JPS61204083A - Production of sterilized liquid - Google Patents

Abstract

PURPOSE:To improve a sterilizing rate by bringing an ion exchange membrane having the charge value selective permeability with ions of the same kind of charge into contact with a soln. in which bacteria exist, erecting electrodes to face each other with the ion exchange membrane in-between and passing the electric current above the threshold current density thereto. CONSTITUTION:The ion exchange membrane 1 having the charge value selective permeability with the ions of the same kind of charge is brought into contact with the soln. in which the bacteria exist. The electrodes 8, 8' are erected to face each other with the ion exchange membrane 1 in-between. The current above the threshold current density is passed thereto. The sterilizing rate is remarkably improved at the extremely low current density according to the above-mentioned method as compared to the conventional method. The economical and efficient production of the sterilized liquid is thus made possible from the soln. in which the bacteria exist.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a novel method for producing a sterile liquid using electrodialysis. Specifically, it is a method for efficiently and economically producing a sterile liquid without adding drugs or heat treatment.

[Technical Background] As a method of sterilizing impure water in which fungi are present, a method of adding chemicals such as chlorine and heavy metal salts has been generally known. However, in recent years, it has become a problem that chlorine sterilization of tap water produces methane, which is harmful to birds.Therefore, there has been a desire for a water sterilization method that does not involve the addition of chemicals such as chlorine. On the other hand, heat treatment by boiling or distillation is a method of sterilizing water that does not involve the addition of chemicals, but in these methods, if the water contains useful organic substances other than fungi, the effects of heat must be taken into account. Moreover, it is not suitable for industrial implementation because it requires a large amount of heat.

[Prior Art] In order to solve this problem, the present inventors have developed a solution that has been sterilized from an impure solution containing fungi (hereinafter also referred to as sterilized solution) without the addition of chemicals or heat treatment. As a method for producing
No. 9-30906) proposed a method of supplying water containing fungi to an electrodialysis tank used as an anion exchange membrane and a cation exchange membrane diaphragm and energizing it. In the above method, anion exchange membranes and cation exchange membranes are arranged alternately between electrodes to form a demineralization chamber and a concentration chamber, and water containing fungi, which is a liquid to be treated, is placed in the demineralization chamber side. A sterilizing solution is produced by supplying an electrolyte solution to the concentration chamber side.

[Problems to be Solved by the Invention] According to the above method, it is possible to sterilize a solution in which fungi are present. However, this method has a slow sterilization rate and requires operation at an abnormally high current density to obtain a sufficient sterilization rate, which has been a major obstacle in industrial implementation.

[Means for Solving the Problems] The present invention has been made in view of the above problems. A cell (also called a membrane) is arranged almost perpendicular to the current direction, and a solution containing fungi is supplied to the cell so as to be in contact with a selectively permeable ion exchange membrane. Provided is a method for producing a sterilizing solution that can significantly improve the sterilization speed at a low current density by passing a current higher than the current density.

The present invention relates to the production of a sterilizing solution, which is characterized in that a permselective ion exchange membrane is brought into contact with a solution containing fungi, and electrodes are opposed to each other with the ion exchange membrane in between to pass a current north of a critical current density. It's a method.

The solution containing the fungi targeted by the present invention is a polar solution such as water or alcohol that contains an electrolyte to the extent that electricity can be applied. The amount of electrolyte that can be energized varies depending on its type and cannot be further limited, but is generally 10 ppm or more. Furthermore, fungi include plankton, bacteria, molds, yeast, viruses, related microorganisms, pyrogens, etc., and the method of the present invention is effective against all of these fungi.

