Acidic gas separation device, air purifier, air conditioner, and acidic gas concentrator

Abstract

One aspect of the present invention provides an acidic gas separation device which is provided with an electrolyte layer, a pair of electrodes that are arranged so as to have the electrolyte layer sandwiched therebetween, and a voltage application unit that applies a voltage between the pair of electrodes, wherein: the pair of electrodes are gas permeable electrodes; and the electrolyte layer contains a nonvolatile electrolyte solution and at least one compound that is selected from the group consisting of high molecular weight redox compounds having a radicalization rate of 90% or more, high molecular weight redox compounds having a quinone group in each molecule, and high molecular weight redox compounds having an imino group in each molecule.

Description

Technical Field

[0001] The present invention relates to an acidic gas separation device, an air purifier, an air conditioner, and an acidic gas concentrator.

Background Art

[0002] Carbon dioxide, known as an acidic gas, not only widely exists on the earth, accounting for about 0.04% of the atmosphere, but is also widely used industrially. Examples of the uses of carbon dioxide include, for example, a foaming gas for carbonated beverages, bath salts, and fire extinguishers, dry ice used for cooling, etc., and air for emergency replenishment of bicycle tires. Further, carbon dioxide can also be used as an extraction solvent for extracting caffeine and the like by bringing it into a supercritical state. Carbon dioxide is also used in carbon dioxide lasers used in lasers for processing in the industrial field and medical laser scalpels. Furthermore, carbon dioxide may be used as a refrigerant for a compressor instead of a chlorofluorocarbon refrigerant. In the agricultural field as well, carbon dioxide is used, for example, for carbon dioxide fertilization to accelerate the growth of plants such as strawberries in forced cultivation and aquatic plants in ornamental aquariums. Carbon dioxide is also used for CA (Controlled Atmosphere) storage of fresh agricultural products.

[0003] As described above, since carbon dioxide is used in various fields, a method for obtaining carbon dioxide by separating carbon dioxide from a gas containing carbon dioxide such as air is required. In addition, carbon dioxide is also said to be a causative substance of global warming. From this as well, it is required to separate carbon dioxide from a gas containing carbon dioxide and utilize carbon dioxide.

[0004] Furthermore, the activity state of humans varies greatly depending on the carbon dioxide concentration indoors. Generally, it is said that when the carbon dioxide concentration exceeds 1000 ppm, attention decreases. From this, it is required to reduce the carbon dioxide concentration in closed spaces such as automobiles and in living rooms, etc. However, for reasons such as avoiding changes in indoor temperature and odors, it is often difficult in real life to reduce the carbon dioxide concentration by performing ventilation regularly. From this perspective as well, there is a need for a technology to reduce the indoor carbon dioxide concentration by separating carbon dioxide from a gas containing carbon dioxide and preferentially exhausting the separated carbon dioxide.

[0005] As methods for separating carbon dioxide from a mixed gas containing oxygen and carbon dioxide such as air, various methods have been proposed. Examples of such separation methods include a method of adsorbing carbon dioxide in the air using an adsorbent for carbon dioxide and then desorbing the carbon dioxide adsorbed on the absorbent to separate carbon dioxide from the air. Examples of adsorbents for adsorbing carbon dioxide include activated carbon, amine-based solvents, and aqueous potassium carbonate solutions. Further, as a method for separating carbon dioxide using an adsorbent, more specifically, a pressure swing adsorption (PSA) method in which carbon dioxide is adsorbed on an adsorbent under high pressure and then the pressure is reduced to desorb carbon dioxide from the adsorbent can be mentioned. Examples of adsorbents used when separating carbon dioxide by this PSA method include the adsorbents described in Patent Document 1.

[0006] Patent Document 1 describes an adsorbent for carbon dioxide composed of a composition in which 2 to 80 equivalent% of sodium ions of sodium-containing aluminosilicate are ion-exchanged with barium ions.

[0007] In addition, it is also required to separate not only carbon dioxide but also other acidic gases such as NOx, SOx, and hydrogen sulfide from a gas containing acidic gases. Examples of devices for adsorbing and separating acidic gases such as carbon dioxide include the devices described in Patent Document 2 and Patent Document 3.

[0008] Patent Document 2 describes an acid gas adsorption / desorption device having an acid gas adsorption / desorption layer containing a compound capable of adsorbing and desorbing an acid gas and a substrate by performing oxidation and reduction, and a pair of electrodes sandwiching the acid gas adsorption / desorption layer.

[0009] Patent Document 3 describes a carbon dioxide separation device including an electrolyte layer, a pair of electrodes provided on the electrolyte layer with the electrolyte layer therebetween, and a voltage application unit for applying a voltage between the pair of electrodes, wherein the pair of electrodes are each an electrode permeable to gas, and the electrolyte layer contains an electrolytic solution capable of dissolving carbon dioxide and a redox compound having an N-oxyradical group in the molecule.

[0010] According to Patent Document 1, it is disclosed that an adsorbent can be provided which has a high selectivity ratio for carbon dioxide and a large absorption capacity even under conditions with a large amount of moisture. Further, it is disclosed that this adsorbent can be suitably used for separating and concentrating carbon dioxide by the PSA method.

[0011] In a method for separating carbon dioxide by such a PSA method, for example, in the method using the adsorbent described in Patent Document 1, as described above, pressurization and depressurization are required. Further, in any method for separating carbon dioxide using an adsorbent, not only an operation of adsorbing carbon dioxide to the adsorbent but also an operation of desorbing the carbon dioxide adsorbed to the adsorbent, for example, heat treatment or the like is required. For this reason, the method for separating carbon dioxide using an adsorbent may require a relatively large amount of energy or a relatively large-sized apparatus.

[0012] According to Patent Document 2, it is disclosed that acid gas can be separated and desorbed in a solid state. Specifically, in the apparatus described in Patent Document 2, first, a voltage is applied between the electrodes to adsorb the acid gas on the acid gas adsorption / desorption layer. Then, the voltage applied between the electrodes is reversed so that the current flowing through the acid gas adsorption / desorption layer disposed between the electrodes is in the opposite direction to that during adsorption, and the acid gas is desorbed from the acid gas adsorption / desorption layer. Thus, in the apparatus described in Patent Document 2, it is necessary to reverse the voltage applied between the electrodes when adsorbing the acid gas on the acid gas adsorption / desorption layer and when desorbing the adsorbed acid gas from the acid gas adsorption / desorption layer. Even when attempting to separate the acid gas with the apparatus described in this Patent Document 2, as described above, it was necessary to reverse the voltage applied between the electrodes. Therefore, with the apparatus described in Patent Document 2, the acid gas could not be continuously separated from the gas containing the acid gas. Thus, with the apparatus described in Patent Document 2, similar to the case of using the adsorbent described in Patent Document 1, relatively large amounts of energy may be required, or relatively large-sized apparatuses may be required in some cases.

[0013] On the other hand, according to Patent Document 3, it is disclosed that carbon dioxide can be separated without reversing the voltage applied between a pair of electrodes just by applying a voltage between the electrodes, so that carbon dioxide can be easily separated from the gas containing carbon dioxide. Therefore, by using the apparatus described in Patent Document 3, since it is not necessary to reverse the voltage applied between the electrodes, carbon dioxide can be continuously separated from the gas containing carbon dioxide. Also, carbon dioxide can be easily separated from the gas containing carbon dioxide with a small-sized apparatus.

[0014] As an apparatus capable of separating acid gases such as carbon dioxide, it is required to more efficiently separate the acid gas from the gas containing the acid gas, and at the same time, to be able to repeatedly separate the acid gas from the gas containing acid gases such as carbon dioxide over a long period of time.

Prior Art Documents

Patent Documents

[0015]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

[0016] The present invention has been made in view of such circumstances, and an object thereof is to provide an acidic gas separation device that can easily separate acidic gas from a gas containing acidic gas and can repeat this separation over a long period. Another object of the present invention is to provide an air cleaner, an air conditioner, and an acidic gas concentrator provided with the acidic gas separation device.

[0017] One aspect of the present invention includes an electrolyte layer, a pair of electrodes provided with the electrolyte layer interposed therebetween, and a voltage application unit that applies a voltage between the pair of electrodes. Each of the pair of electrodes is an electrode through which gas can permeate. The electrolyte layer contains at least one selected from the group consisting of a high molecular weight redox compound having a radicalization rate of 90% or more, a high molecular weight redox compound having a quinone group in the molecule, and a high molecular weight redox compound having an imino group in the molecule, and a non-volatile electrolyte solution. It is an acidic gas separation device characterized by that.

[0018] The above and other objects, features, and advantages of the present invention will become apparent from the following detailed description and the accompanying drawings.

Brief Description of the Drawings

[0019]

Figure 1

Figure 2

Figure 3

Embodiments for Carrying Out the Invention

[0020] Hereinafter, embodiments of the present invention will be described, but the present invention is not limited thereto.

[0021] As shown in FIG. 1, an acidic gas separation device 10 according to an embodiment of the present invention includes an electrolyte layer 13, a pair of electrodes 11 and 12 provided with the electrolyte layer 13 interposed therebetween, and a voltage application unit 14 that applies a voltage between the pair of electrodes 11 and 12. The pair of electrodes 11 and 12 are electrodes through which gas can permeate. Further, the electrolyte layer 13 contains at least one selected from the group consisting of a high molecular weight redox compound having a radicalization rate of 90% or more, a high molecular weight redox compound having a quinone group in the molecule, and a high molecular weight redox compound having an imino group in the molecule, and a non-volatile electrolyte solution. Further, from the viewpoint of long-term repetitive durability, it is important that the electrolyte layer 13 contains any of the high molecular weight redox compounds. Each of the high molecular weight redox compounds is a compound in which an acidic gas is adsorbed by electrolytic reduction and the adsorbed acidic gas is desorbed by electrolytic oxidation. Note that FIG. 1 is a schematic cross-sectional view showing the configuration of the acidic gas separation device 10 according to the embodiment of the present invention.

[0022] Note that non-volatile means that the substance does not evaporate or does not evaporate immediately under normal temperature and pressure. Specifically, it means that the mass of the substance is maintained at 99% by mass or more even after being left for 24 hours under normal temperature and pressure. That is, the non-volatile electrolyte solution means an electrolyte solution that does not evaporate or does not evaporate immediately under normal temperature and pressure. Specifically, it means an electrolyte solution that maintains the mass of the substance at 99% by mass or more even after being left for 24 hours under normal temperature and pressure.

[0023] The acid gas separation device 10 according to this embodiment may be applied by the voltage application unit 14 to increase the potential of either electrode between the pair of electrodes 11 and 12. In either case, the acid gas can be separated. Here, the case will be described where the voltage application unit 14 applies a voltage between the electrodes 11 and 12 so that the potential of one electrode 11 becomes lower than the potential of the other electrode 12. In this case, one electrode 11 becomes the electrode (first electrode: cathode electrode) 11 that takes in the acid gas from the gas containing the acid gas, and the other electrode 12 becomes the electrode (second electrode: anode electrode) 12 that releases the acid gas from the electrolyte layer 13.

[0024] The acid gas separation device 10 may include a first flow path 15 through which the gas flows while contacting the first electrode 11, and a second flow path 16 through which the gas flows while contacting the second electrode 12.

[0025] The acid gas separation device 10 according to this embodiment can easily separate acid gas from a gas containing acid gas. Specifically, when a voltage is applied between the first electrode 11 and the second electrode 12 by the voltage application unit 14 such that the potential of the first electrode 11 becomes lower than the potential of the second electrode 12, the acid gas is separated from the gas containing acid gas as follows. When the acid gas separation device 10 allows a gas containing acid gas, such as air, to flow through the first flow path 15 and brings the acid gas into contact with the first electrode 11, the acid gas preferentially permeates the electrolyte layer 13 and is discharged from the second electrode 12 side. Since the acid gas preferentially permeates the electrolyte layer 13 in this way, a gas with a high acid gas concentration flows through the second flow path 16. In this way, the acid gas separation device 10 can preferentially permeate the acid gas simply by applying a voltage between the first electrode 11 and the second electrode 12. Therefore, when the acid gas separation device 10 is used, the acid gas is separated from the gas containing acid gas. In the acid gas separation device 10, when a gas containing acid gas, nitrogen, and oxygen, such as air, is supplied from the supply port 15a of the first flow path 15, the acid gas (mainly carbon dioxide in the case of air) is discharged from the second flow path 16, and a gas with a lower acid gas concentration (e.g., carbon dioxide concentration) than the supplied gas is discharged from the discharge port 15b of the first flow path 15. Along with this, since the acid gas concentration (e.g., carbon dioxide concentration) decreases from the discharge port 15b of the first flow path 15, a gas in which the respective concentrations of nitrogen and oxygen have relatively increased is discharged.

