JPS5929005A - Dehydrating method of gel or pasty matter - Google Patents

Abstract

PURPOSE:To dehydrate efficiently without giving an influence of electrochemical reaction, by performing an electroosmosis while adjusting a pH of hydrous gel or pasty matter which is in contacting with an electrolyte at the side of an anode or a cathode through a diaphragm. CONSTITUTION:At the side of an anode or a cathode, an electrolyte is brought into contact with hydrous gel or pasty matter through a diaphragm, and the dehydration of them is performed by an electroosmosis by adjusting the pH of the gel or the pasty matter while supplying electric power at least. Thus the influence affecting directly or indirectly on an object to be dehydrated such as the gel, which is caused from an electrochemical reaction generating at an electrode, is restricted to the minimum by said method thereby the object is efficiently dehydrated. For achieving said pH control, methods of controlling the pH of an electrolyte at the side of an anode and/or a cathode, or using a buffer solution as an electrolyte, or further a method of incorporating ion-exchange resin in the electrolyte, etc. are respectively effective.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for dehydrating hydrogels or pastes using electroosmotic phenomena, and more specifically, to a method for dehydrating hydrogels or pastes efficiently without causing chemical changes to the hydrogels or pastes. This invention relates to a new dehydration method using electroosmotic dehydration.

The dehydration method by electroosmosis is a long-known technology, but it is not practical due to the large amount of electricity it uses and the chemical action of the electrodes, so it is an effective method when used in conjunction with pressurization or suction p. It was only used as a.

As a method for improving the above-mentioned drawbacks of conventionally known electroosmotic dehydration methods, the applicant has already proposed a method in which the electrodes in electroosmosis are separated by an ion exchange membrane to influence the electrode reaction on the object to be dehydrated. A method for efficiently dehydrating using the electroosmotic properties of ion exchange membranes.
(Japanese Patent Application No. 52-143301), by using a membrane in addition to the membrane separating the bipolar chambers and providing a water drainage chamber separated by membranes on both sides, water can be efficiently removed from the gel or paste. Method for extracting ions (JP-A-54-14138
No. 7) Furthermore, a method for efficiently dehydrating the gel by dividing the gel into multiple pieces using a membrane other than the membrane separating the polar chambers (
JP-A-54-153782) was proposed.

The above method has significantly improved efficiency and effects on electrode chemistry, etc., compared to conventionally known methods;
Effect of acid or alkali generated in the electrode chamber on the object to be dehydrated (chemical action).

Contamination), there was room for improvement.

An object of the present invention is to efficiently dehydrate an object to be dehydrated in a dehydration method using electroosmosis while minimizing the direct or indirect effects of various electrochemical reactions occurring at the electrodes. The purpose is to provide a new method.

Another purpose is to retain or exchange the counter ion of the object to be dehydrated having an ion exchange group with a desired counter ion during dehydration.

To explain the present invention, when a hydrogel or paste-like material is dehydrated by electroosmosis, an electrolytic solution and the gel or paste-like material are separated through a diaphragm on the anode side and/or the cathode side. This dehydration method is characterized in that the gel or paste-like material is adjusted in contact with the water and at least during energization.

In the present invention, the object to be dehydrated is any hydrogel or paste containing an organic substance, an inorganic substance, or a mixture thereof.

Examples of objects to be dehydrated include water-containing gels or pastes containing organic substances used as stabilizers and thickeners. Such organic substances include agar,
Seaweed extracts such as carrageenan, farcelan, alginate, vegetable proteins such as soybean protein and wheat protein, vegetable polysaccharides such as starch, vegetable lipids such as soybean citrin, locust bean gum, guar gum, coumarind gum, quince seed, etc. Seed mucilage, resin-like mucilage such as gum arabic, gum tragacanth, gum karaya, pectin, plant mucilage such as arabic galaccum, microorganism-produced mucilage such as xanthan gum, pullulan, dextran, curdlan, gelatin, casein, albumin, etc. animal protein, animal fat such as egg yolk lecithin;
Starch derivatives such as starch phosphate and carboxymethyl starch; cellulose derivatives such as hydroxyethyl cellulose, carboxymethyl cellulose, methyl cellulose, and ethyl cellulose; alginic acid derivatives such as alginate propylene glycol ester; and synthetic polymers such as polyvinyl alcohol, polyvinyl pyrrolidone, and polyacrylic acid. Examples include molecules.

Furthermore, dehydration or solid-liquid separation of living tissue is also included as a hydrogel as a subject of the present invention.

The biological tissue referred to here refers to muscle tissue, nerve tissue, and connective tissue in animals, and particularly refers to fish and shellfish, meat of animals and birds, and porcine organs. In plants, it also refers to the epidermal tissue and soft tissue, particularly the roots, trunks, branches, flowers, leaves, fruits, seeds, buds, pericarp, and bark of plants.

Examples of inorganic substances include metal oxides that have a large number of 10H groups on the surface and become hydrated gels or pastes by absorbing water, such as silicic acid, silicates, aluminum hydroxide, cement, and china clay; Examples include metal hydroxides. In particular, in the process of manufacturing metal oxides and composite metal oxides used as catalysts for chemical reactions, water-soluble salts such as metal carbonates, nitrates, sulfates, and organic acid salts are dissolved in water. Then, it is neutralized with an alkali, precipitated (co-precipitated), dehydrated, and then calcined to obtain a metal oxide or composite oxide, and the method of the present invention is effective in this dehydration step.

