Ammonia recovery method and ammonia recovery apparatus

Abstract

To provide a method and an apparatus for recovering ammonia in exhaust gas as a solid under more convenient, inexpensive and mild conditions than those under a controlled temperature and pressure.SOLUTION: Ammonia bicarbonate aqueous solution is brought into contact with an ammonia adsorbed PB derivative represented by general formula (1), and after ammonia is desorbed, carbon dioxide is introduced to recover the ammonium carbonate precipitated in the solution as a solid. AxM[M'(CN)6]y.zH2O...(1) [In formula (1), x is 0-3, y is 0.1-1.5, z is 0-6, A is hydrogen, ammonium cation, alkali metal ion, etc., and M, M 'are predetermined cations.]SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a method and apparatus for recovering ammonia, and more particularly to a method and apparatus for recovering ammonia as a solid after desorbing ammonia from an adsorbent that has adsorbed ammonia in the gas phase. [Background technology]

[0002] Ammonia is produced in large quantities chemically from nitrogen in the air using hydrogen and energy via the Haber-Bosch process. The majority of this ammonia is used in chemical fertilizers and synthetic fibers. After these products are discarded, ammonia is released into the environment through decomposition, causing various problems. Much of PM2.5 pollution is caused by ammonia emitted from agriculture, and eutrophication is also due to ammoniacal nitrogen contained in wastewater.

[0003] Furthermore, ammonia is one of the substances that cause foul odors from livestock farming, and it is generated not only from livestock barns but also from the decomposition of manure in composting facilities. Ammonia is also generated from factories and sewage treatment plants, but these require treatment processes that convert it to nitrogen through nitrification and denitrification, for example, by using biological processes. However, these treatment processes require a lot of electricity and energy.

[0004] Therefore, there is a need to recover ammonia that can diffuse into the environment, thereby achieving both a reduction in processing energy and the utilization of exhaust gas as a resource. Many ammonia-derived resources include urea and ammonium salts. Among these, ammonium bicarbonate, ammonium carbamate, ammonium sesquicarbonate, and ammonium carbonate have applications in confectionery, rubber compounding, pharmaceuticals, and medicines, and their constituent ammonia and carbon dioxide are also raw materials for urea. In recent years, ammonia has also shown promise as a fuel.

[0005] Methods for recovering ammonia from exhaust gas include methods that recover ammonia by liquefaction or solidification through cooling (Patent Documents 1 and 2), but these require cooling to the liquefaction temperature (-77.7°C) and increasing the pressure.

[0006] In addition to these methods of recovery by liquefaction or solidification, the use of adsorbents to recover ammonia is also widely used in industry. Materials such as activated carbon (Patent Document 3), molecular sieves, zeolites (Patent Document 4), and polymers containing sulfonic acid, also known as Amberlyst® (Non-Patent Document 1), are mainly used for ammonia adsorption, but these adsorbents have relatively low selectivity and adsorption capacity. In contrast, Prussian blue (hereinafter sometimes abbreviated as "PB") derivatives are known as preferred adsorbents because they have high selectivity for ammonia and a very large adsorption capacity.

[0007] Various methods are being investigated for desorbing ammonia from adsorbents that have adsorbed it. For example, Patent Document 5 and Non-Patent Document 2 propose desorbing ammonia from a PB derivative that has adsorbed ammonia using an aqueous solution of salt or strong acid, or ultrapure water. Furthermore, Patent Document 6 proposes desorbing ammonia by contacting a PB derivative that has adsorbed ammonia with carbon dioxide and water. [Prior art documents] [Patent Documents]

[0008] [Patent Document 1] Japanese Patent Publication No. 2011-207672 [Patent Document 2] Japanese Patent Publication No. 2017-77555 [Patent Document 3] Japanese Patent Publication No. 2016-160170 [Patent Document 4] Japanese Patent Publication No. 2000-317246 [Patent Document 5] International Publication No. 2015-186819 [Patent Document 6] International Publication No. 2020-080302 [Non-Patent Document]

[0009] [Non-Patent Document 1] J. Helminen et al, J. Chem. Eng. Data 2001, 46 (2), 391. [Non-Patent Document 2] A. Takahashi et al, J. Am. Chem. Soc, 2016, 138, 6376. [Non-Patent Document 3] D. Sutter et al, Chem. Eng. Sci. 2015, 133, 中譯:170 - 180. [Summary of the Invention] [Problems to be Solved by the Invention]

[0010] However, in the methods of Patent Documents 5 and 6 and Non-Patent Document 2, since the ammonia that has been desorbed is obtained in a solution state, there are problems when using it as a resource depending on its concentration. For example, when using an aqueous ammonia solution of low concentration as a resource, it can be considered for use as liquid fertilizer, but in this case, transportation to agricultural land is required. Especially if there is no farm as the destination nearby, the transportation cost becomes excessive and utilization is difficult. Although it is possible to concentrate by methods such as ammonia stripping to increase the concentration, implementing those concentration methods also requires corresponding energy. Also, in Patent Document 6, it is described that one or more of ammonium hydrogen carbonate, ammonium carbonate, and ammonium carbonate ion are recovered as a liquid or a solid, but to make it a solid, processing such as heating is required, which requires energy. When recovered as a liquid, if the liquid cannot be reused, energy is required for wastewater treatment, etc.

