Adsorbent-filled column and liquid purification apparatus

Abstract

To provide an adsorbent-filled column and a liquid purifier which are highly clean, do not build up static electricity, and are particularly suitable for semiconductor manufacturing processes.SOLUTION: Provided are an adsorbent-filled column and a liquid purifier including the same, the column being filled with a porous adsorbent inside a container, which container is made of a fluororesin, has liquid passage holes on an upstream side and a downstream side thereof, and has a conductive material in at least part of outer surfaces thereof and / or in the fluororesin forming the container. Preferably, the fluororesin is a perfluoroalkoxyethylene polymer or polytetrafluoroethylene, the conductive material is one or more selected from the group consisting of carbon black, carbon fiber, graphite, coke, and fine metal powder, and the adsorbent is one or more selected from the group consisting of ion exchanger having ion exchange groups, zeolite, activated carbon, and synthetic adsorbent.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention particularly relates to an adsorbent-packed column and a liquid purification apparatus suitable for a semiconductor manufacturing process.

Background Art

[0002] In order to reduce the metal impurity concentration in an organic solvent to the ppt level, ion exchange resins and ion adsorption membranes are effective in reducing metal impurities, and it is particularly effective to purify in combination with a particulate removal filter for removing nonionic particulate impurities (Patent Document 1).

[0003] On the other hand, when a non-conductive substance (such as an organic solvent or ultrapure water) or gas flows through a PFA pipe or tube at a high flow rate, static electricity accumulates inside. Particularly in the semiconductor manufacturing process, the accumulation of static electricity in the fluid circuit and the electrostatic discharge to the circuit must be avoided. However, since semiconductor-grade organic solvents and ultrapure water contain almost no conductive substances, it is a problem that static electricity easily accumulates in the fluid circuit. For example, Patent Document 2 reports a technique of imparting conductivity by containing a conductive fluoropolymer yarn (a mixture of carbon and PFA) inside a particulate removal filter.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] As described above, in the semiconductor manufacturing process, avoiding the accumulation of static electricity in the fluid circuit and the electrostatic discharge to the circuit is an important issue. Although there are conductive substances in the fine particle removal filter, there are no conductive columns or cartridges in the purification using ion exchange resins. As an example of the configuration of a conductive column or cartridge, a column with a fluororesin coated on the inner surface of a SUS container can be considered, but it is not preferable in terms of weight and usability. Also, in the semiconductor manufacturing process, since columns made of fluororesin are mainly used in terms of cleanliness, fluororesin is most preferable for the container filled with ion exchange resin. Therefore, an object of the present invention is to provide an adsorbent-filled column and a liquid purification apparatus that have a high degree of cleanliness, do not accumulate static electricity, and are particularly suitable for the semiconductor manufacturing process.

Means for Solving the Problems

[0006] The above object is achieved by the following [1] to [8]. [1] A column filled with a porous adsorbent inside a container, The The container is made of fluororesin, The The container of Has liquid passage holes on the upstream side and the downstream side, conductive material is provided in the The container of At least a part of the outer surface , and at least a part of the conductive material is connected from the upper end to the lower end of the container. Adsorbent-filled column. [2] The adsorbent-filled column according to [1] above, wherein the fluororesin is a perfluoroalkoxyethylene polymer or polytetrafluoroethylene. [3] The adsorbent-filled column according to [1] or [2] above, wherein the conductive substance is one or more selected from the group consisting of carbon black, carbon fiber, graphite, coke, and metal fine powder. [4] The adsorbent-filled column according to any one of [1] to [3] above, wherein the adsorbent is one or more selected from the group consisting of ion exchangers, zeolites, activated carbon, and synthetic adsorbents. [5] The adsorbent-filled column according to any one of [1] to [4] above, wherein the upstream side and the downstream side of the container have joints for connecting to other members, and the joints have outflow prevention members for the adsorbent. [6] The adsorbent-filled column according to any one of [1] to [5] above, which is in the form of a cartridge. [7] A liquid purification apparatus comprising the adsorbent-filled column according to any one of [1] to [6] above. [8] The liquid purification apparatus according to [7] above, which has a filter for capturing fine particles.