The products obtained by this method (substances obtained by dehydration from gels or pastes) are of high quality because direct electrochemical effects and indirect acid and alkali chemical effects can be kept to a minimum. In addition to being able to be used as a product, if the substance has an ion exchange group, it has the characteristic of retaining or exchanging counterions with desired counterions. For example, the carrageenan powder obtained by this method has minimal chemical effects,
Furthermore, since it is retained or exchanged with a desired counterion during electroosmotic dehydration, it is imparted with arbitrary gelling properties.

The present invention will be explained in more detail.

Generally, a potential difference occurs at an interface where two substances come into contact, and this is called an electric double layer. Electroosmosis occurs when one substance is solid and the other is liquid (mainly water). When the solid side is charged either positively or negatively, the liquid side is charged with the opposite sign.

When an external electric field is applied to this system, the fixed solid side does not move, but the liquid side moves in the direction of the electric field.

The flow of liquid generated in this way is called an electroosmotic flow.

The potential difference at the contact interface between a solid and a liquid is called the interfacial electrostatic potential, but in electroosmosis, a different kind called the interfacial dynamic potential is rather important. This is the potential at a point that has advanced a distance into the liquid, and is the potential at a surface called slip (the interface between a layer of free water that can move by electroosmosis and a layer of non-free water that cannot).

In electroosmosis, the above-mentioned interfacial potential and free water are important, and it is thought that the magnitude of the electroosmotic flow increases as the interfacial potential increases and the amount of free water increases.

It is thought that this interfacial dynamic potential increases as the interfacial electrostatic potential increases, and decreases as the thickness of the non-free water layer increases.

Furthermore, the magnitude of the interfacial electrostatic potential governs the thickness of the non-free water layer and at the same time changes the gelation properties. Therefore,
The size and amount of this interfacial potential and free water are largely controlled by the type of object to be dehydrated, but include the amount of water contained in the gel or paste, and the ions of the rice and the object to be dehydrated. The amount of water contained in electroosmosis varies greatly depending on the counterion species of the group with exchange performance.
The field and counterion species are of particular importance.

Furthermore, since the gelling properties of the product vary greatly depending on the type of counterion, the selection of the counterion is particularly important.

For example, carrageenan is one of the natural polysaccharides.
While the electroosmotic property is high, the gelling properties change significantly depending on the type of counterion, and the gel strength and the concentration of the solution that can be gelled change depending on the type of counterion. For example, when the counterion is K, the gel strength is large. , and electroosmotic properties are preferred because they can produce gels with high water content. Furthermore, in gels obtained by gelatinizing gelatin or soluble proteins, the quality of the aqueous solution at the time of gelation is particularly important, and the electroosmotic dehydration efficiency changes significantly depending on the size of the aqueous solution at the time of gelation. Therefore, in the conventionally known method, even if an optimal region gel is produced during gelation, it will be affected by the acid and/or alkali generated in the electrode chamber during electroosmotic dehydration, and at least... There were disadvantages such as partial change, resulting in poor efficiency, and... changes, which made it impossible to maintain the gel shape, resulting in the formation of a solution, a base, or a gas, which flowed out of the apparatus along with water.

In addition, there are natural polysaccharides such as agar and carrageenan as substances having a large amount of groups having ion-exchange properties, and from hydrogels or pastes of these natural polysaccharides, conventionally known methods can be used. Efficient electroosmotic dehydration.

However, in the conventionally known method, as described above, the acid and/or alkali generated in the electrode chamber during energization penetrates into the gel or paste-like material, changing the water content in the gel or paste-like material. Alternatively, by changing the counter ion, the material to be dehydrated may be decomposed during dehydration, drying, and/or dissolving in hot water (regelling), resulting in coloring of the final product and a decrease in gelling properties. As a result, it was difficult to obtain high-quality products. In addition, there was a drawback that the counter ion changed during electroosmotic dehydration, making it impossible to obtain the desired product.

The method of the present invention is a dehydration method that significantly improves the drawbacks of the conventionally known methods described above.

In the present invention, adjusting the gel or paste to a ratio of 1:4 means to maintain the water containing the gel or paste in a specific optimal area at least during the application of electricity; There are no particular restrictions on the specific method, but for example, for gels or pastes where acidity is undesirable, methods to prevent the acid generated in the anode chamber from penetrating into the gel or paste, and/or Alternatively, this can be achieved by keeping the electrolyte in the anode chamber neutral or alkaline, and by this method, contact between the acid and the gel or the paste-like material and the acid can be significantly reduced.

In the present invention, as a specific method to prevent the above gel or paste-like material from coming into contact with acid, there are two methods: (1) Using a large amount of electrolyte to keep the change in the field small during energization; (2) The electrolyte in the anode chamber and the anode chamber; There is a method of sequentially mixing two electrolytes, but the following method is particularly suitable.

(1) Use the anode electrolyte as a buffer solution.

(2) A cation exchange resin is included in the anode electrolyte to neutralize the acid generated in the cathode chamber.

(3) A cation exchange resin layer containing an electrolyte is placed between the anode and the diaphragm to neutralize the acid and/or prevent the acid from penetrating into the gel or paste.

(4) A cation exchange membrane is placed in the diaphragm to neutralize the acid and/or prevent the acid from entering the gel or paste.

By combining the above methods as necessary, contact of gel or paste with acid can be minimized,
Can be dehydrated efficiently.