The permselective ion exchange membrane used in the present invention is one in which the transfer number within the membrane is different between ions of the same type of charge with different charge values.For example, in the case of a cation exchange membrane, the valence ion is sodium The selective permeability coefficient (PNa) between ions (Na+) and calcium ions (Ca), which are divalent ions, is 0.25NNaCI, 0.25
Using a solution of NCaCIz, temperature 25°C, current density IA
/dm 1 or more, preferably 0.7 or more,
In the case of anion exchange membranes, chlorine ions (−), which are negative valent ions,
The selective permeability coefficient (P"4) between CI-) and the divalent sulfate ion (SO=) is 0, 25 N N a C
0.0 when measured using a solution of l -0-25N N &2S 04 at a temperature of 25°C and a current density of IA/dn+.
5 or less, preferably 0.02 or less is suitably used. To give a more specific example of the above-mentioned permselective ion exchange membrane, (a) the cation (or anion) ion exchange membrane has a weakly acidic (or Weakly basic) layer having a positive (or negative) ion exchange group (b) resin layer having a negative (or positive) ion exchange group (c)
Resin j that has both an anion exchange group and a cation exchange group
- Re:) Resin 1- having a structure more dense than the above cation (or anion) ion exchange membrane; @(meq/g dry resin) is 2/3 or less, preferably 1/2 or less (including zero) of the above cation (or anion) ion exchange membrane (to) the resin layer (a) to ( Examples of composite membranes include laminations of at least one layer selected from resin layers having two or more of (4) that can be combined. Among the selectively permeable ion exchange membranes, layer (0), that is, a composite membrane in which an ion exchange membrane is laminated with a layer having an ion exchange group having an opposite sign to that of the ion exchange group possessed by the ion exchange membrane, has a low current. The effect of improving the speed of 11i bacteria in terms of density is the best and is particularly preferred. The permselective ion exchange membrane in the present invention also includes a so-called bipolar membrane in which a cation exchange membrane and an anion exchange membrane are laminated. The bipolar membrane referred to herein is not limited to a composite of an anion exchange membrane and a cation exchange membrane by laminating them together, but also includes a membrane in which the respective membranes are simply stacked on top of each other.

The method for manufacturing the composite membrane is not particularly limited, and any known method may be employed without any restriction. For example, as a typical manufacturing method, JP-A-Sho Fi2-81098
There is a method described in the publication.

Further, the cation (or anion) ion exchange membrane in the composite membrane is not particularly limited as long as it is a polymer film having a cation (or anion) ion exchange group, and may include hydrocarbon, fluorine-containing, condensed, Those produced by conventionally known methods, whether polymerized, homogeneous, or heterogeneous, can be used without particular limitation. Cation exchange groups include sulfonic acid groups, sulfuric ester groups, phosphoric acid groups, ethyl phosphate groups, sulfonic acid ester groups, carboxyl groups, sulfonic acid amides having a dissociable hydrogen atom, It is appropriately selected from acid amide groups such as carboxylic acid amide and phosphoric acid amide, phenolic hydroxyl groups, thiol groups, and the like. For example, when forming a layer having a weakly acidic cation exchange group in contrast to the ion exchange group inherent in the cation exchange membrane, the cation exchange group of the cation exchange membrane may be a sulfonic acid group, a sulfuric acid ester, etc. A strongly acidic or relatively strongly acidic cation exchange group such as a phosphoric acid group or a phosphoric acid group is selected.

Usage: Weakly acidic cation exchange groups include carboxyl groups, acid amide groups such as sulfonic acid amide, carboxylic acid amide, and phosphoric acid amide with dissociable hydrogen atoms, phenolic hydroxyl groups, thiol groups, and phosphorous acid groups. , phosphite group, etc. In addition, as anion exchange groups, -4,
Secondary, tertiary amines, quaternary ammonium bases, tertiary sulfonium bases, quaternary phosphonium bases, stibonium bases, arsonium bases, metal chelate compounds that are positively charged, such as cobaltidinium salts, neutral,
These include those that become positively charged in either acidic or basic atmospheres and can exchange anions. The above-mentioned cation exchange group may also be present in this layer having an anion exchange functional group, but out of all the ionic functional groups in this layer, 20 anion exchange functional groups are present. % or more is desirable.

Further, when a layer as described above is formed on an anion exchange membrane, the anion exchange group is generally a quaternary ammonium base, a quaternary phosphonium base, a stibonium base, an arsonium base, or the like. Examples of the weakly basic anion exchange group for the upper group anion exchange group include primary, secondary, and tertiary amino groups, groups containing metal chelates, and the like.

