JP2021116222A - Method for fixing carbon dioxide, method for producing fixed carbon dioxide, and apparatus for fixing carbon dioxide - Google Patents

Abstract

To provide a novel method for fixing carbon dioxide.SOLUTION: A method for fixing carbon dioxide according to the present invention comprises a contact step and an electrolysis step, in which the contact step further comprises bringing a mixture liquid containing sodium hydroxide and containing at least one of a chloride of a group 2 element and a chloride of a divalent metal element into contact with a gas containing carbon dioxide. The concentration of the sodium hydroxide in the mixture liquid is 0.2 N or less. The electrolysis step comprises electrolyzing the mixture liquid after the contact to form a mixture liquid after electrolysis, reusing the mixture liquid after electrolysis as the mixture in the contact step, and bringing the mixture liquid into contact with the gas in at least one state selected from the group consisting of standing, flowing, shaking, showering and atomizing the mixture liquid.SELECTED DRAWING: Figure 1

Description

The present invention relates to a method for fixing carbon dioxide, a method for producing immobilized carbon dioxide, and a carbon dioxide fixing device.

As a method for fixing carbon dioxide, for example, Patent Document 1 describes a method for producing sodium carbonate by reacting an aqueous solution of sodium hydroxide with combustion exhaust gas containing carbon dioxide. However, a new method for fixing carbon dioxide is required.

Japanese Unexamined Patent Publication No. 6-263433

Therefore, an object of the present invention is to provide a new method for fixing carbon dioxide.

In order to achieve the above object, the method for fixing carbon dioxide of the present invention is:
Including contact process and electrolysis process
The contact step comprises a mixed solution containing at least one of sodium hydroxide and potassium hydroxide, and further containing at least one of a chloride of a Group 2 element and a chloride of a divalent metal element, and carbon dioxide. Contact with the contained gas,
In the electrolysis step, the mixed solution after the contact is electrolyzed to obtain a mixed solution after electrolysis.
In the contacting step, the mixed solution after electrolysis is reused as the mixed solution.

The method for producing immobilized carbon dioxide of the present invention is:
Includes an immobilization step to immobilize carbon dioxide
The immobilization step is carried out by the method for immobilizing carbon dioxide of the present invention.

The carbon dioxide fixing device of the present invention
Includes reaction vessel, carbon dioxide fixative charging means, and gas-liquid mixing means
The carbon dioxide fixative charging means can charge the carbon dioxide fixative into the reaction vessel.
The reaction vessel includes a reaction chamber and an electrolysis chamber.
The reaction chamber can contain a carbon dioxide fixative and
The gas-liquid mixing means can mix a gas containing carbon dioxide with the carbon dioxide fixative contained in the reaction chamber.
The electrolysis chamber includes an anode chamber and a cathode chamber.
Liquids can be sent from the reaction chamber to the electrolysis chamber and from the electrolysis chamber to the reaction chamber, respectively.
In the reaction chamber, the carbon dioxide fixative and carbon dioxide are reacted to each other.
The carbon dioxide fixative after the reaction can be sent from the reaction chamber to the electrolysis chamber.
In the electrolytic chamber, the carbon dioxide fixative after the reaction is electrolyzed and
The carbon dioxide fixative after electrolysis can be sent from the electrolytic chamber to the reaction chamber.
In the reaction chamber, the carbon dioxide fixative after electrolysis can be reused as the carbon dioxide fixative.

According to the present invention, it is possible to provide a new method for fixing carbon dioxide.

FIG. 1 is a schematic cross-sectional view showing an example of the carbon dioxide fixing device of the second embodiment. FIG. 2 is a schematic cross-sectional view showing an example of the carbon dioxide fixing device of the modified example 1. FIG. 3 is a schematic cross-sectional view showing an example of the carbon dioxide fixing device of the modified example 2. FIG. 4 is a schematic cross-sectional view showing an example of the carbon dioxide fixing device of the third embodiment. FIG. 5 is a schematic cross-sectional view showing an example of the carbon dioxide fixing device of the fourth embodiment. FIG. 6 is a diagram showing an electrolyzer according to the first embodiment. FIG. 7 is a photograph of a mixture of a sodium chloride solution and a calcium chloride solution after electrolysis after contact with carbon dioxide in Example 1. FIG. 8 is a diagram showing an electrolyzer in the second embodiment. FIG. 9 is a graph showing the weight of the precipitate formed in the mixed solution due to the contact with carbon dioxide in Example 2. FIG. 10 is a graph showing the carbon dioxide concentration in the container after contact in Example 2. FIG. 11 is a graph showing the carbon dioxide concentration in the container after contact in Example 2. FIG. 12 is a graph showing the weight of calcium carbonate adhered to the air stone in Example 3. FIG. 13 is a photograph of the air stone after contact in Example 4. FIG. 14 is a graph showing the weight of calcium carbonate adhered to the air stone in Example 4. FIG. 15 is a photograph of the mixed solution containing sodium hydroxide and calcium chloride before and after contact with carbon dioxide in Reference Example 1. FIG. 16 is a graph showing the weight of the precipitate formed in the mixed solution due to the contact with carbon dioxide in Reference Example 1. FIG. 17 is a graph showing the weight of the precipitate formed in the mixed solution due to the contact with carbon dioxide in Reference Example 1. FIG. 18 is a photograph of a mixed solution containing sodium hydroxide and calcium chloride in Reference Example 2. FIG. 19 is a graph showing the carbon dioxide concentration in the container after contact in Reference Example 3. FIG. 20 is a diagram showing the shape of the octagonal pillar plastic bottle in Reference Example 3. FIG. 21 is a graph showing the carbon dioxide concentration in the container after contact in Reference Example 3. FIG. 22 is a graph showing the carbon dioxide concentration in the container after contact in Reference Example 3. FIG. 23 is a diagram showing a state in which contact by spraying is performed in Reference Example 4. FIG. 24 is a graph showing the carbon dioxide concentration in the container after contact in Reference Example 4. FIG. 25 is a diagram showing contact means in Reference Example 4. FIG. 26 is a graph showing the carbon dioxide concentration in the container after contact in Reference Example 4. FIG. 27 is a graph showing the weight of the precipitate formed in the mixed solution due to the contact with carbon dioxide in Reference Example 5. FIG. 28 is a graph showing the weight of the precipitate formed in the mixed solution due to the contact with carbon dioxide in Reference Example 5. FIG. 29 is a graph showing the weight of the precipitate formed in the mixed solution due to the contact with carbon dioxide in Reference Example 6. FIG. 30 is a graph showing the weight of the precipitate formed in the mixed solution due to the contact with carbon dioxide in Reference Example 7. FIG. 31 is a diagram showing a state in which contact by shaking is performed in Reference Example 3. FIG. 32 is a graph showing the carbon dioxide concentration in the container after contact in Reference Example 3. FIG. 33 is a diagram showing a state in which contact by bubbling is performed in Reference Example 8. FIG. 34 is a graph showing the weight of the precipitate formed in the mixed solution due to the contact with carbon dioxide in Reference Example 8. FIG. 35 is a schematic view illustrating the form of the pipe in Reference Example 8. FIG. 36 is a graph showing the carbon dioxide concentration in the container after contact in Reference Example 8. FIG. 37 is a graph showing the carbon dioxide concentration in the container after contact in Reference Example 8. FIG. 38 is a graph showing the carbon dioxide concentration in the container after contact in Reference Example 8. FIG. 39 is a graph showing the carbon dioxide concentration in the container after contact in Reference Example 8. FIG. 40 is a graph showing the carbon dioxide concentration in the container after contact in Reference Example 9. FIG. 41 is a diagram showing a state in which contact by bubbling is performed in Reference Example 9. FIG. 42 is a graph showing the carbon dioxide concentration in the container after contact in Reference Example 9. FIG. 43 is a graph showing the carbon dioxide concentration in the container after contact in Reference Example 9. FIG. 44 is a graph showing the weight of the precipitate formed in the mixed solution due to the contact with carbon dioxide in Reference Example 10. FIG. 45 is a graph showing the carbon dioxide concentration in the container after contact in Reference Example 10. FIG. 46 is a graph showing the weight of the precipitate formed in the mixed solution due to the contact with carbon dioxide in Reference Example 11. FIG. 47 is a schematic view showing a carbon dioxide fixing device in Reference Example 12.

In the method for fixing carbon dioxide of the present invention, for example, at least one of the chloride of the Group 2 element and the chloride of the divalent metal element is calcium chloride.

In the method for fixing carbon dioxide of the present invention, for example, in the contacting step, the gas is brought into the mixed solution to bring the mixed solution into contact with the gas.

In the method for fixing carbon dioxide of the present invention, for example, at least one of the sodium hydroxide and potassium hydroxide is sodium hydroxide, and the concentration of the sodium hydroxide in the mixed solution is less than 0.2 N. ..

The method for fixing carbon dioxide of the present invention further includes, for example, a concentration adjusting step, in which the concentration adjusting step detects the pH of the mixed solution, and based on the detected pH, sodium hydroxide in the mixed solution. The concentration of is maintained below 0.2 N.

In the method for fixing carbon dioxide of the present invention, for example, at least one of the sodium hydroxide and potassium hydroxide is sodium hydroxide, and the concentration of the sodium hydroxide in the mixed solution is 0.05 N or more. ..

In the method for fixing carbon dioxide of the present invention, for example, at least one of the chloride of the Group 2 element and the chloride of the divalent metal element is calcium chloride, and the concentration of the calcium chloride in the mixed solution is high. , 0.05 mol / L or more.

In the method for fixing carbon dioxide of the present invention, for example, the temperature of the mixed solution is 70 ° C. or higher.

In the method for fixing carbon dioxide of the present invention, for example, the contact step includes a first contact step and a second contact step, and the first contact step is at least one of sodium hydroxide and potassium hydroxide. The solution containing carbon dioxide and the gas containing carbon dioxide are brought into contact with each other, and in the second contact step, after the first contact step, the solution is subjected to the chloride of the Group 2 element and the divalent metal element. At least one of the chlorides is added, and the electrolysis step is performed after the second contact step with a solution containing at least one of the sodium hydroxide and potassium hydroxide, the chloride of the Group 2 element, and 2. The mixed solution with at least one of the chlorides of valent metal elements is electrolyzed, and in the first contact step, the mixed solution after the electrolysis is used with at least one of the sodium hydroxide and potassium hydroxide. Reuse as a solution containing.

In the carbon dioxide fixing device of the present invention, for example, the gas-liquid mixing means is inserted into the reaction chamber, and a plurality of holes are provided at the insertion end portions, and the plurality of holes are provided to the reaction chamber. The gas can be released into the carbon dioxide fixative.

In the carbon dioxide fixing device of the present invention, for example, the gas-liquid mixing means includes a liquid circulation flow path and a pump, and the liquid circulation flow path includes a liquid suction end portion and a liquid discharge end portion, and the liquid. The suction end is inserted into the electrolytic chamber, the liquid discharge end is inserted into the reaction chamber, and the pump sucks the carbon dioxide fixative from the liquid suction end and sucks the liquid. However, the carbon dioxide fixative can be released from the liquid discharge end.

In the carbon dioxide fixing device of the present invention, for example, the liquid circulation flow path further includes a gas-liquid mixing member, and the gas-liquid mixing member can mix the gas with the liquid flowing through the liquid circulation flow path. be.

In the carbon dioxide fixation device of the present invention, for example, the reaction vessel includes a first reaction vessel and a second reaction vessel, the first reaction vessel includes the reaction chamber, and the second reaction vessel includes the reaction chamber. The electrolytic chamber is included.

In the carbon dioxide fixation device of the present invention, for example, the gas-liquid mixing means is inserted into the reaction chamber, and the insertion end is coated with at least one of a water repellent and an electrically negative material. ..

In the present invention, "fixation of carbon dioxide (also referred to as immobilization)" means, for example, reducing the concentration of carbon dioxide in the gas by removing carbon dioxide from the gas containing carbon dioxide.

An embodiment of the present invention will be described. The present invention is not limited to the following embodiments. In each of the following figures, the same parts are designated by the same reference numerals. Further, the explanations of the respective embodiments can be referred to each other's explanations unless otherwise specified. Further, the configurations of the respective embodiments can be combined unless otherwise specified. Unless otherwise specified, the terms used herein may be used in the meaning commonly used in the art.

[Embodiment 1]
(How to fix carbon dioxide)
The method for fixing carbon dioxide of the present invention includes a contact step and an electrolysis step, and the contact step comprises at least one of sodium hydroxide (NaOH) and potassium hydroxide (KOH), and further, Group 2 A mixed solution containing at least one of an element (alkaline earth metal) chloride and a divalent metal element chloride is _{brought into contact with a gas containing carbon dioxide (CO 2} ), and the electrolysis step is carried out as described above. The mixed solution after contact is electrolyzed to obtain a mixed solution after electrolysis, and the mixed solution after electrolysis is reused as the mixed solution in the contacting step. In the method for fixing carbon dioxide of the present invention, other configurations and conditions are not particularly limited.

Examples of the Group 2 element include beryllium, magnesium, calcium, strontium, barium and radium, and examples thereof include calcium, magnesium, strontium and barium. Examples of the chloride of the Group 2 element include calcium chloride, magnesium chloride, strontium chloride, and barium chloride.

The divalent metal element is not particularly limited, and examples thereof include zinc. Examples of the chloride of the divalent metal element include zinc chloride.

In the following description, the mixed solution contains sodium hydroxide as at least one of sodium hydroxide (NaOH) and potassium hydroxide (KOH), and is used as a chloride of the Group 2 element (alkaline earth metal). , Calcium chloride is included as an example to explain. However, the present invention is not limited to this.

First, the contact process will be described below. In the contact step, a mixture containing sodium hydroxide (NaOH) and further containing calcium chloride (CaCl ₂ ) is brought into contact with a gas containing carbon dioxide (CO _2). In the contact step, other configurations and conditions are not particularly limited.

In the method for fixing carbon dioxide of the present invention, as will be described later, in the electrolysis step, the mixed solution after the contact is electrolyzed to obtain a mixed solution after electrolysis. Then, in the contacting step, the mixed solution after electrolysis is reused as the mixed solution.

According to the method for fixing carbon dioxide of the present invention, by including the contact step, sodium hydroxide and calcium chloride are reacted with carbon dioxide _{to generate calcium carbonate (CaCO 3} ), thereby producing carbon dioxide. Can be fixed. According to the present invention, for example, carbon dioxide can be fixed in a solid state. Thereby, for example, carbon dioxide can be fixed in a more stable state. Also, for example, it becomes easy to handle.

The gas containing carbon dioxide is not particularly limited, and examples thereof include combustion exhaust gas, indoor air, and air.

The concentration of carbon dioxide in the gas containing carbon dioxide is not particularly limited, and is, for example, 0 to 100%. As will be described later, according to the present invention, even low-concentration carbon dioxide can be fixed. Further, since a white precipitate is formed in the mixed solution by bubbling 100% carbon dioxide, the present invention can obtain an effect even in fixing carbon dioxide at a high concentration.

The temperature of the gas containing carbon dioxide is not particularly limited, and may be, for example, a low temperature of 0 ° C. or lower, a general temperature of atmospheric temperature or room temperature, a temperature of less than 100 ° C., and a high temperature of 120 to 200 ° C. The temperature of the gas may be low from the viewpoint of preventing evaporation of water. However, the present invention can be applied, for example, even if the gas containing carbon dioxide has a high heat.

The gas containing carbon dioxide may contain, for example, a substance other than carbon dioxide. Substances other than the carbon dioxide is not particularly limited, for example, SOx, NOx, _{O 2,} dust, and the like. In the present invention, for example, since the mixed solution is basically alkaline, it is considered that a neutralization reaction occurs between the mixed solution and the acidic substance or the like. However, the present invention is not limited to this.

The mixed solution contains sodium hydroxide and calcium chloride as described above. The method for producing the mixed solution is not particularly limited, and examples thereof include low-concentration mixing. The low concentration is, for example, less than 5N as the concentration of sodium hydroxide before mixing. According to the low concentration mixing, for example, the formation of a precipitate of _{calcium hydroxide (Ca (OH) 2) can be prevented.} Specifically, the method for preparing the mixed solution can be prepared by, for example, putting a 0.1 N sodium hydroxide solution and a 0.1 mol / L calcium chloride solution in a container and then mixing them. can.

In the mixed solution, the concentration of the sodium hydroxide is not particularly limited, and is, for example, 0.01 N or more and 0.05 N or more, and 0.2 N or less, less than 0.2 N, and 0.1 N or less. The unit "N" of the concentration indicates the normality, and in the case of sodium hydroxide, 0.01N is 0.01 mol / L. When the concentration of the sodium hydroxide is 0.01 N or more and 0.05 N or more, for example, more carbon dioxide can be fixed. Further, when the concentration of the sodium hydroxide is less than 0.2 N and 0.1 N or less, for example, more carbon dioxide can be fixed.

As shown in Examples described later, when the concentration of sodium hydroxide is 0.2 N or more, calcium hydroxide precipitates due to the reaction between calcium chloride and high-concentration sodium hydroxide at the contact. Therefore, it is considered that the amount of calcium carbonate synthesized by the contact is reduced.

Therefore, for example, the method for fixing carbon dioxide of the present invention further includes a concentration adjusting step, in which the concentration adjusting step detects the pH of the mixed solution, and based on the detected pH, in the mixed solution. The concentration of sodium hydroxide may be maintained at 0.2 N or less. The pH detection can be carried out using known pH detecting means. In the concentration adjusting step, the association between the detected pH and the concentration of sodium hydroxide can be performed by referring to, for example, a value measured in advance. The pre-measured value can be obtained, for example, using a titration curve. Specifically, as an example, when the titration was actually performed, the pH was 13.00 when the concentration of sodium hydroxide was 0.15N, the pH was 13.17 when the concentration was 0.20N, and the pH was 13 when the concentration was 0.25N. It was .26, and in the case of 0.30N, it was pH 13.32. Therefore, based on the result of the titration, it can be determined that the concentration of sodium hydroxide is 0.2 N or less in the concentration adjusting step, for example, when the pH is 13.17 or less. However, this is not limited. The concentration of sodium hydroxide in the mixed solution can be adjusted by adding a sodium hydroxide solution and distilled water to the mixed solution. The sodium hydroxide solution may be, for example, a post-electrolysis mixed solution after the electrolysis step, which will be described later.

