WO2017073346A1 - Bubble liquid concentration device, and device for generating highly dense fine bubble liquid - Google Patents

Bubble liquid concentration device, and device for generating highly dense fine bubble liquid Download PDF

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Publication number
WO2017073346A1
WO2017073346A1 PCT/JP2016/080426 JP2016080426W WO2017073346A1 WO 2017073346 A1 WO2017073346 A1 WO 2017073346A1 JP 2016080426 W JP2016080426 W JP 2016080426W WO 2017073346 A1 WO2017073346 A1 WO 2017073346A1
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Prior art keywords
liquid
bubble
membrane
separation membrane
bubbles
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PCT/JP2016/080426
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French (fr)
Japanese (ja)
Inventor
直樹 永岡
孝夫 土井
小原　知海
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日東電工株式会社
Idec株式会社
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Publication of WO2017073346A1 publication Critical patent/WO2017073346A1/en

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
    • B01D61/14—Ultrafiltration; Microfiltration
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D69/00—Semi-permeable membranes for separation processes or apparatus characterised by their form, structure or properties; Manufacturing processes specially adapted therefor
    • B01D69/02—Semi-permeable membranes for separation processes or apparatus characterised by their form, structure or properties; Manufacturing processes specially adapted therefor characterised by their properties
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
    • B01F23/00—Mixing according to the phases to be mixed, e.g. dispersing or emulsifying
    • B01F23/20—Mixing gases with liquids
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
    • B01F25/00—Flow mixers; Mixers for falling materials, e.g. solid particles
    • B01F25/20—Jet mixers, i.e. mixers using high-speed fluid streams
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
    • B01F25/00—Flow mixers; Mixers for falling materials, e.g. solid particles
    • B01F25/30—Injector mixers

Definitions

  • the present invention relates to a bubble liquid concentrating device for increasing the concentration of bubbles in a supply liquid containing bubbles by a separation membrane, and a high-density fine bubble liquid generating device using the same, and in particular, a diameter of less than 1 ⁇ m existing in a liquid. This is useful as a technique for increasing the concentration of bubbles (ultra fine bubbles, UFB).
  • Non-Patent Document 1 discloses an apparatus that generates a large amount of ultrafine bubbles.
  • nonpatent literature 2 it is reported about the ultra fine bubble stably existing in water.
  • Patent Document 2 discloses that a part of the liquid containing fine bubbles is transmitted through a filtration filter that does not pass fine bubbles having a diameter larger than 200 nm for the purpose of easily generating a liquid having a high density of fine bubbles. And a method for producing a high-density microbubble liquid that obtains a high-density microbubble liquid that is the remainder of the liquid is disclosed.
  • Patent Document 2 mentions the pore diameter of the filter, but does not disclose the material or the like.
  • an object of the present invention is to provide a bubble liquid concentrating device capable of obtaining a high-concentration bubble-containing liquid and a high-density fine bubble liquid generating apparatus using the same.
  • the present inventors have found that the contact angle between the tangential direction of the bubble and the surface of the separation membrane in water (hereinafter referred to as the bubble contact angle). It was found that the above-mentioned object can be achieved by using a separation membrane having an angle of 140 ° or more, and the present invention has been completed.
  • the bubble liquid concentrating device of the present invention is a bubble liquid concentrating device for increasing the concentration of bubbles in a supply liquid containing bubbles by a separation membrane, wherein the separation membrane has a bubble contact angle in water with respect to at least one surface. Is 140 ° or more.
  • the bubble liquid concentrating device of the present invention since the bubble contact angle on the surface of the separation membrane used for concentration is 140 ° or more, it is difficult for bubbles to adhere to the membrane surface. That is, as shown in FIG. 1, the bubble adhesion state is greatly different between the case where the bubble contact angle in water is 104 ° (FIG. 1a) and the case where the bubble contact angle is 167 ° (FIG. 1c). It is considered that the liquid can permeate while suppressing the disappearance of the bubbles by making the bubbles less likely to adhere to the surface. As a result, it is possible to suppress the disappearance of bubbles due to contact with the membrane during the bubble liquid concentration, and a high-concentration bubble-containing liquid can be obtained.
  • the supply liquid contains bubbles having a diameter of less than 1 ⁇ m.
  • the bubble contact angle on the surface of the separation membrane is 140 ° or more, it is possible to make it difficult to attach bubbles to the membrane surface even for fine bubbles having a diameter of less than 1 ⁇ m, and to efficiently separate and concentrate the bubbles. it can.
  • the one surface of the separation membrane preferably has a porous structure having an average pore diameter of 1,000 nm or less or a non-porous structure. With such an average pore diameter, bubbles having a diameter of less than 1 ⁇ m can be efficiently separated and concentrated.
  • a hydrophilic polymer porous layer or a non-porous layer is provided on the one surface.
  • a separation membrane having a bubble contact angle in water of 140 ° or more is easily obtained.
  • the bubble liquid concentrating device of the present invention preferably includes a membrane module including a membrane element having the separation membrane and a container that accommodates the membrane element and forms a concentration side channel and a permeation side channel.
  • a membrane module including a membrane element having the separation membrane and a container that accommodates the membrane element and forms a concentration side channel and a permeation side channel.
  • the membrane element preferably has a structure that allows the permeate to permeate the other membrane surface of the separation membrane while the supply fluid flows along one membrane surface of the separation membrane.
  • a circulation channel for returning the concentrated liquid discharged from the membrane module to the supply liquid.
  • a high-density fine bubble liquid generator of the present invention includes any of the bubble liquid concentrators and a bubble generator that supplies a supply liquid containing bubbles having a diameter of less than 1 ⁇ m to the bubble liquid concentrator. It is characterized by that.
  • the bubble liquid concentrator includes a separation membrane having a bubble contact angle in water of 140 ° or more on at least one surface. It is possible to suppress the disappearance of bubbles due to the contact, and a high-concentration bubble-containing liquid can be obtained.
  • the supply liquid generated by the bubble generator includes not only bubbles having a diameter of less than 1 ⁇ m, but also bubbles having a diameter of 1 ⁇ m or more to 500 nm or less. Therefore, the bubble-containing liquid obtained by the bubble liquid concentrating device of the present invention may contain bubbles having a diameter of 1 ⁇ m or more.
  • FIG. 1 It is a schematic block diagram which shows an example of the high-density fine bubble liquid production
  • the bubble liquid concentrating device of the present invention is a bubble liquid concentrating device for increasing the concentration of bubbles in a supply liquid containing bubbles by a separation membrane, wherein the separation membrane has a bubble contact angle in water of at least one surface of 140. It is characterized by being at least °. That is, the bubble liquid concentrating device of the present invention includes a separation membrane 2 for condensing bubble liquid, for example, as shown in FIG. In addition, the bubble liquid concentrating device of the present invention, as shown in FIG. 3, for example, forms a membrane element 1 having a separation membrane 2 and the membrane element 1 to form a concentration side channel and a permeation side channel. A membrane module 30 including the container 31 is preferably provided. First, the separation membrane for concentrating bubble liquid will be described in detail.
  • the separation membrane for concentrating bubble liquid in the present invention is used, for example, when concentrating a liquid (bubble liquid) containing bubbles having a diameter of 100 ⁇ m or less to increase the concentration of contained bubbles. It is preferably used when concentrating a liquid containing bubbles of less than 1 ⁇ m.
  • Bubbles with a diameter of less than 1 ⁇ m present in the liquid are called ultra fine bubbles (UFB), and have a property that the liquid is stable for a long period of time and is transparent in comparison with a microvalve having a larger diameter.
  • UFB ultra fine bubbles
  • UFB has characteristics such as gas enrichment, surface activity, crushing, charging, specific surface area increase, etc., and can perform sheet-fed peeling, emulsification, aroma encapsulation, freshness maintenance, and the like.
  • UFB is used for semiconductor devices, flat panel displays, electronic devices, solar cells, secondary batteries, food, beverages, cosmetics, medicines, medicine, plant cultivation, new functional materials, removal of radioactive substances, etc. It can be used for various purposes.
  • UFB can be generated by various methods. For example, a mixed fluid in which a gas and a liquid are mixed in a fluid swirl chamber is swirled at high speed, and bubbles are refined by shearing force generated in the swirl flow. A method is mentioned.
  • liquid having bubbles examples include water, an aqueous alcohol solution, ozone water, an acidic aqueous solution, an alkaline aqueous solution, and a surfactant aqueous solution.
  • the average diameter of UFB is usually less than 1 ⁇ m and preferably 0.01 to 0.5 ⁇ m from the viewpoint of developing the above functions. Further, the number density in the liquid before concentration is preferably at least 30 million / mL or more from the viewpoint of increasing the number density after concentration, more preferably 100 million / mL to 1 billion / mL. preferable.
  • the separation membrane for concentrating bubble liquid in the present invention is characterized in that at least one surface has a bubble contact angle in water of 140 ° or more, but both surfaces may have a bubble contact angle of 140 ° or more. .
  • the surface is disposed on the supply liquid side (the undiluted stock solution) and disposed on the permeate side from the other surface.
  • the bubble contact angle in water is 140 ° or more and less than 180 °, but it is preferably 145 ° or more and 150 ° from the viewpoint of more reliably suppressing the disappearance of bubbles due to contact with the membrane during bubble liquid concentration.
  • the above is more preferable, and 160 or more is most preferable.
  • the bubble contact angle in water is preferably 178 ° or less, more preferably 175 ° or less, and most preferably 170 ° or less from the viewpoint of ease of production of the separation membrane.
  • the separation membrane having such a bubble contact angle can be obtained by a method of hydrophilizing at least the surface of the hydrophobic polymer porous layer, or by producing a separation membrane with a hydrophilic polymer.
  • the separation membrane is produced with a hydrophilic polymer like the latter, for example, by using a cellulose resin, a polyamide resin, a polyvinyl alcohol resin, an epoxy resin, or by introducing a crosslinked structure, A separation membrane having a bubble contact angle of can be obtained.
  • a separation membrane is preferably one in which a hydrophilic polymer porous layer is formed on one side of a nonwoven fabric layer from the viewpoint of durability, pressure resistance, permeation flow rate, etc. of the separation membrane.
  • a flat membrane but also a hollow fiber membrane and a tubular membrane can be used.
  • a method of hydrophilizing the surface of the hydrophobic polymer porous layer is preferable.
  • the hydrophilic treatment is performed by coating with a hydrophilic substance or grafting with a hydrophilic polymer.
  • Examples of the separation membrane used for the hydrophilization treatment include those having a hydrophobic polymer porous layer. From the viewpoint of the durability of the separation membrane, pressure resistance, permeation flow rate, etc., the polymer porous layer is one side of the nonwoven fabric layer. What is formed in is preferable. In the present invention, not only a flat membrane but also a hollow fiber membrane and a tubular membrane can be used.
  • hydrophobic polymer examples include various polymers such as polysulfone and polyarylethersulfone exemplified by polyethersulfone, polyimide, polyvinylidene fluoride, epoxy resin, polyethylene, polypropylene, and fluororesin.
  • polysulfone and polyarylethersulfone are preferable because they are chemically, mechanically and thermally stable.
  • the separation membrane used for the hydrophilization treatment may be an asymmetric membrane having a different average pore size on both sides of the membrane or a symmetric membrane, but is preferably an asymmetric membrane from the viewpoint of treatment efficiency during concentration. .
  • the average pore size of the separation membrane (the average pore size of the surface having the smaller pore size) is preferably 0.001 to 2 ⁇ m, preferably 0.05 to 2 ⁇ m, from the viewpoints of the pore size after the hydrophilic treatment and the ease of the hydrophilic treatment. 1 ⁇ m is more preferable, and 0.01 to 0.4 ⁇ m is even more preferable.
  • the thickness of the separation membrane or polymer porous layer is preferably 10 to 300 ⁇ m, more preferably 50 to 200 ⁇ m.
  • the thickness of the nonwoven fabric layer is preferably 30 to 200 ⁇ m, more preferably 50 to 150 ⁇ m.
  • the nonwoven fabric layer is not particularly limited as long as it provides an appropriate mechanical strength while maintaining the separation performance and permeation performance of the separation membrane, and a commercially available nonwoven fabric can be used.
  • a material made of polyolefin, polyester, cellulose or the like is used, and a material in which a plurality of materials are mixed can also be used.
  • polyester in terms of moldability.
  • a long fiber nonwoven fabric or a short fiber nonwoven fabric can be used as appropriate, but a long fiber nonwoven fabric can be preferably used from the viewpoint of fine fuzz that causes pinhole defects and uniformity of the film surface.
  • the air permeability of the nonwoven fabric layer at this time is not limited to this, but it can be about 0.5 to 10 cm 3 / cm 2 ⁇ s, and 1 to 5 cm 3 / s. Those having a size of about cm 2 ⁇ s are preferably used.
  • hydrophilic polymer separation membranes can be used as they are.
  • hydrophobic polymer separation membrane can be used for hydrophilization treatment. It is also possible to manufacture the separation membrane by a known method.
  • the polymer separation membrane can be produced by a method generally called a wet method or a dry wet method.
  • a solution preparation step in which polysulfone, a solvent and various additives are dissolved
  • a coating step in which the nonwoven fabric is coated with the solution
  • a drying step in which the solvent in the solution is evaporated to cause microphase separation, a water bath, etc.
  • the polymer porous layer on the nonwoven fabric can be formed through an immobilization step of immobilization by dipping in a coagulation bath.
  • the thickness of the polymer porous layer can be set by adjusting the solution concentration and the coating amount after calculating the ratio of impregnation into the nonwoven fabric layer.
  • the hydrophilization treatment is preferably performed by hydrophilic substance coating or hydrophilic polymer grafting.
  • surface treatment by introduction of hydrophilic groups plasma treatment, excimer laser irradiation, surface treatment by corona discharge treatment, The hydrophilization treatment is possible also by the above.
  • hydrophilic substance There are two methods for coating a hydrophilic substance: a method using a low molecule as a hydrophilic substance and a method using a polymer, but it is also possible to polymerize by performing a polymerization reaction using a low molecule.
  • a polymer such as polyvinyl alcohol, polyethylene glycol, polyvinyl pyrrolidone, polyacrylic acid, hydroxypropyl cellulose, etc. is dissolved in a solvent, and the solution is applied or impregnated on a separation membrane.
  • the method of making it dry is mentioned. In that case, it is also possible to carry out a crosslinking reaction between the polymers or the separation membrane using a crosslinking agent or the like.
  • polyhydric alcohols such as sucrose fatty acid ester, sorbitol and glycerin, surfactants such as sodium dodecylbenzenesulfonate, sodium dodecylsulfate and sodium laurylsulfate, sodium lactate
  • surfactants such as sodium dodecylbenzenesulfonate, sodium dodecylsulfate and sodium laurylsulfate, sodium lactate
  • a method of dissolving in a solvent using glycerin or the like applying or impregnating the solution to a separation membrane, and then drying.
  • hydrophilic substance having a functional group having reactivity with the separation membrane to cause a reaction between the separation membranes.
  • a vinyl type hydrophilic monomer When grafting a hydrophilic polymer, for example, a vinyl type hydrophilic monomer is used.
  • a vinyl type hydrophilic monomer acrylic acid, methacrylic acid, hydroxymethyl methacrylic acid, sulfoethyl methacrylic acid, styrene sulfonic acid or alkali metal salts thereof can be used.
  • grafting When grafting is performed, it is preferable to perform electron graft irradiation on the separation membrane, chemical graft polymerization using an initiator, photoinitiated graft polymerization, or the like. In addition, after the polymerization is completed, excess monomer is removed.
  • a method of coating by carrying out a polymerization reaction using a low molecule a method of carrying out a polymerization reaction using a vinyl type hydrophilic monomer used for grafting, a polymerization initiator, and a crosslinking agent if necessary, Alternatively, a method using interfacial polymerization as described below can be used.
  • a polyamide-based coat layer is formed, and generally a homogeneous film having no visible pores can be obtained.
  • a polyamide-based coating layer for example, a polyamide-based separation functional layer obtained by interfacial polymerization of a polyfunctional amine component and a polyfunctional acid halide component on a porous support membrane is well known.
  • Such a polyamide-based separation functional layer is known to have a pleated microstructure, and the thickness of this layer is not particularly limited, but is about 0.05 to 2 ⁇ m, preferably 0.1 to 1 ⁇ m. It is known that if this layer is too thin, film surface defects are likely to occur, and if it is too thick, the transmission performance deteriorates.
  • the method for forming the polyamide-based separation functional layer on the surface of the polymer porous layer is not particularly limited, and any known method can be used. Examples of the method include an interfacial polymerization method, a phase separation method, and a thin film coating method. In the present invention, the interfacial polymerization method is particularly preferably used. In the interfacial polymerization method, for example, the polymer porous layer is coated with a polyfunctional amine component-containing amine aqueous solution, and then an organic solution containing a polyfunctional acid halide component is brought into contact with the amine aqueous solution-coated surface to cause interfacial polymerization. This is a method for forming a skin layer.
  • a removal method a method of inclining a target film, a method of blowing off a gas, a rubber, For example, a method of scraping off a blade by contacting the blade is preferably used.
  • the time required for the aqueous amine solution and the organic solution to contact is approximately 1 to 120 seconds, although it depends on the composition of the aqueous amine solution, the viscosity, and the pore diameter of the surface of the porous support membrane. Is about 2 to 40 seconds. If the interval is too long, the aqueous amine solution may permeate and diffuse deep inside the porous support membrane, and a large amount of unreacted polyfunctional amine component may remain in the porous support membrane, resulting in problems. . When the application interval of the solution is too short, an excessive amine aqueous solution remains, so that the film performance tends to be lowered.
  • the heating temperature is more preferably 70 to 200 ° C., particularly preferably 80 to 130 ° C.
  • the heating time is preferably about 30 seconds to 10 minutes, more preferably about 40 seconds to 7 minutes.
  • the polyfunctional amine component contained in the amine aqueous solution is a polyfunctional amine having two or more reactive amino groups, and examples thereof include aromatic, aliphatic, and alicyclic polyfunctional amines.
  • the aromatic polyfunctional amine include m-phenylenediamine, p-phenylenediamine, o-phenylenediamine, 1,3,5-triaminobenzene, 1,2,4-triaminobenzene, 3,5- Examples thereof include diaminobenzoic acid, 2,4-diaminotoluene, 2,6-diaminotoluene, N, N′-dimethyl-m-phenylenediamine, 2,4-diaminoanisole, amidol, xylylenediamine and the like.
  • Examples of the aliphatic polyfunctional amine include ethylenediamine, propylenediamine, tris (2-aminoethyl) amine, and n-phenyl-ethylenediamine.
  • Examples of the alicyclic polyfunctional amine include 1,3-diaminocyclohexane, 1,2-diaminocyclohexane, 1,4-diaminocyclohexane, piperazine, 2,5-dimethylpiperazine, 4-aminomethylpiperazine and the like. It is done. These polyfunctional amines may be used alone or in combination of two or more.
  • the polyfunctional acid halide component contained in the organic solution is a polyfunctional acid halide having two or more reactive carbonyl groups, and examples thereof include aromatic, aliphatic, and alicyclic polyfunctional acid halides.
  • aromatic polyfunctional acid halide examples include trimesic acid trichloride, terephthalic acid dichloride, isophthalic acid dichloride, biphenyldicarboxylic acid dichloride, naphthalenedicarboxylic acid dichloride, benzenetrisulfonic acid trichloride, benzenedisulfonic acid dichloride, and chlorosulfonylbenzene. And dicarboxylic acid dichloride.
  • Examples of the aliphatic polyfunctional acid halide include propanedicarboxylic acid dichloride, butanedicarboxylic acid dichloride, pentanedicarboxylic acid dichloride, propanetricarboxylic acid trichloride, butanetricarboxylic acid trichloride, pentanetricarboxylic acid trichloride, glutaryl halide, azide. Poil halide etc. are mentioned.
  • Examples of the alicyclic polyfunctional acid halide include cyclopropane tricarboxylic acid trichloride, cyclobutane tetracarboxylic acid tetrachloride, cyclopentane tricarboxylic acid trichloride, cyclopentane tetracarboxylic acid tetrachloride, cyclohexane tricarboxylic acid trichloride, and tetrahydro Examples include furantetracarboxylic acid tetrachloride, cyclopentanedicarboxylic acid dichloride, cyclobutanedicarboxylic acid dichloride, cyclohexanedicarboxylic acid dichloride, and tetrahydrofurandicarboxylic acid dichloride.
  • polyfunctional acid halides may be used alone or in combination of two or more. Among them, it is preferable to use an aromatic polyfunctional acid halide that provides a dense separation functional layer. Moreover, it is preferable to form a crosslinked structure using a trifunctional or higher polyfunctional acid halide as at least a part of the polyfunctional acid halide component.