[0011] This invention was made in view of the current situation, and aims to provide a method and apparatus that can recover ammonia in solid form after desorbing ammonia adsorbed on a PB derivative by a simple and inexpensive method. [Means for solving the problem]

[0012] As a result of diligent research, the inventors of the present invention have found that the above problems can be solved by using an aqueous solution of ammonium bicarbonate instead of the desorption liquid described in Patent Documents 5 and 6 and Non-Patent Document 2, and have completed the present invention.

[0013] In other words, one aspect of the present invention for solving the above problem is, A step of desorbing ammonia adsorbed onto a Prussian blue derivative represented by the following general formula (1) into the solution by contacting it with an aqueous solution of ammonium bicarbonate, A step of contacting a liquid containing the detached ammonia with carbon dioxide to precipitate solid ammonia carbonate, and The process of separating the precipitated ammonia carbonate from the ammonium bicarbonate aqueous solution, This is a method for recovering ammonia containing [a specific substance]. A x M[M'(CN)6] y ·zH2O···(1) [In formula (1), x is a number from 0 to 3, y is a number from 0.1 to 1.5, z is a number from 0 to 6, A is a cation representing at least one or more combinations selected from the group consisting of hydrogen, ammonium cations, alkali metal ions, and alkaline earth metal ions, M and M' are each independently selected, M is a cation representing at least one or more combinations selected from the group consisting of atoms with atomic numbers from 3 to 83 (excluding hydrogen, ammonium cations, alkali metal ions, and alkaline earth metal ions), and M' is at least one cation selected from the group consisting of atoms with atomic numbers from 3 to 83 (excluding hydrogen, ammonium cations, alkali metal ions, and alkaline earth metal ions).]

[0014] In the ammonia recovery method of the present invention, in the desorption step, the ammonia gas is brought into contact with the Prussian blue derivative represented by the general formula (1) and adsorbed, thereby enabling the steps of adsorbing ammonia and desorbing the adsorbed ammonia to be performed simultaneously or alternately.

[0015] Furthermore, in the ammonia recovery method of the present invention, it is preferable to include a step of using the liquid obtained after the separation of the ammonia carbonate as a liquid for desorbing the ammonia adsorbed onto the Prussian blue derivative represented by the general formula (1).

[0016] Furthermore, in the ammonia recovery method of the present invention, it is preferable that the ammonium bicarbonate aqueous solution is a saturated ammonium bicarbonate aqueous solution, and it is also preferable to add a water-soluble organic solvent to the ammonium bicarbonate aqueous solution.

[0017] Another aspect of the present invention is, The device includes an adsorbent installation section for installing an adsorbent made of a Prussian blue derivative represented by the following general formula (1), and an ammonia adsorption / desorption section for contacting the adsorbent, which has adsorbed ammonia, with an aqueous ammonium bicarbonate solution to desorb the adsorbed ammonia into the liquid, A solid precipitation unit is provided in which carbon dioxide is introduced into the desorbed liquid discharged from the adsorption / desorption unit to precipitate ammonia carbonate, A solid-liquid separation unit separates the desorbed liquid containing solid ammonia carbonate discharged from the solid deposition unit into solid and liquid. This is an ammonia recovery device that has [a certain feature]. A x M[M'(CN)6] y ·zH2O···(1) [In formula (1), x is a number from 0 to 3, y is a number from 0.1 to 1.5, z is a number from 0 to 6, A is a cation representing at least one or more combinations selected from the group consisting of hydrogen, ammonium cations, alkali metal ions, and alkaline earth metal ions, M and M' are each independently selected, M is a cation representing at least one or more combinations selected from the group consisting of atoms with atomic numbers from 3 to 83 (excluding hydrogen, ammonium cations, alkali metal ions, and alkaline earth metal ions), and M' is at least one cation selected from the group consisting of atoms with atomic numbers from 3 to 83 (excluding hydrogen, ammonium cations, alkali metal ions, and alkaline earth metal ions).]

[0018] In the ammonia recovery apparatus of the present invention, it is preferable to provide means for introducing the liquid obtained after the solid ammonia carbonate has been separated into the adsorption / desorption section. [Effects of the Invention]

[0019] According to the present invention, ammonia adsorbed from an adsorbent that has adsorbed ammonia in the gas phase, such as exhaust gas, can be recovered inexpensively and efficiently as solid ammonia carbonate. Furthermore, according to the present invention, the aqueous sodium bicarbonate solution remaining after ammonia recovery can be reused as a desorption solution for ammonia adsorbed on the PB derivative. Moreover, in the ammonia desorption process, by mixing the aqueous ammonium bicarbonate solution used as the desorption solution with a water-soluble organic solvent such as alcohol, solid precipitation is promoted, and ammonia can be recovered as a solid even when the ammonia concentration of the adsorbed gas is low. [Brief explanation of the drawing]