Effect of the Invention

[0007] According to the present invention, it is possible to provide an adsorbent-filled column and a liquid purification apparatus that have a high degree of cleanliness, do not accumulate static electricity, and are particularly suitable for semiconductor manufacturing processes.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Mode for Carrying Out the Invention

[0009] The adsorbent-packed column of the present invention can, if necessary, be combined with a particulate-trapping filter and used preferably for purifying non-conductive substances (such as organic solvents and ultrapure water) or gases, particularly when attached to a liquid purification device or the like, to obtain pure water, ultrapure water, or the pre-stage treated water for obtaining such pure water. The adsorbent-packed column attached to a liquid purification device or the like can purify a liquid by passing the liquid to be purified through the column and adsorbing impurities onto the adsorbent in the column. Regarding the present invention, "pure water" refers to water having a resistivity (at 25°C) of generally 0.1 MΩ·cm or more, and "ultrapure water" refers to water having a resistivity exceeding 15 MΩ·cm or exceeding 18 MΩ·cm.

[0010] The liquid (water to be treated) to be purified by the liquid purification device equipped with the adsorbent-packed column is arbitrary and may be water or an aqueous solution, or may be an organic solvent (non-aqueous liquid) such as IPA (isopropyl alcohol), PGMEA (propylene glycol monomethyl ether acetate), PGME (propylene glycol monomethyl ether), PGEE (propylene glycol monoethyl ether), etc. The liquid to be purified may be a mixture of water and the above organic solvent, a solution in which a polymer or the like is dissolved in water or a solvent, or an acid or alkali aqueous solution. Alternatively, the liquid purification device can be used, for example, as a household water purifier for obtaining purified water at home.

[0011] Hereinafter, embodiments for carrying out the present invention (hereinafter referred to as embodiments) will be described with reference to the drawings. However, the present invention is not limited to these embodiments.

