JP2013237944A - Cross-linked catalase immobilized fiber and ultrapure water producing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide new hydrogen peroxide decomposition means that can be inexpensively obtained, and to provide an ultrapure water producing apparatus provide with the new hydrogen peroxide decomposition means.SOLUTION: The ultrapure water producing apparatus comprises: a pretreatment device (A) of raw water; a primary purified water producing device (B); a secondary purified water producing device (C) including a low-pressure ultraviolet oxidation device; and further a hydrogen peroxide decomposition device arranged after the low-pressure ultraviolet oxidation device, and uses a cross-linked catalase immobilized fiber as a decomposition catalyst in the hydrogen peroxide decomposition device.

Description

  The present invention relates to a crosslinked catalase-immobilized fiber and an ultrapure water production apparatus.

  In the field of electronic industries such as semiconductors, pure water such as ultrapure water from which organic substances, ionic components, fine particles, bacteria, and the like are highly removed is used as cleaning water.

  Conventionally, many proposals have been made as ultrapure water production apparatuses, but there are those equipped with hydrogen peroxide decomposition means. Such hydrogen peroxide is generated due to hydrogen peroxide as an oxidizing agent added to the water to be treated for removal of organic components or ultraviolet irradiation of the oxidative decomposition means.

  As a means for decomposing hydrogen peroxide, an anion exchange resin carrying a platinum group metal catalyst such as palladium is used (Patent Documents 1 and 2). However, platinum group metal catalysts are expensive. In addition, as a means for decomposing hydrogen peroxide, there is a decomposition method using activated carbon. However, in the case of production of ultrapure water, impurities are eluted from the activated carbon, so that it is often not suitable for use.

JP 2011-167633 A JP 2011-218248 A

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a novel hydrogen peroxide decomposition means that can be obtained at low cost. Another object of the present invention is to provide an ultrapure water production apparatus provided with a novel hydrogen peroxide decomposition means.

  That is, the first gist of the present invention resides in a cross-linked catalase-immobilized fiber, and the second gist of the present invention is a raw water pretreatment device (A), a primary pure water production device (B), and a low-pressure ultraviolet oxidation device. A secondary pure water production apparatus (C) including a hydrogen peroxide decomposition apparatus after the low-pressure ultraviolet oxidation apparatus, and a crosslinked catalase-immobilized fiber as a decomposition catalyst for the hydrogen peroxide decomposition apparatus. It exists in the ultrapure water production apparatus characterized by using.

  According to the present invention, the above-described problems are achieved.

FIG. 1 is a system diagram showing an example of an ultrapure water production apparatus used in the present invention. FIG. 2 is a cross-sectional explanatory view of an example of an enzymatic decomposition apparatus for hydrogen peroxide.

  Hereinafter, the present invention will be described in detail.

<Cross-linked catalase immobilized fiber>

  Examples of the fiber in the cross-linked catalase-immobilized fiber of the present invention include polyolefin (polyethylene, polypropylene, etc.), nylon, polytetrafluoroethylene and the like, and nylon fiber is preferable from the viewpoint of strength and cost. Since the catalase fixing carrier is a fiber, the catalase is fixed on the surface of the carrier. Therefore, the problem caused when the carrier is a porous hollow fiber membrane, that is, the problem that the decomposition rate of hydrogen peroxide is influenced by the internal diffusion of the liquid to be treated does not occur.

  The crosslinked catalase-immobilized fiber of the present invention is, for example, a method in which catalase is immobilized on a fiber in which an anion exchange functional group is immobilized by graft polymerization (anion exchange graft chain-equipped fiber), and then catalase is further crosslinked with transglutaminase. Can be obtained. This will be described in detail below.

  First, in accordance with a radiation graft polymerization method, the fiber is irradiated with, for example, an electron beam to form radicals, and then an anion exchange graft chain is introduced. Although it does not restrict | limit especially as a monomer used for introduction | transduction of an anion exchange graft chain, For example, (alpha) derived | led-out from C1-C10 aliphatic alcohol which has an amino group, and (alpha), (beta) -unsaturated carboxylic acid. , Β-unsaturated carboxylic esters, ie, N, N-diethylaminoethyl acrylate, N, N-diethylaminoethyl methacrylate, N, N-dimethylaminoethyl acrylate, N, N-dimethylaminoethyl methacrylate, N-methyl-N -Ethylaminoethyl acrylate, N-methyl-N-ethylaminoethyl methacrylate and the like. Among these, N, N-dimethylaminoethyl methacrylate (DMAEMA) is preferable.