[0026] The above is considered to be due to the following.

[0027] The acidic gas that contacts the first electrode 11 and permeates through the first electrode 11 also contacts the electrolyte layer 13. Specifically, the acidic gas contained in the gas existing around the first electrode 11 permeates through the first electrode 11 and contacts the surface of the electrolyte layer 13 (the surface on the side of the first electrode 11). At this time, due to the voltage applied by the voltage application unit 14, on the side closer to the first electrode 11, the redox compound (high molecular weight redox compound) contained in the electrolyte layer 13 is electrochemically reduced and becomes a reduced form. The acidic gas that contacts the surface of the electrolyte layer 13 (the surface on the side of the first electrode 11) combines with this reduced form and is incorporated into the electrolyte layer 13. Therefore, the uptake of acidic gas to the first electrode 11 side is promoted. On the other hand, due to the voltage applied by the voltage application unit 14, on the side closer to the second electrode 12, the high molecular weight redox compound and the reduced form of the high molecular weight redox compound contained in the electrolyte layer 13 are electrochemically oxidized and become radical forms or oxidized forms. For this reason, when the high molecular weight redox compound to which the acidic gas is bound flows in the electrolyte layer 13 from the side closer to the first electrode 11 to the side closer to the second electrode 12, the acidic gas bound to the high molecular weight redox compound is detached from the high molecular weight redox compound. That is, even if the acidic gas is bound to the reduced form of the high molecular weight redox compound, when the high molecular weight redox compound to which the acidic gas is bound is electrochemically oxidized on the side closer to the second electrode 12, the acidic gas is detached from the high molecular weight redox compound. Therefore, on the side closer to the first electrode 11, the acidic gas is bound to the high molecular weight redox compound, and then, when the high molecular weight redox compound to which the acidic gas is bound flows through the electrolyte layer 13 to the side closer to the second electrode 12, the acidic gas is detached from the high molecular weight redox compound on the side closer to the second electrode 12. Then, the acidic gas detached from the high molecular weight redox compound is released from the surface of the electrolyte layer 13 (the surface on the side of the second electrode 12) and permeates through the second electrode 12. Through the binding and detachment of the acidic gas to the high molecular weight redox compound as described above, it is considered that the acidic gas separation device 10 can take in the acidic gas on the first electrode 11 side and release the acidic gas on the second electrode side.

[0028] When a voltage is applied such that the potential of one electrode 11 becomes higher than the potential of the other electrode 12, one electrode 11 becomes the electrode (second electrode) that releases the acidic gas from the electrolyte layer 13, and the other electrode 12 becomes the electrode (first electrode) that takes in the acidic gas from the gas containing the acidic gas. Therefore, on the side of the other electrode 12, the acidic gas can be taken in, and on the side of one electrode 11, the acidic gas can be released.

[0029] From the above, the acidic gas separation device 10 can continuously separate the acidic gas only by applying a voltage between the pair of electrodes 11 and 12 without inverting the voltage applied between the electrodes (without switching the potential levels of the respective electrodes). That is, in the acidic gas separation device 10, when a voltage is continuously applied between the pair of electrodes 11 and 12 by the voltage application unit 14, the acidic gas can be continuously separated from the gas containing the acidic gas continuously supplied to the first electrode 11 side. Therefore, the acidic gas separation device 10 can easily separate the acidic gas from the gas containing the acidic gas.

[0030] On the other hand, when continuously separating the acidic gas from this gas containing the acidic gas (continuous operation), segregation due to self-aggregation of the redox compound on the surface or inside, which occurs through diffusion or migration of the redox compound constituting the electrolyte layer, may inhibit the separation of the acidic gas. In contrast, in the case of the acidic gas separation device 10, by using a high molecular weight redox compound as the redox compound contained in the electrolyte layer 13, the molecular mobility of the redox compound is suppressed because the entanglement of the molecular chains is promoted, making it difficult to form an aggregated structure. As a result, segregation of the redox compound in the electrolyte layer can be suppressed. For this reason, the acidic gas separation device 10 can repeatedly perform acidic gas separation over a longer period.

[0031] The electrolyte layer 13 is not particularly limited as long as it contains at least one selected from the group consisting of high molecular weight redox compounds having a radicalization rate of 90% or more, high molecular weight redox compounds having a quinone group in the molecule, and high molecular weight redox compounds having an imino group in the molecule, and a non-volatile electrolytic solution. Further, the electrolyte layer 13 is an acidic gas separator that contributes to the separation of acidic gases.

[0032] Here, the high molecular weight redox compound means a redox compound having a repeating unit substantially or conceptually. Specifically, the high molecular weight redox compound includes redox compounds such as polymers produced mainly from monomers or cross-linked products thereof. Examples of the high molecular weight redox compound having a radicalization rate of 90% or more include those among such high molecular weight redox compounds having a radicalization rate of 90% or more. Examples of the high molecular weight redox compound having a quinone group in the molecule include those among the above high molecular weight redox compounds having a quinone group in the molecule, such as high molecular weight redox compounds (polyquinones, etc.) obtained by polymerizing monomers containing a quinone group. Examples of the high molecular weight redox compound having an imino group in the molecule include those among the above high molecular weight redox compounds having an imino group in the molecule, such as high molecular weight redox compounds (polyanilines, etc.) obtained by polymerizing monomers containing an aniline group.

[0033] The high molecular weight redox compound adsorbs and desorbs acidic gases by electrolytic reduction and electrolytic oxidation. That is, when the high molecular weight redox compound is electrolytically reduced, acidic gases are adsorbed to the high molecular weight redox compound, and when the high molecular weight redox compound is electrolytically oxidized, the acidic gases adsorbed to the high molecular weight redox compound are desorbed from the high molecular weight redox compound.

[0034] The weight average molecular weight of the high molecular weight redox compound is not particularly limited. However, the larger the weight average molecular weight of the high molecular weight redox compound, the more likely it is to suppress the segregation of the redox compound inside or on the surface of the membrane in the electrolyte membrane. For this reason, the lower limit of the weight average molecular weight of the high molecular weight redox compound is preferably 1,000 or more, more preferably 2,000 or more, even more preferably 10,000 or more, and particularly preferably 20,000 or more. On the other hand, by reducing the weight average molecular weight of the high molecular weight redox compound, the solubility of the high molecular weight redox compound increases, and a sufficient amount of the high molecular weight redox compound can be contained in the electrolyte membrane. As a result, the separation performance of the acidic gas can be improved. For this reason, the upper limit of the weight average molecular weight of the high molecular weight redox compound is preferably 5,000,000 or less, more preferably 3,000,000 or less, even more preferably 1,000,000 or less, and particularly preferably 500,000 or less. Further, the upper limit of the weight average molecular weight of the high molecular weight redox compound may be 400,000 or less, 300,000 or less, 200,000 or less, 150,000 or less, or 100,000 or less.

[0035] As for the measurement of the weight average molecular weight of the high molecular weight redox compound here, methods such as using gel permeation chromatography (GPC) and converting with standard polymethyl methacrylate can be mentioned.

[0036] As the high molecular weight redox compound with a radicalization rate of 90% or more, it is preferably a compound having an unpaired electron or a polymer having a compound having an unpaired electron as the main component of the monomer by oxidation or reduction. The main component means that the proportion in the monomer is high. For example, it is preferably 80% by mass or more based on the total amount of the monomers.

[0037] As for the high molecular weight redox compound with a radicalization rate of 90% or more, as long as it is a high molecular weight redox compound with a radicalization rate of 90% or more, it is not particularly limited. For example, poly(N-oxyradical) with a radicalization rate of 90% or more and its derivatives can be mentioned. Poly(N-oxyradical) is a high molecular weight redox compound having an N-oxyradical group in the molecule. When this high molecular weight redox compound is brought into a state where the N-oxyradical group is reduced by applying a voltage between the electrodes 11 and 12 by the voltage application unit 14 or the like, the N-oxyradical group becomes an N-oxyanion group. Also, when the N-oxyanion group is oxidized by applying a voltage between the electrodes 11 and 12 or the like, the N-oxyanion group returns to the N-oxyradical base returns.

[0038] As for the high molecular weight redox compound having a quinone group in the molecule, as long as it is a high molecular weight redox compound having a quinone group in the molecule, it is not particularly limited. For example, polyquinone and its derivatives can be mentioned. When this high molecular weight redox compound is brought into a state where the quinone group is reduced by applying a voltage between the electrodes 11 and 12 by the voltage application unit 14 or the like, it becomes a dioxyanion group. Also, when the dioxyanion group is oxidized by applying a voltage between the electrodes 11 and 12 or the like, the dioxyanion group returns to the quinone group.

[0039] The high molecular weight redox compound having an imino group in the molecule is not particularly limited as long as it is a high molecular weight redox compound having an imino group in the molecule. For example, polyaniline and its derivatives can be mentioned. Polyaniline is a linear high molecular weight redox compound in which aniline is bonded at the para position. When this high molecular weight redox compound is brought into a state where the imino group is reduced by applying a voltage between the electrodes 11 and 12 by the voltage application unit 14 or the like, it becomes an aminoanion group. Also, when the aminoanion group is oxidized by applying a voltage between the electrodes 11 and 12 or the like, the aminoanion group returns to the imino group.

[0040] A high molecular weight redox compound is, as described above, a compound in which functional groups such as an imino group, a quinone group, and an N-oxy radical group are electrochemically changed by oxidation-reduction. Specifically, a high molecular weight redox compound having a radicalization rate of 90% or more is a compound having a functional group that can be mutually converted between a radical group and an anion group or a cation group by an oxidation-reduction reaction, and preferably a polymer containing, as its constituent unit, a monomer unit having a functional group whose functional group portion can be mutually converted between a radical group and an anion group or a cation group by an oxidation-reduction reaction. The polymer may be obtained by polymerizing a monomer having a functional group that can be mutually converted between a radical group and an anion group or a cation group by the oxidation-reduction reaction, or a functional group that can be mutually converted between a radical group and an anion group or a cation group by the oxidation-reduction reaction may be introduced by post-modification into a part or all of the monomer units of the polymer. Further, the high molecular weight redox compound may be crosslinked.

[0041] The amount of the monomer unit having a functional group that can be mutually converted between a radical group and an anion group or a cation group by an oxidation-reduction reaction is preferably 80 mol% or more, more preferably 90 mol% or more, and even more preferably 95 mol% or more with respect to all the monomer units constituting the polymer (a polymer containing, as its constituent unit, a monomer unit having a functional group that can be mutually converted between a radical group and an anion group or a cation group by an oxidation-reduction reaction). Being within the above range is suitable in terms of retention of acidic substances and transfer efficiency.

[0042] As monomer units constituting a high molecular weight redox compound having a radicalization rate of 90% or more, for example, 4-acryloyloxy-2,2,6,6-tetramethylpiperidinyl oxy radical, 4-methacryloyloxy-2,2,6,6-tetramethylpiperidinyl oxy radical, 3-acryloyloxy-2,2,6,6-tetramethylpyrrolidinyl oxy radical, 3-methacryloyloxy-2,2,6,6-tetramethylpyrrolidinyl oxy radical, 4-vinylroyloxy-2,2,6,6-tetramethylpiperidylnyl oxy radical, and 4-vinylroyloxy-2,2,5,5-tetramethylpyrrolidinyl oxy radical, etc. Monomer units in the case of polymerizing at least one selected from the group as a monomer can be mentioned. That is, examples of the high molecular weight redox compound having a radicalization rate of 90% or more include polymers obtained by polymerizing these compounds as monomers.

[0043] As monomer units constituting a high molecular weight redox compound having a quinone group in the molecule, for example, 2-vinyl-1,4-benzoquinone, 2-vinyl-1,4-naphthoquinone, 2,5-diacryloyloxymethyl-1,4-benzoquinone, 2,6-diacryloyloxymethyl-1,4-naphthoquinone, 1,4-diacryloyloxymethylanthraquinone, 1,4-diacryloyloxyethylnaphthoquinone, 1,4-dichloroanthraquinone, 1,4-dibromoanthraquinone, 1,4-dichloronaphthoquinone, 1,4-dibromonaphthoquinone, 2,5-dichlorobenzoquinone, and 2,5-dibromobenzoquinone, etc. Monomer units in the case of polymerizing at least one selected from the group as a monomer can be mentioned. That is, examples of the high molecular weight redox compound having a quinone group in the molecule include polymers obtained by polymerizing these compounds as monomers.