[0020] [Figure 1] Diagram illustrating the principle of the ammonia recovery method of the present invention. [Figure 2] A diagram showing the steps of one embodiment of the ammonia recovery method of the present invention. [Figure 3]This diagram schematically shows an example of a column suitable for adsorbing and desorbing ammonia onto a PB derivative in the ammonia recovery method of the present invention. [Figure 4] A diagram illustrating an outline of one embodiment of the ammonia recovery device of the present invention. [Figure 5] Diagram showing the process of Example 1 [Figure 6] Photograph of the precipitate formed after carbon dioxide injection in Example 1. [Figure 7] This figure shows the FTIR spectra of the precipitate obtained in Example 1 and commercially available ammonium bicarbonate (NH4HCO3). [Figure 8] A diagram showing the ammonia (NH3) balance before and after desorption in Example 1. [Figure 9] A diagram showing the balance of ammonia (NH3) in the aqueous solution before and after carbon dioxide injection in Example 1. [Figure 10] This figure shows the changes in the amount of NH3 adsorbed on the column and the concentration of NH4+ in the desorbed liquid in Example 4. [Figure 11] This figure shows the changes in the amount of NH3 adsorbed on the column and the concentration of NH4+ in the desorbed liquid in Example 5. [Modes for carrying out the invention]

[0021] The ammonia recovery method and ammonia recovery apparatus of the present invention are characterized by the following: ammonia adsorbed onto a PB derivative represented by the above general formula (1) is contacted with an aqueous solution of ammonium bicarbonate to desorb into the liquid, and then carbon dioxide is contacted with the liquid containing the desorbed ammonia to precipitate solid ammonia carbonate.

[0022] The principle of the ammonia recovery method of the present invention will be explained below with reference to Figure 1. It is known that ammonia dissolves in a saturated aqueous solution of ammonium bicarbonate (see Non-Patent Document 3). Figure 1 is a three-component phase diagram of ammonia, carbon dioxide, and water at 10°C, as published in Non-Patent Document 3. In the figure, the composition is expressed as a mass ratio, S represents the solid phase, L represents the liquid phase, and V represents the gas phase. BC represents ammonium bicarbonate, SC represents ammonium sesquicarbonate, CB represents ammonium carbonate, and CM represents ammonium carbamate. The arrows and Japanese explanations in the figure were added by the inventors.

[0023] For example, when ammonia adsorbed onto a PB derivative is desorbed using a saturated ammonium bicarbonate aqueous solution, the composition of the saturated ammonium bicarbonate aqueous solution changes along the arrow labeled "Desorption" in the figure. Next, when carbon dioxide is introduced into the saturated ammonium bicarbonate aqueous solution after ammonia has been desorbed, the composition of the system changes along the arrow labeled "CO2 Introduction," and phase separation occurs in the solid-liquid phase separation region as shown by the two arrows, resulting in two phases: ammonium bicarbonate and saturated ammonium bicarbonate aqueous solution, with the solid precipitated. The composition that can be used as a desorbent is the composition corresponding to the L region to the right of the S+L region in Figure 1.

[0024] The following describes embodiments of the present invention (hereinafter referred to as "these embodiments"), but these are for illustrative purposes only and do not limit the scope of the present invention. In this specification, the "~" symbol indicating a numerical range is used to mean that the numbers before and after it are included as the lower and upper limits, respectively.

[0025] Methods for recovering ammonia The ammonia recovery method of this embodiment comprises the steps of: contacting the ammonia adsorbed on the PB derivative with an aqueous ammonium bicarbonate solution to desorb it (hereinafter sometimes referred to as the "desorption step"); contacting the liquid containing the desorbed ammonia with carbon dioxide to precipitate solid ammonia carbonate (hereinafter sometimes referred to as the "precipitation step"); and separating the precipitated ammonia carbonate from the aqueous ammonium bicarbonate solution.

[0026] Figure 2 is a process diagram illustrating an example of the ammonia recovery method of this embodiment. It shows the steps of: contacting the ammonia adsorbed on the PB derivative with a desorption solution (aqueous solution of ammonium bicarbonate) to desorb the ammonia into the liquid; separating the PB derivative from the desorption solution; contacting the desorption solution after the separation of the PB derivative with carbon dioxide to precipitate ammonium bicarbonate as a solid; and recovering the precipitate by solid-liquid separation of the desorption solution from which the solid has precipitated. As shown in the figure, the PB derivative and the desorption solution can be reused. In this embodiment, these processes may be batch-based or flow-based, either entirely or partially. The following will explain each point in detail.

[0027] [Ammonia adsorbent] In this embodiment, the ammonia adsorbent used is called a PB derivative. Its components are a metal ion (a positively charged cation) and a cyano group (a negatively charged anion, CN) which is a type of ligand that bridges these metal ions. - ) consists of a series of compounds called metal cyano complexes, which structurally have a hexacyano metal ion. PB derivatives have the general formula: A x M[M'(CN)6] yIt is represented as zH2O(A, M, M' = metal ions) and has a nanopore structure that can capture the target gas inside. The size of this nanopore structure, or pore size, is in the range of 0.3 to 0.6 nm, and because they are arranged in a regularly repeating manner, it has a very large surface area and high selectivity, allowing it to efficiently adsorb and deodorize ammonia, a type of odor gas.

