Adsorbent for polar molecules, concentration method and recovery method for polar molecules, and indicator

Abstract

A molecular adsorbent according to the present invention adsorbs polar molecules and contains, as an active ingredient, an ion exchanger having: an ion exchange resin comprising ion exchange groups that are strongly acidic groups; and a metal ion complex or metal ions ion-exchanged by the ion exchange groups. The polar molecules include nitrogen atoms that have unshared electron pairs. The metal ions are one or more species of trivalent or higher metal ions from among Co2+, Cu2+, Ni2+, Mn2+, V2+, Cs+, Rb+, and K+.

Description

Adsorbent for polar molecules, method for concentrating and recovering polar molecules, and indicator

[0001] The present application relates to a molecular adsorbent that adsorbs polar molecules present in a gas or liquid, a method for concentrating polar molecules using the active ingredient of this molecular adsorbent, and an indicator for determining the adsorption of ammonia and / or amines.

[0002] Molecules such as ammonia and nitrogen dioxide contained in gases, as well as molecules such as ammonia and urea contained in solutions, are harmful. Therefore, these molecules are detoxified by combustion, biodegradation, adsorption with adsorbents, and other methods. Among these detoxification processes, adsorption with adsorbents involves using an adsorbent that highly selectively adsorbs harmful molecules to recover them, and then desorbing and concentrating them, allowing the harmful molecules to be used as a resource. For example, in a liquid containing toluene, a hydrophobic molecule, and water molecules, the toluene can be reused as a resource by adsorbing the toluene onto activated carbon and then desorbing it.

[0003] On the other hand, polar molecules containing nitrogen atoms with unshared electron pairs, such as ammonia and urea, are difficult to separate from water molecules containing oxygen atoms with similar unshared electron pairs. For this reason, it has been difficult to develop an adsorbent that selectively adsorbs polar molecules in water and in gases where water vapor coexists. In addition, for reuse as resources, it is desirable to recover them in the form of single molecules or an aqueous solution. For example, if ammonia and urea can be recovered as a highly concentrated aqueous solution, the recovered ammonia and urea can be used to remove NOx from fertilizers or exhaust gases. ｘ It can be used as a reagent to remove

[0004] By neutralizing the ion exchanger containing protons, polar molecules containing nitrogen atoms with unshared electron pairs, such as ammonia and trimethylamine, can be selectively adsorbed onto the ion exchanger. However, a large amount of energy is required to separate the basic molecules adsorbed on the ion exchanger from the protons. In addition, zinc ions (Zn ２＋ A technique is known in which ammonia is adsorbed onto an ion exchange resin incorporating ammonium ions, and then the ammonia is desorbed as ammonium ions using an acid (Patent Documents 1 to 3).

[0005] In these techniques, the molecules are recovered as salts such as sulfates rather than as solutions, making it difficult to isolate the molecules. In order to reuse the recovered polar molecules as resources, it is desirable to desorb the molecules without using chemicals such as acids. In Patent Document 1, zinc ions are supported on an ion exchange resin, ammonia is adsorbed, and the resin is then washed with a solution containing sulfuric acid and zinc sulfate, recovering the adsorbed ammonia as an aqueous ammonium zinc sulfate solution. However, separating zinc sulfate and ammonia from the liquid recovered as an aqueous ammonium zinc sulfate solution requires reagents and a large amount of energy, which increases costs.

[0006] Similarly, in Patent Documents 2 and 3, an acid such as sulfuric acid is used to desorb ammonia adsorbed on an ion exchange resin. This ammonia is recovered as ammonium ions by reaction with the acid. The ammonia recovered as ammonium ions cannot be reused as ammonia unless it is separated from the acid by ammonia stripping or the like. For this reason, in practice, it is desirable to recover the polar molecules as a simple substance or an aqueous solution using water and air, rather than using an acid, to desorb the polar molecules adsorbed on the ion exchange resin. There is no particular problem with heating during desorption, as long as the temperature is within a range in which polar molecules such as ammonia do not burn or thermally decompose.

[0007] In addition, Ni introduced into the ion exchanger having a carboxyl group ２＋ It is known that ammonia coordinates with metal ions such as those mentioned above (Non-Patent Document 1). However, Non-Patent Document 1 does not mention the influence of functional groups responsible for ion exchange on molecular adsorption, the amount of ammonia adsorbed, or whether ammonia can be recovered. Furthermore, when a polar molecule containing a nitrogen atom with an unshared electron pair is analyzed using a conventional ion exchanger, if the polar molecule is ammonia, it can cause foul odors and water pollution, so a simple analysis method is needed.

[0008] Known analytical methods for ammonia include ion chromatography, which converts ammonia to ammonium ions in an acidic range, and the indophenol method. However, ion chromatography requires large equipment, and the indophenol method is cumbersome to operate. Passive indicators and gas detector tubes, which change color depending on the ammonia concentration, are known as simple methods for detecting ammonia in gaseous solutions. However, these rely on a color change due to an irreversible reaction, necessitating time and reaction volume management. To enable simple monitoring of ammonia and / or amine concentrations, the development of an ammonia and / or amine indicator that adsorbs ammonia and / or amine at any concentration and changes color using a reversible desorbable reaction, is desirable.

[0009] JP 2002-501427 A U.S. Pat. No. 4,263,145 U.S. Pat. No. 4,695,387

[0010] Ligand Exchange. I. Equilibria, F. Hefferich Journal of American Chemical Society,1962, 84, P 3237-3242

[0011] The present application has been made in light of the above circumstances, and aims to provide an adsorbent that can recover polar molecules such as ammonia containing a nitrogen atom with an unshared electron pair as a substance containing the adsorbed polar molecules. Another aim is to provide a method for concentrating polar molecules containing a nitrogen atom with an unshared electron pair using the active ingredient of the adsorbent. A further aim is to provide an indicator for ammonia and / or amines that changes color by utilizing a reversible, eliminative reaction.

[0012] It is generally known that the selectivity of metal ions adsorbed to ion exchange groups varies depending on whether the ion exchange groups in an ion exchange resin are strongly acidic sulfonic acid groups or weakly acidic carboxyl groups. However, it was not known that the adsorption capacity of polar molecules containing a nitrogen atom with an unshared electron pair of the metal ion exchanged with the ion exchange group differs depending on the ion exchange group. The present inventors ion-exchanged metal ions with the ion exchange groups of various ion exchange resins and evaluated their adsorption capacity for polar molecules. As a result, they found that metal ions exchanged with strongly acidic sulfonic acid groups are effective for adsorbing polar molecules.

[0013] The molecular adsorbent according to one aspect of the present invention uses an ion exchanger containing an ion exchange resin having ion exchange groups that are strongly acidic groups and a metal ion or a metal ion complex that has been ion-exchanged by the ion exchange groups as an active ingredient, and adsorbs polar molecules. The polar molecule contains a nitrogen atom with an unshared electron pair. The metal ion is a trivalent or higher metal ion, Co ２＋ , Cu ２＋ , Ni ２＋ , Mn ２＋ , V ２＋ , Cs ＋ , Rb ＋ , and K ＋ It is one or more of the following.

[0014] The indicator for ammonia and / or amines according to one aspect of the present invention uses an ion exchanger containing an ion exchange resin having ion exchange groups that are strongly acidic groups and a metal ion or a metal ion complex that has been ion-exchanged by the ion exchange groups as an active ingredient, and can determine the adsorption of ammonia and / or amines to the ion exchanger by a color change. ２＋ , Ni ２＋ , Cu ２＋ , Fe ３＋ , or Mn ２＋ is.