[0044] As monomer units constituting a high molecular weight redox compound having an imino group in the molecule, for example, aniline, 1,4-diaminonaphthalene, 2-methyl-aniline, 2,3-dimethylaniline andExamples of the monomer unit include those obtained by polymerizing at least one selected from 9,10-diaminoanthracene and the like as a monomer. That is, examples of the high molecular weight redox compound having an imino group in the molecule include polymers obtained by polymerizing these compounds as monomers.

[0045] The high molecular compound may contain only one kind of the monomer unit or two or more kinds thereof. That is, the high molecular compound may be a polymer obtained by polymerizing a monomer alone, or may be a polymer obtained by polymerizing a combination of two or more monomers. Further, the high molecular weight redox compound may be a compound obtained by polymerizing only the above-exemplified monomers, or may be a copolymer obtained by copolymerizing the above-exemplified monomers and a copolymerization monomer such as ethylene, propylene, butadiene, isoprene, styrene, and vinyl acetate. Also, this copolymerization monomer may be used alone or in combination of two or more.

[0046] Among the above-exemplified compounds, the high molecular weight redox compound is preferably a high molecular weight redox compound having a radicalization rate of 90% or more from the viewpoint of electrochemical stability, and more preferably a compound containing a repeating unit represented by the following formula (1). The compound containing the repeating unit represented by the following formula (1) may contain a single repeating unit or may be used in combination of two or more.

[0047]

Chemical formula

[0048] Further, the compound containing the repeating unit represented by the formula (1) may be a compound obtained by synthesis using a predetermined synthesis method, or may be a commercially available product. The synthesis method is not particularly limited as long as it is a synthesis method for obtaining a compound containing the repeating unit represented by the formula (1). For example, a method of nitroxidation for oxidizing the amino group of a disubstituted amine compound can be mentioned.

[0049] The radicalization rate of a high molecular weight redox compound having a radicalization rate of 90% or more is not particularly limited as long as it is 90% or more. For example, it is preferably 90 to 99% by mass, more preferably 95 to 99% by mass, and even more preferably 97 to 99% by mass. If the radicalization rate is too low, the reactivity with acidic gases such as carbon dioxide decreases, and the transport efficiency tends to decrease. The radicalization rate is the ratio of the monomer unit that has become a radical group to all monomer units (all monomer units having a functional group that can be mutually converted between a radical group and an anion group or a cation group by a redox reaction) in the case of a polymer containing a monomer unit having a functional group that can be mutually converted between a radical group and an anion group or a cation group by a redox reaction as its constituent unit. In the case of the compound containing the repeating unit represented by the formula (1), the radicalization rate is the content rate of the repeating unit represented by the formula (1) with respect to all monomer units.

[0050] Here, as a method for measuring the radicalization rate (content rate of the repeating unit represented by the formula (1)), for example, a method for quantifying a nitroxide free radical using a chemical titration method (redox titration method) based on a redox reaction, a method for calculating by quantifying the spin concentration in the reaction product using electron spin resonance (ESR method), etc. can be mentioned.

[0051] The electrolyte layer 13 contains a non-volatile electrolyte solution. The electrolyte solution is preferably a compound that is electrochemically stable and has a wide potential window. Further, the electrolyte solution is non-volatile and is not particularly limited as long as it can be used as an electrolyte solution. As the electrolyte solution, an ionic liquid is preferably used. When an ionic liquid is used as the electrolyte solution, the ionic liquid can have the functions of both an electrolyte and a solvent without including an electrolyte and a solvent. Further, as the electrolyte solution, as described above, it is only necessary that it is non-volatile and can be used as an electrolyte solution, and it may be a liquid containing an electrolyte in an ionic liquid, a liquid containing a solvent in an ionic liquid, a liquid containing an electrolyte and a solvent in an ionic liquid, or a liquid composed of an ionic liquid. Among these, as the electrolyte solution, it is preferably composed of an ionic liquid, that is, the electrolyte solution is an ionic liquid. Further, using an ionic liquid as the electrolyte solution is preferable because the ionic liquid is difficult to volatilize and has high flame retardancy. Further, the ionic liquid has relatively high ionic conductivity. From these facts, when an ionic liquid is used as the electrolyte solution, the acid gas separation device can continuously separate acid gas from a gas containing acid gas more safely and for a longer time.

[0052] The ionic liquid is not particularly limited as long as it is a known ionic liquid, and examples thereof include imidazolium-based ionic liquids, pyridine-based ionic liquids, alicyclic amine-based ionic liquids, and azonium amine-based ionic liquids.

[0053] Examples of the ionic liquid include 1-ethyl-3-methylimidazolium bis(fluorosulfonyl)imide, 1-methyl-3-octylimidazolium tetrafluoroborate, 1-ethyl-3-methylimidazolium tetrafluoroborate, 1-butyl-3-methylimidazolium chloride, 1-butyl-3-methylimidazolium tetrafluoroborate, 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, 1-decyl-3-methylimidazolium tetrafluoroborate, 1,3-dimethoxyimidazolium tetrafluoroborate, 1,3-diethoxyimidazolium tetrafluoroborate, 1-methyl-3-octylimidazolium hexafluorophosphate, 1-ethyl-3-methylimidazolium hexafluorophosphate, 1-butyl-3-methylimidazolium hexafluorophosphate, 1-decyl-3-methylimidazolium hexafluorophosphate, 1,3-dimethoxyimidazolium hexafluorophosphate, and 1,3-diethoxyimidazolium hexafluorophosphate. Among the exemplified ionic liquids, 1-ethyl-3-methylimidazolium bis(fluorosulfonyl)imide, 1-methyl-3-octylimidazolium tetrafluoroborate, 1-ethyl-3-methylimidazolium tetrafluoroborate, 1-butyl-3-methylimidazolium tetrafluoroborate, 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, 1-butyl-3-methylimidazolium chloride, 1,3-dimethoxyimidazolium tetrafluoroborate, 1-methyl-3-octylimidazolium hexafluorophosphate, and 1-ethyl-3-methylimidazolium hexafluorophosphate are preferable as the ionic liquid.In addition, as the ionic liquid, 1-ethyl-3-methylimidazolium bis(fluorosulfonyl)imide, 1-methyl-3-octylimidazolium tetrafluoroborate, 1,3-dimethoxyimidazolium tetrafluoroborate, 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, 1-butyl-3-methylimidazolium chloride, and 1-methyl-3-octylimidazolium hexafluorophosphate are more preferable, and 1-ethyl-3-methylimidazolium bis(fluorosulfonyl)imide, 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, 1-butyl-3-methylimidazolium chloride, and 1-methyl-3-octylimidazolium tetrafluoroborate are even more preferable.

[0054] As described above, the electrolyte solution is non-volatile and is not particularly limited as long as it can be used as an electrolyte solution. For example, even if it is other than an ionic liquid, an electrolyte solution containing an electrolyte and a solvent can be mentioned.

[0055] The solvent is non-volatile and is not particularly limited as long as it can be used as a solvent for the electrolyte solution. The solvent is required to be non-volatile. For example, it is preferably a solvent having a boiling point of 200°C or higher. Examples of the solvent include polyethers. Examples of the polyether include polyethylene glycol, polypropylene glycol, and polytetramethylene ether glycol. The polyether may be a homopolymer or a copolymer of these. As polyethylene glycol, polypropylene glycol, polytetramethylene ether glycol, and copolymers thereof, for example, those obtained by ring-opening polymerization using monomers such as ethylene oxide, propylene oxide, and tetrahydrofuran alone or in combination of two or more can be mentioned. From the viewpoint of fluidity, the polyether preferably has a low molecular weight, and specifically, preferably has a weight average molecular weight of about 200 to 500. The solvent may be used alone or in combination of two or more.

[0056] The electrolyte is not particularly limited, and examples thereof include quaternary ammonium salts, inorganic salts, and hydroxides. Examples of the quaternary ammonium salt include tetramethylammonium tetrafluoroborate, tetra rae butylammonium tetrafluoroborate, tetra-n-propylammonium tetrafluoroborate, tetra-n-butylammonium tetrafluoroborate, n-hexadecyltrimethylammonium tetrafluoroborate, tetra-n-hexadecylammonium tetrafluoroborate, tetra-n-octylammonium tetrafluoroborate, tetra rae butylammonium perchlorate, tetra-n-butylammonium perchlorate, and tetraoctadecylammonium perchlorate. Examples of the inorganic salt include lithium perchlorate, sodium perchlorate, potassium perchlorate, sodium acetate, potassium acetate, sodium nitrate, and potassium nitrate. Examples of the hydroxide include sodium hydroxide and potassium hydroxide. Among the electrolytes exemplified above, tetramethylammonium tetrafluoroborate, tetra trae butylammonium tetrafluoroborate, tetra-n-propylammonium tetrafluoroborate, tetra-n-butylammonium tetrafluoroborate, n-hexadecyltrimethylammonium tetrafluoroborate, tetra-n-hexadecylammonium tetrafluoroborate, tetra-n-octylammonium tetrafluoroborate, tetra rae butylammonium perchlorate, tetra-n-butylammonium perchlorate, tetraoctadecylammonium perchlorate, lithium perchlorate, sodium perchlorate, sodium acetate, and potassium acetate are preferable. Among these, tetra raeTetrafluoroborate salts such as methylammonium tetrafluoroborate, tetra-n-propylammonium tetrafluoroborate, tetra-n-butylammonium tetrafluoroborate, lithium perchlorate, and sodium perchlorate are more preferred, and tetra-n-butylammonium tetrafluoroborate and lithium perchlorate are even more preferred. Further, the electrolyte may have the ability to stabilize carbonate ions and bicarbonate ions as its supporting salt and have pH buffering ability. Specific examples of the electrolyte in this case include sodium bicarbonate, sodium carbonate, acetic acid, and sodium acetate. The electrolyte may be used alone or in combination of two or more of the above-exemplified electrolytes.

[0057] The electrolytic solution preferably has low solubility for acidic gases. In the acidic gas separation device according to the present embodiment, since the uptake of acidic gas into the electrolyte layer 13 is carried out by the binding with the reduced form of the high molecular weight redox compound, even if the electrolytic solution has low solubility for acidic gases, acidic gas can be bound to the reduced form of the high molecular weight redox compound on the surface of the electrolyte layer 13, and the acidic gas can be taken into the electrolyte layer 13. Further, when such an electrolytic solution with low solubility for acidic gases is used, when releasing the acidic gas from the electrolyte layer 13, since the acidic gas is less likely to dissolve in the electrolytic solution, the acidic gas is more likely to be released. Therefore, in the acidic gas separation device according to the present embodiment, it becomes easier to separate the acidic gas from the gas containing the acidic gas.

[0058] The electrolyte layer 13 may be a gel of the electrolytic solution. When using such an electrolyte layer composed of a gel, leakage of the electrolytic solution constituting the electrolyte layer 13 can be suppressed. Further, even if the electrolyte layer 13 is a gel containing the electrolytic solution and the high molecular weight redox compound, as described above, the acidic gas can be taken in on the first electrode side and released on the second electrode side. Therefore, it is possible to suppress the inhibition of the separation of the acidic gas from the gas containing the acidic gas due to leakage of the electrolytic solution or the like, and it can be continuously carried out for a longer time. The electrolyte composed of such a gel layerTo obtain it, for example, a gelling agent for gelling the electrolyte solution may be added, a gelled electrolyte or a polymer electrolyte may be used, or the polymer quantity The redox compound may be gelled. Further, inorganic oxides such as silica gel, alumina, titania, and zirconia may be added to the electrolyte layer. By adding an inorganic oxide, the gel can be strengthened. For example, the gelling agent can combine with the inorganic oxide to form a stronger gel. Examples of the gelling agent include polymers, gelling agents using techniques such as polymer crosslinking reactions, polymerizable polyfunctional monomers, and oil gelling agents. The gelled electrolyte and the polymer electrolyte are not particularly limited as long as they can be used as a gelled electrolyte or a polymer electrolyte. Examples thereof include vinylidene fluoride-based polymers such as polyvinylidene fluoride, acrylic acid-based polymers such as polyacrylic acid, acrylonitrile-based polymers such as polyacrylonitrile, polyether-based polymers such as polyethylene oxide, and compounds having an amide structure in the structure.

