JPH0899088A - Production of electrolytic ionic water - Google Patents

Abstract

PURPOSE: To produce electrolytic ionic water by using a diaphragm suitable for the production of electrolytic ionic water, more precisely, a diaphragm having sufficient hydrophilicity and having oxidation resistance, alkali resistance and long-term stable heat resistance. CONSTITUTION: A cathode chamber and an anode chamber are partitioned by a diaphragm and DC voltage is applied across the electrodes installed in both chambers to produce electrolytic ionic water. In this method, as the diaphragm, a hydrophilic porous fluoroplastic film having infrared absorption resulting from a C-O bond in a wave number of 1000-1200cm<-1> and characterized by that an F/C value due to an X-ray photoelectric spectral method is 0.1-1.5 and an O/C value is 0.1-1.0 is used.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing electrolytic ionized water by using a diaphragm suitable for producing electrolytic ionized water, and more specifically, it has sufficient hydrophilicity, acid resistance, alkali resistance, and long resistance. The present invention relates to a method for producing electrolyzed ionic water using a diaphragm having stable heat resistance for a period of time.

[0002]

BACKGROUND OF THE INVENTION It is generally recognized that drinking water containing alkaline ions is beneficial for health and acidic water has cosmetic effects. Therefore, a device for producing electrolytic ionized water for household and business use is commercially available. An apparatus for producing alkaline drinking water by electrodialysis is disclosed in Japanese Patent Laid-Open No. 48-42562.
JP-A-59-92090 and the like describe the structure. Raw water is put in the anode chamber and the cathode chamber of the electrolytic cell, and a DC voltage is applied to the electrodes of both electrode chambers for a predetermined time to perform dialysis. , A so-called batch type for producing alkaline drinking water in the cathode chamber, or connecting the raw water supply port to both electrode chambers to a water tap,
A continuous type has been proposed in which raw water is dialyzed while being supplied, and drinking water is continuously taken from the discharge port of the cathode chamber. Conventionally, a bisque plate, an ion-permeable porous membrane such as polyethylene, polypropylene, or acetate has been used as a diaphragm that separates the raw water from the generated alkaline ionized water or acidic water. In the case of a hydrophobic diaphragm, it is hydrophilized by coating a hydrophilic monomer or polymer and crosslinking.

[0003]

However, chlorine remaining in tap water used as raw water becomes active chlorine or chlorine gas during electrolysis, which adversely affects the hydrophilic coating layer of the diaphragm or the diaphragm itself. There is a problem that the hydrophilic property is deteriorated and the diaphragm is weakened.

[0004]

SUMMARY OF THE INVENTION The present invention has been made to solve the problems of the prior art. As a diaphragm for the production of electrolyzed ionic water, a specific hydrophilic porous material that has been subjected to photochemical treatment is used. Porous fluororesin film, that is, a porous fluororesin film obtained by introducing a hydrophilic group by a photochemical reaction using a specific compound described below on the surface of the internal tissue as well as the surface of the porous fluororesin film Provided is a method for producing electrolyzed ionized water, which imparts sufficient hydrophilicity to a film, is stable to chlorine and its derivatives in tap water, and can withstand use at high temperatures for a long time.

That is, the present invention provides a method for producing electrolytic ionic water containing alkaline drinking water and acidic water by partitioning the cathode chamber and the anode chamber with a diaphragm and applying a DC voltage to the electrodes provided in the bipolar chamber. As the wave number 1000-1200c
m ⁻¹ has an infrared absorption derived from a C—O bond, and has an F / C value of 0.1 to 1.5 and an O / C by X-ray photoelectron spectroscopy.
The present invention relates to a method for producing electrolyzed ionized water, which comprises using a hydrophilic porous fluororesin film having a value of 0.1 to 1.0, and the hydrophilic porous fluororesin film described above is a porous fluororesin film. It is preferable to use a film obtained by irradiating with ultraviolet rays in a state where an atom having a binding energy with a fluorine atom of 539 kJ / mol or more and a compound having a hydrophilic group are in contact with each other.

The porous fluororesin film in the present invention is made of polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVdF), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PF).
A), a hydrophobic film made of tetrafluoroethylene-hexafluoropropylene copolymer (FEP), tetrafluoroethylene-ethylene copolymer (ETFE), polychlorotrifluoroethylene (CTFE), etc., and particularly chemical resistance In terms of heat resistance and the like, PTFE is preferable, and either a baked product or an unbaked product can be used. Also 0.01-2
A film having a pore size of 0 μm, particularly 0.05 to 5 μm is preferably used. The porous fluororesin film can be obtained by various methods. For example, PTFE films are disclosed in Japanese Patent Publication No. 58-25332 and Japanese Patent Publication No. 51-18.
It can be obtained by a stretching method described in Japanese Patent Publication No. 991, Japanese Patent Publication No. 42-13560, etc., or a method using a foaming agent described in Japanese Patent Publication No. 42-4974, etc.