For dehydration of carrageenan hydrogel, the electrolyte solution is
By doing the above, chemical changes in carrageenan can be prevented, but from the viewpoint of preventing chemical changes, a state of 7 or higher is preferable. For water-containing gels or pastes other than carrageenan, it is particularly preferable to set the state to 7 or more. In addition, if alkalinity is inconvenient, the alkali generated in the cathode chamber is neutralized, but it is sufficient to prevent the alkali from penetrating into the gel or paste. By using a buffer solution of ≦7, an anion exchange resin, an anion exchange membrane, etc., the contact between the alkali and the object to be dehydrated can be minimized, and the gel or paste can be prepared. In addition, in the various methods described above, electrolyte buffers, ion exchange resins, and ion exchange membranes are used to retain or exchange the counter ion of the group having ion exchange performance of the object to be dehydrated with the target ion species. By using the ionic species or counter ion species as the ionic species, it is possible to achieve the purpose of retaining or exchanging the counter ion species while dehydrating.

Taking carrageenan as an example, the cation of the electrolyte, the cation exchange resin, and the counter ion of the cation exchange membrane can be combined with the desired carrageenan counter ion to retain or exchange the carrageenan counter ion during dehydration. This makes it particularly suitable.

In addition, by using K as a counter ion to carrageenan,
Since gels with high water content and gel strength can be obtained, in order to obtain carrageenan with high water content and high gel strength, the above electrolyte solution, buffer solution, cation exchange resin, and cation exchange membrane are required. It is desirable that the temperature of the gel or paste-like material is 7°C or higher.

It goes without saying that the same method can be used to achieve the desired inorganic compound by electroosmotic dehydration from an inorganic compound paste.

The ion exchange resin used in the present invention only needs to be capable of ion exchange with acid or alkali, and the types of base material and ion exchange group are not particularly limited, and may be selected as appropriate based on durability, equipment setting, price, etc. good~·.

In addition, the diaphragm referred to in the present invention is: ■) The material is dense and movement of water due to diffusion is small, 2) Electric resistance is low, 3) It is difficult for contaminants in the electrode liquid chamber to pass through, and 4) The membrane itself is It has characteristics such as not contaminating the object to be dehydrated, and 5) not allowing the object to be dehydrated to pass through.

What directly affects the object to be dehydrated due to the electrochemical reaction of the electrode is the oxidation reaction at the anode, and in order to prevent this, it is extremely suitable to use an anode diaphragm.

The diaphragm used in the present invention includes hydrophilic neutral membranes and ion exchange membranes. Typical examples of hydrophilic neutral membranes include cellulose, cellophane, polyvinyl alcohol, acidic cellulose, and especially ion exchange membranes. This is preferable for the reasons mentioned above.

For example, it is a cation exchange membrane in which the ion exchange group is a sulfone group, a carboxyl group, a phosphoric acid group, a phosphorous acid group, a phenolic hydroxyl group, a sulfonic acid amide group, a perfluoro tertiary alcohol, etc. These are anion exchange membranes made of quaternary ammonium bases, 1,2° tertiary amines, tertiary sulfonium bases, quaternary phosphonium bases, etc.

In addition, there are cation exchange membranes and anion exchange membranes in which these cation exchange groups and anion exchange groups are unevenly distributed within the membrane, amphoteric ion exchange membranes in which cation and anion exchange groups are uniformly distributed, and cation exchange membranes and anion exchange membranes in which cation and anion exchange groups are distributed uniformly. It is a composite ion exchange membrane that exists in layers and a mosaic ion exchange membrane in which regions of positive and anion exchange groups exist in parallel with the thickness direction of the membrane.

Also 10. In addition to the ion exchange groups described above, the ion exchange membrane contains other functional groups such as ester groups, amide groups, halogen groups, nitrile groups, acyl groups, phosphate ester groups, and hydroxyl groups.

Further, a single membrane or a combination of two or more of these membranes can also be used as the electrode diaphragm of the present invention.

In particular, as a cation exchange membrane, it is obtained from an ethylene copolymer or a resin composition containing an ethylene copolymer, -0)1 group- and -〇〇〇R group [wherein R is H, At least one hydrophilic group selected from hydrocarbon groups having 1 to 5 carbon atoms, ions that can form salts with alkali metals or other carboxyl groups] and 0.2 meq/g of sulfonic groups; In addition to the above properties, the membrane containing
It is suitable for reasons such as durability, flexibility, and the ability to handle it even in the atmosphere. The above film may be woven fabric, non-woven fabric, knitted fabric,
A composite membrane reinforced with a microporous membrane or the like is more suitable from the viewpoint of dimensional stability and durability.

Examples of the above ethylene copolymer include H, C, -
C6 hydrocarbon group, alkali metals, alkaline earth metals, rare earth metals, quaternary ammonium salts such as NH3, ions that can form salts with carboxylic acid groups such as metal ions other than the above)]. Copolymers obtained by copolymerizing with monomers or saponified products thereof are preferably used.

In addition, the resin composition containing the above ethylene copolymer contains 15% by weight or more of the ethylene copolymer and 85% by weight or less of the sulfonating agent, based on the total weight of the resin composition. A resin composition comprising a relatively inert thermoplastic resin and a relatively inert thermoplastic resin is suitable.

Briefly describing the manufacturing method, for example, based on the total weight, 15% by weight or more, for example, 95 to 30% by weight of the above ethylene copolymer, and 85% by weight, for example, 5 to 70% by weight of the sulfonating agent. For 100 parts by weight of a resin composition consisting of a relatively inert thermoplastic resin, at least one of the following is compatible with the resin composition and before, during, or after sulfonation. A mixture containing 5 to 200 parts by weight of a plasticizer extractable in 5
After melt-forming into a ~200 μm thick film and cooling and solidifying,
The above cation can be easily achieved by extracting the plasticizer with a sulfonating agent and then carrying out the sulfonation reaction, or by extracting at least a portion of the plasticizer with a solvent before sulfonation and then carrying out the sulfonation reaction. An ion exchange membrane can be obtained.

