JP2007007575A - Microorganism carrier and its production method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a microorganism carrier in which a side chain is introduced into a composite fiber substrate to make the side chain contain an anion-exchange group. <P>SOLUTION: The microorganism carrier including a composite fiber in which the side chain is introduced into the composite fiber substrate by radiation graft polymerization has the anion-exchange group on the side chain. The method for producing the microorganism carrier comprises a process for irradiating the composite fiber substrate including the composite fiber having a core and case structure with radiation, a process for impregnating the substrate with a polymeric monomer and a process for graft-polymerizing the substrate with the monomer. By using the microorganism carrier, a larger amount of microorganisms can efficiently be carried while maintaining an advantage inherent in the composite fiber substrate. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a microorganism carrier for supporting microorganisms and a method for producing the same. In particular, the present invention relates to a microbial carrier used to treat liquids in water treatment or industrial processes.

  Biological treatment methods using microorganisms and the like are known as water treatment methods for water and wastewater to reduce biological contamination. Conventionally, the activated sludge method has been the mainstream biological treatment. there were. However, this activated sludge method requires not only solid-liquid separation between the microorganisms constituting the sludge and water, but also the control is complicated.

  Therefore, recently, biological treatment using immobilized microorganisms which are easier to control and have a higher treatment capacity has been performed. The treatment method using immobilized microorganisms is a method in which water treatment is performed by adsorbing microorganisms on a carrier to form immobilized microorganisms and contacting or passing water to be treated with the immobilized microorganisms. In the treatment method using immobilized microorganisms, a material having a large specific surface area (for example, sand or activated carbon which is a filler for filtration tanks generally used in water treatment) is preferably used as a microorganism-immobilized support. It has been proposed to use a porous material such as a sponge, a porous film, a fiber assembly such as a woven fabric or a non-woven fabric as a large material. In particular, a fiber assembly such as a woven fabric or a non-woven fabric has (1) a large porosity and a large amount of microorganisms supported, and (2) simultaneous contact with microorganisms to be treated and removal of particles in the objects to be treated. In addition, (3) it is easy to mold (for example, it can be wound into a cylinder to form a laminated structure, pleated or bag-like), etc. Often used.

Such a fiber assembly is further functionalized by a chemical method and used as a microorganism adsorbing material. For example, by imparting a chemical functional group, the fiber surface is positively charged, and negatively charged microorganisms are effectively adsorbed on the fiber (for example, Patent Document 1). Based on such a principle, for example, in Patent Document 2, a nonwoven fabric having a pyridine group as a quaternary ammonium group is synthesized and used for microorganism adsorption. In Patent Document 3, vinyl pyridine is graft copolymerized with an insoluble polymer, and the pyridine group is used as a quaternary ammonium group as a microorganism adsorbent.
Japanese Unexamined Patent Publication No. Sho 63-31538 JP-A-4-11949 JP-A-4-164035 [Problems to be Solved by the Invention]

  However, in the microbial carrier described in Patent Document 2, it is necessary to reduce the number of pyridine groups so as not to be water-soluble, and in order to obtain a stable fiber form, mixing with another fiber-forming resin is necessary. It is considered that the density of the substantial quaternary ammonium group is reduced. In addition, in the microbial carrier described in Patent Document 3, a polymer base material having a hydroxyl group is preferably used, and is preferably produced by a method using a redox type polymerization initiator. There is no mention of application to polymer substrates having a chemically inert surface.

In view of such circumstances, the present invention has been devised for the purpose of solving the above-mentioned problems. That is, the object of the present invention is to support a larger amount of microorganisms while maintaining the advantages of the composite fiber base material such as a high porosity and surface area, easy molding, and high physical strength. It is to provide a microorganism carrier.
[Means for solving the problems]