[0059] The electrolyte layer 13 may contain components other than the electrolyte solution and the high molecular weight redox compound (other components). Examples of the other components include polyethylene glycol, polyacrylate, polymethacrylate, and polyvinyl alcohol acetal.

[0060] The electrolyte layer 13 may or may not include a base material (support), but it is preferably included. Examples of the electrolyte layer 13 include those obtained by impregnating the base material (support) with the electrolyte solution containing the high molecular weight redox compound. As the base material (support), from the viewpoints of avoiding complexity in the manufacturing process, maintaining strength, and maintaining flexibility, for example, a paper-like material and a non-woven fabric are preferable, and a non-woven fabric is more preferable. The fibers constituting the non-woven fabric are not particularly limited, and examples include polyolefin fibers; cellulose fibers; (meth)acrylic fibers; polyvinyl alcohol fibers; polyvinyl chloride fibers; polystyrene fibers; polyester fibers such as polyethylene terephthalate fibers, polybutylene terephthalate fibers, polytrimethylene terephthalate fibers, and melt liquid crystal-forming wholly aromatic polyester fibers; polyamide fibers; polycarbonate fibers; and polyurethane fibers. The fibers constituting the non-woven fabric may be used alone, selected from among these, or a combination of two or more may be used. Among these fibers, those containing polyester fibers or polyvinyl alcohol fibers can be preferably applied from the viewpoint of expressing the strength of the base material (support) or the strength of the entire electrolyte layer. The polyvinyl alcohol fibers may be modified, and examples include polyvinyl alcohol fibers and ethylene-modified polyvinyl alcohol fibers. Also, when polyester fibers are included, among the above examples, melt liquid crystal-forming wholly aromatic polyester fibers can be particularly preferably applied.

[0061] Examples of the type of non-woven fabric include non-woven fabrics formed by a wet method or a dry method, melt-blown non-woven fabrics, spunlace non-woven fabrics, thermal-bonded non-woven fabrics, and non-woven fabrics formed by a needle punching method. Among these non-woven fabrics, it is preferable to use long fibers, and a melt-blown non-woven fabric is preferable. The manufacturing method of the paper-like material is not particularly limited, and those manufactured by methods such as wet papermaking can also be used.

[0062] The base material (support) can set the air permeability and film thickness by controlling the basis weight. The smaller the basis weight of the base material (support), the higher the air permeability, and components constituting the electrolyte layer such as high molecular weight redox compounds can be preferably filled. Therefore, it is preferably 2 50 g / m 2 or less, more preferably 45 g / m 2 or less, still more preferably 40 g / m 2 or less, and even more preferably 35 g / m 2 or less, 30 g / m 2 or less, 25 g / m 2 or less, 20 g / m 2 or less may also be acceptable. From the perspective of the mechanical strength of the electrolyte layer, the larger the basis weight of the base material (support), the more preferable. The basis weight of the base material (support) is preferably 1 g / m 2 or more, more preferably 2 g / m 2 or more, still more preferably 3 g / m 2 or more, and even more preferably 5 g / m 2 or more, 7 g / m 2 or more, 10 g / m 2 or more may also be acceptable.

[0063] The thickness of the base material (support) is not particularly limited, but in order to adjust the thickness of the electrolyte layer 13, it is preferably below that thickness, and usually preferably 1 μm or more, more preferably 5 μm or more, still more preferably 6 μm or more, and particularly preferably 7 μm or more. Also, the thickness of the base material (support) is preferably 1,000 μm or less, more preferably 800 μm or less, still more preferably 600 μm or less. Also, the thickness of the base material (support) may be 500 μm or less, 400 μm or less, 300 μm or less, 200 μm or less, 100 μm or less, 50 μm or less, 30 μm or less.

[0064] The manufacturing method of the electrolyte layer 13 is not particularly limited. When the electrolyte layer 13 includes the base material (support), for example, a method of dispersing or dissolving a high molecular weight redox compound in an electrolytic solution and impregnating the base material (support) with the electrolytic solution containing the high molecular weight redox compound can be mentioned. The impregnation is preferably performed while applying ultrasonic vibration to the electrolytic solution or the base material (support). By doing so, it is possible to suppress the formation of minute holes, that is, pinholes, in the electrolyte layer.

[0065] The thickness of the electrolyte layer 13 is not particularly limited as long as it is a thickness at which damage due to gas passage, pinholes, cracks, etc. does not occur. As the thickness of the electrolyte layer 13, for example, it is preferably 1 μm or more, more preferably 5 μm or more, further preferably 6 μm or more, and particularly preferably 7 μm or more. Also, as the thickness of the electrolyte layer 13, for example, it is preferably 1000 μm or less, more preferably 800 μm or less, and further preferably 600 μm or less. Also, the thickness of the electrolyte layer 13 may be 550 μm or less, 500 μm or less, 450 μm or less, 400 μm or less, 350 μm or less, 250 μm or less, 150 μm or less, 100 μm or less, 80 μm or less, 40 μm or less, 30 μm or less. When the thickness of the electrolyte layer 13 is equal to or greater than the above lower limit, complication in the manufacturing process of the acid gas separation device can be suppressed. When the thickness of the electrolyte layer 13 is equal to or less than the above upper limit, it is easy to reduce the voltage used for the transfer of the acid gas (the voltage applied between a pair of electrodes to separate the acid gas).

[0066] The difference between the thickness of the electrolyte layer 13 and the thickness of the support (the difference obtained by subtracting the thickness of the support from the thickness of the electrolyte layer 13: thickness of the electrolyte layer - thickness of the support) is not particularly limited and may be 0 μm, but when it is greater than 0 μm, the adhesion between the electrode and the electrolyte layer is improved, and as a result, the transfer efficiency of the acid gas can be increased. The difference obtained by subtracting the thickness of the support from the thickness of the electrolyte layer 13 is preferably 1 μm or more and 500 μm or less. With such an electrolyte layer having such a difference, the transfer efficiency of the acid gas can be increased, and the acid gas can be more preferably separated from the gas containing the acid gas.

[0067] The ratio of the thickness of the support to the thickness of the electrolyte layer 13 (thickness of the support / thickness of the electrolyte layer) is not particularly limited. From the viewpoint of improving the adhesion between the electrolyte layer and the electrode, the ratio of the thickness of the support to the thickness of the electrolyte layer is preferably 1 or less, and preferably 0.99 or less. Further, the ratio of the thickness of the support to the thickness of the electrolyte layer 13 is preferably 0.3 or more, and preferably 0.4 or more, from the viewpoint of achieving both maintenance of the strength of the electrolyte layer and the separation and the electrolyte layer.

[0068] Next, a pair of electrodes (electrodes 11, 12), which is one of the constituent components of the acid gas separation device according to the present embodiment, will be described.

[0069] The pair of electrodes 11, 12 is not particularly limited as long as it is an electrode through which gas can permeate. That is, the electrodes 11, 12 may be a conductive member that can permeate a gas such as carbon dioxide and can pass an electric current through the electrolyte layer 13 sandwiched between the pair of electrodes 11, 12. Further, the electrodes 11, 12 are preferably a porous body having conductivity to such an extent that it does not inhibit the movement of electrons and excellent air permeability. Specifically, electrodes composed of a porous conductive material and the like can be mentioned. More specifically, as the electrodes 11, 12, a porous body containing carbon as a main component, a porous body made of carbon, and a porous metal layer and the like can be mentioned. Examples of the porous conductive material include porous metal, a porous body containing carbon as a main component, and a porous body made of carbon. These porous conductive materials may be used alone or in combination of two or more. That is, as the pair of electrodes 11, 12, an electrode composed of a single conductive material among these porous conductive materials may be used, or an electrode composed of a combination of two or more conductive materials may be used.

[0070] The porous metal layer is a metal layer in which a large number of pores are formed. Further, from the viewpoint of excellent air permeability, it is preferable that the pores are formed throughout the metal layer. Further, as a method for obtaining the porous metal layer, any method (a method of making it porous) for performing a process of forming a large number of pores on a metal layer in which a large number of pores are not formed is not particularly limited. Examples of this method include physical methods such as cutting, polishing, and sandblasting, and chemical methods such as electrolytic etching and electroless etching using an etching solution such as an acid or a base. Further, as a method for making it porous, each of the above methods may be performed alone, or two or more of them may be combined. Further, from the viewpoint of increasing the surface area, in order to form the pores (fine pores) to be formed more densely, a chemical method is preferable. Further, the material of the metal layer is not particularly limited, and examples thereof include aluminum, copper, silver, gold, iron, titanium, molybdenum, tungsten, nickel, and alloys thereof. Examples of the alloy include stainless steel. Among these, from the viewpoints of durability and workability, the material of the metal layer is preferably copper, silver, titanium, SUS316, or SUS321.

[0071] Specific examples of the carbon contained in the porous body include carbonaceous materials such as graphite, carbon nanotubes, activated carbon, activated carbon fibers, and carbon fibers. Further, from the viewpoints of corrosion resistance and specific surface area, activated carbon or activated carbon fibers are preferable as this carbon. Further, as this carbon, various carbonaceous materials may be used alone, or two or more of them may be combined. As the porous body containing this carbon, those obtained by forming the carbonaceous material into a cloth shape or a felt shape are preferable. Therefore, specific examples of the electrode that is a porous body include a carbon sheet, a carbon cloth, and a carbon paper. Further, examples of the electrode that is a porous body also include a carbon-based electrode using activated carbon or carbon fibers, and an electrode with a high porosity using a needle-shaped conductive material.

[0072] As the pair of electrodes 11 and 12, among the above-mentioned electrodes, it is preferable that they are electrodes containing at least one selected from the group consisting of porous metal, graphite, carbon nanotubes, and carbon fibers. With such electrodes, it is considered that gas can permeate preferably and a voltage can be preferably applied between the electrodes 11 and 12 by the voltage application unit 14. Therefore, by using this electrode, an acidic gas separation device capable of more preferably separating acidic gas from a gas containing acidic gas can be obtained.

[0073] When the porous bodies constituting the pair of electrodes 11 and 12 are in a particulate state, they can be polarized by molding them into a sheet shape using a binder, or they can be formed and molded by forming a film on a conductive mesh. The binder that can be used is not particularly limited, and examples include PVDF (polyvinylidene fluoride), polytetrafluoroethylene, and a mixture of SBR (styrene-butadiene rubber) and CMC (carboxymethyl cellulose), polyacrylic acid, acrylic acid, a copolymer of acrylonitrile, polyvinyl alcohol, and its partially modified products, etc.

[0074] When forming a film of particulate porous bodies on a mesh-like conductor, as the mesh that can be used, a mesh made of fine wires such as iron, nickel, and stainless steel, expanded metal obtained from a metal foil, or a paper or non-woven fabric made of synthetic fibers or natural fibers with conductive plating can be used.

[0075] The thickness of the mesh is not particularly limited, but in order to adjust the thickness of the electrodes 11 and 12, it is preferably below that thickness. Usually, the thickness of the mesh is preferably 5 μm to 1 mm, more preferably 6 μm to 800 μm, and even more preferably 7 μm to 600 μm.

[0076] The BET specific surface area of the electrodes 11 and 12 is not particularly limited, but for example, it is preferably 1 m 2 / g or more, more preferably 100 m 2 / g or more, and even more preferably 500 m 2More preferably, it is 1 g or more. From the viewpoint of gas permeability (ventilation property), the BET specific surface area of the electrodes 11 and 12 is preferably larger, but from the relationship of the strength of each electrode 11 and 12, etc., it is preferably 3000 m 2 / g or less. Therefore, the BET specific surface area of the electrodes 11 and 12 is preferably 1 to 3000 m 2 / g, more preferably 100 to 2500 m 2 / g, and even more preferably 500 to 2000 m 2 / g. If the BET specific surface area of the electrode is too small, the gas permeability (ventilation property) tends to decrease, and the permeation of carbon dioxide is likely to be inhibited. On the other hand, if the BET specific surface area of the electrode is too large, the strength of the electrode and the like tend to become insufficient. From these facts, if the BET specific surface area of the electrode is within the above range, carbon dioxide separation can be repeatedly realized over a long period of time. The BET specific surface area is the specific surface area measured by the BET method and can be measured by a known method. Examples of the method for measuring the BET specific surface area include a method of performing nitrogen adsorption isotherm measurement and calculating from the obtained adsorption isotherm.