[0015] The method for concentrating polar molecules according to one aspect of the present invention includes: an ion exchange resin having ion exchange groups that are strongly acidic groups; and a trivalent or higher metal ion, Co, which is ion-exchanged by the ion exchange groups. ２＋ , Cu２＋ , Ni ２＋ , Mn ２＋ , V ２＋ , Zn ２＋ , Cs ＋ , Rb ＋ , and K ＋ and a condensation step of heating the ion exchanger to which the polar molecules have been adsorbed and condensing the gas generated from the ion exchanger.

[0016] The molecular adsorbent of the present application allows for the recovery of polar molecules containing adsorbed nitrogen atoms with unshared electron pairs through simple operations such as heating. The method for concentrating polar molecules of the present application involves adsorbing polar molecules containing nitrogen atoms with unshared electron pairs onto a specific ion exchanger, then heating the ion exchanger to condense the resulting gas, thereby concentrating the polar molecules. Furthermore, the indicator for ammonia and / or amines of the present application allows for the determination of ammonia and / or amine adsorption by a color change.

[0017] Graph showing the relationship between the ion exchanger of Example 1 and the amount of urea adsorption. Graph showing the relationship between the ion exchanger of Example 2 and the amount of urea adsorption. Graph showing the relationship between the ion exchanger or ion exchange resin of Example 5 and the amount of ammonia adsorption. Graph showing the relationship between the ion exchanger of Example 6 and the amount of ammonia acid desorption. ２＋ Graph showing the change in the amount of ammonia desorbed when ammonia adsorption and desorption were repeated on a strongly acidic ion exchanger having the Ti ４＋ Graph showing the change in the amount of urea desorbed when urea adsorption and desorption were repeated on a strongly acidic ion exchanger having Ti ４＋ 10 is a graph showing the cumulative amount of urea adsorbed when urea was adsorbed again after 30 cycles of urea adsorption and desorption were repeated on a strongly acidic ion exchanger having Ti ４＋11 is a graph showing the cumulative desorption amount when urea re-adsorbed is desorbed after 30 cycles of adsorption and desorption of urea on a strongly acidic ion exchanger having a metal ion. 12 is a schematic diagram showing the recovery of urea from an adsorbent made of a strongly acidic ion exchanger containing a metal ion in Example 11. 13 is an image showing a glass container from which solid urea was recovered in Example 11. 14 is a graph showing the adsorption amount of trimethylamine in an aqueous solution in Example 12. 15 is a graph showing the adsorption amount of butylamine in an aqueous solution in Example 13.

[0018] The molecular adsorbent of one embodiment of the present application contains a specific ion exchanger (hereinafter, sometimes referred to as the "ion exchanger of this embodiment") as an active ingredient. The molecular adsorbent of this embodiment adsorbs polar molecules containing a nitrogen atom with an unshared electron pair (hereinafter, sometimes referred to as the "specific polar molecule"). There are no particular restrictions on the specific polar molecule as long as it can coordinate to the metal of the ion exchanger of this embodiment. Examples of such specific polar molecules include ammonia in which a nitrogen atom coordinates to a metal, nitrogen oxides in which an oxygen atom coordinates to a metal, organic compounds such as urea having a keto group, and organic compounds having an amino group or an amide group.

[0019] Among these, the predetermined polar molecule is preferably at least one of ammonia, amine, and urea, which are highly valuable for reuse, and may be, for example, ammonia, amine, or urea. Furthermore, there are no particular limitations on the form of the predetermined polar molecule, as long as it can come into contact with the molecular adsorbent. That is, the predetermined polar molecule may be contained in a gas or in a liquid such as water or an organic medium, for example, dissolved in water or an organic solvent.

[0020] The polar amine molecules adsorbed by the molecular adsorbent of this embodiment may be, for example, at least one of trimethylamine and butylamine, or may be other amines other than monomethylamine and dimethylamine (i.e., adsorbing amines other than monomethylamine and dimethylamine). In other words, the molecular adsorbent of this embodiment may be a molecular adsorbent for adsorbing the above-mentioned polar molecules. The present invention can also provide an adsorbent containing the molecular adsorbent of this embodiment.

[0021] The ion exchanger of this embodiment comprises an ion exchange resin and a metal ion or a complex of this metal ion. The ion exchange resin comprises an ion exchange group, which is a strongly acidic group. The type of ion exchange resin is not particularly limited as long as it has a strongly acidic group, and for example, a commercially available ion exchange resin can be used. An example of the strongly acidic group is a sulfonic acid group. The metal ion or the complex of this metal ion is ion-exchanged with the ion exchange group, more specifically, with a cation such as an H ion or Na ion of the ion exchange group. In other words, the metal ion or the complex of this metal ion is bonded to the ion exchange group. The metal ion may be a trivalent or higher metal ion, Co ２＋ , Cu ２＋ , Ni ２＋ , Mn ２＋ , V ２＋ , Cs ＋ , Rb ＋ , and K ＋ and trivalent or higher metal ions, Co ２＋ , Ni ２＋ , Mn ２＋ , V ２＋ , Cs ＋ , Rb ＋ , and K ＋ The metal ions of the ion exchanger may be one or more of the above. Copper ions may be excluded from the metal ions of the ion exchanger (in other words, metal ions other than copper ions may be bonded to the above ion exchange groups).

[0022] Trivalent or higher metal ions include Fe ３＋ , Cr ３＋ , Al ３＋ , Ti ３＋ , In ３＋ , Ru ３＋ , Ti ４＋ , Zr ４＋ , Sn ４＋ and Hf ４＋ The metal ion may be Fe. ３＋ , Ti ３＋ , Ru ３＋ , Zr ４＋ , Hf ４＋ , Sn ４＋ and Cs ＋When the metal ions are one or more of the above, the amount of urea that can be adsorbed by the molecular adsorbent of this embodiment is large. Therefore, when the molecular adsorbent of this embodiment is used as a urea adsorbent, it is preferable that the metal ions are these metal ions. In addition, when the metal ions are Ni ２＋ and / or Cu ２＋ When the molecular adsorbent of the present embodiment is used as an ammonia adsorbent, the amount of ammonia that can be adsorbed by the molecular adsorbent of the present embodiment is large. ２＋ and Cu ２＋ It is preferable that the metal ion is at least one of the above.

[0023] Also, when the polar molecule is an amine (e.g., trimethylamine and / or butylamine), the metal ion is Co ２＋ , Ni ２＋ , Cu ２＋ , Mn ２＋ and Fe ３＋ and Co ２＋ , Ni ２＋ , Mn ２＋ and Fe ３＋ It may be one or more selected from the group consisting of:

[0024] In the molecular adsorbent of this embodiment, Zn ２＋ is not ion-exchanged with the ion-exchange group. ２＋ is an ion that is toxic to living organisms depending on its concentration. ２＋ The Water Pollution Control Act sets strict discharge standards of less than 2 mg / L for trivalent or higher metal ions, Co ２＋ , Cu ２＋ , Ni ２＋ , Mn ２＋ , V ２＋ , Cs ＋ , Rb ＋ , Sn ４＋ and K. ＋ is Zn ２＋ The general wastewater standard concentration standard value is higher than that of Zn, or these metals are not regulated by the Water Pollution Control Law. ２＋Since the molecular adsorbent of this embodiment has lower toxicity than the ion exchanger of this embodiment, safety is improved when using the molecular adsorbent of this embodiment. The larger the substance amount (so-called molar amount) of the metal ion contained in the ion exchanger of this embodiment, the larger the amount of polar molecules adsorbed. The metal ion concentration of the ion exchanger (substance amount of metal ion / mass of ion exchanger) is preferably 0.05 mmol / g or more, more preferably 0.2 mmol / g or more, and particularly preferably 0.5 mmol / g or more.