On the other hand, in other words, according to the method for fixing carbon dioxide of the present invention, even when the mixed solution contains a high concentration of sodium hydroxide, calcium chloride and the high concentration of sodium hydroxide are contained. It means that it is possible to reduce the concentration of sodium hydroxide in the mixed solution by causing the precipitation of calcium hydroxide by the reaction. Therefore, according to the method for fixing carbon dioxide of the present invention, for example, even when a high concentration (for example, 0.2 N or more) of sodium hydroxide is generated due to high heat, the concentration can be lowered and a harmful gas can be generated. Can be suppressed.

In the mixed solution, the concentration of calcium chloride is not particularly limited, and is, for example, 0.005 mol / L or more and 0.05 mol / L or more, and 0.5 mol / L or less, less than 0.5 mol / L, and 0.1 mol / L. It is L or less. When the concentration of calcium chloride is within the above range, for example, more carbon dioxide can be fixed.

The temperature of the mixed solution is not particularly limited, and is, for example, 30 to 100 ° C., 70 ° C. or higher, 70 ° C. to 80 ° C., and 70 ° C. According to the present invention, as described above, even when a high concentration (for example, 0.2 N or more) of sodium hydroxide is generated due to high heat, the concentration can be reduced. Therefore, the present invention can be applied, for example, even when the mixed solution has a high heat.

The pH of the mixed solution is not particularly limited, and for example, the pH of the mixed solution containing 0.05 N sodium hydroxide and 0.05 mol / L calcium chloride is about 12. When the concentration adjusting step is included, the pH is as described above.

In the contact step, the method of contacting the mixed liquid with the gas containing carbon dioxide is not particularly limited, and for example, the mixed liquid is brought into contact by feeding the gas into the mixed liquid. Examples thereof include standing or contacting the mixed solution in a state where a flow is generated, contacting the mixed solution in a atomized state, and contacting the mixed solution in a recirculated state. “Contacting the mixed liquid with a flow generated” may mean, for example, contacting the mixed liquid in a shaken state, or contacting the mixed liquid by flowing the mixed liquid in a container. You may. When the mixed solution is flowed, the mixed solution may be flowed in one direction or recirculated. Further, as described later, they may be brought into contact with each other by a gas-liquid mixing means including a liquid circulation flow path and a pump.

When the mixed solution is brought into contact with the gas containing carbon dioxide by feeding the gas into the mixed solution, "feeding" the gas can be, for example, "bubbling". .. The bubbling conditions are not particularly limited, and for example, 3 mL of 0.1 N sodium hydroxide solution and 3 mL of the calcium chloride solution of 0.1 mol / L are put into a 10 mL test tube and mixed, and the mixture is described. The liquid can be bubbling for ^{10 seconds (about 20 cm 3} ) using carbon dioxide (manufactured by Koike Kogyo Co., Ltd.). The bubbling can, for example, eject carbon dioxide from the tip of a pastur pipette. Further, for example, a bubbling device for aquarium organisms (product name: Bukubuku, manufactured by Kotobuki Kotobuki Co., Ltd.) can be used. Further, for example, a bubbling device (product name: Micro bubbler (F-1056-002), manufactured by Front Industry Co., Ltd.) can be used. The time for bubbling can be appropriately set, for example, as long as the formed precipitate does not disappear by a further reaction. For example, 5 seconds to 60 seconds, 5 seconds to 40 seconds, 5 seconds to 30 seconds, etc. And can be 1-2 minutes, and 1.5 hours, 9 hours, 12 hours, and the like.

By feeding the gas into the mixture in the contacting step, the gas can be bubbled and fed into the mixture. The size (diameter) of the bubble is determined, for example, according to the size of the inlet for feeding the gas. For example, when the gas is fed from the porous structure, the size of the bubble is determined according to the size of the pores of the porous structure.

The size of the bubbles (bubbles, bubbles), the number concentration, and the like can be appropriately set and are not particularly limited. The size of the bubble can be on the order of centimeters, millimeters, micrometers and nanometers, for example. The bubble includes, for example, a fine bubble. The fine bubble is a bubble having a sphere-equivalent diameter of 100 μm or less. The fine bubbles include microbubbles having a diameter of 1 to 100 μm and ultrafine bubbles (also referred to as nanobubbles) having a diameter of 1 μm or less. By setting the bubble to a small size such as a fine bubble, for example, the surface area of the bubble can be increased and the reaction in the contacting step can be promoted. By setting the bubble to a size larger than the fine bubble, for example, the gas pressure required for feeding the gas can be reduced.

The size of the bubble can be measured by, for example, a general method. Specifically, for example, the size of the bubble can be measured by taking a picture including the bubble and a predetermined scale and comparing the size of the bubble with the scale in the picture. In addition, particle size distribution measurement methods such as laser diffraction / scattering method, dynamic light scattering method, particle trajectory analysis method, resonance mass measurement method, electrical detection band method, dynamic image analysis method, and shading method are used. can do.

In the contacting step, when the mixed solution is brought into contact with the gas while the mixed solution is allowed to stand, the contacting conditions are not particularly limited, and for example, a PET having a volume of 2 L and having a general shape is not particularly limited. After equilibrating the inside of the bottle (commercially available) with the atmosphere, 10 mL of the mixed solution can be put into the PET bottle, and the PET bottle can be allowed to stand upright with the bottom surface facing down. The contact time can be, for example, 15 minutes, 30 minutes, and 60 minutes after the contact, and overnight contact.

In the contact step, "contacting the mixed liquid with the gas while generating a flow in the mixed liquid" means, for example, that the mixed liquid and the gas are brought into contact with each other while the mixed liquid is shaken. The mixed liquid may be brought into contact with the gas by flowing the mixed liquid in the container, or the upper part (ceiling, etc.) of the container may be brought into contact with the space inside the container. ) Etc., the mixed liquid may be brought into contact with the gas by adding the mixed liquid (for example, adding in the form of a shower or a mist).

In the contact step, when the mixed solution is brought into contact with the gas in a state where the mixed solution is shaken, the shaking conditions are not particularly limited, and for example, 10 mL of the mixed solution is added. An octagonal plastic bottle (commercially available) can be shaken using a shaker (BR-21UM, manufactured by TAITEK) at 120 rpm. The shaking conditions are as follows: For example, a container having a volume of 2 L containing 50 mL of the mixed solution is vigorously shaken by an adult male hand 1 to 4 times with one shaking for 30 seconds. be able to. The shaking of 1 to 4 times can be performed, for example, immediately after the contact, 30 seconds, 2 minutes, 5 minutes, and 4 hours, respectively.

In the contacting step, when the mixed liquid is brought into contact with the gas in a atomized state, the conditions for contacting the mixed liquid are not particularly limited, and for example, a container having a volume of 2 L containing the gas. In addition, about 4 mL of the mixed solution can be sprayed 10 times at 5-second intervals using a sprayer (commercially available). The mist-like mixed solution may be added in a shower-like or mist-like form from the upper part of the container to the space inside the container, for example.

The contact step includes, for example, a first contact step and a second contact step, and the first contact step involves contacting a solution containing sodium hydroxide with a gas containing carbon dioxide, and the second contact step. In the contact step of, calcium chloride may be added to the solution after the first contact step.

In the first contact step, a solution containing sodium hydroxide is brought into contact with a gas containing carbon dioxide. In the first contact step, the reaction between sodium hydroxide and carbon dioxide produces sodium hydrogen carbonate (NaHCO ₃ ) and sodium carbonate (Na ₂ CO ₃ ), and carbon dioxide can be fixed (absorbed).

In the first contact step, calcium chloride is not added. Therefore, according to the present invention, even when a high concentration (for example, 0.2 N or more) of sodium hydroxide is used in the first contact step, calcium hydroxide is not generated by the reaction with calcium chloride. .. Therefore, in the subsequent second contact step, it is possible to prevent calcium hydroxide from being generated due to the reaction between calcium chloride and high-concentration sodium hydroxide, and more carbon dioxide can be fixed.

According to the first contact step, for example, the concentration of sodium hydroxide can be 0.2 N or less, less than 0.2 N, and 0.1 N or less. Thereby, for example, in the second contact step, the formation of calcium hydroxide can be suppressed and more carbon dioxide can be fixed.

In the first contact step, the contacting means for bringing the solution into contact with the gas containing carbon dioxide is not particularly limited, and the above-mentioned mixed solution and the gas containing carbon dioxide are brought into contact with each other. The description of the method can be incorporated.

In the second contact step, calcium chloride is added to the solution after the first contact step. By reacting sodium hydrogen carbonate or sodium carbonate produced in the first contact step with calcium chloride by the second contact step, calcium carbonate can be generated and carbon dioxide can be fixed.

In the second contact step, the contact with the gas containing carbon dioxide may be terminated. Further, the second contact step may be performed while contacting the gas containing carbon dioxide.

In the second contact step, the concentration of the calcium chloride in the mixed solution after the addition is not particularly limited, and is, for example, 0.005 mol / L or more, 0.05 mol / L or more, and 0.5 mol / L or less. , Less than 0.5 mol / L, and less than 0.1 mol / L. When the concentration of calcium chloride is within the above range, for example, more carbon dioxide can be fixed.

In the second contact step, the pH of the mixed solution after the addition is not particularly limited, and for example, the pH of the mixed solution containing 0.05 N sodium hydroxide and 0.05 mol / L calcium chloride is about. It is twelve.

The method for fixing carbon dioxide of the present invention further includes, for example, a dilution step, in which the dilution step may dilute the solution after the first contact step. The method for diluting is not particularly limited, and for example, distilled water can be added. The dilution ratio can be set as appropriate, and can be diluted to, for example, 1/10. By the dilution step, for example, the concentration of sodium hydroxide can be reduced to 0.2 N or less, less than 0.2 N, and 0.1 N or less.

The method for fixing carbon dioxide of the present invention further includes, for example, a temperature holding step, and the temperature holding step can hold the temperature of the mixed solution at a high temperature. The high temperature is, for example, 70 to 100 ° C, 70 ° C to 80 ° C, 70 ° C or higher, and 70 ° C. The temperature holding step can be carried out by a general heating device or the like.

The method for fixing carbon dioxide of the present invention further includes, for example, a cooling step, and the cooling step may cool the mixed solution after the contact step. In the cooling step, for example, the high-temperature mixed solution can be cooled to 5 ° C. to room temperature. The high temperature is, for example, as described above. The cooling step can be carried out by a general cooling device or the like.

The method for fixing carbon dioxide of the present invention further includes, for example, a product recovery step, and the product recovery step may recover the reaction product in the mixed solution after the contact step. The reaction product is, for example, calcium carbonate (CaCO ₃ ). In the product recovery step, for example, solid calcium carbonate can be recovered. The product recovery step may be filtered by, for example, a filter or the like. The filter is not particularly limited, and examples thereof include an unbleached coffee filter (manufactured by Kanae Paper Works Co., Ltd.).

The present inventor has found that the reaction product produced by the contact step tends to adhere to the reaction vessel, the gas-liquid mixing means, and the like. Therefore, the product recovery step may include a mixing step of mixing the fixed reaction product in the mixed solution and a separation step of separating the mixed reaction product. In the mixing step, for example, the reaction product may be scraped off, or the reaction product may be solubilized with a drug (for example, hydrochloric acid (HCl)) or the like.

In the contacting step, as the contacting means for bringing the mixture containing sodium hydroxide and calcium chloride into contact with the gas containing carbon dioxide, the description of the device for producing immobilized carbon dioxide, which will be described later, may be incorporated. can.

Next, the electrolysis step will be described. In the electrolysis step, the mixed solution after the contact is electrolyzed to obtain a mixed solution after electrolysis. In the electrolysis step, other configurations and conditions are not particularly limited.

According to the method for fixing carbon dioxide of the present invention, by including the electrolysis step, sodium chloride (NaCl) generated in the contact step can be electrolyzed to produce sodium hydroxide (NaOH). Then, by reusing the post-electrolysis mixed solution containing sodium hydroxide in the contacting step, a circulating carbon dioxide fixing method can be obtained.

In the electrolysis step, it is sufficient that sodium chloride (NaCl) generated in the contact step can be electrolyzed, and the conditions and the like are not particularly limited, and for example, the description of Examples described later can be referred to. In the electrolysis step, by applying a voltage to the mixed solution, a reduction reaction occurs at the cathode and an oxidation reaction occurs at the anode, and sodium chloride in the mixed solution can be chemically decomposed. Then, chlorine (Cl ₂ ) is generated near the anode, hydrogen (H ₂ ) is generated near the cathode, and sodium hydroxide is generated in the mixed solution after electrolysis.

In the electrolysis step, the electrolysis means for producing the mixed solution after electrolysis by electrolyzing the mixed solution after the contact can refer to the description of the carbon dioxide fixing device described later. In the carbon dioxide fixing device described later, the case where the electrolytic chamber is divided into an anode chamber and a cathode chamber by a partition wall will be shown. However, the present invention is not limited to this, and the electrolysis means may be in the form of not using a partition wall (diaphragm). Specifically, for example, it is possible to use mercury for the cathode without using a diaphragm, considering the effect on the human body.

Then, in the method for fixing carbon dioxide of the present invention, as described above, the mixed solution after electrolysis is reused as the mixed solution in the contacting step.

In the contacting step, the configuration for reusing the mixed solution after electrolysis as the mixed solution is not particularly limited, and the description of the device for producing immobilized carbon dioxide, which will be described later, can be referred to.

In the contact step and the electrolysis step, for example, the contact step is first carried out, then the electrolysis step is carried out, and then, in the contact step, the post-electrolysis mixture is reused. You may. In this case, for example, first, in the first contact step, a mixture containing sodium hydroxide and further containing calcium chloride is brought into contact with a gas containing carbon dioxide. Next, in the electrolysis step, the mixed solution after the contact is electrolyzed to obtain a mixed solution after electrolysis. Then, in the second contact step, the mixed solution after electrolysis is reused as the mixed solution.

The method for fixing carbon dioxide of the present invention may further include, for example, an electrolysis step of producing sodium hydroxide by electrolyzing a sodium chloride solution before the contact step. In this case, for example, first, sodium hydroxide can be produced by the step of electrolyzing the sodium chloride, and then the contact step and the electrolysis step can be carried out as described above. In this case, according to the method for fixing carbon dioxide of the present invention, carbon dioxide can be fixed to calcium carbonate, hydrogen, and chlorine without preparing sodium hydroxide.

The steps may be performed in the same order as described above, or may be performed in parallel. Each of the above steps can be repeated, for example.

In each of the steps, for example, it may be determined whether or not to proceed to the next step. The determination is not particularly limited, and for example, the concentration, pH, turbidity, voltage, and water pressure of a predetermined substance (for example, sodium hydroxide, carbon dioxide, hydrogen, chlorine) in the carbon dioxide fixative or gas. It can be performed based on the measured values such as, and the elapsed time. The determination may be made by a computer or by an operator. When proceeding to the next step, for example, pumps 53, 70 and 81, flow rate adjusting means 54, 64 and 82, anode 121A and cathode 121B, carbon dioxide fixative charging means 20A to C, and gas feeding means 30 described later. Etc. can be operated by a computer, an operator, or the like.

(Manufacturing method of immobilized carbon dioxide)
As described above, the method for producing immobilized carbon dioxide of the present invention includes an immobilization step of immobilizing carbon dioxide, and the immobilization step is carried out by the method of immobilizing carbon dioxide of the present invention. The method for producing immobilized carbon dioxide of the present invention is characterized by including the immobilization step, and other steps and conditions are not particularly limited. The method for fixing carbon dioxide of the present invention is as described above. The conditions of the immobilization step are not particularly limited, and are, for example, the same as those described in the method for immobilizing carbon dioxide of the present invention.

[Embodiment 2]
(Carbon dioxide fixation device)
FIG. 1 is a schematic cross-sectional view showing an example of the case where the carbon dioxide fixing device 1 of the present embodiment is viewed from the side. In addition, in FIG. 1, the inside of the carbon dioxide fixing device 1 is shown perspectively. As shown in FIG. 1, the carbon dioxide fixing device 1 includes a reaction vessel 10, carbon dioxide fixing agent charging means 20A and 20B, and a gas feeding means 30 as a gas-liquid mixing means. Further, the carbon dioxide fixing device 1 includes gas extraction units 40A to C and liquid extraction units 50. In FIG. 1, the reaction vessel 10 contains a carbon dioxide fixative, which will be described later. Further, the gas containing carbon dioxide is supplied from the gas feeding means 30 into the carbon dioxide fixing agent in the reaction chamber 11. Further, in the electrolytic chamber 12, the carbon dioxide fixative is electrolyzed, and as a result, gas bubbles are generated from the anode 121A and the cathode 121B, respectively.

As shown in FIG. 1, the reaction vessel 10 includes a reaction chamber 11 and an electrolysis chamber 12. The electrolytic chamber 12 includes an anode chamber 12A and a cathode chamber 12B. In the present embodiment, the anode chamber 12A and the cathode chamber 12B are separated by a partition wall 13A and a partition wall 13B, and the partition wall 13A and the partition wall 13B form a reaction chamber 11. Further, the anode chamber 12A, the reaction chamber 11, and the cathode chamber 12B are connected at the non-installed portion of the partition wall 13A and the partition wall 13B. As a result, the liquid can be sent from the reaction chamber 11 to the anode chamber 12A and the cathode chamber 12B, and from the anode chamber 12A and the cathode chamber 12B to the reaction chamber 11, respectively. In addition, in the carbon dioxide fixation device 1 of the present embodiment, it can be said that the electrolysis chamber 12 includes the reaction chamber 11.