[0077] As described above, the electrodes 11 and 12 are conductive members that can pass an electric current through the electrolyte layer 13 sandwiched between the pair of electrodes 11 and 12. The surface resistance value thereof is preferably as small as possible. For example, it is preferably 1 kΩ / sq or less, and more preferably 200 Ω / sq or less. Also, although the surface resistance value of the electrode is preferably as small as possible, in practice, the limit is 1 Ω / sq. Therefore, the surface resistance value of the electrode is preferably 1 Ω / sq to 1 kΩ / sq, and more preferably 10 to 200 Ω / sq. With an electrode having such a surface resistance value, an electric current can be suitably passed through the electrolyte layer 13, and carbon dioxide can be suitably separated.

[0078] The thickness of the electrodes 11 and 12 is not particularly limited, but it is preferably a thickness that can adsorb carbon dioxide and can suitably prevent leakage of the electrolytic solution. The thickness of the electrodes 11 and 12 is, for example, preferably 20 μm or more and 10 mm or less, more preferably 50 μm or more and 5 mm belowIt is more preferable that it is so. If each of the electrodes is too thin, the strength of the electrode and the like tend to be insufficient. Also, if the electrode is too thick, the gas permeability (ventilation property) decreases, and the permeation of carbon dioxide tends to be inhibited. From these facts, if the thickness of the electrode is within the above range, carbon dioxide separation can be repeatedly realized over a long period of time.

[0079] Moreover, the voltage application unit 14 is not particularly limited as long as it can apply a voltage between the pair of electrodes 11 and 12. That is, as described above, the voltage application unit 14 applies a voltage between the pair of electrodes 11 and 12 so as to increase the potential of either electrode between the pair of electrodes 11 and 12. Further, it is preferable that the voltage application unit 14 applies a voltage so that the potential of the first electrode on the side that takes in the acidic gas from the gas containing the acidic gas is always lower than that of the second electrode on the side that releases the acidic gas from the electrolyte layer. By doing so, by simply applying a voltage with the voltage application unit so that the potential of the first electrode is always lower than the potential of the second electrode, the acidic gas can be taken in on the first electrode side and the acidic gas can be released on the second electrode side. Also, the voltage application unit 14 may be an application unit that cannot reverse the voltage applied between the electrodes. For example, a secondary battery, an external power source, a capacitor, and the like can be mentioned.

[0080] Moreover, the first flow path 15 and the second flow path 16 are not particularly limited as long as they are flow paths through which gas can flow.

[0081] The acidic gas separation device 10 according to the present embodiment is not particularly limited in its manufacturing method as long as it can manufacture the device having the above structure. Specifically, a general assembling method such as assembling using a pair of electrodes 11 and 12, an electrolyte layer 13, a voltage application unit 14, a first flow path 15, and a second flow path 16 so as to have the structure shown in FIG. 1 can be mentioned.

[0082] Examples of the acidic gas include carbon dioxide, NOx (nitrogen oxides), SOx (sulfur oxides), and hydrogen sulfide. Also, the acidic gas may contain one type of acidic gas or may contain two or more types of acidic gases.

[0083] The installation location of the acid gas separation device according to this embodiment is not particularly limited as long as it is a location where acid gas separation is required. Further, it may be used as a device equipped with an acid gas separation device. Examples of the device equipped with an acid gas separation device include an air purifier, an air conditioner, and an acid gas concentrator. More specifically, an acid gas concentrator for separating and concentrating acid gas in the air can be mentioned, for example, it can be used for agricultural use or the like. Further, in order to separate and remove acid gas in a room, examples of the device equipped with the acid gas separation device include an air purifier and an air conditioner. These can be used to adjust the acid gas concentration in private cars, buses, trains, airplanes, space stations, etc.

[0084] An air purifier according to another embodiment of the present invention is an air purifier provided with the acidic gas separation device. Examples of the air purifier according to this embodiment include the air purifier 20 shown in FIG. 2. The air purifier 20 includes a dust collection and deodorization filter 21, an acidic gas separation device 10, and a fan 22. The dust collection and deodorization filter 21 is not particularly limited as long as it can perform a dust collection process for removing house dust and the like from the gas and a deodorization process for deodorizing the gas by passing the supplied gas such as air, and examples include dust collection and deodorization filters provided in general air purifiers. The fan 22 is not particularly limited as long as it can flow the gas from which the acidic gas has been removed by the acidic gas separation device 10 to the place where the air purifier 20 is installed, such as indoors. The air purifier 20 supplies the air that has been subjected to the dust collection process and the deodorization process by the dust collection and deodorization filter 21 to the acidic gas separation device 10, separates the acidic gas by the acidic gas separation device 10, and flows the gas from which the acidic gas has been separated to the place where the air purifier 20 is installed, such as indoors, by the fan 22. By doing so, the air purifier 20 can supply the air that has been subjected to the dust collection process and the deodorization process and has a reduced acidic gas concentration to the place where the air purifier 20 is installed, such as indoors. That is, the air purifier 20 can separate the acidic gas by the acidic gas separation device 10, and by removing the separated acidic gas, the concentration of the acidic gas contained in the gas such as air supplied from the air purifier 20 can be reduced. Further, the air purifier according to this embodiment is not particularly limited as long as it is provided with the acidic gas separation device, and is not limited to the air purifier that supplies the gas such as air that has been subjected to the dust collection process and the deodorization process by the dust collection and deodorization filter 21 as described above to the acidic gas separation device 10. Examples of the air purifier according to this embodiment include, for example, the above-mentioned acidic gas sub - minute An air purifier that supplies the gas from which the acidic gas has been removed by the separation device to the dust collection and deodorization filter, and performs a dust collection process and a deodorization process on the gas by the dust collection and deodorization filter may be used.

[0085] An air conditioner according to another embodiment of the present invention is an air conditioner provided with the acid gas separation device. Examples of the air conditioner according to this embodiment include the air conditioner 30 shown in FIG. 3. The air conditioner 30 includes an indoor unit 31 and an outdoor unit 32. The indoor unit 31 is not particularly limited as long as it includes the acid gas separation device 10. For example, it may be an indoor unit similar to a general air conditioner indoor unit except that it includes the acid gas separation device 10. Also, the outdoor unit 32 is not particularly limited, and examples include a general air conditioner outdoor unit. The indoor unit 31 includes a heat exchanger 33, the acid gas separation device 10, and a fan 34. The heat exchanger 33 is not particularly limited as long as it operates together with the outdoor unit 32 and can adjust the temperature of a gas such as supplied air by lowering (cooling) or raising (heating) the temperature, and examples include heat exchangers provided in general air conditioners. The fan 34 is not particularly limited as long as it can cause the gas from which the acid gas has been removed by the acid gas separation device 10 to flow to the location (such as indoors) where the indoor unit 31 of the air conditioner 30 is installed. The outdoor unit 32, together with the heat exchanger 33, cools or heats the temperature of a refrigerant or the like that has been heated or cooled when the temperature of a gas such as air supplied to the heat exchanger 33 is lowered (cooled) or raised (heated) on the outdoor unit side. At that time, the fan 35 provided in the outdoor unit 32 discharges the gas inside the outdoor unit 32 to the outside of the outdoor unit 32. The air conditioner 30 supplies the air whose temperature has been adjusted by the heat exchanger 33 and the outdoor unit 32 to the acid gas separation device 10, separates the acid gas by the acid gas separation device 10, and causes the gas from which the acid gas has been separated to flow to the location (such as indoors) where the indoor unit 31 of the air conditioner 30 is installed by the fan 34. By doing so, air whose temperature has been adjusted and whose acid gas concentration has been reduced can be supplied to the location (such as indoors) where the indoor unit 31 of the air conditioner 30 is installed. That is, the air conditioner 30 can separate the acid gas with the acid gas separation device 10, and by removing the separated acid gas, the acid gas concentration contained in a gas such as air supplied from the air conditioner 30 can be reduced.Further, if the air conditioner is provided with the acidic gas separation device, it is not particularly limited, and is not limited to the air conditioner that supplies a gas such as air whose temperature is adjusted by the heat exchanger 33 and the outdoor unit 32 to the acidic gas separation device 10 as described above. The air conditioner according to the present embodiment may be, for example, an air conditioner that supplies a gas from which acidic gas has been removed by the acidic gas separation device to a heat exchanger and adjusts the temperature of the gas with the heat exchanger and the outdoor unit.

[0086] The acidic gas concentration device according to another embodiment of the present invention is an acidic gas concentration device provided with the acidic gas separation device. Examples of the acidic gas concentration device include the acidic gas separation device 10 shown in FIG. 1. Note that FIG. 1 is also a schematic diagram showing the configuration of an acidic gas concentration device provided with an acidic gas separation device according to an embodiment of the present invention. By the acidic gas separation device 10, a gas containing acidic gas such as air is supplied to the first flow path 15, and a gas with an increased acidic gas concentration can be discharged from the second flow path 16. If the gas (gas with an increased acidic gas concentration) discharged from the second flow path 16 of the acidic gas separation device 10 is recovered, the acidic gas can be concentrated. Therefore, this acidic gas separation device 10 becomes an acidic gas concentration device provided with the acidic gas separation device. Therefore, the acidic gas concentration device can separate acidic gas with the acidic gas separation device and concentrate the acidic gas by recovering the separated acidic gas. Further, the acidic gas concentration device only needs to be provided with the acidic gas separation device, and may be provided with other members.

[0087] Among such acidic gas concentration devices, if the acidic gas is carbon dioxide, it can be applied as a carbon dioxide concentration device. The demand for carbon dioxide concentration devices is increasing in agricultural applications and the like. Specifically, it can be applied to applications such as promoting plant growth by concentrating carbon dioxide in the air and supplying it to a greenhouse. It can also be applied to CA storage applications such as improving storage properties by concentrating carbon dioxide in the air and increasing the carbon dioxide concentration in a fruit and vegetable storage.

[0088] As described above, this specification discloses technologies in various aspects, and the main technologies are summarized below.

[0089] One aspect of the present invention includes an electrolyte layer, a pair of electrodes provided with the electrolyte layer interposed therebetween, and a voltage application unit that applies a voltage between the pair of electrodes. The pair of electrodes are each an electrode that can permeate gas, and the electrolyte layer includes at least one selected from the group consisting of a high molecular weight redox compound having a radicalization rate of 90% or more, a high molecular weight redox compound having a quinone group in the molecule, and a high molecular weight redox compound having an imino group in the molecule, and a non-volatile electrolytic solution. It is an acidic gas separation device characterized by this.

[0090] According to such a configuration, it is possible to provide an acidic gas separation device that can easily separate acidic gas from a gas containing acidic gas and can repeat this separation over a long period. In the acidic gas separation device, for example, a voltage is applied between a pair of electrodes so that the potential of one electrode is lower than the potential of the other electrode. By applying a voltage in this way, on the side closer to the electrode with the lower potential, the high molecular weight redox compound contained in the electrolyte layer is electrolytically reduced to become a reduced form. It is considered that the acidic gas in contact with the surface of the electrolyte layer is combined with this reduced form and taken into the electrolyte layer. Also, on the side closer to the other electrode with the higher potential, the high molecular weight redox compound contained in the electrolyte layer is electrolytically oxidized to become a radical form or an oxidized form. Therefore, if an acid property gas is bound to the high molecular weight redox compound, this acid propertyIt is considered that gas is desorbed from the high molecular weight redox compound and released from the electrolyte layer (the surface side on the other electrode side). Therefore, it is considered that the acidic gas separation device can take in carbon dioxide on the one electrode side and release carbon dioxide on the other electrode side. Further, in the acidic gas separation device, since the redox compound contained in the electrolyte layer has a high molecular weight and the electrolytic solution is non-volatile, it is considered that the separation of acidic gas from the gas containing acidic gas can be carried out over a long period of time.

[0091] From the above, it is considered that acidic gas can be easily separated from the gas containing acidic gas, and this separation can be repeated over a long period of time.