[0028] Metal ions M and M' are independently selected from metal elements with atomic numbers 3 to 83. However, in metal ions M and M', cations selected from the group consisting of A in the general formula (hydrogen, ammonium cation, lithium, sodium, potassium, rubidium, cesium, francium) and alkaline earth metals (magnesium, calcium, strontium, barium, radium) are excluded. For example, in the general formula, M can be a metal ion that is one or more positive (+) ions selected from the group consisting of vanadium, chromium, manganese, iron, ruthenium, cobalt, rhodium, nickel, palladium, platinum, copper, silver, zinc, indium, lanthanum, europium, gadolinium, and lutetium. M may contain a mixture of two or more cations, which are present in the PB derivative to maintain the overall charge balance. In M', one or more metal ions selected from the group consisting of vanadium, chromium, molybdenum, tungsten, manganese, iron, ruthenium, cobalt, nickel, platinum, and copper are mentioned. Among the selected M', iron and cobalt are particularly preferred from the viewpoint of cyanide stability.

[0029] By combining metal ions M and M', the adsorption capacity, adsorption rate, selectivity, and performance of ammonia can be altered and controlled, enabling ammonia adsorption. When M is indium and M' is iron(II), or when M is cobalt(III) and M' is cobalt(II), these PB derivatives are preferable as adsorption and desorption derivatives because they allow for quantitative and stable adsorption of ammonia from low to high concentrations. Various other combinations are also possible, for example, M=Fe 3+ , M'=Fe2+ or M = Cu 2+ 、M’ = Fe 2+ or M = Co 2+ 、M’ = Co 3+ or M = Cu 3+ 、M’ = Co 2+ Examples of combinations include etc.

[0030] A is a cation representing one or a combination of two or more selected from the group consisting of hydrogen, ammonium cation, and alkali metals such as lithium, sodium, potassium, rubidium, cesium, francium, and alkaline earth metals such as magnesium, calcium, strontium, barium, radium. There may be a case where two or more of the cations of A are mixed, and there is a value of x to maintain the overall charge balance. In the above formula, x represents a numerical value of 0 to 3, y represents a numerical value of 0.1 to 1.5, and z represents a numerical value of 0 to 6.

[0031] The nano-void structure of the PB derivative represented by the general formula is as described above. Also, even when various metal elements listed above are adopted as the metal ions A, M, and M’, the pores efficiently adsorb Cs ions (Cs + 、ionic radius = 0.183 nm) with high selectivity. It is also known that the nano-void structure surrounded by CN with a negative charge, which is one of the skeletons of the PB derivative, that is, the pores, show a good charge and spatial matching with the positively charged Cs ions, and efficient adsorption is considered to be realized even when A, M, and M’ are various metal elements. Ammonium ion (NH4 + 、ionic radius = 0.175 nm), which is one of the ammonia species of the present invention, has a positive charge and its size is very similar to that of Cs ions. It is considered to be a factor for the PB derivative to efficiently adsorb ammonia species even when A, M, and M’ are various metal elements. Even when A, M, and M’ in the general formula are changed to various metal elements as listed above, a similar ammonia adsorption effect is considered to be obtained.

[0032] In the general formula of the aforementioned PB derivative, metal ions M and M' are selected from atoms with atomic numbers 3 to 83, either identical or different combinations, to synthesize a material (mainly in powder form) with a specific composition. By changing the combination of A, M, and M', the properties and capabilities related to the rate and volume of ammonia adsorption and desorption, the adsorption strength of the adsorbed ammonia chemical species, pressure, temperature, and humidity can be changed and adjusted.

[0033] Furthermore, the PB derivative of this embodiment includes all forms that contain it, such as mixtures with polymer compounds, conjugates having chemical bonds, mixtures with glass wool, zeolites, molecular sieves, and other inorganic materials, forms fixed to filters or plates made of organic polymers or inorganic materials such as metals or oxides, and forms in granular, columnar, or pellet form. In addition, the embodiment also includes forms in which the PB derivative is packed or wrapped in a porous container or a two-dimensional sheet that can pass gas, or forms in which it is mixed with a gel, ink, film, resin, powder, sand, or liquid such as water, alcohol, oil, organic matter, or ionic liquid.

[0034] [Adsorption of ammonia onto PB derivatives] One method for adsorbing ammonia onto a PB derivative is to bring the PB derivative into contact with a gas or liquid containing ammonia, thereby forming a PB derivative on which ammonia has been adsorbed. Conditions suitable for adsorption can be achieved by adjusting temperature, pressure, humidity, ammonia mixture state, pH, concentration, and liquid-to-solid ratio. A relatively low temperature (e.g., below 150°C) and a relatively high pressure (e.g., above 1 atmosphere (100 kPa)) are desirable, but humidity, ammonia mixture state, pH, and concentration should be adjusted depending on the type of PB derivative. The range of temperature, pressure, and humidity for adsorption varies depending on the PB derivative, but for example, a relatively low temperature selected from below 150°C is preferred. A pressure selected from above 1 atmosphere (100 kPa) is preferred, and a humidity selected from above 1% RH is preferred.