  Examples of radiation include α, β, γ rays, and electron beams, and any of them can be used, but electron beams are suitable. In addition, after irradiation, there are pre-irradiation methods in which the generated radicals are brought into contact with the monomer as a starting point, and simultaneous irradiation methods in which radiation is irradiated in a monomer solution, but stable production becomes possible. Is a pre-irradiation method. The irradiation dose is usually 50 to 300 kGy. The polymerization solvent is not particularly limited, but water is usually sufficient. The monomer concentration is usually 1 to 10 (v / v)%, the polymerization temperature is usually 25 to 60 ° C., and the polymerization time is usually 1 to 30 hours. The graft ratio represented by the following formula (1) is usually 15 to 50%, and the graft group density represented by the following formula (2) is 0.5 to 5 (mmol / g-dry). is there.

[Equation 1]
Graft rate [(w / w)%] = (weight of graft chain imparted) / (fiber weight before polymerization) × 100 (1)

[Equation 2]
Graft group density [(mmol / g-dry)] = (number of moles of graft group imparted) / (weight of fiber loaded with anion exchange graft chain) Formula (2)

  Next, catalase is adsorbed on the anion exchange graft chain-loaded fiber and fixed. In this case, catalase is used as a solution by dissolving in a suitable buffer, for example, 20 mM Tris-HCl buffer having a pH of 7.0. The adsorption method is not particularly limited, but if a column system in which an anion exchange graft chain-loaded fiber cut to an appropriate length is packed in a column and a catalase solution is supplied from the top of the column is adopted, catalase in the effluent of the column is used. By tracking the concentration, it is possible to easily grasp the adsorption state of catalase. The concentration of the catalase solution supplied from the top of the column is usually 0.01 to 0.5 (w / v)%.

  The catalase is then cross-linked by an enzymatic cross-linking agent such as transglutaminase. The concentration of the enzymatic crosslinker solution is usually 0.001 to 0.1 (w / v)%. It is easy to carry out the cross-linking reaction following the catalase adsorption operation by the above-mentioned column system, and the cross-linking reaction is carried out by circulating the enzymatic cross-linking agent solution through the column using an appropriate pump. The crosslinking temperature is usually 25 to 60 ° C., and the crosslinking time is usually 1 to 10 hours.

  Thereafter, uncrosslinked catalase is eluted and removed. For elution, for example, a 0.1-1M NaCl aqueous solution can be used. This operation is easy to carry out by adopting the above column system and supplying an aqueous NaCl solution from the upper part of the column. By tracking the concentration of catalase in the effluent of the column, it is possible to easily grasp the elution and removal status of uncrosslinked catalase.

  The cross-linking fixation capacity and the cross-linking rate of catalase can be calculated by the following formulas (3) and (4).

[Equation 3]
Catalase cross-linking fixation capacity (mmol / mL-bed) = [(catalase adsorption amount) − (catalase washing and elution amount)] / (column packing volume of anion-exchange graft chain-loaded fiber) Formula (3)

[Equation 4]
Cross-linking rate (%) = [(catalase adsorption amount) − (catalase washing and elution amount)] / (catalase adsorption amount) × 100 ·· Formula (4)

  The crosslinked catalase-immobilized fiber of the present invention can be used in a method for decomposing hydrogen peroxide present in an aqueous liquid. Examples of the aqueous liquid include a liquid containing hydrogen peroxide derived from a production process of a polymer or an organic compound by a polymerization reaction or an oxidation reaction using hydrogen peroxide, and a wastewater containing hydrogen peroxide. . Furthermore, there may be mentioned semiconductor manufacturing process wastewater, fiber bleaching process wastewater, dye decolorization process wastewater, pulp bleaching process wastewater, or wastewater that has been sterilized, deodorized, bleached or decolorized with hydrogen peroxide. A preferred use mode of the cross-linked catalase-immobilized fiber of the present invention is an apparatus for producing high-purity water such as a wastewater treatment apparatus containing hydrogen peroxide used for the purpose of sterilization in a food production process or a pure water production apparatus. As a decomposition catalyst in a hydrogen peroxide decomposition apparatus. A particularly preferable usage mode is a usage mode in the ultrapure water production apparatus of the present invention described below.