The present invention includes a microbial carrier having the following characteristics and a method for producing the same.
(1) A microbial carrier comprising a composite fiber in which a side chain is introduced into a composite fiber base material by radiation graft polymerization, wherein the side chain has an anion exchange group.
(2) The microbial carrier according to (1), wherein the composite fiber substrate comprises fibers having a core-sheath structure.
(3) The microbial carrier according to (1) or (2), wherein the anion exchange group of the side chain has an ion exchange capacity of 0.5 meq / g or more.
(4) The anion exchange group is one or more selected from a primary amino group, a secondary amino group, a tertiary amino group, and a quaternary ammonium group, of (1) to (3) The microbial carrier according to any one of the above.
(5) The microbial carrier according to any one of (1) to (4), wherein the composite fiber base material is a fiber assembly.
(6) The microbial carrier according to (5), wherein the fiber assembly is a woven fabric or a nonwoven fabric.
(6) a step of irradiating a composite fiber base material including a composite fiber having a core-sheath structure; a step of impregnating the base material with a polymerizable monomer; and a step of graft polymerization of the monomer onto the base material; A method for producing a microbial carrier comprising:

  From one aspect, the present invention is a microbial carrier comprising a composite fiber in which a side chain is introduced into a composite fiber base material by radiation graft polymerization, wherein the side chain has an anion exchange group. .

Radiation Graft Polymerization The microbial carrier of the present invention comprises a composite fiber having side chains introduced into a composite fiber base material by radiation graft polymerization. In the present invention, the radiation graft polymerization is a polymerization method in which a base material is irradiated with radiation, and is a polymerization method in which a monomer (monomer) is polymerized from a polymerization start point on the base material and side chains are introduced. is there. In general, in radiation graft polymerization, radicals are generated on a substrate by irradiation with radiation, polymerization is started based on the radicals, and graft side chains are introduced into the substrate. Therefore, according to radiation graft polymerization, a graft side chain having various functional groups can be introduced even on a substrate that does not have a functional group such as a hydroxyl group (hydroxy group) on the surface such as polyolefin, Various chemical modifications can be performed on the substrate.

  In particular, in radiation graft polymerization, conditions such as the type of radiation, irradiation dose, and irradiation time can be adjusted to generate radicals up to the inside of the substrate. In the present invention, by utilizing radiation graft polymerization, radicals can be generated even inside the fiber as the base material, and the graft side chain can be introduced into the fiber. The amount (density) of anion exchange groups) can be increased. Depending on the type of microorganisms supported on the carrier, when the target substance of microorganisms interacts with a functional group (anion exchange group) introduced into the microorganism carrier, adsorption of the target substance occurs inside the microorganism carrier. Therefore, the process by microorganisms is performed efficiently. This is particularly effective when removing relatively low concentrations of contaminants. Thus, the extremely superior effect of the present invention can be obtained by using radiation graft polymerization.

  Examples of the radiation that can be used in the present invention include high-energy radiation such as γ-rays, electron beams, β-rays, α-rays, ultraviolet rays, X-rays, and neutrons, with γ-rays and electron beams being preferred. The irradiation amount is preferably 20 to 300 kGy. If it is less than 20 kGy, sufficient radicals are not generated, and if it exceeds 300 kGy, problems such as increased radiation degradation occur.

  In addition, radiation graft polymerization includes “simultaneous irradiation graft polymerization method” in which a substrate and a monomer coexist at the time of radiation irradiation, and “pre-irradiation grafting in which the substrate and the polymerizable monomer are contacted after the substrate is irradiated with radiation in advance. A "polymerization method" is known, but either method can be used in the present invention. In the present invention, either method can be used depending on the application. For example, the pre-irradiation graft polymerization method is suitable for performing high-level treatment because the amount of homopolymer is small. Here, the homopolymer means a polymer of a monomer that has not been used for graft polymerization, and may be eluted in a washing step or a treatment step. In addition, the advanced treatment is often installed in the subsequent stage of the steps such as [aggregation precipitation-filtration] and [biological treatment-precipitation-filtration] that are usually employed in water treatment, for example, activated carbon treatment, etc. As an example.

  Further, depending on the contact method between the substrate and the monomer, “liquid phase graft polymerization”, “gas phase graft polymerization”, “impregnation gas phase graft polymerization”, etc. are known as graft polymerization. It can be used in the invention. In particular, the impregnated gas phase graft polymerization method is a method of impregnating a base material into a monomer and supporting the monomer on the base material to perform graft polymerization, but it is easy to control the degree of polymerization of the graft monomer (graft ratio). It is preferable because almost the entire amount of the monomer impregnated in the base material can be graft-polymerized and the graft monomer is not consumed more than necessary. Any of the above graft polymerization methods can be selected depending on the purpose. In the present invention, for example, a long sheet-like material (fabric) such as a nonwoven fabric is used as a fiber having a core-sheath structure or an aggregate thereof. In this case, it is preferable to use impregnation gas phase graft polymerization.