[0035] [Desorption process] (A liquid for desorbing ammonia adsorbed onto PB derivatives) In this embodiment, an aqueous solution of ammonium bicarbonate is used as the liquid (desorption solution) for desorbing ammonia adsorbed on the PB derivative. Furthermore, an aqueous solution of ammonium bicarbonate can be considered as a solution in which ammonia and carbon dioxide are dissolved in water in a molar ratio of 1:1. At 20°C, when 21.6 g of ammonium bicarbonate is dissolved in 100 mL of water, it becomes a saturated aqueous solution of ammonium bicarbonate.

[0036] In this embodiment, the eluent includes the following: • A saturated aqueous solution of ammonium bicarbonate (NH4HCO3) prepared by dissolving ammonium bicarbonate until it no longer dissolves. • Aqueous ammonium bicarbonate solution in which the ammonia and / or carbon dioxide concentrations have decreased due to volatilization. • Aqueous ammonium bicarbonate solution containing detached ammonia, resulting in increased ammonium ion concentration. • A saturated ammonium bicarbonate aqueous solution whose saturation concentration has been altered by mixing it with a water-soluble organic solvent. • Aqueous solution of ammonium bicarbonate after separating the ammonia carbonate that has precipitated into a solid state.

[0037] In this embodiment, the composition of the desorbent liquid may be any composition corresponding to the L region to the right of the S+L region in Figure 1, as described above. However, the ammonia concentration in the desorbent liquid is preferably low from the viewpoint of desorption, and preferably close to the saturation concentration from the viewpoint of precipitation. To prevent unintended solid precipitation in the apparatus, a concentration lower than the saturation concentration is preferable. From the above, the ammonia molar concentration is preferably 80% or more of the saturated molar concentration of ammonium bicarbonate from the viewpoint of desorption, preferably 90% to 100% of the saturated molar concentration of ammonium bicarbonate from the viewpoint of precipitation efficiency, and preferably 90% to 95% of the saturated molar concentration of ammonium bicarbonate from the viewpoint of precipitation within the apparatus.

[0038] Furthermore, from the perspective of desorption, the molar concentration of carbon dioxide is preferably 80% or more of the saturated molar concentration of ammonium bicarbonate; from the perspective of precipitation efficiency, it is preferably 90% to 100% of the saturated molar concentration of ammonium bicarbonate; and from the perspective of precipitation within the apparatus, it is preferably 90% to 95% of the saturated molar concentration of ammonium bicarbonate.

[0039] The aforementioned saturation concentration changes with temperature or the mixing of water-soluble organic solvents, but it is preferable for both desorption and precipitation to occur at a lower saturation concentration. In this embodiment, the temperature of the desorbed liquid is preferably 0°C to 40°C from the viewpoint of desorption, and more preferably 0°C to 25°C from the viewpoint of precipitation. Any solvent that can lower the saturation concentration will suffice as a water-soluble organic solvent. Examples include water-soluble alcohols such as methanol, ethanol, and propanol, as well as solvents that dissolve in water but do not dissolve ammonia carbonate, such as acetone.

[0040] In this embodiment, ammonia adsorbed onto the PB derivative is desorbed into the solution by contacting it with an aqueous solution of ammonium bicarbonate. The ammonia desorbed into the solution is then precipitated in the solution by contacting the solution containing the desorbed ammonia with carbon dioxide in the [precipitation step] described later. The order, conditions, and manner of processing in these steps include all possible cases. For example, (A) A method of introducing carbon dioxide into the liquid after separating the PB derivative, which has ammonia adsorbed onto it, by bubbling, after contacting it with an aqueous solution of ammonium bicarbonate, that is, after immersing it in the liquid or passing the liquid through it. (B) A method of introducing carbon dioxide into a liquid by bubbling while contacting a PB derivative on which ammonia has been adsorbed with an aqueous solution of ammonium bicarbonate, (C) A method of spraying a liquid obtained after separating a PB derivative on which ammonia has been adsorbed into an aqueous solution of ammonium bicarbonate into a container where carbon dioxide is present, after contacting the PB derivative with an aqueous solution of ammonium bicarbonate. (D) The PB derivative with adsorbed ammonia is brought into contact with an aqueous ammonium bicarbonate solution, and the ammonia carbonate is precipitated and recovered by introducing carbon dioxide. did The liquid is then brought back into contact with the PB derivative and reused repeatedly. These are some examples. Furthermore, these processes in this embodiment may be carried out in a batch or flow manner. Furthermore, for each of the above (A) to (D), the temperature, pressure, and environmental conditions are appropriately selected according to the respective configuration.

[0041] (Separation of PB derivative and eluate) As described above, in this embodiment, the PB derivative and the eluate can be separated before introducing carbon dioxide (see Figure 2), or carbon dioxide can be introduced while the PB derivative is in contact with the eluate. However, if the PB derivative and the eluate are separated before introducing carbon dioxide, the method is not particularly limited.

