KR102044876B1 - Water adsorption / desorption material capable of autonomous humidity control and the manufacturing method thereof - Google Patents

Abstract

The present invention relates to a moisture absorption / desorption material and a manufacturing method thereof that can control the indoor humidity, more specifically activated carbon; And a hydrophilic group introduced into the pore surface of the activated carbon, wherein the hydrophilic group includes a hydrophilic group (-COOM) in which a hydrogen cation of a carbonyl group and a carboxy group is substituted with a metal cation. It relates to a adsorption / desorption material and a method for producing the same.

Description

Water adsorption / desorption material with adjustable indoor humidity and its manufacturing method {WATER ADSORPTION / DESORPTION MATERIAL CAPABLE OF AUTONOMOUS HUMIDITY CONTROL AND THE MANUFACTURING METHOD THEREOF}

The present invention relates to a moisture adsorption / desorption material capable of controlling indoor humidity and a method for manufacturing the same, and more specifically, using an activated carbon-based moisture adsorbent to adsorb moisture in a high humidity environment, and to control the humidity in a low humidity environment. It relates to a possible moisture adsorption / desorption material and a method for producing the same.

As the level of culture improves in modern times, the demand for technology that improves the quality of the indoor environment is increasing. Among the factors that determine the most optimal indoor living environment for humankind, it is very important to maintain a constant humidity in the indoor space where the outside air is blocked. The American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE) reported that {ASHRAE. Ventilation for Acceptable Indoor Air Quality (ANSI / ASHRAE Standard 62.1-2010); American Society of Heating, Refrigerating, and Air Conditioning Engineers: Atlanta, GA, 2010}, 30%-60% relative humidity (RH) range is the best relative humidity for human survival, more precisely 40%-60% RH Range. Relative humidity (RH) is the ratio of the amount of water vapor currently included and the amount of water vapor (saturated water vapor) that air can contain at the maximum.

At relative humidity below 40% RH, the incidence of ozone generation and respiratory diseases is high, and the relative humidity above 60% RH increases the growth rate of bacteria and fungi. Given the above conditions affecting the survival of humanity, it is most desirable that the room humidity be maintained in the range of 40%-60% RH. Therefore, it is necessary to develop a moisture adsorbent that provides moisture to indoor air at a relative humidity of less than 40% RH, and to automatically control indoor humidity by absorbing moisture in indoor air at a relative humidity of 60% RH or more.

Activated carbon, a microporous material composed of a carbon skeleton, has a large micropore volume, is easy to mass-produce, and has a low production cost, and thus has been widely applied to the separation and collection of various gases. However, in spite of having micro pores due to the hydrophobic nature of carbon, capillary condensation of water occurs at relatively high relative humidity (> 80% RH), and thus is difficult to use as a water absorbent by itself.

The present invention is to solve the above-mentioned problems, an object of the present invention, the moisture absorption / desorption material capable of controlling the indoor humidity to adsorb moisture in a high humidity environment using a activated carbon-based moisture adsorbent, and desorb moisture in a low humidity environment and It is to provide a preparation method thereof.

However, the problem to be solved by the present invention is not limited to those mentioned above, and other problems not mentioned will be clearly understood by those skilled in the art from the following description.

In accordance with an embodiment of the present invention, the moisture absorbing / desorbing material capable of controlling indoor humidity may include activated carbon; And a hydrophilic group introduced to the pore surface of the activated carbon, wherein the hydrophilic group includes a hydrophilic group (-COOM) in which a hydrogen cation of a carbonyl group and a carboxyl group is substituted with a metal cation.

According to one aspect, the metal cation may be an alkali metal cation, an alkaline earth metal cation or a combination of the two.

According to one aspect, it may be one containing pores of 2 nm or less.

According to one aspect, it may have a porosity of 0.1 cc / g to 5 cc / g.

According to one aspect, it may be 1 to 30% by weight of oxygen atoms.

According to one aspect, it may be 1 to 20% by weight of the metal cation.

According to one aspect, the moisture is adsorbed to the pores in the relative humidity conditions of 60% or more, the moisture may be desorbed from the pores in the relative humidity conditions of 40% or less.

