JPH07108367B2 - Dehumidification method - Google Patents

Description

The present invention relates to a dehumidifying / humidifying method. More specifically, the present invention relates to a dehumidifying / humidifying method in which water vapor contained in an inorganic gas is separated by a membrane.

[Conventional technology]

Conventionally, various dehumidification methods have been carried out to separate water vapor from inorganic gas containing water vapor. Generally, water vapor is separated by contacting a hygroscopic solid such as silica gel, quick lime, calcium chloride, and molecular sieve or a hygroscopic liquid such as concentrated sulfuric acid and lithium chloride with an inorganic gas containing water vapor. The method and the method of cooling the inorganic gas to reduce the saturated steam pressure and condensing the water in the gas to separate the water are carried out.

However, the following problems have been pointed out in these methods. That is, in the former case, there is a limit to the hygroscopicity of the solid or liquid to be used, it is impossible to continuously dehumidify, and moreover, the hygroscopic agent must be frequently regenerated. On the other hand, in the latter method, the temperature of the dehumidified gas is considerably lowered, so that the temperature must be adjusted during use, and a large amount of energy is consumed.

Recently, a dehumidification method by membrane separation has been proposed as a dehumidification method that solves these problems (Japanese Patent Laid-Open No. 54-152679), and future development as an energy-saving process can be expected.

[Problems to be solved by the invention]

The method described in the above publication is a method of separating water vapor by bringing a gas mixture containing water vapor into contact with a polymer thin film, specifically, copper ammonia rayon regenerated cellulose thin film, diacetyl cellulose thin film, natural. A method of dehumidifying using a nonionic polymer thin film such as rubber is disclosed. However, with the method described in the publication, dehumidification can be performed continuously and without changing the temperature of the dehumidified gas, but the amount of treated air is small and dehumidifying ability is still insufficient, making it difficult to put to practical use.

Accordingly, an object of the present invention is to provide an industrially advantageous dehumidifying / humidifying method capable of dehumidifying and humidifying from an inorganic gas containing water vapor using a membrane with high performance.

[Means for solving problems]

The present inventors have conducted extensive studies to achieve such an object, and surprisingly, a membrane composed of a polysaccharide polymer substance having an ionized group, which has never been used as a separation membrane for dehumidification in the past. It has been found that the use of the above-mentioned agent enables dehumidification and humidification with an extremely high moisture permeability, and has reached the present invention. That is, the present invention is a polymer film composed of a polysaccharide polymer substance having an ionized ionic group when the water vapor-containing inorganic gas is brought into contact with the film to separate the water vapor in the inorganic gas. This is a dehumidifying / humidifying method characterized by using (hereinafter referred to as an ionized polysaccharide-based film). In the present invention, the inorganic gas refers to a gas in which one or more of air, hydrogen, oxygen, nitrogen, helium, argon, carbon dioxide, etc. are mixed.

In the present invention, the ionized ionic group is a group ionized to a cation or an anion, and includes all groups capable of forming a salt, but among them, practically, a sulfuric acid ester residue, a sulfonic acid residue, A salt of a carboxylic acid residue, a phosphoric acid ester residue and a phosphonic acid residue, or a metal complex group having a nitrogen atom coordinated with an ammonium group and a polyvalent metal ion is preferable. As an ammonium group, a general formula -N ⁺
HnR ₄ -n (wherein R is a hydrocarbon group having 1 to 6 carbon atoms, n
Is an integer of 1 to 4), —NHCH ₂ CH ₂ NH ₂ ,
-NHCH ₂ CH ₂ NHCH ₂ CH ₂ NH ₂ and other polyamines, Examples thereof include an ammonium group and the like formed from an amine having a heterocyclic structure. Further, the group having a nitrogen atom coordinated to a polyvalent metal ion is a metal complex group formed by the coordinate bond of the nitrogen atom on the polysaccharide molecule to the polyvalent metal ion, and has a general formula (Where x is an integer of 1 to 6 in terms of the number of nitrogen atoms coordinated to the metal ion, y is an integer of 2 to 4 in valency of the metal ion, and M is a metal) It represents). The ionized polysaccharide membrane used in the present invention is a membrane having one or more groups selected from the above ionic group group.