[0012] FIG. 1 is a schematic diagram of an adsorbent-packed column 1 according to an embodiment of the present invention, FIG. 2 is a schematic diagram showing the joint portion between the container and the joint of the adsorbent-packed column shown in FIG. 1 disassembled, and FIG. 3 is a schematic diagram showing the joint of the adsorbent-packed column shown in FIG. 1 disassembled. As shown in FIG. 1, the adsorbent-packed column 1 includes a porous adsorbent 2 and a fluororesin container 3 filled with the adsorbent 2. On the upstream and downstream sides of the container 3, liquid passage holes 7 and 8 through which the liquid to be purified passes are provided. For example, in the direction shown by the arrow in FIG. 1, that is, the liquid to be purified is supplied from the upstream side of the column container 3 through the liquid passage hole 7, purified in the column container 3, and the liquid flows out from the downstream liquid passage hole 8. It may be in a downflow format, or in the direction opposite to the arrow in FIG. 1, that is, the liquid to be purified is supplied from the downstream liquid passage hole 8 of the column container 3, purified in the column container 3, and the liquid to be purified flows out through the upstream liquid passage hole 7. It may be in an upflow format. The joining of the column container 3 to the joint 5 for joining to other members is not particularly limited. For example, as shown in FIGS. 1 and 2, sleeves 9 are inserted on the upstream and downstream sides of the column container 3 respectively, and the joint 5 and nuts 6 enable the joining of the upstream and downstream sides of the column container 3 to the joint 5. Examples of such joints include the mode shown in FIG. 3, in which two threaded portions 52 and 53 and an outflow prevention member 51 for the adsorbent are sandwiched therebetween. The outflow prevention member 51 for the adsorbent is formed of a mesh plate 511 and a mesh 512, thereby preventing the outflow of the adsorbent 2. The sizes of the threaded portions 52 and 53 are appropriately adjusted as required, and they may be the same size or different sizes. The mesh plate 511 forming the outflow prevention member 51 for the adsorbent is installed to hold down and fix the mesh 512, and holes of a size that do not inhibit the flow of the liquid to be purified are formed. On the other hand, the mesh 512 is installed to prevent the outflow of the adsorbent filled in the column, and the mesh opening is preferably 30 to 350 μm. Depending on the particle size of the adsorbent filled in the column, as shown in FIG. 4, only the mesh plate 511 provided with slit-shaped or lattice-shaped gaps without a mesh may be used to prevent the outflow of the adsorbent. The opening of the slit and the lattice is preferably not more than 1 / 2 of the average particle size of the adsorbent. As shown in Fig. 5, the joining of the column container 3 and the joint 5 can be achieved by flaring the tip portions 31 on the upstream and downstream sides of the column container (heating the tip portion 31 with a heat gun to a temperature at which the tip portion 31 undergoes plastic deformation), and at the timing when the tip portion 31 of the column container 3 undergoes plastic deformation, pressing so that the outflow prevention member 51 of the joint 5, which has the outflow prevention member 51 of the adsorbent provided at one end, enters the inside of the tip portion 31, and the column container 3 can be joined to the joint 5. The tip 31 of the column container 3 is widened by the flaring process, preventing the nut from falling off. In this case, both the mesh plate 511 and the mesh 512 constituting the outflow prevention member 51 of the joint 5 need to be sized to fit inside the flared column container 3. Also, on the side opposite to the outflow prevention member 51 of the joint 5, a threaded portion 54 for connecting to other members may be provided. This threaded portion 54 may be configured integrally with the joint 5 or may be separable from the joint 5, and is not particularly limited. The column container 3 has a conductive substance 4. The conductive substance 4 provided in the column container 3 prevents the accumulation of static electricity generated by flowing a non-conductive substance (such as an organic solvent or ultrapure water) or gas at a high flow rate inside the column container 3 formed of a fluororesin. The conductive substance 4 may be provided on at least a part or all of the outer surface of the column container 3, may be contained in the fluororesin forming the column container 3, or may be both. However, the conductive substance needs not to come into contact with the purification target flowing through the column container 3. As an aspect in which the conductive substance 4 is provided on at least a part of the outer surface of the column container 3, as shown in Fig. 6 it may be an aspect in which the conductive substance 4 is provided in a stripe shape, or as shown in Fig. 7 it may be an aspect in which the conductive substance 4 is provided in a ladder shape. The aspect of the conductive substance is not particularly limited.

[0013] The porous adsorbent 2 may be one selected from the group consisting of an ion exchanger, zeolite, activated carbon, and a synthetic adsorbent, or may be composed of a combination of two or more arbitrarily selected from the group consisting of an ion exchanger, zeolite, activated carbon, and a synthetic adsorbent.

[0014] The ion exchanger is, for example, a granular ion exchange resin such as a granular cation exchange resin, a granular chelating resin, a granular anion exchange resin, a combination of a granular cation exchange resin, a granular chelating resin, and a granular anion exchange resin, a monolithic organic porous cation exchanger, a monolithic organic porous chelating exchanger, a monolithic organic porous anion exchanger, a monolithic organic porous ion exchanger such as a combination of a monolithic organic porous cation exchanger, a monolithic organic porous chelating exchanger, and a monolithic organic porous anion exchanger, or a combination of a granular ion exchange resin and a monolithic organic porous ion exchanger. When the ion exchanger is a combination of a granular cation exchange resin, a granular chelating resin, and a granular anion exchange resin, it may be used as a mixed bed in which the granular cation exchange resin, the granular chelating resin, and the granular anion exchange resin are uniformly mixed, or on the upstream side of the filling region of the ion exchanger, the granular cation exchange resin and / or the granular chelating resin are filled, and on the downstream side of the filling region of the ion exchanger, the granular anion exchange resin is filled, or on the upstream side of the filling region of the ion exchanger, the granular anion exchange resin is filled, and on the downstream side of the filling region of the ion exchanger, the granular cation exchange resin and / or the granular chelating resin are filled and used as a multi-bed. Also, when the ion exchanger is a combination of a monolithic organic porous cation exchanger and a monolithic organic porous anion exchanger, on the upstream side of the filling region of the ion exchanger, the monolithic organic porous cation and / or the monolithic organic porous chelating exchanger are filled, and on the downstream side of the filling region of the ion exchanger, the monolithic organic porous anion exchanger is filled, or on the upstream side of the filling region of the ion exchanger, the monolithic organic porous anion exchanger is filled, and on the downstream side of the filling region of the ion exchanger, the monolithic organic porous cation exchanger and / or the monolithic organic porous chelating exchanger are filled and used as a multi-bed. When the ion exchanger is a combination of a granular ion exchange resin and a monolithic organic porous ion exchanger, on the upstream side of the filling region of the ion exchanger, the monolithic organic porous ion exchanger is filled, and on the downstream side of the filling region of the ion exchanger, the granular ion exchange resin is filled.