[0025] The form of the metal ion ion exchanged in the ion exchanger may be not only the metal ion but also a metal ion complex, even if it is coordinated with hydrated water or a chelate, as long as it does not inhibit the adsorption of a specific polar molecule to the ion exchanger. For example, the form of the metal ion ion exchanged in the ion exchanger may be an ammine complex in which ammonia is coordinated to the metal ion. In addition to the ion exchanger, the molecular adsorbent of this embodiment may also contain a thickener, a binder, or a substrate that ensures the strength of the molecular adsorbent itself.

[0026] In one embodiment, the present invention can provide an adsorption method for adsorbing polar molecules using the molecular adsorbent described above. In this embodiment, the polar molecules are as described above.

[0027] In one embodiment, the present invention can also provide use of the molecular adsorbent described above for adsorption (or recovery) of the polar molecules described above.

[0028] Furthermore, the present inventors have found that when ammonia or an amine is adsorbed onto some of the ion exchangers of this embodiment, the adsorption of ammonia or an amine onto the ion exchanger can be determined by the color change of the ion exchanger. It is believed that in these ion exchangers, the amino group of the amine coordinates with the metal ion contained in the ion exchanger. Ion exchangers containing metal ions that have electrons in their d orbitals but whose d orbitals are not completely filled generally exhibit a visible color because the energy difference when an electron in the d orbital transitions to an empty d orbital generally corresponds to the energy of visible light.

[0029] It is speculated that the color change of these ion exchangers occurs when the amino group coordinates with the metal ion, due to a change in the energy level of the d orbital. This speculation is supported by the fact that ion exchangers containing sodium ions that do not have electrons in the d orbital did not change color upon adsorption of ammonia. Therefore, it is thought that amines in general that contain amino groups, in addition to ammonia, would also change color when adsorbed onto these ion exchangers. The ammonia and / or amine indicator of the present embodiment contains, as its active ingredient, an ion exchanger that includes an ion exchange resin with a strongly acidic ion exchange group and a metal ion or a metal ion complex that has been ion-exchanged via the ion exchange group.

[0030] In the indicator for ammonia and / or amines of this embodiment, the adsorption of ammonia and / or amines to the ion exchanger (presence or absence of adsorption and the amount of adsorption) is determined by the color change of the ion exchanger. Therefore, the indicator of this embodiment may be an indicator for determining the presence or absence and amount of ammonia, or an indicator for determining the presence or absence and amount of amines. ２＋ , Ni ２＋ , Cu ２＋ , Fe ３＋ , or Mn ２＋ and Co ２＋ , Ni ２＋ , Fe ３＋ , or Mn ２＋ The color change also increases as the amount of ammonia and / or amine adsorbed onto the ion exchanger increases. Therefore, the ammonia and / or amine indicator of this embodiment allows for quantitative evaluation of the amount of ammonia and / or amine adsorbed. The amine may be, for example, at least one of trimethylamine, butylamine, diethylamine, and monoethanolamine, or at least one of trimethylamine and butylamine, or an amine other than monomethylamine and dimethylamine.

[0031] The specific color change of the ion exchanger when polar molecules are adsorbed varies depending on the types of metal ions and ammonia and / or amines, but examples of the color change include the following: ２＋ : Reddish brown to blackish brown Ni ２＋ : Yellow-green to blue or green Cu ２＋ : Green to bluish purple or blue Fe ３＋ : Reddish brown to blackish brown Mn ２＋ : Orange (reddish brown) to blackish brown

[0032] Ion exchangers according to embodiments of the molecular adsorbent and ammonia and / or amine indicator can be prepared, for example, as follows: First, an ion exchange resin having ion exchange groups that are strongly acidic groups is prepared. Such ion exchange resins are commercially available. When the cations of the ion exchange groups are H ions, the ion exchange resin is placed in an aqueous NaOH solution and stirred or shaken to convert the cations of the ion exchange groups to Na ions. The cations of the ion exchange resin are converted to Ni ions. ２＋ or Mn ２＋ This is to facilitate exchange with the desired metal ions, such as:

[0033] Next, the Na ions in the ion exchange resin are exchanged with the target metal ions. This is done by placing the ion exchange resin in an aqueous solution of the target metal ions (metal salt aqueous solution) and stirring or shaking the resin. After several washing steps with ultrapure water, the resin is subjected to a dehydration step such as suction filtration and a drying step at a temperature of about 40°C to 60°C, thereby obtaining the ion exchanger of this embodiment.

[0034] The ion exchanger of this embodiment can desorb adsorbed predetermined polar molecules at a high concentration by heating. Note that there are other ion exchangers besides the ion exchanger of this embodiment that can desorb adsorbed predetermined polar molecules at a high concentration by heating.

[0035] A method for concentrating polar molecules according to one embodiment of the present application includes an adsorption step and a condensation step. In the adsorption step, a gas or liquid containing a predetermined polar molecule is brought into contact with the ion exchanger, thereby adsorbing the polar molecule containing a nitrogen atom having an unshared electron pair. As described above, the ion exchanger used in the concentration method according to this embodiment is similar to the ion exchanger according to the embodiment of the molecular adsorbent described above, and includes an ion exchange resin having ion exchange groups that are strong acidic groups, and metal ions or complexes of these metal ions that have been ion-exchanged with the ion exchange groups.

[0036] The metal ions are trivalent or higher metal ions, Co ２＋ , Cu ２＋ , Ni ２＋ , Mn ２＋ , V ２＋ , Zn ２＋ , Cs ＋ , Rb ＋ , and K ＋ The trivalent or higher metal ions are Fe, as described above. ３＋ , Cr ３＋ , Al ３＋ , Ti ３＋ , In ３＋ , Ru ３＋ , Ti ４＋ , Zr ４＋ , Sn ４＋ and Hf ４＋ It may be one or more of the above.

[0037] The polar molecule is preferably at least one of ammonia and urea. Since the adsorption phenomenon is generally an exothermic reaction, the adsorption step is preferably carried out at a low temperature. The temperature at which the adsorption step is carried out is preferably 50°C or less, more preferably 30°C or less, and even more preferably 10°C or less.

[0038] In the condensation step, the ion exchanger to which the polar molecules have been adsorbed is heated to condense the gas generated from the ion exchanger. The condensed liquid contains the polar molecules. The concentration of the polar molecules in this liquid is greater than the concentration of the specified polar molecules in the gas or liquid contacted with the ion exchanger in the adsorption step. In the condensation step, the ion exchanger is preferably heated to a temperature of 60°C or higher but lower than the heat resistance temperature of the ion exchanger. The heating temperature of the ion exchanger is more preferably 80°C or higher, and even more preferably 100°C or higher. This is because the higher the temperature, the greater the amount and speed of the specified polar molecules desorbed.

[0039] In the condensation step, the ion exchanger may be heated while being brought into contact with water vapor. This is because a condensed liquid containing a higher concentration of the predetermined polar molecule is obtained. Furthermore, in the condensation step, the predetermined polar molecule may be desorbed from the ion exchanger by flowing water or a gas around the ion exchanger. In addition to inert gases such as nitrogen, argon, and helium, air containing oxygen may also be used as the gas, as long as it does not decompose the predetermined polar molecule being desorbed.

[0040] In another preferred embodiment, the present invention provides a method for recovering urea (an example of a polar molecule) concentrated by the above-described method for concentrating a polar molecule. In this case, the trivalent or higher metal ion used in the concentration method is Fe. ３＋ , Cr ３＋ , Al ３＋ , Ti ３＋ , In ３＋ , Ru ３＋ , Ti ４＋ , Zr ４＋ , Sn ４＋ , and Hf ４＋ It may be one or more selected from the group consisting of:

[0041] This recovery method includes a step of heating a container containing the ion exchanger (adsorbent) having urea adsorbed thereon and applying negative pressure to the upper part of the container to cause suction, thereby precipitating solid urea. As will be described in detail later in Examples, the ion exchanger having urea adsorbed thereon is placed in a container, and suction is applied from the upper part of the container while heating (in other words, negative pressure is applied), thereby precipitating urea in the upper part of the container and recovering solid urea.