Since the carbon dioxide fixation device 1 of the present embodiment has the above configuration, the carbon dioxide fixative is reacted with carbon dioxide in the reaction chamber 11, and the reaction chamber 11 is transferred to the electrolysis chamber 12 after the reaction. The carbon dioxide fixative can be sent, and in the electrolytic chamber 12, the carbon dioxide fixing agent after the reaction is electrolyzed, and the carbon dioxide fixing agent after the electrolysis is transferred from the electrolytic chamber 12 to the reaction chamber 11. The carbon dioxide fixative after electrolysis can be reused as the carbon dioxide fixative in the reaction chamber 11.

The reaction vessel 10 is not particularly limited as long as it can accommodate the carbon dioxide fixative in the reaction chamber 11 and can electrolyze the carbon dioxide fixative after the reaction in the electrolytic chamber 12. Examples of the material of the reaction vessel 10 include plastic, glass, and ceramics. The material, capacity, size, height, shape, etc. of the reaction vessel 10 can be appropriately set.

The carbon dioxide fixative is, for example, a liquid containing at least one of sodium hydroxide (NaOH) and potassium hydroxide (KOH). At least one of the sodium hydroxide and potassium hydroxide is, for example, sodium hydroxide. Further, the carbon dioxide fixative may be a liquid containing at least one of sodium chloride (NaCl) and potassium chloride (KCl), for example. In this case, sodium hydroxide and potassium hydroxide can be produced by electrolysis, respectively.

The carbon dioxide fixing agent contains at least one of sodium hydroxide and potassium hydroxide as a first fixing agent, and further, as a second fixing agent, a chloride of a group 2 element (alkaline earth metal), and It may contain at least one of the chlorides of the divalent metal element. At least one of the chloride of the Group 2 element and the chloride of the divalent metal element is, for example, calcium chloride (CaCl ₂ ).

The electrolytic chamber 12 includes an anode chamber 12A and a cathode chamber 12B. The anode chamber 12A and the cathode chamber 12B are provided with the anode 121A and the cathode 121B, respectively. The anode 121A and the cathode 121B are not particularly limited, and for example, a platinum coated titanium mesh electrode (manufactured by Tanaka Metal Co., Ltd.) can be used. The anode 121A and the cathode 121B are each connected to a power supply device (not shown) by a conducting wire. The power supply device is not particularly limited, and for example, a rectifier YG-1502D + (manufactured by YAOGONG), a DC power supply device, STP3010H, a Shenzhen Tengen Power Supply Co., Ltd., and the like can be used.

The partition wall 13A and the partition wall 13B are not particularly limited, and examples thereof include plastic, ceramics, and glass. In the present embodiment, as described above, the partition wall 13A and the partition wall 13B have a non-installed portion, and the anode chamber 12A, the reaction chamber 11, and the cathode chamber 12B are connected to each other in the non-installed portion. However, the present invention is not limited to this, and when the partition wall 13A and the partition wall 13B are formed by an ion exchange membrane or the like, the non-installed portion may not be provided.

The carbon dioxide fixative charging means 20A and 20B can charge the carbon dioxide fixative into the reaction vessel 10. The carbon dioxide fixative charging means 20A and 20B may be pipes, hoses, or the like. Further, the carbon dioxide fixative charging means 20A and 20B are openings of the reaction vessel 10, and the carbon dioxide fixative may be charged through the openings, for example, by an operator or the like.

In this modification, the carbon dioxide fixative charging means 20A is provided above the anode chamber 12A, and the carbon dioxide fixing agent charging means 20B is provided below the anode chamber 12A. However, they are not limited to these. Further, the carbon dioxide fixing device 1 may include one carbon dioxide fixing agent input means 20.

Further, in this modification, the carbon dioxide fixative charging means 20A and 20B are provided on the anode chamber 12A side. However, the present invention is not limited to this, and for example, the carbon dioxide fixative charging means 20A and 20B may be provided on the cathode chamber 12B side.

In the carbon dioxide fixing device 1 of the present embodiment, as an example, sodium chloride can be charged from the carbon dioxide fixing agent charging means 20A, and calcium chloride can be charged from the carbon dioxide fixing agent charging means 20B. However, the present invention is not limited to this, and the carbon dioxide fixative charging means 20A and 20B may be capable of charging at least one of the above-mentioned carbon dioxide fixatives. Further, as will be described later, water such as distilled water may be added.

As described above, the carbon dioxide fixing device 1 of the present embodiment includes the gas feeding means 30 as the gas-liquid mixing means. As shown in FIG. 1, the gas feeding means 30 is inserted into the reaction chamber 11, and a plurality of holes are provided at the insertion end portion 31, and the carbon dioxide in the reaction chamber 11 is provided from the plurality of holes. A gas containing carbon dioxide can be introduced into the fixative. Thereby, the gas can be mixed with the carbon dioxide fixative.

The material, length, thickness, shape, and the like of the gas feeding means 30 can be appropriately set. Examples of the gas feeding means 30 include a tubular structure such as a pipe and a hose.

The insertion end 31 can be formed of, for example, plastic, ceramics, metal, glass, and porous materials. Examples of the porous material include air stones. The number, size, and shape of the plurality of holes are not particularly limited, and can be appropriately set according to a desired reaction rate, gas pressure of the gas, and the like.

In this embodiment, the insertion end 31 is provided in the lower part of the reaction chamber 11. The "lower part" is below the liquid level, and examples thereof include the position of the lower half of the space in the first reaction vessel 10. By providing the insertion end portion 31 at a lower portion, for example, the distance between the insertion end portion 31 and the liquid surface becomes larger, so that the gas supplied from the insertion end portion 31 reaches the liquid surface. The distance to is longer and the amount of reaction can be increased.

The insertion end 31 is coated with, for example, a water repellent and at least one of an electrically negative material. The water repellent can also be called a waterproofing agent. The water repellent, the property of dislike carbonate ion _(CO ^{3 2-).} Examples of the electrically negative material include a negatively charged ion exchange resin. The coating on the insertion end 31 is sprayed on the insertion end 31 several times using, for example, a fluororesin-based waterproof spray (product name Loctite, product number DBS-422, manufactured by Henkel Japan Ltd.) for 30 minutes. Can be left alone. The coating can prevent the reaction product from sticking to the vicinity of the insertion end 31, and can prevent the reaction from being suppressed due to the sticking of the reaction product. Suppression of the reaction by sticking the reaction product does not pose a problem when the gas containing carbon dioxide and the sodium hydroxide solution containing no calcium chloride are brought into contact with each other. On the other hand, in a state where sodium hydroxide and calcium chloride coexist in the solution, carbon dioxide and hydroxide ion (OH ⁻ ) react with each other due to contact between the gas containing carbon dioxide and the solution, which is generated. Calcium carbonate is produced by the further reaction of carbonate ions (CO ₃ ^2- ) with calcium ions (Ca ^2+). Since these reactions are fast reactions, it is considered that the reaction product adheres to the vicinity of the insertion end 31. Such sticking of the reaction product is a problem uniquely found by the present inventor.

The gas-liquid mixing means is not particularly limited as long as it can mix a gas containing carbon dioxide with the carbon dioxide fixative contained in the reaction chamber 11. Other examples of the gas-liquid mixing means will be described later.

The gas extraction units 40A to C can extract gas from the anode chamber 12A, the reaction chamber 11, and the cathode chamber 12B, respectively. The gas extraction portions 40A to C may be pipes, hoses, or the like, or may be openings of the reaction vessel 10. _{For example, chlorine (Cl 2} ) and hydrogen (H ₂ ) can be taken out from the gas extraction portions 40A and B of the anode chamber 12A and the cathode chamber 12B, respectively. From the gas extraction unit 40C of the reaction chamber 11, for example, the gas containing carbon dioxide from which carbon dioxide has been removed is discharged by the contact with the carbon dioxide fixative.

The liquid take-out unit 50 can take out the carbon dioxide fixative, the reaction product, and the like after the reaction contained in the reaction vessel 10. As shown in FIG. 1, the liquid take-out portion 50 is an inclined surface at the bottom of the reaction vessel 10, and a pipe, a hose, or the like is connected to the lowermost portion of the inclined surface. However, the present invention is not limited to this, and it is sufficient that the liquid extraction unit 50 can extract the carbon dioxide fixative, the reaction product, and the like. Examples of the product include calcium carbonate (CaCO ₃ ) and calcium hydroxide (Ca (OH) ₂ ) as described above.

In the present embodiment, the liquid extraction unit 50 includes a filter 51. The filter 51 may be, for example, a device called a filter press method in which filter cloths are laminated and pressure is applied to filter them, or a device in which a filter cloth or a cartridge is placed in a filter and filtered. As the filter 51, for example, one having a filtration degree of 1 μm or more and 1 μm can be used. Specific examples of the filter 51 include an unbleached coffee filter (manufactured by Kanae Paper Works Co., Ltd.). Since calcium carbonate is a solid as described above, for example, when the liquid extraction unit 50 includes a filter 51, the solid reaction product can be obtained by separating it from the carbon dioxide fixative. ..

(Modification example 1)
As shown in FIG. 2, the carbon dioxide fixing device 1 of the present modification includes a liquid circulation flow path 60 and a pump 70 as the gas-liquid mixing means. The liquid circulation flow path 60 includes a liquid suction end 61 and a liquid discharge end 62, the liquid suction end 61 is connected to the cathode chamber 12B, and the liquid discharge end 62 is inserted into the reaction chamber 11. The carbon dioxide fixative can be sucked from the liquid suction end 61 and the sucked carbon dioxide fixator can be discharged from the liquid discharge end 62 by the pump 70.

The liquid circulation flow path 60 is not particularly limited, and examples thereof include pipes and hoses.

In this modification, the liquid circulation flow path 60 further includes an aspirator 63 as a gas-liquid mixing member, and the aspirator 63 can mix a gas containing carbon dioxide with the liquid flowing through the liquid circulation flow path 60. In this modified example, the aspirator 63 also serves as the liquid discharge end 62. The aspirator 63 can entrain the gas in the liquid by utilizing the jet of the liquid. The aspirator 63 may be attached with a hose for taking in the gas, for example. Specifically, the aspirator 63 is specifically made of, for example, an aspirator (water flow pump) metal (part number 1-689-02, manufactured by AS ONE Corporation) and an aspirator (water flow pump) made of metal (part number 1-689-04, manufactured by AS ONE Corporation). ) Etc. The gas-liquid mixing member is not particularly limited, and may be, for example, a mixer or the like. In FIG. 2, the hose connected to the aspirator 63 can take in a gas containing carbon dioxide from the outside. Then, the taken-in gas can be mixed with the sucked carbon dioxide fixative by the aspirator 63.

In this modification, the liquid circulation flow path 60 includes a flow rate adjusting means 64. The flow rate adjusting means 64 is not particularly limited, and examples thereof include a cock and a valve.

In this modification, the liquid suction end 61 is provided on the cathode chamber 12B side. However, the present invention is not limited to this, and for example, the liquid suction end portion 61 may be provided on the anode chamber 12A side.

The liquid suction end 61 may include, for example, filtration means. The filtration means can remove solid components contained in the carbon dioxide fixative. The filtration means is not particularly limited as long as it can remove the solid component contained in the carbon dioxide fixative. As the filtration means, for example, a commercially available strainer or the like can be appropriately used according to the diameter of the pipe of the liquid circulation flow path 60 or the like. This makes it possible to prevent, for example, the inflow of relatively large suspended matter or solidified precipitate into the liquid circulation flow path 60, and prevent the pump 70 from failing (damage of the impeller, etc.).

As described above, in this modification, the aspirator 63 also serves as the liquid discharge end 62. However, the present invention is not limited to this, and the aspirator 63 may be provided in the middle of the liquid circulation flow path 60. In this case, the liquid discharge end 62 can be formed of, for example, plastic, ceramics, metal, glass, and a porous material. It may also be the end of the liquid circulation flow path 60.

The liquid discharge end 62 may, for example, discharge the carbon dioxide fixative from the upper part of the reaction chamber 11 into the reaction chamber 11 in the form of a shower or mist. As the structure for discharging in the form of a shower or mist, a general spray or the like can be used.

In this modification, the liquid discharge end 62 is provided above the reaction chamber 11. The "upper part" is above the liquid level, and examples thereof include the position of the upper half of the space in the first reaction vessel 10. However, the present invention is not limited to this, and for example, a liquid discharge end portion 62 is provided in the lower part of the reaction chamber 11, and the sucked liquid can be released into the carbon dioxide fixative contained in the reaction chamber 11. It may be.

The liquid discharge end 62 may be provided with, for example, a plurality of pores, and the carbon dioxide fixative may be discharged from the plurality of pores into the carbon dioxide fixant in the reaction chamber 11. The number, size, and shape of the plurality of holes are not particularly limited, and can be appropriately set according to a desired reaction rate, the pressure of the discharged liquid, and the like.

Further, the liquid discharge end 62 may be capable of horizontally injecting the gas into the carbon dioxide fixative contained in the reaction chamber 11, for example. Thereby, for example, the contact time between the injected carbon dioxide fixative and the carbon dioxide fixative in the reaction chamber 11 can be made longer.

The pump 70 can, for example, apply pressure to the liquid flowing through the liquid circulation flow path 60. The pump 70 is not particularly limited, and a general pump can be used.

In this modification, the liquid circulation flow path 60 does not have to include the aspirator 63. In this case, for example, the sucked carbon dioxide fixative is vigorously ejected from the liquid discharge end 62 onto the liquid surface of the carbon dioxide fixative contained in the reaction chamber 11, whereby the ejected carbon dioxide fixative is vigorously ejected. Since the gas existing in the first reaction vessel 10 is involved in the carbon dioxide fixative, the carbon dioxide fixative and the gas can be mixed.

The configuration for vigorously ejecting the sucked carbon dioxide fixative is an alternative to or in addition to the configuration of the liquid discharge end 62, for example, increasing the pressure applied by the pump 70, of the liquid discharge end 62. It can be set as appropriate by reducing the size of the spout.

Further, in this case, the carbon dioxide fixing device 1 may include a gas taking-in means for taking the gas into the first reaction vessel 10. The gas intake means may be an opening provided in the first reaction vessel 10, a pipe, a hose, or the like. The gas intake means can, for example, take in the gas into the reaction chamber 11.

(Modification 2)
As shown in FIG. 3A, the carbon dioxide fixing device 1 of the present modification further includes a liquid ejecting unit 50, a liquid discharging unit 52, a pump 53, and a flow rate adjusting means 54. The liquid discharge unit 52 is inserted into the reaction chamber 11, and the carbon dioxide fixative can be sucked from the liquid take-out unit 50 by the pump 53, and the sucked carbon dioxide fixative can be discharged from the liquid discharge unit 52. be.

The liquid discharge unit 52 is not particularly limited as long as it can release the sucked carbon dioxide fixative. For the liquid discharge unit 52, for example, the description of the liquid discharge end portion 62 in the first modification can be referred to.

For the pump 53 and the flow rate adjusting means 54, for example, the description of the pump 70 and the flow rate adjusting means 64 in the first modification can be referred to.

In the carbon dioxide fixing device 1 of this modification, as shown in FIG. 3B, the liquid extraction unit 50 may also serve as the gas-liquid mixing means. In FIG. 3B, the carbon dioxide fixing device 1 includes a liquid take-out portion 50 instead of the liquid circulation flow path 60 which is the gas-liquid mixing means in the modified example 1, and the liquid discharge end portion in the modified example 1. Instead of 62, a liquid discharge unit 52 is included.

According to the carbon dioxide fixing device 1 of the present modification, first, the carbon dioxide fixing agent, the reaction product, and the like after the reaction contained in the reaction vessel 10 are taken out by the liquid extraction unit 50. Next, the reaction product or the like in the carbon dioxide fixative is separated by the filter 51. Next, the liquid release unit 52 releases the carbon dioxide fixative from which the reaction products and the like have been separated into the container 10 again. As a result, the carbon dioxide fixative from which the reaction products and the like have been separated can be reused.

[Embodiment 3]
(Carbon dioxide fixation device)
FIG. 4 is a schematic cross-sectional view showing an example of the case where the carbon dioxide fixing device 2 of the present embodiment is viewed from the side. In FIG. 4, the inside of the carbon dioxide fixing device 2 is shown perspectively. As shown in FIG. 4A, the carbon dioxide fixing device 2 includes a first reaction vessel 10A and a second reaction vessel 10B, and the first reaction vessel 10A is a reaction chamber 11 and a second reaction vessel. 10B is the electrolytic chamber 12. Further, the liquid can be sent from the first reaction vessel 10A to the second reaction vessel 10B by the container communication flow path 80A, and the liquid can be sent from the second reaction vessel 10B to the first reaction vessel 10A by the container communication flow path 80B. be. Other than these points, it is the same as the above-described embodiment.

As shown in FIG. 4A, the electrolytic chamber 12 includes an anode chamber 12A, an intermediate chamber 12C, and a cathode chamber 12B. In the present embodiment, the anode chamber 12A and the cathode chamber 12B are separated by a partition wall 13A and a partition wall 13B, and an intermediate chamber 12C is formed between the partition wall 13A and the partition wall 13B. Further, the anode chamber 12A, the intermediate chamber 12C, and the cathode chamber 12B are connected at a non-installed portion of the partition wall 13.

Since the carbon dioxide fixation device 2 of the present embodiment has the above configuration, the carbon dioxide fixative is reacted with carbon dioxide in the reaction chamber 11, and the container communication flow path is transmitted from the reaction chamber 11 to the electrolysis chamber 12. With 80A, the carbon dioxide fixative after the reaction can be sent, and in the electrolytic chamber 12, the carbon dioxide fixative after the reaction is electrolyzed, and the carbon dioxide fixative after the electrolysis is electrolyzed. The liquid can be sent from the electrolytic chamber 12 to the reaction chamber 11 by the container communication flow path 80B, and the carbon dioxide fixing agent after electrolysis can be reused as the carbon dioxide fixing agent in the reaction chamber 11.