[0015] The granular cation exchange resin may be a strongly acidic cation exchange resin, a weakly acidic cation exchange resin, a chelating resin, or a combination thereof. Examples of the strongly acidic cation exchange resin include Orlite DS-1, Orlite DS-4, XSC-1415HG, etc. Examples of the weakly acidic cation exchange resin include Amberlite® IRC76, etc. Examples of the chelating resin include Orlite DS-21, DS-22, etc. In order to reduce the cationic impurities in the liquid to be treated, it is desirable to use the cation exchange resin in the H form.

[0016] The granular anion exchange resin may be a strongly basic anion exchange resin, a weakly basic anion exchange resin, or a combination thereof. Examples of the strongly basic anion exchange resin include Orlite DS-2, Orlite DS-5, XSA-2415HG, etc. Examples of the weakly basic anion exchange resin include Orlite DS-6. Examples of the boron-selective anion exchange resin having a glucamine group as a functional group include Amberlite® IRA743. In order to reduce the anionic impurities in the liquid to be treated, it is desirable to use the anion exchange resin in the OH form. However, when carbonic acid does not become an impurity, it can be used in the carbonate form or the bicarbonate form.

[0017] Also, the ion exchanger may be these mixed-bed ion exchangers. Examples of the mixed-bed ion exchange resin, which is a mixture of a granular strongly acidic cation exchange resin (cation exchange resin) and a granular strongly basic anion exchange resin (anion exchange resin), include Orlite DS-3, Orlite DS-7, XSM-N411HG, etc.

[0018] The average particle size of the granular ion exchanger is not particularly limited, but is preferably 200 to 1000 μm, particularly preferably 300 to 800 μm. The average particle size of the ion exchanger is a value measured by a laser diffraction particle size distribution measuring device.

[0019] The monolithic organic porous ion exchanger is not particularly limited as long as an ion exchange group is introduced into the monolithic organic porous body. For example, the following monolithic organic porous ion exchangers can be mentioned.

[0020] Examples of the monolithic organic porous ion exchanger include those composed of a continuous skeleton phase and a continuous pore phase, where the thickness of the continuous skeleton is 1 to 100 μm, the average diameter of the continuous pores is 1 to 1000 μm, the total pore volume is 0.5 to 50 mL / g, a cation exchange group or an anion exchange group is introduced, the ion exchange capacity per weight in the dry state is 1 to 6 meq / g, and the ion exchange groups are uniformly distributed in the monolithic organic porous ion exchanger (hereinafter, also referred to as the monolithic organic porous ion exchanger of the first form).

[0021] In addition, examples of the monolithic organic porous ion exchanger of the first form include a continuous macroporous structure in which bubble-like macropores overlap with each other and the overlapping part forms an opening with an average diameter of 30 to 300 μm, the total pore volume is 0.5 to 10 ml / g, a cation exchange group or an anion exchange group is introduced, the ion exchange capacity per weight in the dry state is 1 to 6 meq / g, the ion exchange groups are uniformly distributed in the monolithic organic porous ion exchanger, and in the SEM image of the cross section of the continuous macroporous structure (dry body), the area of the skeleton part appearing in the cross section is 25 to 50% of the image area.