<Ultrapure water production equipment>

  As shown in FIG. 1, the basic configuration of the ultrapure water production apparatus of the present invention is a secondary pure water production system including a raw water pretreatment device (A), a primary pure water production device (B), and a low-pressure ultraviolet oxidation device. It consists of device (C).

  The raw water pretreatment device (A) is configured by sequentially providing a turbidity UF device (1) and an activated carbon tower (2). The activated carbon tower (2) is an optional facility and can be omitted depending on the situation.

  The primary pure water production apparatus (B) is configured by sequentially providing an RO membrane apparatus (3) and an electric regeneration type ion exchange apparatus (4). It is also possible to use a RO membrane device instead of the electric regenerative ion exchange device (4) and arrange a two-stage membrane separation device. The primary pure water obtained by the primary pure water production apparatus (B) is stored in the primary pure water tank (5).

  The secondary pure water production apparatus (C) includes a low-pressure ultraviolet oxidation apparatus (6), a hydrogen peroxide decomposition apparatus (7), a degassing apparatus (8), a mixed bed ion exchange apparatus (9), and a UF membrane apparatus (10). ) In sequence. The low-pressure ultraviolet oxidizer (6) has a function of ionizing or decomposing TOC. The peroxide water generated at this time is decomposed into oxygen and water by the hydrogen peroxide decomposition device (7), and the oxygen is removed by the deaeration device (7).

  In addition, each component of said pre-processing apparatus (A), primary pure water manufacturing apparatus (B), and secondary pure water manufacturing apparatus (C) is well-known in the field | area of an ultrapure water manufacturing apparatus, For example, reference can be made to the description of JP-A-6-86997.

  The ultrapure water production apparatus of the present invention is characterized in that a crosslinked catalase-immobilized fiber is used as a decomposition catalyst for the hydrogen peroxide decomposition apparatus (7).

  In the hydrogen peroxide enzyme decomposition apparatus (7) illustrated in FIG. 2, a cross-linked catalase-immobilized fiber (15) is accommodated inside, and a sprinkling pipe (12) connected to the treated water inflow pipe (11) is disposed at the top. A water collecting pipe (14) arranged and connected to the treated water outflow pipe (13) has an apparatus structure in which the water collecting pipe (14) is arranged at the lower part. Water to be treated containing hydrogen peroxide is supplied in a pressurized state from the water passage hole of the water spray pipe (12), contacts the cross-linked catalase-immobilized fiber (15) in descending flow, and passes through the slit of the water collecting pipe (14). Is taken out through. Then, hydrogen peroxide in the water to be treated is decomposed into oxygen and water by catalase.

  EXAMPLES Hereinafter, although an Example demonstrates this invention still in detail, this invention is not limited to a following example, unless the summary is exceeded.

Example 1:
<Manufacture of cross-linked catalase-immobilized fiber>
In a nitrogen atmosphere, a surface of 1.0 g of commercially available nylon-6 (Ny) fiber having a thickness of 25 μm was irradiated with a 200 kGy electron beam, and then immersed in a DMAEMA aqueous solution having a concentration of 3 (v / v)% at 40 ° C. for 24 hours. A graft chain was imparted to the Ny fiber to obtain an anion exchange graft chain-loaded fiber. The graft ratio of the formula (1) was 33%.

Next, 0.11 g of the above-mentioned anion exchange graft chain-loaded fiber is cut every 1 cm, packed into a column having an inner diameter of 5.5 mm, and a catalase solution under a condition of SV: 20 h ⁻¹ by a syringe pump from the top of the column. (1.0 g / L, Tris-HCl buffer pH 7.0) was supplied, and catalase was adsorbed on the anion exchange graft chain-loaded fiber. At this time, the catalase concentration in the solution flowing out from the column was traced, and the catalase adsorption operation was terminated when the catalase outflow concentration reached 90% of the supply concentration.