The ionized polysaccharide-based membrane used in the present invention is a membrane composed of a cationic polysaccharide salt or an anionic polysaccharide salt,
It is preferable in terms of film formability, mechanical strength, and film performance. Examples of the membrane composed of such a cationic polysaccharide salt include chitosan salts such as chitosan sulfate and chitosan acetate, and N-.
Chitosan such as acylated chitosan, phosphorylated chitosan, carbomethoxylated chitosan and its derivative salts, aminocellulose, N-methylaminocellulose, N, N-dimethylaminocellulose, diethylenetriaminocellulose,
Examples thereof include salts of N-substituted cellulose such as piperazyl cellulose, and cationic cellulose derivative salts containing an amine titan atom such as diethylaminoethyl cellulose, aminoethyl cellulose and cyanuric chloride. Further, as the film composed of an anionic polysaccharide salt, salts of natural polysaccharides such as alginic acid, pectic acid, chondroitin sulfate, hyaluronic acid and xanthum gum and their derivatives, for example, partially methyl esterified alginic acid, carbomethoxylated alginic acid, phosphorus. Examples of the membrane include salts such as oxidized alginic acid and aminated alginic acid, and salts of semi-synthetic polysaccharides such as CM cellulose, cellulose sulfate, cellulose phosphate, sulfoethyl cellulose, phosphoethyl cellulose, phosphorylated guar gum, and phosphorylated chitin. Among them, in the present invention, a film composed of a chitosan salt, a chitosan derivative salt, an alginate salt, an alginic acid derivative salt, and a cationic or anionic cellulose derivative salt is further preferable in terms of film-forming property, mechanical strength, and film performance. The preferred membrane.

The dehumidifying / humidifying film of the present invention is a film containing the ionized polysaccharide-based polymer as a main component, and is obtained by blending with a polymer compatible with the ionized polysaccharide, for example, chitosan and PV.
A blend film with A, a blend film with a blend film of alginic acid and PVA, a graft film with a hydrophilic vinyl monomer such as acrylic acid grafted to alginic acid, and the like are also included.

In the ionized polysaccharide-based membrane of the present invention, the ionized group needs to form a salt with the counter cation and / or the counter anion for the group. When the ionized group is an anionic group such as a sulfuric acid ester residue, a sulfonic acid residue, or a phosphonic acid residue, as a counter cation for the group, lithium, sodium, potassium, rubidium, an alkali metal such as cesium, Beryllium, magnesium, calcium, strontium, barium and other alkaline earth metals, titanium, chromium, manganese, iron, cobalt, nickel, copper, zinc, silver, rhodium, zirconium, cerium, europium and other transition metals, aluminum, tin, Ions of metals such as lead that belong to groups 3B and 4B of the periodic table,
General formula N ⁺ HnR ₄ -n (R is a hydrocarbon group having 1 to 4 carbon atoms, n is an ammonium ion represented by an integer of 1 to 4, Polyamines, etc. Examples thereof include an ammonium ion and a pyridinium ion produced from an amine having a heterocyclic structure such as When the ionized group is an ammonium group, the anion for the group is a halogen ion such as chlorine ion or bromine ion, an anion generated from an inorganic acid such as sulfuric acid, phosphoric acid or nitric acid, formic acid, acetic acid, propionic acid or methanesulfone. acid,
Anions generated from organic acids such as oxalic acid, malonic acid, succinic acid, fumaric acid, maleic acid, glutaric acid, phthalic acid, isophthalic acid, terephthalic acid, trimellitic acid, citric acid, pyromellitic acid, ethylenediaminetetraacetic acid, and aconittic acid Is mentioned. Further, as a counter anion of the metal complex group having a nitrogen atom coordinated to a polyvalent metal, sulfuric acid,
Examples thereof include anions generated from inorganic acids such as phosphoric acid, nitric acid and hydrohalic acid, and anions generated from organic acids such as acetic acid. Further, in the present invention, when a cation and an anion are present in the same polymer and they are ionized intramolecularly and / or intermolecularly, or when the counterion is a polyion (for example, alginic acid and polyethyleneimine, chitosan Polyacrylic acid, ion complex such as alginic acid and chitosan) and the like are also included.

In order to more specifically describe the membrane used in the method of the present invention, among the ionized polysaccharide-based membranes, a membrane composed of a chitosan salt or a chitosan derivative salt (hereinafter referred to as a chitosan-based polysaccharide membrane), alginic acid. A typical example is a membrane made of a salt or an alginic acid derivative salt (hereinafter referred to as alginic acid-based polysaccharide membrane) and a membrane made of a cationic or anionic cellulose derivative salt (hereinafter referred to as a cellulose-based polysaccharide membrane). Describe in detail.