Such a cation exchange membrane has an exchange capacity of sulfonic groups of 0.2 to 4 meq/g and an electrical resistance of 0 in dilute sulfuric acid.
01~20Ω・0m2, preferably 0.05~5Ω・0
m2, more preferably 0.1 to 1 Ω·Cm”.

In such an ethylene copolymer, the ethylene content is 9
If it exceeds 7 mol %, the activity against the sulfonating agent decreases, the reaction time becomes longer, the productivity decreases, the membrane surface is subjected to the sulfonation treatment primarily, and the deterioration resistance tends to decrease. On the other hand, if the ethylene content is less than 82 mol%, the formability of the film by melt molding tends to decrease, and the oxidation resistance of the sulfonated ethylene copolymer tends to decrease.

Therefore, an ethylene copolymer containing 1L of 97 to 82 mol % of ethylene is particularly suitable.

In addition, as a thermoplastic resin that is relatively inert to sulfonating agents, it has a significantly slower sulfonation reaction than the above-mentioned ethylene copolymer, and can be easily and uniformly mixed using normal plastic processing methods. It is easy to obtain films of uniform quality, such as low density, high density polyethylene, polypropylene,
Polyolefin resins such as polybutene are preferred. The blending ratio is suitably 85% by weight or less based on the total weight of the resin composition. If it exceeds 85% by weight, the sulfonation reaction will be slow and the exchange capacity of sulfonic groups will be 0.2 meq.
Continuous production of cation exchange membranes weighing more than 1 gram tends to be difficult.

A plasticizer that is compatible with and extractable from the resin composition mentioned above is a plasticizer that is uniformly dispersed in an amount of at least 5 parts by weight per 100 parts by weight of the resin composition in the molten state of the resin, and that Any solvent may be used as long as it can form a thin film using a solvent and can be extracted from the film or membrane with a solvent or sulfonating agent that hardly dissolves the resin composition. For example, there are plasticizers commonly used in polyvinyl chloride resin such as diethyl phthalate and dioctyl phthalate, and liquid paraffin.
The amount added is 5 to 20 parts by weight per 100 parts by weight of the resin composition.
0 parts by weight is suitable. These mixing and film formation are usually carried out by known methods. The thickness of the film is 5-20
0 μm is appropriate.

In addition, the ions that can form salts with other carboxyl groups include, for example, Mg and Ca.

In addition to divalent metal ions such as Zn''+ and trivalent metal ions such as At3+, it refers to cations that can form salts with carboxyl groups such as NH4+, and for the reasons described above, depending on the target object to be dehydrated. You can choose as appropriate.

In addition, in the present invention, as another particularly suitable cation exchange membrane, Japanese Patent Application No. 56-116152, Japanese Patent Application No. 56-2
11496 and Japanese Patent Application No. 56-211497, or a resin composition containing a vinyl chloride resin, and containing a small amount (both 0.1 meq/g of sulfonic groups). Ion exchange membranes are preferred because they have a small diffusion coefficient for acids, alkalis, etc., like the cation exchange membranes described above.

The present invention also includes a case where the above-mentioned diaphragm is used only on one side of the anode or the cathode, and no diaphragm is used on the other side. In this case, as mentioned above, it is preferable to arrange a diaphragm on the anode side for the purpose of preventing oxidation.

Of course, better results can be obtained by using diaphragms on both sides of the anode and cathode.

There are three cases in which diaphragms are used on both sides:

(1) When ion exchange membranes are arranged on both sides, each of the anode and cathode contains ions selected from cation exchange membranes, anion exchange membranes, amphoteric ion exchange membranes, composite ion exchange membranes, mosaic ion exchange membranes, etc. An exchange membrane is provided.

In this case, the following arrangement can be cited as a preferable example.

Anode side Cathode side aspect 1. :@Ion exchange membrane Cation exchange membrane embodiment 2:
Cation exchange membrane Anion exchange membrane Embodiment 3; Anion exchange membrane Cation exchange membrane Embodiment 4: Anion exchange membrane Anion exchange membrane (li) An ion exchange membrane is arranged on either the VJA electrode or the cathode, and the other When a hydrophilic neutral membrane is placed on both sides (iii) When a hydrophilic neutral membrane is placed on both sides, the electroosmotic properties of the membrane create a gel. It is preferable to arrange a cation exchange membrane at the cathode; however, when dehydrating the object to be dehydrated by electroosmosis, for the purpose of the present invention, it is preferable to arrange a cation exchange membrane at the anode, for example. ,Also,
The counter ion is preferably one that can release other cations and anions by ion exchange with the acid.

When the object to be dehydrated is a carrageenan hydrogel and the counter ions are cations, these cations easily permeate through the cation exchange membrane, and most of the free water following the movement of the counter ions becomes cations. A cation exchange membrane is suitable as the diaphragm because it is blocked by the exchange membrane and flows out of the system along the wall of the cation exchange membrane.

In addition, in the present invention, the shape of the hydrogel is not particularly limited, and can be plate-shaped, granular, or rod-shaped to enable efficient dehydration. Particularly, granular or rod-shaped is preferable because it is easy to set the gel in the apparatus.

When the object is a gel, the portion 5 in FIGS. 1 to 5 may contain only the gel itself or the gel in a cloth bag, and does not necessarily need to constitute a chamber. Even in the case of paste, it is possible to dehydrate it without constructing a chamber by wrapping it in cloth. When the part 5 is used as a chamber, it is preferable that the bottom and wall surfaces of the chamber are configured so as to follow the volumetric contraction of the gel or paste-like material during dehydration. By applying slight pressure from both sides of the positive and negative electrode chambers,
As the water content decreases, the volume of the gel etc. decreases, and the distance between the anion and ion exchange membranes gradually decreases, thus achieving the purpose of dehydration.