  • the concentration of the polyfunctional amine component in the aqueous amine solution is not particularly limited, but is preferably 0.1 to 7% by weight, more preferably 1 to 5% by weight. If the concentration of the polyfunctional amine component is too low, defects are likely to occur in the skin layer, and the salt blocking performance tends to be reduced. On the other hand, when the concentration of the polyfunctional amine component is too high, it becomes too thick and the permeation flux tends to decrease.
  • the concentration of the polyfunctional acid halide component in the organic solution is not particularly limited, but is preferably 0.01 to 5% by weight, more preferably 0.05 to 3% by weight. If the concentration of the polyfunctional acid halide component is too low, the unreacted polyfunctional amine component is increased, and defects are likely to occur in the skin layer. On the other hand, if the concentration of the polyfunctional acid halide component is too high, the amount of unreacted polyfunctional acid halide component increases, so that the skin layer becomes too thick and the permeation flux tends to decrease.
  • the organic solvent containing the polyfunctional acid halide is not particularly limited as long as it has low solubility in water and does not deteriorate the porous support membrane, and can dissolve the polyfunctional acid halide component.
  • cyclohexane examples thereof include saturated hydrocarbons such as heptane, octane and nonane, and halogen-substituted hydrocarbons such as 1,1,2-trichlorotrifluoroethane.
  • Preferred is a saturated hydrocarbon having a boiling point of 300 ° C. or lower, more preferably a boiling point of 200 ° C. or lower.
  • the additive may add the additive for the purpose of the improvement of various performance and a handleability to the said amine aqueous solution and organic solution.
  • the additive include polymers such as polyvinyl alcohol, polyvinyl pyrrolidone and polyacrylic acid, polyhydric alcohols such as sorbitol and glycerin, and surfactants such as sodium dodecylbenzenesulfonate, sodium dodecylsulfate, and sodium laurylsulfate.
  • Basic compounds such as sodium hydroxide, trisodium phosphate and triethylamine for removing hydrogen halide produced by polymerization, acylation catalysts, and solubility parameters described in JP-A-8-224452 are 8 to 14 (cal / Cm 3 ) 1/2 compound and the like.
  • a coating layer composed of various polymer components may be further provided on the exposed surface of the polyamide-based separation functional layer.
  • the polymer component is not particularly limited as long as it does not dissolve the separation functional layer and the porous support membrane and does not elute during the water treatment operation.
  • polyvinyl alcohol, polyvinyl pyrrolidone, hydroxypropyl cellulose, polyethylene And glycols and saponified polyethylene-vinyl acetate copolymers for example, polyvinyl alcohol, polyvinyl pyrrolidone, hydroxypropyl cellulose, polyethylene And glycols and saponified polyethylene-vinyl acetate copolymers.
  • polyvinyl alcohol in particular, by using polyvinyl alcohol having a saponification degree of 99% or more, or by crosslinking polyvinyl alcohol having a saponification degree of 90% or more with the polyamide-based resin of the skin layer, It is preferable to use a structure that does not easily dissolve during water treatment.
  • At least one surface of the separation membrane of the hydrophilic polymer or the separation membrane after the hydrophilization treatment has a porous structure or non-porous structure having an average pore diameter of 1,000 nm or less, and is concentrated by increasing the permeation flow rate. From the viewpoint of improving the treatment efficiency, a porous structure having an average pore diameter of 1 to 500 nm is preferable.
  • the membrane element in the present invention includes the separation membrane for concentrating bubble liquid as described above.
  • the form of such a membrane element is not particularly limited, and examples thereof include a flat membrane type such as a frame and plate type, a spiral type, and a pleated type.
  • the separation membrane for concentrating bubble liquid is a hollow fiber membrane
  • a hollow fiber membrane element in which a plurality of hollow fiber membranes are bundled and one or both ends are sealed with a resin or the like is used.
  • spiral membrane elements are generally preferred from the relationship between pressure and flow efficiency.
  • the spiral membrane element includes a laminated body including a separation membrane 2, a supply-side flow path member 6, and a permeate-side flow path member 3, and a perforated central tube around which the laminated body is wound. 5 and a sealing portion 21 that prevents mixing of the supply-side flow path and the permeation-side flow path.
  • a plurality of separation membrane units including the separation membrane 2, the supply-side flow path material 6 and the permeation-side flow path material 3 are wound bodies R wound around the central tube 5. Indicates.
  • the sealing part 21 for preventing the mixing of the supply side flow path and the permeation side flow path is, for example, an envelope shape by overlapping the separation membrane 2 on both surfaces of the permeation side flow path material 3 and bonding the three sides.
  • the sealing portion 21 is formed on the sealing portion 21 on the outer peripheral side edge, the upstream side edge, and the downstream side edge.
  • the envelope film 4 is attached to the central tube 5 at its opening, and is wound spirally around the outer peripheral surface of the central tube 5 together with the net-like (net-like) supply-side flow path member 6 so that the wound body R becomes It is formed.
  • An upstream end member 10 such as a seal carrier is provided on the upstream side of the wound body R, and a downstream end member 20 such as a telescope prevention member is provided on the downstream side as necessary.
  • the supply liquid 7 (stock solution before concentration) is supplied from one end face side of the membrane element 1.
  • the supplied supply liquid 7 flows in a direction parallel to the axial direction A1 of the center tube 5 along the supply-side flow path member 6, and is discharged as a concentrated liquid 9 containing bubbles from the other end face side of the membrane element 1. Is done.
  • the permeated liquid 8 that has permeated the separation membrane 2 in the course of the supply liquid 7 flowing along the supply-side flow path material 6 passes through the aperture 5a along the permeation-side flow path material 3 as shown by the broken line arrows in the figure. It flows into the center tube 5 and is discharged from the end of the center tube 5. That is, the membrane element 1 has a structure in which the permeated liquid permeates the other membrane surface side of the separation membrane 2 while the supply liquid flows along one membrane surface of the separation membrane 2.
  • the channel material generally has a role of ensuring a gap for uniformly supplying fluid to the membrane surface.
  • a channel material for example, a net, a knitted fabric, a concavo-convex processed sheet or the like can be used, and a material having a maximum thickness of about 0.1 to 3 mm can be used as needed.
  • the pressure loss is low, and further, a material that causes an appropriate turbulent flow effect is preferable.
  • the channel material is installed on both sides of the separation membrane, but it is common to use different channel materials as the supply side channel material on the supply liquid side and the permeate side channel material on the permeate side. .
  • the supply-side channel material uses a coarse and thick net-like channel material, while the permeate-side channel material uses a fine woven or knitted channel material.
  • the supply channel material is provided on the inner surface side of the two-folded separation membrane, for example.
  • a network structure in which linear objects are generally arranged in a lattice can be preferably used.
  • a material to comprise Polyethylene, a polypropylene, etc. are used.
  • the thickness of the supply side channel material is generally 0.2 to 2.0 mm, preferably 0.5 to 1.0 mm.
  • the permeate-side channel material is provided on the outer surface side of the two-folded separation membrane, for example.
  • This permeation side channel material is required to support the pressure applied to the membrane from the back side of the membrane and secure a permeate channel.
  • a net or tricot knitted fabric made of polyethylene or polypropylene is used.
  • a tricot knitted fabric made of polyethylene terephthalate is particularly preferably used.
  • the center tube is not particularly limited as long as it is a perforated hollow tube having a plurality of small holes on the wall surface of the pipe (hollow tube). At the time of bubbling liquid concentration, the permeated liquid that has passed through the separation membrane enters the hollow tube through the hole in the wall surface, and forms a permeate-side flow path.
  • the length of the central tube is generally longer than the length of the element in the axial direction, but a central tube having a connection structure such as a plurality of divisions may be used.
  • a thermosetting resin or a thermoplastic resin is used.
  • the membrane module according to the present invention includes a membrane element including the separation membrane for concentrating bubble liquid as described above, and a container that accommodates the membrane element and forms a concentration side channel and a permeation side channel. is there.
  • the membrane module 30 shown in the present embodiment includes, for example, a spiral membrane element 1, a supply unit 32 that supplies the supply element 7, and a concentration unit 9 that discharges the concentrate 9, as shown in FIG. 3.
  • a container 31 having a liquid discharge part 33 and a permeate discharge part 34 for discharging the permeate 8.
  • the upstream end member 10 holds the sealing material 11, and the sealing material 11 is in pressure contact with the inner wall of the container 31, thereby leading the supply liquid 7 to the inside of the wound body R of the membrane element 1. It has become.
  • the concentrated liquid 9 that has flowed out from the inside of the wound body R flows with the concentrated liquid discharger 33 through the internal space of the container 31. Further, one end (the left end in FIG. 3) of the central tube 5 is closed, and the other end (the right end in FIG. 3) is connected to the permeate discharge part 34 of the container 31.
  • the central tubes 5 of the adjacent membrane elements 1 are connected to each other via a connecting member (not shown) or the like. With such a structure, the container 31 forms a concentration side channel and a permeation side channel.
  • a liquid containing bubbles having a diameter of less than 1 ⁇ m is supplied from the supply unit 32 as the supply liquid 7 in a state where the concentration side flow path is pressurized, so that the bubble liquid is separated from the bubble liquid concentration separation membrane.
  • the concentrated concentrate 9 can be discharged from the concentrated liquid discharge portion 33.
  • the permeated liquid 8 that has permeated through the bubble liquid concentrating separation membrane can be discharged from the permeated liquid discharging section 34.
  • the discharged permeate 8 does not contain bubbles (substantially only the liquid is separated).
  • the permeate 8 is not suitable for the properties of the separation membrane, permeate flow rate, processing efficiency of concentration, etc. May contain a small amount of bubbles.
  • the bubble liquid concentrating device of the present invention concentrates bubbles existing in the supply liquid by the separation membrane 2, and the supply side flow path (concentration side flow path) of the membrane module 30 is provided.
  • the bubble liquid is concentrated in a pressurized state.
  • a part of the supply liquid 7 is supplied when the supply liquid 7 is pressurized and supplied from the supply liquid tank 35 to the container 31 by the pump 37, as shown in FIG.
  • the pressure of the concentration side flow path can be adjusted by adjusting the flow rate with the valve 39 while circulating the concentrated liquid 9 through the pipe 41 and circulating the concentrated liquid 9 through the pipe 42. At that time, the pressure and flow rate can be measured by the pressure gauge 38 and the flow meter 40, respectively.
  • the permeate 8 is discharged to the permeate tank 43.
  • the piping 42 is preferably provided with a valve for adjusting the flow rate in order to facilitate pressure adjustment.
  • the pressure in the concentration side flow path is determined according to the permeation flux of the separation membrane, and may be 0.05 to 6 MPa, for example.
  • the average linear velocity of the supply liquid on the film surface is preferably 0.1 to 100 cm / second, more preferably 1 to 50 cm / second, from the viewpoint of suppressing the disappearance of bubbles. More preferably, it is 5 to 30 cm / sec. If the average linear velocity of the supply liquid is too low, the effect of suppressing the disappearance of bubbles is insufficient, and if it is too high, the pressure loss of the flow path increases and energy consumption increases, which is not preferable.
  • a plurality of hollow fiber membranes that are separation membranes 2 are bundled and sealed so that one end (the left end in FIG. 4) is closed with a closing member 15 such as resin,
  • a hollow fiber membrane element whose end (right end in FIG. 4) is sealed with a sealing member 16 such as resin can be used.
  • a sealing material 17 is interposed between the outer periphery of the sealing member 16 and the inner surface of the container 31.
  • a concentration side flow path is formed, and the supply liquid 7 is supplied from the supply part 32, whereby the concentrate 9 in which the bubble liquid is concentrated by the separation liquid for bubble liquid concentration is discharged from the concentrate discharge part 33.
  • the permeated liquid 8 that has permeated through the bubble liquid concentrating separation membrane can be discharged from the permeated liquid discharging section 34.
  • one end (left end in FIG. 4) is sealed so as to be closed with a closing member 15 such as a resin, but a plurality of hollow fiber membranes are arranged in a U-shape, It is also possible to provide a hollow fiber membrane element whose end is sealed so as to be opened by a sealing member 16 such as a resin.
  • a hollow fiber membrane element in which the end portions on both sides of the hollow fiber membrane are sealed so as to be opened with a sealing member 16 such as a resin.
  • the concentration side flow path and the permeation side flow path can be formed in the container 31 by interposing the sealing material 17 on the inner surface of the container 31.
  • the membrane module having such a structure it is possible to supply a liquid for concentrating bubble liquid not only to the outside of the hollow fiber membrane but also to the inside thereof.
  • the example of the bubble liquid concentrating device that concentrates the bubble liquid while circulating the liquid is shown.
  • the bubble liquid concentrating apparatus of the present invention can concentrate the bubble liquid in one pass. The method of performing may be used.
  • the concentrated liquid 9 is discharged by the pipe 41 through the valve 39,
  • the pressure in the concentration side channel can be adjusted.
  • the permeate 8 can be discharged while concentrating the bubble liquid.
  • the high-density fine bubble liquid generation apparatus of the present invention supplies the above-described bubble liquid concentration apparatus of the present invention and the supply liquid containing bubbles having a diameter of less than 1 ⁇ m to the bubble liquid concentration apparatus.
  • a bubble generating device 50 that performs the above-described operation.
  • the supply liquid may be supplied directly from the bubble generating device 50 to the bubble liquid concentrating device, or may be supplied after being stored in the supply liquid tank.
  • the bubble generation device 50 for example, the one described in detail in Japanese Patent Application Laid-Open No. 2014-155920 can be adopted.
  • FIG. 8 shows a longitudinal sectional view of an example of the bubble generating device 50.
  • the bubble generating device 50 mixes a gas and a liquid, and generates a liquid containing fine bubbles of the gas.
  • water is used as the target liquid 51 before mixing.
  • Air is used as the gas mixed with water.
  • the bubble generation device 50 includes a fine bubble generation nozzle 52, a pressurized liquid generation unit 53, a delivery pipe 54a, an auxiliary pipe 54b, a return pipe 54c, a pump 54d, and a liquid storage unit 55.
  • the target liquid 51 is stored in the liquid storage unit 55. By operating the bubble generating device 50, the target liquid 51 becomes the supply liquid.
  • the delivery pipe 54 a connects the pressurized liquid generation unit 53 and the fine bubble generation nozzle 52.
  • the pressurizing liquid generating unit 53 generates a pressurizing liquid 56 in which gas is dissolved under pressure, and supplies the pressurized liquid 56 to the fine bubble generating nozzle 52 through the delivery pipe 54a.
  • the outlet of the fine bubble generating nozzle 52 is located in the liquid storage unit 55, and the delivery pipe 54 a substantially connects the pressurized liquid generation unit 53 and the liquid storage unit 55.
  • the fine bubbles are generated in the target liquid 51 by ejecting the pressurized liquid 56 into the target liquid 51 from the fine bubble generating nozzle 52.
  • fine air bubbles are generated in the target liquid 51.
  • the auxiliary pipe 54b connects the pressurized liquid generator 53 and the liquid reservoir 55 in the same manner as the delivery pipe 54a.
  • the auxiliary pipe 54 b guides the liquid discharged together with the excess gas to the liquid storage unit 55 when the excess gas is separated by the pressurized liquid generation unit 53.
  • the return pipe 54c is provided with a pump 54d, and the target liquid 51 is returned from the liquid reservoir 55 to the pressurized liquid generator 53 via the return pipe 54c by the pump 54d.
  • the pressurized liquid generating unit 53 includes a mixing nozzle 57 and a pressurized liquid generating container 58. From the gas inlet of the mixing nozzle 57, air flows in through a regulator, a flow meter or the like. In the mixing nozzle 57, the liquid pumped by the pump 54 d and the air are mixed by the mixing nozzle 57 and ejected into the pressurized liquid generating container 58.
  • the pressurized liquid generating container 58 is pressurized by passing the pressurized liquid 56 through the shape of the fine bubble generating nozzle 52 and the fine bubble generating nozzle 52 described later (hereinafter referred to as “pressure”). "Pressurized environment”).
  • the fluid (hereinafter referred to as “mixed fluid 59”) in which the liquid and the gas ejected from the mixing nozzle 57 are mixed is flowed through the pressurized liquid generating container 58 in a pressurized environment. It becomes the pressurizing liquid 56 which melt
  • the mixing nozzle 57 includes a liquid inlet through which the liquid pumped by the pump 54d described above flows, a gas inlet through which gas flows, and a mixed fluid outlet through which the mixed fluid 59 is ejected.
  • the mixed fluid 59 is generated by mixing the liquid flowing in from the liquid inlet and the gas flowing in from the gas inlet.
  • Each of the liquid inlet, the gas inlet, and the mixed fluid outlet is substantially circular.
  • the cross section of the nozzle flow path from the liquid inlet to the mixed fluid outlet and the cross section of the gas flow path from the gas inlet to the nozzle flow path are also substantially circular.
  • the channel cross section means a cross section perpendicular to the central axis of a flow channel such as a nozzle flow channel or a gas flow channel, that is, a cross section perpendicular to the flow of fluid flowing through the flow channel.
  • a flow channel such as a nozzle flow channel or a gas flow channel
  • the area of the channel cross section is referred to as “channel area”.
  • the nozzle channel is a Venturi tube whose channel area becomes smaller at the middle of the channel.
  • the mixing nozzle 57 includes an introduction portion, a first taper portion, a throat portion, a gas mixing portion, a second taper portion, and a lead-out portion that are continuously arranged in order from the liquid inlet to the mixed fluid outlet. With.
  • the mixing nozzle 57 also includes a gas supply unit provided with a gas flow path therein.
  • the liquid flowing into the nozzle channel from the liquid inlet is accelerated in the throat and the static pressure is reduced.
  • the pressure in the nozzle channel is lower than the atmospheric pressure. Become. Thereby, gas is attracted
  • the mixed fluid 59 is decelerated at the second tapered portion and the outlet portion to increase the static pressure, and is ejected into the pressurized liquid generating container 58 through the mixed fluid ejection port.
  • the pressurized liquid generating container 58 includes a first channel 58a, a second channel 58b, a third channel 58c, a fourth channel 58d, 5 flow paths 58e.
  • the flow paths 58a to 58e are pipe lines extending in the horizontal direction, and the cross section perpendicular to the longitudinal direction of the flow paths 58a to 58e is substantially rectangular. In the present embodiment, the width of the flow paths 58a to 58e is about 40 mm.
  • a mixing nozzle 57 is attached to the upstream end portion of the first flow path 58a (that is, the left end portion in FIG. 8), and the mixed fluid 59 ejected from the mixing nozzle 57 is added It flows toward the right side in FIG. 8 under a pressure environment.
  • the mixed fluid 59 is ejected from the mixing nozzle 57 above the liquid level of the mixed fluid 59 in the first flow path 58a, and the mixed fluid 59 immediately after the ejection is discharged from the first flow path 58a. It directly collides with the liquid surface before colliding with the downstream wall surface (that is, the right wall surface in FIG. 8).
  • the length of the first flow path 58a is set so that the center of the mixed fluid outlet 57b of the mixing nozzle 57 and the lower surface of the first flow path 58a. It is preferable to make it larger than 7.5 times the vertical distance between the two.
  • a part or the whole of the mixed fluid ejection port 57b of the mixing nozzle 57 may be located below the liquid level of the mixed fluid 59 in the first flow path 58a.
  • a substantially circular opening 58o is provided on the lower surface of the downstream end portion of the first flow path 58a, and the mixed fluid 59 flowing through the first flow path 58a is directed to the second flow path 58b positioned below. It falls through the opening 58o. In this way, it falls to the first flow path 58a, the second flow path 58b, the third flow path 58c, and the fourth flow path 58d.
  • the mixed fluid 59 is divided into a liquid layer containing bubbles and a gas layer located thereabove.
  • the fourth flow path 58d it flows (i.e., falls) into the fifth flow path 58e positioned below through a substantially circular opening 58o provided on the lower surface of the downstream end.
  • the fifth flow path 58e unlike the first flow path 58a to the fourth flow path 58d, there is no gas layer, and the fifth flow path 58e is contained in the liquid filling the fifth flow path 58e. There are slight bubbles in the vicinity of the upper surface.
  • the flow paths 58a to 58e of the pressurizing liquid generating container 58 flow down from the top to the bottom while repeating the steps gradually (that is, the flow in the horizontal direction and the flow in the downward direction are reduced).
  • the gas is gradually dissolved in the liquid under pressure.
  • the concentration of the gas dissolved in the liquid is substantially equal to 60% to 90% of the (saturated) solubility of the gas under a pressurized environment.