These porous fluororesin films are essentially C except for PFA before the photochemical treatment according to the present invention.
No infrared absorption due to —O bond was observed, while XPS
Approximate F / C and O / C values by the method are PT
FE (2.0, 0), PVdF (1.0, 0), PFA (2.0,
0.2 or less), FEP (2.0, 0), ETFE (1.0, 0),
It has CTFE (1.5,0). The photochemical treatment preferable in the present invention is such that the above porous fluororesin film has a binding energy of 539 kJ / mol with a fluorine atom.
Ultraviolet rays are radiated in a state where the above-mentioned atom and the compound having a hydrophilic group are in contact with each other, and C is applied at a wave number of 1000 to 1200 cm ^-1 .
Has infrared absorption derived from —O bond, and has F / C value of 0.1 to 1.5 and O / C value of 0.1 to 1.0 by XPS method.
Of the hydrophilic porous fluororesin film.
Processing operations are usually depending on the compound used, the ultraviolet rays having a wavelength of 150~270nm 6J / cm ² or more, and it is preferably irradiated at an energy intensity of 6~500J / cm ^2.

The compound used in the present invention is a compound having an atom having a binding energy with a fluorine atom of 539 kJ / mol or more and a hydrophilic group, and the electronegativity of the atom is 2.5.
Preferably there are: These compounds include
Aluminum (bonding energy with fluorine atom: 671
kJ / mol, electronegativity: 1.5), boron (745
kJ / mol, 2.0), calcium (560 kJ / m)
ol, 1.0), barium (581 kJ / mol, 1.
2), having an atomic group such as lithium (580 kJ / mol, 1.0) and hydrogen (566 kJ / mol, 2.1) and a hydrophilic group, for example, aluminum hydroxide, boric acid, ammonium borate, lithium hydroxide, water. Compounds such as calcium oxide, barium hydroxide, aluminum ethoxide, formic acid and acetic acid can be used. In the present invention, an aqueous solution of these compounds is preferably used, and an aqueous solution of an aluminum compound, a boron compound or a lithium compound having a hydrophilic group is particularly preferable. Further, an alkali salt such as sodium hydroxide or potassium hydroxide may be added to increase the solubility of the solute.

In the present invention, the compound is irradiated with ultraviolet rays in a state of being brought into contact with the porous fluororesin film, but it may be impregnated with an aqueous solution of the compound so as to penetrate the surface of the porous internal tissue. Good contact. In addition, since the porous fluororesin film itself is hydrophobic, plasma (H ₂ , O ₂ , Ar, CO ₂ , A) is used as a pretreatment for performing the above impregnation and coating steps more smoothly.
Ir, H ₂ O, etc.), an excimer laser, a low-pressure mercury lamp, an electron beam, radiation, an excimer lamp, or the like may be applied to make the surface of the porous fluororesin film hydrophilic.

As the ultraviolet light source, the C—F bond (53
9 kJ / mol) may be cut with one photon or with a small amount of two photons, and the photon energy for cutting the C—F bond preferably has a wavelength of 270 nm or less. However, if the wavelength is too short, light is strongly absorbed by the fluororesin film, so that sufficient energy for causing a photochemical reaction is difficult to reach in the film thickness direction.
Therefore, it is preferable that the ultraviolet rays have a wavelength of 150 to 270 nm. As the ultraviolet light source, a low-pressure mercury lamp, a high-pressure mercury lamp, a YAG laser (fourth harmonic), a metal halide lamp, an excimer lamp, or the like can be used. preferable.

By irradiating ultraviolet rays from such a light source, the CF bond (539
cJ / mol) is cut. At this time, by allowing an atom having a bond energy with the fluorine atom of C—F bond (539 kJ / mol) or more to exist, the cleaved fluorine atom bonds with the atom and is trapped. The electronegativity of the fluorine atom is as large as 4.0, so that the presence of atoms smaller than the carbon atom (electronegativity: 2.5) causes CF
It is possible to prevent reconnection between them. The bond energy between the atom and the fluorine atom is higher than that of the C—F bond, so that the bond is not easily broken again. Therefore, a part of the fluorine atoms of the porous fluororesin film can be replaced with the hydrophilic group.