  Further, in the graft polymer obtained by graft polymerization, one end of the graft side chain is firmly bonded to the base material covalently so that the graft is translated as “grafting”, while the other end is Since it does not participate in binding, the mobility of the side chain is large. For this reason, especially the graft side chain of the present invention having a highly hydrophilic functional group called an anion exchange group swells in an aqueous solution system such as water treatment, and can function more efficiently. In particular, since the microbial carrier of the present invention has one of the purposes of microbial adsorption and retention (immobilization) in an aqueous solution, the graft side chain having an anion exchange group that swells in an aqueous solution is used as a microbial immobilization product. It is extremely effective when used in water. This is because, together with the positive charge due to the anion exchange group, the graft side chain covers the surface of the carrier substrate, thereby providing a surface state with higher affinity suitable for microorganism adsorption.

  In the present invention, an anion exchange group can be introduced into a fiber having a core-sheath structure (described in detail later) by using a radiation graft polymerization method. In this case, an anion exchange group can be introduced not only into the surface of the fiber but also into the interior, and by appropriately selecting the radiation graft polymerization method and the material of the core and the sheath, mainly the sheath Graft polymerization can be performed. The dimensional change of the sheath part depends on the graft ratio. The graft ratio and graft polymerization method can be appropriately selected according to the microorganism to be supported, the type of substance to be removed by biological treatment, the type of anion exchange group to be introduced, the method of using the microorganism support, the required performance, and the like. For example, when the combination of the core and sheath of the composite fiber is (core) polyethylene terephthalate (PET) / (sheath) polyethylene (PE), (core) polypropylene (PP) / (sheath) PE When graft polymerization is carried out in an impregnation batch type following γ-ray irradiation, the sheath part is peeled off, and a large group of microorganisms such as activated sludge can be efficiently retained, and dropout can be minimized. In other words, when graft polymerization is performed on a composite fiber having a core-sheath structure, the size of the sheath part increases, peeling occurs between the core part and the sheath part, and folds are generated in the sheath. Increase. For this reason, microorganisms can be carried efficiently.

Microbial carrier base material In the present invention, the microbial carrier base material comprises a composite fiber. In the present invention, the composite fiber means a fiber made by combining two or more materials having different functions. As the composite fiber of the present invention, for example, a fiber having a core-sheath structure known as a heat-sealing fiber, or a fiber manufactured by a multicomponent spinning method (for example, a peeled split fiber) can be preferably used. A composite fiber having a sheath structure is particularly preferred. On the other hand, when chemical modification is performed on a fiber composed of a single component instead of a composite fiber, if the fiber is chemically modified to ensure the strength of the fiber, the tensile strength and elongation of the fiber will rapidly increase. It is known that it will decline. As described above, since radiation graft polymerization is chemically modified to the inside of the fiber that is the base material, in the present invention, it is necessary to use a composite fiber instead of a fiber made of a single material.

  Here, in the present invention, the composite fiber having the core-sheath structure is different from the material constituting the inner side (core part) of the fiber and the material constituting the outer side (sheath part) of the fiber, and has a double structure. It is a composite fiber. The conjugate fiber of the present invention is preferably a conjugate fiber having a core-sheath structure.

  Moreover, the composite fiber of this invention can take various structures. For example, in the case of a composite fiber having a core-sheath structure, the core part may be one or plural. As an example, FIG. 1 shows a cross-sectional view of a composite fiber having a core-sheath structure with one core (single core), and FIG. 2 shows a composite fiber having a core-sheath structure with multiple cores (multi-core). A cross-sectional view is shown. The core portion and the sheath portion may be concentric as shown in FIG. 1 or may be eccentric. Also, a split fiber type composite fiber as shown in FIG. 3 can be used.