  • dissolved in the liquid exists as a bubble of the magnitude
  • the pressurized liquid generating container 58 further includes a surplus gas separation part 58f extending upward from the upper surface on the downstream side of the fifth flow path 58e, and the surplus gas separation part 58f is filled with the mixed fluid 59.
  • the cross section perpendicular to the vertical direction of the surplus gas separation portion 58f is substantially rectangular, and the upper end portion of the surplus gas separation portion 58f is connected to the auxiliary pipe 54b via a pressure adjusting throttle portion 58g.
  • the bubbles of the mixed fluid 59 flowing through the fifth flow path 58e rise in the surplus gas separation portion 58f and flow into the auxiliary pipe 54b together with a part of the mixed fluid 59.
  • the excess gas of the mixed fluid 59 is separated together with a part of the mixed fluid 59, thereby generating a pressurized liquid 56 substantially free of bubbles having a size that can be easily visually recognized. It is sent to a delivery pipe 54a connected to the downstream end of the five flow path 58e.
  • the pressurized liquid 56 dissolves a gas that is about twice or more the gas (saturated) solubility under atmospheric pressure.
  • the liquid of the mixed fluid 59 flowing through the flow paths 58a to 58e in the pressurized liquid generating container 58 can be regarded as the pressurized liquid 56 that is being generated.
  • the mixed fluid 59 that has flowed into the auxiliary pipe 54 b is guided to the target liquid 51 in the liquid reservoir 55.
  • the auxiliary pipe 54b functions as an auxiliary flow path for preventing a decrease in the target liquid 51 when the pump 54d is operated for a long time.
  • An exhaust valve 61 is also provided above the first flow path 58a.
  • the exhaust valve 61 is opened when the pump 54 d is stopped, and prevents the mixed fluid 59 from flowing back to the mixing nozzle 57.
  • the fine bubble generating nozzle 52 includes an introduction portion, a taper portion, and a throat portion that are sequentially arranged from the pressurized liquid inflow port toward the pressurized liquid ejection port.
  • the flow channel area is substantially constant at each position in the central axis direction of the nozzle flow channel 0.
  • the flow path area gradually decreases in the direction in which the pressurized liquid 56 flows (that is, toward the downstream side).
  • the inner surface of the tapered portion is a part of a substantially conical surface centered on the central axis of the nozzle channel. In the cross section including the central axis, the angle formed by the inner surface of the tapered portion is preferably 10 ° or more and 90 ° or less.
  • the throat communicates with the tapered part and the pressurized liquid spout.
  • the inner surface of the throat is a substantially cylindrical surface, and the channel area is substantially constant at the throat.
  • the diameter of the cross section of the channel in the throat is the smallest in the nozzle channel, and the channel area of the throat is the smallest in the nozzle channel.
  • the structure of the bubble generating device 50 may be variously changed, and further, a structure having a different structure may be used.
  • the fine bubble generating nozzle 52 may include a plurality of pressurized liquid ejection ports.
  • a pressure regulating valve may be provided between the fine bubble generating nozzle 52 and the pressurized liquid generating unit 53, and the pressure applied to the fine bubble generating nozzle 52 may be kept constant with high accuracy.
  • the cross-sectional shape of the flow path of the pressurized liquid generating container 58 may be circular. Other means such as mechanical stirring may be used for mixing the gas and the liquid.
  • the pipe 41 in FIG. 7 may be connected to the return pipe 54 c of the bubble generating device 50 in FIG. 8 so that the concentrate 9 is supplied again to the mixing nozzle 57. Further, the pipe 41 may be circulated to the liquid storage unit 55 of the bubble generating device 50. In this case, utilizing the fact that the concentrated flow path that has been in a pressurized state is depressurized, a fine bubble generating nozzle (not shown) is provided on the liquid storage section 55 side of the pipe 41 to depressurize, and the concentrated liquid 9 These bubbles may be further refined by a shearing force, and a fine bubble generating nozzle may be arranged in place of the valve 39 for bringing the concentration side flow path into a pressurized state.
  • Example of production of separation membrane A mixture of 18.3% by weight of polysulfone (manufactured by Solvay Advanced Polymers, P-3500) and 81.7% by weight of dimethylformamide on a nonwoven fabric made of polyester (Awa Paper Co., Ltd., 70 g / m 2 , thickness 90 ⁇ m). The liquid was applied. Thereafter, the polyester nonwoven fabric coated with the mixed solution was immersed in pure water at 20 ° C., and further immersed in pure water at 45 ° C. Thus, a polysulfone porous membrane having a thickness of about 130 ⁇ m was obtained.
  • the separation membrane here is an asymmetric membrane with different average pore sizes on both sides of the membrane, and the average pore size on the surface with the smaller pore size was 20 nm.
  • the average pore diameter was measured by reading from the surface observation of SEM (hereinafter the same).
  • Example 1 The polysulfone porous membrane obtained in the preparation example of the separation membrane was taken out after being immersed in an aqueous methacrylic acid solution (concentration 80 wt%), accelerated voltage 250 kV, irradiation dose 30 kGy, under nitrogen atmosphere (oxygen concentration 300 ppm or less), Electron beam irradiation was performed at room temperature, and methacrylic acid was graft-polymerized on the base material. Next, in order to remove the substrate and unreacted methacrylic acid monomer and polymer, immersion washing was performed for 2 hours in warm water at 60 ° C., followed by drying for 2 hours in a dryer at 40 ° C. Separation membrane (shown as “graft membrane” in Table 1 below) was obtained. The average pore diameter of the surface of the separation membrane having the smaller pore diameter was 20 nm.
  • aqueous solution (A) was prepared by mixing 3.0 g of m-phenylenediamine, 0.15 g of sodium lauryl sulfate, 6.0 g of benzenesulfonic acid, 3.0 g of triethylamine, and 87.85 g of water.
  • the aqueous solution (A) was applied on the polysulfone porous membrane obtained in the production example of the separation membrane, and the excess amine aqueous solution was removed.
  • an isooctane solution containing 0.2% by weight of trimesic acid chloride was further applied. After that, the excess isooctane solution is removed and held in a dryer at 100 ° C. for 2 minutes to form a polyamide skin layer (thickness: about 200 nm, non-porous structure) on the separation membrane.
  • a separation membrane for bubbling liquid concentration of Example 2 (shown as “coating membrane” in Table 1 described later) was obtained.
  • the produced flat membrane-shaped separation membranes for concentrating bubbles in Examples 1 and 2 and Comparative Example 1 were cut into a predetermined shape and size, and a flat membrane evaluation cell (C10-T, manufactured by Nitto Denko Corporation) was cut. ).
  • 4L of ultra fine bubble water (moderate diameter of bubbles is 0.1 ⁇ m and number density is 100 million / mL) generated by an ultra fine bubble generator (FEC1N-02, manufactured by IDEC Corporation)
  • the tank was prepared, and ultrafine bubble raw water was supplied at a pressure of 0.5 MPa and a flow rate of 1 L / min to the side having a small pore diameter (separation surface side) of the separation membrane for bubbling liquid concentration.
  • filtration was performed while circulating the ultrafine bubble raw water until the raw water tank reached 0.4 L to obtain a 10-fold concentrated liquid.
  • the number density of the ultra fine bubbles contained in the ultra fine bubble raw water and the 10-fold concentrated liquid was measured with a nanoparticle analyzer (Nanosite, NS500), and the increase rate of the number density of the ultra fine bubbles was calculated.
  • Table 1 shows the measurement results of the above measurements of the bubble liquid concentrating separation membranes according to Examples 1 and 2 and Comparative Example 1.
  • Example 3 the polysulfone porous membrane (ungrafted product) obtained in the separation membrane preparation example was used for surface treatment (coating, product name KM-118, manufactured by Kuraray Co., Ltd.). Except for the above, a separation membrane for concentrating bubble liquid (bubble contact angle 155 °) was prepared in the same manner as in Example 1, and the UFB number density before and after concentration was measured. As a result, the rate of increase in UFB number density upon 10-fold concentration was 3.7 times. The coating with polyvinyl alcohol was performed as follows.
  • the polysulfone porous membrane (ungrafted product) obtained in the preparation example of the separation membrane was dipped in a 10% by weight isopropyl alcohol aqueous solution to be in a wet state, and then 0.05% by weight polyvinyl alcohol on the polysulfone membrane side.
  • the aqueous solution was applied and dried in an oven at 80 ° C.
  • Hydrophobic polyethersulfone separation membrane (average pore size 10 nm, contact angle 75 °), polyvinylidene fluoride separation membrane (average pore size 500 nm, contact angle 56 °), epoxy resin separation membrane (average pore size 50 nm, contact angle 110) Were used as a separation membrane for bubbling liquid concentration without any surface treatment.
  • the increase rate of the UFB number density at the time of concentration 10 to 50 times was less than 2 times.

Abstract

The purpose of the present invention is to provide: a bubble liquid concentration device capable of obtaining a liquid including a high concentration of bubbles; and a device for generating a highly dense fine bubble liquid which uses same. This bubble liquid concentration device uses a separation membrane 2 to achieve a high concentration of bubbles in a bubble-containing supply liquid 7. The bubble liquid concentration device is characterized in that at least one surface of the separation membrane 2 has a bubble contact angle in water of at least 140˚. The bubble liquid concentration device is preferably used when concentrating a liquid which is present in the supply liquid 7, and which includes bubbles having a diameter of less than 1 µm.

Description

気泡液濃縮装置、及び高密度微細気泡液生成装置Bubble liquid concentrator and high density fine bubble liquid generator
　本発明は、分離膜により気泡を含有した供給液中の気泡を高濃度化する気泡液濃縮装置、及びこれを用いた高密度微細気泡液生成装置に関し、特に、液体中に存在する直径１μｍ未満の気泡（ウルトラファインバブル、ＵＦＢ）を高濃度化する技術として有用である。 The present invention relates to a bubble liquid concentrating device for increasing the concentration of bubbles in a supply liquid containing bubbles by a separation membrane, and a high-density fine bubble liquid generating device using the same, and in particular, a diameter of less than 1 μm existing in a liquid. This is useful as a technique for increasing the concentration of bubbles (ultra fine bubbles, UFB).
　近年、長期にわたり安定なウルトラファインバブルを含む水を生成する技術の研究が盛んに行われている。例えば、非特許文献１には、ウルトラファインバブルを多量に生成する装置が開示されている。また、非特許文献２では、ウルトラファインバブルが水中に安定的に存在する点について報告されている。 In recent years, research on technologies for generating water containing ultrafine bubbles that are stable over a long period of time has been actively conducted. For example, Non-Patent Document 1 discloses an apparatus that generates a large amount of ultrafine bubbles. Moreover, in the nonpatent literature 2, it is reported about the ultra fine bubble stably existing in water.
　また、ウルトラファインバブルを生成する方法としても種々の方法が存在し、例えば、特許文献１の微細気泡発生装置では、流体旋回室内において気体と液体とが混合された混合流体を高速に旋回させ、旋回流に発生する剪断力により気泡が微細化される。 In addition, there are various methods for generating ultra fine bubbles. For example, in the fine bubble generating device of Patent Document 1, a mixed fluid in which a gas and a liquid are mixed in a fluid swirl chamber is swirled at a high speed. Bubbles are refined by the shearing force generated in the swirling flow.
　しかし、ウルトラファインバブルを含む水は、機械的に水と空気とを混合することにより生成されるため、微細気泡の生成量は、０．１億個／ｍＬ～１０億個／ｍＬ程度であり、微細気泡を含む液体の用途の研究や、微細気泡を含む液体の取り扱いの効率化のためには、微細気泡の高密度化が重要であった。 However, since water containing ultrafine bubbles is generated by mechanically mixing water and air, the amount of fine bubbles generated is about 10 million / mL to 1 billion / mL. In order to study the use of liquids containing fine bubbles and to improve the efficiency of handling liquids containing fine bubbles, it is important to increase the density of fine bubbles.
　このため、特許文献２には、微細気泡の密度が高い液体を容易に生成することを目的として、直径が２００ｎｍより大きい微細気泡を通さない濾過フィルタに、微細気泡を含む液体の一部を透過させ、その液体の残部である高密度微細気泡液を得る高密度微細気泡液生成方法が、開示されている。ただし、特許文献２では濾過フィルタの孔径について言及されているものの、その材質等については開示されていない。 For this reason, Patent Document 2 discloses that a part of the liquid containing fine bubbles is transmitted through a filtration filter that does not pass fine bubbles having a diameter larger than 200 nm for the purpose of easily generating a liquid having a high density of fine bubbles. And a method for producing a high-density microbubble liquid that obtains a high-density microbubble liquid that is the remainder of the liquid is disclosed. However, Patent Document 2 mentions the pore diameter of the filter, but does not disclose the material or the like.
特許第４１２９２９０号公報Japanese Patent No. 4129290 特開２０１４－１５５９２０号公報JP 2014-155920 A
　しかしながら、特許文献２の高密度微細気泡液生成方法のように、分離膜として通常使用される濾過フィルタを用いた場合、気泡液の濃縮の際に、膜との接触により気泡が消失し易いため、供給した液中の気泡の総量に対して、濃縮後の気泡の総量が大幅に減少することが判明した。例えば、後述するように、分離膜として汎用されているポリスルホン製のＵＦ膜を使用した場合（比較例１参照）、原液を１０倍に濃縮しても、殆どの気泡が消失することによって、高濃度の気泡含有液を得ることができないという問題があった。 However, when a filtration filter usually used as a separation membrane is used as in the high-density fine bubble liquid generation method of Patent Document 2, bubbles are likely to disappear due to contact with the membrane when the bubble liquid is concentrated. The total amount of bubbles after concentration was found to be significantly reduced relative to the total amount of bubbles in the supplied liquid. For example, as will be described later, when a polysulfone UF membrane that is widely used as a separation membrane is used (see Comparative Example 1), even if the stock solution is concentrated 10 times, most bubbles disappear, There was a problem that a bubble-containing liquid having a concentration could not be obtained.
　そこで、本発明の目的は、高濃度の気泡含有液を得ることができる気泡液濃縮装置、及びこれを用いた高密度微細気泡液生成装置を提供することにある。 Therefore, an object of the present invention is to provide a bubble liquid concentrating device capable of obtaining a high-concentration bubble-containing liquid and a high-density fine bubble liquid generating apparatus using the same.
　本発明者らは、気泡液の濃縮に使用する膜の材質や表面特性について鋭意検討した結果、水中において気泡の接線方向と分離膜の表面との成す接触角（以下、気泡接触角という。）が１４０°以上である分離膜を使用することで、上記目的が達成できることを見出し、本発明を完成するに至った。 As a result of intensive studies on the material and surface characteristics of the membrane used for concentrating the bubble liquid, the present inventors have found that the contact angle between the tangential direction of the bubble and the surface of the separation membrane in water (hereinafter referred to as the bubble contact angle). It was found that the above-mentioned object can be achieved by using a separation membrane having an angle of 140 ° or more, and the present invention has been completed.
　即ち、本発明の気泡液濃縮装置は、分離膜により気泡を含有した供給液中の気泡を高濃度化する気泡液濃縮装置において、前記分離膜が、少なくとも一方の表面について、水中における気泡接触角が１４０°以上であることを特徴とする。 That is, the bubble liquid concentrating device of the present invention is a bubble liquid concentrating device for increasing the concentration of bubbles in a supply liquid containing bubbles by a separation membrane, wherein the separation membrane has a bubble contact angle in water with respect to at least one surface. Is 140 ° or more.
　本発明の気泡液濃縮装置によると、濃縮に用いる分離膜の表面の気泡接触角が１４０°以上であるため、膜面に気泡が付着しにくくなる。つまり、図１に示すように、水中における気泡接触角１０４°（図１ａ）の場合と気泡接触角１６７°（図１ｃ）の場合とでは、気泡の付着状態が大きく異なり、後者の方が膜面に気泡が付着しにくくなることで、気泡が消失するのを抑制しつつ、液体を透過させることができると考えられる。その結果、気泡液濃縮の際に膜との接触により気泡が消失するのを抑制することができ、高濃度の気泡含有液を得ることができる。 According to the bubble liquid concentrating device of the present invention, since the bubble contact angle on the surface of the separation membrane used for concentration is 140 ° or more, it is difficult for bubbles to adhere to the membrane surface. That is, as shown in FIG. 1, the bubble adhesion state is greatly different between the case where the bubble contact angle in water is 104 ° (FIG. 1a) and the case where the bubble contact angle is 167 ° (FIG. 1c). It is considered that the liquid can permeate while suppressing the disappearance of the bubbles by making the bubbles less likely to adhere to the surface. As a result, it is possible to suppress the disappearance of bubbles due to contact with the membrane during the bubble liquid concentration, and a high-concentration bubble-containing liquid can be obtained.
　特に、本発明では、前記供給液に、直径１μｍ未満の気泡が含まれていることが好ましい。分離膜表面の気泡接触角が１４０°以上であると、直径１μｍ未満の微細気泡に対しても、膜面に気泡を付着しにくくすることができ、効率良く気泡を分離して濃縮することができる。 In particular, in the present invention, it is preferable that the supply liquid contains bubbles having a diameter of less than 1 μm. When the bubble contact angle on the surface of the separation membrane is 140 ° or more, it is possible to make it difficult to attach bubbles to the membrane surface even for fine bubbles having a diameter of less than 1 μm, and to efficiently separate and concentrate the bubbles. it can.
　上記において、前記分離膜は、前記一方の表面が、平均孔径１，０００ｎｍ以下の多孔質構造、又は非多孔質構造であることが好ましい。このような平均孔径であると、直径１μｍ未満の気泡を効率良く分離して濃縮することができる。 In the above, the one surface of the separation membrane preferably has a porous structure having an average pore diameter of 1,000 nm or less or a non-porous structure. With such an average pore diameter, bubbles having a diameter of less than 1 μm can be efficiently separated and concentrated.
　また、前記一方の表面に、親水性を有するポリマー多孔質層又は非多孔質層を有することが好ましい。親水性を有するポリマー多孔質層又は非多孔質層を有することにより、水中における気泡接触角が１４０°以上の分離膜が得られ易くなる。 Further, it is preferable that a hydrophilic polymer porous layer or a non-porous layer is provided on the one surface. By having a polymer porous layer or non-porous layer having hydrophilicity, a separation membrane having a bubble contact angle in water of 140 ° or more is easily obtained.
　本発明の気泡液濃縮装置は、前記分離膜を有する膜エレメントと、その膜エレメントを収容して濃縮側流路と透過側流路とを形成する容器とを含む膜モジュールを備えることが好ましい。このように、膜エレメントを容器に収容する構造にすることで、膜エレメントの交換も容易になり、従来の膜分離装置の圧力容器等を利用することができる。 The bubble liquid concentrating device of the present invention preferably includes a membrane module including a membrane element having the separation membrane and a container that accommodates the membrane element and forms a concentration side channel and a permeation side channel. As described above, by adopting a structure in which the membrane element is accommodated in the container, the exchange of the membrane element is facilitated, and the pressure vessel or the like of the conventional membrane separation apparatus can be used.
　前記膜エレメントは、前記分離膜の一方の膜面に沿って前記供給液が流動しながら、透過液を前記分離膜の他方の膜面側に透過させる構造であることが好ましい。このようなクロスフロー方式の構造を採用することで、より効果的に膜面に気泡が付着するのを防止でき、気泡が消失するのをより確実に抑制することができる。 The membrane element preferably has a structure that allows the permeate to permeate the other membrane surface of the separation membrane while the supply fluid flows along one membrane surface of the separation membrane. By adopting such a cross-flow structure, it is possible to more effectively prevent bubbles from adhering to the film surface and to more reliably suppress the disappearance of the bubbles.
　また、前記膜モジュールから排出された濃縮液を供給液に戻す循環流路を備えることが好ましい。このような循環流路を備えることで、供給液の流速を高めて、より効果的に膜面に気泡が付着するのを防止できるようになる。 Further, it is preferable to provide a circulation channel for returning the concentrated liquid discharged from the membrane module to the supply liquid. By providing such a circulation channel, it is possible to increase the flow rate of the supply liquid and prevent bubbles from adhering to the membrane surface more effectively.
　一方、本発明の高密度微細気泡液生成装置は、いずれかに記載の気泡液濃縮装置と、その気泡液濃縮装置に直径１μｍ未満の気泡を含む供給液を供給する気泡生成装置と、を備えることを特徴とする。本発明の高密度微細気泡液生成装置によると、気泡液濃縮装置が、少なくとも一方の表面について、水中における気泡接触角が１４０°以上である分離膜を備えるため、気泡液濃縮の際に膜との接触により気泡が消失するのを抑制することができ、高濃度の気泡含有液を得ることができる。 On the other hand, a high-density fine bubble liquid generator of the present invention includes any of the bubble liquid concentrators and a bubble generator that supplies a supply liquid containing bubbles having a diameter of less than 1 μm to the bubble liquid concentrator. It is characterized by that. According to the high-density fine bubble liquid generator of the present invention, the bubble liquid concentrator includes a separation membrane having a bubble contact angle in water of 140 ° or more on at least one surface. It is possible to suppress the disappearance of bubbles due to the contact, and a high-concentration bubble-containing liquid can be obtained.