[0042] Preparation Example 1 A strongly acidic ion exchange resin having sulfonic acid groups (Muromachi Chemical Co., Ltd., Muromax XSC-1614-Na (hereinafter referred to as “XSC.Na”)) was placed in a 50 mL centrifuge tube. ＋ ") and 40 mL of a 0.2 mol / L metal salt aqueous solution were placed in the centrifuge tube. The tube was shaken overnight at 25°C and 400 rpm. The tube was then centrifuged at a centrifugal acceleration of 3000 G for 1 minute, the supernatant was discarded, and 10 mL of ultrapure water (Milli-Q water (hereinafter the same)) was added. This process was repeated three times, and the tube was then dehydrated by suction filtration. After dehydration, the tube was dried at 60°C to obtain various ion exchangers, which are ion exchange resins in which Na ions have been exchanged for various metal ions.

[0043] The names of the metal salt aqueous solutions or the metal salts contained in the metal salt aqueous solutions and the ion exchangers obtained from the metal salt aqueous solutions are listed below. Cobalt (II) nitrate hexahydrate: XSC.Co ２＋ Nickel (II) nitrate hexahydrate: XSC.Ni ２＋ Copper (II) sulfate pentahydrate: XSC. Cu ２＋ Iron (III) nitrate nonahydrate: XSC. Fe ３＋ Chromium (III) chloride hexahydrate: XSC.Cr ３＋ Manganese(II) chloride tetrahydrate: XSC.Mn ２＋ Aluminum nitrate nonahydrate: XSC.Al ３＋ Indium(III) chloride tetrahydrate: XSC.In ３＋ Vanadium(II) chloride: XSC.V ２＋ Titanium (III) chloride 20 wt % aqueous solution: XSC.Ti ３＋ Vanadium(III) chloride: XSC.V３＋ Zirconium chloride (IV): XSC.Zr ４＋ Ruthenium (III) chloride n-hydrate: XSC.Ru ３＋ Zinc sulfate (II) heptahydrate: XSC.Zn ２＋ Strontium (II) chloride hexahydrate: XSC.Sr ２＋ Calcium chloride (II): XSC.Ca ２＋ Magnesium(II) chloride hexahydrate: XSC.Mg ２＋ Cesium chloride: XSC.Cs ＋ Rubidium chloride: XSC.Rb ＋ Potassium chloride: XSC.K ＋ Hafnium(IV) chloride: XCS.Hf ４＋

[0044] Preparation Example 2 Various ion exchangers in which Na ions were exchanged for various metal ions were obtained in the same manner as in Preparation Example 1, except that instead of the strongly acidic ion exchange resin in Preparation Example 1, a weakly acidic ion exchange resin having carboxyl groups (Organo Corporation, FPC3500) was used which had been treated with NaOH to exchange H ions for Na ions, and that the metal salts contained in the aqueous metal salt solution were partially different.

[0045] The names of the metal salt aqueous solutions or the metal salts contained in the metal salt aqueous solutions and the ion exchangers obtained from the metal salt aqueous solutions are listed below. Nickel (II) nitrate hexahydrate: FPC3500.Ni ２＋ Iron (III) nitrate nonahydrate: FPC3500. Fe ３＋ Chromium (III) chloride hexahydrate: FPC3500. Cr ３＋ Manganese (II) chloride tetrahydrate: FPC3500.Mn ２＋ Aluminum nitrate nonahydrate: FPC3500.Al ３＋ Titanium (III) chloride 20 wt% aqueous solution: FPC3500.Ti ３＋

[0046] Preparation Example 3 Various ion exchangers in which Na ions were exchanged with various metal ions were obtained in the same manner as in Preparation Example 2, except that instead of the weakly acidic ion exchange resin in Preparation Example 2, a weakly acidic ion exchange resin having carboxyl groups (Organo Corporation, Amberlite IRC-76) was used which had been treated with NaOH to exchange H ions for Na ions.

[0047] The names of the metal salt aqueous solutions or the metal salts contained in the metal salt aqueous solutions and the ion exchangers obtained from the metal salt aqueous solutions are listed below. Nickel (II) nitrate hexahydrate: IRC-76.Ni ２＋ Iron (III) nitrate nonahydrate: irc-76. Fe ３＋ Chromium (III) chloride hexahydrate: IRC-76. Cr ３＋ Manganese (II) chloride tetrahydrate: irc-76.Mn ２＋ Aluminum nitrate nonahydrate: IRC-76.Al ３＋ Titanium (III) chloride 20 wt% aqueous solution: irc-76.Ti ３＋

[0048] Preparation Example 4 Various ion exchangers in which Na ions were exchanged with various metal ions were obtained in the same manner as in Preparation Example 2, except that instead of the weakly acidic ion exchange resin in Preparation Example 2, a strongly acidic ion exchange resin having sulfonic acid groups (Alfa Aesar, Amberlite ir-120) was used which had been treated with NaOH to exchange H ions for Na ions.

[0049] The names of the metal salt aqueous solutions or the metal salts contained in the metal salt aqueous solutions and the ion exchangers obtained from the metal salt aqueous solutions are listed below. Nickel (II) nitrate hexahydrate: ir-120.Ni ２＋ Iron (III) nitrate nonahydrate: ir-120.Fe ３＋ Chromium (III) chloride hexahydrate: ir-120. Cr ３＋ Manganese(II) chloride tetrahydrate: ir-120.Mn ２＋ Aluminum nitrate nonahydrate: ir-120.Al ３＋ Titanium (III) chloride 20 wt% aqueous solution: ir-120.Ti ３＋

[0050] Preparation Example 5 Various ion exchangers in which Na ions were exchanged with various metal ions were obtained in the same manner as in Preparation Example 2, except that instead of the weakly acidic ion exchange resin in Preparation Example 2, a strongly acidic ion exchange resin having sulfonic acid groups (Alfa Aesar, Amberlyst 15) was used which had been treated with NaOH to exchange H ions for Na ions.

[0051] The names of the metal salt aqueous solutions or the metal salts contained in the metal salt aqueous solutions and the ion exchangers obtained from the metal salt aqueous solutions are listed below. Nickel (II) nitrate hexahydrate: A15. Ni ２＋ Iron (III) nitrate nonahydrate: A15. Fe ３＋ Chromium (III) chloride hexahydrate: A15. Cr ３＋ Manganese(II) chloride tetrahydrate: A15. Mn ２＋ Aluminum nitrate nonahydrate: A15. Al ３＋ Titanium (III) chloride 20 wt % aqueous solution: A15. Ti ３＋

[0052] Preparation Example 6 Various ion exchangers in which Na ions were exchanged with various metal ions were obtained in the same manner as in Preparation Example 2, except that instead of the weakly acidic ion exchange resin in Preparation Example 2, a weakly acidic ion exchange resin having carboxyl groups (Mitsubishi Chemical Corporation, Relite WK60L) was used which had been treated with NaOH to exchange H ions for Na ions.

[0053] The names of the metal salt aqueous solutions or the metal salts contained in the metal salt aqueous solutions and the ion exchangers obtained from the metal salt aqueous solutions are listed below. Nickel (II) nitrate hexahydrate: WK60.Ni ２＋ Iron (III) nitrate nonahydrate: WK60. Fe ３＋ Chromium (III) chloride hexahydrate: WK60.Cr ３＋ Manganese(II) chloride tetrahydrate: WK60.Mn ２＋ Aluminum nitrate nonahydrate: WK60.Al ３＋ Titanium (III) chloride 20 wt% aqueous solution: WK60.Ti ３＋

[0054] Preparation Example 7 Various ion exchangers in which Na ions were exchanged with various metal ions were obtained in the same manner as in Preparation Example 2, except that instead of the weakly acidic ion exchange resin in Preparation Example 2, a weakly acidic ion exchange resin having carboxyl groups (Mitsubishi Chemical Corporation, Relite WK100) was used, which had been treated with NaOH to exchange H ions for Na ions.