Method for producing a moisture absorbent / desorbable material capable of controlling indoor humidity according to an embodiment of the present invention, the step of introducing a carbonyl group, carboxyl group or both in the pores of the activated carbon; And replacing the hydrogen cation present in the carbonyl group, the carboxyl group, or both with a metal cation through an ion exchange treatment.

According to one aspect, the step of introducing a carbonyl group, carboxyl group or both in the pores of the activated carbon; may include the step of preparing a mixture by injecting the activated carbon in an acidic aqueous solution and heating the mixture.

According to one aspect, the acidic aqueous solution may be at least one selected from the group consisting of nitric acid, sulfuric acid, hydrochloric acid, acetic acid and formic acid.

According to one aspect, the carbonyl group through the ion exchange treatment. Substituting the hydrogen cation present in the carboxyl group or both with a metal cation; preparing a solution in which metal ions are dissolved and activated carbon into which the carbonyl group, the carboxyl group, or both are introduced into the solution in which the metal ions are dissolved It may be to include the step of washing.

According to one aspect, the solution in which the metal ions are dissolved is an aqueous sodium hydroxide solution, potassium hydroxide solution, lithium hydroxide solution, cesium hydroxide solution, beryllium hydroxide solution, magnesium hydroxide solution, calcium hydroxide solution, strontium hydroxide solution and barium hydroxide solution It may include at least one selected from the group consisting of.

The activated carbon-based water adsorption / desorption agent having improved hydrophilicity according to the present invention is an activated carbon moisture adsorption / desorption agent having surface hydrophilicity enhanced through oxidation and ion exchange treatment, and absorbs moisture in a high humidity environment and moisture in a low humidity environment. It has a function of adjusting the humidity of the room to be detached. More specifically, in order to realize the optimum indoor humidity of 40% to 60% RH, the indoor humidity is lowered by moisture adsorption at a relative humidity of 60% RH or higher, and the moisture is desorbed at a relative humidity of 40% RH or lower. To increase the room humidity automatically. The moisture adsorption / desorption material has a very good water adsorption performance at 60% RH or more and a very good desorption performance at 40% RH or less, so that the moisture control performance per unit mass or unit volume is excellent.

In addition, the moisture adsorption / desorption material that can control the indoor humidity according to the present invention is easy to mass-produce because the manufacturing method is simple, low cost, easy to mass-produced activated carbon-based material with excellent hydrothermal stability, so high long-term stability in the adsorption and desorption of repeated moisture see.

1 is a graph showing the moisture adsorption and desorption isotherm of the moisture adsorption / desorption material capable of controlling indoor humidity manufactured according to an embodiment of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. In describing the present invention, when it is determined that detailed descriptions of related known functions or configurations may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted. In addition, terms used in the present specification are terms used to properly express preferred embodiments of the present invention, which may vary depending on the intention of a user, an operator, or customs in the field to which the present invention belongs. Therefore, the definitions of the terms should be made based on the contents throughout the specification. Like reference numerals in the drawings denote like elements.

Throughout the specification, when a member is located "on" another member, this includes not only when one member is in contact with another member but also when another member is present between the two members.

Throughout the specification, when a part is said to "include" a certain component, it means that it may further include other components, not to exclude other components.

Hereinafter, with reference to the embodiments and drawings with respect to the moisture absorption / desorption material capable of controlling the indoor humidity of the present invention will be described in detail. However, the present invention is not limited to these embodiments and drawings.

In accordance with an embodiment of the present invention, the moisture absorbing / desorbing material capable of controlling indoor humidity may include activated carbon; And a hydrophilic group introduced to the pore surface of the activated carbon, wherein the hydrophilic group includes a hydrophilic group (-COOM) in which a hydrogen cation of a carbonyl group and a carboxyl group is substituted with a metal cation.

The activated carbon-based water adsorption / desorption agent having improved hydrophilicity according to the present invention is introduced into a pore surface of activated carbon by introducing a hydrophilic group including a carbonyl group and a hydrophilic group (-COOM) in which a hydrogen cation of a carboxy group is substituted with a metal cation. Equipped with the moisture, in a low humidity environment may have an automatic control function of the indoor humidity to desorb the moisture.

According to one aspect, the metal cation (M) may be an alkali metal cation, alkaline earth metal cation or a combination of both.