Furthermore, as the group having an opposite ion, all of the above examples of cation exchange groups can be applied.

In the present invention, an aspect of the cell configured using the permselective ion exchange membrane is such that a chamber is formed between the electrodes, and the permselective ion exchange membrane is arranged approximately perpendicularly to the current direction. If so, there are no particular limitations, and generally known structures of electrodialyzers are employed without particular limitations. For example, as shown in FIG. 1, there is a mode in which selectively permeable ion exchange membranes 1 and ordinary anion exchange membranes 2 are arranged alternately to form a desalting chamber 4 and a concentration chamber 3, as shown in FIG. As in, permselective ion exchange membrane LL! l - receiving force with an ordinary cation exchange membrane 5;
A third aspect of forming the concentration chamber 3 and the demineralization chamber 4 by arranging the
As shown in the figure, a typical embodiment is such that all the diaphragms are composed of 0-permselective ion exchange membranes 1 to form chambers 6.

In the embodiment shown in Fig. 3, the permselective ion exchange membrane may be of the same type and may be heated at °C, or an anion exchange membrane and a cation exchange membrane having permselectivity may be alternately arranged. You may. In addition, in the cell, the permselective ion exchange membrane l has the above-mentioned cation (or anion) ion exchange membrane
Located on the cathode (or anode) side of the stacked layers.
- It is preferable to provide it as follows.

In the present invention, the solution containing fungi may be supplied to the cell dialysis layer in any chamber as long as the solution can come into contact with the permselective ion exchange membrane 1 described above. 1st
In the figure, when a solution containing fungi is supplied to the demineralization chamber 4, the anions contained in the solution pass through the anion exchange membrane 2 and move to the concentration chamber 3, and the fungi are sterilized. .

In this case, an electrolyte solution may be supplied to the concentration chamber 3, or a solution containing fungi may also be supplied to the concentration chamber 3 for sterilization. In addition, in FIG. 2, the desalination chamber 4
When a solution containing fungi is supplied, the cations contained in the solution pass through the cation exchange membrane 5 and move to the concentration chamber 3, and the fungi are sterilized. In this case, as in the embodiment shown in FIG. 1, the electrolyte solution containing fungi can be supplied to the concentration chamber 3.

On the other hand, in the embodiment shown in Figure 3, when all the same types of membranes are used, even if a solution containing fungi is supplied to all the chambers,
Since ions permeate equally from each chamber, there is almost no change in the amount of electrolyte contained in the solution in the chambers other than the end portions, and there is also almost no change in PH.

Therefore, the cell to be used and the supply method may be determined from the above-mentioned aspects depending on the properties of the intended sterilizing liquid. Further, in the present invention, the sterilization liquid obtained from each chamber may be used separately or may be appropriately mixed.

Among the above embodiments, the second method (the embodiment shown in the figure in which a solution containing fungi is supplied to the chamber 6 of the cell) is the most recommended method in terms of the sterilization effect.

On the other hand, as a method for easily implementing the method of the present invention, the fourth
There is a method using the cell shown in the figure. The cell shown in FIG. 4 consists of a container 7 and a unit 1 in which a permselective ion exchange membrane 1 is supported between electrodes 8 and 8'. The production of a sterilizing solution using such a cell is carried out by placing a solution containing fungi in the container 7, inserting the unit 3- into the container 7, and passing a current higher than the critical current density between the electrodes for a certain period of time.

In the present invention, a cell to which a solution containing fungi is supplied has a current density greater than or equal to the critical current density, preferably 1% relative to the critical current density.
．． It is necessary to apply current at a current density of 1 to 10 times in order to exhibit a sterilization effect.

Further, since the current application time varies depending on the thickness of the cell chamber, the current density, the concentration of fungi, etc., an appropriate time to achieve the desired sterilization state may be determined by conducting experiments in advance.

[Operations and Effects] According to the method of the present invention, it is possible to significantly improve the sterilization rate with an extremely low current density compared to conventional methods. Therefore, a sterilizing solution can be economically and efficiently produced from a solution containing fungi.