[0042] (Ammonia adsorption in the desorption process) In this embodiment, in the desorption step, ammonia (NH3) is brought into contact with the PB derivative to adsorb ammonia onto the PB derivative, thereby enabling the adsorption of ammonia onto the PB derivative and the desorption step to be performed simultaneously, or the adsorption of ammonia onto the PB derivative and the desorption step to be performed alternately.

[0043] Figure 3 schematically shows an example of a column suitable for adsorbing and desorbing ammonia onto PB derivatives. The column body, which is packed with granular PB derivatives, is configured to introduce NH3 gas from one direction to bring the NH3 gas into contact with the PB derivatives, and to introduce an aqueous solution of ammonium bicarbonate, which is the desorbent, from another direction perpendicular to the first direction to bring it into contact with the NH3 adsorbed on the PB derivatives. By using this column, it becomes possible to introduce NH3 gas followed by the desorbed liquid, to introduce NH3 gas and the desorbed liquid simultaneously, or to introduce NH3 gas and the desorbed liquid alternately. Furthermore, when using this column, since the granulated PB derivative is packed into the column body with a mesh, it becomes possible to separate the PB derivative from the ammonia-containing desorbed liquid discharged from the column body.

[0044] [Precipitation process] (carbon dioxide) In this embodiment, the carbon dioxide brought into contact with the liquid containing the desorbed ammonia in order to precipitate solid ammonia carbonate may be in the form of a gas, and / or a solution dissolved in a solvent, or a liquid at a pressure of 50 atmospheres or more. The case where carbon dioxide exists only in solid form, i.e., only dry ice, is excluded. For example, gaseous carbon dioxide includes pure carbon dioxide, a gas mixture containing carbon dioxide, and carbon dioxide in exhaust gas. Furthermore, the case includes the coexistence of gaseous and solid carbon dioxide, the coexistence of gaseous and the aforementioned liquid carbon dioxide, or the coexistence of gaseous, liquid, and solid carbon dioxide.

[0045] Methods for introducing carbon dioxide into the desorbed liquid include introducing carbon dioxide by bubbling or other methods, or spraying the desorbed liquid into a container where carbon dioxide is present. When the carbon dioxide is in liquid form, the desorbed liquid and carbon dioxide can be mixed in a pipe using a pump. In this embodiment, as described above, carbon dioxide can be brought into contact with the PB derivative while the eluent is in contact with it.

[0046] (Precipitation of ammonia carbonate) In this embodiment, the ammonia carbonates that precipitate in the liquid upon contact with carbon dioxide refer to ammonium bicarbonate, ammonium carbamate, ammonium sesquicarbonate, ammonium carbonate, and mixtures thereof, and also include impurities such as potassium ammonium carbonate and sodium ammonium carbonate due to the elution of components contained in the PB derivative. In this embodiment, the precipitation of ammonia carbonate is not limited to room temperature. For example, precipitation can also be carried out by contacting a liquid containing the desorbed ammonium with carbon dioxide and then maintaining it at a low temperature, or by applying an impact after maintaining it at a low temperature.

[0047] [Separation and Recovery Process] In this embodiment, the method for separating and recovering the ammonia carbonate precipitated in the desorbate upon contact with carbon dioxide is not particularly limited, but it can be easily recovered by sedimentation, flotation, filtration, centrifugation, or a combination thereof. Furthermore, as described in the previous section, when carbon dioxide is introduced while the PB derivative is in contact with the desorbed liquid, the precipitated ammonia carbonate and the PB derivative will coexist in the liquid. However, by using granulated PB derivative material and flowing the desorbed liquid, the precipitate can be separated by filter paper or mesh due to differences in size, or by sedimentation or buoyancy due to differences in buoyancy.

[0048] The separated carbonate can be used as a chemical raw material in the chemical industry, or as a fertilizer or neutralizing agent. Furthermore, by chemically converting the solid carbonate into ammonia, it can be used as an energy source for power generation or as a hydrogen carrier. Alternatively, useful substances derived from ammonia can be used as raw materials, such as pharmaceuticals, pesticides, surface treatment agents, amino acid and protein synthesis for food, and polymer synthesis for industrial use.

[0049] [Reuse of separated liquid] In this embodiment, after separating the carbonate precipitated in the liquid by introducing carbon dioxide, the separated liquid can be brought into contact with the PB derivative again and reused repeatedly.

[0050] [Recycling and reuse of PB derivatives] In the desorption process of this embodiment, the PB derivative from which the adsorbed ammonia has been desorbed has voids and spaces that can be used for further adsorption, so it can be recycled by adsorbing ammonia again and then desorbing it again.

[0051] Ammonia recovery device The ammonia recovery apparatus of this embodiment is The device includes an adsorbent installation section for installing an adsorbent made of a PB derivative, and an ammonia adsorption / desorption section for contacting the adsorbent, which has adsorbed ammonia, with an aqueous ammonium bicarbonate solution to desorb the adsorbed ammonia into the liquid, A solid precipitation unit that precipitates ammonia carbonate by introducing carbon dioxide into the desorbed liquid discharged from the adsorption / desorption unit, A solid-liquid separation unit separates the desorbed liquid containing solid ammonia carbonate discharged from the solid deposition unit into solid and liquid. It holds.