　なお、気泡生成装置で生成した供給液には直径が１μｍ未満の気泡だけではなく、直径が１μｍ以上から５００ｎｍ以下の気泡も含まれている。したがって、本発明の気泡液濃縮装置により得た気泡含有液にも直径１μｍ以上の気泡が含まれていてもよい。 Note that the supply liquid generated by the bubble generator includes not only bubbles having a diameter of less than 1 μm, but also bubbles having a diameter of 1 μm or more to 500 nm or less. Therefore, the bubble-containing liquid obtained by the bubble liquid concentrating device of the present invention may contain bubbles having a diameter of 1 μm or more.
水中における気泡接触角を説明するための写真であり、（ａ）が気泡接触角１０４°、（ｂ）が気泡接触角１３５°、（ｃ）が気泡接触角１６７°の場合を示す。It is a photograph for explaining the bubble contact angle in water, and shows a case where (a) is a bubble contact angle of 104 °, (b) is a bubble contact angle of 135 °, and (c) is a bubble contact angle of 167 °. 本発明における膜エレメントの一例を示す分解斜視図である。It is a disassembled perspective view which shows an example of the membrane element in this invention. 本発明における膜モジュールの一例を示す縦断面図である。It is a longitudinal cross-sectional view which shows an example of the membrane module in this invention. 本発明における膜モジュールの他の例を示す縦断面図である。It is a longitudinal cross-sectional view which shows the other example of the membrane module in this invention. 本発明の気泡液濃縮装置の一例を示す概略構成図である。It is a schematic block diagram which shows an example of the bubble liquid concentration apparatus of this invention. 本発明の気泡液濃縮装置の他の例を示す概略構成図である。It is a schematic block diagram which shows the other example of the bubble liquid concentration apparatus of this invention. 本発明の高密度微細気泡液生成装置の一例を示す概略構成図である。It is a schematic block diagram which shows an example of the high-density fine bubble liquid production | generation apparatus of this invention. 本発明の高密度微細気泡液生成装置の気泡生成装置の例を示す縦断面図である。It is a longitudinal cross-sectional view which shows the example of the bubble production | generation apparatus of the high-density fine bubble liquid production | generation apparatus of this invention.
　本発明の気泡液濃縮装置は、分離膜により気泡を含有した供給液中の気泡を高濃度化する気泡液濃縮装置において、前記分離膜が、少なくとも一方の表面について、水中における気泡接触角が１４０°以上であることを特徴とする。つまり、本発明の気泡液濃縮装置は、例えば図５に示すように、気泡液濃縮用の分離膜２を備えている。また、本発明の気泡液濃縮装置は、例えば図３に示すように、分離膜２を有する膜エレメント１と、その膜エレメント１を収容して濃縮側流路と透過側流路とを形成する容器３１とを含む膜モジュール３０を備えることが好ましい。まず、気泡液濃縮用分離膜について詳述する。 The bubble liquid concentrating device of the present invention is a bubble liquid concentrating device for increasing the concentration of bubbles in a supply liquid containing bubbles by a separation membrane, wherein the separation membrane has a bubble contact angle in water of at least one surface of 140. It is characterized by being at least °. That is, the bubble liquid concentrating device of the present invention includes a separation membrane 2 for condensing bubble liquid, for example, as shown in FIG. In addition, the bubble liquid concentrating device of the present invention, as shown in FIG. 3, for example, forms a membrane element 1 having a separation membrane 2 and the membrane element 1 to form a concentration side channel and a permeation side channel. A membrane module 30 including the container 31 is preferably provided. First, the separation membrane for concentrating bubble liquid will be described in detail.
　（気泡液濃縮用分離膜）
　本発明における気泡液濃縮用分離膜は、例えば直径１００μｍ以下の気泡を含有した液体（気泡液）を濃縮して、含有される気泡を高濃度化する際に使用するものであり、特に、直径１μｍ未満の気泡を含有する液体を濃縮する際に使用することが好ましい。 (Separation membrane for bubble liquid concentration)
The separation membrane for concentrating bubble liquid in the present invention is used, for example, when concentrating a liquid (bubble liquid) containing bubbles having a diameter of 100 μm or less to increase the concentration of contained bubbles. It is preferably used when concentrating a liquid containing bubbles of less than 1 μm.
　液体中に存在する直径１μｍ未満の気泡は、ウルトラファインバブル（ＵＦＢ）と呼ばれ、直径がより大きいマイクロバルブと比較して、液体中で長期にわたり安定し、液体が透明な性質を有する。 Bubbles with a diameter of less than 1 μm present in the liquid are called ultra fine bubbles (UFB), and have a property that the liquid is stable for a long period of time and is transparent in comparison with a microvalve having a larger diameter.
　また、ＵＦＢは、気体富化、界面活性、圧壊、帯電、比表面積増加、などの特性を有しており、枚葉剥離、乳化、香気封入、鮮度保持などが可能である。このため、ＵＦＢは、半導体装置、フラットパネルディスプレイ、電子機器、太陽電池、二次電池などの用途の他、食品、飲料、化粧品、薬品、医療、植物栽培、新機能材料、放射性物質除去等の種々の用途に使用可能である。 Moreover, UFB has characteristics such as gas enrichment, surface activity, crushing, charging, specific surface area increase, etc., and can perform sheet-fed peeling, emulsification, aroma encapsulation, freshness maintenance, and the like. For this reason, UFB is used for semiconductor devices, flat panel displays, electronic devices, solar cells, secondary batteries, food, beverages, cosmetics, medicines, medicine, plant cultivation, new functional materials, removal of radioactive substances, etc. It can be used for various purposes.
　ＵＦＢは、種々の方法で生成することが可能であり、例えば、流体旋回室内において気体と液体とが混合された混合流体を高速に旋回させ、旋回流に発生する剪断力により気泡を微細化する方法が挙げられる。 UFB can be generated by various methods. For example, a mixed fluid in which a gas and a liquid are mixed in a fluid swirl chamber is swirled at high speed, and bubbles are refined by shearing force generated in the swirl flow. A method is mentioned.
　気泡を有する液体としては、水、アルコール水溶液、オゾン水、酸性水溶液、アルカリ水溶液、界面活性剤水溶液などが挙げられる。 Examples of the liquid having bubbles include water, an aqueous alcohol solution, ozone water, an acidic aqueous solution, an alkaline aqueous solution, and a surfactant aqueous solution.
　ＵＦＢの平均直径としては、上記のような機能を発現させる観点から、通常１μｍ未満であり、０．０１～０．５μｍが好ましい。また、濃縮前の液体中の数密度は、濃縮後の数密度を高める観点から、少なくとも０．３億個／ｍＬ以上が好ましく、１億個／ｍＬ～１０億個／ｍＬであることがより好ましい。 The average diameter of UFB is usually less than 1 μm and preferably 0.01 to 0.5 μm from the viewpoint of developing the above functions. Further, the number density in the liquid before concentration is preferably at least 30 million / mL or more from the viewpoint of increasing the number density after concentration, more preferably 100 million / mL to 1 billion / mL. preferable.
　本発明における気泡液濃縮用分離膜は、少なくとも一方の表面について、水中における気泡接触角が１４０°以上であることを特徴とするが、両方の表面が気泡接触角１４０°以上であってもよい。一方の表面のみが気泡接触角１４０°以上である場合、その表面が供給液側（濃縮前の原液）に配置され、他方の面から透過液側に配置される。 The separation membrane for concentrating bubble liquid in the present invention is characterized in that at least one surface has a bubble contact angle in water of 140 ° or more, but both surfaces may have a bubble contact angle of 140 ° or more. . When only one surface has a bubble contact angle of 140 ° or more, the surface is disposed on the supply liquid side (the undiluted stock solution) and disposed on the permeate side from the other surface.
　水中における気泡接触角は、１４０°以上１８０°未満であるが、気泡液濃縮の際に膜との接触により気泡が消失するのをより確実に抑制する観点から、１４５°以上が好ましく、１５０°以上がより好ましく、１６０以上が最も好ましい。また、水中における気泡接触角は、分離膜の製造のし易さ等の観点から、１７８°以下が好ましく、１７５°以下がより好ましく、１７０°以下が最も好ましい。 The bubble contact angle in water is 140 ° or more and less than 180 °, but it is preferably 145 ° or more and 150 ° from the viewpoint of more reliably suppressing the disappearance of bubbles due to contact with the membrane during bubble liquid concentration. The above is more preferable, and 160 or more is most preferable. In addition, the bubble contact angle in water is preferably 178 ° or less, more preferably 175 ° or less, and most preferably 170 ° or less from the viewpoint of ease of production of the separation membrane.
　このような気泡接触角を有する分離膜は、疎水性のポリマー多孔質層の少なくとも表面を親水化処理する方法や、親水性のポリマーで分離膜を製造することで得ることができる。 The separation membrane having such a bubble contact angle can be obtained by a method of hydrophilizing at least the surface of the hydrophobic polymer porous layer, or by producing a separation membrane with a hydrophilic polymer.
　後者のように、親水性のポリマーで分離膜を製造する場合、例えば、セルロース系樹脂、ポリアミド系樹脂、ポリビニルアルコール系樹脂、エポキシ樹脂、を用いる方法や、更に架橋構造を導入することで、上記の気泡接触角を有する分離膜を得ることができる。このような分離膜としては、分離膜の耐久性、耐圧性、透過流量、などの観点から、親水性のポリマー多孔質層が不織布層の片面に形成されているものが好ましい。また、本発明では、平膜に限らず、中空糸膜、チューブ状膜も使用することができる。 When the separation membrane is produced with a hydrophilic polymer like the latter, for example, by using a cellulose resin, a polyamide resin, a polyvinyl alcohol resin, an epoxy resin, or by introducing a crosslinked structure, A separation membrane having a bubble contact angle of can be obtained. Such a separation membrane is preferably one in which a hydrophilic polymer porous layer is formed on one side of a nonwoven fabric layer from the viewpoint of durability, pressure resistance, permeation flow rate, etc. of the separation membrane. In the present invention, not only a flat membrane but also a hollow fiber membrane and a tubular membrane can be used.
　但し、分離膜の耐久性、製造性、などの観点から、疎水性のポリマー多孔質層の表面を親水化処理する方法が好ましい。特に、親水化処理が、親水性物質のコーティング、又は親水性ポリマーのグラフトにより行なわれていることが好ましい。 However, from the viewpoint of durability and manufacturability of the separation membrane, a method of hydrophilizing the surface of the hydrophobic polymer porous layer is preferable. In particular, it is preferable that the hydrophilic treatment is performed by coating with a hydrophilic substance or grafting with a hydrophilic polymer.
　親水化処理に用いる分離膜としては、疎水性のポリマー多孔質層を有するものが挙げられ、分離膜の耐久性、耐圧性、透過流量、などの観点から、ポリマー多孔質層が不織布層の片面に形成されているものが好ましい。また、本発明では、平膜に限らず、中空糸膜、チューブ状膜も使用することができる。 Examples of the separation membrane used for the hydrophilization treatment include those having a hydrophobic polymer porous layer. From the viewpoint of the durability of the separation membrane, pressure resistance, permeation flow rate, etc., the polymer porous layer is one side of the nonwoven fabric layer. What is formed in is preferable. In the present invention, not only a flat membrane but also a hollow fiber membrane and a tubular membrane can be used.
　疎水性のポリマーとしては、例えば、ポリスルホン、ポリエーテルスルホンに例示されるポリアリールエーテルスルホン、ポリイミド、ポリフッ化ビニリデン、エポキシ樹脂、ポリエチレン、ポリプロピレン、フッ素樹脂など種々のものをあげることができる。特に化学的、機械的、熱的に安定である点からポリスルホン、ポリアリールエーテルスルホンが好ましい。 Examples of the hydrophobic polymer include various polymers such as polysulfone and polyarylethersulfone exemplified by polyethersulfone, polyimide, polyvinylidene fluoride, epoxy resin, polyethylene, polypropylene, and fluororesin. In particular, polysulfone and polyarylethersulfone are preferable because they are chemically, mechanically and thermally stable.
　親水化処理に用いる分離膜としては、膜の両面で平均孔径が異なる非対称膜であっても、対称膜であってもよいが、濃縮時の処理効率の観点から、非対称膜であることが好ましい。 The separation membrane used for the hydrophilization treatment may be an asymmetric membrane having a different average pore size on both sides of the membrane or a symmetric membrane, but is preferably an asymmetric membrane from the viewpoint of treatment efficiency during concentration. .
　分離膜の平均孔径（孔径が小さい方の表面の平均孔径）は、親水化処理後の孔径、親水化処理のし易さ、などの観点から、０．００１～２μｍが好ましく、０．０５～１μｍがより好ましく、０．０１～０．４μｍが更に好ましい。 The average pore size of the separation membrane (the average pore size of the surface having the smaller pore size) is preferably 0.001 to 2 μm, preferably 0.05 to 2 μm, from the viewpoints of the pore size after the hydrophilic treatment and the ease of the hydrophilic treatment. 1 μm is more preferable, and 0.01 to 0.4 μm is even more preferable.
　分離膜又はポリマー多孔質層の厚みは、１０～３００μｍが好ましく、５０～２００μｍがより好ましい。不織布層の厚みは、３０～２００μｍが好ましく、５０～１５０μｍがより好ましい。 The thickness of the separation membrane or polymer porous layer is preferably 10 to 300 μm, more preferably 50 to 200 μm. The thickness of the nonwoven fabric layer is preferably 30 to 200 μm, more preferably 50 to 150 μm.
　不織布層としては、前記分離膜の分離性能および透過性能を保持しつつ、適度な機械強度を付与するものであれば特に限定されるものではなく、市販の不織布を用いることができる。この材料としては例えば、ポリオレフィン、ポリエステル、セルロースなどからなるものが用いられ、複数の素材を混合したものも使用することができる。特に成形性の点ではポリエステルを用いることが好ましい。また適宜、長繊維不織布や短繊維不織布を用いることができるが、ピンホール欠陥の原因となる微細な毛羽立ちや膜面の均一性の点から、長繊維不織布を好ましく用いることができる。また、このときの前記不織布層単体の通気度としては、これに限定されるものではないが、０．５～１０ｃｍ３／ｃｍ２・ｓ程度のものを用いることができ、１～５ｃｍ３／ｃｍ２・ｓ程度のものが好ましく用いられる。 The nonwoven fabric layer is not particularly limited as long as it provides an appropriate mechanical strength while maintaining the separation performance and permeation performance of the separation membrane, and a commercially available nonwoven fabric can be used. As this material, for example, a material made of polyolefin, polyester, cellulose or the like is used, and a material in which a plurality of materials are mixed can also be used. In particular, it is preferable to use polyester in terms of moldability. In addition, a long fiber nonwoven fabric or a short fiber nonwoven fabric can be used as appropriate, but a long fiber nonwoven fabric can be preferably used from the viewpoint of fine fuzz that causes pinhole defects and uniformity of the film surface. Further, the air permeability of the nonwoven fabric layer at this time is not limited to this, but it can be about 0.5 to 10 cm 3 / cm 2 · s, and 1 to 5 cm 3 / s. Those having a size of about cm 2 · s are preferably used.
　上記のような分離膜は、各種市販されており、親水性ポリマーの分離膜は、そのまま使用することができる。また、疎水性ポリマーの分離膜は、親水化処理に使用することができる。また、分離膜を公知の方法により製造することも可能である。 Various types of separation membranes as described above are commercially available, and hydrophilic polymer separation membranes can be used as they are. In addition, the hydrophobic polymer separation membrane can be used for hydrophilization treatment. It is also possible to manufacture the separation membrane by a known method.
　前記ポリマー多孔質層のポリマーが、ポリスルホンである場合の製造方法について例示する。ポリマー分離膜は一般に湿式法または乾湿式法と呼ばれる方法により製造できる。まず、ポリスルホンと溶媒及び各種添加剤を溶解した溶液準備工程と、前記溶液で不織布上を被覆する被覆工程と、この溶液中の溶媒を蒸発させてミクロ相分離を生じさせる乾燥工程と、水浴等の凝固浴に浸漬することで固定化する固定化工程を経て、不織布上のポリマー多孔質層を形成することができる。前記ポリマー多孔質層の厚さは、不織布層に含浸される割合も計算の上、前記溶液濃度及び被覆量を調整することで設定することができる。 An example of the production method when the polymer of the polymer porous layer is polysulfone will be described. The polymer separation membrane can be produced by a method generally called a wet method or a dry wet method. First, a solution preparation step in which polysulfone, a solvent and various additives are dissolved, a coating step in which the nonwoven fabric is coated with the solution, a drying step in which the solvent in the solution is evaporated to cause microphase separation, a water bath, etc. The polymer porous layer on the nonwoven fabric can be formed through an immobilization step of immobilization by dipping in a coagulation bath. The thickness of the polymer porous layer can be set by adjusting the solution concentration and the coating amount after calculating the ratio of impregnation into the nonwoven fabric layer.
　次ぎに、親水化処理について説明する。親水化処理は、親水性物質のコーティング、又は親水性ポリマーのグラフトにより行なうことが好ましいが、その他、親水性基の導入による表面処理、プラズマ処理、エキシマレーザー照射、コロナ放電処理等による表面処理、などによっても、親水化処理が可能である。 Next, the hydrophilic treatment will be described. The hydrophilization treatment is preferably performed by hydrophilic substance coating or hydrophilic polymer grafting. In addition, surface treatment by introduction of hydrophilic groups, plasma treatment, excimer laser irradiation, surface treatment by corona discharge treatment, The hydrophilization treatment is possible also by the above.
　親水性物質のコーティングには、親水性物質として低分子を用いる方法と、高分子を用いる方法があるが、低分子を用いて重合反応を行ない高分子化することも可能である。 There are two methods for coating a hydrophilic substance: a method using a low molecule as a hydrophilic substance and a method using a polymer, but it is also possible to polymerize by performing a polymerization reaction using a low molecule.
　高分子を用いる方法としては、ポリビニルアルコール、ポリエチレングリコール、ポリビニルピロリドン、ポリアクリル酸、ヒドロキシプロピルセルロース、等のポリマーを用いて、溶媒に溶解し、その溶液を分離膜に塗布又は含浸させた後、乾燥させる方法が挙げられる。その際、架橋剤等を用いて、ポリマー同士又は分離膜との間で架橋反応させることも可能である。 As a method using a polymer, a polymer such as polyvinyl alcohol, polyethylene glycol, polyvinyl pyrrolidone, polyacrylic acid, hydroxypropyl cellulose, etc. is dissolved in a solvent, and the solution is applied or impregnated on a separation membrane. The method of making it dry is mentioned. In that case, it is also possible to carry out a crosslinking reaction between the polymers or the separation membrane using a crosslinking agent or the like.
　また、親水性物質として低分子を用いる方法でも、ショ糖脂肪酸エステル、ソルビトール、グリセリンなどの多価アルコールや、ドデシルベンゼンスルホン酸ナトリウム、ドデシル硫酸ナトリウム、及びラウリル硫酸ナトリウム等の界面活性剤、乳酸ナトリウム、グリセリン等を用いて、溶媒に溶解し、その溶液を分離膜に塗布又は含浸させた後、乾燥させる方法が挙げられる。 In addition, even in the method using a low molecule as a hydrophilic substance, polyhydric alcohols such as sucrose fatty acid ester, sorbitol and glycerin, surfactants such as sodium dodecylbenzenesulfonate, sodium dodecylsulfate and sodium laurylsulfate, sodium lactate And a method of dissolving in a solvent using glycerin or the like, applying or impregnating the solution to a separation membrane, and then drying.
　また、分離膜との反応性を有する官能基を有する親水性物質を使用し、分離膜の間で反応させることも可能である。 It is also possible to use a hydrophilic substance having a functional group having reactivity with the separation membrane to cause a reaction between the separation membranes.
　親水性ポリマーをグラフトさせる場合、例えばビニル型の親水性モノマーが使用される。ビニル型の親水性モノマーとしては、アクリル酸、メタクリル酸、ヒドロキシメチルメタクリル酸、スルホエチルメタクリル酸、スチレンスルホン酸又はそれらのアルカリ金属塩などが使用できる。 When grafting a hydrophilic polymer, for example, a vinyl type hydrophilic monomer is used. As the vinyl type hydrophilic monomer, acrylic acid, methacrylic acid, hydroxymethyl methacrylic acid, sulfoethyl methacrylic acid, styrene sulfonic acid or alkali metal salts thereof can be used.