First, a chitosan-based polysaccharide film, which is a typical example of a cationic polysaccharide-based film, will be described. The chitosan-based polysaccharides refer to chitosan and its derivatives, but such chitosan-based polysaccharides form a salt in a dilute aqueous solution of acetic acid, hydrochloric acid, etc. and are easily dissolved, and when they are contacted with an alkaline aqueous solution, they are again dissolved. It has the property of solidifying and precipitating. Therefore, a chitosan film can be obtained by dissolving chitosan in the above solvent and contacting the obtained solution with an alkaline aqueous solution by flushing or by air-drying to form a dry film and then contacting with an alkaline aqueous solution. . Chitosan used in the present invention has a degree of deacetylation.
It is preferably 50% or more. In order to ionize the chitosan-based polysaccharide membrane, the amino group of the acid and chitosan may be neutralized or partially neutralized to form an ammonium salt. Acids that can be used here include inorganic acids such as hydrochloric acid, nitric acid, bromic acid, sulfuric acid and phosphoric acid, acetic acid, methanesulfonic acid, formic acid, propionic acid, oxalic acid, malonic acid, succinic acid, fumaric acid, maleic acid, Examples thereof include glutaric acid, phthalic acid, isophthalic acid, terephthalic acid, trimesic acid, trimellitic acid, citric acid, aconitic acid, sulfobenzoic acid, pyromellitic acid, and ethylenediaminetetraacetic acid. Upon use, one kind or two or more kinds of acids can be used. To ionize the chitosan-based polysaccharide membrane using these acids, for example, the chitosan-based polysaccharide membrane may be immersed in a solution containing these acids and ionized.

Further, as a method of ionizing the chitosan-based polysaccharide film,
There is also a method of forming a metal complex salt using a polyvalent metal ion. That is, it is a method in which the amino group of chitosan is coordinated with a metal ion to form a metal complex salt. Examples of such metal ions include polyvalent metal ions generated from beryllium, magnesium, iron, nickel, cobalt, copper, zinc, chromium, aluminum, titanium and the like. When used, one or more polyvalent metal ions can be used. Examples of such metal ion sources include Cr ₂ (SO ₄ ) ₃ , FeSO ₄ , CoSO ₄ , NiSO ₄ , and C.
uSO ₄ , Fe ₂ (SO ₄ ) ₃ , MnSO ₄ , BeSO ₄ , MgSO ₄ , Al ₂ (S
O ₄ ) ₃ , Ti (SO ₄ ) ₂ and Mg (H ₂ PO ₄ ) ₂ are used.
When the metal salt is used, the effect of ionization of the chitosan by ammonium chloride described above is added to the membrane performance by the acid generated by the metathesis of the salt.

As the counter anion of the metal-coordinated chitosan, an anion generated from an inorganic acid such as sulfuric acid, nitric acid, phosphoric acid or hydrohalic acid, or an anion generated from an organic acid such as acetic acid is used.

In order to coordinate the above-mentioned metal ions to the chitosan-based polysaccharide film, for example, the chitosan-based polysaccharide film may be dipped in a solution containing the above metal salt.

Next, the alginic acid-based polysaccharide, which is a typical example of the anionic polysaccharide-based film, will be described. Alginic acid-based polysaccharides refer to alginic acid and its derivatives.Since such alginic acid-based polysaccharides form salts with alkalis such as sodium hydroxide and potassium hydroxide, and easily dissolve in water, this alginate-based polysaccharide By casting the solution on a glass plate and naturally drying it, a transparent and homogeneous alginate film can be formed.
Further, when the alginate solution is brought into contact with a water-soluble organic solvent (for example, ethanol, isopropanol, acetone, etc.) or a concentrated salt solution, the salt has the property of coagulating and precipitating. You can also make it.

When the alginic acid-based polysaccharide membrane is ionized, examples of the ions used as counter cations include the above-mentioned metal ions, ammonium ions, polyamines, and ammonium ions produced from amines having a heterocyclic structure. When ionizing, a plurality of types of counter cations may be used at the same time. As the ion source, salts or hydroxides are used in the case of metal ions, and salts or amines are used in the case of ammonium ions. In order to prepare an ionized alginic acid-based polysaccharide membrane having these cations as counter cations, for example, the alginic acid-based polysaccharide membrane may be immersed in a solution containing the cations for ion exchange.

The content of the counter anion or counter cation in the ionized polysaccharide-based membrane used in the present invention depends on the type of counter anion or counter cation and the gas mixture to be separated. It is selected as appropriate.