[0055] The names of the metal salt aqueous solutions or the metal salts contained in the metal salt aqueous solutions and the ion exchangers obtained from the metal salt aqueous solutions are listed below. Nickel (II) nitrate hexahydrate: WK100.Ni ２＋ Iron (III) nitrate nonahydrate: WK100.Fe ３＋ Chromium (III) chloride hexahydrate: WK100.Cr ３＋ Manganese (II) chloride tetrahydrate: WK100.Mn ２＋ Aluminum nitrate nonahydrate: WK100.Al ３＋ Titanium (III) chloride 20 wt% aqueous solution: WK100.Ti ３＋

[0056] Preparation Example 8: In a beaker, 420 g of the same ion exchange resin as in Preparation Example 1 and TiCl containing approximately 6 wt % Ti were added. ３ 700 mL of aqueous solution was added and stirred for 4 hours with a magnetic stirrer. To wash and remove salts in the water, the supernatant was discarded and 700 mL of water was added. This process was repeated six times. The water was filtered to recover the wet ion exchange resin, which was then dried at a temperature of 60°C. The dried ion exchange resin contained Ti. ３＋ It turned purple.

[0057] Ti in ion exchange resin ３＋ Ti ４＋ To oxidize the ion exchange resin, 230 g of the ion exchange resin and 500 mL of ultrapure water were placed in a 5 L beaker and stirred with a mechanical stirrer for 3 hours. After suction filtration and drying at 60°C, Ti ４＋ XSC.Ti is an ion exchange resin with ４＋ XSC.Ti was obtained. ４＋ The ion exchange resin exhibited its natural orange color.

[0058] Preparation Example 9: 100 g of the same ion exchange resin as in Preparation Example 1 and 400 mL of a 0.4 mol / L metal salt aqueous solution were placed in a 1 L container. The container was shaken at room temperature and a rotation speed of 400 rpm for three nights. After shaking, the mixture was filtered under suction and dried at 60°C to obtain various ion exchangers, which were ion exchange resins in which Na ions had been exchanged for various metal ions.

[0059] The names of the metal salt aqueous solutions or the metal salts contained in the metal salt aqueous solutions and the ion exchangers obtained from the metal salt aqueous solutions are listed below. Silver nitrate: gXSC (for gases, same as XSC above). Ag ＋ Chromium (III) chloride hexahydrate: gXSC.Cr ３＋ Manganese(II) chloride tetrahydrate: gXSC.Mn ２＋ Iron (III) nitrate nonahydrate: gXSC. Fe ３＋ Cobalt (II) nitrate hexahydrate: gXSC.Co ２＋ Nickel (II) nitrate hexahydrate: gXSC.Ni ２＋ Copper (II) sulfate pentahydrate: gXSC. Cu ２＋ Zinc sulfate (II) heptahydrate: XSC.Zn ２＋

[0060] Preparation Example 10 Gas pump outlet and gXSC.Ni ２＋ The inlet of a column containing 200 g of 4 wt % ammonia water was connected to the outlet of the column. The outlet of the column was connected to the inlet of a gas phase containing ammonia gas evaporated from the ammonia water at the top of a 20 L tank containing 7 L of 4 wt % ammonia water. The ammonia concentration in the gas phase measured with a gas detector tube was 32,000 ppmv. The outlet of the gas phase at the top of this tank was connected to the inlet of a gas pump. In other words, the ammonia gas at the top of the tank was allowed to circulate through the tank, gas pump, and column. The gas at the top of the tank was circulated overnight using the gas pump at a flow rate of approximately 0.5 L / min, and gXSC.Ni ２＋ Ion exchanger XSC.Ni with ammonia adsorbed on it ２＋ NH ３ obtained.

[0061] Preparation Example 11 Nickel (II) nitrate hexahydrate was dissolved in ultrapure water to prepare a 0.3 mol / L aqueous solution of nickel nitrate. 0.4 L was placed in a 1 L I-Boy flask, and 100 g of Amberlite CT200 Na, a strong acid cation exchange resin with a sulfo group (sulfonic acid group) as a functional group, was added. This was shaken at 180 rpm at room temperature for 71 hours in a Taitec shaker TS-20, and adsorbed. Afterwards, the solid-liquid separation was carried out by suction filtration, followed by washing three times with 0.4 L of ultrapure water, suction filtration, and drying in a dryer at 60 ° C. for 17 hours. 200 CT. Ni ２＋ The change in nickel ions in the solution before and after adsorption was measured by MP-AES, and the amount of nickel ions exchanged, calculated by dividing the amount of nickel ions in the solution by the mass of the ion exchange resin, was 0.68 mmol / g.

[0062] Preparation Example 12: Tin (IV) chloride pentahydrate was dissolved in ultrapure water to prepare a 0.4 mol / L tin chloride aqueous solution. 0.08 L of this solution was placed in a 1 L I-Boy tube, and 100 g of Amberlite CT200 Na, a strong acid cation exchange resin with sulfo groups as functional groups, was added. This was shaken at 180 rpm at room temperature for 71 hours in a Taitec shaker TS-20 for adsorption. The solid-liquid separation was then carried out by suction filtration, followed by washing with ultrapure water and suction filtration. The resulting solution was then dried in a dryer at 60°C for 17 hours to obtain 200 CT. Sn ４＋ obtained.

[0063] Example 1: 2 g of urea was dissolved in 98 g of ultrapure water to obtain a 2 wt% urea solution. 4 mL of this urea solution and 0.4 g of each of the ion exchangers prepared in Preparation Example 1 were placed in a 15 mL centrifuge tube and shaken overnight at 900 rpm to allow urea to adsorb onto the ion exchanger. The tube was then centrifuged at 3,000 rpm for 5 minutes, and the urea concentration in the supernatant was evaluated by HPLC. The amount of urea in the urea solution before and after adsorption onto the ion exchanger was divided by the mass of the ion exchanger to calculate the urea adsorption amount (mmol / g).

[0064] The results are shown in Figure 1. Figure 1 shows the relationship between the ion exchanger and the amount of urea adsorbed. As shown in Figure 1, ３＋ , Ti ３＋ , Zr ４＋ , Ru３＋ , and Hf ４＋ The urea adsorption amount of ion exchangers containing metal ions with high valences, such as Cs, tended to be high. ＋ The urea adsorption capacity of the ion exchanger containing urea was the highest.

[0065] Example 2 In order to investigate whether the urea adsorption amount differs depending on the ion exchange resin (XSC-1614-Na, FPC3500, Amberlite irc-76, Amberlite ir-120, Amberlyst 15, Relite WK60L, and Relite WK100) even when the ion exchangers in Preparation Examples 1 to 7 were exchanged with the same metal ions, Ni ２＋ , Fe ３＋ , Cr ３＋ , Mn ２＋ , Al ３＋ , or Ti ３＋ The urea adsorption capacity of various ion exchangers including

[0066] The results are shown in Figure 2. Figure 2 shows the relationship between the ion exchanger and the urea adsorption capacity. As shown in Figure 2, the urea adsorption capacity of the ion exchangers using strongly acidic ion exchange resins (XSC-1614-Na, Amberlite ir-120, and Amberlyst 15) was higher than the urea adsorption capacity of the ion exchangers using weakly acidic ion exchange resins (FPC3500, Amberlite irc-76, Relite WK60L, and Relite WK100).