　グラフトを行う際には、分離膜に電子線照射、開始剤を用いるケミカルグラフト重合、光開始グラフト重合などを行うことが好ましい。また、重合終了後に、余分なモノマーが除去される。 When grafting is performed, it is preferable to perform electron graft irradiation on the separation membrane, chemical graft polymerization using an initiator, photoinitiated graft polymerization, or the like. In addition, after the polymerization is completed, excess monomer is removed.
　低分子を用いて重合反応させることにより、コーティングを行なう方法としては、グラフトに使用するビニル型の親水性モノマーと、重合開始剤、必要に応じて架橋剤等を用いて、重合反応させる方法、又は、次ぎに述べるような界面重合を用いる方法などが挙げられる。 As a method of coating by carrying out a polymerization reaction using a low molecule, a method of carrying out a polymerization reaction using a vinyl type hydrophilic monomer used for grafting, a polymerization initiator, and a crosslinking agent if necessary, Alternatively, a method using interfacial polymerization as described below can be used.
　界面重合を用いる方法では、例えばポリアミド系のコート層が形成され、一般に、視認できる孔のない均質膜が得られる。ポリアミド系のコート層としては、例えば、多官能アミン成分と多官能酸ハライド成分とを多孔性支持膜上で界面重合させてなるポリアミド系分離機能層がよく知られている。このようなポリアミド系分離機能層はひだ状の微細構造を有することが知られており、この層の厚さは特に限定されるものではないが、０．０５～２μｍ程度であって、好ましくは０．１～１μｍである。この層が薄すぎると膜面欠陥が生じやすくなり、厚すぎると透過性能が悪化することが知られている。 In the method using interfacial polymerization, for example, a polyamide-based coat layer is formed, and generally a homogeneous film having no visible pores can be obtained. As a polyamide-based coating layer, for example, a polyamide-based separation functional layer obtained by interfacial polymerization of a polyfunctional amine component and a polyfunctional acid halide component on a porous support membrane is well known. Such a polyamide-based separation functional layer is known to have a pleated microstructure, and the thickness of this layer is not particularly limited, but is about 0.05 to 2 μm, preferably 0.1 to 1 μm. It is known that if this layer is too thin, film surface defects are likely to occur, and if it is too thick, the transmission performance deteriorates.
　前記ポリアミド系分離機能層を前記ポリマー多孔質層の表面に形成する方法は特に制限されずにあらゆる公知の方法を用いることができる。例えば、界面重合法、相分離法、薄膜塗布法などの方法が挙げられるが、本発明では特に界面重合法が好ましく用いられる。界面重合法は例えば、前記ポリマー多孔質層上を多官能アミン成分含有アミン水溶液で被覆した後、このアミン水溶液被覆面に多官能酸ハライド成分を含有する有機溶液を接触させることで界面重合が生じ、スキン層を形成する方法である。この方法では、アミン水溶液及び有機溶液の塗布後、適宜余剰分を除去して進めることが好ましく、この場合の除去方法としては対象膜を傾斜させて流す方法や、気体を吹き付けて飛ばす方法、ゴム等のブレードを接触させて掻き落とす方法などが好ましく用いられている。 The method for forming the polyamide-based separation functional layer on the surface of the polymer porous layer is not particularly limited, and any known method can be used. Examples of the method include an interfacial polymerization method, a phase separation method, and a thin film coating method. In the present invention, the interfacial polymerization method is particularly preferably used. In the interfacial polymerization method, for example, the polymer porous layer is coated with a polyfunctional amine component-containing amine aqueous solution, and then an organic solution containing a polyfunctional acid halide component is brought into contact with the amine aqueous solution-coated surface to cause interfacial polymerization. This is a method for forming a skin layer. In this method, it is preferable to proceed by removing the surplus as appropriate after the application of the aqueous amine solution and the organic solution. In this case, as a removal method, a method of inclining a target film, a method of blowing off a gas, a rubber, For example, a method of scraping off a blade by contacting the blade is preferably used.
　また、前記工程において、前記アミン水溶液と前記有機溶液が接触するまでの時間は、アミン水溶液の組成、粘度及び多孔性支持膜の表面の孔径にもよるが、１～１２０秒程度であり、好ましくは２～４０秒程度である。前記の間隔が長すぎる場合には、アミン水溶液が多孔性支持膜の内部深くまで浸透・拡散し、未反応多官能アミン成分が多孔性支持膜中に大量に残留し、不具合が生じる場合がある。前記溶液の塗布間隔が短すぎる場合には、余分なアミン水溶液が残存しすぎるため、膜性能が低下する傾向にある。 In the above step, the time required for the aqueous amine solution and the organic solution to contact is approximately 1 to 120 seconds, although it depends on the composition of the aqueous amine solution, the viscosity, and the pore diameter of the surface of the porous support membrane. Is about 2 to 40 seconds. If the interval is too long, the aqueous amine solution may permeate and diffuse deep inside the porous support membrane, and a large amount of unreacted polyfunctional amine component may remain in the porous support membrane, resulting in problems. . When the application interval of the solution is too short, an excessive amine aqueous solution remains, so that the film performance tends to be lowered.
　このアミン水溶液と有機溶液との接触後には、７０℃以上の温度で加熱乾燥してスキン層を形成することが好ましい。これにより膜の機械的強度や耐熱性等を高めることができる。加熱温度は７０～２００℃であることがより好ましく、特に好ましくは８０～１３０℃である。加熱時間は３０秒～１０分程度が好ましく、さらに好ましくは４０秒～７分程度である。 After the contact between the amine aqueous solution and the organic solution, it is preferable to form a skin layer by heating and drying at a temperature of 70 ° C. or higher. Thereby, the mechanical strength and heat resistance of the film can be increased. The heating temperature is more preferably 70 to 200 ° C., particularly preferably 80 to 130 ° C. The heating time is preferably about 30 seconds to 10 minutes, more preferably about 40 seconds to 7 minutes.
　前記アミン水溶液に含まれる多官能アミン成分は、２以上の反応性アミノ基を有する多官能アミンであり、芳香族、脂肪族、及び脂環式の多官能アミンが挙げられる。　前記芳香族多官能アミンとしては、例えば、ｍ－フェニレンジアミン、ｐ－フェニレンジアミン、ｏ－フェニレンジアミン、１，３，５－トリアミノベンゼン、１，２，４－トリアミノベンゼン、３，５－ジアミノ安息香酸、２，４－ジアミノトルエン、２，６－ジアミノトルエン、Ｎ，Ｎ’－ジメチル－ｍ－フェニレンジアミン、２，４－ジアミノアニソール、アミドール、キシリレンジアミン等が挙げられる。前記脂肪族多官能アミンとしては、例えば、エチレンジアミン、プロピレンジアミン、トリス（２－アミノエチル）アミン、ｎ－フェニル－エチレンジアミン等が挙げられる。前記脂環式多官能アミンとしては、例えば、１，３－ジアミノシクロヘキサン、１，２－ジアミノシクロヘキサン、１，４－ジアミノシクロヘキサン、ピペラジン、２，５－ジメチルピペラジン、４－アミノメチルピペラジン等が挙げられる。これらの多官能アミンは１種で用いてもよく、２種以上を併用してもよい。特に本発明では、緻密性の高い分離機能層が得られるｍ－フェニレンジアミンを主成分とすることが好ましい。
前記有機溶液に含まれる多官能酸ハライド成分は、反応性カルボニル基を２個以上有する多官能酸ハライドであり、芳香族、脂肪族、及び脂環式の多官能酸ハライドが挙げられる。前記芳香族多官能酸ハライドとしては、例えば、トリメシン酸トリクロライド、テレフタル酸ジクロライド、イソフタル酸ジクロライド、ビフェニルジカルボン酸ジクロライド、ナフタレンジカルボン酸ジクロライド、ベンゼントリスルホン酸トリクロライド、ベンゼンジスルホン酸ジクロライド、クロロスルホニルベンゼンジカルボン酸ジクロライド等が挙げられる。前記脂肪族多官能酸ハライドとしては、例えば、プロパンジカルボン酸ジクロライド、ブタンジカルボン酸ジクロライド、ペンタンジカルボン酸ジクロライド、プロパントリカルボン酸トリクロライド、ブタントリカルボン酸トリクロライド、ペンタントリカルボン酸トリクロライド、グルタリルハライド、アジポイルハライド等が挙げられる。前記脂環式多官能酸ハライドとしては、例えば、シクロプロパントリカルボン酸トリクロライド、シクロブタンテトラカルボン酸テトラクロライド、シクロペンタントリカルボン酸トリクロライド、シクロペンタンテトラカルボン酸テトラクロライド、シクロヘキサントリカルボン酸トリクロライド、テトラハイドロフランテトラカルボン酸テトラクロライド、シクロペンタンジカルボン酸ジクロライド、シクロブタンジカルボン酸ジクロライド、シクロヘキサンジカルボン酸ジクロライド、テトラハイドロフランジカルボン酸ジクロライド等が挙げられる。これら多官能酸ハライドは１種で用いてもよく、２種以上を併用してもよい。中でも、緻密性の高い分離機能層が得られる芳香族多官能酸ハライドを用いることが好ましい。また、多官能酸ハライド成分の少なくとも一部に３価以上の多官能酸ハライドを用いて、架橋構造を形成することが好ましい。 The polyfunctional amine component contained in the amine aqueous solution is a polyfunctional amine having two or more reactive amino groups, and examples thereof include aromatic, aliphatic, and alicyclic polyfunctional amines. Examples of the aromatic polyfunctional amine include m-phenylenediamine, p-phenylenediamine, o-phenylenediamine, 1,3,5-triaminobenzene, 1,2,4-triaminobenzene, 3,5- Examples thereof include diaminobenzoic acid, 2,4-diaminotoluene, 2,6-diaminotoluene, N, N′-dimethyl-m-phenylenediamine, 2,4-diaminoanisole, amidol, xylylenediamine and the like. Examples of the aliphatic polyfunctional amine include ethylenediamine, propylenediamine, tris (2-aminoethyl) amine, and n-phenyl-ethylenediamine. Examples of the alicyclic polyfunctional amine include 1,3-diaminocyclohexane, 1,2-diaminocyclohexane, 1,4-diaminocyclohexane, piperazine, 2,5-dimethylpiperazine, 4-aminomethylpiperazine and the like. It is done. These polyfunctional amines may be used alone or in combination of two or more. In particular, in the present invention, it is preferable to use m-phenylenediamine as a main component, from which a dense separation functional layer can be obtained.
The polyfunctional acid halide component contained in the organic solution is a polyfunctional acid halide having two or more reactive carbonyl groups, and examples thereof include aromatic, aliphatic, and alicyclic polyfunctional acid halides. Examples of the aromatic polyfunctional acid halide include trimesic acid trichloride, terephthalic acid dichloride, isophthalic acid dichloride, biphenyldicarboxylic acid dichloride, naphthalenedicarboxylic acid dichloride, benzenetrisulfonic acid trichloride, benzenedisulfonic acid dichloride, and chlorosulfonylbenzene. And dicarboxylic acid dichloride. Examples of the aliphatic polyfunctional acid halide include propanedicarboxylic acid dichloride, butanedicarboxylic acid dichloride, pentanedicarboxylic acid dichloride, propanetricarboxylic acid trichloride, butanetricarboxylic acid trichloride, pentanetricarboxylic acid trichloride, glutaryl halide, azide. Poil halide etc. are mentioned. Examples of the alicyclic polyfunctional acid halide include cyclopropane tricarboxylic acid trichloride, cyclobutane tetracarboxylic acid tetrachloride, cyclopentane tricarboxylic acid trichloride, cyclopentane tetracarboxylic acid tetrachloride, cyclohexane tricarboxylic acid trichloride, and tetrahydro Examples include furantetracarboxylic acid tetrachloride, cyclopentanedicarboxylic acid dichloride, cyclobutanedicarboxylic acid dichloride, cyclohexanedicarboxylic acid dichloride, and tetrahydrofurandicarboxylic acid dichloride. These polyfunctional acid halides may be used alone or in combination of two or more. Among them, it is preferable to use an aromatic polyfunctional acid halide that provides a dense separation functional layer. Moreover, it is preferable to form a crosslinked structure using a trifunctional or higher polyfunctional acid halide as at least a part of the polyfunctional acid halide component.
　前記界面重合法において、アミン水溶液中の多官能アミン成分の濃度は特に限定されるものではないが、０．１～７重量％が好ましく、さらに好ましくは１～５重量％である。多官能アミン成分の濃度が低すぎると、スキン層に欠陥が生じやすくなり、塩阻止性能が低下する傾向にある。一方で多官能アミン成分の濃度が高すぎる場合には、厚くなりすぎて透過流束が低下する傾向にある。 In the interfacial polymerization method, the concentration of the polyfunctional amine component in the aqueous amine solution is not particularly limited, but is preferably 0.1 to 7% by weight, more preferably 1 to 5% by weight. If the concentration of the polyfunctional amine component is too low, defects are likely to occur in the skin layer, and the salt blocking performance tends to be reduced. On the other hand, when the concentration of the polyfunctional amine component is too high, it becomes too thick and the permeation flux tends to decrease.
　前記有機溶液中の多官能酸ハライド成分の濃度は特に制限されないが、０．０１～５重量％が好ましく、さらに好ましくは０．０５～３重量％である。多官能酸ハライド成分の濃度が低すぎると、未反応多官能アミン成分が増加するため、スキン層に欠陥が生じやすくなる。一方、多官能酸ハライド成分の濃度が高すぎると、未反応多官能酸ハライド成分が増加するため、スキン層が厚くなりすぎて透過流束が低下する傾向にある。 The concentration of the polyfunctional acid halide component in the organic solution is not particularly limited, but is preferably 0.01 to 5% by weight, more preferably 0.05 to 3% by weight. If the concentration of the polyfunctional acid halide component is too low, the unreacted polyfunctional amine component is increased, and defects are likely to occur in the skin layer. On the other hand, if the concentration of the polyfunctional acid halide component is too high, the amount of unreacted polyfunctional acid halide component increases, so that the skin layer becomes too thick and the permeation flux tends to decrease.
　前記多官能酸ハライドを含有させる有機溶媒としては、水に対する溶解度が低く、多孔性支持膜を劣化させることなく、多官能酸ハライド成分を溶解するものであれば特に限定されず、例えば、シクロヘキサン、ヘプタン、オクタン、及びノナン等の飽和炭化水素、１，１，２－トリクロロトリフルオロエタン等のハロゲン置換炭化水素などを挙げることができる。好ましくは沸点が３００℃以下、さらに好ましくは沸点が２００℃以下の飽和炭化水素である。 The organic solvent containing the polyfunctional acid halide is not particularly limited as long as it has low solubility in water and does not deteriorate the porous support membrane, and can dissolve the polyfunctional acid halide component. For example, cyclohexane, Examples thereof include saturated hydrocarbons such as heptane, octane and nonane, and halogen-substituted hydrocarbons such as 1,1,2-trichlorotrifluoroethane. Preferred is a saturated hydrocarbon having a boiling point of 300 ° C. or lower, more preferably a boiling point of 200 ° C. or lower.
　前記アミン水溶液や有機溶液には、各種性能や取り扱い性の向上を目的とした添加剤を加えてもよい。前記添加剤としては、例えば、ポリビニルアルコール、ポリビニルピロリドン、ポリアクリル酸などのポリマー、ソルビトール、グリセリンなどの多価アルコールや、ドデシルベンゼンスルホン酸ナトリウム、ドデシル硫酸ナトリウム、及びラウリル硫酸ナトリウム等の界面活性剤、重合により生成するハロゲン化水素を除去する水酸化ナトリウム、リン酸三ナトリウム、及びトリエチルアミン等の塩基性化合物、アシル化触媒及び、特開平８－２２４４５２号公報記載の溶解度パラメータが８～１４（ｃａｌ／ｃｍ３）１／２の化合物などが挙げられる。 You may add the additive for the purpose of the improvement of various performance and a handleability to the said amine aqueous solution and organic solution. Examples of the additive include polymers such as polyvinyl alcohol, polyvinyl pyrrolidone and polyacrylic acid, polyhydric alcohols such as sorbitol and glycerin, and surfactants such as sodium dodecylbenzenesulfonate, sodium dodecylsulfate, and sodium laurylsulfate. Basic compounds such as sodium hydroxide, trisodium phosphate and triethylamine for removing hydrogen halide produced by polymerization, acylation catalysts, and solubility parameters described in JP-A-8-224452 are 8 to 14 (cal / Cm 3 ) 1/2 compound and the like.
　前記ポリアミド系分離機能層の露出表面には、各種ポリマー成分からなるコーティング層を更に設けてもよい。前記ポリマー成分は、分離機能層及び多孔性支持膜を溶解せず、また水処理操作時に溶出しないポリマーであれば特に限定されるものではなく、例えば、ポリビニルアルコール、ポリビニルピロリドン、ヒドロキシプロピルセルロース、ポリエチレングリコール、及びケン化ポリエチレン－酢酸ビニル共重合体などが挙げられる。これらのうち、ポリビニルアルコールを用いることが好ましく、特にケン化度が９９％以上のポリビニルアルコールを用いるか、ケン化度９０％以上のポリビニルアルコールを前記スキン層のポリアミド系樹脂と架橋させることで、水処理時に溶出しにくい構成とすることが好ましい。 A coating layer composed of various polymer components may be further provided on the exposed surface of the polyamide-based separation functional layer. The polymer component is not particularly limited as long as it does not dissolve the separation functional layer and the porous support membrane and does not elute during the water treatment operation. For example, polyvinyl alcohol, polyvinyl pyrrolidone, hydroxypropyl cellulose, polyethylene And glycols and saponified polyethylene-vinyl acetate copolymers. Among these, it is preferable to use polyvinyl alcohol, in particular, by using polyvinyl alcohol having a saponification degree of 99% or more, or by crosslinking polyvinyl alcohol having a saponification degree of 90% or more with the polyamide-based resin of the skin layer, It is preferable to use a structure that does not easily dissolve during water treatment.
　本発明では、親水性ポリマーの分離膜又は親水化処理後の分離膜の少なくとも一方の表面が、平均孔径１，０００ｎｍ以下の多孔質構造、又は非多孔質構造であり、透過流量を高めて濃縮の処理効率を高める観点から、平均孔径１～５００ｎｍの多孔質構造であることが好ましい。 In the present invention, at least one surface of the separation membrane of the hydrophilic polymer or the separation membrane after the hydrophilization treatment has a porous structure or non-porous structure having an average pore diameter of 1,000 nm or less, and is concentrated by increasing the permeation flow rate. From the viewpoint of improving the treatment efficiency, a porous structure having an average pore diameter of 1 to 500 nm is preferable.
　（膜エレメント）
　本発明における膜エレメントは、以上のような気泡液濃縮用分離膜を備えている。このような膜エレメントの形態としては、特に限定されるものではなく、フレームアンドプレート型などの平膜型、スパイラル型、プリーツ型などが挙げられる。また、気泡液濃縮用分離膜が中空糸膜である場合は、複数の中空糸膜を束ねて、一方又は両方の端部を樹脂等で封止した中空糸膜エレメントが使用される。これらの膜エレメントのうち、一般に圧力と流れ効率の関係よりスパイラル型膜エレメントが好ましい。 (Membrane element)
The membrane element in the present invention includes the separation membrane for concentrating bubble liquid as described above. The form of such a membrane element is not particularly limited, and examples thereof include a flat membrane type such as a frame and plate type, a spiral type, and a pleated type. Moreover, when the separation membrane for concentrating bubble liquid is a hollow fiber membrane, a hollow fiber membrane element in which a plurality of hollow fiber membranes are bundled and one or both ends are sealed with a resin or the like is used. Of these membrane elements, spiral membrane elements are generally preferred from the relationship between pressure and flow efficiency.
　スパイラル型の膜エレメントは、例えば図２に示すように、分離膜２、供給側流路材６及び透過側流路材３を含む積層体と、その積層体を巻回した有孔の中心管５と、供給側流路と透過側流路との混合を防止する封止部２１とを備えている。本実施形態では、分離膜２、供給側流路材６及び透過側流路材３を含む複数の分離膜ユニットが、中心管５の回りに巻きつけられた巻回体Ｒである場合の例を示す。 For example, as shown in FIG. 2, the spiral membrane element includes a laminated body including a separation membrane 2, a supply-side flow path member 6, and a permeate-side flow path member 3, and a perforated central tube around which the laminated body is wound. 5 and a sealing portion 21 that prevents mixing of the supply-side flow path and the permeation-side flow path. In the present embodiment, an example in which a plurality of separation membrane units including the separation membrane 2, the supply-side flow path material 6 and the permeation-side flow path material 3 are wound bodies R wound around the central tube 5. Indicates.
