KR20040088762A - Manufacturing method of body capable of adsorbing humidity - Google Patents

Abstract

PURPOSE: To obtain superior dehumidifying effect and superior desorption effect by fixing a dehumidifying material to the surface of which lots of hydroxyl groups are attached as having uniform sized mesopores to the inside of a ceramic support formed in a sheet or honeycomb shape. CONSTITUTION: The method comprises a step of preparing a solution by adding a sodium silicate solution to the surfactant solution, thereby mixing the sodium silicate solution with the surfactant solution after preparing a surfactant solution by putting cationic surfactant and nonionic surfactant into distilled water; a step of fixing a dehumidifying material having mesopores into a ceramic support by heating the solution in the state that pH of the solution is adjusted to pH 10 to 11 by adding acid to the solution after dipping a ceramic support whose structure is reinforced by inorganic binder into the solution after heat treating the solution to 650 deg.C; a step of drying the washed ceramic support at temperature of 100 deg.C or more after washing the dehumidifying material fixed ceramic support with ethanol and distilled water; a dehumidifying material stabilization step of washing the ceramic support with ethanol or acid and drying the washed ceramic support after dipping the dried ceramic support into a sodium chloride aqueous solution; and a step of heat treating the ceramic support at 550 deg.C to form mesoporous material in the dried ceramic support and remove surfactant.

Description

Manufacturing method of dehumidifying element {Manufacturing method of body capable of adsorbing humidity}

The present invention relates to a method for manufacturing a sheet or honeycomb-type dehumidifying element, and more particularly has a mesopore of uniform size and has a uniform size of mesopores, unlike conventional hygroscopics having a small pore size and a small specific surface area. A method for manufacturing a dehumidifying element which forms a mesoporous material having a large number of hydroxyl groups attached thereto, so that a dehumidifying material having a large adsorption amount and easy desorption and having a small amount of water remaining after desorption can be supported in a sheet or honeycomb ceramic carrier will be.

Sheet or honeycomb-shaped dehumidification element manufactured by the present invention can be used for the purpose of reducing the moisture in the air to dry the product low temperature, improve quality and maintenance, humidity control of the production process, etc. It can be used to obtain dry air by reducing moisture in the air in the production process of moisture-sensitive products such as electronics, food and powder drying, or in the field for preventing damage or corrosion by moisture.

Generally known dehumidification techniques can be classified into cooling, compression, adsorption, absorption and the like. In the cooling method, low dew point air cannot be obtained due to condensation on the surface, and the compression type uses air to compress the air, thereby causing excessive power. The adsorption method removes moisture by capillary force and surface tension by using an adsorbent powder such as silica gel and activated carbon, but this method requires energy to increase fan power due to large pressure drop. Absorption method is known to remove the moisture by chemical reaction between the absorbent and lithium water, such as lithium chloride, triethylene glycol, but there is a problem that the absorbent liquid with strong corrosive and toxic during operation is discharged into the air stream.

In order to solve these problems, recently, a technology for saving energy in an air dehumidification process has been developed and put into practical use by using a rotary dehumidifying element obtained by chemically synthesizing lithium chloride, metal silicate, silica sol, and the like as an adsorbent.

The dehumidifying element is a mixture of inorganic fibers, such as glass fibers, ceramic fibers, and organic fibers, such as pulp, to produce a slit, and then supplied to a ceramic sheet manufacturing apparatus, followed by a process such as dehydration and compression, and a ceramic sheet having a thickness of about 0.2 mm. The sheet was made into a cylindrical honeycomb shape in which a plurality of small air passages were formed by alternately overlapping the sheet, which was corrugated at 4.0 mm in bone pitch and 2.0 mm in bone height by an embossing roller, by alternately overlapping the sheet with an adhesive. After heat treatment at 550 ℃ to remove the added pulp and organic binder to improve the properties, the honeycomb is impregnated with silica sol for the purpose of strengthening the honeycomb, and then the honeycomb is lithium chloride, calcium chloride, silica gel, alumina gel. Chemically dehumidifying substances in the form of aqueous solutions or solid powders of activated alumina, zeolite and metal silicates. It is prepared by either synthetic reaction or adhesion.