[0022] In addition, as the monolithic organic porous ion exchanger of the first form, the monolithic organic porous ion exchanger is composed of an aromatic vinyl polymer containing 0.1 to 5.0 mol% of crosslinked structural units in all constituent units into which ion exchange groups are introduced, and has a three-dimensionally continuous skeleton with an average thickness of 1 to 60 μm, and a co-continuous structure composed of three-dimensionally continuous pores with an average diameter of 10 to 200 μm between the skeletons. The total pore volume is 0.5 to 10 mL / g, a cation exchange group or an anion exchange group is introduced, the ion exchange capacity per weight in the dry state is 1 to 6 meq / g, and the ion exchange groups are uniformly distributed in the organic porous ion exchanger. Examples of the monolithic organic porous ion exchanger include those satisfying the above conditions.

[0023] When the particles are composed of an ion exchanger, the liquid to be treated (liquid) is, for example, IPA (isopropyl alcohol), PGMEA (propylene glycol monomethyl ether acetate), PGME (propylene glycol monomethyl ether), PGEE (propylene glycol monoethyl ether), NMP (N-methyl-2-pyrrolidone). An aqueous solution showing acidity to alkalinity may also be used as the liquid to be treated (liquid). The impurities removed in the liquid to be treated (liquid) are, for example, metal ions such as Li, Na, Mg, Al, K, Ca, Cr, Mn, Fe, Co, Ni, Cu, Cd, Pb, anions such as Cl, SO4, NO3, PO4, CO3, HCO3, organic acids such as formic acid, acetic acid, maleic acid, propionic acid, and high molecular compounds with positive or negative charges.

[0024] Examples of the zeolite include one or more selected from crystalline zeolites. Examples of the crystalline zeolite include one or more crystalline zeolites selected from A-type, Y-type, X-type, chabazite, ferrierite, ZSM-5, and clinoptilolite.

[0025] Furthermore, it is preferable that the crystalline zeolite has an Si / Al molar ratio of 1 to 5 that constitutes the crystalline zeolite. When the Si / Al molar ratio is within the above range, it is structurally stable and has an appropriate cation content, and can suitably adsorb and remove impurities in the liquid to be treated.

[0026] The above crystalline zeolite may be one in which the cations are exchanged with lithium ions, calcium ions, etc., or may not be exchanged.

[0027] As the above crystalline zeolite, spherical or cylindrical ones are preferable, and those with a diameter of 0.5 to 5 mm are preferable. When the diameter of the crystalline zeolite is within the above range, the liquid to be treated can be suitably impregnated without degrading the handleability.

[0028] The activated carbon is commercially available activated carbon. The diameter of the activated carbon particles is arbitrary. The activated carbon has micropores with a diameter of, for example, 0.7 nm to several tens of μm, and can physically remove organic impurities (organic acids, pigments, oils, etc.) in the liquid to be treated. Also, chlorine can be decomposed using the carbon component in the activated carbon. Examples of the activated carbon include carbonized phenolic resin. As the activated carbon, those obtained by carbonizing synthetic adsorbents or ion exchangers may also be used.

[0029] Examples of the synthetic adsorbent include styrene-divinylbenzene-based adsorbents, acrylic-based adsorbents, and phenolic-based adsorbents. Commercially available products of these adsorbents can also be used. Although not particularly limited as commercially available products, for example, synthetic adsorbents XAD2000, XAD4, FPX66, XAD1180N, XAD7HP, XAD-2 (all are trade names, manufactured by Organo Corporation), AMBERLITE (registered trademark, manufactured by DuPont), Diaion (registered trademark) HP20, HP21, Sepabeads (registered trademark) SP850, SP825L, SP700 (all are trade names, manufactured by Mitsubishi Chemical Corporation), carbonized phenolic resin (manufactured by MET Corporation), etc. can be mentioned.