According to one aspect, the alkali metal cation is selected from the group consisting of lithium cation (Li ⁺ ), sodium cation (Na ⁺ ), potassium cation (K ⁺ ), rubidium cation (Rb ⁺ ) and cesium cation (Cs ⁺ ) It may be to include at least one.

According to one aspect, the alkaline earth metal cation, or beryllium cation (Be ²⁺ ), magnesium cation (Mg ²⁺ ), calcium cation (Ca ²⁺ ), strontium cation (Sr ²⁺ ) and barium cation (Ba ²⁺ It may include at least one selected from the group consisting of.

The hydrogen cation (H ⁺ ) of the carboxy group (—COOH) is substituted with the metal cation described above and introduced into the pore surface of the activated carbon. For example, (-COONa) in which the hydrogen cation of the carboxyl group is replaced with sodium cation (Na ⁺ ) may be introduced to the pore surface of the activated carbon. Through such ion exchange, the activated carbon-based water adsorption / desorption agent of the present invention has improved surface hydrophilicity.

According to one aspect, the hydrophilic activated carbon-based water adsorption / desorption agent may be to include pores of 2 nm or less. The hydrophilic activated carbon-based water adsorption / desorption agent according to the present invention is a microporous material having a pore size of 2 nm or less, and when the pore size exceeds 2 nm, the water adsorption is much higher than the relative humidity of 60% RH. The problem of moisture adsorption in the humidity section may occur.

According to one aspect, the hydrophilic activated carbon-based water adsorption / desorption agent may have a porosity of 0.1 cc / g to 5 cc / g. If the porosity of less than 0.1 cc / g has a small moisture adsorption performance, there is a problem that less absorption control effect may occur, if the porosity of more than 5 cc / g has a very small density of adsorption / desorbent or structure There may be a problem of poor stability.

According to one aspect, the hydrophilic activated carbon-based water adsorption / desorption agent may be to include 1 to 30% by weight of oxygen atoms. Preferably, it may include 1 wt% to 20 wt% of oxygen atoms or 10 wt% to 30 wt%, and more preferably, 10 wt% to 20 wt% of oxygen atoms. .

If the oxygen atom is less than 1% by weight, the metal cation is substituted so little that it is difficult to effectively increase the hydrophilicity of the moisture adsorbent / desorption material, which may cause the problem of moisture adsorption in the humidity range much higher than the relative humidity of 60% RH. In addition, when the oxygen atom is included in an amount of more than 30% by weight, the structural stability of the adsorption / desorption material may be greatly decreased.

According to one aspect, it may be 1 to 20% by weight of the metal cation. Preferably, it may include 1 wt% to 15 wt% of the metal cation, or may include 5 wt% to 20 wt%, and more preferably, 5 wt% to 15 wt% of the metal cation. have.

If the metal cation is included in less than 1% by weight, it is difficult to effectively increase the hydrophilicity of the water adsorption / desorption material, which may cause the problem of moisture adsorption in the humidity range much higher than the relative humidity of 60% RH. If included, the structural stability of the adsorption / desorption material may be greatly reduced.

According to one aspect, the moisture is adsorbed to the pores in the relative humidity conditions of 60% or more, the moisture may be desorbed from the pores in the relative humidity conditions of 40% or less.

Among the factors that determine the most optimal indoor living environment for humankind, it is very important to maintain a constant humidity in the indoor space where external air is blocked, and at a relative humidity below 40% RH, ozone generation, respiratory tract The incidence of disease is high, and the relative humidity of 60% RH or higher increases the growth rate of bacteria and fungi. Given the above conditions affecting human survival, it is most desirable that the room humidity be maintained in the range of 40% to 60% RH.

According to the present invention, the moisture absorbing / desorbing material capable of controlling indoor humidity is characterized by the introduction of a hydrophilic group including a hydrophilic group (-COOM) in which a hydrogen cation of a carbonyl group and a carboxyl group is substituted with a metal cation on the surface of activated carbon. Capillary condensation occurs, and the desorption of moisture occurs at 40% RH due to the pore structure peculiar to activated carbon.