[0092] Further, in the acidic gas separation device, the pair of electrodes is composed of a first electrode on the side that takes in acidic gas from the gas containing acidic gas and a second electrode on the side that releases acidic gas from the electrolyte layer, and the voltage application unit preferably applies a voltage between the pair of electrodes so that the potential of the first electrode is lower than the potential of the second electrode.

[0093] According to such a configuration, by simply applying a voltage between the pair of electrodes (between the first electrode and the second electrode), acidic gas can be continuously separated from the gas containing acidic gas without inverting the voltage applied between the pair of electrodes. Note that continuously performing this separation (continuous operation) may inhibit the volatilization of the electrolytic solution or the redox compound constituting the electrolyte layer. However, in the case of the acidic gas separation device, as described above, since the redox compound contained in the electrolyte layer has a high molecular weight and the electrolytic solution is non-volatile, the separation of acidic gas from the gas containing acidic gas can be continuously carried out over a longer period of time. Therefore, the acidic gas separation device can more easily separate acidic gas from the gas containing acidic gas, and this separation can be repeated over a longer period of time.

[0094] In addition, in the acid gas separation device, the thickness of the electrolyte layer is 1 μm or more and 1,000 μm below or less, which is preferable.

[0095] According to such a configuration, the acid gas can be easily separated from the gas containing the acid gas, and this separation can be repeated over a long period. Furthermore, the acid gas separation device can be easily manufactured, and even if the voltage applied between the pair of electrodes is reduced, the acid gas can be suitably separated from the gas containing the acid gas.

[0096] In addition, in the acid gas separation device, it is preferable that the electrolyte layer further includes a support.

[0097] According to such a configuration, the electrolyte layer provided in the acid gas separation device becomes an electrolyte layer in a suitable state such as having high mechanical strength. Therefore, by providing this electrolyte layer, an acid gas separation device capable of easily separating the acid gas from the gas containing the acid gas and repeating this separation over a long period can be suitably obtained.

[0098] In addition, in the acid gas separation device, the thickness of the support is preferably 1 μm or more and 1,000 μm below or less.

[0099] According to such a configuration, since the electrolyte layer provided in the acid gas separation device becomes an electrolyte layer in a more suitable state, the acid gas separation device can be obtained more suitably.

[0100] In addition, in the acid gas separation device, the difference obtained by subtracting the thickness of the support from the thickness of the electrolyte layer is preferably 1 μm or more and 500 μm or less.

[0101] According to such a configuration, the acid gas can be more suitably separated from the gas containing the acid gas. This is considered to be because, in the acid gas separation device, the adhesion between the electrode and the electrolyte layer is improved, and as a result, the transfer efficiency of the acid gas can be increased.

[0102] Further, in the acid gas separation device, it is preferable that the ratio of the thickness of the support to the thickness of the electrolyte layer is 0.3 or more and 0.99 or less.

[0103] According to such a configuration, the acid gas can be more suitably separated from the gas containing the acid gas. This is considered to be because, in the acid gas separation device, the adhesion between the electrode and the electrolyte layer is improved, and as a result, the transfer efficiency of the acid gas can be increased. Furthermore, since the strength of the electrolyte layer provided in the acid gas separation device can be increased, the acid gas separation device can achieve both the maintenance of the strength of the electrolyte layer and the separation.

[0104] Further, in the acid gas separation device, it is preferable that the basis weight of the support is 1 g / m 2 or more and 50 g / m 2 or less.

[0105] According to such a configuration, since the electrolyte layer provided in the acid gas separation device becomes an electrolyte layer in a more suitable state, the acid gas separation device can be obtained more suitably. This is considered to be because not only the air permeability of the support is high and the support can be suitably filled with components constituting the electrolyte layer such as high molecular weight redox compounds, but also the mechanical strength of the support is high, so that the mechanical strength of the electrolyte layer can be improved.

[0106] Further, in the acid gas separation device, it is preferable that the support is a nonwoven fabric.

[0107] According to such a configuration, since the electrolyte layer provided in the acid gas separation device becomes a more suitable electrolyte layer, the acid gas separation device can be obtained more suitably. This is considered to be due to the fact that when the support is a nonwoven fabric, it is excellent in terms of avoiding complexity in the manufacturing process, maintaining strength, and maintaining flexibility.

[0108] Further, in the acid gas separation device, it is preferable that the fibers constituting the nonwoven fabric contain at least one selected from the group consisting of polyolefin fibers, cellulose fibers, (meth)acrylic fibers, polyvinyl alcohol fibers, polyvinyl chloride fibers, polystyrene fibers, polyester fibers, polyamide fibers, polycarbonate fibers, and polyurethane fibers.

[0109] According to such a configuration, since the electrolyte layer provided in the acid gas separation device becomes a more suitable electrolyte layer, the acid gas separation device can be obtained more suitably.

[0110] Further, in the acid gas separation device, it is preferable that the weight average molecular weight of the high molecular weight redox compound is 1,000 or more.

[0111] According to such a configuration, the separation of acid gas from the gas containing acid gas can be repeated over a longer period.

[0112] Further, in the acid gas separation device, it is preferable that the high molecular weight redox compound having a radicalization rate of 90% or more has a repeating unit represented by the following formula (1) in the molecule.

[0113]

Chemical formula

[0114] According to such a configuration, acid gas can be separated more suitably from the gas containing acid gas.

[0115] Moreover, an air purifier according to another aspect of the present invention is an air purifier provided with the acidic gas separation device.

[0116] According to such a configuration, the acidic gas separation device can separate acidic gas from a gas containing acidic gas, and by removing the separated acidic gas, the concentration of acidic gas contained in the gas supplied from the air purifier can be reduced.

[0117] Moreover, an air conditioner according to another aspect of the present invention is an air conditioner provided with the acidic gas separation device.

[0118] According to such a configuration, the acidic gas separation device can separate acidic gas from a gas containing acidic gas, and by removing the separated acidic gas, the concentration of acidic gas contained in the gas supplied from the air conditioner can be reduced.

[0119] Moreover, an acidic gas concentrator according to another aspect of the present invention is an acidic gas concentrator provided with the acidic gas separation device.

[0120] According to such a configuration, the acidic gas separation device can separate acidic gas from a gas containing acidic gas, and by recovering the separated acidic gas, the acidic gas can be concentrated.

[0121] According to the present invention, an acidic gas separation device that can easily separate acidic gas from a gas containing acidic gas and can repeat this separation over a long period can be provided. Specifically, when a gas containing acidic gas is supplied to one electrode side of the acidic gas separation device, the acidic gas can be preferentially released from the other electrode side. Moreover, according to the present invention, an air purifier, an air conditioner, and an acidic gas concentrator provided with the acidic gas separation device are provided.

[0122] Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto.

Example

[0123] [Example 1] <Preparation of Acid Gas Separation Device> An acid gas separation device having the structure shown in FIG. 1 was prepared by the following procedure.

[0124] (Preparation of High Molecular Weight Redox Compound) To a 200 mL Erlenmeyer flask, 22.5 g (100 mmol) of 2,2,6,6-tetramethyl-4-piperidinyl methacrylate and 25 mL of methanol as a solvent were added and mixed to obtain a homogeneous solution. To a 500 mL four-necked flask equipped with a stirrer, a nitrogen gas inlet tube, a thermometer, and a reflux condenser, 164 mg (1.00 mmol) of 2,2'-azobis-2,4-dimethylvaleronitrile as a polymerization initiator and 200 mL of methanol were added. While maintaining this solution at 25°C, the homogeneous solution was added and mixed with stirring. Subsequently, after removing oxygen in the reaction system through nitrogen gas, the polymerization solution was reacted for 6 hours while maintaining it at 65°C with stirring. After completion of the reaction, the reaction solution was cooled to room temperature and 500 mL of water was added. The solid obtained by filtration was washed with 300 mL of water and then 500 mL of hexane, and dried under reduced pressure to obtain 22.0 g of a polymerization reaction product.

[0125] Next, 10 g of the polymerization reaction product obtained in the above step, 0.73 g (2.2 mmol) of sodium tungstate dihydrate as a catalyst, and 300 mL of methanol were charged into a 500 mL four-necked flask equipped with a stirrer, a nitrogen gas inlet tube, a thermometer, a reflux condenser, and a dropping funnel. After removing oxygen in the reaction system through nitrogen gas while maintaining it at 25°C, 25.2 g (222 mmol) of 30% hydrogen peroxide solution was added dropwise over 3 hours. Subsequently, the reaction was carried out at 40°C for 8 hours. After completion of the reaction, the reaction solution was cooled to room temperature and 500 mL of water was added. The solid obtained by filtration was washed with 300 mL of water and dried under reduced pressure to obtain 10.2 g of a red solid. This red solid was a high molecular weight redox compound.

[0126] (Measurement of Weight-Average Molecular Weight) The obtained high-molecular-weight redox compound was subjected to GPC measurement under the following conditions using a gel permeation chromatography apparatus manufactured by Shimadzu Corporation, and as a result of determining the weight-average molecular weight (Mw), it was 79,000.

[0127] Column: Two "KF-806M" tetrahydrofuran-based columns manufactured by Showa Denko K.K. connected in series Standard sample: Polymethyl methacrylate Solvent and mobile phase: Tetrahydrofuran (THF) (concentration 20 mM) Flow rate: 1.0 mL / min Temperature: 40 °C Sample solution concentration: 0.2 wt% (filtered with a 0.45 μm aperture filter) Injection volume: 100 μL Detector: RI

[0128] (Measurement of Radicalization Rate by Chemical Titration Method) The content of the repeating unit represented by the formula (1) in the high-molecular-weight redox compound was measured by a chemical titration method (redox titration method) based on a redox reaction, and from the obtained content, the content ratio (radicalization rate) of the above (1) was calculated. Specifically, 100 mg of a sample (high-molecular-weight redox compound) was weighed, dissolved in chloroform and acetic acid, then an aqueous solution of 0.2 N potassium iodide was added, and the liberated iodine was back-titrated with an aqueous solution of 0.05 N sodium thiosulfate. The test was analyzed with 2 specimens, and the average value was taken as the analytical value (radicalization rate). As a result, the radicalization rate of the obtained high-molecular-weight redox compound was 99%.

[0129] (Preparation of Support A) A melt liquid crystal-forming wholly aromatic polyester composed of a copolymer of p-hydroxybenzoic acid and 6-hydroxy-2-naphthoic acid was extruded by a twin-screw extruder, supplied to a melt blown nonwoven fabric manufacturing apparatus, extruded at a single-hole discharge rate of 0.10 g / min and a resin temperature of 330 °C, and had a basis weight of 15 g / m 2After obtaining the non-woven fabric, the obtained non-woven fabric was heat-treated at 300 °C for 6 hours. Then, the obtained non-woven fabric was passed between a metal roll heated to 110 °C and an elastic roll made of resin, and further continuously processed using a calendering machine. The average fiber diameter of the obtained meltblown non-woven fabric was 2.8 μm, and the basis weight was 15 g / m 2 as described above, and a meltblown non-woven fabric with a thickness of 25 μm was obtained. This obtained non-woven fabric was used as the support A.

[0130] (Electrolyte layer (acid gas separator)) First, the support A was fixed on a glass plate.

[0131] To 100.0 g of dimethylformamide (manufactured by FUJIFILM Wako Pure Chemical Corporation), 6.0 g of Poly(vinylidenefluoride-co-hexafluoropropylene) (manufactured by Sigma-Aldrich) was added and dissolved by stirring at 80 °C for 3 hours. Next, 2.00 g of a high molecular weight redox compound (a high molecular weight redox compound with a radicalization rate of 90% or more) was added to the obtained solution and dissolved by stirring at 80 °C for 1 hour. Next, 12.0 g of an ionic liquid [1-ethyl-3-methylimidazolium bis(fluorosulfonyl)imide (emimFSI manufactured by Sigma-Aldrich)], which is a non-volatile electrolyte solution, was added to the obtained solution, heated to 40 °C, and stirred and mixed for 3 hours. Using the liquid thus obtained, a liquid film with a thickness (coating thickness from the glass plate) of 600 μm was formed on the support A fixed on the glass plate using an applicator, and dried under reduced pressure at 60 °C for 8 hours. The dried film obtained by the drying was peeled off from the glass plate. By doing so, a dried film with a support having a thickness of 50 μm was obtained as the electrolyte layer. The thickness of the support contained in this electrolyte layer was 25 μm. The difference obtained by subtracting the thickness of the support from the thickness of the electrolyte layer was 25 μm, and the ratio of the thickness of the support to the thickness of the electrolyte layer (thickness of the support / thickness of the electrolyte layer) was 0.5.