In the present invention, the gel or paste-like material is divided into a plurality of parts as shown in Fig. 5, and one semi-transparent film 12 is inserted into each divided surface, thereby increasing the dehydration speed and dehydration energy efficiency. This is particularly effective under conditions that maximize the electroosmotic properties of the carrageenan gel paste.

Furthermore, in the case of carrageenan hydrogel, it is particularly effective when the semipermeable membrane is a cation exchange membrane. This is for the same reason that it is preferable to use a cation exchange membrane as a diaphragm during carrageenan dehydration.

Generally, in a dehydration method in which a gel is dehydrated by electroosmosis, dehydration occurs due to the additive effects of the electroosmotic properties of the ion exchange membrane and the electroosmotic properties of the gel itself. With this method, if a gel of suitable strength is obtained, dehydration is extremely difficult using normal methods.
Highly viscous and highly concentrated solutions can be easily dehydrated with high energy efficiency.

However, especially in solutions with a high water content, gelation tends to occur.To use this excellent method, it is necessary to adjust the solution to a level where gelation is likely to occur, or to adjust the solution to a concentration where gelation is likely to occur. Especially the gel obtained by preparing the solution must be concentrated.

As mentioned above, it is extremely difficult to perform electroosmotic dehydration using conventionally known methods.

However, according to the present invention, it is possible to efficiently produce a desired product of high quality even from gel or paste, which has been difficult to produce using conventionally known methods. In addition, in the present invention, JP-A-54-141387, JP-A-54-15
It goes without saying that by using the dehydration method of No. 3782 in combination, dehydration can be carried out more efficiently.

The water content, sulfone group exchange capacity, and electrical resistance in dilute sulfuric acid used in the present invention are values measured by the following methods.

Moisture content (wt, %) (Does not include water of crystallization or combined moisture that cannot be removed by drying.) (Place a well-washed weighing tube in an electric dryer adjusted to 1160°C, and leave it for day and night. Transfer to a desiccator, weigh after 30 minutes, and mark as Wo.

(2) Place 3 to 4 C-angle samples into a weighing tube and weigh them to determine Wl.

(3) After leaving it in the electric dryer for a day and night, it was transferred to a desiccator, and after 30 minutes, it was weighed and determined as WQ.

+4+ (11, +2], (From 31, the water content can be determined by the following formula.

Moisture content (%) -w, -w voice - x 100W, -W.

Exchange capacity (milliequivalent/gram) A hydrophilized sulfonic acid (-8o3H) type membrane is placed in a certain amount of calcium chloride (IN) aqueous solution to achieve equilibrium, and the hydrogen chloride generated in the solution is reduced to 0. The value obtained by titrating an IN aqueous solution of caustic soda (potency -f) using phenolphthalein as an indicator and dividing the value X (CC) by the dry weight W (Li) in the potassium salt state.

Measuring device (JIS) filled with dilute sulfuric acid (specific gravity -1,2)
(according to C2313), the sample is placed between the electrodes L-L, and the
Measure the voltage drop across the sample when a constant DC current with a current density of 25 mA/C, m'' is applied at 3°C, and use the value calculated from the following formula as the electrical resistance in dilute sulfuric acid.

R - Electrical resistance of the sample in dilute sulfuric acid (Ω cm2) V, - Voltage drop when the sample is not set (V) VQ - Voltage drop when the sample is set (V) Further details of the present invention are given in Examples Explain.

Example 9 A copolymer of 4.2 mol% ethylene and 5.8 mol% methyl methacrylate was saponified (degree of saponification -60 mol%).
) and 1C00C obtained by neutralization (degree of neutralization -30 mol%)
25% by weight of ethylene copolymer (M, I = 1.0) having H3, -COOH and -COONa groups
Weight% high density polyethylene (density -〇, 955'
i/cm3Ml = 7) in a kneader at 190
°C"'e 30 minutes of kneading, and then the above resin composition 100%
43 parts by weight of liquid paraffin (manufactured by Kokusan Kagaku Co., Ltd.) was added to each part by weight, and the mixture was further kneaded at 190°C for 30 minutes. Next, the resin mixture was thermoplasticized in an extruder at a temperature of 180°C, extruded through a circular die,
The thickness of the original fabric is 35μ by quenching with water at 20°C from the surrounding area.
A film of m was obtained.

The film was then immersed in 1.1.1-)lichloroethane at room temperature for about 10 minutes to extract liquid paraffin.

Next, it was placed in fuming sulfuric acid containing 12% of free sulfur trioxide, treated at 35°C for 5 minutes, washed with concentrated sulfuric acid, diluted sulfuric acid, and water in that order, neutralized with an aqueous potassium hydroxide solution, washed with water, and dried. An ion exchange membrane was obtained.

This membrane had an exchange capacity of 215 milliequivalents of 1 gram, and had a low electrical resistance of 0.15 Ω·cm 2 in dilute sulfuric acid.

Example 9 Copolymer of 2.3 mol% ethylene and 7.7 mol% ethyl acrylate (MI-'8) 40% by weight of high-density polyethylene (density -0,955'l 7c)
m3, MI=7) was explicitly melt-kneaded in a kneader in the same manner as in Example 1, and then 67 parts by weight of liquid paraffin was added to 100 parts by weight of the resin composition, and further melt-kneaded.