Due to the characteristics of the hysteresis loop between 40% RH and 60% RH relative humidity, when indoor relative humidity is 40% RH or less, desorption of water occurs to increase the relative humidity in the indoor air, and 60% RH or more. At relative humidity, it has a function of controlling indoor humidity to absorb moisture to lower humidity. Therefore, the moisture absorption / desorption material capable of adjusting the indoor humidity according to the present invention has an automatic indoor humidity control function that maintains an optimum indoor humidity range of 40% RH to 60% RH relative humidity. In addition, the moisture adsorption / desorption material has a very good moisture adsorption performance at 60% RH or more and excellent desorption performance at 40% RH or less, so that the humidity control performance per unit mass or unit volume is excellent.

Method for producing a moisture absorbent / desorbable material capable of controlling indoor humidity according to an embodiment of the present invention, the step of introducing a carbonyl group, carboxyl group or both in the pores of the activated carbon; And replacing the hydrogen cation present in the carbonyl group, the carboxyl group, or both with a metal cation through an ion exchange treatment.

Moisture adsorption / desorption material that can control the indoor humidity according to the present invention is a simple manufacturing method and low cost, easy to mass production, activated carbon-based material with excellent hydrothermal stability, showing high long-term stability when the adsorption and desorption of repeated moisture.

According to one aspect, the step of introducing a carbonyl group, carboxyl group or both in the pores of the activated carbon; may include the step of preparing a mixture by injecting the activated carbon in an acidic aqueous solution and heating the mixture.

According to one aspect, the acidic aqueous solution may be at least one selected from the group consisting of nitric acid, sulfuric acid, hydrochloric acid, acetic acid and formic acid.

For example, activated carbon may be added to an aqueous nitric acid solution, and oxidation may be performed for 20 hours to 30 hours in an oven at 100 ° C. to 150 ° C.

According to one aspect, the carbonyl group through the ion exchange treatment. Substituting the hydrogen cation present in the carboxyl group or both with a metal cation; preparing a solution in which metal ions are dissolved and activated carbon into which the carbonyl group, the carboxyl group, or both are introduced into the solution in which the metal ions are dissolved It may be to include the step of washing.

According to one aspect, the solution in which the metal ions are dissolved is an aqueous sodium hydroxide solution, potassium hydroxide solution, lithium hydroxide solution, cesium hydroxide solution, beryllium hydroxide solution, magnesium hydroxide solution, calcium hydroxide solution, strontium hydroxide solution and barium hydroxide solution It may include at least one selected from the group consisting of.

For example, after neutralizing the activated carbon subjected to the oxidation treatment, and washing with sodium hydroxide solution, the carbonyl group through the ion exchange treatment. It may be to perform the step of replacing the hydrogen cation present in the carboxy group or both with a metal cation.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples.

However, the following examples are only for illustrating the present invention, and the contents of the present invention are not limited to the following examples.

Example

Prior to the surface modification of the activated carbon, 12 hours of pretreatment was performed in a vacuum oven at 100 ° C. to remove moisture and various gases adsorbed on the surface of the activated carbon. 5 g of the pretreated carbon was added to a Teflon reactor containing 50 mL of 1 M nitric acid (HNO ₃ ) aqueous solution, and oxidation was performed for 24 hours in an oven at 130 ° C. After the high temperature treatment, the reactor was cooled to room temperature, and the mixture containing activated carbon was diluted with 1 L of distilled water. The diluted mixture was filtered and washed with distilled water until the filtered solution became neutral. Ion exchange to replace hydrogen cation (H +) present in the carboxyl group (-COH) on the surface of activated carbon with sodium cation (Na +) in order to give stronger hydrophilicity to the modified activated carbon. Treatment proceeded. The ion exchange treatment was completed by washing the filtered activated carbon with 1 L of 1 M sodium hydroxide (NaOH) aqueous solution after the above procedure, and the activated carbon-based water absorbent / desorbent was prepared by drying the collected activated carbon at 100 ° C.

1 is a graph showing the moisture adsorption and desorption isotherm of the moisture adsorption / desorption material capable of controlling indoor humidity manufactured according to an embodiment of the present invention.

In more detail, after activating the surface of the adsorbent by vacuum treatment at 100 ℃ for 12 hours to remove the adsorbed species adsorbed in the pores of the activated carbon-based water adsorption / desorbent prepared in accordance with the embodiment, using a volumetric adsorption equipment Water adsorption and desorption behavior was measured at 25 ° C. according to the relative water pressure (P / P ₀ ).