Next, a peristaltic pump is used in place of the above syringe pump, and a transglutaminase (TG) solution (0.04 wt%, Tris-HCl buffer pH 7.0) is supplied from the top of the column under the condition of SV: 30h ^−1. Then, the mixture was circulated for 2 hours, the enzyme was cross-linked between catalase and fixed to the graft chain.

Next, a syringe pump is used in place of the peristaltic pump, and a 1.0 M NaCl aqueous solution is supplied from the top of the column under the condition of SV: 20 h ⁻¹ to elute and remove uncrosslinked catalase to fix the cross-linked catalase. A modified fiber was obtained. The cross-linking fixation capacity of the catalase of the formula (3) was 18 (mg / mL-bed), and the cross-linking ratio of the formula (4) was 69%.

<Evaluation of hydrogen peroxide decomposition performance of cross-linked catalase immobilized fiber>
After the elution and removal operation of uncrosslinked catalase in the above production, a hydrogen peroxide aqueous solution having a concentration of 170 (μg-H ₂ O ₂ / L) is supplied from a syringe pump, and the hydrogen peroxide is decomposed by the crosslinked catalase-immobilized fiber. A test was conducted. The test was conducted by changing the supply rate (SV) of the aqueous hydrogen peroxide solution. When the SV was 50 to 200 h ⁻¹ , the decomposition rate of hydrogen peroxide was 100% without depending on the SV. Further, as a result of changing the concentration of the aqueous hydrogen peroxide solution and performing the same evaluation as described above, the decomposition rate at the concentration 510 (μg-H ₂ O ₂ / L) does not depend on the SV in the SV range. The decomposition rate at a concentration of 1050 (μg-H ₂ O ₂ / L) was 96% independent of SV.

Example 2 and Comparative Example 1:
The ultrapure water production apparatus with a treated water amount of 3 m ³ / h shown in FIGS. 1 and 2 was used. As the cross-linked catalase-immobilized fiber (15) of the hydrogen peroxide enzymatic decomposition apparatus shown in FIG. 2, one obtained by the same method as in Example 1 was cut every 1 cm. As raw water, Yokohama city water was used, and the water flow SV of the treated water with respect to the cross-linked catalase-immobilized fiber (15) was 200h- ¹ . Table 1 shows the analysis results of the hydrogen peroxide concentration of the treated water and the water in the enzyme decomposition apparatus. In addition, for comparison, the results obtained in the same manner as described above except that the enzyme decomposing apparatus is not used are also shown.

A: Pretreatment device B: Primary pure water production device C: Secondary pure water production device 1: Turbidity UF device 2: Activated carbon tower 3: RO membrane device 4: Electric regenerative ion exchange device 5: Primary pure water tank 6: Low-pressure ultraviolet oxidation device 7: Hydrogen peroxide decomposition device 8: Deaeration device 9: Mixed bed type ion exchange device 10: UF membrane device 11: treated water inflow pipe 12: sprinkling pipe 13: treated water outflow pipe 14: collecting pipe 15 : Cross-linked catalase immobilized fiber

Claims (4)

  Cross-linked catalase immobilized fiber.   The crosslinked catalase-immobilized fiber according to claim 1, which is obtained by immobilizing catalase on a fiber in which an anion exchange functional group is immobilized by graft polymerization, and further crosslinking catalase with transglutaminase.   The cross-linked catalase-immobilized fiber according to claim 1 or 2, wherein the cross-linked catalase-immobilized fiber is a nylon fiber.   A raw water pre-treatment device (A), a primary pure water production device (B), and a secondary pure water production device (C) including a low-pressure ultraviolet oxidation device, and a hydrogen peroxide decomposition device after the low-pressure ultraviolet oxidation device An ultrapure water production apparatus comprising a cross-linked catalase-immobilized fiber as a decomposition catalyst for a hydrogen peroxide decomposition apparatus.

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