  The composite fiber having a core-sheath structure can have a wide variety of properties by changing the ratio of thickness, difference in material, combinations of the same material but different physical properties, etc. for the core and sheath. Different functions can be assigned to the core and sheath, for example, maintaining the physical strength and elongation by the core, and functional aspects such as texture and wettability by the sheath to the composite fiber. Can be granted. In particular, when a composite fiber having a core-sheath structure is used in the present invention, the outer sheath part can be subjected to various surface modifications such as chemical modification, and the required strength can be secured at the inner core part, which is extremely preferable. In the present invention, it is preferable that the core material has a role of maintaining physical strength and elongation, and that an anion exchange group is introduced into the sheath portion. And both. Therefore, for example, it is preferable that the sheath part is a material capable of generating radicals by irradiation with radiation, and the core part is a material which hardly causes generation of radicals and / or polymer collapse by irradiation of radiation.

  Any known material can be used in the conjugate fiber of the present invention. Examples of materials that can be used for the composite fiber of the present invention include polyethylene (PE), polyethylene terephthalate (PET), polypropylene (PP), polybutene, polystyrene and other polyolefins, polyvinyl chloride and polytetrafluoroethylene (PTFE). ), Halogenated polyolefins, ethylene-tetrafluoroethylene copolymers, olefins and halogenated polyolefin copolymers, ethylene-vinyl alcohol copolymers (EVOH), ethylene-vinyl acetate (EVA) Examples thereof include copolymers of olefins and other monomers, nylon, aramid, vinylon, vinylidene, polyester, polyacrylic acid, polyurethane and the like. Preferably, polyolefin, more preferably polyethylene, polypropylene, and polyethylene terephthalate can be used.

  When using a composite fiber having a core-sheath structure in the present invention, the material of the core is preferably a material having a high melting point, heat resistance and excellent radiation resistance. For example, polyolefins, polyethylene Polyesters typified by terephthalate and polybutylene terephthalate, polypropylene, high-density polyethylene, or combinations thereof can be suitably used. On the other hand, the material of the sheath is preferably a material having a low melting point and good thermal adhesion, and a property of radical generation / preservation by radiation, such as polyolefin-based materials, more specifically, low-density polyethylene, Medium density polyethylene, polyvinyl alcohol and combinations thereof can be suitably used.

  The combination of the material of the core part and the material of the sheath part may be any, but the combination of PP (core part) and / or PET (core part) and PE (sheath part) is preferable. Moreover, it is preferable that the material of the core part has a higher melting point than the material of the sheath part. In this case, it is preferable that the fiber having the core-sheath structure is made into a non-woven fabric by a heat-sealing method. This is because each fiber is heat-sealed at the sheath portion, so that the strength as a fiber aggregate is secured, and the fiber This is because it is possible to reduce the omission of the material.

  The weight ratio between the sheath portion and the core portion of the fiber having a core-sheath structure is preferably in the range of 0.1-10. If it is less than 0.1, the graft ratio of the sheath must be very high in order to obtain a sufficient amount of functional groups, and the strength becomes weak. Moreover, when it exceeds 10, the ratio for which the sheath part in a composite fiber accounts will become high too much, and the effect made into the core-sheath structure will become small.

  In the present invention, the composite fiber base material is preferably a composite fiber aggregate from the viewpoint of water permeability and contact efficiency between the substance to be treated in the water to be treated and the immobilized microorganism. As the aggregate, a woven fabric or a nonwoven fabric comprising a composite fiber is more preferable. When the fiber assembly is used in the present invention, various characteristics of the fiber assembly as a base material (for example, a large void, a large specific surface area, a large amount of microorganisms to be loaded, a pressure loss during passage of water) Small, easy molding process, etc.) can be utilized. Here, as for the nonwoven fabric, it is sufficient if the fibers are sufficiently intertwined so that the fibers do not flow out or fall off. For example, in applications where strength is required, the fibers are partially bonded to each other by heat fusion treatment or the like. What is done is preferable.

  An example of a fiber assembly comprising a composite fiber having a core-sheath structure that can be preferably used in the present invention is a heat-sealed nonwoven fabric. In the heat-sealed nonwoven fabric, the sheath has not only the role (function) as described above but also the role (function) as an adhesive. For example, a composite fiber having a core-sheath structure in which PE is used for the sheath part is heat-treated at a temperature not lower than the melting point of the PE and not higher than the melting point of the material of the core part, so that only the PE in the sheath part is melted. In a fiber assembly including such fibers, adjacent fibers are bonded by the material of the sheath portion melted by heat, and the form of the fiber assembly is stabilized. That is, a fiber assembly such as a heat-sealed nonwoven fabric has extremely high strength and does not drop off fibers or change in voids, so that it can be suitably used even in severe use situations such as water treatment. The composite fiber having a core-sheath structure that constitutes such a fiber assembly includes, for example, a low melting point PE (melting point: 120 ° C. to 130 ° C.) as the material of the sheath part and PP (melting point: 170 ° C.) as the core part material. PET (melting point 270 ° C) is used. In addition, it cannot be overemphasized that the fiber assembly of this invention is not necessarily limited only to a heat-fusion nonwoven fabric.