　供給側流路と透過側流路との混合を防止するための封止部２１は、例えば、透過側流路材３の両面に分離膜２を重ね合わせて３辺を接着することにより封筒状膜４（袋状膜）を形成する場合、外周側端辺の封止部２１と上流側端辺及び下流側端辺とに封止部２１が形成される。また、上流側端辺及び下流側端辺の内周側端部と中心管５との間にも封止部２１を設けるのが好ましい。 The sealing part 21 for preventing the mixing of the supply side flow path and the permeation side flow path is, for example, an envelope shape by overlapping the separation membrane 2 on both surfaces of the permeation side flow path material 3 and bonding the three sides. When the film 4 (bag-like film) is formed, the sealing portion 21 is formed on the sealing portion 21 on the outer peripheral side edge, the upstream side edge, and the downstream side edge. Moreover, it is preferable to provide the sealing part 21 also between the inner peripheral side edge part of the upstream side edge and the downstream side edge and the central tube 5.
　封筒状膜４は、その開口部を中心管５に取り付け、ネット状（網状）の供給側流路材６とともに中心管５の外周面にスパイラル状に巻回することにより、巻回体Ｒが形成される。この巻回体Ｒの上流側には、例えば、シールキャリア等の上流側端部材１０が設けられ、下流側には、必要に応じてテレスコープ防止材等の下流側端部材２０が設けられる。 The envelope film 4 is attached to the central tube 5 at its opening, and is wound spirally around the outer peripheral surface of the central tube 5 together with the net-like (net-like) supply-side flow path member 6 so that the wound body R becomes It is formed. An upstream end member 10 such as a seal carrier is provided on the upstream side of the wound body R, and a downstream end member 20 such as a telescope prevention member is provided on the downstream side as necessary.
　このようなスパイラル型の膜エレメントにおいては、通常、封筒状膜４は２０～４０組の封筒状膜４を巻回することが可能となる。 In such a spiral membrane element, normally, 20 to 40 sets of envelope membrane 4 can be wound around the envelope membrane 4.
　上記膜エレメント１を使用する際は、供給液７（濃縮前の原液）は膜エレメント１の一方の端面側から供給される。供給された供給液７は、供給側流路材６に沿って中心管５の軸芯方向Ａ１に平行な方向に流れ、膜エレメント１の他方の端面側から気泡を含んだ濃縮液９として排出される。また、供給液７が供給側流路材６に沿って流れる過程で分離膜２を透過した透過液８は、図中破線矢印に示すように透過側流路材３に沿って開孔５ａから中心管５の内部に流れ込み、この中心管５の端部から排出される。つまり、この膜エレメント１は、分離膜２の一方の膜面に沿って供給液が流動しながら、透過液を分離膜２の他方の膜面側に透過させる構造である。 When the membrane element 1 is used, the supply liquid 7 (stock solution before concentration) is supplied from one end face side of the membrane element 1. The supplied supply liquid 7 flows in a direction parallel to the axial direction A1 of the center tube 5 along the supply-side flow path member 6, and is discharged as a concentrated liquid 9 containing bubbles from the other end face side of the membrane element 1. Is done. Further, the permeated liquid 8 that has permeated the separation membrane 2 in the course of the supply liquid 7 flowing along the supply-side flow path material 6 passes through the aperture 5a along the permeation-side flow path material 3 as shown by the broken line arrows in the figure. It flows into the center tube 5 and is discharged from the end of the center tube 5. That is, the membrane element 1 has a structure in which the permeated liquid permeates the other membrane surface side of the separation membrane 2 while the supply liquid flows along one membrane surface of the separation membrane 2.
　なお、流路材は一般に、膜面に流体を満遍なく供給するための間隙を確保する役割を有する。このような流路材は、例えばネット、編み物、凹凸加工シートなどを用いることができ、最大厚さが０．１～３ｍｍ程度のものを適宜必要に応じて用いることができる。このような流路材では、圧力損失が低い方が好ましく、さらに適度な乱流効果を生じさせるものが好ましい。また、流路材は分離膜の両面に設置するが、供給液側には供給側流路材、透過液側には透過側流路材として、異なる流路材を用いることが一般的である。供給側流路材では目が粗く厚いネット状の流路材を用いる一方で、透過側流路材では目の細かい織物や編物の流路材を用いる。 Note that the channel material generally has a role of ensuring a gap for uniformly supplying fluid to the membrane surface. As such a channel material, for example, a net, a knitted fabric, a concavo-convex processed sheet or the like can be used, and a material having a maximum thickness of about 0.1 to 3 mm can be used as needed. In such a channel material, it is preferable that the pressure loss is low, and further, a material that causes an appropriate turbulent flow effect is preferable. In addition, the channel material is installed on both sides of the separation membrane, but it is common to use different channel materials as the supply side channel material on the supply liquid side and the permeate side channel material on the permeate side. . The supply-side channel material uses a coarse and thick net-like channel material, while the permeate-side channel material uses a fine woven or knitted channel material.
　前記供給側流路材は、例えば前記の二つ折りにした分離膜の内面側に設けられる。供給側流路材の構造は、一般に線状物を格子状に配列した網目構造のものを好ましく利用することができる。構成する材料としては特に限定されるものではないが、ポリエチレンやポリプロピレンなどが用いられる。この供給側流路材の厚さは、一般に０．２～２．０ｍｍであり、０．５～１．０ｍｍが好ましい。 The supply channel material is provided on the inner surface side of the two-folded separation membrane, for example. As the structure of the supply-side channel material, a network structure in which linear objects are generally arranged in a lattice can be preferably used. Although it does not specifically limit as a material to comprise, Polyethylene, a polypropylene, etc. are used. The thickness of the supply side channel material is generally 0.2 to 2.0 mm, preferably 0.5 to 1.0 mm.
　前記透過側流路材は、例えば前記の二つ折りにした分離膜の外面側に設けられる。この透過側流路材には膜にかかる圧力を膜背面から支えるとともに、透過液の流路を確保することが求められる。一般にはポリエチレンやポリプロピレンから構成されるネットやトリコット編物が用いられる。特にポリエチレンテレフタレートからなるトリコット編物が特に好ましく用いられる。 The permeate-side channel material is provided on the outer surface side of the two-folded separation membrane, for example. This permeation side channel material is required to support the pressure applied to the membrane from the back side of the membrane and secure a permeate channel. In general, a net or tricot knitted fabric made of polyethylene or polypropylene is used. In particular, a tricot knitted fabric made of polyethylene terephthalate is particularly preferably used.
　前記中心管としては、パイプ（中空管）の壁面に複数の小孔を有する有孔中空管であれば特に限定されるものではない。気泡液濃縮の際には、分離膜を経た透過液が壁面の孔から中空管中に侵入し、透過側流路を形成する。中心管の長さはエレメントの軸方向長さより長いものが一般的だが、複数に分割するなど連結構造の中心管を用いてもよい。中心管を構成する材料としては特に限定されるものではないが、熱硬化性樹脂または熱可塑性樹脂が用いられる。 The center tube is not particularly limited as long as it is a perforated hollow tube having a plurality of small holes on the wall surface of the pipe (hollow tube). At the time of bubbling liquid concentration, the permeated liquid that has passed through the separation membrane enters the hollow tube through the hole in the wall surface, and forms a permeate-side flow path. The length of the central tube is generally longer than the length of the element in the axial direction, but a central tube having a connection structure such as a plurality of divisions may be used. Although it does not specifically limit as a material which comprises a center pipe | tube, A thermosetting resin or a thermoplastic resin is used.
　（膜モジュール）
　本発明における膜モジュールは、前述のような気泡液濃縮用分離膜を備える膜エレメントと、その膜エレメントを収容して濃縮側流路と透過側流路とを形成する容器と、を備えるものである。 (Membrane module)
The membrane module according to the present invention includes a membrane element including the separation membrane for concentrating bubble liquid as described above, and a container that accommodates the membrane element and forms a concentration side channel and a permeation side channel. is there.
　本実施の形態で示す膜モジュール３０は、例えば、図３に示すように、スパイラル型の膜エレメント１と、これを収容し、供給液７を供給する供給部３２、濃縮液９を排出する濃縮液排出部３３、および透過液８を排出する透過液排出部３４を有する容器３１と、を備える。 The membrane module 30 shown in the present embodiment includes, for example, a spiral membrane element 1, a supply unit 32 that supplies the supply element 7, and a concentration unit 9 that discharges the concentrate 9, as shown in FIG. 3. A container 31 having a liquid discharge part 33 and a permeate discharge part 34 for discharging the permeate 8.
　図示した例では、上流側端部材１０がシール材１１を保持し、シール材１１が容器３１の内壁に圧接することで、供給液７を膜エレメント１の巻回体Ｒの内部に導く構造になっている。巻回体Ｒの内部から流出した濃縮液９は、容器３１の内部空間を経て濃縮液排出部３３と流動する。また、中心管５の一端（図３で左端）が閉塞され、他端（図３で右端）が容器３１の透過液排出部３４に連結されている。膜エレメント１が容器３１内に複数収容される場合は、隣接する膜エレメント１の中心管５同士が、連結部材（図示省略）等を介して連結される。このような構造により、容器３１は、濃縮側流路と透過側流路とを形成している。 In the illustrated example, the upstream end member 10 holds the sealing material 11, and the sealing material 11 is in pressure contact with the inner wall of the container 31, thereby leading the supply liquid 7 to the inside of the wound body R of the membrane element 1. It has become. The concentrated liquid 9 that has flowed out from the inside of the wound body R flows with the concentrated liquid discharger 33 through the internal space of the container 31. Further, one end (the left end in FIG. 3) of the central tube 5 is closed, and the other end (the right end in FIG. 3) is connected to the permeate discharge part 34 of the container 31. When a plurality of membrane elements 1 are accommodated in the container 31, the central tubes 5 of the adjacent membrane elements 1 are connected to each other via a connecting member (not shown) or the like. With such a structure, the container 31 forms a concentration side channel and a permeation side channel.
　本発明では、濃縮側流路が加圧された状態で、直径１μｍ未満の気泡を含有する液体を、供給液７として供給部３２から供給することで、気泡液濃縮用分離膜により気泡液が濃縮された濃縮液９を濃縮液排出部３３から排出することができる。また、気泡液濃縮用分離膜を透過した透過液８を透過液排出部３４から排出することができる。 In the present invention, a liquid containing bubbles having a diameter of less than 1 μm is supplied from the supply unit 32 as the supply liquid 7 in a state where the concentration side flow path is pressurized, so that the bubble liquid is separated from the bubble liquid concentration separation membrane. The concentrated concentrate 9 can be discharged from the concentrated liquid discharge portion 33. Further, the permeated liquid 8 that has permeated through the bubble liquid concentrating separation membrane can be discharged from the permeated liquid discharging section 34.
　なお、排出される透過液８には気泡が含まれていない（ほぼ液体のみが分離されている）ことがより好ましいが、分離膜の性質、透過流量、濃縮の処理効率などにより透過液８にも少量の気泡が含まれていてもよい。 It is more preferable that the discharged permeate 8 does not contain bubbles (substantially only the liquid is separated). However, the permeate 8 is not suitable for the properties of the separation membrane, permeate flow rate, processing efficiency of concentration, etc. May contain a small amount of bubbles.
　（気泡液濃縮装置）
　本発明の気泡液濃縮装置は、例えば図５に示すように、供給液中に存在する気泡を分離膜２により濃縮するものであり、膜モジュール３０の供給側流路（濃縮側流路）が加圧された状態で、気泡液の濃縮が行われる。 (Bubble liquid concentrator)
As shown in FIG. 5, for example, the bubble liquid concentrating device of the present invention concentrates bubbles existing in the supply liquid by the separation membrane 2, and the supply side flow path (concentration side flow path) of the membrane module 30 is provided. The bubble liquid is concentrated in a pressurized state.
　濃縮側流路が加圧された状態とするため、例えば図５に示すように、供給液槽３５から供給液７をポンプ３７で容器３１に加圧供給する際に、供給液７の一部を配管４２で循環させつつ、濃縮液９を弁３９を介して配管４１により循環させながら、弁３９により流量を調整することで、濃縮側流路の圧力を調整することができる。その際、圧力計３８と流量計４０により、各々、圧力と流量を測定することができる。透過液８は、透過液槽４３に排出される。 In order to make the concentration side flow path pressurized, a part of the supply liquid 7 is supplied when the supply liquid 7 is pressurized and supplied from the supply liquid tank 35 to the container 31 by the pump 37, as shown in FIG. The pressure of the concentration side flow path can be adjusted by adjusting the flow rate with the valve 39 while circulating the concentrated liquid 9 through the pipe 41 and circulating the concentrated liquid 9 through the pipe 42. At that time, the pressure and flow rate can be measured by the pressure gauge 38 and the flow meter 40, respectively. The permeate 8 is discharged to the permeate tank 43.
　配管４２には、圧力調整を容易にするために、流量を調整する弁を設けることが好ましい。 The piping 42 is preferably provided with a valve for adjusting the flow rate in order to facilitate pressure adjustment.
　本発明の気泡液濃縮装置により、気泡液の濃縮を行う場合、濃縮側流路の圧力は、分離膜の透過流束に応じて決定されるが、例えば０．０５～６ＭＰａが挙げられる。また、膜面における供給液の平均線速度は、気泡が消失するのを抑制する観点から、０．１～１００ｃｍ／秒が好ましく、１～５０ｃｍ／秒がより好ましい。さらに好ましくは５～３０ｃｍ／秒である。供給液の平均線速度が低すぎると気泡消失抑制効果が不十分となり、高すぎると流路の圧損増大、エネルギーの消費が大きくなり好ましくない。 When the bubble liquid is concentrated by the bubble liquid concentration apparatus of the present invention, the pressure in the concentration side flow path is determined according to the permeation flux of the separation membrane, and may be 0.05 to 6 MPa, for example. Further, the average linear velocity of the supply liquid on the film surface is preferably 0.1 to 100 cm / second, more preferably 1 to 50 cm / second, from the viewpoint of suppressing the disappearance of bubbles. More preferably, it is 5 to 30 cm / sec. If the average linear velocity of the supply liquid is too low, the effect of suppressing the disappearance of bubbles is insufficient, and if it is too high, the pressure loss of the flow path increases and energy consumption increases, which is not preferable.
　（気泡液濃縮装置の他の実施形態）
　　（１）前述の実施形態では、平膜を有するスパイラル型の膜エレメントを用いる気泡液濃縮装置の例を示したが、本発明では、中空糸膜を有する膜エレメントやこれを用いた膜モジュールを構成することも可能である。 (Another embodiment of the bubble liquid concentrating device)
(1) In the above-described embodiment, an example of a bubble liquid concentrating device using a spiral membrane element having a flat membrane has been shown. However, in the present invention, a membrane element having a hollow fiber membrane and a membrane module using the same are provided. It is also possible to configure.
　例えば、図４に示すように、分離膜２である複数の中空糸膜を束ねて、一方の端部（図４で左端）を樹脂等の閉塞部材１５で閉塞するように封止し、他方の端部（図４で右端）を樹脂等の封止部材１６で開口するように封止した中空糸膜エレメントが使用できる。封止部材１６の外周と、容器３１との内面には、シール材１７が介在する。これにより、濃縮側流路が形成され、供給液７を供給部３２から供給することで、気泡液濃縮用分離膜により気泡液が濃縮された濃縮液９を濃縮液排出部３３から排出することができる。また、気泡液濃縮用分離膜を透過した透過液８を透過液排出部３４から排出することができる。 For example, as shown in FIG. 4, a plurality of hollow fiber membranes that are separation membranes 2 are bundled and sealed so that one end (the left end in FIG. 4) is closed with a closing member 15 such as resin, A hollow fiber membrane element whose end (right end in FIG. 4) is sealed with a sealing member 16 such as resin can be used. A sealing material 17 is interposed between the outer periphery of the sealing member 16 and the inner surface of the container 31. As a result, a concentration side flow path is formed, and the supply liquid 7 is supplied from the supply part 32, whereby the concentrate 9 in which the bubble liquid is concentrated by the separation liquid for bubble liquid concentration is discharged from the concentrate discharge part 33. Can do. Further, the permeated liquid 8 that has permeated through the bubble liquid concentrating separation membrane can be discharged from the permeated liquid discharging section 34.
　図示した例では、一方の端部（図４で左端）を樹脂等の閉塞部材１５で閉塞するように封止しているが、複数の中空糸膜をＵ字型に配置して、両方の端部を樹脂等の封止部材１６で開口するように封止した中空糸膜エレメントとすることも可能である。 In the illustrated example, one end (left end in FIG. 4) is sealed so as to be closed with a closing member 15 such as a resin, but a plurality of hollow fiber membranes are arranged in a U-shape, It is also possible to provide a hollow fiber membrane element whose end is sealed so as to be opened by a sealing member 16 such as a resin.
　また、中空糸膜の両側の端部を樹脂等の封止部材１６で開口するように封止した中空糸膜エレメントとすることも可能であり、その場合、両側の封止部材１６の外周と、容器３１との内面に、シール材１７を介在させることで、容器３１内に、濃縮側流路と透過側流路とを形成することができる。このような構造の膜モジュールでは、中空糸膜の外部だけでなく、内部にも気泡液濃縮のための液体を供給することが可能である。 Further, it is possible to provide a hollow fiber membrane element in which the end portions on both sides of the hollow fiber membrane are sealed so as to be opened with a sealing member 16 such as a resin. The concentration side flow path and the permeation side flow path can be formed in the container 31 by interposing the sealing material 17 on the inner surface of the container 31. In the membrane module having such a structure, it is possible to supply a liquid for concentrating bubble liquid not only to the outside of the hollow fiber membrane but also to the inside thereof.
　（２）前述の実施形態では、液体を循環させながら気泡液の濃縮を行う方式の気泡液濃縮装置の例を示したが、本発明の気泡液濃縮装置は、１パスで気泡液の濃縮を行う方式であってもよい。 (2) In the above-described embodiment, the example of the bubble liquid concentrating device that concentrates the bubble liquid while circulating the liquid is shown. However, the bubble liquid concentrating apparatus of the present invention can concentrate the bubble liquid in one pass. The method of performing may be used.
　例えば、図６に示すように、供給液槽３５から供給液７をポンプ３７で容器３１に加圧供給する際に、濃縮液９を弁３９を介して配管４１により排出しながら、弁３９により流量を調整することで、濃縮側流路の圧力を調整することができる。これにより気泡液を濃縮しつつ、透過液８を排出することができる。 For example, as shown in FIG. 6, when supplying the supply liquid 7 from the supply liquid tank 35 to the container 31 with the pump 37, the concentrated liquid 9 is discharged by the pipe 41 through the valve 39, By adjusting the flow rate, the pressure in the concentration side channel can be adjusted. Thereby, the permeate 8 can be discharged while concentrating the bubble liquid.
　（３）前述の実施形態では、気泡を有する供給液を供給液槽に溜めてから膜モジュールに供給する気泡液濃縮装置の例を示したが、直径１μｍ未満の気泡を有する液体を生成する装置から、直接、膜モジュールに液体を供給することも可能である。 (3) In the above-described embodiment, an example of a bubble liquid concentrating device that supplies a supply liquid having bubbles in a supply liquid tank and then supplies the supply liquid to the membrane module has been described, but an apparatus that generates a liquid having bubbles having a diameter of less than 1 μm It is also possible to supply the liquid directly to the membrane module.
　（高密度微細気泡液生成装置）
　本発明の高密度微細気泡液生成装置は、例えば図７に示すように、以上のような本発明の気泡液濃縮装置と、その気泡液濃縮装置に直径１μｍ未満の気泡を含む供給液を供給する気泡生成装置５０と、を備えることを特徴とする。本発明では、気泡生成装置５０から直接、気泡液濃縮装置に供給液を供給してもよく、供給液槽に溜めてから供給してもよい。気泡生成装置５０としては、例えば、特開２０１４－１５５９２０号公報に詳述されているようなものを採用することが可能である。 (High-density fine bubble liquid generator)
For example, as shown in FIG. 7, the high-density fine bubble liquid generation apparatus of the present invention supplies the above-described bubble liquid concentration apparatus of the present invention and the supply liquid containing bubbles having a diameter of less than 1 μm to the bubble liquid concentration apparatus. And a bubble generating device 50 that performs the above-described operation. In the present invention, the supply liquid may be supplied directly from the bubble generating device 50 to the bubble liquid concentrating device, or may be supplied after being stored in the supply liquid tank. As the bubble generation device 50, for example, the one described in detail in Japanese Patent Application Laid-Open No. 2014-155920 can be adopted.