In the second reaction vessel 10B, the anode chamber 12A, the intermediate chamber 12C, and the cathode chamber 12B are not particularly limited, and the above-mentioned description of the anode chamber 12A and the cathode chamber 12B can be referred to. The intermediate chamber 12C is the same as the anode chamber 12A and the cathode chamber 12B except that an electrode is not provided.

The container communication flow path 80A is not particularly limited, and examples thereof include pipes and hoses. As shown in FIG. 4A, the container communication flow path 80A may include a pump 81A and a flow rate adjusting means 82A. The pump 81A and the flow rate adjusting means 82A are the same as the pump 70 and the flow rate adjusting means 64 described above.

In the carbon dioxide fixing device 2 of the present embodiment, as shown in FIG. 4A, the first reaction vessel 10A includes a liquid extraction unit 50. The liquid extraction unit 50 includes a filter 51.

The liquid take-out unit 50 further includes, for example, a liquid discharge unit 52, a pump 53, and a flow rate adjusting means 54, as described in the second modification of the second embodiment, and the liquid discharge unit 52 is placed in the second reaction vessel 10B. May be connected. As a result, the carbon dioxide fixative from which the reaction products and the like have been separated can be released into the second reaction vessel 10B and reused.

In this case, the liquid take-out unit 50 may also serve as the container communication flow path 80A. That is, in FIG. 4A, the carbon dioxide fixing device 2 may include the liquid take-out unit 50 instead of the container communication flow path 80A.

As shown in FIG. 4A, the container communication flow path 80B may include a pump 81B and a flow rate adjusting means 82B. The pump 81B and the flow rate adjusting means 82B are the same as the pump 70 and the flow rate adjusting means 64 described above.

Next, FIG. 4B shows another embodiment of the carbon dioxide fixing device 2 of the present embodiment. In this embodiment, in the carbon dioxide fixing device 2, the container communication flow path 80B also serves as the gas-liquid mixing means. The container communication flow path 80B includes an ejector 83. Other than this point, it is the same as the form of FIG. 4 (A).

In this embodiment, the container communication flow path 80B can refer to the description of the liquid circulation flow path 60.

The container communication flow path 80B includes an aspirator 83 as a gas-liquid mixing member, and the aspirator 83 can mix a gas containing carbon dioxide with the liquid flowing through the container communication flow path 80B. The aspirator 83 is the same as the above-mentioned aspirator 63.

In the present embodiment, the aspirator 83 also serves as the liquid discharge end of the container communication flow path 80B. However, the present invention is not limited to this, and the aspirator 83 may be provided in the middle of the container communication flow path 80B. In this case, the liquid discharge end can be formed of, for example, plastic, ceramics, metal, glass, and a porous material. It may also be the end of the container communication flow path 80B.

The liquid discharge end portion of the container communication flow path 80B may, for example, discharge the carbon dioxide fixative from the upper part of the reaction chamber 11 into the reaction chamber 11 in the form of a shower or mist. As the structure for discharging in the form of a shower or mist, a general spray or the like can be used.

The effects of releasing the carbon dioxide fixative in the form of a shower or mist include the following points. As described above, in the contact between the gas and the carbon dioxide fixative, the reaction between calcium chloride and high-concentration sodium hydroxide causes precipitation of calcium hydroxide, whereby the amount of calcium carbonate synthesized by the contact. May decrease. On the other hand, by releasing the carbon dioxide fixative in the form of a shower or a mist, first, the sodium hydroxide contained in the carbon dioxide fixative released from the liquid discharge end and the sodium hydroxide in the reaction chamber 11 are said to be present. It reacts by contact with a gas (the first contact step), and then the products (sodium hydrogen carbonate and sodium carbonate) of the reaction and calcium chloride contained in the carbon dioxide fixative in the reaction chamber 11 Reacts. Therefore, it is possible to prevent the formation of calcium hydroxide due to the reaction between calcium chloride and high-concentration sodium hydroxide, and it is possible to fix more carbon dioxide.

The carbon dioxide fixing device 2 of the present embodiment is a two-tank type fixing device using the first reaction vessel 10A and the second reaction vessel 10B corresponding to the reaction chamber 11 and the electrolysis chamber 12, respectively. Therefore, even when high-concentration sodium hydroxide is generated in the electrolytic chamber 12, high-concentration water in the reaction chamber 11 is adjusted by adjusting the flow rate to the reaction chamber 11 and adjusting the release form as described above. Contact between sodium oxide and calcium chloride can be prevented. Therefore, it is possible to prevent the formation of calcium hydroxide due to the reaction between calcium chloride and high-concentration sodium hydroxide. From the above, it is considered that the carbon dioxide fixing device 2 of the present embodiment is suitable for the case where high-concentration carbon dioxide is emitted, such as in a power plant or the like.

[Embodiment 4]
(Carbon dioxide fixation device)
FIG. 5 is a schematic cross-sectional view showing an example of the case where the carbon dioxide fixing device 3 of the present embodiment is viewed from the side. In FIG. 5, the inside of the carbon dioxide fixing device 3 is shown perspectively. As shown in FIG. 5A, the carbon dioxide fixing device 3 includes a first reaction vessel 10A and a second reaction vessel 10B, and the first reaction vessel 10A is a second reaction chamber 11B and a second reaction vessel 10B. The reaction vessel 10B includes an electrolytic chamber 12 (anode chamber 12A and a cathode chamber 12B) and a first reaction chamber 11A. In the second reaction vessel 10B, the anode chamber 12A and the first reaction chamber 11A are separated by a partition wall 13A which is a cation exchange membrane without providing the non-installed portion. Further, the liquid can be sent from the second reaction vessel 10B to the first reaction vessel 10A by the container communication flow path 80. The first reaction vessel 10A is provided with a liquid take-out portion 50. The liquid discharge section 52 of the liquid take-out section 50 is inserted into the anode chamber 12A, and the carbon dioxide fixative is sucked from the liquid take-out section 50 by the pump 53, and the sucked carbon dioxide fixative is used as the liquid release section. It can be released from 52. Further, the cathode chamber 12B includes a carbon dioxide fixative charging means 20C. Other than these points, it is the same as the above-described embodiment.

The partition wall 13A which is a cation exchange membrane is not particularly limited, and specific examples thereof include Nafion (registered trademark) N324 and the like. In addition, asbestos can be used in consideration of the effect on the human body.

The carbon dioxide fixative charging means 20C is the same as the carbon dioxide fixing agent charging means 20A and B described above. Distilled water can be added to the carbon dioxide fixative charging means 20C, for example. Thereby, for example, the water required for electrolysis can be replenished. In addition, the concentration of sodium hydroxide produced in the second reaction vessel 10B by electrolysis can be adjusted.

In the present embodiment, the container communication flow path 80 can send liquid from the cathode chamber 12B of the second reaction vessel 10B to the first reaction vessel 10A. Thereby, for example, it is possible to prevent the mixing of chlorine.

Since the carbon dioxide fixation device 3 of the present embodiment has the above configuration, the carbon dioxide fixative is reacted with carbon dioxide in the first reaction chamber 11A and the second reaction chamber 11B, and the second reaction chamber 11B The carbon dioxide fixative after the reaction can be sent to the electrolytic chamber 12 by the liquid take-out unit 50, and the carbon dioxide fixative after the reaction is electrolyzed in the electrolytic chamber 12 to electrolyze the carbon dioxide fixant. The carbon dioxide fixative afterwards can be sent from the electrolytic chamber 12 to the first reaction chamber 11A, and in the first reaction chamber 11A and the second reaction chamber 11B, the carbon dioxide fixative after electrolysis is transferred. It can be reused as the carbon dioxide fixative.

Further, the carbon dioxide fixing device 3 of the present embodiment has the above-mentioned configuration, so that the solution containing sodium hydroxide and the gas containing carbon dioxide are brought into contact with each other in the first reaction chamber 11A (the first reaction chamber 11A). (Contact step), after the first contact step, calcium chloride can be added to the solution in the second reaction chamber 11B (the second contact step). The first contact step and the second contact step are as described above.

According to the carbon dioxide fixation device 3 of the present embodiment, for example, in the first reaction chamber 11A, the reaction product calcium carbonate (CaCO ₃ ) is not produced by the first contact step. Therefore, it is possible to prevent the problem that the reaction product generated by the contact step sticks to the reaction vessel (second reaction vessel 10B), the gas-liquid mixing means (gas feeding means 30), or the like. ..

Further, according to the carbon dioxide fixing device 3 of the present embodiment, as described above, the anode chamber 12A and the first reaction chamber 11A do not have the non-installed portion, and the partition wall 13A which is a cation exchange membrane is provided. It is divided by. ^{Therefore, it is possible to prevent the chloride ion (Cl −} ) generated on the side of the anode chamber 12A from moving to the side of the first reaction chamber 11A. This can prevent, for example, the problem that the chloride ion reacts with the sodium hydroxide (NaOH) generated by the electrolysis to generate NaClO and the sodium hydroxide concentration in the first reaction chamber 11A decreases. can. _{Further, for example, it is possible to prevent the chlorine (Cl 2} ) generated on the side of the anode chamber 12A from being mixed with the gas containing carbon dioxide in the first reaction chamber 11A.

Next, FIG. 5B shows another embodiment of the carbon dioxide fixing device 3 of the present embodiment. As shown in FIG. 5B, the carbon dioxide fixing device 3 includes a liquid circulation flow path 60 and a pump 70 as the gas-liquid mixing means. The liquid circulation flow path 60 includes a liquid suction end portion 61, a liquid discharge end portion 62 which is an aspirator, and a flow rate adjusting means 64, and the liquid suction end portion 61 is connected to a cathode chamber 12B and is connected to a liquid discharge end portion. The 62 is inserted into the first reaction chamber 11A, and the carbon dioxide fixing agent can be sucked from the liquid suction end portion 61 by the pump 70, and the sucked carbon dioxide fixing agent can be discharged from the liquid discharge end portion 62. Is. Other than this point, it is the same as the form of FIG. 5 (A).

Next, a case where the method for fixing carbon dioxide is carried out using the carbon dioxide fixing device 3 of the present embodiment will be described.

First, prior to the step (S101), a solution containing sodium chloride is charged from the carbon dioxide fixing agent charging means 20B of the second reaction vessel 10B as the carbon dioxide fixing agent, and the carbon dioxide fixing agent charging means 20C is used. Inject water (START). Then, the solution is electrolyzed by the anode 121A and the cathode 121B connected to the power supply device to generate a sodium hydroxide solution (S100).

Next, the gas containing carbon dioxide is transferred from the gas feeding means 30 into the carbon dioxide fixative in the first reaction chamber 11A of the second reaction vessel 10B (S101; the first contact step). ..

Next, the carbon dioxide fixative after the reaction in the first contact step is sent from the second reaction vessel 10B to the first reaction vessel 10A by the vessel communication flow path 80 (S102). The carbon dioxide fixative after the reaction by the first contact step is, for example, a solution containing sodium hydrogen carbonate and sodium carbonate.

Next, calcium chloride is added as the second fixing agent in the carbon dioxide fixing agent from the carbon dioxide fixing agent charging means 20A of the first reaction vessel 10A (S103; the second contact step).

Next, the pump 53 sucks in the carbon dioxide fixative after the reaction in the second contact step from the liquid take-out unit 50, and the sucked carbon dioxide fixative is discharged into the anode chamber 12A. It is discharged from the part 52 (S104). The carbon dioxide fixative after the reaction by the second contact step is, for example, a solution containing sodium chloride.

In the step (S104), the solid reaction product can be separated from the carbon dioxide fixative by the filter 51. The reaction product of the solid is, for example, calcium carbonate.

Next, the sodium chloride solution released from the liquid discharge unit 52 is electrolyzed in the same manner as in the step (S100) to generate a sodium hydroxide solution (S105).

Then, after the step (S105), the steps after the step (S101) can be repeated. The steps may be performed in the same order as described above, or may be performed in parallel.

As described above, carbon dioxide can be fixed by reacting sodium hydroxide and calcium chloride with carbon dioxide to generate calcium carbonate. Further, by electrolyzing sodium chloride generated by the reaction, the reaction by each of the above steps can be repeated.

Next, examples of the present invention will be described. However, the present invention is not limited by the following examples. Commercially available reagents were used based on those protocols unless otherwise indicated.

[Example 1]
It was confirmed that calcium carbonate (CaCO _{3 ) was formed by adding calcium chloride (CaCl 2} ) after electrolyzing the sodium chloride (NaCl) solution.

The electrolyzer was manufactured as follows. As shown in FIG. 6, a plastic tapper wear (commercially available, size: 12x9x5 cm) having a volume of 500 ml was used as the container. An air hole (about 7 mm in diameter), a lead hole to the cathode plate (about 7 mm in diameter), and an introduction hole to the anode plate (about 1.7 cm in diameter) were formed in the lid of the container one by one. A 5x5 cm platinum-coated titanium mesh electrode (manufactured by Tanaka Metal Co., Ltd.) was used as the anode plate and the cathode plate, respectively. A 2 L PET bottle (commercially available) was cut to prepare a member including the mouth of the PET bottle. The conducting wire of the anode plate was passed through the mouth portion of the member. The anode plate was connected to the conducting wire so that the anode plate was surrounded by the members. Further, the mouth portion of the member was fitted into the introduction hole into the anode plate in the container and installed so that chlorine (Cl ₂ ) generated from the anode plate was released to the outside of the container. This prevented chlorine from being mixed into the gas in the container. The conductor of the anode plate and the conductor of the cathode plate were connected to a power supply device (rectifier YG-1502D + (manufactured by YAOGONG)), respectively.

Sodium chloride (manufactured by Wako Pure Chemical Industries, Ltd.) was diluted with distilled water to prepare a 10% sodium chloride solution. Further, calcium chloride (manufactured by Wako Pure Chemical Industries, Ltd.) was dissolved in distilled water to prepare a 0.1 mol / L calcium chloride solution.

200 mL of the 10% sodium chloride solution was placed in the container of the electrolyzer and energized using the power supply at about 8 V, 1.5 A for about 1 hour. In the energization, 100 V alternating current was converted into direct current and used. The pH of the solution was measured before and after the energization.

As a result, the pH of the solution before and after the energization was 7.5 and 11.0, respectively. From this, it was shown that sodium chloride was electrolyzed by the energization to produce sodium hydroxide (NaOH).

Further, after the energization, the solution near the cathode plate in the container was collected. In a 10 mL test tube, 1 ml of the collected solution and 1 ml of the 0.1 mol / L calcium chloride solution were placed and mixed. As a control, 1 ml of the 10% sodium chloride solution and 0.1 mol / L of the calcium chloride solution were mixed in the same manner without energization. The presence or absence of precipitation formation in the mixed solution after mixing was visually confirmed.

The result is shown in FIG. FIG. 7 is a photograph of the mixed solution, the left side shows the control, and the right side shows the state after the energization. As shown in FIG. 7, as a result of the energization, a white precipitate was formed in the mixed solution. On the other hand, when the energization was not performed, no precipitate was formed in the mixed solution. In the formed white precipitate, sodium hydroxide produced by the electrolysis reacts (absorbs) with _{carbon dioxide (CO 2} ) in the air to produce _{sodium carbonate (Na 2} CO _3). It is considered that sodium carbonate is calcium carbonate produced by reacting with calcium chloride.

As described above, it was confirmed that calcium carbonate was formed by adding calcium chloride after electrolyzing the sodium chloride solution.

[Example 2]
It was confirmed that calcium carbonate was formed by adding calcium chloride after electrolyzing the sodium chloride solution under different conditions.

The electrolyzer was manufactured as follows. As shown in FIG. 8, a plastic box (commercially available) having a volume of 1.85 L was used as the container. An air hole (about several mm in diameter), a lead hole to the cathode plate (about 2 cm in diameter), and an introduction hole to the anode plate (about 2 cm in diameter) were formed in the lid of the container one by one. As the anode plate and the cathode plate, the same ones as in Example 1 were used. Further, in the same manner as in Example 1, two of the members were produced, the anode plate and the cathode plate were attached to the members, respectively, and the members were installed in the introduction holes of the container. The anode plate and the cathode plate were connected to a power supply device (DC power supply device, STP3010H, manufactured by Shenzhen Tengen Power Supply Co., Ltd.). Further, as shown in FIG. 8, the container is provided with a small hole for inserting the hose of the bubbling device, and the bubbling device for aquarium organisms (product name: Bukubuku (air pump, hose, and air stone included in the set)). (Assembled) and Kotobuki Kotobuki Co., Ltd.) were installed to enable bubbling.

A 10% sodium chloride solution and a 0.1 mol / L calcium chloride solution were prepared in the same manner as in Example 1.

Electrolysis was performed by placing 700 mL of the 10% sodium chloride solution in the container of the electrolyzer and energizing for 22 hours using the power supply. The conditions for electrolysis were 9.65V and 0.9A at the start of energization, and 9.80V and 1.5A at 22 hours after energization. After the energization, the solution was collected as an electrolyzed solution. 0.75 ml of distilled water was added to 0.25 ml of the electrolyzed solution to dilute it, and 1 ml of the 0.1 mol / L calcium chloride solution was further added to prepare a mixed solution. The mixed solution was _{brought into contact with carbon dioxide (CO 2} 100%, manufactured by Koike Kogyo Co., Ltd.) by bubbling. The bubbling ejected carbon dioxide from the tip of a pastur pipette. The bubbling conditions were 40 ml for 10 seconds. After the contact, the mixture was centrifuged at 3,000 rpm for 10 minutes to separate the precipitate. Then, the supernatant of the test tube was removed with an ejector. Then, the weight of the test tube was measured before and after the contact, and the difference in the weight before and after the contact was calculated as the amount of precipitation. When the test tubes before and after the contact were visually confirmed, the mixed solution before the contact was colorless and transparent, and the mixed solution after the contact was cloudy.