In the method of the present invention, the mechanism by which the sterilization rate is dramatically improved at low current density is not clear, but it is thought that the surface activity of the selectively permeable ion exchange membrane works synergistically with the current density in some way. It will be done.

[Examples] Examples are shown below to further specifically explain the present invention, but the present invention is not limited to these Examples. In the Examples and Comparative Examples, the sterilization effect was determined by calculating the number of bacteria in the water before and after energization by the following method, and expressed as the viable rate after energization. To calculate the number of bacteria, dilute the culture solution and sample solution with sterile physiological saline, and add 0.05 to each dilution.
Spread m1 uniformly on the surface of the plate medium with a Conrage rod, 37
After culturing at ℃ for 24 hours, the resulting colonies were counted and measured.

Moreover, pyrodiene was measured by the following two types of measurements.

Method A) Measured using the pyrogenic substance test specified in the H Hydropharmacopoeia.

Method B) Measurement was performed using Pyrosade (trade name: Midori Juji Co., Ltd., Japan Standard Product Classification) as a reagent for detecting entodoxia.

The ion exchange membrane used in the examples and comparative examples was
Shown in the table.

Table 1 Example 1 A membrane with symbol C in Table 1 was used as a permselective ion exchange membrane.
A cell of the embodiment shown in FIG. 1 was constructed using five pairs of membranes with symbol B in Table 1 as anion exchange membranes. The permselective ion exchange membrane was arranged so that the cation exchange membrane faced the cathode side. Also, - the effective current direction product of the above cell is ldm2,
The thickness of each chamber was lcn.

Large+t! at a concentration that produces about 150 colonies in each of the desalination chamber and concentration chamber of the above cell! Water containing bacteria (0, IN
After passing the saline solution at a passing rate of BOcc/min, the treatment liquids in each chamber were mixed. At this time, current was applied to the cell at a current density that was a multiple of the limiting current density shown in Table 2.

The sterilization effect after the above treatment is also shown in Table 2.

Table 2 No. 1 is a comparative example.

Example 2 In Nos. and 4 of Example 1, the types of selectively permeable ion exchange membranes used were changed to those shown in Table 3.

Water containing fungi was treated in the same manner, except for λ. The results are shown in Table 3.

Table 3 Tree No. 3 is a comparative example.

Example 3 In No. 4 of Example 1, all of the diaphragms were replaced with the permselective ion exchange membranes shown in Table 4, and all the diaphragms were replaced with the same type of permselective ion exchange membranes as shown in Figure 3. Water containing fungi was treated in the same manner, except that: The results are shown in Table 4.

Table 4 Example 4 In Example 1 ONO04, the same method was used except that the arrangement of the permselective ion exchange membranes was changed to one in which C membranes and F membranes were listed alternately (current density 0). .48A/d-
carried out. As a result, the viable bacteria rate was 0%.

Example 5 Water containing fungi was treated in the same manner as in Example 3, except that pyrodiene-positive tap water was used as the fungi. The results are shown in Table 5. For reference, the results of untreated tap water are also shown in Table 5.

Table 5 Example 6 The same method as in Example 4 was carried out except that the liquid to be treated was replaced with seawater containing plankton and the current density was 1.5 times (7 A/dW?). As a result, the survival rate of plankton was zero.

[Brief explanation of the drawing]

FIG. 1, FIG. 2, FIG. 3, and FIG. 4 are schematic diagrams showing one embodiment of a cell used in the present invention. In the figure, 1 is a permselective ion exchange membrane, 2 is an anion exchange membrane, 3 is a concentration chamber, 4 is a desalination chamber, 5 is a cation exchange membrane, 6 is a chamber, 7 is a container, and 8.8' is a container. Electrode 1 indicates a unit, respectively.

Claims (1)

[Claims] (1) An ion exchange membrane that has charge-selective permeability to ions of the same charge is brought into contact with a solution containing fungi, and electrodes are opposed to each other with the ion exchange membrane in between to pass a current higher than the critical current density. Characteristic method for producing sterile liquid.