[0052] Furthermore, it is preferable that the ammonia recovery apparatus of this embodiment includes means for introducing the liquid remaining after the carbonate of the precipitated ammonia has been separated into the adsorption / desorption section, so that the desorbed liquid can be reused.

[0053] The ammonia recovery apparatus of this embodiment may be a batch system or a flow system.

[0054] Figure 4 illustrates an example of the ammonia recovery apparatus of this embodiment. In the figure, 1 represents the adsorbent installation section, 2 represents the ammonia adsorption / desorption section, 3 represents the solid precipitation section, 4 represents the solid-liquid separation section, 5 represents the carbon dioxide cylinder, and 6 represents the liquid transfer pump.

[0055] As shown in the figure, the ammonia adsorption / desorption unit 2 is equipped with an adsorbent installation unit 1 for installing an adsorbent made of a PB derivative, an ammonia gas inlet, an inlet for a desorption liquid consisting of an aqueous solution of ammonium bicarbonate or a mixture of an aqueous solution of ammonium bicarbonate and a water-soluble organic solvent, and an outlet for the desorption liquid containing ammonia desorbed from the adsorbent. Ammonia adsorbed on the adsorbent by the introduction of ammonia gas is desorbed into the desorption liquid by the introduction of the desorption liquid, and the desorption liquid containing ammonia desorbed from the adsorbent is discharged from the outlet.

[0056] The solid deposition unit 3 is equipped with a desorbed liquid inlet for introducing the desorbed liquid discharged from the adsorption / desorption unit 2, a carbon dioxide inlet, and an outlet for the desorbed liquid containing ammonia carbonate precipitated by the introduction of carbon dioxide. The desorbed liquid containing ammonia desorbed from the adsorbent, which is discharged from the adsorption / desorption unit 2, is introduced through the desorbed liquid inlet via the liquid transfer pump 6. At the same time, carbon dioxide from the carbon dioxide cylinder 5 is introduced into the desorbed liquid through the inlet, causing solid ammonium carbonate to precipitate.

[0057] The solid-liquid separation unit 4 includes an inlet for the desorbed liquid containing solid ammonia carbonate and an outlet for the desorbed liquid after the solid ammonia carbonate has been separated. The desorbed liquid containing solid ammonia carbonate precipitated in the solid precipitation unit 3 is introduced via the liquid transfer pump 6, and after solid-liquid separation, the desorbed liquid from which the solid ammonia carbonate has been separated is discharged from the outlet.

[0058] The desorbed liquid discharged from the solid-liquid separation unit 4 is introduced into the adsorption / desorption unit through an inlet provided in the desorption unit and reused to desorb ammonia adsorbed on the adsorbent.

[0059] In the apparatus of this embodiment, it is also conceivable to pressurize the space between the liquid transfer pumps 6 in order to increase the amount of dissolved carbon dioxide and thus increase the amount of precipitate. Furthermore, in the apparatus of this embodiment, when used as an apparatus for a flow system, the column shown in Figure 3 is used in the adsorbent installation section 1, and the desorption liquid is circulated through the column, thereby enabling continuous adsorption of ammonia onto the adsorbent, desorption of ammonia from the adsorbent, solid precipitation of ammonia carbonate from the desorption liquid, solid-liquid separation of the precipitated solid ammonia carbonate, and use of the separated liquid as a liquid for desorption of ammonia. [Examples]

[0060] Hereinafter, the present invention will be described by way of examples. However, the present invention is not limited to the following examples. All aspects using adsorbents within the scope of the technical idea of the present invention, as well as changes in materials, processing conditions, etc. are also included in the present invention.

[0061] [Example 1: Adsorption / Desorption Test of Ammonia (NH3) Using PB Derivative CuHCF] <Preparation of Cu2[Fe II (CN)6]> At room temperature, in a cylindrical plastic tube for centrifugation, an aqueous solution of copper(II) nitrate (CuSO4) was quickly mixed with an aqueous solution of K4[Fe(CN)6] at room temperature and stirred with a stirrer. The resulting compound was separated from the supernatant using a centrifuge, the supernatant was removed, and ultrapure water was added for shaking and washing. This was repeated three times to obtain a precipitate of copper-substituted Cu2[Fe II (CN)6] (hereinafter referred to as "CuHCF"). The obtained precipitate was formed and dried to obtain CuHCF granulates (cylindrical shape with a diameter of 5 mm and a length of 1 cm).

[0062] <Analysis of CuHCF>[[]] When the obtained CuHCF was evaluated using an X-ray diffractometer, the peak positions of this CuHCF were consistent with the peak positions of Fe[Fe(CN)6] in the database. From this, it was confirmed that the obtained CuHCF has the same crystal structure as the crystal structure of PB. Furthermore, approximately 50 mg of CuHCF powder was added to a mixed solution of 4 mL of hydrochloric acid and 2 mL of nitric acid, and the CuHCF powder was decomposed using a microwave decomposition apparatus. 0.75 After that, each element contained in CuHCF was quantified using an inductively coupled plasma mass spectrometer or an atomic emission spectrometer. In addition, C and N were quantified by a light element analysis method. As a result, the product was Cu2[Fe (CN)6]. II (CN)6].