The result is shown in FIG. FIG. 9 is a graph showing the weight of the precipitate formed in the mixed solution due to the contact with the carbon dioxide. In FIG. 9, the vertical axis represents the weight (g) of the precipitate per test tube. The weight value of the precipitate was the average value of the measured values of a total of 6 samples. As shown in FIG. 9, as a result of bringing carbon dioxide into contact with the mixed solution after electrolysis, the precipitate was formed.

Next, as a reference experiment, the following experiment was conducted. As the container, the pipe described in Reference Example 8 described later was used. 200 ml of the electrolyzed solution (the sodium chloride solution after energization) was placed in the pipe, and the electrolyzed solution was brought into contact with the electrolyzed solution by bubbling air in the same manner using the bubbling device. After the contact, the carbon dioxide concentration of the gas in the upper space (height of about 14 cm) of the pipe was measured using a carbon dioxide monitor (RI-85, manufactured by RIKEN KEIKI). Moreover, the carbon dioxide concentration of the air was measured in the same manner.

The result is shown in FIG. FIG. 10 is a graph showing the carbon dioxide concentration in the pipe after the contact. In FIG. 10, the vertical axis shows the carbon dioxide concentration (PPM), and the horizontal axis shows the air (Air) and the gas (Electrolyzed Water) in the upper space of the pipe after the contact from the left. The carbon dioxide concentration value was taken as the average value of the measured values of a total of 3 samples. As shown in FIG. 10, the contact greatly reduced the carbon dioxide concentration in the pipe to zero.

Next, the experiment was carried out in the same manner except that the mixed air having a carbon dioxide concentration of 12 to 18% by mixing the carbon dioxide with the air was used instead of the air.

The result is shown in FIG. FIG. 11 is a graph showing the carbon dioxide concentration in the pipe after the contact. In FIG. 11, the vertical axis represents the carbon dioxide concentration (%), and the horizontal axis represents the mixed air (CO2) and the gas (Electrolyzed Water) in the upper space of the pipe after the contact from the left. The carbon dioxide concentration value was taken as the average value of the measured values of a total of 5 samples. As shown in FIG. 11, the average value of the carbon dioxide concentration in the mixed air was 15%, whereas the contact reduced the average value of the carbon dioxide concentration in the pipe to 4%.

Furthermore, the following experiments were carried out under different conditions. Electrolysis was performed by placing 1 L of the 10% sodium chloride solution in the container of the electrolyzer and energizing for 20 hours using the power supply. The conditions for electrolysis were 9.64V and 0.92A at the start of energization, and 9.62V and 1.2A at 20 hours after energization. Then, the electrolyzed liquid in the container was brought into contact with the electrolyzed liquid by bubbling air using the bubbling device.

As a result, the carbon dioxide concentration in the air was 458 PPM, but the contact reduced the carbon dioxide concentration in the pipe to 80 PPM. The reason why the carbon dioxide concentration did not become zero after the contact was that the concentration of sodium hydroxide was low and the height of the liquid level of the electrolyzed liquid was higher than that when the pipe was used. It is possible that it was low.

As described above, it was confirmed that calcium carbonate was formed by adding calcium chloride after electrolyzing the sodium chloride solution under different conditions.

[Example 3]
It was confirmed that the adhesion of the reaction product to the insertion end can be suppressed by coating the insertion end of the gas-liquid mixing means with a water repellent.

After spraying the air stone included in the set of the bubbling device according to the second embodiment several times with a fluororesin-based waterproof spray (product name Loctite, product number DBS-422, manufactured by Henkel Japan Ltd.). The coating treatment was performed by allowing the mixture to stand for about 30 minutes. After that, the bubbling device (hereinafter, also referred to as “processed bubbling device”) was assembled. Using the untreated air stone as a control, the bubbling device (hereinafter, also referred to as “control bubbling device”) was assembled in the same manner.

An equal amount of 0.1 N sodium hydroxide solution and 0.1 mol / L calcium chloride solution were mixed to prepare a mixed solution. The sodium hydroxide solution was prepared by diluting a 1N sodium hydroxide solution (manufactured by Wako Pure Chemical Industries, Ltd.) with distilled water.

As a container, a plastic box (commercially available) having a volume of 1.85 L was used. 1 L of the mixed solution was placed in the container, and the treated bubbling device and the control bubbling device were used to bring the mixture into contact with each other by bubbling air for 24 hours.

After the contact, the air stone was operated in the air for about 1 minute to remove water contained in the internal space of the air stone. Further, the air stone was removed from the tube and allowed to stand at room temperature for 1 day or more to completely remove the water remaining in the internal space of the air stone. Then, the weight of the air stone was measured, and the weight of the air stone before the contact was subtracted from the weight of the air stone after the contact to calculate the amount of calcium carbonate adhered as a reaction product. .. It was separately confirmed that, of the reaction products, sodium chloride did not form a precipitate at the concentration in this experiment.

The result is shown in FIG. FIG. 12 is a graph showing the weight of calcium carbonate adhering to the air stone. In FIG. 12, the vertical axis shows the weight (g) of calcium carbonate per air stone, and the horizontal axis shows the control and the treated (fluororesin-processed) from the left. The weight value of the calcium carbonate was taken as the average value of the measured values of a total of 4 samples. As shown in FIG. 12, the coating-treated air stone had a significantly reduced amount of adhesion as compared with the control.

As described above, it was confirmed that the adhesion of the reaction product to the insertion end can be suppressed by coating the insertion end of the gas-liquid mixing means with a water repellent.

[Example 4]
It was confirmed that by coating the insertion end of the gas-liquid mixing means with a water repellent, the adhesion of the reaction product to the insertion end can be suppressed even after contact for a longer period of time. In addition, the reaction products in the mixed solution were filtered off.

The air stone was coated in the same manner as in Example 3 except that an air stone (diameter 3 cm, product name Air ball M size, manufactured by Pet one) was used as the air stone. Then, the bubbling device and the control bubbling device were assembled in the same manner as in Example 3.

A mixed solution containing 0.05 N sodium hydroxide and 0.05 mol / L calcium chloride was prepared in the same manner as in Example 3.

In the same manner as in Example 3, 1 L of the mixed solution was placed in the container and brought into contact with each other by bubbling air for 24 hours using the treated bubbling device and the control bubbling device, respectively. .. After that, the mixed solution was replaced with a new solution, and the mixture was contacted by bubbling air for 24 hours. After the contact, it is possible to confirm with the naked eye that calcium carbonate, which is a reaction product, is adhered to the wall surface, the bottom of the container, the uneven surface of the air stone, the internal space, and the like. did it. On the other hand, no obvious white turbidity was observed in the mixed solution.

After the contact, the air stone was operated in the air for about 2 minutes to remove water contained in the internal space of the air stone. Further, the air stone was removed from the tube and allowed to stand at room temperature for 1 to 12 days to completely remove the water remaining in the internal space of the air stone. Then, the weight of the air stone was measured, and the weight of the air stone before the contact was subtracted from the weight of the air stone after the contact to calculate the amount of calcium carbonate adhered as a reaction product. ..

The results are shown in FIGS. 13 and 14. FIG. 13 is a photograph of the air stone after the contact. In FIG. 13, the left shows the control and the right shows the processed air stone. As shown in FIG. 13, the coated air stone had a reduced amount of adhesion as compared with the control.

FIG. 14 is a graph showing the weight of calcium carbonate adhering to the air stone. In FIG. 14, the vertical axis shows the weight (g) of calcium carbonate per air stone, and the horizontal axis shows the control (untreated) and the treated (treated) from the left. The weight value of the calcium carbonate was taken as the average value of the measured values of a total of 3 samples. As shown in FIG. 14, the coated air stone had a reduced amount of adhesion as compared with the control.

Next, the reaction product was filtered off from the mixed solution after the contact. As a filter, an unbleached coffee filter (manufactured by Kanae Paper Works Co., Ltd.) was used and installed in a funnel of a general shape.

By scraping the inside of the container by an operator with respect to the container containing the mixed solution after the contact, the fixed reaction product is contained in the mixed solution. Then, the whole amount (1 L) of the mixed solution was passed through the filter over several minutes.

As a result, the entire amount of the mixed solution could be passed through the filter without clogging. Then, it was possible to visually confirm that the residue of the reaction product was present on the filter.

As described above, it can be confirmed that by coating the insertion end portion of the gas-liquid mixing means with a water repellent, the adhesion of the reaction product to the insertion end portion can be suppressed even after contact for a longer period of time. rice field. In addition, the reaction products in the mixed solution could be filtered out.

[Reference example 1]
In the container, contacting by bubbling sodium hydroxide (NaOH), and a mixture containing calcium chloride (CaCl _2), and a gas containing carbon dioxide (CO _2), and the gas in the liquid mixture By doing so, it was confirmed that carbon dioxide could be fixed.

A 1N sodium hydroxide solution (manufactured by Wako Pure Chemical Industries, Ltd.) was diluted with distilled water so as to be 0.01, 0.02, 0.1, 0.2, and 0.4N, respectively, to prepare a sodium hydroxide solution having each of the above concentrations. .. Further, a 1 mol / L calcium chloride solution (manufactured by Wako Pure Chemical Industries, Ltd.) was diluted with distilled water so as to be 0.01, 0.02, 0.1, 0.2, and 1 (undiluted) mol / L, respectively, and each of the above was prepared. A concentrated calcium chloride solution was prepared.

3 mL of the sodium hydroxide solution of each concentration and 3 mL of the calcium chloride solution of 0.1 mol / L were put into a 10 mL test tube and mixed, and carbon dioxide (CO ₂ 100%, Koike) was added to the mixed solution. (Made by Kogyo Co., Ltd.) was brought into contact by bubbling. The bubbling ejected carbon dioxide from the tip of a pastur pipette. The bubbling condition was 10 seconds (about 20 cm ³ ). After the contact, the mixed solution was centrifuged at 3,000 rpm for 10 minutes. Then, the weight of the test tube was measured before and after the contact, and the difference in the weight before and after the contact was calculated as the amount of precipitation. As will be described later, when a precipitate was formed before the contact with carbon dioxide was performed, the contact was carried out after removing the precipitate.

The results are shown in FIGS. 15 and 16. FIG. 15 is a photograph of a mixed solution containing 0.05 N sodium hydroxide and 0.05 mol / L calcium chloride before and after the contact with carbon dioxide, and the left side in the figure is before the contact. The right side shows the state of the test tube after the contact. As shown in FIG. 15, contact with carbon dioxide produced a white precipitate of _{calcium carbonate (CaCO 3) in the mixed solution.} In the mixed solution, cloudiness occurred before the bubbling for 10 seconds was completed.

FIG. 16 is a graph showing the weight of the precipitate formed in the mixed solution due to the contact with the carbon dioxide. In FIG. 16, the vertical axis represents the weight (g) of the precipitate per test tube, and the horizontal axis represents the sodium hydroxide concentration (N) in the mixture. The value of the weight of the precipitate was taken as the average value of the measured values of a total of 5 samples for each sample of the mixed solution. As shown in FIG. 16, as a result of contacting carbon dioxide at a sodium hydroxide concentration of 0.01 N or more, the precipitate was formed. Then, when the concentration was 0.05 N, the amount of the precipitate was greatly increased, and when the concentration was 0.1 N, the amount of the precipitate was the maximum. On the other hand, when the concentration was 0.2 N, the amount of the precipitate decreased as compared with the value at 0.1 N. It was confirmed that more carbon dioxide could be fixed at the concentrations of 0.05 to 0.2 N and 0.05 to 0.1 N.

When the sodium hydroxide concentration was 0.2 N, a white precipitate was formed in the mixed solution before the contact with carbon dioxide. This white precipitate is considered to be _{calcium hydroxide (Ca (OH) 2} ) produced by the reaction of calcium chloride with a high concentration of sodium hydroxide. Therefore, the reason why the amount of the precipitate decreased when the concentration was 0.2 N was that calcium hydroxide was generated by the reaction of calcium chloride and high-concentration sodium hydroxide, and the synthesis of calcium carbonate by the contact was carried out. This is probably because the amount has decreased.

Next, 3 mL of the sodium hydroxide solution of 0.1 N and 3 mL of the calcium chloride solution having each concentration were added and mixed, and the contact was carried out in the same manner except that the mixed solution was prepared.

The result is shown in FIG. FIG. 17 is a graph showing the weight of the precipitate formed in the mixed solution due to the contact with the carbon dioxide. In FIG. 17, the vertical axis represents the weight (g) of the precipitate per test tube, and the horizontal axis represents the calcium chloride concentration (mol / L) in the mixture. The value of the weight of the precipitate was taken as the average value of the measured values of a total of 5 samples for each sample of the mixed solution. As shown in FIG. 17, as a result of contacting carbon dioxide at all calcium chloride concentrations, the precipitate was formed. Then, when the concentration was 0.05 mol / L, the amount of the precipitate was greatly increased, and when the concentration was 0.1 mol / L, the amount of the precipitate was the maximum. It was confirmed that more carbon dioxide can be fixed when the calcium chloride concentration is 0.05 to 0.5 mol / L.

When the calcium chloride concentration was 0.2 to 0.5 mol / L, a white precipitate was formed in the mixed solution before the contact with carbon dioxide. Then, this white precipitate disappeared by adding carbon dioxide at the contact. On the other hand, when the calcium chloride concentration was 0.1 mol / L and 0.05 mol / L, the formation of a precipitate was observed in the mixed solution, and the precipitate did not disappear even when the contact was carried out.

As described above, carbon dioxide is generated by bringing a mixed solution containing sodium hydroxide and calcium chloride and a gas containing carbon dioxide into contact with each other in the container by bubbling the gas into the mixed solution. It was confirmed that it could be fixed.

[Reference example 2]
A solution containing sodium hydroxide (NaOH) and a solution containing calcium chloride (CaCl ₂ ) were mixed, and it was confirmed that the concentration of sodium hydroxide was related to the presence or absence of precipitation formation.

A 3 mL sodium hydroxide solution was placed in a 10 mL test tube, and then a 3 mL calcium chloride solution was added to prepare a mixed solution. In the mixed solution, the sodium hydroxide concentration was 0.2N and 0.25N, and the calcium chloride concentration was 0.05 mol / L. After the mixing, a photograph of the test tube was taken.

The result is shown in FIG. FIG. 18 is a photograph of a mixed solution containing sodium hydroxide and calcium chloride. In the figure, when the four test tubes on the left are 0.2N sodium hydroxide, the four test tubes on the right are used. However, the case where 0.25 N sodium hydroxide is used is shown. As shown in FIG. 18, when 0.25 N sodium hydroxide was used, cloudiness due to the formation of _{calcium hydroxide (Ca (OH) 2) was confirmed in all the four mixed solutions tested.} On the other hand, when 0.2 N sodium hydroxide was used, a slight cloudiness occurred in the mixed solution in one of the four test tubes in which the experiment was conducted, but in the remaining three mixed solutions, the mixed solution was slightly clouded. No cloudiness was confirmed.

From the above, it was confirmed that the solution containing sodium hydroxide and the solution containing calcium chloride were mixed, and the concentration of sodium hydroxide was related to the presence or absence of precipitation formation.

[Reference example 3]
Confirmed that carbon dioxide can be fixed by contacting a mixture containing sodium hydroxide and calcium chloride and a gas containing carbon dioxide in a container in a state where the mixture is allowed to stand or shaken. did.

An equal amount of 0.1 N sodium hydroxide solution and 0.1 mol / L calcium chloride solution were mixed to prepare a mixed solution. After equilibrating the inside of a general-shaped PET bottle (commercially available) having a volume of 2 L with the atmosphere, 10 mL of the mixed solution was placed in the PET bottle. The PET bottle was allowed to stand upright with the bottom surface facing down, and the mixed solution was brought into contact with carbon dioxide. The PET bottle is used at 0 minutes (immediately after the contact), 15 minutes, 30 minutes, and 60 minutes after the contact, and after the contact overnight, using a carbon dioxide monitor (RI-85, manufactured by RIKEN KEIKI). The carbon dioxide concentration inside was measured.

The result is shown in FIG. FIG. 19 is a graph showing the carbon dioxide concentration in the PET bottle after the contact. In FIG. 19, the vertical axis represents the carbon dioxide concentration (PPM), and the horizontal axis represents the elapsed time (minutes) after the contact. The carbon dioxide concentration value was taken as the average value of the measured values of a total of 4 samples for 0 minutes (immediately after the contact), 15 minutes, 30 minutes, and 60 minutes after the contact. After the overnight contact, the measured values of a total of 6 samples were 0 PPM. As shown in FIG. 19, the contact reduced the carbon dioxide concentration in the PET bottle according to the elapsed time after the contact. Further, since the value of the carbon dioxide concentration became 0 PPM after the contact in the overnight, it was found that even a low concentration of carbon dioxide can be fixed according to the present invention.

Next, instead of the PET bottle, an octagonal pillar plastic bottle having the shape shown in FIG. 20 was used, and the octagonal pillar plastic bottle was laid on its side with the side surface facing down, or left standing. The contact was carried out for 5 minutes in the same manner except that the octagonal pillar plastic bottle was shaken in the state of being laid on its side. FIG. 20A is a side view of the octagonal pillar plastic bottle, and FIG. 20B is a view of the octagonal pillar plastic bottle seen from the bottom surface. The shaker was shaken using a shaker (BR-21UM, manufactured by TAITEK) under the condition of 120 rpm.

The result is shown in FIG. FIG. 21 is a graph showing the carbon dioxide concentration in the octagonal pillar plastic bottle after the contact. In FIG. 21, the vertical axis shows the carbon dioxide concentration (PPM), and the horizontal axis shows from the left immediately after the contact (0 minutes), after the contact by the stationary state, and after the contact by the shaking. The carbon dioxide concentration value was taken as the average value of the measured values of a total of 4 samples. As shown in FIG. 21, the contact by the shaking reduced the carbon dioxide concentration in the octagonal pillar plastic bottle as compared with immediately after the contact. In particular, it can be confirmed that the contact by the shaking greatly reduces the carbon dioxide concentration in the octagonal pillar plastic bottle to about 1/6 as compared with immediately after the contact, and more carbon dioxide can be fixed. rice field.