In general, activated carbon has a strong hydrophobic surface, so that capillary condensation of water occurs at P / P ₀ = 0.8 or more. On the other hand, in the case of the adsorption / desorption material according to the embodiment of the present invention in which a plurality of hydrophilic functional groups such as -COONa are present on the surface through the oxidation ion exchange treatment, the relative pressure (P / P ₀ ) in which capillary condensation occurs is pulled to 0.6 It can be seen that moisture desorption starts at 0.4, relative pressure (P / P ₀ ) and draws a hysteresis loop in the relative pressure range of 0.4 <P / P ₀ <0.6.

That is, the moisture adsorption / desorption material capable of controlling indoor humidity according to the present invention is optimized by introducing a hydrophilic group including a hydrophilic group (-COOM) in which a hydrogen cation of a carbonyl group and a carboxyl group is substituted with a metal cation to an activated carbon pore surface. It has an automatic room humidity control function to maintain a humidity range of 40% RH to 60% RH relative humidity.

Although the embodiments have been described by the limited embodiments and the drawings as described above, various modifications and variations are possible to those skilled in the art from the above description. For example, the techniques described may be performed in a different order than the described method, and / or the components described may be combined or combined in a different form than the described method, or replaced or substituted by other components or equivalents. Appropriate results can be achieved. Therefore, other implementations, other embodiments, and equivalents to the claims are within the scope of the claims that follow.

Claims (12)

Activated carbon; And
It includes; hydrophilic group introduced to the pore surface of the activated carbon,
The hydrophilic group includes a hydrophilic group (-COOM) in which a hydrogen cation of a carbonyl group and a carboxy group is substituted with a metal cation,
Having a porosity of 0.1 cc / g to 5 cc / g,
1 to 30% by weight of oxygen atoms,
It contains 1 to 20% by weight of the metal cation,
Moisture is adsorbed to the pores at a relative humidity of 60% or more,
When the moisture is desorbed from the pores at 40% or less relative humidity conditions,
Moisture adsorption / desorption material that can control indoor humidity.
The method of claim 1,
The metal cation is an alkali metal cation, alkaline earth metal cation or a combination of the two,
Moisture adsorption / desorption material that can control indoor humidity.
Claim 3 has been abandoned upon payment of a set-up fee. The method of claim 1,
It contains pores of 2 nm or less,
Moisture adsorption / desorption material that can control indoor humidity.
delete delete delete delete Introducing a carbonyl group, a carboxyl group, or both into the pores of the activated carbon; And
Comprising: replacing the hydrogen cation present in the carbonyl group, the carboxyl group or both by a metal cation through an ion exchange treatment;
Claim 1 method of manufacturing a moisture absorbent / desorbable material capable of controlling the indoor humidity.
The method of claim 8,
Introducing a carbonyl group, a carboxyl group, or both into pores of the activated carbon;
Preparing a mixture by adding the activated carbon to an acidic aqueous solution, and
To include heating the mixture,
Method for producing a moisture absorbent / desorbable material that can control the indoor humidity.
Claim 10 has been abandoned upon payment of a setup registration fee. The method of claim 9,
The acidic aqueous solution,
At least one selected from the group consisting of nitric acid, sulfuric acid, hydrochloric acid, acetic acid and formic acid,
Method for producing a moisture absorbent / desorbable material that can control the indoor humidity.
The method of claim 8,
The carbonyl group through the ion exchange treatment. Replacing the hydrogen cation present in the carboxy group or both with a metal cation;
Preparing a solution in which metal ions are dissolved, and
Washing the carbonyl group, the carboxyl group, or the activated carbon into which both of the metal ions are dissolved;
Method for producing a moisture absorbent / desorbable material that can control the indoor humidity.
The method of claim 11,
The solution in which the metal ions are dissolved,
At least one selected from the group consisting of aqueous sodium hydroxide solution, potassium hydroxide solution, lithium hydroxide solution, cesium hydroxide solution, beryllium hydroxide solution, magnesium hydroxide solution, calcium hydroxide solution, strontium hydroxide solution and barium hydroxide solution,
Method for producing a moisture absorbent / desorbable material that can control the indoor humidity.

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