In the present invention, the side chain introduced into the composite fiber substrate by graft polymerization has an anion exchange group. This is because many microorganisms are usually negatively charged, so that anion exchange groups are introduced into the fiber base and positively charged to increase the adsorption rate and adsorption amount of the microorganisms on the carrier, so that they do not fall off. This is to reduce it. By adopting such a configuration, when the microorganism carrier of the present invention is applied to water treatment or the like by adsorbing microorganisms, the carrying operation can be performed quickly. In addition, since the carrier is negatively charged when a cation exchange group is introduced, it is not suitable for the present invention. The microorganisms carried by the microorganism carrier of the present invention are not particularly limited, but negatively charged microorganisms are preferred. The carrier of the present invention can carry a single kind of microorganisms, but can also carry an aggregate of a plurality of kinds of microorganisms (for example, activated sludge).

  Suitable anion exchange groups in the present invention include one or more selected from a primary amino group, a secondary amino group, a tertiary amino group, and a quaternary ammonium group. If a negatively charged microorganism is simply adsorbed to a positively charged microorganism carrier, a larger and more positively charged quaternary ammonium group is most preferred as a functional group on the microorganism carrier. However, since the basicity becomes stronger at the same time, there is a possibility that an adverse effect on microorganisms may appear. In particular, in the case where the quaternary ammonium group has a long-chain alkyl group used for an antibacterial agent or the like, it is unsuitable for applications utilizing the activity of decomposition by microorganisms. Tertiary amino groups are sometimes preferred for carrying out specific functions such as supporting microorganisms and degrading contaminants without losing the activity of the microorganisms. In general, when a secondary or primary amino group (amino group) is used rather than a tertiary amino group, the adsorptive power becomes weak. The quantity and quantity of anion exchange groups to be introduced can be determined according to the application, required performance, and the like.

  As a method of introducing an anion exchange group into the graft side chain, (1) a method of introducing a monomer having an anion exchange group by graft polymerization, and (2) introduction of a monomer having no anion exchange group by graft polymerization, Methods for converting to exchange groups are known, and any method can be employed in the present invention. Examples of the monomer having an anion exchange group include vinylbenzyltrimethylammonium chloride (VBTAC), dimethylaminoethyl methacrylate (DMAEMA), diethylaminoethyl methacrylate (DEAEMA), dimethylaminopropylacrylamide (DMAPAA) and the like. Examples of monomers that can be converted into ion exchange groups include styrene (St), glycidyl methacrylate (GMA), glycidyl acrylate, chloromethylstyrene (CMS), and vinylpyridine (VP).

  In the present invention, the graft side chain preferably has an anion exchange group having an ion exchange capacity of 0.5 meq / g or more. This is because when the anion exchange capacity is 0.5 meq / g or more, a sufficient amount of microorganisms can be supported, and the substance to be treated with microorganisms can be adsorbed. If it is less than this exchange capacity, sufficient charge cannot be obtained, and the hydrophilicity of the substrate is insufficient, so that the amount of microorganisms supported and the amount of contaminants adsorbed may be reduced. In this specification, the ion exchange capacity means the total number of exchange groups per unit weight of the ion exchanger.

  In order to obtain a value of at least 0.5 meq / g or more, although it depends on the molecular weight of the monomer to be grafted, it is usually preferred that the graft ratio (weight increase rate) is 30% or more. Depending on the material of the base material and the polymerization method, the core part and the sheath part may be peeled off, resulting in unevenness on the fiber surface. This unevenness increases the surface area, which is advantageous for supporting the microorganism group. Large microorganisms such as activated sludge can be efficiently retained and omission can be minimized. FIG. 4 shows an electron micrograph of an untreated substrate, and FIG. 5 shows an electron micrograph of a carrier supporting microorganisms.