Cationic and anionic ionized polysaccharide-based membranes are hydrophilic, and when a gas mixture having a high water vapor content is dehumidified using the membrane, condensation occurs due to a change in temperature, and the membrane is dissolved by the produced water. In some cases, it is desirable to improve the water resistance of the film.

Acids used in forming ammonium salts of chitosan-based polysaccharide membranes include sulfuric acid, phosphoric acid, oxalic acid, malonic acid, succinic acid, maleic acid, fumaric acid, glutaric acid, phthalic acid, terephthalic acid, isophthalic acid, trimellitate. In the case of a polybasic acid such as an acid, trimesic acid, citric acid, aconitic acid, sulfobenzoic acid, pyromellitic acid, and ethylenediaminetetraacetic acid, ionic crosslinking occurs at the same time as ionization to improve water resistance. Similarly, when a metal complex salt is introduced into the chitosan-based polysaccharide membrane and ionized, coordination crosslinking occurs between the polyvalent metal ion and the amino group of chitosan, and water resistance is the same as when treated with a polybasic acid. Will improve.

In the cross-linking method of the ionized chitosan-based polysaccharide film, other than the above, a method of forming an ester bond or an amide bond between molecules of the polysaccharide by an organic polybasic acid, an aldehyde or the like is used to form an acetal bond between the molecules. There are ways. Examples of the cross-linking method using an ester bond or an amide bond include acid chloride of polybasic acid or esterification or amidation of a hydroxyl group or amino group of a cationic polysaccharide with an acid anhydride to introduce a cross-linking structure, and then a monobasic acid or polybasic acid. An ionized chitosan-based polysaccharide-based membrane can be obtained by treating with a basic acid. As the acid chloride and acid anhydride of polybasic acid, the acid chloride and acid anhydride of polybasic acid described above are used. As a cross-linking method by an acetal bond, a chitosan-based polysaccharide film is immersed in a solution to which an acid has been added to form an ionized chitosan-based polysaccharide film, and then the salt film is immersed in an acidic solution of an aldehyde to form an acetal cross-linked structure. There is a way to make. Examples of the aldehyde that can be used here include formaldehyde, acetaldehyde, oxalaldehyde, and glutaraldehyde. A plurality of types of crosslinks such as ionic crosslinks, covalent crosslinks, and coordinate crosslinks can be freely contained in the ionized film.

Further, in the ionization of the alginate-based polysaccharide film, the counter cation is calcium, strontium, alkaline earth metal such as barium, titanium, chromium, manganese, iron, cobalt, nickel, copper, zinc, silver, zirconium, europium, cerium. When at least one metal ion of a transition metal such as rhodium and a metal belonging to Group 3B and 4B of the periodic table such as aluminum and tin is used, cross-linking occurs together with ionization, so that the water resistance of the film is improved. .
In addition to the above-mentioned metal ions, organic polybasic acid or polyhydric alcohol may be used to form an ester bond between the molecules of the polysaccharide, or a method to form an acetal bond between the molecules using an aldehyde or the like. Good.

Next, in order to introduce a cationic group into the cellulose derivative membrane, for example, after the hydroxyl group of cellulose is tosylated with tosyl chloride, it is reacted with a nucleophile such as an amine to form a cationic group. Can be introduced. Similarly, the introduction of an anionic group can be easily obtained by a known method. For example, in the case of carboxymethyl cellulose, chloroacetic acid can be easily obtained by reacting it with cellulose under alkaline conditions, and cellulose sulfate can be easily obtained by reacting chlorosulfonic acid-pyridine mixture with cellulose. The cationic cellulose derivative and the anionic cellulose derivative thus obtained can be ionized in the same manner as the above-mentioned ionization of the chitosan-based polysaccharide and the alginic acid-based polysaccharide. The same method can be used for the crosslinking method.

The shape of the ionized polysaccharide-based membrane used in the method of the present invention is
It may be a flat membrane (flat membrane), a cylindrical membrane, or a hollow fiber membrane, but a hollow fiber membrane that can increase the membrane surface area and thus can downsize the device is industrially advantageous.

As for the thickness of the ionized polysaccharide-based film, the thinner it is, the higher the dehumidification rate will be, but if it is too thin, the strength of the film will be insufficient and the durability will tend to be inadequate, so practically 0.05 to 300 μm.
(Preferably 0.1 to 100 μm). The ionized polysaccharide-based membrane may be used alone, but it is preferable to use it by forming a thin layer of the membrane on the surface of a support membrane, for example, a microporous membrane, because the durability is further improved.