[0067] The reason why the urea adsorption amount of the ion exchanger using a weakly acidic ion exchange resin was low is thought to be because urea is difficult to adsorb to the carboxyl groups coordinated with metal ions in the weakly acidic ion exchange resin. In contrast, the urea adsorption amount of the ion exchanger using a strongly acidic ion exchange resin is high. This is thought to be because the sulfonic acid groups contained in the strongly acidic ion exchange resin have weak coordination power for metal ions, and urea is preferentially adsorbed to the sulfonic acid groups over the metal ions. These results demonstrate that ion exchangers using ion exchange resins with strongly acidic groups such as sulfonic acid groups are effective as molecular adsorbents for adsorbing polar molecules such as urea.

[0068] Example 3 XSC.Ti prepared in Preparation Example 8 ４＋ The column was filled with 2 wt% urea water, and the 2 wt% urea water was allowed to flow through the column until the concentration of the urea water coming out of the column reached 2 wt%. ４＋ Urea was adsorbed onto the XSC. Ti glass tube. ４＋ 2 g of XSC.Ti was added and heated at 150°C for 19 hours. ４＋ When the FTIR spectra of the above were compared before and after heating, a urea peak was observed before heating, but after heating the urea peak disappeared, confirming that urea had been desorbed.

[0069] Example 4: Urea-adsorbed XSC.Ti was prepared in the same manner as in Example 3. ４＋ The temperature inside the column was kept at 80°C, and ultrapure water at 80°C was passed through the column. The urea concentration of the aqueous solution coming out of the column was a maximum of 9.2 wt%. ４＋ It was confirmed that urea is released and concentrated by heating.

[0070] Example 5 270 g of ultrapure water was added to 10 g of 28 wt % ammonia water to prepare 1 wt % ammonia water. 3 mL of this ammonia water and the ion exchanger or ion exchange resin XSC.Na prepared in Preparation Example 1 were added to a 15 mL centrifuge tube. ＋0.1 g of the above was added and shaken overnight at 900 rpm to allow the ammonia to be adsorbed onto the ion exchanger or ion exchange resin. The mixture was then centrifuged at 3000 rpm for 5 minutes, and the supernatant was collected. 50 μL of this supernatant was mixed with 4950 μL of a 5 g / L boric acid solution to neutralize the ammonia. The ammonium ion concentration in this mixture was evaluated by ion chromatography.

[0071] The ammonia concentration in the supernatant was calculated assuming that the obtained ammonium ion concentration was equivalent to the ammonia concentration. The amount of ammonia adsorption (mmol / g) was calculated by dividing the change in the amount of ammonia in the ammonia water before and after adsorption onto the ion exchanger or ion exchange resin by the mass of the ion exchanger or ion exchange resin. The results are shown in Figure 3. Figure 3 shows the relationship between the amount of ammonia adsorption and the ion exchanger or ion exchange resin.

[0072] As shown in FIG. 3, the ion exchange resin XSC.Na ＋ The ammonia adsorption capacity of the ion exchanger in which the Na ions in the ion exchanger are ion-exchanged with other metal ions is ion exchange resin XSC.Na ＋ The amount of ammonia adsorption was greater than that of XSC.Co. ２＋ , XSC.Ni ２＋ , XSC. Cu ２＋ , XSC.Fe ３＋ , and XSC.Mn ２＋ The color of the ion exchanger changed before and after ammonia adsorption.

[0073] That is, gXSC.Co ２＋ The color changes from reddish brown to blackish brown, and gXSC.Ni ２＋ changes from yellow-green to blue, gXSC.Cu ２＋ The color changes from green to blue-purple, and the color of gXSC.Fe ３＋ The color changes from reddish brown to blackish brown, and gXSC.Mn ２＋The color of each ion exchanger changed from orange to dark brown. It is believed that the color change occurred due to ammonia coordinating with the metal ions of the ion exchanger. Based on these results, these ion exchangers can be used as molecular ammonia indicators that show the presence of ammonia in a liquid by a color change. As mentioned above, it is believed that these ion exchangers will also change color when they adsorb amines in general that have amino groups, in addition to ammonia.

[0074] Example 6 A beaker containing 500 mL of 2 wt % aqueous ammonia was prepared. ＋ , gXSC.Cr ３＋ , gXSC.Mn ２＋ , gXSC.Fe ３＋ , gXSC.Co ２ +, gXSC.Ni ２＋ , gXSC.Cu ２＋ , and gXSC.Zn ２＋ Eight petri dishes, each containing 5 g of the ion exchanger, were prepared. The beaker and the petri dishes were placed in a desiccator with a capacity of approximately 10 L and left at room temperature for 46.5 hours to allow the ion exchanger to adsorb ammonia gas. At the end of the experiment, the ammonia gas concentration in the desiccator was 12,000 ppmv.

[0075] As in the case of ammonia adsorption in aqueous ammonia in Example 5, some ion exchangers showed a change in color before and after ammonia gas adsorption. ２＋ The color changes from reddish brown to blackish brown, and gXSC.Ni ２＋ changes from yellow-green to blue, gXSC.Cu ２＋ The color changes from green to blue-purple, and the color of gXSC.Fe ３＋ The color changes from reddish brown to blackish brown, and gXSC.Mn ２＋ The color of the ion exchangers changed from orange to dark brown, respectively. These ion exchangers can be used as molecular ammonia indicators, which show the presence of ammonia in gases by a color change.

[0076] 0.1 g of these ion exchangers with adsorbed ammonia gas was placed in 5 mL of 30 mmol / L aqueous sodium hydrogen sulfate solution and shaken overnight at 25°C and 400 rpm to desorb ammonia with acid. The mixture was then subjected to solid-liquid separation by suction filtration, and the ammonia concentration in the resulting liquid was evaluated by ion chromatography to calculate the amount of ammonia desorbed from the ion exchanger. The results are shown in Figure 4. This amount of ammonia desorbed corresponds to the amount of ammonia adsorbed from the gas phase. As shown in Figure 4, g×SC.Ni ２＋ , gXSC.Cu ２＋ , and gXSC.Zn ２＋ had high ammonia adsorption performance.

[0077] Example 7 8 g of gXSC.Ni ２＋ NH ３ The mixture was placed in a stainless steel column, the inlet was closed, and the column was heated to 140°C. The gas discharged from the outlet was condensed in a stainless steel tube cooled with ice water, and then collected in a gas bag. The ammonia concentration of the liquid in the gas bag was 12.1 wt%. It was found that by heating, ammonia adsorbed on the ion exchanger could be recovered at a high concentration.

[0078] Example 8 8g of gXSC.Ni ２＋ NH ３ The mixture was placed in a stainless steel column, and while the stainless steel column was maintained at a temperature of 140°C, a liquid pump was used to heat ultrapure water to a temperature of 140°C, and the resulting steam was introduced into the inlet at a rate of 0.5 mL / min. The gas discharged from the outlet was condensed in a stainless steel tube cooled with ice water, and recovered as an aqueous ammonia solution. The ammonia concentration of the recovered aqueous ammonia solution was a maximum of 22.1 wt%. It was found that by heating and introducing steam, ammonia adsorbed on the ion exchanger could be recovered at a high concentration.