Since the dehumidification cooling system using the dehumidification element manufactured in this way does not use CFC (fluorinated chlorofluorocarbons) or substitutes, it is possible to design a compact design without causing an environmental problem such as destruction of the ozone layer. As it uses waste heat, city gas or solar heat, it has high energy saving effect. Since it does not use a compressor, it consumes less power and has the advantage of reducing power overload due to cooling in summer.

Many techniques for manufacturing such a dehumidifying element are known, and in US Patent No. 5,683,532, a sheet or honeycomb-shaped ceramic carrier is impregnated with water glass, and then semi-dried, and then it is impregnated with an acid solution such as sulfuric acid or hydrochloric acid, and then the ceramic carrier. After the silica hydrogel is fixed in the inside, and then washed and dried to use the technology as a dehumidification sheet and dehumidifying element.

In addition, in US Patent Nos. 5,505,769 and 4,911,775, a sheet or honeycomb-shaped ceramic carrier is impregnated with water glass, semi-dried, and again impregnated with a metal salt solution containing titanium, aluminum, magnesium, and the like, and a metal silicate as a dehumidifying substance in the ceramic sheet. After fixing the is fixed to use a dehumidification sheet and a dehumidification element is disclosed.

In addition, Japanese Patent No. 63-175619 impregnates a ceramic sheet with water glass, semi-drys it to the extent that the sheet can be corrugated, and then dries the processed corrugated paper and flat paper in an acid solution or a metal salt solution to dehumidify it. The present invention discloses a technique of producing a material, washing, drying, stacking flat paper and corrugated paper, and laminating alternately to fix silica gel or metal silicate on a ceramic sheet to use as a dehumidifying element.

In addition, in Japanese Patent No. 60-175521, the ceramic carrier is impregnated with water glass, semi-dried, and then again impregnated with calcium chloride solution to fix calcium silicate in the ceramic sheet, which is then washed, dried and then again deposited in lithium chloride solution. It discloses a technique for drying and using it as a dehumidification sheet and a dehumidification element.

In addition, US Patent No. 6,187,381, impregnated with a ceramic carrier in an alkali silicate and alkali hydroxide mixed solution and then dried, and reacted with an acid solution to form a silica gel in the ceramic carrier, a metal salt solution containing calcium, magnesium, etc. as necessary The present invention discloses a technique of impregnating a metal silicate in a ceramic sheet and using the same as a dehumidifying sheet and a dehumidifying element.

The above techniques are to form silica gel or metal silicate in a sheet or honeycomb-shaped ceramic carrier and use the same as a dehumidifying element. The dehumidifying material in which micropore or mesopoie is formed in the ceramic carrier is fixed.

However, when the dehumidification element is manufactured by the conventional method as described above, the dehumidification material fixed in the sheet or honeycomb-shaped ceramic carrier may have uneven pore size even though micropore and mesopores coexist or mesopores exist. In addition, there is a disadvantage that the moisture absorption amount is small and the desorption of water is not easy when desorption, so the amount of residual water in the sheet decreases the regeneration efficiency.

Accordingly, the present invention is to solve the above-described problems, the moisture absorption amount by fixing the dehumidifying material having a large number of hydroxyl groups on the surface while having a uniform mesopore in the sheet or honeycomb-shaped ceramic carrier The purpose of the present invention is to provide a method of manufacturing a dehumidifying device having a high regeneration efficiency as well as an excellent dehumidification effect and easy desorption of moisture during regeneration.

1 is a graph showing the results of nitrogen adsorption isotherm of the dehumidifying device prepared according to the present invention.