　図８には、気泡生成装置５０の一例の縦断面図を示している。気泡生成装置５０は、気体と液体とを混合して、当該気体の微細気泡を含む液体を生成する。本実施の形態では、混合前の対象液５１として水が使用される。水と混合される気体として、空気が使用される。気泡生成装置５０は、微細気泡生成ノズル５２と、加圧液生成部５３と、送出配管５４ａと、補助配管５４ｂと、戻し配管５４ｃと、ポンプ５４ｄと、液貯留部５５とを備える。液貯留部５５には対象液５１が貯留される。気泡生成装置５０を稼動することにより、対象液５１が供給液となる。 FIG. 8 shows a longitudinal sectional view of an example of the bubble generating device 50. The bubble generating device 50 mixes a gas and a liquid, and generates a liquid containing fine bubbles of the gas. In the present embodiment, water is used as the target liquid 51 before mixing. Air is used as the gas mixed with water. The bubble generation device 50 includes a fine bubble generation nozzle 52, a pressurized liquid generation unit 53, a delivery pipe 54a, an auxiliary pipe 54b, a return pipe 54c, a pump 54d, and a liquid storage unit 55. The target liquid 51 is stored in the liquid storage unit 55. By operating the bubble generating device 50, the target liquid 51 becomes the supply liquid.
　送出配管５４ａは、加圧液生成部５３と微細気泡生成ノズル５２とを接続する。加圧液生成部５３は、気体を加圧溶解させた加圧液５６を生成し、送出配管５４ａを介して微細気泡生成ノズル５２に供給する。微細気泡生成ノズル５２の噴出口は、液貯留部５５内に位置し、送出配管５４ａは、実質的に加圧液生成部５３と液貯留部５５とを接続する。 The delivery pipe 54 a connects the pressurized liquid generation unit 53 and the fine bubble generation nozzle 52. The pressurizing liquid generating unit 53 generates a pressurizing liquid 56 in which gas is dissolved under pressure, and supplies the pressurized liquid 56 to the fine bubble generating nozzle 52 through the delivery pipe 54a. The outlet of the fine bubble generating nozzle 52 is located in the liquid storage unit 55, and the delivery pipe 54 a substantially connects the pressurized liquid generation unit 53 and the liquid storage unit 55.
　微細気泡生成ノズル５２から加圧液５６を対象液５１中に噴出することにより、対象液５１中に微細気泡が生成する。本実施の形態では、空気の微細気泡が対象液５１中に生成する。 The fine bubbles are generated in the target liquid 51 by ejecting the pressurized liquid 56 into the target liquid 51 from the fine bubble generating nozzle 52. In the present embodiment, fine air bubbles are generated in the target liquid 51.
　補助配管５４ｂは、送出配管５４ａと同様に、加圧液生成部５３と液貯留部５５とを接続する。補助配管５４ｂは、加圧液生成部５３にて余剰の気体を分離する際に余剰の気体と共に排出される液体を液貯留部５５へと導く。戻し配管５４ｃにはポンプ５４ｄが設けられ、ポンプ５４ｄにより、戻し配管５４ｃを経由して、対象液５１が液貯留部５５から加圧液生成部５３へと戻される。 The auxiliary pipe 54b connects the pressurized liquid generator 53 and the liquid reservoir 55 in the same manner as the delivery pipe 54a. The auxiliary pipe 54 b guides the liquid discharged together with the excess gas to the liquid storage unit 55 when the excess gas is separated by the pressurized liquid generation unit 53. The return pipe 54c is provided with a pump 54d, and the target liquid 51 is returned from the liquid reservoir 55 to the pressurized liquid generator 53 via the return pipe 54c by the pump 54d.
　加圧液生成部５３は、混合ノズル５７と、加圧液生成容器５８とを備える。混合ノズル５７の気体流入口からは、レギュレータや流量計等を介して空気が流入する。混合ノズル５７では、ポンプ５４ｄにより圧送された液体と、空気とが、混合ノズル５７により混合され、加圧液生成容器５８内に向けて噴出される。 The pressurized liquid generating unit 53 includes a mixing nozzle 57 and a pressurized liquid generating container 58. From the gas inlet of the mixing nozzle 57, air flows in through a regulator, a flow meter or the like. In the mixing nozzle 57, the liquid pumped by the pump 54 d and the air are mixed by the mixing nozzle 57 and ejected into the pressurized liquid generating container 58.
　加圧液生成容器５８内は、後述する微細気泡生成ノズル５２の形状と微細気泡生成ノズル５２を加圧液５６が通過することにより加圧されて、大気圧よりも圧力が高い状態（以下、「加圧環境」という。）となっている。混合ノズル５７から噴出された液体と気体とが混合された流体（以下、「混合流体５９」という。）は、加圧液生成容器５８内を加圧環境下にて流れる間に、気体が液体に加圧溶解した加圧液５６となる。 The pressurized liquid generating container 58 is pressurized by passing the pressurized liquid 56 through the shape of the fine bubble generating nozzle 52 and the fine bubble generating nozzle 52 described later (hereinafter referred to as “pressure”). "Pressurized environment"). The fluid (hereinafter referred to as “mixed fluid 59”) in which the liquid and the gas ejected from the mixing nozzle 57 are mixed is flowed through the pressurized liquid generating container 58 in a pressurized environment. It becomes the pressurizing liquid 56 which melt | dissolved under pressure.
　混合ノズル５７は、上述のポンプ５４ｄにより圧送された液体が流入する液体流入口と、気体が流入する気体流入口と、混合流体５９を噴出する混合流体噴出口とを備える。混合流体５９は、液体流入口から流入した液体および気体流入口から流入した気体が混合されることにより生成される。液体流入口、気体流入口および混合流体噴出口はそれぞれ略円形である。液体流入口から混合流体噴出口に向かうノズル流路の流路断面、および、気体流入口からノズル流路に向かう気体流路の流路断面も略円形である。流路断面とは、ノズル流路や気体流路等の流路の中心軸に垂直な断面、すなわち、流路を流れる流体の流れに垂直な断面を意味する。また、以下の説明では、流路断面の面積を「流路面積」という。ノズル流路は、流路面積が流路の中間部で小さくなるベンチュリ管状である。 The mixing nozzle 57 includes a liquid inlet through which the liquid pumped by the pump 54d described above flows, a gas inlet through which gas flows, and a mixed fluid outlet through which the mixed fluid 59 is ejected. The mixed fluid 59 is generated by mixing the liquid flowing in from the liquid inlet and the gas flowing in from the gas inlet. Each of the liquid inlet, the gas inlet, and the mixed fluid outlet is substantially circular. The cross section of the nozzle flow path from the liquid inlet to the mixed fluid outlet and the cross section of the gas flow path from the gas inlet to the nozzle flow path are also substantially circular. The channel cross section means a cross section perpendicular to the central axis of a flow channel such as a nozzle flow channel or a gas flow channel, that is, a cross section perpendicular to the flow of fluid flowing through the flow channel. In the following description, the area of the channel cross section is referred to as “channel area”. The nozzle channel is a Venturi tube whose channel area becomes smaller at the middle of the channel.
　混合ノズル５７は、液体流入口から混合流体噴出口に向かって順に連続して配置される導入部と、第１テーパ部と、喉部と、気体混合部と、第２テーパ部と、導出部とを備える。混合ノズル５７は、また、内部に気体流路が設けられた気体供給部を備える。 The mixing nozzle 57 includes an introduction portion, a first taper portion, a throat portion, a gas mixing portion, a second taper portion, and a lead-out portion that are continuously arranged in order from the liquid inlet to the mixed fluid outlet. With. The mixing nozzle 57 also includes a gas supply unit provided with a gas flow path therein.
　混合ノズル５７では、液体流入口からノズル流路に流入した液体が、喉部で加速されて静圧が低下し、喉部および気体混合部において、ノズル流路内の圧力が大気圧よりも低くなる。これにより、気体流入口から気体が吸引され、気体流路を通過して気体混合部に流入し、液体と混合されて混合流体５９が生成される。混合流体５９は、第２テーパ部および導出部において減速されて静圧が増大し、混合流体噴出口を介して加圧液生成容器５８内に噴出される。 In the mixing nozzle 57, the liquid flowing into the nozzle channel from the liquid inlet is accelerated in the throat and the static pressure is reduced. In the throat and the gas mixing unit, the pressure in the nozzle channel is lower than the atmospheric pressure. Become. Thereby, gas is attracted | sucked from a gas inflow port, passes a gas flow path, flows in into a gas mixing part, is mixed with a liquid, and the mixed fluid 59 is produced | generated. The mixed fluid 59 is decelerated at the second tapered portion and the outlet portion to increase the static pressure, and is ejected into the pressurized liquid generating container 58 through the mixed fluid ejection port.
　図８に示すように、加圧液生成容器５８は、上下方向に積層される第１流路５８ａと、第２流路５８ｂと、第３流路５８ｃと、第４流路５８ｄと、第５流路５８ｅとを備える。流路５８ａ～５８ｅは、水平方向に延びる管路であり、流路５８ａ～５８ｅの長手方向に垂直な断面は略矩形である。本実施の形態では、流路５８ａ～５８ｅの幅は、約４０ｍｍである。 As shown in FIG. 8, the pressurized liquid generating container 58 includes a first channel 58a, a second channel 58b, a third channel 58c, a fourth channel 58d, 5 flow paths 58e. The flow paths 58a to 58e are pipe lines extending in the horizontal direction, and the cross section perpendicular to the longitudinal direction of the flow paths 58a to 58e is substantially rectangular. In the present embodiment, the width of the flow paths 58a to 58e is about 40 mm.
　第１流路５８ａの上流側の端部（すなわち、図８中の左側の端部）には、混合ノズル５７が取り付けられており、混合ノズル５７から噴出された後の混合流体５９は、加圧環境下にて図８中の右側に向かって流れる。本実施の形態では、第１流路５８ａ内の混合流体５９の液面より上方にて混合ノズル５７から混合流体５９が噴出され、噴出された直後の混合流体５９は、第１流路５８ａの下流側の壁面（すなわち、図８中の右側の壁面）に衝突する前に上記液面に直接衝突する。混合ノズル５７から噴出された混合流体５９を液面に直接衝突させるためには、第１流路５８ａの長さを、混合ノズル５７の混合流体噴出口５７ｂの中心と第１流路５８ａの下面との間の上下方向の距離の７．５倍よりも大きくすることが好ましい。 A mixing nozzle 57 is attached to the upstream end portion of the first flow path 58a (that is, the left end portion in FIG. 8), and the mixed fluid 59 ejected from the mixing nozzle 57 is added It flows toward the right side in FIG. 8 under a pressure environment. In the present embodiment, the mixed fluid 59 is ejected from the mixing nozzle 57 above the liquid level of the mixed fluid 59 in the first flow path 58a, and the mixed fluid 59 immediately after the ejection is discharged from the first flow path 58a. It directly collides with the liquid surface before colliding with the downstream wall surface (that is, the right wall surface in FIG. 8). In order to cause the mixed fluid 59 ejected from the mixing nozzle 57 to directly collide with the liquid surface, the length of the first flow path 58a is set so that the center of the mixed fluid outlet 57b of the mixing nozzle 57 and the lower surface of the first flow path 58a. It is preferable to make it larger than 7.5 times the vertical distance between the two.
　加圧液生成部５３では、混合ノズル５７の混合流体噴出口５７ｂの一部または全体が、第１流路５８ａ内の混合流体５９の液面よりも下側に位置してもよい。これにより、上述と同様に、第１流路５８ａ内において、混合ノズル５７から噴出された直後の混合流体５９が、第１流路５８ａ内を流れる混合流体５９に直接衝突する。 In the pressurized liquid generating unit 53, a part or the whole of the mixed fluid ejection port 57b of the mixing nozzle 57 may be located below the liquid level of the mixed fluid 59 in the first flow path 58a. As a result, in the same manner as described above, the mixed fluid 59 immediately after being ejected from the mixing nozzle 57 directly collides with the mixed fluid 59 flowing in the first channel 58a in the first channel 58a.
　第１流路５８ａの下流側の端部の下面には、略円形の開口５８ｏが設けられており、第１流路５８ａを流れる混合流体５９は、下方に位置する第２流路５８ｂへと開口５８ｏを介して落下する。このようにして、第１流路５８ａ、第２流路５８ｂ、第３流路５８ｃ、第４流路５８ｄへと落下する。第１流路５８ａ～第４流路５８ｄでは、混合流体５９は、気泡を含む液体の層と、その上方に位置する気体の層に分かれている。 A substantially circular opening 58o is provided on the lower surface of the downstream end portion of the first flow path 58a, and the mixed fluid 59 flowing through the first flow path 58a is directed to the second flow path 58b positioned below. It falls through the opening 58o. In this way, it falls to the first flow path 58a, the second flow path 58b, the third flow path 58c, and the fourth flow path 58d. In the first flow path 58a to the fourth flow path 58d, the mixed fluid 59 is divided into a liquid layer containing bubbles and a gas layer located thereabove.
　第４流路５８ｄでは、下流側の端部の下面に設けられた略円形の開口５８ｏを介して、下方に位置する第５流路５８ｅへと流入（すなわち、落下）する。第５流路５８ｅでは、第１流路５８ａ～第４流路５８ｄとは異なり、気体の層は存在しておらず、第５流路５８ｅ内に充満する液体内において、第５流路５８ｅの上面近傍に気泡が僅かに存在する状態となっている。 In the fourth flow path 58d, it flows (i.e., falls) into the fifth flow path 58e positioned below through a substantially circular opening 58o provided on the lower surface of the downstream end. In the fifth flow path 58e, unlike the first flow path 58a to the fourth flow path 58d, there is no gas layer, and the fifth flow path 58e is contained in the liquid filling the fifth flow path 58e. There are slight bubbles in the vicinity of the upper surface.
　加圧液生成部５３では、加圧液生成容器５８の流路５８ａ～５８ｅを、段階的に緩急を繰り返しつつ上から下に流れ落ちる（すなわち、水平方向への流れと下方向への流れとを交互に繰り返しつつ流れる）混合流体５９において、気体が液体に徐々に加圧溶解する。第５流路５８ｅにおいては、液体中に溶解している気体の濃度は、加圧環境下における当該気体の（飽和）溶解度の６０％～９０％にほぼ等しい。そして、液体に溶解しなかった余剰の気体が、第５流路５８ｅ内において、視認可能な大きさの気泡として存在している。 In the pressurizing liquid generating unit 53, the flow paths 58a to 58e of the pressurizing liquid generating container 58 flow down from the top to the bottom while repeating the steps gradually (that is, the flow in the horizontal direction and the flow in the downward direction are reduced). In the mixed fluid 59 (flowing alternately and repeatedly), the gas is gradually dissolved in the liquid under pressure. In the fifth flow path 58e, the concentration of the gas dissolved in the liquid is substantially equal to 60% to 90% of the (saturated) solubility of the gas under a pressurized environment. And the excess gas which was not melt | dissolved in the liquid exists as a bubble of the magnitude | size which can be visually recognized in the 5th flow path 58e.
　加圧液生成容器５８は、第５流路５８ｅの下流側の上面から上方へと延びる余剰気体分離部５８ｆをさらに備え、余剰気体分離部５８ｆには混合流体５９が充満している。余剰気体分離部５８ｆの上下方向に垂直な断面は略矩形であり、余剰気体分離部５８ｆの上端部は、圧力調整用の絞り部５８ｇを介して補助配管５４ｂに接続される。第５流路５８ｅを流れる混合流体５９の気泡は、余剰気体分離部５８ｆ内を上昇して混合流体５９の一部と共に補助配管５４ｂに流れ込む。 The pressurized liquid generating container 58 further includes a surplus gas separation part 58f extending upward from the upper surface on the downstream side of the fifth flow path 58e, and the surplus gas separation part 58f is filled with the mixed fluid 59. The cross section perpendicular to the vertical direction of the surplus gas separation portion 58f is substantially rectangular, and the upper end portion of the surplus gas separation portion 58f is connected to the auxiliary pipe 54b via a pressure adjusting throttle portion 58g. The bubbles of the mixed fluid 59 flowing through the fifth flow path 58e rise in the surplus gas separation portion 58f and flow into the auxiliary pipe 54b together with a part of the mixed fluid 59.
　このようにして、混合流体５９の余剰な気体が混合流体５９の一部と共に分離されることにより、少なくとも容易に視認できる大きさの気泡を実質的に含まない加圧液５６が生成され、第５流路５８ｅの下流側の端部に接続された送出配管５４ａへと送出される。本実施の形態では、加圧液５６には、大気圧下における気体の（飽和）溶解度の約２倍以上の気体が溶解している。加圧液生成容器５８において流路５８ａ～５８ｅを流れる混合流体５９の液体は、生成途上の加圧液５６と捉えることもできる。補助配管５４ｂに流入した混合流体５９は、液貯留部５５内の対象液５１へと導かれる。補助配管５４ｂは、長時間ポンプ５４ｄを稼働した場合における対象液５１の減少を防止するための補助流路として機能する。 In this manner, the excess gas of the mixed fluid 59 is separated together with a part of the mixed fluid 59, thereby generating a pressurized liquid 56 substantially free of bubbles having a size that can be easily visually recognized. It is sent to a delivery pipe 54a connected to the downstream end of the five flow path 58e. In the present embodiment, the pressurized liquid 56 dissolves a gas that is about twice or more the gas (saturated) solubility under atmospheric pressure. The liquid of the mixed fluid 59 flowing through the flow paths 58a to 58e in the pressurized liquid generating container 58 can be regarded as the pressurized liquid 56 that is being generated. The mixed fluid 59 that has flowed into the auxiliary pipe 54 b is guided to the target liquid 51 in the liquid reservoir 55. The auxiliary pipe 54b functions as an auxiliary flow path for preventing a decrease in the target liquid 51 when the pump 54d is operated for a long time.
　第１流路５８ａの上方には、排気弁６１も設けられる。排気弁６１は、ポンプ５４ｄの停止時に開放され、混合流体５９が混合ノズル５７へと逆流することを防止する。 An exhaust valve 61 is also provided above the first flow path 58a. The exhaust valve 61 is opened when the pump 54 d is stopped, and prevents the mixed fluid 59 from flowing back to the mixing nozzle 57.
　微細気泡生成ノズル５２は、加圧液流入口から加圧液噴出口に向かって順に連続して配置される導入部と、テーパ部と、喉部とを備える。導入部では、流路面積は、ノズル流路０の中心軸方向の各位置においてほぼ一定である。テーパ部では、加圧液５６の流れる方向に向かって（すなわち、下流側に向かって）流路面積が漸次減少する。テーパ部の内面は、ノズル流路の中心軸を中心とする略円錐面の一部である。当該中心軸を含む断面において、テーパ部の内面の成す角度は、１０°以上９０°以下であることが好ましい。 The fine bubble generating nozzle 52 includes an introduction portion, a taper portion, and a throat portion that are sequentially arranged from the pressurized liquid inflow port toward the pressurized liquid ejection port. In the introduction portion, the flow channel area is substantially constant at each position in the central axis direction of the nozzle flow channel 0. In the tapered portion, the flow path area gradually decreases in the direction in which the pressurized liquid 56 flows (that is, toward the downstream side). The inner surface of the tapered portion is a part of a substantially conical surface centered on the central axis of the nozzle channel. In the cross section including the central axis, the angle formed by the inner surface of the tapered portion is preferably 10 ° or more and 90 ° or less.
　喉部は、テーパ部と加圧液噴出口とを連絡する。喉部の内面は略円筒面であり、喉部では、流路面積はほぼ一定である。喉部における流路断面の直径は、ノズル流路において最も小さく、喉部の流路面積は、ノズル流路において最も小さい。加圧液５６が喉部を通過することにより加圧液生成部５３の内部は加圧環境となっているが、喉部を通過した加圧液５６が急減圧されることで、加圧液５６内に溶解していた気体が気泡として生成されるとともに、減圧時の剪断力によって気泡が微細化される。 The throat communicates with the tapered part and the pressurized liquid spout. The inner surface of the throat is a substantially cylindrical surface, and the channel area is substantially constant at the throat. The diameter of the cross section of the channel in the throat is the smallest in the nozzle channel, and the channel area of the throat is the smallest in the nozzle channel. As the pressurized liquid 56 passes through the throat part, the inside of the pressurized liquid generating part 53 is in a pressurized environment. The gas dissolved in 56 is generated as bubbles, and the bubbles are refined by the shearing force during decompression.