As described above, the contact by shaking reduced the carbon dioxide concentration more significantly than the case where the contact by standing still was performed. It is considered that the reason for this is that the surface area of the mixture has increased due to the shaking, and it has become possible to come into contact with the gas containing more carbon dioxide. Further, it is considered that the surface area of the mixed liquid is further increased because the bottom of the octagonal pillar plastic bottle is flatter and shorter than that of the PET bottle having a general shape.

Next, the contact was performed by changing the shaking conditions. Instead of the octagonal pillar plastic bottle, a PET bottle having a volume of 2 L and having the general shape was used. Twelve hours before the contact, the lid of the PET bottle was opened, the tip of the Pasteur pipette was inserted into the mouth of the PET bottle, and carbon dioxide was injected from the tip. Then, after putting 50 mL of the mixed solution into the PET bottle, the mixture was vigorously shaken by an adult male's hand 1 to 6 times with one shaking for 30 seconds. The first contact by the shaking is performed immediately after the contact, and the second to sixth contacts by the shaking are performed 2 minutes, 5 minutes, and 15 minutes, respectively, immediately after the contact. It was performed after the lapse, 30 minutes, and 60 minutes. Then, after the 1 to 6 times of the contact, the carbon dioxide concentration was measured using a carbon dioxide detector (XP-3140, manufactured by COSMO), respectively.

Further, after the sixth contact, 50 mL of the mixed solution was further added, and the mixture was vigorously shaken for 30 seconds, and then the concentration of carbon dioxide was measured. Then, after standing for another 24 hours, the concentration of carbon dioxide was measured. After allowing to stand for 24 hours, 50 mL of the mixed solution was further added, and the mixture was vigorously shaken for 30 seconds, and then the concentration of carbon dioxide was measured.

The result is shown in FIG. FIG. 22 is a graph showing the carbon dioxide concentration in the PET bottle after the contact. In FIG. 22, the vertical axis indicates the carbon dioxide concentration (%), and the horizontal axis indicates the carbon dioxide concentration (%) from the left, immediately after the contact (0 minutes), after the first contact by the shaking (30 seconds), and the second contact. After the contact by shaking (2 minutes), after the third contact by the shaking (5 minutes), after the fourth contact by the shaking (15 minutes), after the fifth contact by the shaking (30 minutes), The following shows after the sixth shaking (60 minutes), after adding the mixed solution, allowing to stand for 24 hours, and after re-adding the mixed solution. The carbon dioxide concentration value was taken as the average value of the measured values of a total of 5 samples. As shown in FIG. 22, after the first contact (30 seconds), the concentration of carbon dioxide was significantly reduced as compared with immediately after the contact (0 minutes). Then, after the 2nd to 6th contacts, the concentration of carbon dioxide gradually decreased. On the other hand, the addition of the mixture caused a rapid further decrease in carbon dioxide concentration. A significant decrease in carbon dioxide concentration was also observed with the re-addition of the mixture. As described above, it was confirmed that even in the state of high carbon dioxide concentration, the addition of the mixed solution again causes a decrease in carbon dioxide concentration.

Further, the contact was performed by changing the shaking conditions. Instead of the PET bottle, a plastic box (commercially available) having a volume of 1.85 L shown in FIG. 31 was used. In addition, in FIG. 31, the inside of the plastic box is shown perspectively. After putting 500 mL of the sodium hydroxide solution of 0.1 N and 500 mL of the calcium chloride solution of 0.1 mol / L in the plastic box, a hand mixer (HM-20, 60 W, manufactured by TOSHIBA) was used. The contact was made by making a full rotation (number 3, "bubbling-bubbling egg whites finely" mode). Then, the carbon dioxide concentration in the plastic box was measured using the carbon dioxide monitor. Approximately 2 minutes after the start of the contact, it was confirmed that the carbon dioxide concentration became almost constant, and the contact was terminated. The measured value of the carbon dioxide concentration at the end of the contact was acquired. As a control, the carbon dioxide concentration in the air outside the plastic box was measured.

The result is shown in FIG. FIG. 32 is a graph showing the carbon dioxide concentration in the plastic box after the contact. In FIG. 32, the vertical axis indicates the carbon dioxide concentration (PPM), and the horizontal axis indicates the control and the end of the contact from the left. The carbon dioxide concentration value was taken as the average value of the measured values of a total of 3 samples. As shown in FIG. 32, after the contact, the concentration of carbon dioxide was significantly reduced as compared to the control.

As described above, carbon dioxide is produced by bringing the mixture containing sodium hydroxide and calcium chloride into contact with the gas containing carbon dioxide in the container in a state where the mixture is allowed to stand or shaken. It was confirmed that it can be fixed.

[Reference example 4]
It was confirmed that carbon dioxide can be fixed by contacting a mixture containing sodium hydroxide and calcium chloride and a gas containing carbon dioxide in a container in a atomized state.

A mixed solution containing the sodium hydroxide and the calcium chloride was prepared in the same manner as in Reference Example 3. Using a PET bottle having a general shape having a volume of 2 L, the inside of the PET bottle was equilibrated with the atmosphere in the same manner as in Reference Example 3. Then, about 4 mL of the mixed solution was sprayed onto the PET bottle 10 times at 5-second intervals using a sprayer (commercially available) to bring the mixed solution into contact with carbon dioxide. For the contact, as shown in FIG. 23, the PET bottle was used sideways with the side surface facing down, and the spray was performed in the horizontal direction. Immediately after the contact, the carbon dioxide concentration in the PET bottle was measured in the same manner as in Reference Example 3.

The result is shown in FIG. FIG. 24 is a graph showing the carbon dioxide concentration in the PET bottle after the contact. In FIG. 24, the vertical axis shows the carbon dioxide concentration (PPM), and the horizontal axis shows from the left immediately after the contact (0 minutes) and after the contact by the spray. The carbon dioxide concentration value was taken as the average value of the measured values of a total of 4 samples. As shown in FIG. 24, the contact by the spray greatly reduced the carbon dioxide concentration in the PET bottle to about 1/6 as compared with immediately after the contact.

As described above, the carbon dioxide concentration was greatly reduced in a short time by the contact by the spray. It is considered that the reason for this is that by contacting the mixed solution in a mist state, the surface area of the mixed solution is greatly increased, and it becomes possible to contact the gas containing more carbon dioxide.

Next, the contact was performed by changing the spraying conditions. The contact means for making the contact was produced as follows. As shown in FIG. 25, two boxes (commercially available) which are milk cartons are connected in an L shape, and holes are made in two places on the side surface of the box at the bottom by partially cutting the holes. An air injection part and a carbon dioxide injection part were provided by inserting a silicon tube from the inside. Further, a hole was similarly formed in the upper surface of the lower box so that the mixed solution could be sprayed into the inside of the box from the sprayer. The connecting parts of the upper and lower boxes were made to allow carbon dioxide to rise from the lower box to the upper box by opening large cuts, respectively. A gauze layer was provided on the connecting portion with a quadruple gauze (commercially available). The upper surface of the upper box was opened. Further, a hole was similarly formed on the side surface of the upper box, and a nozzle of a carbon dioxide concentration detector (XP-3140, manufactured by COSMO) was installed.

The flow rate of air from the air injection section is about 100 cm ³ / sec, and the flow rate of carbon dioxide from the carbon dioxide injection section is 10 cm ³ / sec, and injection is performed until the measured value of carbon dioxide concentration becomes constant. went. Then, the mixed solution was sprayed from the atomizer 10 times in a row. The spray amount of the mixed solution was about 4 mL in total after 10 times. Approximately 20 seconds after the spraying, the measured value of carbon dioxide concentration became the lowest value.

The result is shown in FIG. FIG. 26 is a graph showing the carbon dioxide concentration in the box when the measured value of carbon dioxide reaches the minimum value about 20 seconds after the contact. In FIG. 26, the vertical axis shows the carbon dioxide concentration (%), and the horizontal axis shows from the left, before the contact and after the contact by the spray. The carbon dioxide concentration value was taken as the average value of the measured values of a total of 10 samples. As shown in FIG. 26, the contact by the spray reduced the carbon dioxide concentration in the box as compared with that before the contact.

As described above, it was confirmed that carbon dioxide can be absorbed by the mixed solution even when the contact means is an open system. Furthermore, since the amount of the sprayed mixture was as small as about 4 mL, it was found that even if the amount of the mixture was small, the concentration of high-concentration carbon dioxide could be sufficiently reduced. From this, it can be said that the reaction system of the present invention has extremely excellent reaction efficiency.

As described above, carbon dioxide can be fixed by bringing the mixture containing sodium hydroxide and calcium chloride into contact with the gas containing carbon dioxide in the state of atomizing the mixture in the container. Was confirmed.

[Reference example 5]
After the first contact step of contacting the solution containing sodium hydroxide (NaOH) with the _{gas containing carbon dioxide (CO 2} ) and the first contact step, calcium chloride (CaCl ₂ ) is added to the solution. It was confirmed that carbon dioxide could be fixed by the second contact step of adding.

As a solution containing sodium hydroxide, a 1N sodium hydroxide solution (manufactured by Wako Pure Chemical Industries, Ltd.) was used. Further, a 1 mol / L calcium chloride solution (manufactured by Wako Pure Chemical Industries, Ltd.) was diluted with distilled water to prepare a 0.1 mol / L calcium chloride solution.

A 5 ml 1N sodium hydroxide solution was placed in a 10 mL test tube and _{contacted with the solution by bubbling carbon dioxide (CO 2} 100%, manufactured by Koike Kogyo Co., Ltd.) (first contact step). ). The bubbling ejected carbon dioxide from the tip of a pastur pipette. The bubbling conditions were 2 cm ³ / sec and 40 seconds. The size of the bubble in the bubbling was visually measured by comparing it with a scale and found to be on the order of millimeters to centimeters.

Next, the solution after the first contact was diluted with distilled water to a predetermined concentration (0.1N and 0.05N). 3 mL of the diluted solution was placed in a 10 mL test tube, and 3 ml of the 0.1 mol / L calcium chloride solution was added to the solution (second contact step). After the contact, the mixed solution after the addition was centrifuged at 3,000 rpm for 10 minutes. Then, the weight of the test tube was measured before and after the contact, and the difference in the weight before and after the contact was calculated as the amount of precipitation.

In addition, the following experiment was conducted to see the effect of sodium hydroxide concentration on the absorption of carbon dioxide. The 1N sodium hydroxide solution was diluted with distilled water to the predetermined concentrations (0.1N and 0.05N). 3 ml of the sodium hydroxide solution having the predetermined concentration was placed in a 10 mL test tube, and the solution was contacted by bubbling carbon dioxide (first contact step). The bubbling conditions were 2 cm ³ / sec and 20 seconds. Then, 3 ml of the calcium chloride solution of 0.1 mol / L was added to the solution (second contact step). After the addition, the amount of precipitation was calculated in the same manner.

These results are shown in FIG. FIG. 27 is a graph showing the weight of the precipitate formed in the mixed solution due to the contact with the carbon dioxide. In FIG. 27, the vertical axis shows the weight (g) of the precipitate per test tube, the horizontal axis shows each experimental condition, and the graph on the left shows the first step with 1N of the sodium hydroxide solution. The result (“High Concentration”) was shown, and the graph on the right shows the result (“Low Concentration”) of the first step using the diluted sodium hydroxide solution. The value of the weight of the precipitate was taken as the average value of the measured values of the four samples. As shown in FIG. 27, as a result of performing the first contact step and the second contact step, the precipitation occurred regardless of the concentration of the first contact step. Moreover, when the first contact step was carried out at a high concentration, the amount of the precipitate was larger.

Furthermore, it was confirmed that sodium hydrogen carbonate (NaHCO ₃ ) and sodium carbonate (Na ₂ CO ₃ ) produced in the first step react with calcium chloride in the second step to cause precipitation.

A 0.5 mol / L calcium chloride solution was prepared in the same manner as described above. 1 ml of 1 N sodium hydrogen carbonate solution (manufactured by Wako Pure Chemical Industries, Ltd.), 1 ml of distilled water, and 2 ml of the calcium chloride solution of 0.5 mol / L were placed in a 10 mL test tube and mixed using a vortex mixer. Then, for the generated precipitate, the amount of precipitate was calculated in the same manner as described above.

Further, in the same manner, 2 ml of a 0.5 mol / L sodium carbonate solution (manufactured by Wako Pure Chemical Industries, Ltd.) and 2 ml of the 0.5 mol / L calcium chloride solution were mixed, and the amount of precipitate was calculated for the produced precipitate.

The result is shown in FIG. FIG. 28 is a graph showing the weight of the precipitate formed in the mixed solution due to the contact with the carbon dioxide. In FIG. 28, the vertical axis represents the weight (g) of the precipitate per test tube, and the horizontal axis represents each experimental condition. The weight value of the precipitate was the average value of the measured values of a total of 4 samples for each of the samples. As shown in FIG. 28, the sodium hydrogen carbonate solution and the sodium carbonate solution each produced a precipitate by reaction with the calcium chloride solution.

From the above, after the first contact step of contacting the solution containing sodium hydroxide with the gas containing carbon dioxide and the first contact step, calcium chloride is added to the solution, and further, after the addition. It was confirmed that carbon dioxide can be fixed by the second contact step of bringing the mixed solution of carbon dioxide into contact with the gas containing carbon dioxide. It was also confirmed that the sodium hydrogen carbonate and sodium carbonate produced in the first step react with calcium chloride in the second step to cause precipitation.

[Reference example 6]
It was confirmed that carbon dioxide can be fixed even if the concentrations of the sodium hydroxide solution and the calcium chloride solution are changed.

A 1N sodium hydroxide solution was used in the same manner as in Reference Example 5. Further, a 5N sodium hydroxide solution (manufactured by Wako Pure Chemical Industries, Ltd.) was used as the solution containing the sodium hydroxide. Further, in the same manner as in Reference Example 5, 0.1 mol / L and 0.5 mol / L calcium chloride solutions were prepared.

Using the sodium hydroxide solution of 1N and 5N and the calcium chloride solution of 0.1 mol / L and 0.5 mol / L in the same manner as in Reference Example 5, the first contact step and the second contact step. A contact process was performed. However, only when the 5N sodium hydroxide solution was used, the bubbling time in the first contact step was set to 50 seconds instead of 20 seconds. Then, the amount of precipitation was calculated in the same manner as in Reference Example 5.

The result is shown in FIG. FIG. 29 is a graph showing the weight of the precipitate formed in the mixed solution due to the contact with the carbon dioxide. In FIG. 29, the vertical axis shows the weight (g) of the precipitate per test tube, the horizontal axis shows each experimental condition, and the graph on the left shows the first step in 1N of the sodium hydroxide solution. The graph on the right shows the result of performing the first step using the sodium hydroxide solution of 5N, and in each of them, the left shows the calcium chloride solution of 0.1 mol / L. As a result of using, the right shows the result of using the calcium chloride solution of 0.5 mol / L. The weight value of the precipitate was the average value of the measured values of a total of 5 samples for each of the samples. As shown in FIG. 29, the precipitation occurred regardless of the concentration of the sodium hydroxide solution and the calcium chloride solution. As a result of setting the concentration of the sodium hydroxide solution to 1N and 5N, almost the same value was obtained between the two. As a result of adjusting the concentrations of the calcium chloride solution to 0.1 mol / L and 0.5 mol / L, at 0.5 mol / L, the concentration of the sodium hydroxide solution was higher than that at the case of 0.1 mol / L. , The amount of precipitation was about half the value. It was confirmed that more carbon dioxide could be fixed by using the 0.1 mol / L calcium chloride solution.

From the above, it was confirmed that carbon dioxide can be fixed even if the concentrations of the sodium hydroxide solution and the calcium chloride solution are changed.

[Reference Example 7]
It was confirmed that carbon dioxide can be fixed even if the contact time with the gas containing carbon dioxide in the first contact step is changed. Further, the mixed solution containing sodium hydroxide and calcium chloride was brought into contact with the gas containing carbon dioxide without performing the first contact step and the second contact step, and the results were compared.

A 1N sodium hydroxide solution was used in the same manner as in Reference Example 5. Moreover, the said calcium chloride solution of 0.1 mol / L was prepared.

The first contact step was performed in the same manner as in Reference Example 5 except that the bubbling conditions were set to 5, 10, 20, 30, and 60 seconds.

Next, 9 mL of distilled water was added to the solution after the first contact to dilute it so that the concentration was about 0.1 N (approximate value based on the initial concentration). 3 mL of the diluted solution was placed in a 10 mL test tube, and 3 ml of the 0.1 mol / L calcium chloride solution was added to the solution (second contact step). After the contact, the mixed solution was centrifuged in the same manner as in Reference Example 5. Then, the amount of precipitation was calculated in the same manner as in Reference Example 5.

Moreover, as a comparative example, the following experiment was carried out. The 1N sodium hydroxide solution was diluted with distilled water to 0.1N. 3 ml of 0.1 N sodium hydroxide solution and 3 ml of 0.1 N calcium chloride solution are placed in a 10 mL test tube and mixed, and carbon dioxide is bubbled into the mixed solution in the same manner as described above. By doing so, they were brought into contact with each other. After the addition, the amount of precipitation was calculated in the same manner.

These results are shown in FIG. FIG. 30 is a graph showing the weight of the precipitate formed in the mixed solution due to the contact with the carbon dioxide. In FIG. 30, the vertical axis represents the weight (g) of the precipitate per test tube, the horizontal axis represents the bubbling time, and the graph on the left shows the first contact step and the second contact step, respectively. The result of the contact step is shown, and the graph on the right shows the result of the comparative example. The value of the weight of the precipitate was taken as the average value of the measured values three times in total. As shown in FIG. 30, as a result of performing the first contact step and the second contact step, the precipitation occurred at any bubbling time. Bubbling for 5 to 30 seconds gave about the same amount of precipitation. Even after bubbling for 60 seconds, a sufficient amount of precipitation was obtained, although it decreased slightly. In the case of the comparative example, the precipitation occurred in the bubbling for 5 seconds to 10 seconds, but the amount of precipitation was less than half as compared with the result of performing the first contact step and the second contact step. there were. Further, when bubbling for 20 seconds or more was performed, the amount of precipitation was greatly reduced.