[0079] Example 9 In order to confirm the change in the amount of ammonia desorbed when the adsorption and desorption of ammonia were repeated, the following ammonia adsorption / desorption cycle test was carried out. First, as an adsorption test, Na was adsorbed onto a strongly acidic ion exchange resin (Amberlite 200CT Na) having sulfonic acid groups. ＋ Ni ２＋The ion exchanger (200CT.Ni obtained in Preparation Example 11) was ２＋ 20 g of 200 CT.Ni ion exchanger was placed in a stainless steel column, the column's port connected to the inlet of a diaphragm pump, the diaphragm pump's outlet connected to one of two ports in the upper air portion of a 20 L tank containing 7 L of 3 wt% aqueous ammonia, and the other port connected to the column's inlet. In this state, the diaphragm pump was operated for 16.5 hours, and a mixed gas of 24,000 ppmv water vapor and 2 vol% ammonia was passed through the column, and the ion exchanger 200 CT.Ni ion exchanger was placed in a stainless steel column, the inlet of the column connected to the inlet of a diaphragm pump, the diaphragm pump's outlet connected to one of two ports in the upper air portion of a 20 L tank containing 7 L of 3 wt% aqueous ammonia, and the other port connected to the column's inlet. ２＋ Ammonia was adsorbed onto the

[0080] Furthermore, as a desorption test, the piping was replaced and ultrapure water and 200CT. Ni were heated with a mantle heater. ２＋ The column containing the ammonium hydroxide was heated to 140°C, and ultrapure water was pumped into the column at 0.1 mL / min using a plunger pump. The liquid leaving the column was cooled in a stainless steel tube immersed in ice water and trapped with boric acid. The concentration of the desorbed aqueous ammonia was calculated by dividing the change in the ammonia ion concentration in the boric acid by the increased weight.

[0081] After cooling the column by air cooling, the piping was replaced, and the above-mentioned adsorption test and desorption test were repeated a total of 30 times, and the cumulative (total) amount of ammonia desorbed per 1 g of adsorbent and the maximum ammonia concentration in the ammonia water obtained by desorption were evaluated.

[0082] FIG. 5 shows the Ni ２＋ 5 is a graph showing the change in the amount of ammonia desorbed when ammonia adsorption and desorption were repeated using a strongly acidic ion exchanger having a pH of 1. As shown in FIG. 5, the maximum ammonia concentration in the ammonia water was about 20 wt %, and the cumulative ammonia amount was generally 3 mmol / g or more. These results demonstrate that an ammonia adsorbent using a strongly acidic ion exchanger can be used repeatedly.

[0083] Example 10 In this example, in order to confirm the change in the amount of urea desorbed when the adsorption and desorption of urea were repeated, the following urea adsorption / desorption cycle test was carried out. First, 1 g of ion exchanger XSC.Ti was used for the adsorption test. ４＋(Na of strongly acidic ion exchange resin having sulfonic acid groups) ＋ Ti ４＋ A stainless steel column was packed with urea (exchanged with urea) and 2 wt % urea water was passed through the column at room temperature at 0.5 mL / min. The urea concentration of the liquid exiting the column was then evaluated by HPLC, and the adsorption amount was calculated by dividing the product of the liquid volume and the concentration change by the mass of the adsorbent (ion exchanger). After adsorption, a desorption test was performed by heating the column to 80°C, pumping ultrapure water heated to 80°C into the column using a plunger pump, and evaluating the urea concentration of the liquid recovered from the outlet by HPLC. The desorption amount was calculated by dividing the product of the liquid volume and the concentration change by the mass of the adsorbent. This adsorption / desorption test was repeated 30 times.

[0084] FIG. ４＋ 7 is a graph showing the change in the amount of urea desorbed when urea adsorption and desorption are repeated on a strongly acidic ion exchanger having Ti. ４＋ 8 is a graph showing the cumulative amount of urea adsorbed when urea was adsorbed again after 30 cycles of adsorption and desorption of urea on a strongly acidic ion exchanger having Ti. ４＋ 1 is a graph showing the cumulative amount of urea desorbed when 30 cycles of urea adsorption and desorption were repeated on a strongly acidic ion exchanger having the formula (I) and the urea was desorbed again.

[0085] As shown in Figure 6, the amount of urea desorbed remained constant at approximately 40 mg / g regardless of the number of cycles. In addition, as shown in Figures 7 and 8, no decrease in the amount of urea adsorbed or desorbed was observed even after 30 cycles of urea adsorption and desorption. These results demonstrate that the urea adsorbent using a strongly acidic ion exchanger containing metal ions can be used repeatedly.

[0086] Example 11 In this example, a strongly acidic ion exchange resin (Amberlite 200CT Na) having sulfonic acid groups was used to adsorb urea. ＋ Sn ４＋ The ion exchanger (200CT.Sn obtained in Preparation Example 12) was ４＋0.5 g of the adsorbent (200CT.Sn) was placed in a 15 mL centrifuge tube together with 5 mL of 10 wt % urea water and shaken at 900 rpm for 5 hours. After shaking, the solid was separated using a paper filter, washed with ultrapure water, and then left to stand at 60°C for 17 hours or more. ４＋ The amount of adsorption was calculated by dividing the product of the liquid volume and the concentration change by the mass of the adsorbent, and the amount of urea adsorption was found to be 126 mg / g.

[0087] Fig. 9 is a schematic diagram showing the recovery of urea from an adsorbent made of a strongly acidic ion exchanger containing metal ions, and Fig. 10 is an image showing a glass container from which solid urea has been recovered.

[0088] 1 g of the adsorbent with urea adsorbed thereon was placed in the vertically long glass container shown in Figure 10, and vacuum was applied from above at 100°C for 43.5 hours. As a result, a total of 2 mg of white solid matter was generated on the glass surface. When this solid matter was dissolved in water and measured by HPLC, a peak corresponding to urea was confirmed. This demonstrated that solid urea can be recovered using this method.

[0089] Example 12 In this example, XSC.Co was used to adsorb trimethylamine. ２＋ , XSC.Ni ２＋ , XSC. Cu ２＋ , XSC.Mn ２＋ , XSC.Fe ３＋ , or XSC.Na ＋ 0.1 g of the ion exchanger was placed in a 15 mL centrifuge tube together with 0.4 mL of a 12 wt % aqueous trimethylamine solution and allowed to stand for 24 hours. The supernatant solution was then collected, and the concentration of the aqueous trimethylamine solution in the supernatant was measured from the change in the intensity of the trimethylamine spectrum by FTIR. The adsorption amount was calculated by dividing the product of the liquid volume and the change in concentration by the mass of the adsorbent.

[0090] 11 is a graph showing the amount of trimethylamine adsorbed in the aqueous solution of Example 12. As shown in FIG. ＋ Compared to XSC.Co ２＋ , XSC.Ni ２＋ , XSC. Cu ２＋ , XSC.Mn ２＋ and XSC.Fe３＋ showed a high adsorption amount (Figure 11). ２＋ , XSC.Ni ２＋ , XSC. Cu ２＋ , and XSC.Fe ３＋ In the case of XSC.Co, the color of the ion exchanger changed before and after trimethylamine adsorption. ２＋ The color changes from reddish brown to blackish brown, and gXSC.Ni ２＋ changes from yellow-green to green, gXSC.Cu ２＋ The color changes from green to blue-purple, and the color of gXSC.Fe ３＋ The color of each ion exchanger changed from reddish brown to blackish brown. It is believed that the color change occurred due to ammonia coordinating with the metal ions of the ion exchanger. These results demonstrate that these ion exchangers can be used as trimethylamine indicators, which show the presence of trimethylamine in liquids through a color change.

[0091] Example 13 In this example, XSC.Co was used to adsorb butylamine. ２＋ , XSC.Ni ２＋ , XSC. Cu ２＋ , XSC.Mn ２＋ , XSC.Fe ３＋ or XSC.Na ＋ 0.1 g of the ion exchanger was placed in a 15 mL centrifuge tube together with 0.4 mL of a 15 wt % aqueous butylamine solution and allowed to stand for 24 hours. The supernatant solution was then collected, and the concentration of the butylamine solution in the supernatant was measured from the change in the intensity of the butylamine spectrum by FTIR. The adsorption amount was calculated by dividing the product of the liquid volume and the change in concentration by the mass of the adsorbent.