[0132] (Electrode) Carbon paper (TGP-H-030 manufactured by Toray Industries, Inc.) was cut into pieces with a size of 20 mm in length × 20 mm in width × 0.1 mm in thickness. A conductive copper foil tape was attached to one surface of the cut carbon paper. Two such pieces were prepared and used as each electrode (cathode electrode and anode electrode).

[0133] (Flow path) A resin plate made of polytetrafluoroethylene was cut into pieces with a size of 50 mm in length × 50 mm in width × 5 mm in thickness, and two holes were drilled at appropriate positions. A groove with a depth of 1 mm × 20 mm in length × 20 mm in width, which is connected to the holes, was dug in the cut resin plate. Two such pieces were prepared and used as each flow path (first flow path and second flow path).

[0134] (Acid gas separation device) The electrolyte layer, the electrodes, and the flow paths were assembled so as to have the structure shown in FIG. 1, and a power source as a voltage application unit was connected to the conductive copper foil tape of the electrode. By doing so, an acid gas separation device having the structure shown in FIG. 1 was manufactured.

[0135] <Evaluation> The acid gas separation device was evaluated by the following evaluation method. Here, carbon dioxide (CO2) was used as the acid gas for evaluation. That is, as the gas containing the acid gas, a gas containing carbon dioxide was used.

[0136] First, the acid gas separation device was installed in an environment at 25°C. Then, a 1L gas bag filled with carbon dioxide so that the carbon dioxide concentration became 2000 ppm and an air pump were attached to the hole of the flow path on the cathode electrode side so as to circulate inside the flow path on the cathode electrode side. Also, a 1L gas bag filled with carbon dioxide so that the carbon dioxide concentration became 400 ppm and an air pump were attached to the hole of the flow path on the anode electrode side so as to circulate inside the flow path on the anode electrode side. The carbon dioxide concentration of each gasIt was measured with a portable carbon dioxide gas concentration meter (FUSO-77535 manufactured by FUSO Co., Ltd.) placed inside the bag. Then, by adjusting the power supply, a voltage of 3.0 V was applied between the electrodes. After applying the voltage, the gas in the gas bag was circulated through the flow paths of the respective electrodes at a flow rate of 500 mL / min by air pumps attached to each of the flow paths on the cathode electrode side and the anode electrode side. By doing so, the gas in the gas bag was continuously passed through the flow paths of the respective electrodes at a flow rate of 500 mL / min. The carbon dioxide concentration after 60 minutes was measured. As a result, the carbon dioxide concentration in the flow path on the cathode electrode side was 150 ppm. This evaluation test was repeated 10 times for the same electrolyte membrane, and after the 10th evaluation test, the carbon dioxide concentration in the flow path on the cathode electrode side was 160 ppm. These results are shown in Table 1.

[0137] [Example 2] As the polymerization initiator, 268 milligrams (2.00 millimoles) of 2,2'-azobis-2,4-dimethylvaleronitrile was used, toluene was used instead of methanol, and the polymerization solution was reacted for 3 hours while maintaining the temperature at 110°C instead of reacting for 6 hours while maintaining the temperature at 65°C. Otherwise, in the same manner as in Example 1, a high molecular weight redox compound was prepared. The weight average molecular weight of the obtained high molecular weight redox compound was measured by the same method as in Example 1 and was found to be 2,100. Also, the radicalization rate of the high molecular weight redox compound was measured by the same method as in Example 1 and was found to be 98 mass%.

[0138] An acidic gas separation device was produced in the same manner as in Example 1, except that the obtained high molecular weight redox compound (a high molecular weight redox compound with a radicalization rate of 90% or more) was used. The electrolyte layer contained in this acidic gas separation device had a thickness of 50 μm. The thickness of the support contained in the electrolyte layer was 25 μm. The difference obtained by subtracting the thickness of the support from the thickness of the electrolyte layer was 25 μm, and the ratio of the thickness of the support to the thickness of the electrolyte layer (thickness of the support / thickness of the electrolyte layer) was 0.5. Then, using the obtained acidic gas separation device, the same evaluation as in Example 1 was performed. The results are shown in Table 1.

[0139] [Example 3] A high molecular weight redox compound was prepared in the same manner as in Example 1, except that 55 milligrams (0.67 millimoles) of 2,2’-azobis-2,4-dimethylvaleronitrile was used as the polymerization initiator and the polymerization solution was reacted for 12 hours instead of 6 hours. The weight average molecular weight of the obtained high molecular weight redox compound was measured by the same method as in Example 1 and was found to be 310,000. Also, the radicalization rate of the high molecular weight redox compound was measured by the same method as in Example 1 and was found to be 97%.

[0140] An acidic gas separation device was produced in the same manner as in Example 1, except that the obtained high molecular weight redox compound (a high molecular weight redox compound with a radicalization rate of 90% or more) was used. The electrolyte layer contained in this acidic gas separation device had a thickness of 50 μm. The thickness of the support contained in the electrolyte layer was 25 μm. The difference obtained by subtracting the thickness of the support from the thickness of the electrolyte layer was 25 μm, and the ratio of the thickness of the support to the thickness of the electrolyte layer (thickness of the support / thickness of the electrolyte layer) was 0.5. Then, using the obtained acidic gas separation device, the same evaluation as in Example 1 was performed. The results are shown in Table 1.

[0141] [Example 4] Into a three-necked flask with an internal volume of 50 mL, 1.51 g (5.45 mmol) of 1,4-dichloroanthraquinone and 20 mL of dehydrated dimethylformamide were added and mixed under nitrogen to obtain a homogeneous solution. Next, into a 300 mL four-necked flask equipped with a stirrer, a nitrogen gas inlet tube, a thermometer, and a reflux condenser, 1.51 g (5.45 mmol) of 1,4-dichloroanthraquinone, 1.13 g (7.27 mmol) of 2,2'-bipyridyl nickel(0) bis(1,5-cyclooctadiene), 590 mg (5.45 mmol) of 1,5-cyclooctadiene, and 50 mL of dehydrated dimethylformamide were mixed under nitrogen. While maintaining this mixed solution at 65 °C and stirring, the above homogeneous solution was added dropwise over 30 minutes. After reacting the reaction solution at 65 °C for 48 hours, the reaction solution was cooled to room temperature, 100 mL of 1 M hydrochloric acid was added, and the mixture was stirred at room temperature for 1 hour. The solid obtained by filtration was washed twice with 200 mL of 1 M hydrochloric acid, twice with 200 mL of ion-exchanged water, and twice with 100 mL of DMF in that order, and then twice with 100 mL of ion-exchanged water. and Drying under reduced pressure gave 0.78 g (yield 63%) of a yellow solid. This yellow solid was a high molecular weight redox compound (a high molecular weight redox compound having a quinone group in the molecule). The weight average molecular weight of the obtained high molecular weight redox compound, measured by the same method as in Example 1, was 140,000.

[0142] An acidic gas separation device was produced in the same manner as in Example 1, except that the obtained high molecular weight redox compound (a high molecular weight redox compound having a quinone group in the molecule) was used. The electrolyte layer contained in this acidic gas separation device had a thickness of 50 μm. The thickness of the support contained in the electrolyte layer was 25 μm. The difference obtained by subtracting the thickness of the support from the thickness of the electrolyte layer was 25 μm, and the ratio of the thickness of the support to the thickness of the electrolyte layer (thickness of the support / thickness of the electrolyte layer) was 0.5. Then, using the obtained acidic gas separation device, the same evaluation as in Example 1 was performed. The results are shown in Table 1.

[0143] [Example 5] As a polymerization initiator, 11 mg (0.067 mmol) of 2,2'-azobis-2,4-dimethylvaleronitrile was used, and the polymerization solution was reacted for 24 hours instead of 6 hours. Otherwise, a high molecular weight redox compound was prepared in the same manner as in Example 1. When the weight average molecular weight of the obtained high molecular weight redox compound was measured by the same method as in Example 1, it was 1,490,000. Also, when the radicalization rate of the high molecular weight redox compound was measured by the same method as in Example 1, it was 93% by mass.

[0144] An acidic gas separation device was produced in the same manner as in Example 1, except that the obtained high molecular weight redox compound (a high molecular weight redox compound with a radicalization rate of 90% or more) was used. The electrolyte layer contained in this acidic gas separation device had a thickness of 50 μm. The thickness of the support contained in the electrolyte layer was 25 μm. The difference obtained by subtracting the thickness of the support from the thickness of the electrolyte layer was 25 μm, and the ratio of the thickness of the support to the thickness of the electrolyte layer (thickness of the support / thickness of the electrolyte layer) was 0.5. Then, using the obtained acidic gas separation device, the same evaluation as in Example 1 was performed. The results are shown in Table 1.

[0145] [Example 6] A high molecular weight redox compound was prepared in the same manner as in Example 1, except that 99 mg (0.50 mmol) of ethylene glycol dimethacrylate was used in addition to 22.5 g (100 mmol) of 2,2,6,6-tetramethyl-4-piperidinyl methacrylate. When the radicalization rate of the obtained high molecular weight redox compound was measured by the same method as in Example 1, it was 93% by mass.

[0146] An acidic gas separation device was produced in the same manner as in Example 1, except that the obtained high molecular weight redox compound (a high molecular weight redox compound with a radicalization rate of 90% or more) was pulverized in a mortar and then passed through a sieve with an opening of 20 μm. The electrolyte layer contained in this acidic gas separation device had a thickness of 50 μm. The thickness of the support contained in the electrolyte layer was 25 μm. The difference obtained by subtracting the thickness of the support from the thickness of the electrolyte layer was 25 μm, and the ratio of the thickness of the support to the thickness of the electrolyte layer (thickness of the support / thickness of the electrolyte layer) was 0.5. Then, using the obtained acidic gas separation device, the same evaluation as in Example 1 was performed. The results are shown in Table 1. The obtained high molecular weight redox compound was insoluble in tetrahydrofuran, so the weight average molecular weight could not be measured.

[0147] [Example 7] In Example 1, a liquid film was formed on a support fixed on a glass plate with a coating thickness (coating thickness from the glass plate) of 300 μm manufacture and dried under reduced pressure at 60°C for 8 hours. The dried film obtained by this drying was peeled off from the glass plate. By doing so, a dried film with a support having a thickness of 25 μm was obtained as the electrolyte layer. An acidic gas separation device was produced in the same manner as in Example 1, except for using the electrolyte film thus obtained. The thickness of the support contained in this electrolyte layer was 25 μm. The difference obtained by subtracting the thickness of the support from the thickness of the electrolyte layer was 0 μm, and the ratio of the thickness of the support to the thickness of the electrolyte layer was 1. Then, using the obtained acidic gas separation device, the same evaluation as in Example 1 was performed. The results are shown in Table 1.

[0148] [Example 8] (Production of Support B manufacture ) 75% by weight of 1.2 dtex × 3 mm polyvinyl alcohol fibers (manufactured by Kuraray Co., Ltd., Vinylon, VPB103×3) and 25% by weight of 1.1 dtex × 3 mm polyvinyl alcohol binder fibers (manufactured by Kuraray Co., Ltd., Vinylon binder: VPB105-1×3) were dispersed in water to produce a slurry. Using this slurry, paper was made by a paper-making machine and dried with a Yankee dryer to obtain a base material (support B) with a basis weight of 38.0 g / m 2 , and a thickness of 220 μm.

[0149] In Example 1, the support A was changed to support B, and on the support (support B) fixed on a glass plate, a liquid film was formed with a coating thickness (coating thickness from the surface of the support on the glass plate) of 220 μm manufacture , and dried under reduced pressure at 60°C for 1 hour. This operation was repeated 4 times, and finally dried under reduced pressure at 60°C for 8 hours, and the dried film obtained by the drying was peeled off from the glass plate. By doing so, a dried film with a support having a thickness of 220 μm was obtained as an electrolyte layer. An acid gas separation device was manufactured in the same manner as in Example 1 except for using the electrolyte membrane thus obtained. The thickness of the support contained in this electrolyte layer was 220 μm. The difference obtained by subtracting the thickness of the support from the thickness of the electrolyte layer was 0 μm, and the ratio of the thickness of the support to the thickness of the electrolyte layer was 1. Then, using the obtained acid gas separation device, the same evaluation as in Example 1 was performed. The results are shown in Table 1.