In the method of the present invention, the inorganic gas containing water vapor is brought into contact with the above-mentioned ionized polysaccharide-based membrane, and the water vapor in the inorganic gas is removed, but on the other hand, a wet gas can be obtained. It is also possible to humidify using moist gas. In performing such a dehumidifying / humidifying method, as a method of producing a water vapor partial pressure difference which is a driving force for dehumidifying / humidifying, a side to which an inorganic gas containing water vapor, that is, a to-be-humidified gas is supplied is heated to atmospheric pressure or higher. The side where the water vapor permeates, the so-called permeation side is atmospheric pressure, the supply side is pressurized and the permeation side is depressurized, the supply side is atmospheric pressure and the permeation side is depressurized, the supply side Is kept at atmospheric pressure and the permeate side is kept at a vapor pressure lower than that on the supply side by flowing a gas mixture having a smaller vapor content than that on the supply side.

〔Example〕

Next, the present invention will be described in more detail with reference to Examples, but the present invention is not limited thereto.

Example 1 1 g of chitosan (manufactured by Katoyoshi Co., Ltd., 195 CPS) having a deacetylation degree of 100 mol% and 1 g of acetic acid were dissolved in water to prepare a 1 wt% chitosan / acetate aqueous solution. The aqueous solution was cast on a glass plate and air-dried to obtain a chitosan / acetate membrane (thickness: 20 to 25 μm). The membrane was mixed with ethanol / water containing 1.5 times the molar amount of sulfuric acid with respect to chitosan acetate (5
(0/50 weight ratio) The mixture was immersed in a mixed solution at room temperature for 24 hours and air-dried to obtain a chitosan / sulfate membrane having an ionic crosslinked structure.

The membrane has an effective membrane area provided with an inlet for the dehumidified gas and an outlet for the dehumidified gas on one side (primary side) of the membrane and a vacuum pump on the other side (permeate side) of the membrane. Was attached to a dehumidifying / humidifying device of 28.3 cm ² .

The pressure on the primary side was set to 4 kg / cm ² G and the pressure on the permeate side was set to 1.0 mmHg by operating the vacuum pump. Temperature 25 ° C, relative humidity 100
% Air was continuously supplied at 182 ml / min, and air having a temperature of 25 ° C. and a relative humidity of 18.5% was continuously obtained at 181 ml / min from the dehumidified air outlet.

Example 2 1 g of sodium alginate (manufactured by Hanai Chemical Co., Ltd., 1000 cps) was dissolved in water to prepare a 1% by weight aqueous solution, and a homogeneous transparent sodium alginate film (thickness: 20 to 20) was prepared in the same manner as in Example 1.
25 μm) was obtained. The membrane against sodium alginate
It was immersed in an ethanol / water (50/50 weight ratio) mixed solution containing 1.5 times the molar amount of calcium acetate at room temperature for 24 hours and air-dried to obtain a calcium alginate film having an ionic crosslinked structure.

The membrane was attached to the dehumidifying / humidifying device used in Example 1, the pressure on the primary side was set to 4 kg / cm ² G, the pressure on the permeate side was set to 1.0 mmHg, and the temperature was 25 ° C. and the relative humidity was 100%. Was continuously supplied at a rate of 182 ml / min, the temperature from the dehumidified air outlet was
Air at 25 ° C and relative humidity of 12.5% was continuously obtained at 179 ml / min.

Example 3 1 g of carboxymethylcellulose sodium salt (Serogen 4H, manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) was dissolved in water to prepare a 1% by weight aqueous solution, and a carboxymethylcellulose sodium salt film ( A thickness of 20-25 μm) was obtained.

The membrane was attached to the dehumidifying / humidifying device used in Example 1, the pressure on the primary side was set to ² kg / cm ² G, the pressure on the permeate side was set to 1 mmHg, and the temperature was 20 ° C. and the relative humidity was 100%. When continuously supplied at a rate of 20 / min, the temperature of the dehumidified air is 20
Air at ℃ and relative humidity of 17.2% was continuously obtained at 178 ml / min.