From the above, it was confirmed that carbon dioxide can be fixed even if the contact time with the gas containing carbon dioxide in the first contact step is changed. Further, when the first contact step and the second contact step are performed, the mixed solution containing sodium hydroxide and calcium chloride is added without performing the first contact step and the second contact step. It was found that carbon dioxide can be fixed more efficiently than when it is brought into contact with a gas containing carbon dioxide.

[Reference Example 8]
It was confirmed that carbon dioxide can be fixed by contacting a mixture containing sodium hydroxide and calcium chloride with a gas containing carbon dioxide by bubbling the gas into the mixture.

In the same manner as in Reference Example 6, a mixed solution containing 0.05 N of the sodium hydroxide and 0.05 mol / L of the calcium chloride was prepared. 500 ml of the mixed solution is placed in a plastic bottle (commercially available, width 7.5 cm, depth 7.5 cm, height 12 cm), and as shown in FIG. 33, the mixed solution is mixed with a bubbling device (product name) for aquarium organisms. : Bukubuku (assembled air pump, hose, and air stone included in the set), manufactured by Kotobuki Kotobuki Co., Ltd.) was used to bring the air into contact by bubbling. In addition, in FIG. 33, the inside of the plastic bottle is shown perspectively. The bubbling was performed for 9 hours and 12 hours under the condition of ^{20 cm 3 / sec.} The size of the bubble in the bubbling was visually measured by comparing it with a scale and found to be on the order of micrometers to millimeters. After the contact, 5 mL of the mixed solution was obtained, centrifuged at 3,000 rpm for 10 minutes, and then the precipitate was weighed. Further, instead of the air, mixed air having a carbon dioxide concentration of 15% by mixing the carbon dioxide with the air was used, and the experiment was carried out in the same manner except that the bubbling was performed for 1.5 hours.

The result is shown in FIG. FIG. 34 is a graph showing the weight of the precipitate formed in the mixed solution due to the contact with the carbon dioxide. In FIG. 34, the vertical axis represents the weight (g) of the precipitate, and the horizontal axis represents each experimental condition. The value of the weight of the precipitate was taken as the average value of the measured values of a total of 4 samples for each sample of the mixed solution. As shown in FIG. 34, the bubbling of the air and the mixed air caused precipitation. In the bubbling of the air, the amount of precipitation increased with the passage of time.

Next, the experiment was conducted by changing the shape of the container. As the container, a vinyl chloride pipe (commercially available) having a diameter of 40 mm and a height of 50 cm was used instead of the plastic bottle. A pipe cap (commercially available) was attached to one end of the pipe, which is the bottom. FIG. 35 is a schematic view illustrating the form of the pipe. In addition, in FIG. 35, the inside of the pipe is shown perspectively. Further, in the same manner as in Reference Example 5, a 0.1 N sodium hydroxide solution and a 0.1 mol / L calcium chloride solution were prepared. 250 ml of the sodium hydroxide solution and 250 ml of the calcium chloride solution were placed in the pipe and contacted with the mixed solution by bubbling air for about 1 minute in the same manner as described above. After the contact, the carbon dioxide concentration of the gas in the upper space (height of about 14 cm) of the pipe was measured in the same manner as in Reference Example 6. Moreover, the carbon dioxide concentration of the air was measured in the same manner.

The result is shown in FIG. FIG. 36 is a graph showing the carbon dioxide concentration in the pipe after the contact. In FIG. 36, the vertical axis represents the carbon dioxide concentration (PPM), and the horizontal axis represents the air (Air) and the gas (Inner Pipe) in the upper space of the pipe from the left. The carbon dioxide concentration value was taken as the average value of the measured values of a total of 9 samples. As shown in FIG. 36, the contact greatly reduced the carbon dioxide concentration in the pipe.

Next, the experiment was carried out in the same manner except that the mixed air having a carbon dioxide concentration of 10% by mixing the carbon dioxide with the air was used instead of the air.

The result is shown in FIG. 37. FIG. 37 is a graph showing the carbon dioxide concentration in the pipe after the contact. In FIG. 37, the vertical axis shows the carbon dioxide concentration (%), and the horizontal axis shows each experimental condition from the left. The carbon dioxide concentration value was taken as the average value of the measured values of a total of 3 samples. As shown in FIG. 37, the contact reduced the carbon dioxide concentration in the pipe.

Next, the experiment was carried out by changing the amount of the mixed solution. In the same manner as in Reference Example 6, a mixed solution containing 0.05 N of the sodium hydroxide and 0.05 mol / L of the calcium chloride was prepared. 100, 200, 300, 400, and 500 ml of the mixed solution were placed in the pipe and contacted with the mixed solution by bubbling air for 1 to 2 minutes in the same manner as described above. Under each of the above conditions, the heights of the liquid level of the mixed liquid from the bottom surface of the pipe were 7, 14, 22, 29, and 36 cm, respectively. After the contact, the carbon dioxide concentration of the gas in the upper space of the pipe (position about 10 cm from the upper end of the pipe) was measured in the same manner as in Reference Example 6. Moreover, the carbon dioxide concentration of the air was measured in the same manner.

The result is shown in FIG. FIG. 38 is a graph showing the carbon dioxide concentration in the pipe after the contact. In FIG. 38, the vertical axis indicates the carbon dioxide concentration (PPM), and the horizontal axis indicates the height of the air (Control) and the liquid level from the left. The carbon dioxide concentration value was taken as the average value of the measured values of a total of 3 samples. As shown in FIG. 38, the contact greatly reduced the carbon dioxide concentration in the pipe even when the liquid level was 7 cm. Further, as the height of the liquid level (the amount of the mixed liquid) increased, the carbon dioxide concentration further decreased.

Next, the experiment was conducted by changing the form of the contact. In the same manner as in Reference Example 6, a mixed solution containing 0.05 N of the sodium hydroxide and 0.05 mol / L of the calcium chloride was prepared. 500 ml of the mixed solution was placed in the pipe and brought into contact with each other by bubbling air for 1 to 2 minutes in the same manner as described above. On the other hand, in the contact, the same applies except that the air stone connected to the tip of the hose of the bubbling device is removed and air is bubbling directly from the hose (diameter: about 5 mm, made of silicon). , Conducted an experiment. The size of the bubble in the bubbling was visually measured by comparing it with a scale and found to be on the order of millimeters to centimeters. After the contact, the carbon dioxide concentration was measured in the same manner as described above. Moreover, the carbon dioxide concentration of the air was measured in the same manner.

The result is shown in FIG. FIG. 39 is a graph showing the carbon dioxide concentration in the pipe after the contact. In FIG. 39, the vertical axis represents the carbon dioxide concentration (PPM), and the horizontal axis represents the air (Control), bubbling from the air stone (Ball), and bubbling from the hose (Tube) from the left. ) Is shown. The carbon dioxide concentration value was taken as the average value of the measured values of a total of 4 samples. As shown in FIG. 39, bubbling from the air stone significantly reduced the carbon dioxide concentration in the pipe (down to 4.27%). On the other hand, when bubbling from the hose, the carbon dioxide concentration decreased (decreased to 69.49%), but the amount of decrease was smaller than that when bubbling from the air stone. From this, it was found that the small bubble size in the bubbling is important for the absorption of carbon dioxide.

As described above, it was confirmed that carbon dioxide can be fixed by contacting a mixture containing sodium hydroxide and calcium chloride with a gas containing carbon dioxide by bubbling the gas into the mixture. did it.

[Reference example 9]
It was confirmed that carbon dioxide can be absorbed by contacting a solution containing sodium hydroxide with a gas containing carbon dioxide.

The sodium hydroxide solution of 0.05 N was prepared in the same manner as in Reference Example 5. Using a PET bottle having a general shape having a volume of 2 L, the inside of the PET bottle was equilibrated with the atmosphere in the same manner as in Reference Example 6. Then, 10 mL of the sodium hydroxide solution was placed in the PET bottle and allowed to stand so that the solution and carbon dioxide in the atmosphere were brought into contact with each other. 0 minutes (immediately after the contact), 15 minutes, 30 minutes, and 60 minutes after the contact, the carbon dioxide concentration in the PET bottle was measured in the same manner as in Reference Example 6.

The result is shown in FIG. FIG. 40 is a graph showing the carbon dioxide concentration in the PET bottle after the contact. In FIG. 40, the vertical axis represents the carbon dioxide concentration (PPM), and the horizontal axis represents the elapsed time (minutes) after the contact. The carbon dioxide concentration value was taken as the average value of the measured values of a total of 3 samples. As shown in FIG. 40, the contact reduced the carbon dioxide concentration in the PET bottle after 15 minutes, 30 minutes, and 60 minutes as compared with immediately after the contact.

Next, the contact was performed by changing the form of the contact. Instead of the PET bottle, a plastic box (commercially available) having a volume of 2 L shown in FIG. 41 was used. In addition, in FIG. 41, the inside of the plastic box is shown perspectively. After putting 500 mL of the sodium hydroxide solution of 0.1 N into the plastic box, the upper surface of the plastic box was covered with a plastic plate as shown in FIG. 41. The solution was brought into contact with the solution by bubbling air using a bubbling device (product name: Micro bubbler (F-1056-002), manufactured by Front Industry Co., Ltd.). The bubbling was performed under the condition of ^{20 cm 3 / sec.} The size of the bubble in the bubbling was visually measured by comparing it with a scale and found to be on the order of micrometers to millimeters. Then, immediately after the start of the contact (0 minutes), 5 minutes, 10 minutes, and 15 minutes, the carbon dioxide concentration in the upper space in the plastic box was measured using the carbon dioxide monitor.

The result is shown in FIG. FIG. 42 is a graph showing the carbon dioxide concentration in the plastic box after the contact. In FIG. 42, the vertical axis indicates the carbon dioxide concentration (PPM), and the horizontal axis indicates the carbon dioxide concentration (PPM) from the left, immediately after the start of the contact (0 time), 5 minutes (5 min), 10 minutes (10 min), and. It shows after 15 minutes (15 min). As shown in FIG. 42, the carbon dioxide concentration in the plastic box decreased significantly 5 minutes after the start of the contact. After that, the carbon dioxide concentration gradually decreased according to the elapsed time after the contact.

Next, the experiment was conducted by changing the shape of the container. As the container, the pipe described in Reference Example 8 was used instead of the plastic bottle. 200 ml of the sodium hydroxide solution of 0.1 N was placed in the pipe, and the mixed air having a carbon dioxide concentration of 10% was contacted with the solution by bubbling in the same manner as described above. Then, the carbon dioxide concentration in the upper space in the pipe was measured using the carbon dioxide monitor continuously until 5 minutes after the start of the contact. Further, the carbon dioxide concentration was measured up to 2 minutes in the same manner except that the 1N sodium hydroxide solution was used.

The result is shown in FIG. FIG. 43 is a graph showing the carbon dioxide concentration in the pipe 2 minutes after the start of contact. In FIG. 43, the vertical axis represents the carbon dioxide concentration (PPM), and the horizontal axis represents the concentration of the sodium hydroxide solution. As shown in FIG. 43, when the 0.1 N sodium hydroxide solution was used, the carbon dioxide concentration in the pipe rapidly decreased immediately after the start of the contact, and after 2 minutes, the value immediately after the start of the contact. Compared with, it decreased to 7.5%. After that, the concentration was a substantially constant value from the start of the contact to 5 minutes later. Further, when the 1N sodium hydroxide solution was used, the carbon dioxide concentration in the pipe also decreased rapidly immediately after the start of the contact and became "0" after 2 minutes.

As described above, it was confirmed that carbon dioxide can be absorbed by bringing the solution containing sodium hydroxide into contact with the gas containing carbon dioxide.

[Reference Example 10]
Confirmed that carbon dioxide can be fixed by contacting a mixed solution containing sodium hydroxide and further containing chloride of a group 2 element and chloride of a divalent metal element with a gas containing carbon dioxide. did.

As group 2 element chloride and divalent metal element chloride, magnesium chloride (MgCl ₂ , manufactured by Wako Pure Chemical Industries, Ltd.), zinc chloride (ZnCl ₂ , manufactured by Wako Pure Chemical Industries, Ltd.), strontium chloride (manufactured by Wako Pure Chemical Industries, Ltd.) SrCl ₂ , manufactured by Wako Pure Chemical Industries, Ltd.) and barium chloride (BaCl ₂ , manufactured by Wako Pure Chemical Industries, Ltd.) were used. Each of the chlorides was diluted with distilled water to prepare 0.1 mol / L metal chloride solutions. Further, in the same manner as in Reference Example 5, a 0.1 N sodium hydroxide solution was prepared.

2 mL of each metal chloride solution and 1 mL of the sodium hydroxide solution were mixed. The mixed solution was brought into contact with the mixed solution by bubbling carbon dioxide in the same manner as in Reference Example 5. After the mixing and after the contact with the carbon dioxide, the amount of precipitation was calculated in the same manner as in Reference Example 5.

The result is shown in FIG. FIG. 44 is a graph showing the weight of the precipitate formed in the mixed solution due to the contact with the carbon dioxide. In FIG. 44, the vertical axis shows the weight (g) of the precipitate per test tube, the horizontal axis shows each metal chloride contained in the mixed solution, and the graph on the left shows after the mixing. The graph on the right shows after contact with the carbon dioxide. The value of the weight of the precipitate was taken as the average value of the measured values of a total of 4 samples for each sample of the mixed solution. As shown in FIG. 44, when the magnesium chloride solution and the zinc chloride solution were used, the amount of precipitation increased significantly after the mixing, and the amount of precipitation decreased after contact with the carbon dioxide. When the strontium chloride solution and the barium chloride solution were used, the amount of precipitation increased after the mixing, and the amount of precipitation further increased after contact with the carbon dioxide.

Next, the carbon dioxide concentration after the contact was measured using the chloride of the Group 2 element and the chloride of the divalent metal element.

As the container, the pipe described in Reference Example 8 was used. 50 ml of 0.1 N sodium hydroxide solution and 50 ml of each metal chloride solution of 0.1 mol / L are placed in the pipe, and air is bubbled into the mixed solution in the same manner as in Reference Example 8. Was brought into contact with. After the contact, the carbon dioxide concentration of the gas in the upper space (height of about 14 cm) of the pipe was measured in the same manner as in Reference Example 6. In the measurement, it was confirmed that the value of the carbon dioxide concentration became almost constant 2 to 3 minutes after the contact, and this value was used as the measured value. Moreover, as a control, the carbon dioxide concentration of the air was measured in the same manner.

The result is shown in FIG. FIG. 45 is a graph showing the carbon dioxide concentration in the pipe after the contact. In FIG. 45, the vertical axis represents carbon dioxide concentration (PPM), and the horizontal axis represents each metal chloride. The carbon dioxide concentration value was taken as the average value of the measured values of a total of 3 samples. As shown in FIG. 45, the contact reduced the carbon dioxide concentration in the pipe as compared with the control value, regardless of which metal chloride was used. In particular, when the strontium chloride solution and the barium chloride solution were used, the carbon dioxide concentration was greatly reduced.

As described above, carbon dioxide is produced by contacting a mixed solution containing sodium hydroxide, a chloride of a Group 2 element, and a chloride of a divalent metal element with a gas containing carbon dioxide. I was able to confirm that it can be fixed.

[Reference Example 11]
It was confirmed that carbon dioxide can be fixed by contacting a mixture containing sodium hydroxide and calcium chloride with a gas containing carbon dioxide under predetermined temperature conditions.

In the same manner as in Reference Example 6, a mixed solution containing 0.05 N of the sodium hydroxide and 0.05 mol / L of the calcium chloride was prepared. In a 10 mL test tube, 3 mL of the sodium hydroxide solution of each concentration and 3 mL of the calcium chloride solution of 0.1 mol / L were put and mixed, and carbon dioxide was added to the mixed solution in the same manner as in Reference Example 5. The carbons were brought into contact by bubbling. The bubbling was performed for 10 seconds under the condition of ^{2 cm 3 / sec.} In the contact, the temperature of the mixed solution was adjusted to 5 ° C, 20 ° C, 30 ° C, 40 ° C, 50 ° C and 60 using Unithermo Shaker NTS-120, EYLEA, (Tokyo Rikakikai Co., Ltd.), respectively. The temperature was maintained at ° C., 70 ° C. and 80 ° C. After the contact, the amount of precipitation was calculated in the same manner as in Reference Example 5.

The result is shown in FIG. FIG. 46 is a graph showing the weight of the precipitate formed in the mixed solution due to the contact with the carbon dioxide. In FIG. 46, the vertical axis represents the weight (g) of the precipitate per test tube, and the horizontal axis represents the temperature. As for the value of the weight of the precipitate, the experiment was carried out 3 to 5 times for each of the temperatures, and the measured values of 4 to 8 samples were obtained in each experiment and used as the average value of these measured values. As shown in FIG. 46, a precipitate was formed after contact with the carbon dioxide under any temperature condition. The amount of precipitation was a substantially constant value when the temperature of the mixed solution was between 5 ° C. and 60 ° C., and increased significantly at 70 ° C. Even when the temperature of the mixed solution was 80 ° C., a value larger than the constant value between 5 ° C. and 60 ° C. was obtained.

As described above, it was confirmed that carbon dioxide can be fixed by bringing the mixture containing sodium hydroxide and calcium chloride into contact with the gas containing carbon dioxide under predetermined temperature conditions. In particular, it was confirmed that the fixation of carbon dioxide is suitable for treatment at high temperature.

[Reference Example 12]
It was confirmed that carbon dioxide can be fixed by using the carbon dioxide fixing device of the present invention.