The present invention to achieve the above object

Preparing a surfactant solution by adding a cationic surfactant and a nonionic surfactant to distilled water, and then adding and mixing a sodium silicate solution to prepare an immersion liquid; After heat treatment at 650 ° C, immersing the ceramic carrier reinforced with inorganic binder, adding acid to the immersion liquid and heating it at a pH of 10 ~ 11 to fix the dehumidifying substance having mesopores in the ceramic carrier. Making a step; Washing the ceramic carrier to which the dehumidifying substance is fixed, with ethanol and distilled water, and then drying at 100 ° C. or higher; A dehumidifying material stabilizing step of supporting the dried ceramic carrier in an aqueous sodium chloride solution and then washing and drying it with ethanol or acid; And forming a mesoporous material in the dried ceramic carrier and performing a heat treatment at 550 ° C. to remove the surfactant.

Hereinafter, the present invention will be described in more detail.

In the present invention, a cationic surfactant and a nonionic surfactant are added to distilled water to prepare a dehumidifying device, and then a surfactant solution is prepared, followed by adding and mixing sodium silicate solution to prepare an immersion solution. .

At this time, the surfactant solution is to act as a structural derivative of the mesoporous material, in the present invention, 126 parts by weight of the cationic surfactant and 21 parts by weight of the nonionic surfactant is added to 1716 parts by weight of distilled water and completely dissolved to cool to room temperature It was prepared by.

The cationic surfactant and the nonionic surfactant may be ones that are commonly used. In the present invention, alkyl trimethylammonium bromide is used as the cationic surfactant, and polyoxyethylene alkyl ether is used as the nonionic surfactant. It was.

As described above, when a cationic surfactant and a nonionic surfactant are added to distilled water and dissolved to prepare a surfactant solution, the present invention adds sodium silicate solution to prepare an immersion liquid.

The sodium silicate aqueous solution may be prepared by a conventional manufacturing method, but in the present invention, the sodium silicate solution prepared by mixing 2325 parts by weight of an aqueous sodium hydroxide solution to 675 parts by weight of colloidal silica was used. Sodium silicate solution thus prepared is represented by the general formula Na ₂ O · nSiO ₂ and n = 2 ~ 4.

When the immersion liquid is prepared, in the present invention, the ceramic carrier is immersed in the immersion liquid, followed by neutralization of an acid to be heated to adjust the pH to 10 to 11, thereby adhering a dehumidifying substance having mesopores in the ceramic carrier. do.

After this step, the dehumidifying substance having mesopores is fixed in the ceramic carrier. At this time, various kinds of acids including acetic acid may be added as an acid for adjusting pH.

As the ceramic carrier, a ceramic sheet manufactured by a conventional method or a honeycomb prepared by post-processing the ceramic sheet may be used having various structures and shapes suitable for the field to be applied. More preferably, it is preferable to use a honeycomb manufactured by using the apparatus shown in Korean Patent No. 347010, which has been patented and registered by the present applicant.

In particular, the sheet or honeycomb-shaped ceramic carrier to be added is preferably heat treated at 650 ° C. to remove internal pulp, organic binder, and the like and then reinforced with an inorganic binder such as silica sol.

The heat treatment of the ceramic carrier is performed at a high temperature in the process of desorbing the moisture contained in the dehumidifying element in order to completely remove organic substances such as pulp and organic binder contained therein and reuse the dehumidifying element in which the adsorption of water is completed. When exposed, there is a risk of catching fire due to organic components. Also, it prevents deterioration of dehumidification performance due to deterioration of organic materials due to long-term use, and improves the strength, durability and chemical resistance of the ceramic carrier itself. To improve

When the dehumidifying material is fixed to the ceramic carrier by carrying out as described above, the ceramic carrier is washed with ethanol and distilled water and then dried at 100 ° C. or higher.

When sufficiently dried, in the present invention, the dried ceramic carrier is immersed in an aqueous sodium chloride solution, and then washed with ethanol or hydrochloric acid and dried to dehumidify the stabilizing material.

After the stabilization step, the dried ceramic carrier is subjected to a heat treatment at 550 ° C. The heat treatment of the ceramic carrier forms a mesoporous material as a dehumidifying substance in the ceramic carrier and removes organic substances such as surfactants. For that.