Next, the resin mixture was extruded using an extruder equipped with a circular die (dice temperature -150°C) to obtain a film having a thickness of 25 μm.

Hereinafter, extraction of liquid paraffin using a method similar to Example 1,
A sulfonation treatment was performed to obtain a cation exchange membrane having 2.35 milliequivalents/gram of sulfone groups.

The electrical resistance of this cation exchange membrane in dilute sulfuric acid is 030Ω.
・It was extremely low at Cm2.

Examples Vinyl chloride-vinyl acetate copolymer resin (vinyl chloride content>95% by weight, degree of polymerization = isoo, manufactured by Chisso Corporation,
Nipolitsu) Ml () 60 parts by weight and chlorinated polyethylene (
To 100 parts by weight of the mixture, 100 parts by weight of dioctyl phthalate and an organic tin malate stabilizer (TVSN20, manufactured by Nitto Kasei Co., Ltd.) were added to 100 parts by weight of the mixture.
00E4) was added to the above resin mixture at a ratio of 55 parts by weight per 100 parts by weight of the vinyl chloride-vinyl acetate copolymer resin, and melt-kneaded in a kneader at 160°C for 30 minutes. Vinyl resin/chlorinated polyethylene/
A resin composition containing a plasticizer/stabilizer was obtained.

Next, the resin composition was extruded using an extruder, and
It was molded into a film with a thickness of μm.

The above film was reacted with fuming sulfuric acid containing about 12% by weight of free sulfur trioxide at 40'C for 25 minutes, washed in the order of concentrated sulfuric acid, diluted sulfuric acid, and water, and then oxidized to 31% by weight. The membrane was neutralized with an aqueous potassium solution, washed with water, and dried to produce a cation exchange membrane having 1.08 milliequivalents/gram sulfone group and an electrical resistance of 0.320·Cm2 in dilute sulfuric acid.

Example 9 50 parts by weight of a copolymer of 2.3 mol% ethylene and 77 mol% ethyl acrylate (MI=2) and a vinyl chloride-vinyl acetate copolymer resin (vinyl chloride content>95% by weight), polymerized degree -1500 Nipoli (manufactured by Chisso Co., Ltd.) M
l) Tri-blend 50 parts by weight of () at room temperature,
(A)/(A)+CB) -0.5 resin mixture was obtained. Next, 67 parts by weight of vinyl chloride resin
Parts by weight of dioctyl phthalate and 5.5 parts by weight of an organotin malate stabilizer (TVSN2 manufactured by Nitto Kasei Co., Ltd.)
000E4) to the above resin mixture and kneader
The mixture was kneaded for 30 minutes at a temperature of 160°C, and then extruded using an extruder at a temperature of 190°C.
A film with a thickness of 40 μm was molded.

The above film was reacted with fuming sulfuric acid containing about 12% by weight of free sulfur trioxide at 40°C for 4 minutes, washed in the order of concentrated sulfuric acid, diluted sulfuric acid, and water, and then washed with 31% by weight of water. Neutralized with an aqueous IJ solution, washed with water, and dried to form a cation having 162 milliequivalents/gram of soluphonic groups and an electrical resistance of 0.210 Cm2 in dilute sulfuric acid. An exchange membrane was obtained.

Example 1 Electrode plates (anode plate 1 and cathode plate 2) in the apparatus shown in FIG.
The carbon plate and both electrode solutions in the anode chamber 6 and cathode chamber 7 are 1 wt% potassium sulfate aqueous solution,
The cation exchange membrane prepared in Experimental Example 1 was used as the anode diaphragm 3 and the cathode diaphragm 4, and nine layers of cation exchange resin with a thickness of 0.5 cm [granular polystyrene potassium sulfonate cation exchange resin (exchange capacity 4.4 Mi IJ equivalent/gram)
] and the anode as the diaphragm 8 [made by Asahi Kasei Kogyo Co., Ltd. (thickness - 200 μm, porosity -55%)]
Place a 1 cm thick agar gel (water content 99%) (
Sample 5) was subjected to electroosmotic dehydration for 15 minutes under a constant voltage condition of 15V. Note that during electroosmotic dehydration, the agar gel field was maintained at 7 or higher.

Next, it was dried with hot air at a temperature of 80°C to obtain white agar. This agar was dissolved again in hot water and after cooling, an agar gel with a water content of 99% was prepared, and the gel strength and transparency were almost as good as before electroosmotic dehydration.

In addition, the dehydration rate by electroosmotic dehydration is 90% energy efficiency (dehydration amount per IKWE electricity) 40kg/KwI (
It was extremely good.

Example 2 Except for changing the cation exchange membrane to the membrane of Experimental Example 2
In □, agar gel was dehydrated in the same manner as in Example 1, and as in Example 1, good agar was obtained with good productivity and efficiency.

Example 3 The cation exchange resin used in Example 1 was placed in the anolyte (without using the polyethylene microporous membrane), and agar gel was dehydrated in the same manner as in Example 1. The results were as in Example 3. 1
Similarly, good agar was obtained with high productivity and efficiency.

Example 4 In the apparatus shown in FIG. 2, electrode plates (anode plate 1 and cathode plate 2
), both electrode solutions in the carbon plate, the anode chamber 6 and the cathode chamber 7 were treated with l'wt% potassium sulfate aqueous solution, and the cations prepared in Experimental Example 3 were used as the anode diaphragm 3 and cathode diaphragm 4. Using an exchange membrane, a potassium hydroxide aqueous solution IO is added to the anolyte in the anode chamber 6, and a sulfuric acid aqueous solution IO is added to the catholyte in the cathode chamber 7.
Drip 1 c and adjust the thickness to 6 to 8 in each case.
Agar gel (water content 99%) (sample 5) with a thickness of m was subjected to electroosmotic dehydration under the conditions of Example 10. When electricity is applied, agar gel...
It was held in Hakebo 7.