[0030] Examples of the fluororesin forming the container include perfluoroalkoxyethylene polymer (PFA), polytetrafluoroethylene (PTFE), polytrifluorochloroethylene, copolymer of tetrafluoroethylene and perfluoroalkyl vinyl ether, copolymer of tetrafluoroethylene and hexafluoropropylene, terpolymer of tetrafluoroethylene, fluoroalkyl vinyl ether and hexafluoropropylene, etc. Among these, PFA or PTFE is particularly preferred in terms of particularly excellent heat resistance, chemical resistance, etc.

[0031] The conductive substance is preferably a conductive substance with low gas permeability, and it is particularly preferable to prevent impurities, volatile substances, ammonia, moisture, hydrofluoric acid, etc. in the gas from dissolving into the tube. From this perspective, one or more selected from the group consisting of carbon black, carbon fiber, graphite, coke and metal fine powder can be mentioned. Examples of the metal fine powder include boron nitride, copper, silver, etc.

[0032] The adsorbent-filled column of the present invention described above can be constructed by the following method. That is, a commercially available PFA pipe or tube (not containing a conductive substance) of the required length is prepared, and an adsorbent is filled therein. Next, sleeves are inserted using appropriate jigs on the upstream side and downstream side of the PFA pipe or tube. After inserting the sleeves, a tube cover containing a conductive substance (conductive tube cover) is attached from above the PFA pipe or tube. This conductive tube cover can also be replaced by attaching a conductive film or winding a conductive band. Alternatively, by using a PFA pipe or tube having a conductive substance on the inside and / or outer surface, the operation of attaching the conductive tube cover can be omitted. Note that the sleeves may be inserted after attaching the conductive tube cover. Then, it can be constructed by tightening the screw part of the joint having the outflow prevention member 51 of the adsorbent as shown in FIG. 3 or FIG. 4 with a nut. Moreover, the adsorbent-packed column of the present invention can also be provided in the form of a cartridge.

[0033] The adsorbent-packed column of the present invention obtained by the above construction method, particularly in the semiconductor manufacturing process, does not accumulate static electricity inside even though a fluororesin is used, and has a high cleanliness because it is made of fluororesin, and also has excellent handleability.

Explanation of Signs

[0034] 1 Adsorbent-packed column 2 Adsorbent 3 Container 31 Tip of the container 4 Conductive substance 5 Joint 6 Nut 7 Sleeve 8, 9 Liquid passage holes 51 Outflow prevention member for adsorbent 52, 53, 54 Threaded parts 511 Mesh plate 512 Mesh

Claims

1. A column filled with a porous adsorbent inside a container, wherein the container is made of a fluororesin, has liquid passage holes on the upstream side and the downstream side of the container, a conductive substance is provided on at least a part of the outer surface of the container, and at least a part of the conductive substance is connected from the upper end to the lower end of the container. The adsorbent-filled column.

2. The adsorbent-filled column according to claim 1, wherein the fluororesin is a perfluoroalkoxyethylene polymer or polytetrafluoroethylene.

3. The adsorbent-filled column according to claim 1 or 2, wherein the conductive substance is one or more selected from the group consisting of carbon black, carbon fiber, graphite, coke, and metal fine powder.

4. The adsorbent-filled column according to any one of claims 1 to 3, wherein the adsorbent is one or more selected from the group consisting of ion exchangers, zeolites, activated carbon, and synthetic adsorbents.

5. The adsorbent-filled column according to any one of claims 1 to 4, having joints for connecting to other members on the upstream side and the downstream side of the container, and the joints having outflow prevention members for the adsorbent.

6. The adsorbent-filled column according to any one of claims 1 to 5, which is in a cartridge form.

7. A liquid purification apparatus comprising the adsorbent-filled column according to any one of claims 1 to 5.

8. The liquid purification apparatus according to claim 7, having a filter for capturing fine particles.

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