Example 4 A cellulose membrane (manufactured by Union Carbide Co.) was immersed in 1 kg of a 25% sodium hydroxide aqueous solution for 24 hours, then the cellulose membrane was taken out and excess alkali adhering to the membrane was wiped off with paper to obtain an alkali cellulose membrane. It was The alkali cellulose membrane was immersed in 500 g of benzene in which 60 g of paraltoluenesulfonic acid (tosyl) chloride was dissolved at room temperature for 24 hours to obtain a tosylated cellulose membrane. Next, the tosylated cellulose membrane was immersed in 200 ml of dimethylformamide in which 20 g of ethylenediamine was dissolved at 70 ° C. for 48 hours in a nitrogen atmosphere to carry out an amination reaction. The aminated cellulose membrane obtained was immersed in 200 g of a 3% aqueous sodium hydroxide solution,
Hydrolyze unreacted tosyl groups by treating at 70 ° C for 2 hours,
An aminated cellulose membrane (thickness 35 μm) was obtained. The aminated cellulose membrane was immersed in 200 g of a mixed solution of ethanol / water (50/50 weight ratio) having a sulfuric acid concentration of 1.5 × 10 ⁻³ mol / kg at 30 ° C. for 13 hours and air-dried to form an ionized cellulose derivative salt membrane. Obtained.

The membrane was attached to the dehumidifying / humidifying device used in Example 1, the pressure on the primary side was set to 7 kg / cm ² G, the pressure on the permeate side was set to 1 mmHg, and the temperature was 30 ° C. and the relative humidity was 100%. When continuously supplied at a rate of 30 minutes, the temperature of the dehumidified air outlet was 30
Air of 22.4% relative humidity at 184 ml / min was continuously obtained.

Example 5 The chitosan / sulfate membrane produced in Example 1 is provided with an inlet for dehumidified gas and an outlet for dehumidified gas on the primary side of the membrane and lower than the dehumidified gas on the permeate side of the membrane. It was attached to a dehumidifying / humidifying device having an effective membrane area of 28.3 cm ² equipped with a gas inlet having a water vapor pressure and a humidified gas outlet.

Air with a pressure of 7 kg / cm ² G, a temperature of 25 ° C, and a relative humidity of 100% was continuously supplied to the primary side at 180 ml / min, and at the same time, the permeate side was under atmospheric pressure at a temperature of 25 ° C and a relative humidity of 2%. Of air was continuously supplied at 40 ml / min.

From the dehumidified air outlet on the primary side, air with a temperature of 25 ° C and a relative humidity of 16% was continuously obtained at 175 ml / min, and the humidified temperature was 25 ° C from the air outlet on the permeate side. , Relative humidity
58% air was obtained continuously at 45 ml / min.

Comparative Examples 1 to 3 Brown, Cieldron, Cologne, Translated by Yoshio Iwakura “Polymer Chemistry Experimental Method” (Showa 43-5-20) Asakura Shoten 1 g of diacetyl cellulose synthesized by using Experimental Example 505 of p214 was dissolved in acetone. A 1% by weight aqueous acetone solution was prepared, and a diacetyl cellulose membrane (thickness 20 to 25 μm) was obtained in the same manner as in Example 1.

The membrane was attached to the dehumidifying / humidifying device used in Example 1, the pressure on the permeate side was kept constant at 1.0 mmHg, and the pressure on the primary side, the temperature and the supply amount of the supply air were changed, and the relative amount of the dehumidified air was changed. The results of measurement of humidity and amount are shown in Table 1.

From the results of the above Examples and Comparative Examples, it is clear that the method of the present invention is a dehumidifying / humidifying method excellent in moisture permeability.

〔The invention's effect〕

The dehumidification / humidification method using a polymer membrane composed of a polysaccharide-based polymeric substance having an ionized ionic group of the present invention has a higher permeation rate than the conventional method, and an inorganic substance containing water vapor efficiently. The gas can be treated.

Therefore, according to the dehumidifying / humidifying method of the present invention, the dehumidifying / humidifying system can be downsized, the processing capacity can be increased, and the cost can be reduced.
The dehumidification / humidification can be carried out industrially advantageously, and the industrial utility is extremely large.

Claims (5)

[Claims] 1. A polymer film composed of a polysaccharide polymer substance having an ionized ionic group when an inorganic gas containing water vapor is brought into contact with the film to separate the water vapor in the inorganic gas. A dehumidifying / humidifying method characterized by using. 2. The dehumidifying / humidifying method according to claim 1, wherein the polymer substance is a cationic polysaccharide salt. 3. The dehumidifying / humidifying method according to claim 2, wherein the cationic polysaccharide salt is a chitosan salt, a chitosan derivative salt or a cationic cellulose derivative salt. 4. The dehumidifying / humidifying method according to claim 1, wherein the polymer substance is an anionic polysaccharide salt. 5. The dehumidifying / humidifying method according to claim 4, wherein the anionic polysaccharide salt is an alginic acid salt, an alginic acid derivative salt or an anionic cellulose derivative salt.