[0092] 12 is a graph showing the amount of butylamine adsorbed in the aqueous solution of Example 13. As shown in FIG. ＋ Compared to XSC.Co ２＋ , XSC.Ni ２＋ , XSC. Cu ２＋ , XSC.Mn ２＋ and XSC.Fe ３＋ showed a high adsorption amount. XSC.Co ２＋ , XSC.Ni ２＋ , XSC. Cu ２＋ , and XSC.Fe ３＋In the case of XSC.Co, the color of the ion exchanger changed before and after butylamine adsorption. ２＋ The color changes from reddish brown to blackish brown, and XSC.Ni ２＋ changes from yellow-green to green, and XSC. Cu ２＋ The color changes from green to blue-purple, and XSC.Fe ３＋ , XSC.Mn ２＋ The color of each ion exchanger changed from reddish brown to blackish brown. It is believed that the color change occurred due to coordination of butylamine with the metal ions of the ion exchanger. These results demonstrate that these ion exchangers can be used as butylamine indicators, which show the presence of butylamine in liquids through a color change.

[0093] Example 14 2 mL of 12 wt% trimethylamine water and gXSC.Co ２＋ , XSC.Ni ２＋ , gXSC.Cu ２＋ , gXSC.Mn ２＋ or gXSC.Fe ３＋ A glass petri dish was prepared, in which a PP dish containing approximately 0.01 g of ion exchanger was placed so that the ion exchanger and trimethylamine water did not come into contact with each other. The glass petri dish was left at room temperature for 20 hours, allowing each ion exchanger to adsorb vaporized trimethylamine gas. As with the adsorption of trimethylamine in water in Example 12, some ion exchangers showed a change in color before and after adsorption of trimethylamine gas. That is, gXSC.Co ２＋ The color changes from reddish brown to blackish brown, and gXSC.Ni ２＋ changes from yellow-green to green, gXSC.Cu ２＋ From green to blue, gXSC.Fe ３＋ The color changes from reddish brown to blackish brown, and gXSC.Mn ２＋ The color of the ion exchangers changed from orange to dark brown, respectively. These results demonstrate that these ion exchangers can be used as trimethylamine indicators, which show the presence of trimethylamine in gases by a color change.

[0094] Example 15 2 mL of 15 wt% butylamine water and gXSC.Co ２＋ , XSC.Ni ２＋ , gXSC.Cu ２＋ , gXSC.Mn ２＋ or gXSC.Fe３＋ A glass petri dish was prepared, in which a PP dish containing approximately 0.01 g of ion exchanger was placed so that the ion exchanger and butylamine water did not come into contact with each other. The glass petri dish was left at room temperature for 20 hours, allowing each ion exchanger to adsorb vaporized butylamine gas. As with the adsorption of butylamine in water in Example 13, some ion exchangers showed a change in color before and after adsorption of butylamine gas. That is, gXSC.Co ２＋ The color changes from reddish brown to blackish brown, and gXSC.Ni ２＋ changes from yellow-green to green, gXSC.Cu ２＋ From green to blue, gXSC.Fe ３＋ The color changes from reddish brown to blackish brown, and gXSC.Mn ２＋ The color of the ion exchangers changed from orange to dark brown, respectively. These results demonstrate that these ion exchangers can be used as butylamine indicators that show the presence of butylamine in gases by a color change.

Claims

1. A molecular adsorbent that adsorbs polar molecules, the active ingredient of which is an ion exchanger having an ion exchange resin with a strongly acidic ion exchange group and a metal ion or a complex of the metal ion that has been ion-exchanged by the ion exchange group, the polar molecule containing a nitrogen atom having an unshared electron pair, the metal ion being a trivalent or higher metal ion, Co ２＋ , Cu ２＋ , Ni ２＋ , Mn ２＋ , V ２＋ , Cs ＋ , Rb ＋ , and K ＋ A molecular adsorbent that is one or more of the following:

2. In the method according to claim 1, the trivalent or higher metal ion is Fe. ３＋ , Cr ３＋ , Al ３＋ , Ti ３＋ , In ３＋ , Ru ３＋ , Ti ４＋ , Zr ４＋ , Sn ４＋ and Hf ４＋ A molecular adsorbent that is one or more of the following:

3. The molecular adsorbent according to claim 1, wherein the polar molecule is at least one of ammonia, amine and urea.

4. In the method according to claim 3, the polar molecule is urea, and the metal ion is Fe. ３＋ , Ti ３＋ , Ru ３＋ , Zr ４＋ , Hf ４＋ , Sn ４＋ and Cs ＋ A molecular adsorbent that is one or more of the following:

5. In the method according to claim 3, the polar molecule is ammonia, and the metal ion is Ni. ２＋ and Cu ２＋ A molecular adsorbent that is at least one of the above.

6. In the method according to claim 3, the polar molecule is at least one of trimethylamine and butylamine, and the metal ion is Co ２＋ , Ni ２＋ , Cu ２＋ , Mn ２＋ and Fe ３＋ The molecular adsorbent is one or more selected from the group consisting of:

7. An indicator for ammonia and amines, comprising an ion exchanger having an ion exchange resin with a strongly acidic ion exchange group and a metal ion or a complex of the metal ion that has been ion-exchanged by the ion exchange group, and determining the adsorption of at least one of ammonia and amines to the ion exchanger by a color change, wherein the metal ion is Co ２＋ , Ni ２＋ , Cu ２＋ , Fe ３＋ , or Mn ２＋ That is, the indicator.

8. The indicator according to claim 7, wherein the adsorption of ammonia is determined by a color change.

9. The indicator of claim 7, wherein the amine is at least one of trimethylamine and butylamine.

10. An ion exchange resin having an ion exchange group which is a strongly acidic group, and a trivalent or higher metal ion, Co, which is ion-exchanged by the ion exchange group. ２＋ , Cu ２＋ , Ni ２＋ , Mn ２＋ , V ２＋ , Zn ２＋ , Cs ＋ , Rb ＋ , and K ＋ and a complex thereof, by contacting a gas or liquid containing a polar molecule including a nitrogen atom having an unshared electron pair with an ion exchanger having one or more metal ions selected from the group consisting of 1 to 5, thereby adsorbing the polar molecule; and a condensing step of heating the ion exchanger to which the polar molecule has been adsorbed, and condensing a gas generated from the ion exchanger.

11. A method for concentrating polar molecules according to claim 10, wherein the condensation step comprises heating the ion exchanger to a temperature of 60° C. or higher and lower than the heat resistance temperature of the ion exchanger.

12. A method for concentrating polar molecules according to claim 10 or 11, wherein the condensing step comprises heating the ion exchanger while contacting it with water vapor.

13. In claim 10 or 11, the trivalent or higher metal ion is Fe. ３＋ , Cr ３＋ , Al ３＋ , Ti ３＋ , In ３＋ , Ru ３＋ , Ti ４＋ , Zr ４＋ , Sn ４＋ and Hf ４＋ wherein the polar molecule is at least one of ammonia and urea.

14. In claim 12, the trivalent or higher metal ion is Fe. ３＋ , Cr ３＋ , Al ３＋ , Ti ３＋ , In ３＋ , Ru ３＋ , Ti ４＋ , Zr ４＋ , Sn ４＋ and Hf ４＋ wherein the polar molecule is at least one of ammonia and urea.

15. A method for recovering a polar molecule concentrated by the method for concentrating a polar molecule according to claim 10 or 11, wherein the polar molecule is urea, the recovery method comprising the steps of heating a container containing the ion exchanger on which urea has been adsorbed, and applying negative pressure to the upper part of the container to cause suction, thereby precipitating solid urea.

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