Then, it was dried with hot air at a temperature of 80°C to obtain white agar.

As in Example 1, an agar gel with a water content of 99% was prepared from the above agar, and the gel strength and transparency were both good.

In addition, the dehydration rate and energy efficiency by electroosmotic dehydration were also good as in Example 1.

Example 5 A 1.2 cm thick carrageenan gel (96% water content) was prepared using the apparatus used in Example 4, except that the potassium hydroxide aqueous solution and the sulfuric acid aqueous solution were not added dropwise. Electroosmotic dehydration was performed for 30 minutes under IOV constant voltage conditions. Next, the above carrageenan gel was dried with hot air at a temperature of 80°C.

When the above carrageenan was dissolved in hot water and cooled to ]0'C, a hydrogel with excellent gel strength even at a water content of 98% was obtained.

Note that when the carrageenan gel before electroosmotic dehydration was dried with hot air at a temperature of 8° C. and then dissolved in hot water again, no gel was formed at a water content of 98%. When we measured the potassium content in electroosmotic dehydrated carrageenan, we found that
It was higher than the potassium concentration in carrageenan before electroosmotic dehydration.

Example 6 Gelatin gel (water content = 95) instead of carrageenan gel
Electroosmotic dehydration was carried out for 45 minutes under a constant voltage condition of 20 V using the same apparatus as in Example 5 except that a gelled solution of Ta-9 was used. During electroosmotic dehydration, the gel does not turn into a paste and is stable, with a dehydration rate of 50% and an energy efficiency of 5 kg/xw.
It was good with H.

Comparative Example 1 In the apparatus shown in Fig. 3, the anode diaphragm 3 and the cathode diaphragm 4 were made of cellulose (thickness -4 pm), an aqueous potassium sulfate solution of I wt% was used as the electrode solution, and an agar gel with a thickness of l cm was used. (Moisture content = 99%) (Sample 5) was electroosmotic dehydrated for 15 minutes under a constant voltage condition of 15V.

When the agar was then dried with hot air at a temperature of 80°C, the agar turned black. Further, the dehydration rate was 70% and the energy efficiency was Xokg/KWH, which was inferior to Example 1.

Comparative Example 2 Except for changing the buffer to 1% potassium sulfate aqueous solution,
Carrageenan gel was subjected to electroosmotic dehydration under the same conditions as in Example 5.

Then, after drying with hot air at a temperature of 80°C, it was dissolved in hot water again, and a 2% aqueous solution (98% water content) did not gel, and small precipitates floated in the aqueous solution. Ta.

Comparative Example 3 Electroosmotic dehydration of gelatin gel was attempted in the same manner as in Example 6 except that the buffer solution was replaced with a 1% potassium sulfate aqueous solution, but the gelatin gel turned into a paste during energization, and the water in the gelatin gel chamber It leaked out from the outlet.

Example 7 In the apparatus shown in FIG. 4, electrode plates (anode plate 1 and cathode plate 2
), a 5 wt % potassium sulfate aqueous solution was used as the carbon plate, both electrode solutions in the anode chamber 6 and cathode chamber 7, and the cation exchange membrane prepared in Experimental Example 1 was used as the anode diaphragm 3 and cathode diaphragm 4. In addition, 9 layers of 0.5 cm thick cation exchange resin [granular polystyrene sulfonate potassium cation exchange tfjJ resin (exchange capacity 44 milliequivalents/gram)] and the polyethylene used as the membrane 8] The anode chamber was divided with a microporous membrane, and 20 cm of plate-shaped carrageenan gel (water content 98%) (sample 5) with a thickness of 12 cm was added.
Electroosmotic dehydration was performed for 10 minutes under constant voltage (DC) conditions of V.

During this period, the rice fields in Karagienanger were 7 or more.

Then, it was dried with hot air at a temperature of 8.0°C to obtain dehydrated carrageenan.

When the carrageenan was redissolved to a concentration of 2 wt % and cooled, the transparency and gel strength were as good as the carrageenan gel before dehydration.

The dehydration rate with electroosmotic dehydration is 85%, and the energy efficiency (amount of water removed per IKWH electricity) is 7 kg/
xwH, which was extremely good.

Example 8 In the apparatus shown in FIG. 3, the electrode plate, negative, diaphragm, and anode chamber 7
The electrolyte used was the same as in Example 7, and a 3 wj% potassium hydroxide solution was used as the electrolyte in the anode chamber 6.
1.2 cm thick plate-shaped carrageenan gel (water content 9
8%) was subjected to electroosmotic dehydration for 15 minutes under IOV constant voltage (DC) conditions.

During this period, the rice fields in Carrageenanger were over 7.

Thereafter, the gel was dried, redissolved, and gelated in the same manner as in Example 1, and the transparency and gel strength were as good as those of the carrageenan gel before dehydration. The dehydration rate with electroosmotic dehydration is 85%, and the energy efficiency is 11k.
g/Kwn, which was good.

Example 9 In the apparatus shown in FIG. 3, an electrolytic solution (1 wt % potassium sulfate aqueous solution containing the cation exchange resin used in Example 7) was added to the anode chamber 6 instead of the potassium hydroxide aqueous solution.
Electroosmotic dehydration was carried out under the same conditions as in Example 8, except that the cation exchange membrane prepared in Experimental Example 2 was used as the anode and diaphragm. During dehydration,
The anolyte field was kept above 5.