The dehumidifying device according to the present invention manufactured by heat treatment as described above has a mesopore of uniform size in a ceramic carrier, and a dehumidifying material having many hydroxyl groups attached to the surface thereof is fixed. Therefore, the specific surface area of the dehumidifying material in the manufactured dehumidifying element is high, the amount of moisture absorption is not only excellent dehumidification effect, it is easy to desorption of water during desorption, there is an advantage that the regeneration efficiency is high because the amount of moisture remaining.

The dehumidifying device according to the present invention prepared as described above can be applied to the production process of moisture-sensitive products such as pharmaceuticals, electronics, food, and powder drying, or to the field for preventing damage or corrosion by water, in addition to air It can be used for the purpose of drying the product at low temperature, improving and maintaining the quality, and controlling the humidity of the production process by reducing the moisture in the product.

Hereinafter, the present invention will be described in more detail with reference to the following examples, which are only presented to aid the understanding of the present invention, but the present invention is not limited thereto.

<Examples 1 to 3>

6325 g of colloidal silica was mixed with 2325 g of an aqueous sodium hydroxide solution, followed by heating to prepare a sodium silicate solution (6 wt% SiO ₂ , 2.3 wt% Na ₂ O, 88.7 wt% H ₂ O), separately from the cationic surfactant (brominated 126 g of alkyltrimethylammonium) and 21 g of a nonionic surfactant (polyoxyethylene alkyl ether) were added to 1716 g of distilled water, dissolved completely by heating, and then cooled to room temperature to prepare a surfactant solution. Dipping solution was prepared.

The immersion liquid was immersed in a ceramic carrier heat-treated at a temperature of 650 ℃ and structurally reinforced with silica sol, and the like was added to acetic acid and heated to a pH of 10.0, 10.5, 11.0, and then cooled to room temperature. The dehumidifying material was fixed in the ceramic carrier.

The ceramic carrier to which the dehumidification material is fixed is sufficiently washed with ethanol and distilled water, dried at 100 ° C., and then immersed in sodium chloride solution and washed with distilled water to stabilize the dehumidifying material fixed in the carrier, which is then dried at 100 ° C. After the heat treatment at 550 ℃ to prepare a dehumidifying device according to the present invention.

The specific surface area of the dehumidifying element thus prepared, the fixed amount of the dehumidifying substance fixed to the ceramic carrier, the average pore size and the moisture adsorption amount of the dehumidifying substance were measured and the results are shown in Table 1 below. At this time, the moisture adsorption amount was put in the prepared dehumidifying device in a constant temperature and humidity device and maintained at 35 ℃, 50% relative humidity conditions for 24 hours to measure the adsorption amount.

<Comparative Examples 1 to 3>

187.5g of water glass was mixed with 2315.5ml of distilled water, mixed with a sheet-shaped ceramic carrier, and then the pH was adjusted to 3.5 4.5 and 5.5 by adding 1M sulfuric acid solution, and then taken out to remove sodium sulfate as a byproduct. Repeated washing with an ammonium solution and ethanol to prepare a ceramic carrier fixed to the dehumidifying material. The ceramic carrier to which the dehumidifying material is fixed was dried at 100 ° C. and then heat-treated at 550 ° C. to manufacture a dehumidifying element.

The specific surface area of the dehumidifying element thus prepared, the fixed amount of the dehumidifying substance fixed to the ceramic carrier, the average pore size and the moisture adsorption amount of the dehumidifying substance were measured and the results are shown in Table 1 below. At this time, the moisture adsorption amount was put in the prepared dehumidifying device in a constant temperature and humidity device and maintained at 35 ℃, 50% relative humidity conditions for 24 hours to measure the adsorption amount.

division Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 pH 10.0 10.5 11.0 3.5 4.5 5.5 Specific surface area (kg / ㎥) 487 520 553 399 429 461 Deposition of dehumidifying substance (%) 153.7 162.3 172.9 138.6 141.7 149.2 Average pore size 45 59 72 29 35 53 Water absorption (wt%) 16.2 17.0 17.6 13.7 14.3 14.9

As shown in Table 1, in Examples 1 to 3 of the present invention, the specific surface area and the adhesion amount of the dehumidifying material and the average pore amount were compared with those of the Comparative Examples 1 to 3 of the dehumidifying device manufactured by the conventional method. It can be seen that the size and moisture adsorption amount are excellent.