By such hydrophilic treatment, C—O such as C—OH, C—COOH, and C—O—C is attached to the main chain, side chain or terminal of the polymer of the porous fluororesin on the surface of the separator pores.
Since a hydrophilic group having a bond is introduced, it is hydrophilic and has excellent alkali resistance and acid resistance. Here, the term "pore surface" means a surface that constitutes the porosity of the separator and an internal tissue surface, and the portion that is hydrophilized by the above hydrophilization treatment is not only the separator surface but also the internal tissue surface. It is characterized by being formed in.

The hydrophilic porous fluororesin film obtained by the above photochemical treatment has a wave number of 1 by infrared absorption method.
000 to 1200 cm ⁻¹ has an infrared absorption derived from a C—O bond, and has an F / C value of 0.1 to 10 in the XPS method.
The value of 1.5 and the O / C value are in the range of 0.1 to 1.0. F / C
If the value is smaller than 0.1 and the O / C value is larger than 1.0, the original properties of the fluororesin are lost, and if the F / C value is larger than 1.5 and the O / C value is smaller than 0.1, the hydrophilicity tends to be poor. Appears.

In the method for producing electrolytic ionized water of the present invention, the cathode chamber and the anode chamber are partitioned by a diaphragm, and a DC voltage is applied to the electrodes provided in both electrode chambers to produce electrolytic ionized water containing alkaline drinking water and acidic water. In the apparatus described above, the hydrophilic fluoropolymer film is used as a diaphragm to produce electrolytically ionized water.

[0015]

In the present invention, as a diaphragm for the production of electrolytic ionized water, C--O at a wave number of 1000 to 1200 cm ^-1 is used.
It has an infrared absorption derived from a bond and has an F / C value of 0.1 to 1.5 and an O / C value of 0.1 to X determined by X-ray photoelectron spectroscopy.
A hydrophilic porous fluororesin film of 1.0 is used, and the preferred production method is a state in which a compound having a hydrophilic group and an atom having a binding energy with a fluorine atom of 539 kJ / mol or more is brought into contact with the porous fluororesin film. Obtained by irradiating ultraviolet rays. Therefore, not only the surface of the porous fluororesin film having strong hydrophobicity, but also the surface of the internal tissue has been subjected to a hydrophilic treatment, which can sufficiently absorb and retain the electrolytic solution, and also has oxidation resistance and alkali resistance, and even at high temperatures. Since it is stable and can maintain the performance for a long period of time, it is possible to produce electrolytic ionized water having good quality and stable performance.

[0016]

EXAMPLE FIG. 1 is a flow sheet showing an example of a method for producing electrolyzed ionized water according to the present invention. A cathode chamber and an anode chamber of an electrolytic cell 7 are partitioned from each other by a diaphragm 3 to form a cathode chamber and an anode chamber. The pH sensor 8 is provided on the cathode 1 side. Tap water 4 from city water tap is a purification filter 5
A predetermined amount is put into the cathode chamber and the anode chamber through (for example, a microfiltration membrane, an activated carbon layer, etc.), and if necessary, a health-effective drug 6 (for example, calcium lactate, calcium sulfite,
Piping can be provided to add (calcium chloride, potassium chloride, etc.) to the anode chamber. In such an apparatus, a DC voltage is applied to the cathode 1 and the anode 2 to perform electrolysis. The pH of the alkaline ionized water produced by electrolysis is measured by the pH sensor 8 and the voltage between both electrodes is adjusted to a predetermined pH. And adjust the energization time. After this operation, alkaline ionized water 9 is taken out from the cathode chamber and acidic water 10 is taken out from the anode chamber, respectively. Although the above flow sheet shows a batch system, a continuous system in which a part of the alkaline ionized water 9 taken out from the cathode chamber is circulated to the cathode chamber by a circulation pump can also be used.