　気泡生成装置５０の構造は様々に変更されてよく、さらには、異なる構造のものが使用されてもよい。例えば、微細気泡生成ノズル５２は、複数の加圧液噴出口を備えてもよい。微細気泡生成ノズル５２と加圧液生成部５３との間に圧力調整弁が設けられ、微細気泡生成ノズル５２に与えられる圧力が高精度にて一定に維持されてもよい。加圧液生成容器５８の流路の断面形状は、円形でもよい。気体と液体との混合には、機械的攪拌等の他の手段が利用されてもよい。 The structure of the bubble generating device 50 may be variously changed, and further, a structure having a different structure may be used. For example, the fine bubble generating nozzle 52 may include a plurality of pressurized liquid ejection ports. A pressure regulating valve may be provided between the fine bubble generating nozzle 52 and the pressurized liquid generating unit 53, and the pressure applied to the fine bubble generating nozzle 52 may be kept constant with high accuracy. The cross-sectional shape of the flow path of the pressurized liquid generating container 58 may be circular. Other means such as mechanical stirring may be used for mixing the gas and the liquid.
　（４）前述の実施形態では、気泡液の濃縮を行う際に液体を循環させる方式の気泡液濃縮装置の例を示したが、それに限らず濃縮側流路を気泡生成装置５０へ循環させて、気泡液の生成と濃縮を繰り返す方式の高密度微細気泡液生成装置であってもよい。 (4) In the above-described embodiment, the example of the bubble liquid concentrating device that circulates the liquid when concentrating the bubble liquid has been described. Alternatively, a high-density fine bubble liquid generation device that repeats generation and concentration of bubble liquid may be used.
　例えば、図７の配管４１を図８における気泡生成装置５０の戻し配管５４ｃへ接続し、濃縮液９が混合ノズル５７へ再度供給されるようにしてもよい。
また、配管４１を気泡生成装置５０の液貯留部５５へ循環させてもよい。この場合、加圧状態であった濃縮側流路が減圧されることを利用し、配管４１の液貯留部５５側に微細気泡生成ノズル（図示せず）を設けて減圧し、濃縮液９内の気泡を剪断力によりさらに微細化させてもよく、濃縮側流路を加圧状態とする弁３９の代わりとして微細気泡生成ノズルを配置してもよい。 For example, the pipe 41 in FIG. 7 may be connected to the return pipe 54 c of the bubble generating device 50 in FIG. 8 so that the concentrate 9 is supplied again to the mixing nozzle 57.
Further, the pipe 41 may be circulated to the liquid storage unit 55 of the bubble generating device 50. In this case, utilizing the fact that the concentrated flow path that has been in a pressurized state is depressurized, a fine bubble generating nozzle (not shown) is provided on the liquid storage section 55 side of the pipe 41 to depressurize, and the concentrated liquid 9 These bubbles may be further refined by a shearing force, and a fine bubble generating nozzle may be arranged in place of the valve 39 for bringing the concentration side flow path into a pressurized state.
　以下、実施例および比較例を挙げて本発明を詳細に説明するが、本発明はこれら実施例に限定されるものではない。 Hereinafter, the present invention will be described in detail with reference to examples and comparative examples, but the present invention is not limited to these examples.
　（分離膜の作製例）
　ポリエステル製不織布（阿波製紙(株)製、７０ｇ／ｍ２、厚さ９０μｍ）上に、ポリスルホン（ソルベイアドバンストポリマーズ社製、Ｐ‐３５００）１８．３重量％とジメチルホルムアミド８１．７重量％の混合液を塗布した。その後、その混合液を塗布したポリエステル製不織布を２０℃の純水に浸漬し、さらに、４５℃の純水に浸漬した。このようにして、約１３０μｍの厚さのポリスルホン製多孔質膜を得た。 (Example of production of separation membrane)
A mixture of 18.3% by weight of polysulfone (manufactured by Solvay Advanced Polymers, P-3500) and 81.7% by weight of dimethylformamide on a nonwoven fabric made of polyester (Awa Paper Co., Ltd., 70 g / m 2 , thickness 90 μm). The liquid was applied. Thereafter, the polyester nonwoven fabric coated with the mixed solution was immersed in pure water at 20 ° C., and further immersed in pure water at 45 ° C. Thus, a polysulfone porous membrane having a thickness of about 130 μm was obtained.
　ここの分離膜は、膜の両面で平均孔径が異なる非対称膜であり、孔径が小さい方の表面の平均孔径は、２０ｎｍであった。なお、平均孔径は、ＳＥＭの表面観察から読み取ることにより測定した（以下、同様）。 The separation membrane here is an asymmetric membrane with different average pore sizes on both sides of the membrane, and the average pore size on the surface with the smaller pore size was 20 nm. The average pore diameter was measured by reading from the surface observation of SEM (hereinafter the same).
　＜実施例１＞
　分離膜の作製例で得られたポリスルホン製多孔質膜を、メタクリル酸水溶液（濃度８０ｗｔ％）中に浸漬させた後取出し、加速電圧２５０ｋＶ、照射線量３０ｋＧｙ、窒素雰囲気下（酸素濃度３００ｐｐｍ以下）、室温で電子線照射して、メタクリル酸を基材にグラフト重合させた。次いで、基材と未反応のメタクリル酸のモノマーとポリマーを除去するため、６０℃の温水で２時間浸漬洗浄を行い、４０℃の乾燥機で２時間乾燥させて、実施例１の気泡液濃縮用分離膜（後述する表１で「グラフト膜」と示す）を得た。この分離膜の孔径が小さい方の表面の平均孔径は、２０ｎｍであった。 <Example 1>
The polysulfone porous membrane obtained in the preparation example of the separation membrane was taken out after being immersed in an aqueous methacrylic acid solution (concentration 80 wt%), accelerated voltage 250 kV, irradiation dose 30 kGy, under nitrogen atmosphere (oxygen concentration 300 ppm or less), Electron beam irradiation was performed at room temperature, and methacrylic acid was graft-polymerized on the base material. Next, in order to remove the substrate and unreacted methacrylic acid monomer and polymer, immersion washing was performed for 2 hours in warm water at 60 ° C., followed by drying for 2 hours in a dryer at 40 ° C. Separation membrane (shown as “graft membrane” in Table 1 below) was obtained. The average pore diameter of the surface of the separation membrane having the smaller pore diameter was 20 nm.
　＜実施例２＞
　ｍ－フェニレンジアミン３．０ｇ、ラウリル硫酸ナトリウム０．１５ｇ、ベンゼンスルホン酸６．０ｇ、トリエチルアミン３．０ｇ、及び水８７．８５ｇを混合して水溶液（Ａ）を調製した。水溶液（Ａ）を分離膜の作製例で得られたポリスルホン製多孔質膜の上に塗布して、余分なアミン水溶液を除去した。次に、トリメシン酸クロライド０．２重量％を含むイソオクタン溶液を更に塗布した。その後、余分なイソオクタン溶液を除去して１００℃の乾燥器内で２分間保持することで、分離膜上にポリアミドからなるスキン層（厚さ約２００ｎｍ、非多孔質構造）を形成して、実施例２の気泡液濃縮用分離膜（後述する表１で「コーティング膜」と示す）を得た。 <Example 2>
An aqueous solution (A) was prepared by mixing 3.0 g of m-phenylenediamine, 0.15 g of sodium lauryl sulfate, 6.0 g of benzenesulfonic acid, 3.0 g of triethylamine, and 87.85 g of water. The aqueous solution (A) was applied on the polysulfone porous membrane obtained in the production example of the separation membrane, and the excess amine aqueous solution was removed. Next, an isooctane solution containing 0.2% by weight of trimesic acid chloride was further applied. After that, the excess isooctane solution is removed and held in a dryer at 100 ° C. for 2 minutes to form a polyamide skin layer (thickness: about 200 nm, non-porous structure) on the separation membrane. A separation membrane for bubbling liquid concentration of Example 2 (shown as “coating membrane” in Table 1 described later) was obtained.
　＜比較例１＞
　分離膜の作製例で得られたポリスルホン製多孔質膜を、表面処理することなく気泡液濃縮用分離膜（後述する表１で「ポリスルホン製膜」と示す）として使用した。 <Comparative Example 1>
The porous membrane made of polysulfone obtained in the production example of the separation membrane was used as a separation membrane for concentrating bubble liquid (shown as “polysulfone membrane” in Table 1 described later) without surface treatment.
　（水中での気泡接触角の測定）
　作製した実施例１～２及び比較例１の気泡液濃縮用分離膜を２５℃の純水に１０分間浸漬した後、自動接触角測定装置（共和界面科学株式会社製の商品名「ＤＭ－３００」）を用いて、気泡液濃縮用分離膜に付着している空気（気泡）の接触角を測定した。測定は、気泡の直径が４００～５００μｍのものを対象とし、Ｎ＝５回で行った。このとき気泡の供給をシリンジ針で行ないながら測定した。 (Measurement of bubble contact angle in water)
The produced separation membranes for concentrating bubble liquids of Examples 1 and 2 and Comparative Example 1 were immersed in pure water at 25 ° C. for 10 minutes, and then an automatic contact angle measuring device (trade name “DM-300 manufactured by Kyowa Interface Science Co., Ltd. )) Was used to measure the contact angle of air (bubbles) adhering to the separation membrane for bubbling liquid concentration. The measurement was conducted with N = 5 times for a bubble having a diameter of 400 to 500 μm. At this time, measurement was performed while supplying air bubbles with a syringe needle.
　（濃縮前後のＵＦＢ数密度の測定）
　図５に示す気泡液濃縮を用いて、気泡液の濃縮を行ない、ウルトラファインバブルの数密度を測定した。 (Measurement of UFB number density before and after concentration)
The bubble liquid was concentrated using the bubble liquid concentration shown in FIG. 5, and the number density of the ultra fine bubbles was measured.
　即ち、作製した平膜状の実施例１～２及び比較例１の気泡液濃縮用分離膜を所定の形状、サイズに切断し、平膜評価用のセル（日東電工株式会社製、Ｃ１０－Ｔ）にセットした。次いで、ウルトラファインバブル発生装置（ＩＤＥＣ株式会社製、ＦＺ１Ｎ－０２形）にて生成されたウルトラファインバブル水（気泡の最頻直径は、０．１μｍ、数密度１億個／ｍＬ）４Ｌが入ったタンクを準備し、気泡液濃縮用分離膜の孔径の小さい側（分離面側）に０．５ＭＰａの圧力、１Ｌ／ｍｉｎの流量でウルトラファインバブル原水を供給した。この操作によって原水タンクが０．４Ｌになるまでウルトラファインバブル原水を循環させながら濾過し、１０倍濃縮液を得た。 That is, the produced flat membrane-shaped separation membranes for concentrating bubbles in Examples 1 and 2 and Comparative Example 1 were cut into a predetermined shape and size, and a flat membrane evaluation cell (C10-T, manufactured by Nitto Denko Corporation) was cut. ). Next, 4L of ultra fine bubble water (moderate diameter of bubbles is 0.1μm and number density is 100 million / mL) generated by an ultra fine bubble generator (FEC1N-02, manufactured by IDEC Corporation) The tank was prepared, and ultrafine bubble raw water was supplied at a pressure of 0.5 MPa and a flow rate of 1 L / min to the side having a small pore diameter (separation surface side) of the separation membrane for bubbling liquid concentration. By this operation, filtration was performed while circulating the ultrafine bubble raw water until the raw water tank reached 0.4 L to obtain a 10-fold concentrated liquid.
　ウルトラファインバブル原水と１０倍濃縮液に含まれるウルトラファインバブルの数密度をナノ粒子解析装置（ナノサイト社製、ＮＳ５００）にてそれぞれ計測し、ウルトラファインバブルの数密度の増加率を算出した。 The number density of the ultra fine bubbles contained in the ultra fine bubble raw water and the 10-fold concentrated liquid was measured with a nanoparticle analyzer (Nanosite, NS500), and the increase rate of the number density of the ultra fine bubbles was calculated.
　実施例１～２及び比較例１に係る気泡液濃縮用分離膜の上記の測定の測定結果を表１に示す。
Figure JPOXMLDOC01-appb-T000001
 Table 1 shows the measurement results of the above measurements of the bubble liquid concentrating separation membranes according to Examples 1 and 2 and Comparative Example 1.
Figure JPOXMLDOC01-appb-T000001
　表１の結果が示すように、実施例１～２のように、表面処理によって、水中における気泡接触角が１４０°以上である分離膜を使用した場合には、気泡液濃縮の際に膜との接触により気泡が消失するのを抑制して、高濃度の気泡含有液を得ることができる。これに対して、分離膜として汎用されているポリスルホン製の分離膜を使用した場合、原液を１０倍に濃縮しても、殆どの気泡が消失することによって、高濃度の気泡含有液を得ることができなかった。 As shown in the results of Table 1, as in Examples 1 and 2, when a separation membrane having a bubble contact angle in water of 140 ° or more was used by surface treatment, It is possible to obtain a high-concentration bubble-containing liquid by suppressing the disappearance of bubbles due to contact. On the other hand, when a polysulfone separation membrane that is widely used as a separation membrane is used, even if the stock solution is concentrated 10 times, most of the bubbles disappear, thereby obtaining a high-concentration bubble-containing liquid. I could not.
　＜実施例３＞
　実施例１において、分離膜の作製例で得られたポリスルホン製多孔質膜（グラフト未処理品）を用いて、ポリビニルアルコール（クラレ(株)社製、製品名ＫＭ－１１８）により表面処理（コーティング）したこと以外は、実施例１と全く方法で気泡液濃縮用分離膜（気泡接触角１５５°）を作製し、濃縮前後のＵＦＢ数密度の測定を行った。その結果、１０倍濃縮時のＵＦＢ数密度の増加率は、３．７倍であった。なお、ポリビニルアルコールによるコーティングは次のようにして行った。 <Example 3>
In Example 1, the polysulfone porous membrane (ungrafted product) obtained in the separation membrane preparation example was used for surface treatment (coating, product name KM-118, manufactured by Kuraray Co., Ltd.). Except for the above, a separation membrane for concentrating bubble liquid (bubble contact angle 155 °) was prepared in the same manner as in Example 1, and the UFB number density before and after concentration was measured. As a result, the rate of increase in UFB number density upon 10-fold concentration was 3.7 times. The coating with polyvinyl alcohol was performed as follows.
　分離膜の作製例で得られたポリスルホン製多孔質膜（グラフト未処理品）を１０重量％のイソプロピルアルコール水溶液に浸漬して湿潤状態とした後、ポリスルホン膜側にポリビニルアルコール０．０５重量％の水溶液を塗布して、８０℃のオーブンにて乾燥させた。 The polysulfone porous membrane (ungrafted product) obtained in the preparation example of the separation membrane was dipped in a 10% by weight isopropyl alcohol aqueous solution to be in a wet state, and then 0.05% by weight polyvinyl alcohol on the polysulfone membrane side. The aqueous solution was applied and dried in an oven at 80 ° C.
　＜比較例２～４＞
　疎水性のポリエーテルスルホン製分離膜（平均孔径１０ｎｍ、接触角７５°）、ポリフッ化ビニリデン製分離膜（平均孔径５００ｎｍ、接触角５６°）、エポキシ樹脂製分離膜（平均孔径５０ｎｍ、接触角１１０°）を、それぞれ表面処理することなく気泡液濃縮用分離膜として使用した。 <Comparative Examples 2 to 4>
Hydrophobic polyethersulfone separation membrane (average pore size 10 nm, contact angle 75 °), polyvinylidene fluoride separation membrane (average pore size 500 nm, contact angle 56 °), epoxy resin separation membrane (average pore size 50 nm, contact angle 110) Were used as a separation membrane for bubbling liquid concentration without any surface treatment.
　濃縮前後のＵＦＢ数密度の測定を行った結果、１０倍～５０倍濃縮時のＵＦＢ数密度の増加率は、いずれも２倍未満であった。 As a result of measuring the UFB number density before and after the concentration, the increase rate of the UFB number density at the time of concentration 10 to 50 times was less than 2 times.
１　　膜エレメント
２　　分離膜
３　　透過側流路材
４　　封筒状膜
５　　中心管
６　　供給側流路材
７　　供給液
８　　透過液
９　　濃縮液
３０　膜モジュール
３１　容器
５０　気泡生成装置 DESCRIPTION OF SYMBOLS 1 Membrane element 2 Separation membrane 3 Permeate side channel material 4 Envelope-shaped membrane 5 Center tube 6 Supply side channel material 7 Supply liquid 8 Permeate 9 Concentrate 30 Membrane module 31 Container 50 Bubble generation device

Claims (8)

  1. 　分離膜により気泡を含有した供給液中の気泡を高濃度化する気泡液濃縮装置において、
    　前記分離膜は、少なくとも一方の表面について、水中における気泡接触角が１４０°以上であることを特徴とする気泡液濃縮装置。     In the bubble liquid concentrating device for increasing the concentration of bubbles in the supply liquid containing bubbles by the separation membrane,
    A bubble liquid concentrating device, wherein at least one surface of the separation membrane has a bubble contact angle in water of 140 ° or more.
  2. 　前記供給液には、直径１μｍ未満の気泡が含まれている請求項１記載の気泡液濃縮装置。 The bubble liquid concentrating device according to claim 1, wherein the supply liquid contains bubbles having a diameter of less than 1 µm.
  3. 　前記分離膜は、前記一方の表面が、平均孔径１，０００ｎｍ以下の多孔質構造、又は非多孔質構造である請求項１又は２に記載の気泡液濃縮装置。 3. The bubble liquid concentrator according to claim 1, wherein the one surface of the separation membrane has a porous structure or a non-porous structure having an average pore diameter of 1,000 nm or less.
  4. 　前記分離膜は、前記一方の表面に、親水性を有するポリマー多孔質層又は非多孔質層を有する請求項１～３いずれかに記載の気泡液濃縮装置。 4. The bubble liquid concentrating device according to claim 1, wherein the separation membrane has a hydrophilic polymer porous layer or a non-porous layer on the one surface.
  5. 　前記分離膜を有する膜エレメントと、その膜エレメントを収容して濃縮側流路と透過側流路とを形成する容器とを含む膜モジュールを備える請求項１～４いずれかに記載の気泡液濃縮装置。 The bubble liquid concentration according to any one of claims 1 to 4, further comprising a membrane module including a membrane element having the separation membrane and a container that accommodates the membrane element and forms a concentration side channel and a permeation side channel. apparatus.
  6. 　前記膜エレメントは、前記分離膜の一方の膜面に沿って前記供給液が流動しながら、透過液を前記分離膜の他方の膜面側に透過させる構造である請求項５に記載の気泡液濃縮装置。 The bubble liquid according to claim 5, wherein the membrane element has a structure that allows a permeate to permeate to the other membrane surface side of the separation membrane while the supply liquid flows along one membrane surface of the separation membrane. Concentrator.
  7. 　前記膜モジュールから排出された濃縮液を供給液に戻す循環流路を備える請求項５又は６に記載の気泡液濃縮装置。 The bubble liquid concentrator according to claim 5 or 6, further comprising a circulation channel for returning the concentrated liquid discharged from the membrane module to the supply liquid.
  8. 　請求項１～７いずれかに記載の気泡液濃縮装置と、その気泡液濃縮装置に直径１μｍ未満の気泡を含む供給液を供給する気泡生成装置と、を備える高密度微細気泡液生成装置。
          A high-density fine bubble liquid generating apparatus comprising: the bubble liquid concentrating apparatus according to any one of claims 1 to 7; and a bubble generating apparatus for supplying a supply liquid containing bubbles having a diameter of less than 1 μm to the bubble liquid concentrating apparatus.
PCT/JP2016/080426 2015-10-29 2016-10-13 Bubble liquid concentration device, and device for generating highly dense fine bubble liquid WO2017073346A1 (en)

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JP2009148673A (en) * 2007-12-19 2009-07-09 Sekisui Chem Co Ltd Membrane separation apparatus and desalination method
JP2011131117A (en) * 2009-12-22 2011-07-07 Mitsubishi Materials Corp Microbubble concentrator, microbubble generating apparatus, method of concentrating microbubble and method of generating microbubble
JP2014155920A (en) * 2013-01-17 2014-08-28 Idec Corp High density fine air bubble liquid generation method and high density fine air bubble liquid generation device

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Publication number Priority date Publication date Assignee Title
JP2009148673A (en) * 2007-12-19 2009-07-09 Sekisui Chem Co Ltd Membrane separation apparatus and desalination method
JP2011131117A (en) * 2009-12-22 2011-07-07 Mitsubishi Materials Corp Microbubble concentrator, microbubble generating apparatus, method of concentrating microbubble and method of generating microbubble
JP2014155920A (en) * 2013-01-17 2014-08-28 Idec Corp High density fine air bubble liquid generation method and high density fine air bubble liquid generation device

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