in which the cationized non-woven fabric B, the cationic polymer compound and the cesium ion adsorbent used in Example 1 are fixed to the non-woven fabric feeding unit 7 of the two-roll winder shown in FIG. The non-woven fabric B and the non-woven fabric C were simultaneously wound up by 3 m each to have the same outer diameter of 65 mm as in Example 1, and a cylindrical filter for cesium ion adsorption having the same dimensions as in Example 1 was obtained. The innermost layer was the non-woven fabric B subjected to the cationization treatment. The obtained cylindrical filter for cesium ion adsorption had a density of 0.21 g / cm ³ and contained 0.78 g of a cesium ion adsorbent.

Example 3
A cylindrical filter for cesium ion adsorption according to the present invention was obtained in the same manner as in Example 1 except that the formulation 1 of Example 1 was changed to the following formulation 3.
(Prescription 3)
Cationic polymer compound (Cationizing agent CT F1101 manufactured by Sanyo Dyeing Co., Ltd.) 60 g / l
Nonionic surfactant (Actinol R100 manufactured by Matsumoto Yushi Seiyaku Co., Ltd.) 2g / l

Comparative Example 1
The cesium ion adsorbent was used in the same manner as in Example 1 except that the non-woven fabric B subjected to the cationization treatment was used and only the non-woven fabric C to which the cationic polymer compound and the cesium ion adsorbent were fixed was wound up to 6 m. A cylindrical filter for adsorption of cesium ions containing 1.6 g of was obtained.

Comparative Example 2
A comparative cesium ion adsorption cylindrical filter was obtained in the same manner as in Example 1 except that the non-cationized non-woven fabric B was changed to non-cationized non-woven fabric A.

Comparative Example 3
A comparative cesium ion adsorption cylindrical filter was obtained in the same manner as in Example 2 except that the non-cationized non-woven fabric B was changed to non-cationized non-woven fabric A.

Comparative Example 4
Except for changing the non-woven fabric C to which the cationic polymer compound and the cesium ion adsorbent of Example 1 were fixed to the non-woven fabric D to which the cesium ion adsorbent was fixed under the same conditions without applying the cationic polymer compound. In the same manner as in Example 1, a comparative cesium ion adsorption cylindrical filter was obtained.

Comparative Example 5
The non-cationized non-woven fabric A of Example 1 was changed to non-cationized non-woven fabric A, and the same conditions were applied to the non-woven fabric C to which the cationic polymer compound and the cesium ion adsorbent were fixed without applying the cationic polymer compound. A comparative cesium ion adsorption cylindrical filter was obtained in the same manner as in Example 1 except that the non-woven fabric D was fixed with the cesium ion adsorbent.

  As is apparent from Table 1, the cylindrical filters for cesium ion adsorption of Examples 1 to 3 of the present invention are the non-woven fabric to which the cationic polymer compound is fixed, the cationic polymer compound and the cesium ion adsorbent. Thus, the cesium ion-adsorbing cylindrical filter was excellent in cesium ion adsorption capacity, had very little detachment of the adsorbent, and had particulate removal ability. In particular, the tubular filter of Example 2 in which the nonwoven fabric to which the cationic polymer compound is fixed and the nonwoven fabric to which the cationic polymer compound and the cesium ion adsorbent are alternately laminated is the suppression of cesium ion adsorbent falling off. And the removal performance of fine particles was extremely high. On the other hand, since the cylindrical filters of Comparative Examples 1 to 3 did not include the nonwoven fabric to which the cationic polymer compound was fixed, the cesium ion adsorption ability and the adsorbent dropout inhibition ability were more than a certain level, but the particulate removal The ability was low. The cylindrical filters of Comparative Examples 4 and 5 did not use a non-woven fabric in which a cationic polymer compound was fixed to either or both non-woven fabrics. Therefore, the ability of the cesium ion adsorbent to fall off and the ability to remove fine particles were low. .

DESCRIPTION OF SYMBOLS 1 Nonwoven fabric roll delivery part 2 Nonwoven fabric 3 Heat treatment zone part 4 Net 5 Hot press roll 6 Winding part of press-processed nonwoven fabric 7 Nonwoven fabric delivery part 8 Nonwoven fabric to which cationic polymer compound and / or cesium ion adsorbent is fixed 9 Guide roll DESCRIPTION OF SYMBOLS 10 Cartridge winding 2 roll 11 Cylindrical cartridge roll 12 Pipe 13 Presser roll 14 Cartridge roll preparation zone 15 The nonwoven fabric winding layer to which the cationic polymer compound was adhered

Claims (4)

A tubular filter in which two or more kinds of fibers having a melting point difference of 30 ° C. or higher and / or a nonwoven fabric containing fibers in which a polymer having a melting point difference of 30 ° C. or higher is adjacent or a core-sheath structure is laminated, At least one of the nonwoven fabrics is a nonwoven fabric to which a cationic polymer compound containing a tertiary or quaternary ammonium group is fixed, and the other nonwoven fabric is a cationic polymer compound containing a tertiary or quaternary ammonium group And a cylindrical filter for adsorbing cesium ions, comprising a nonwoven fabric to which a cesium ion adsorbent is fixed. The cylindrical filter for cesium ion adsorption according to claim 1, wherein the cesium ion adsorbent is a Prussian blue type complex. The two or more types of fibers having a melting point difference of 30 ° C. or higher and / or the fibers having a core-sheath structure adjacent to the polymer having a melting point difference of 30 ° C. or higher are polyester fiber, polyamide fiber, polyolefin fiber The cylindrical filter for cesium ion adsorption according to claim 1 or 2, wherein the cylindrical filter is composed of one or more fibers selected from the group consisting of polylactic acid fibers. The melting point of the fiber or polymer on the low melting point side of the fiber having a melting point difference of 30 ° C. or more and / or a fiber having a melting point difference of 30 ° C. or more adjacent to or in a core-sheath structure is 100 It is -190 degreeC, The cylindrical filter for cesium ion adsorption | suction of any one of Claims 1-3 characterized by the above-mentioned.