Example 1 Polytetrafluoroethylene (PTFE) porous film (manufactured by Nitto Denko KK, trade name NTF1122, nominal pore size of 0.
2 μm) was successively dipped in methanol and water for 10 minutes each, and further dipped in a 4.1 wt% boric acid aqueous solution for 10 minutes to impregnate the pores with the boric acid aqueous solution. This film has a low pressure mercury lamp with an output of 650 W (Oak Co., Ltd .; VU
After irradiation with V-65B-22-21 (wavelength: 185 nm, 254 nm) for 60 seconds, the membrane was washed with pure water and air-dried to obtain a diaphragm useful for producing electrolytic ionized water. When analyzed by XPS method, the above porous film before photochemical treatment had F / C =
Although 2.0 and O / C = 0.01, the diaphragm after treatment had F / C = 0.28 and O / C = 0.19, and the ratio of F decreased and O increased. Was confirmed. Also,
Waveform analysis revealed that -CF ₂ -bonding (292e
If the number of C atoms in V) is 100, then —C—O— bond (2
86 eV) is 80, and -C = O bond (288 eV) is 16
It was confirmed that a hydrophilic group was present. Prior to treatment, those functional groups were absent. In addition, from the infrared absorption spectrum of the treated diaphragm, the wave number of 1000-
Infrared absorption derived from the C—O bond was observed at 1200 cm ⁻¹ . This diaphragm is a PTFE porous film that is originally hydrophobic and has been hydrophilized by the photochemical treatment described above. There is almost no dimensional change even after being immersed in hot water at 90 ° C for 7 days, and it is sufficiently hydrophilic. She maintained her sex. Using this diaphragm in the apparatus of FIG. 1, alkaline ionized water having a pH of 9 was produced. Compared to the initial water production capacity (alkaline ionized water production amount per unit time), the water production capacity after 5 m ³ water production decreased by 2%, but when the membrane was taken out and examined, there was no change in hydrophilicity. It was

Comparative Example As a diaphragm, a hydrophilic polymer (polyvinylpyrrolidone)
Alkaline ionized water was made in the same manner as in Example 1 by using a polypropylene porous membrane coated with and subjected to a hydrophilic treatment. After 5 m ³ of alkaline ionized water having a pH of 9 was prepared, the water production capacity was reduced by about 20% compared to the initial stage, and when the diaphragm was taken out and examined, about 10% of the area was hydrophobized.

Example 2 4% by weight of aluminum hydroxide was used instead of the boric acid aqueous solution.
A diaphragm for producing electrolytic ionized water was obtained in the same manner as in Example 1 except that an aqueous solution containing 10% by weight of sodium hydroxide was used. Table 1 shows the results of the same evaluation of the diaphragm and the water production test as in Example 1.

Example 3 A diaphragm for producing electrolyzed ionized water was obtained in the same manner as in Example 1 except that a 10 wt% formic acid aqueous solution was used instead of the boric acid aqueous solution. Table 1 shows the results of the same evaluation of the diaphragm and the water production test as in Example 1.

Example 4 A diaphragm for producing electrolytic ionized water was obtained in the same manner as in Example 1 except that a 20 wt% lithium hydroxide aqueous solution was used instead of the boric acid aqueous solution. Table 1 shows the results of the same evaluation of the diaphragm and the water production test as in Example 1.

[0022]

[Table 1]

[0023]

[Brief description of drawings]

FIG. 1 is a flow sheet showing an example of producing electrolytic ionized water in the present invention. 1: Cathode 2: Anode 3: Diaphragm 4: Tap water 5: Purification filter 7: Electrolyzer 9: Alkaline ionized water 10: Acidic water

Claims (4)

[Claims] 1. A method for producing electrolytic ionized water containing alkaline drinking water and acidic water by partitioning a cathode chamber and an anode chamber with a diaphragm, and applying a DC voltage to electrodes provided in both electrode chambers, wherein the diaphragm has a wave number. C-O at 1000 to 1200 cm ^-1
It has an infrared absorption derived from a bond and has an F / C value of 0.1 to 1.5 and an O / C value of 0.1 to X determined by X-ray photoelectron spectroscopy.
Method for producing electrolyzed ionized water characterized by using a hydrophilic porous fluororesin film of 1.0 2. CO at a wave number of 1000 to 1200 cm ^-1
It has an infrared absorption derived from a bond and has an F / C value of 0.1 to 1.5 and an O / C value of 0.1 to X determined by X-ray photoelectron spectroscopy.
A hydrophilic porous fluororesin film of 1.0 has a binding energy of 53 with a fluorine atom in the porous fluororesin film.
The method for producing electrolyzed ionized water according to claim 1, which is obtained by irradiating with ultraviolet light in a state where a compound having a hydrophilic group and an atom of 9 kJ / mol or more are in contact with each other. 3. The method for producing electrolytic ionized water according to claim 2, wherein the compound is an aluminum compound, a boron compound, a lithium compound, or a hydrogen compound. 4. The method for producing electrolyzed ionized water according to claim 2, wherein a light source having a wavelength of 150 to 270 nm as ultraviolet rays is used.