The carbon dioxide fixing device shown in FIG. 47 was produced as follows. As the first reaction vessel 10, a plastic vessel having a size (height 73 cm, depth 41 cm, width 51 cm) and a capacity of about 76 L was used. The first reaction vessel 10 was installed in a metal rack (commercially available). A hose (commercially available) and a pipe (commercially available) were used as the liquid circulation flow path 30, and the hose and the pipe were connected to the pump 40 (Iwaki Magnet Pump MD-100R-5M), respectively. The pump 40 was installed in the space above the rack (accommodation section 50). A strainer (commercially available) is connected to the liquid suction end 310 of the pipe, and an aspirator (part number 1-689-04, manufactured by AS ONE Corporation) is connected to the liquid discharge end 320 of the hose. , Installed in the first reaction vessel 10. Further, a hose X for taking in gas was connected to the aspirator, and the other end of the hose X was passed to the outside through a hole provided in the ceiling of the rack. As a result, the atmosphere taken in from the outside is taken into the liquid in the liquid circulation flow path 30 by the aspirator and ejected from the liquid discharge end 320.

Further, a hole (diameter 6 cm) (not shown) is provided on the side surface of the upper space of the first reaction vessel 10 so as to be at a position 7 cm from the liquid surface, and a vinyl chloride pipe is passed through the hole. The gas in the upper space was released to the outside of the first reaction vessel 10. Then, the carbon dioxide concentration in the released gas was measured by a carbon dioxide monitor (GX-6000, manufactured by RIKEN KEIKI).

After putting 40 L of water into the first reaction vessel 10, 2 L of 1N sodium hydroxide solution was put into the first reaction vessel 10 by an operator. Immediately after the charging, the pump 40 was operated, and the solution was sucked from the liquid suction end 310 by the pump 40, and the sucked solution was discharged from the liquid discharge end 320. Immediately thereafter, a 2 L solution containing 1 mol / L calcium chloride was added by the operator. After the charging, the lid of the first reaction vessel 10 was closed to prevent the ingress and egress of gas. The elapsed time was measured with the time point at which the solution containing calcium chloride was added as 0 minute.

As a result, the carbon dioxide concentration was 400 PPM at the time of charging (0 minutes). Immediately after the addition, the carbon dioxide concentration drops sharply, the carbon dioxide concentration 20 seconds after the addition is 280PPM, the carbon dioxide concentration 30 seconds later is 260PPM, and the carbon dioxide concentration 40 seconds later. Is 220 PPM, the carbon dioxide concentration after 50 seconds is 200 PPM, the carbon dioxide concentration after 60 seconds is 180 PPM, the carbon dioxide concentration after 1 minute 20 seconds is 160 PPM, and the carbon dioxide concentration after 1 minute 40 seconds is 140 PPM. The carbon dioxide concentration after 2 minutes is 100 PPM, the carbon dioxide concentration after 2 minutes and 20 seconds is 80 PPM, the carbon dioxide concentration after 2 minutes and 40 seconds is 60 PPM, and the carbon dioxide concentration after 3 minutes is 40 PPM, 3 The carbon dioxide concentration after 20 minutes was 20 PPM. Then, 3 minutes and 45 seconds after the charging, the carbon dioxide concentration became 0PPM. Then, when the measurement was carried out from the addition to 10 minutes after the addition, the carbon dioxide concentration was 0 PPM at any elapsed time.

As described above, it was confirmed that carbon dioxide can be fixed by using the carbon dioxide fixing device of the present invention.

Although the present invention has been described above with reference to the embodiments and examples, the present invention is not limited to the above embodiments and examples. Various changes that can be understood by those skilled in the art can be made to the structure and details of the present invention within the scope of the present invention.

As described above, according to the present invention, it is possible to provide a new method for fixing carbon dioxide. Therefore, it can be said that the present invention is extremely useful in the treatment of combustion exhaust gas containing carbon dioxide. Further, the present invention can be suitably applied to, for example, a thermal power plant.

1, 2, 3 Carbon dioxide fixing device 10 Reaction vessel 10A 1st reaction vessel 10B 2nd reaction vessel 11 Reaction chamber 11A 1st reaction chamber 11B 2nd reaction chamber 12 Electrolytic chamber 12A Electronodic chamber 12B Cathode chamber 12C Intermediate chamber 121A Anode 121B Cathode 13A, B Partition 20A, B, C Carbon dioxide fixative charging means 30 Gas feeding means 31 Inserting end 40A, B, C Gas taking out 50 Liquid taking out 51 Filter 52 Liquid discharging 53 Pump 54 Flow adjustment means 60 Liquid circulation flow path 61 Liquid suction end 62 Liquid discharge end 63 Aspirator 64 Flow adjustment means 70 Pumps 80, 80A, B Container communication flow paths 81, 81A, B Pumps 82, 82A, B Flow adjustment means 83 Aspirator

Claims (19)

Including contact process and electrolysis process
In the contact step, a mixed solution containing sodium hydroxide and further containing at least one of a chloride of a Group 2 element and a chloride of a divalent metal element is brought into contact with a gas containing carbon dioxide.
The concentration of the sodium hydroxide in the mixed solution is 0.2 N or less, and the concentration is 0.2 N or less.
In the electrolysis step, the mixed solution after the contact is electrolyzed to obtain a mixed solution after electrolysis.
In the contacting step, the mixed solution after electrolysis is reused as the mixed solution, and the mixture is reused.
In the contacting step, the mixed solution and the mixed solution are brought into at least one state selected from the group consisting of standing, flowing, shaking, showering, and atomizing. Contact with gas,
How to fix carbon dioxide. Including contact process and electrolysis process
In the contact step, a mixed solution containing sodium hydroxide and further containing at least one of a chloride of a Group 2 element and a chloride of a divalent metal element is brought into contact with a gas containing carbon dioxide.
The concentration of the sodium hydroxide in the mixed solution is 0.2 N or less, and the concentration is 0.2 N or less.
In the electrolysis step, the mixed solution after the contact is electrolyzed to obtain a mixed solution after electrolysis.
In the contacting step, the mixed solution after electrolysis is reused as the mixed solution, and the mixture is reused.
In the contact step, the mixed solution and the gas are brought into contact with each other in a state where the gas is recirculated.
How to fix carbon dioxide. Including contact process and electrolysis process
In the contact step, a mixed solution containing sodium hydroxide and further containing at least one of a chloride of a Group 2 element and a chloride of a divalent metal element is brought into contact with a gas containing carbon dioxide.
The concentration of the sodium hydroxide in the mixed solution is 0.2 N or less, and the concentration is 0.2 N or less.
In the electrolysis step, the mixed solution after the contact is electrolyzed to obtain a mixed solution after electrolysis.
In the contacting step, the mixed solution after electrolysis is reused as the mixed solution, and the mixture is reused.
In the contact step, the mixed liquid is sucked from the liquid suction end portion of the liquid circulation flow path, and the sucked mixed liquid is discharged from the liquid discharge end portion of the liquid circulation flow path to obtain the mixed liquid. Contact with the gas,
How to fix carbon dioxide. The fixation of carbon dioxide according to claim 3, wherein the liquid circulation flow path includes a gas-liquid mixing member, and the gas can be mixed with the mixed liquid flowing through the liquid circulation flow path by the gas-liquid mixing member. Method. Including contacting process, cooling process, and electrolysis process
In the contact step, a mixed solution containing sodium hydroxide and further containing at least one of a chloride of a Group 2 element and a chloride of a divalent metal element is brought into contact with a gas containing carbon dioxide.
The concentration of the sodium hydroxide in the mixed solution is 0.2 N or less, and the concentration is 0.2 N or less.
In the cooling step, the mixed solution after the contact step is cooled, and the mixture is cooled.
In the electrolysis step, the mixed solution after the contact is electrolyzed to obtain a mixed solution after electrolysis.
In the contacting step, the mixed solution after electrolysis is reused as the mixed solution.
How to fix carbon dioxide. Including contact step, product recovery step, and electrolysis step
In the contact step, a mixed solution containing sodium hydroxide and further containing at least one of a chloride of a Group 2 element and a chloride of a divalent metal element is brought into contact with a gas containing carbon dioxide.
The concentration of the sodium hydroxide in the mixed solution is 0.2 N or less, and the concentration is 0.2 N or less.
In the product recovery step, after the contact step, the reaction product in the mixed solution is recovered, and the reaction product is recovered.
In the electrolysis step, the mixed solution after the contact is electrolyzed to obtain a mixed solution after electrolysis.
In the contacting step, the mixed solution after electrolysis is reused as the mixed solution.
How to fix carbon dioxide. The product recovery step includes a mixing step and a separation step.
In the mixing step, the fixed reaction product is mixed in the mixed solution.
The method for fixing carbon dioxide according to claim 6, wherein the separation step separates the mixed reaction products. Including contact process, electrolysis process, and judgment process
In the contact step, a mixed solution containing sodium hydroxide and further containing at least one of a chloride of a Group 2 element and a chloride of a divalent metal element is brought into contact with a gas containing carbon dioxide.
The concentration of the sodium hydroxide in the mixed solution is 0.2 N or less, and the concentration is 0.2 N or less.
In the electrolysis step, the mixed solution after the contact is electrolyzed to obtain a mixed solution after electrolysis.
In the contacting step, the mixed solution after electrolysis is reused as the mixed solution, and the mixture is reused.
In the determination step, a computer determines whether or not to proceed from a predetermined step to the next step.
At least one of the predetermined step and the next step is a step including at least one of the contact step and the electrolysis step.
How to fix carbon dioxide. Including a first contact step, a dilution step, a second contact step, and an electrolysis step,
In the first contact step, a solution containing sodium hydroxide and a gas containing carbon dioxide are brought into contact with each other.
In the dilution step, after the first contact step, the concentration of sodium hydroxide in the solution is diluted to 0.2 N or less.
In the second contact step, after the first contact step, at least one of a chloride of a Group 2 element and a chloride of a divalent metal element is added to the solution.
In the electrolysis step, after the second contact step, a mixed solution of the solution containing sodium hydroxide and at least one of the chloride of the group 2 element and the chloride of the divalent metal element is electrolyzed. death,
In the first contact step, the mixed solution after electrolysis is reused as a solution containing the sodium hydroxide.
In the first contact step, the solution is brought into at least one state selected from the group consisting of standing, flowing, shaking, showering, and atomizing with the solution. Contact with the gas,
How to fix carbon dioxide. Including a first contact step, a dilution step, a second contact step, and an electrolysis step,
In the first contact step, a solution containing sodium hydroxide and a gas containing carbon dioxide are brought into contact with each other.
In the dilution step, after the first contact step, the concentration of sodium hydroxide in the solution is diluted to 0.2 N or less.
In the second contact step, after the first contact step, at least one of a chloride of a Group 2 element and a chloride of a divalent metal element is added to the solution.
In the electrolysis step, after the second contact step, a mixed solution of the solution containing sodium hydroxide and at least one of the chloride of the group 2 element and the chloride of the divalent metal element is electrolyzed. death,
In the first contact step, the mixed solution after electrolysis is reused as a solution containing the sodium hydroxide.
In the first contact step, the solution and the gas are brought into contact with each other in a state where the gas is recirculated.
How to fix carbon dioxide. Including a first contact step, a dilution step, a second contact step, and an electrolysis step,
In the first contact step, a solution containing sodium hydroxide and a gas containing carbon dioxide are brought into contact with each other.
In the dilution step, after the first contact step, the concentration of sodium hydroxide in the solution is diluted to 0.2 N or less.
In the second contact step, after the first contact step, at least one of a chloride of a Group 2 element and a chloride of a divalent metal element is added to the solution.
In the electrolysis step, after the second contact step, a mixed solution of the solution containing sodium hydroxide and at least one of the chloride of the group 2 element and the chloride of the divalent metal element is electrolyzed. death,
In the first contact step, the mixed solution after electrolysis is reused as a solution containing the sodium hydroxide.
In the first contact step, the solution is sucked from the liquid suction end of the liquid circulation flow path, and the sucked solution is discharged from the liquid discharge end of the liquid circulation flow path to obtain the solution. Contact with the gas,
How to fix carbon dioxide. The method for fixing carbon dioxide according to claim 11, wherein the liquid circulation flow path includes a gas-liquid mixing member, and the gas can be mixed with the solution flowing through the liquid circulation flow path by the gas-liquid mixing member. .. Including a first contact step, a dilution step, a second contact step, a cooling step, and an electrolysis step.
In the first contact step, a solution containing sodium hydroxide and a gas containing carbon dioxide are brought into contact with each other.
In the dilution step, after the first contact step, the concentration of sodium hydroxide in the solution is diluted to 0.2 N or less.
In the second contact step, after the first contact step, at least one of a chloride of a Group 2 element and a chloride of a divalent metal element is added to the solution.
The cooling step includes the solution after the first contact step, the solution containing the sodium hydroxide after the second contact step, the chloride of the Group 2 element, and the divalent metal element. Cool at least one of the mixture with at least one of the chlorides,
The electrolysis step, after the second contacting step, electrolysis of the mixture,
In the first contact step, the mixed solution after electrolysis is reused as a solution containing the sodium hydroxide.
How to fix carbon dioxide. Including a first contact step, a dilution step, a second contact step, a product recovery step, and an electrolysis step.
In the first contact step, a solution containing sodium hydroxide and a gas containing carbon dioxide are brought into contact with each other.
In the dilution step, after the first contact step, the concentration of sodium hydroxide in the solution is diluted to 0.2 N or less.
In the second contact step, after the first contact step, at least one of a chloride of a Group 2 element and a chloride of a divalent metal element is added to the solution.
In the product recovery step, after the second contact step, the solution containing the sodium hydroxide and at least one of the chloride of the Group 2 element and the chloride of the divalent metal element are contained in a mixed solution. Collect the reaction product and
The electrolysis step, after the second contacting step, electrolysis of the mixture,
In the first contact step, the mixed solution after electrolysis is reused as a solution containing the sodium hydroxide.
How to fix carbon dioxide. The product recovery step includes a mixing step and a separation step.
In the mixing step, the fixed reaction product is mixed in the mixed solution.
The method for fixing carbon dioxide according to claim 14, wherein the separation step separates the mixed reaction products. Including a first contact step, a dilution step, a second contact step, an electrolysis step, and a determination step.
In the first contact step, a solution containing sodium hydroxide and a gas containing carbon dioxide are brought into contact with each other.
In the dilution step, after the first contact step, the concentration of sodium hydroxide in the solution is diluted to 0.2 N or less.
In the second contact step, after the first contact step, at least one of a chloride of a Group 2 element and a chloride of a divalent metal element is added to the solution.
In the electrolysis step, after the second contact step, a mixed solution of the solution containing sodium hydroxide and at least one of the chloride of the group 2 element and the chloride of the divalent metal element is electrolyzed. death,
In the first contact step, the mixed solution after electrolysis is reused as a solution containing the sodium hydroxide.
In the determination step, a computer determines whether or not to proceed from a predetermined step to the next step.
At least one of the predetermined step and the next step comprises at least one selected from the group consisting of the first contact step, the dilution step, the second contact step, and the electrolysis step. It's a process,
How to fix carbon dioxide. Includes an immobilization step to immobilize carbon dioxide
A method for producing immobilized carbon dioxide, wherein the immobilization step is carried out by the method for immobilizing carbon dioxide according to any one of claims 1 to 16. Includes reaction vessel, carbon dioxide fixative charging means, gas-liquid mixing means, and gas extraction section
The carbon dioxide fixative charging means can charge the carbon dioxide fixative into the reaction vessel.
The reaction vessel includes a reaction chamber and an electrolysis chamber.
The reaction chamber can contain a carbon dioxide fixative and
The gas-liquid mixing means can mix a gas containing carbon dioxide with the carbon dioxide fixative contained in the reaction chamber, and is inserted into the reaction chamber, and the insertion end portion is a water repellent. And coated with at least one of the electrically negative materials,
The electrolysis chamber includes an anode chamber and a cathode chamber.
Liquids can be sent from the reaction chamber to the electrolysis chamber and from the electrolysis chamber to the reaction chamber, respectively.
In the reaction chamber, the carbon dioxide fixative and carbon dioxide are reacted to each other.
The carbon dioxide fixative after the reaction can be sent from the reaction chamber to the electrolysis chamber.
In the electrolytic chamber, the carbon dioxide fixative after the reaction is electrolyzed and
The carbon dioxide fixative after electrolysis can be sent from the electrolytic chamber to the reaction chamber.
The gas extraction unit includes a first gas extraction unit and a second gas extraction unit.
The first gas extraction unit can extract gas from the anode chamber, and can extract gas from the anode chamber.
The second gas take-out unit can take out gas from the cathode chamber, and can take out gas from the cathode chamber.
In the reaction chamber, the carbon dioxide fixative after electrolysis can be reused as the carbon dioxide fixative.
Carbon dioxide fixation device. Includes reaction vessel, carbon dioxide fixative charging means, gas-liquid mixing means, and liquid extraction section.
The carbon dioxide fixative charging means can charge the carbon dioxide fixative into the reaction vessel.
The reaction vessel includes a reaction chamber and an electrolysis chamber.
The reaction chamber can contain a carbon dioxide fixative and
The gas-liquid mixing means can mix a gas containing carbon dioxide with the carbon dioxide fixative contained in the reaction chamber, and is inserted into the reaction chamber, and the insertion end portion is a water repellent. And coated with at least one of the electrically negative materials,
The electrolysis chamber includes an anode chamber and a cathode chamber.
Liquids can be sent from the reaction chamber to the electrolysis chamber and from the electrolysis chamber to the reaction chamber, respectively.
In the reaction chamber, the carbon dioxide fixative and carbon dioxide are reacted to each other.
The carbon dioxide fixative after the reaction can be sent from the reaction chamber to the electrolysis chamber.
In the electrolytic chamber, the carbon dioxide fixative after the reaction is electrolyzed and
The carbon dioxide fixative after electrolysis can be sent from the electrolytic chamber to the reaction chamber.
The liquid take-out unit can take out the carbon dioxide fixative from the reaction vessel.
In the reaction chamber, the carbon dioxide fixative after electrolysis can be reused as the carbon dioxide fixative.
Carbon dioxide fixation device.

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