[0150] [Example 9] (Preparation of support C manufacture ) 75% by weight of 1.2 dtex × 3 mm polyvinyl alcohol fibers (manufactured by Kuraray Co., Ltd., Vinylon, VPB103×3) and 25% by weight of 1.1 dtex × 3 mm polyvinyl alcohol binder fibers (manufactured by Kuraray Co., Ltd., Vinylon binder: VPB105-1×3) were dispersed in water to produce a slurry. Using this slurry, paper was made by a paper-making machine and dried with a Yankee dryer to obtain a base material (support C) with a basis weight of 78.0 g / m 2 , and a thickness of 450 μm.

[0151] In Example 1, the support A was changed to support C, and a liquid film was formed on the support (support C) fixed on the glass plate with a coating thickness (coating thickness from the surface of the support on the glass plate) of 220 μm. manufacture Then, it was dried under reduced pressure at 60 °C for 1 hour. This operation was repeated 4 times, and finally, it was dried under reduced pressure at 60 °C for 8 hours, and the dried film obtained by the drying was peeled off from the glass plate. By doing so, a dried film with a support having a thickness of 510 μm was obtained as the electrolyte layer. Except for using the thus obtained electrolyte membrane, an acidic gas separation device was manufactured in the same manner as in Example 1. The thickness of the support contained in this electrolyte layer was 450 μm. The difference obtained by subtracting the thickness of the support from the thickness of the electrolyte layer was 60 μm, and the ratio of the thickness of the support to the thickness of the electrolyte layer was about 0.9 (= 450 / 510). Then, using the obtained acidic gas separation device, the same evaluation as in Example 1 was performed. The results are shown in Table 1.

[0152] [Example 1 0 A high molecular weight redox compound was prepared in the same manner as in Example 1, except that 55 milligrams (0.67 millimoles) of 2,2'-azobis-2,4-dimethylvaleronitrile was used as the polymerization initiator, and the polymerization solution was reacted for 12 hours instead of 6 hours. When the weight average molecular weight of the obtained high molecular weight redox compound was measured by the same method as in Example 1, it was 310,000. Also, when the radicalization rate of the high molecular weight redox compound was measured by the same method as in Example 1, it was 97%.

[0153] Using the obtained high molecular weight redox compound (a high molecular weight redox compound with a radicalization rate of 90% or more), an acidic gas separation device was manufactured in the same manner as in Example 1, except that no support was used. The thickness of the electrolyte membrane was 24 μm. Then, using the obtained acidic gas separation device, the same evaluation as in Example 1 was performed. The results are shown in Table 1.

[0154] [Comparative Example 1] Polymer quantity ​An acidic gas separation device was produced in the same manner as in Example 1, except that 2,2,6,6-tetramethyl-4-piperidinyl methacrylate was used instead of the redox compound. Then, using the obtained acidic gas separation device, the same evaluation as in Example 1 was carried out. The results are shown in Table 1.

[0155] [Comparative Example 2] polymer quantity An acidic gas separation device was produced in the same manner as in Example 1, except that bis(2,2,6,6-tetramethyl-4-piperidyl) adipate was used instead of the redox compound. Then, using the obtained acidic gas separation device, the same evaluation as in Example 1 was carried out. The results are shown in Table 1.

[0156] [Comparative Example 3] In Example 1, a high molecular weight redox compound was prepared in the same manner as in Example 1, except that the amount of hydrogen peroxide used was 20 g. The weight average molecular weight of the obtained high molecular weight redox compound was measured by the same method as in Example 1 and was found to be 79,000. The radicalization rate of the obtained high molecular weight redox compound was measured by the same method as in Example 1 and was found to be 78 mass%. The same procedure as in Example 1 was carried out.

[0157] An acidic gas separation device was produced in the same manner as in Example 1, except that the obtained high molecular weight redox compound (a high molecular weight redox compound with a radicalization rate of less than 90%) was used. Then, using the obtained acidic gas separation device, the same evaluation as in Example 1 was carried out. The results are shown in Table 1.

[0158] [Comparative Example 4] In Example 1, a high molecular weight redox compound was prepared in the same manner as in Example 1, except that the amount of hydrogen peroxide used was 22.5 g. The weight average molecular weight of the obtained high molecular weight redox compound was measured by the same method as in Example 1 and was found to be 79,000. The radicalization rate of the obtained high molecular weight redox compound was measured by the same method as in Example 1 and was found to be 89 mass%. The same procedure as in Example 1 was carried out.

[0159] An acidic gas separation device was produced in the same manner as in Example 1, except that the obtained high molecular weight redox compound (a high molecular weight redox compound with a radicalization rate of less than 90%) was used. Then, using the obtained acidic gas separation device, the same evaluation as in Example 1 was performed. The results are shown in Table 1.

[0160] In Table 1, "-" in the column of weight average molecular weight indicates that the weight average molecular weight could not be measured because the redox compound was insoluble in tetrahydrofuran. Also, "-" in the column of radicalization rate indicates that the radicalization rate could not be measured.

[0161]

Table 1

[0162] As can be seen from Table 1, an acid gas separation device (Examples 1 to 10) in which an electrolyte layer containing a high molecular weight redox compound that adsorbs an acid gas by being electrochemically reduced and desorbs the adsorbed acid gas by being electrochemically oxidized is sandwiched between a pair of electrodes was able to separate the acid gas more from the gas containing the acid gas even when the separation was repeated, as compared with the case where a low molecular weight redox compound was used (Comparative Examples 1 and 2). Also, the acid gas separation devices according to Examples 1 to 3 and 5 to 10 use a high molecular weight redox compound with a radicalization rate of 90% or more, but even when compared with the case where a high molecular weight redox compound with a radicalization rate of less than 90% was used (Comparative Example 3), and even when compared with the case where a high molecular weight redox compound with a radicalization rate slightly less than 90% was used (Comparative Example 4), the acid gas could be separated more from the gas containing the acid gas even when the separation was repeated. Further, the acid gas separation device according to Example 5 had a lower initial separation efficiency as the molecular weight of the high molecular weight redox compound used increased, but compared with the case where a high molecular weight redox compound with a radicalization rate of less than 90% was used (Comparative Examples 3 and 4), the initial separation was good, and even when the separation was repeated, the acid gas could be separated from the gas containing the acid gas to the same extent as in Comparative Examples 3 and 4. Also, the acid gas separation device according to Example 4 uses a high molecular weight redox compound having a quinone group in the molecule, but compared with the case where a high molecular weight redox compound with a radicalization rate of less than 90% was used (Comparative Examples 3 and 4), the initial separation was good, and even when the separation was repeated, the acid gas could be separated more from the gas containing the acid gas.

[0163] In Example 1, an acid gas separation device was made without using a support. manufactureWhen attempting to do so, a suitable electrolyte layer may not be obtained. Specifically, in Example 1, without using a support, a liquid film with a thickness of 200 μm was formed on a glass plate using an applicator, dried under reduced pressure at 60° C. for 8 hours, and the dried film obtained by the drying was peeled off from the glass plate. By doing so, a dried film with a thickness of 15 μm was obtained as the electrolyte layer. On the other hand, the electrolyte layer sometimes broke when peeled off from the glass plate. For this reason, in some cases, it was not possible to fabricate an acid gas separation device. From this, although it is possible to fabricate an acid gas separation device without a support (even in this case, it may be possible to fabricate one, and for example, Example 10 etc. can also be cited), from the perspective of the mechanical strength etc. of the electrolyte layer, it was found that it is preferable for the electrolyte layer to include a support. In addition, when it was possible to fabricate an acid gas separation device, the obtained acid gas separation device was able to suitably separate acid gas from a gas containing acid gas. manufacture In some cases, it was not possible to proceed to fabricate it. From this, although it is possible to fabricate an acid gas separation device without a support manufacture in some cases (even in this case, it may be possible to fabricate one, and for example, Example 10 etc. can also be cited), from the perspective of the mechanical strength etc. of the electrolyte layer, it was found that it is preferable for the electrolyte layer to include a support. manufacture in some cases (even in this case, it may be possible to fabricate one, and for example, Example 10 etc. can also be cited), from the perspective of the mechanical strength etc. of the electrolyte layer, it was found that it is preferable for the electrolyte layer to include a support. manufacture It should be noted that some of the terms like "rae", "trae", "sub - minute" seem rather unusual or potentially misspelled in the original text, which may affect the overall comprehensibility of the translated content. If it was possible to fabricate an acid gas separation device, the obtained acid gas separation device was able to suitably separate acid gas from a gas containing acid gas.

[0164] This application is based on Japanese Patent Application No. 2020-123383 filed on July 20, 2020, and its content is incorporated herein.

[0165] In order to describe the present invention, the present invention has been appropriately and sufficiently described through the embodiments above, but those skilled in the art should recognize that it is easily possible to change and / or improve the above-described embodiments. Therefore, as long as the modified forms or improved forms implemented by those skilled in the art do not depart from the scope of the claims described in the claims, such modified forms or such improved forms are construed to be included within the scope of the rights of the claims.

Industrial Applicability

[0166] According to the present invention, there is provided an acidic gas separation device capable of easily separating an acidic gas from a gas containing the acidic gas and repeating this separation over a long period of time. Further, according to the present invention, there are provided an air purifier, an air conditioner, and an acidic gas concentrator provided with the acidic gas separation device.

Claims

1. An electrolyte layer, A pair of electrodes provided with the electrolyte layer interposed therebetween, A voltage application unit for applying a voltage between the pair of electrodes, and The pair of electrodes are each an electrode capable of permeating gas, The electrolyte layer includes at least one selected from the group consisting of a high molecular weight redox compound having a radicalization rate of 90% or more, a high molecular weight redox compound having a quinone group in the molecule, and a high molecular weight redox compound having an imino group in the molecule, a non-volatile electrolytic solution, and a support, The weight average molecular weight of the high molecular weight redox compound is 2,100 or more and 310,000 or less, An acidic gas separation device, characterized in that the ratio of the thickness of the support to the thickness of the electrolyte layer is 0.3 or more and 1 or less.

2. The pair of electrodes consists of a first electrode on the side that takes in acidic gas from a gas containing acidic gas and a second electrode on the side that releases acidic gas from the electrolyte layer, The acidic gas separation device according to claim 1, wherein the voltage application unit applies a voltage between the pair of electrodes so that the potential of the first electrode is lower than the potential of the second electrode.

3. The acidic gas separation device according to claim 1 or claim 2, wherein the thickness of the electrolyte layer is 1 μm or more and 1,000 μm or less.

4. The acidic gas separation device according to any one of claims 1 to 3, wherein the thickness of the support is 1 μm or more and 1,000 μm or less.

5. The acidic gas separation device according to any one of claims 1 to 4, wherein the difference obtained by subtracting the thickness of the support from the thickness of the electrolyte layer is 0 μm or more and 500 μm or less.

6. The acidic gas separation device according to claim 5, wherein the difference obtained by subtracting the thickness of the support from the thickness of the electrolyte layer is 1 μm or more and 500 μm or less.

7. The acidic gas separation device according to any one of claims 1 to 6, wherein the ratio of the thickness of the support to the thickness of the electrolyte layer is 0.3 or more and 0.99 or less.

8. The basis weight of the support is 1 g / m ２ or more and 50 g / m ２ or less. The acid gas separation device according to any one of claims 1 to 7.

9. The acidic gas separation device according to any one of claims 1 to 8, wherein the support is a non-woven fabric.

10. The acidic gas separation device according to claim 9, wherein the fibers constituting the nonwoven fabric contain at least one selected from the group consisting of polyolefin fibers, cellulose fibers, (meth)acrylic fibers, polyvinyl alcohol fibers, polyvinyl chloride fibers, polystyrene fibers, polyester fibers, polyamide fibers, polycarbonate fibers, and polyurethane fibers.

11. The acidic gas separation device according to any one of claims 1 to 10, wherein the high molecular weight redox compound having a radicalization rate of 90% or more has a repeating unit represented by the following formula (1) in the molecule. 【Chemical 1】 [In formula (1), R １ represents a hydrogen atom or a methyl group.]

12. An air purifier provided with the acidic gas separation device according to any one of claims 1 to 11.

13. An air conditioner provided with the acidic gas separation device according to any one of claims 1 to 11.

14. An acidic gas concentrator provided with the acidic gas separation device according to any one of claims 1 to 11.

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