Use Mode of Microbial Carrier of the Present Invention The microbial carrier of the present invention can be used for any technique using microorganisms (for example, separation, purification, removal, decomposition, production, etc. of specific substances using microorganisms), and preferably Can be used for water treatment using microorganisms, for example, for general water treatment and for decomposing and removing specific components. Since the present invention is a microbial carrier for biologically treating wastewater or the like, various embodiments are possible depending on the type (state) of wastewater and the purpose of treatment (or treatment target). However, unlike the conventional carrier that non-selectively attaches microorganisms over the course of operation as in the prior art, the microorganism carrier of the present invention is characterized by its excellent initial ability to adsorb microorganisms. However, it is desirable to perform selective treatment by selectively adsorbing microorganisms that treat the same.

  For example, bisphenol A is widely used as a raw material for epoxy resins, polycarbonate resins, polyvinyl chloride resins, and the like, and acts as an endocrine disrupting substance (so-called environmental hormone) that has an adverse effect on ecosystems in water environments such as rivers and lakes. It is pointed out that removal treatment to extremely low concentrations is desired. In such a case, the microorganism carrier of the present invention is selectively adsorbed with microorganisms capable of effectively decomposing bisphenol A in advance, and the resulting microorganism carrier is placed in a reaction vessel to remove bisphenol A. Do. Such a trace component may be used for the treatment target, and any kind such as a chromaticity component, an odor component, a hardly decomposable component, etc. may be used, but a non-selective microbial layer is formed on the microbial carrier, thereby inhibiting selective treatment. It is desirable to target water that has been first-treated so as not to occur. On the other hand, if the purpose is to reduce the BOD component, an activated sludge layer is formed on the surface of the microorganism carrier, and the activated sludge layer is removed more than necessary by regular backwashing so as not to impede liquid permeability. It is desirable.

As another aspect, it can be used as a microorganism removal filter for removing negatively charged microorganisms for gas, highly treated water, and the like.
The usage form of the microbial carrier of the present invention is not particularly limited, and various methods can be adopted. For example, it can be used in a column method or a suspension method. The column method uses a column-shaped reaction tank filled with a microbial carrier (or a microbial carrier carrying microorganisms) in a container (for example, a cylindrical container), and feeds water to be treated from one of the cylindrical containers. In this method, treated water is obtained from the other side. In the column method, the microorganism carrier is packed to such an extent that it cannot easily move in the reaction vessel. Therefore, it is preferable that the carrier piece (aggregate) constituting the microbial carrier forms a laminated structure of sheet-like materials or an entangled body in which fibers are large as a fiber aggregate. For example, it can be fixed as a filter to a frame, or laminated in a packed tower, and a liquid to be treated can be passed there to remove both particles and non-particle contaminants. In the suspension method, the microorganism carrier is suspended in the liquid phase of the water to be treated. In this case, the microbial carrier is dispersed in the liquid phase and has fluidity, and the microbial carrier can be easily moved in the reaction vessel. Therefore, it is preferable that the carrier piece (aggregate) constituting the microbial carrier is small enough to maintain fluidity or dispersibility, and the inside of the reaction vessel may be agitated in order to stabilize the processing performance. For example, the microbial carrier of the present invention cut to a certain size can be used by stirring in a tank.

Microbial carrier manufacturing method From one aspect, the present invention is a microbial carrier manufacturing method. For example, in one embodiment, the present invention includes a step of irradiating a composite fiber base material including a composite fiber having a core-sheath structure; a step of impregnating the base material with a polymerizable monomer; And a step of graft polymerization.

  In the graft polymerization process, any of liquid phase graft polymerization, gas phase graft polymerization, and impregnated gas phase graft polymerization can be used, but the degree of polymerization of the graft monomer (graft rate) can be controlled, and the graft monomer is more than necessary. Impregnated gas phase graft polymerization is preferred.