More specifically, it can be seen that in Examples 1 to 3, as the pH is increased, the specific surface area and pore size increase, and the adhesion amount of the dehumidifying material also increases. In addition, the results of nitrogen adsorption isotherm of the dehumidification device prepared in Example 2 (pH = 10.5) are shown in FIG. 1, and as shown in FIG. 1, rapid adsorption of water at initial partial pressure is achieved, and then adsorption is constant at mesopores. It can be seen that it is a dehumidifying element that has a desorption characteristic that progresses at a speed and shows almost no hysteresis even in the adsorption / desorption curve. In the case of Comparative Examples 1 to 3, the specific surface area and pore size increased as the pH was increased, and the adhesion amount of the dehumidifying material was increased, but the specific surface area, pore size, and moisture adsorption amount were relatively smaller than those of Examples 1 to 3. It can be seen. In particular, in the case of the embodiment of the present invention it can be seen that the water adsorption amount is increased by about 18% compared to the comparative example.

Experimental Example 1

The dehumidifying elements manufactured according to Example 2 and Comparative Example 2 were attached to the outlet side of the self-made dehumidifying apparatus, air was injected, and then the relative humidity at the outlet side was measured.

Inlet temperature (℃) 27 Absolute Humidity of Inlet Air (g / Kg) 18 Absolute Humidity at Exit (g / Kg) Example 2 10.9 Comparative Example 2 11.7

As shown in Table 2, it can be seen that in Example 2 of manufacturing the dehumidifying element at pH 10.5, the dehumidification efficiency was increased by about 12% compared to the case of Comparative Example 2 which prepared the dehumidifying element at pH4.5.

As described above, the present invention provides a dehumidifying effect with a high specific surface area and high moisture absorption rate by allowing dehumidifying substances having a large number of hydroxyl groups to be adhered to the surface while having a uniform mesopor in a sheet or honeycomb-shaped ceramic carrier. It is a useful invention to provide a method for manufacturing a dehumidifying element that is excellent in addition to the easy desorption of moisture and low desorption effect.

Claims (6)

Preparing a surfactant solution by adding a cationic surfactant and a nonionic surfactant to distilled water, and then adding and mixing a sodium silicate solution to prepare an immersion liquid; After heat treatment at 650 ° C, immersing the ceramic carrier reinforced with inorganic binder, adding acid to the immersion liquid and heating it at a pH of 10 ~ 11 to fix the dehumidifying substance having mesopores in the ceramic carrier. Making a step; Washing the ceramic carrier to which the dehumidifying substance is fixed, with ethanol and distilled water, and then drying at 100 ° C. or higher; A dehumidifying material stabilizing step of supporting the dried ceramic carrier in an aqueous sodium chloride solution and then washing and drying it with ethanol or acid; And heat-treating at 550 ° C. to form a mesoporous material in the dried ceramic carrier and to remove the surfactant. The method of claim 1, wherein the immersion liquid is 126g parts by weight of cationic surfactant and 21 parts by weight of nonionic surfactant is added to 1716 parts by weight of distilled water, heated and dissolved completely to cool to room temperature, and then hydrated in 675 parts by weight of colloidal silica in this solution Method for producing a dehumidifying element, characterized in that the prepared by mixing the sodium silicate solution prepared by mixing 2325 parts by weight of an aqueous sodium solution. The method of manufacturing a dehumidifying element according to claim 1 or 2, wherein the ceramic carrier has a ceramic sheet shape. The method of manufacturing a dehumidifying element according to claim 1 or 2, wherein the ceramic carrier has a ceramic honeycomb shape. Dehumidification element, characterized in that manufactured by the manufacturing method of claim 3. A dehumidifying element, which is manufactured by the manufacturing method of claim 4.