Thereafter, the product was dried, redissolved, and gelated in the same manner as in Example 7, and as in Example 7, good results were obtained.

The dehydration rate in electroosmotic dehydration is 85%.

Energy efficiency was good at 10 kg/xwi+.

Example 0 Electroosmotic dehydration was carried out in the same manner as in Example 8, except that the electrolyte in the anode chamber 6 was replaced with a buffer solution (pH=6) consisting of a mixed solution of citric acid and potassium citrate.

The results were good as in Example 8.

Comparative Example 4 The electrolyte in the anode chamber 6 was changed to a 5 wt% potassium sulfate aqueous solution,
Electroosmotic dehydration was carried out under the same conditions as in Example 8 except that the anode diaphragm was replaced with cellophane.

When drying and regelation were attempted in the same manner as in Example 8, gelation did not occur and a precipitate was formed in the solution.

In addition, the anode diaphragm 3 of carrageenan gel after electroosmotic dehydration
When the area that was in contact with the rice field was measured, it showed strong acidity of less than 3.

Furthermore, although the redissolved solution was neutralized with potassium hydroxide, no gelation occurred, and it was clear that the carrageenan had been chemically changed by the acid.

Example 11 The cation exchange membrane prepared in Experimental Example 4 as a negative diaphragm,
Electroosmosis was performed in the same manner as in Example 7, except that both electrode solutions were replaced with a 5 wt % sodium sulfate aqueous solution, the counter ion of the cation exchange resin was replaced with sodium, and the carrageenan gel was made into a paste using a mixer and wrapped in saran cloth. Dehydrated.

During dehydration, most of the counterions of the sulfate ester of carrageenan were replaced with sodium, yielding carrageenan with the desired low gel strength properties.

Example 12 In the apparatus shown in FIG. 5, electrode plates (@electrode plate 1 and cathode plate 2)
) Both electrode solutions in the anode chamber 6 and cathode chamber 7, anode diaphragm 3 and cathode diaphragm 4, cation exchange resin 9, and microporous membrane as diaphragm 8 were all the same as in Example 7, and 2I
A rod-shaped carrageenan gel (water content = 95%) (sample 5) of +IIIφ x 5 cm was set parallel to the electrode, and the carrageenan was divided into 1 cm thick pieces using the cation exchange membrane prepared in Experimental Example 3 as the semipermeable membrane 12. Then, electroosmotic dehydration was performed for 45 minutes under a constant voltage condition of 15V.

All Carrageenanger fields are dehydrated with a score of 7 or above.
The dehydration rate was 50% and the energy efficiency was 20 kgZ catties, which was good.

When the above gel was dried, redissolved, and regelatinized in the same manner as in Example 7, a gel with greater gel strength than the hydrous gel before dehydration was produced.

[Brief explanation of drawings]

1 to 5 are explanatory diagrams showing apparatuses used in Examples and Comparative Examples of the present invention. 1... Anode plate 2... Cathode plate 3... Anode diaphragm 4... Cathode diaphragm 5... Sample
6... Anode chamber 7... Cathode chamber 8.
・・Diaphragm 9・Cation exchange resin] 0・Potassium hydroxide aqueous solution 11・Sulfuric acid aqueous solution 12・Semipermeable membrane Figure 2 Figure 3 Figure 5

Claims (9)

[Claims] (1) When dehydrating a hydrogel or paste-like material by electroosmosis, the electrolytic solution and the gel or paste-like material are brought into contact via a diaphragm on the anode side and/or the cathode side, and At least 2 degrees Celsius while energized
・This is a dehydration method characterized by preparing a paste-like material. (2) The dehydration method according to claim 11, wherein the electrolyte level on the anode side and/or the cathode side is adjusted at least during energization. (3) Claim No. 1 in which the electrolyte is a buffer solution
) or (2). (4) The dehydration method according to any one of claims (1) to (3), wherein the electrolytic solution contains an ion exchange resin. (5) The dehydration method according to any one of claims 11 to (4), which has an ion exchange resin layer containing an electrolyte between the anode and the diaphragm and/or between the cathode and the diaphragm. (6) Dehydration according to claim 4 or 5, wherein the ion exchange resin on the electrode side is a cation exchange resin and/or the ion exchange resin on the cathode side is an anion exchange resin. Method. (7) The dehydration method according to any one of claims (1) to (6), wherein the diaphragm on the anode side is a cation exchange membrane or an anion exchange membrane. (8) The dehydration method according to any one of claims (1) to (6), wherein the diaphragm on the two cathode sides is a cation exchange membrane or an anion exchange membrane. (9) @The ion exchange membrane is obtained from an ethylene copolymer or a resin composition containing an ethylene copolymer, and -OH
group and -coon group [wherein H1 has 1 to 5 carbon atoms]
A membrane containing at least one type of hydrophilic group selected from ions capable of forming salts with hydrocarbon groups, alkali metals or other carboxyl groups and at least 0.2 meq/g of sulfonic groups. A dehydration method according to claim (7). 00) The cation exchange membrane is a membrane obtained from a vinyl chloride resin or a resin composition containing a vinyl chloride resin and containing at least 0.1 meq/g of sulfonic groups. Dehydration method described in ). 0) The dehydration method according to claim (1), wherein the hydrogel or paste is a hydrogel or paste of galrageenan. (b) At least on the anode side, the electrolytic solution and the gel or paste-like material are brought into contact through a diaphragm, and the gel or paste-like material is maintained at a ratio of 3 or more. Dehydration method.