[Example 1]
Production of microbial carrier PET is the core and PE is the sheath. PE fiber is a composite fiber (average fiber diameter: 12 μm), and the basis weight is 55 g / m ² , 0.3 mm thick nonwoven fabric. Irradiated with 160 kGy. Next, this nonwoven fabric was impregnated with a solution of glycidyl methacrylate (GMA) in methanol (GMA concentration: 50% by weight) and reacted in the gas phase at 50 ° C. for 1 hour. The non-woven fabric after reaction was immersed in dimethylformamide (DMF) at 60 ° C. for 3 hours and washed. The obtained non-woven fabric was further washed with methanol and the weight after drying was measured. The graft ratio (weight increase rate) was 63%. This nonwoven fabric was immersed in a 30% by weight diethanolamine aqueous solution and reacted at 70 ° C. for 5 hours. The amount of tertiary amino groups introduced was calculated from the amount of acid adsorbed on the nonwoven fabric after the reaction and found to be 1.66 meq / g.

Microorganism support test Sphingomonas yanoikuyae BP-7 (FERM P-17919), BP-16 (FERM P-17920) were used as bisphenol A-degrading microorganisms. These degrading microorganisms were cultured in 200 ml of NB medium (manufactured by Difco) until the late logarithmic growth and used for immobilization on a carrier.

The non-woven fabric (15 cm square) produced by the above method was further cut into 7 mm square and put into a culture solution of degrading microorganisms. OD660nm was measured using an absorptiometer, and the amount of microorganisms attached after 1 hour from the nonwoven fabric was calculated from the decrease in OD660nm. The amount of BP-7 and BP-16 attached to the carrier was 1.9 × 10 ⁹ respectively. cells / cm ² and 5.3 × 10 ⁸ cells / cm ² . The unit indicating the amount of attached microorganisms is the number of cells per apparent area when the microorganism carrier nonwoven fabric is regarded as a sheet.

[Example 2]
In Example 1, a non-woven fabric having a graft ratio of 173% was obtained by setting the concentration of the methanol solution of GMA to 80% by weight and the graft polymerization conditions to 50 ° C. for 5 hours. Furthermore, after carrying out the same amination reaction as in Example 1, the amount of tertiary amino groups introduced was measured from the acid adsorption amount of the nonwoven fabric and found to be 2.91 meq / g.

This nonwoven fabric was subjected to the same microorganism loading test as in Example 1. The amount of microbial adherence after 1 hour was calculated from the decrease in the measured OD660nm, and the amount of BP-7 and BP-16 adhering to the carrier was 3.2 × 10 ⁹ cells / cm ² and 1.8 × 10 ⁹ cells, respectively. / cm ² .

[Comparative Example 1]
In Example 1, the concentration of the methanol solution of GMA was 10% by weight and the graft polymerization time was 2 hours to obtain a nonwoven fabric having a graft rate of 23%. Furthermore, after carrying out the same amination reaction as in Example 1, the amount of tertiary amino groups introduced was calculated from the amount of acid adsorbed on the nonwoven fabric and found to be 0.18 meq / g.

This nonwoven fabric was subjected to the same microorganism loading test as in Example 1. The amount of microbial adherence after 1 hour was calculated from the decrease in the measured OD660nm. The amounts of BP-7 and BP-16 adhering to the carrier were 2.1 × 10 ⁸ cells / cm ² and 0.2 × 10 ⁷ cells, respectively. / cm ² .

  In Comparative Example 1, compared with Examples 1 and 2, the graft ratio and ion exchange capacity were small. In addition, when the microbial adhesion amount after 1 hour was compared for the microorganism-immobilized products prepared in Example 1, Example 2 and Comparative Example 1, the microbial adhesion amount to the microbial carrier of Example 2 having the highest graft ratio was the largest. As the graft rate decreased, the amount of attached microorganisms also decreased. This is thought to be because more microorganisms could be adsorbed because the amount of anion exchange groups on the surface of the microorganism carrier could be increased by increasing the graft ratio. According to such a microorganism carrier having a high ability to support microorganisms, the target component in the water to be treated can be treated effectively.

[Example 3]
Microbial carrier production The core part is PP and the sheath part is PE, and the fabric weight (average fiber diameter 16μm) is 50g / m ² , and the nonwoven fabric is 20cm square with a thickness of 0.3mm. Irradiated. Next, this non-woven fabric was immersed in a solution of VBTAC / vinyl pyrrolidone / water = 4/4/1 (weight ratio), immersed in a solution of glycidyl methacrylate (GMA) / methanol = 1/1 (weight ratio), The reaction was carried out at 50 ° C. for 1 hour. The non-woven fabric after the reaction was immersed in pure water and washed at 70 ° C. for 3 hours. When the weight after drying was measured, the graft ratio (weight increase ratio) was 115%. This nonwoven fabric was dipped in a 5% by weight aqueous sodium hydroxide solution and regenerated. This nonwoven fabric had an ion exchange capacity of 1.32 meq / g.

Microorganism support test The same microorganism support test as in Example 1 was performed on Escherichia coli. A non-woven fabric (15 cm square) was cut into a 7 mm square and placed in a culture solution of E. coli. When the amount of microbial adherence after 1 hour was calculated from the decrease in the measured OD660nm value, the E. coli concentration was initially 5.1 × 10 ⁸ cells / ml, but after 2 hours it decreased to 600 cells / ml or less. It was confirmed that the grafted nonwoven fabric had an extremely high E. coli adsorption effect.

[Experimental Example 1] Bisphenol A treatment test Bisphenol A was treated with a decomposing microorganism-immobilized carrier for inflow water from a sewage treatment plant. In the experiment, 2 L of sewage inflow water was placed in a 5 L reactor equipped with a stirrer, and the immobilized product (225 cm ² ) prepared by the method of Example 2 was added thereto, and reacted at room temperature (25 ° C.) with aeration stirring. It was. Water was collected after the reaction for 2 hours, and the bisphenol A concentration was measured. In addition, the measurement of bisphenol A in wastewater was performed according to the sewage test method (Supplemental Provisional Version, Sewerage Association, 2002).

  The bisphenol A concentration of wastewater treated with the immobilized microorganism for 2 hours is shown in Table 1, but the bisphenol A concentration after the reaction for 2 hours was significantly reduced. Further, in the system in which the reaction was similarly performed for 2 hours without adding degrading bacteria, reduction of bisphenol A was not observed.

［実験例２］フェノール処理試験
フェノール分解菌Pseudomonas putida ATCC17514をフェノールを含む培地で２５℃、４日間培養し、この培養液に実施例２の方法で作成した不織布（２２５cm²）を投入した。反応槽内にフェノールを主とする廃水と洗浄した固定化物を投入し、DO 2mg/L、水温２５℃に維持して撹拌した。その結果、初期濃度４００mg/Lだったフェノールは、１時間の反応で９０％以上除去された。

[Experimental Example 2] Phenol Treatment Test The phenol-degrading bacterium Pseudomonas putida ATCC17514 was cultured in a medium containing phenol at 25 ° C. for 4 days, and the nonwoven fabric (225 cm ² ) prepared by the method of Example 2 was added to this culture solution. Wastewater mainly composed of phenol and the washed immobilized product were put into the reaction vessel, and the mixture was stirred while maintaining DO 2 mg / L and a water temperature of 25 ° C. As a result, 90% or more of phenol having an initial concentration of 400 mg / L was removed by reaction for 1 hour.

FIG. 1 is a cross-sectional view of a composite fiber (single core) of the present invention. FIG. 2 is a cross-sectional view of the conjugate fiber (multicore) of the present invention. FIG. 3 is a cross-sectional view of the conjugate fiber (split fiber type) of the present invention. FIG. 4 is an electron micrograph of an untreated substrate. FIG. 5 is an electron micrograph of a substrate carrying microorganisms (Sphingomonas yanoikuyae BP-7).

Claims (7)

  A microbial carrier comprising a composite fiber having a side chain introduced into a composite fiber base material by radiation graft polymerization, wherein the side chain has an anion exchange group.   The microbial carrier according to claim 1, wherein the composite fiber substrate comprises fibers having a core-sheath structure.   The microbial carrier according to claim 1 or 2, wherein the side chain anion exchange group has an ion exchange capacity of 0.5 meq / g or more.   4. The method according to claim 1, wherein the anion exchange group is at least one selected from a primary amino group, a secondary amino group, a tertiary amino group, and a quaternary ammonium group. The microbial carrier as described.   The microbial carrier according to any one of claims 1 to 4, wherein the composite fiber substrate is a fiber assembly.   The microbial carrier according to claim 5, wherein the fiber assembly is a woven fabric or a non-woven fabric. Irradiating a composite fiber substrate including a composite fiber having a core-sheath structure with radiation;
Impregnating the substrate with a polymerizable monomer;
Graft polymerizing the monomer to the substrate;
A method for producing a microbial carrier, comprising:

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