[0063] <Adsorption / Desorption of Ammonia and Recovery of Solid NH4HCO3>[[]] Figure 5 shows the process of adsorption and desorption of ammonia (NH3) onto the CuHCF granules, and the recovery of solid NH4HCO3. Each process was carried out at room temperature and atmospheric pressure.

[0064] (NH3 adsorption) As shown in Figure 5, NH3 adsorption was performed by placing a 15 mL centrifuge tube containing approximately 1 g of granular CuHCF and a 50 mL centrifuge tube containing 40 mL of 28% NH3 solution into a 500 mL bottle and allowing them to stand for at least 48 hours. The NH3 concentration inside the bottle was measured at 60 vol% when the gas was diluted 10,000 times and detected using a detector tube.

[0065] (Desorption and separation of CuHCF) At 20°C, 21.6 g of ammonium bicarbonate (NH4HCO3) was dissolved in 100 mL of water to prepare a saturated NH4HCO3 aqueous solution. For desorption, approximately 1 g of adsorbed CuHCF granules and a saturated NH4HCO3 aqueous solution were placed in a 15 mL centrifuge tube with a liquid / solid ratio of 10, and shaken at 300 rpm for 48 hours using a shaker. After desorption, the granular CuHCF and supernatant were separated by centrifugation at 3000G for 10 minutes using a centrifuge. The supernatant after elimination was colored blue, indicating the presence of a copper ammine complex.

[0066] (Precipitation and recovery) To recover solid NH4HCO3, a mass flow controller was used to bubble carbon dioxide (CO2) into 4 mL of supernatant at a flow rate of 0.2 mL / min for 30 minutes, yielding the solid expected to be NH4HCO3. Figure 6 shows a photograph of the precipitates formed after CO2 injection. The supernatant was removed and the precipitated solid was collected. The recovered solid was identified using Fourier transform infrared spectroscopy (FTIR). Figure 7 shows the FTIR spectra of the precipitate obtained in Example 1 and commercially available ammonium bicarbonate (NH4HCO3). As shown in the figure, a spectrum similar to that of commercially available NH4HCO3 was obtained, confirming that NH3 can be recovered as solid NH4HCO3.

[0067] <Evaluation of material balance> The mass balance of NH3 involves eluting NH3 into an aqueous solution and dissolving NH4 in the solution. + The concentration was calculated from the results of ion chromatography (IC). First, the amount of NH3 adsorbed onto the CuHCF granules (Figure 5A, NH3 adsorption amount) was determined by washing the CuHCF granules with adsorbed NH3 three times with a 1M NaHSO4 solution with a liquid / solid ratio of 400. Furthermore, the amount of NH3 desorbed into the NH4HCO3 aqueous solution (Figure 5B, amount of NH3 desorbed) is equal to the amount of NH4 in a saturated NH4HCO3 aqueous solution. + Concentration and NH4 content of the eluent after desorption + Quantitative analysis was performed based on the difference in concentration. To determine the amount of NH3 remaining in the CuHCF granules after desorption (C in Figure 5, amount of NH3 in the adsorbent), the quantification was performed in several stages. First, to measure the mass of the dried adsorbent, the desorbed CuHCF granules were dried by blowing dry air at a flow rate of 100 mL / min for 24 hours. The discharged air was introduced into four impingers filled with 20 mL of 10 g / L Bolic solution to trap NH3. The amount of trapped NH3 was measured using ion chromatography. Next, the dried CuHCF granules were treated in the same manner as when A in Figure 5 was determined to determine the adsorption amount. C was calculated as the sum of the amount of NH3 trapped by the Bolic solution during drying and the amount of NH3 desorbed by washing with NaHSO4 aqueous solution after drying. These results are shown in Figure 8. Note that in Figure 8, the sum of B and C is not equal to A because of volatilization during the experiment. As can be seen from Figure 8, which shows the mass balances A, B, and C, approximately half of the NH3 adsorbed onto the CuHCF granules could be desorbed using an NH4HCO3 aqueous solution.

[0068] To determine the amount of precipitate (D) after blowing CO2 into the solution shown in Figure 5, the supernatant was removed using a pipette and dissolved in 4 mL of ultrapure water (milliQ® water). The precipitate was not dried as it was expected to be sublimable NH4HCO3. Figure 9 shows the balance of NH3 in the aqueous solution before and after CO2 injection, with the dotted line indicating the initial concentration of the eluent. In Figure 9, the fact that D is greater than B is because water evaporated when CO2 was injected. As can be seen in Figure 9, the NH3 that was removed in the NH4HCO3 aqueous solution was recovered as solid NH4HCO3 by blowing CO2 into it.

[0069] [Example 2] In Example 1, the concentration of ammonia water used to adsorb ammonia was changed to alter the concentration of ammonia gas adsorbed onto the adsorbent to 1.6 vol% and 0.096 vol%. Then, using these ammonia gases, an adsorption and desorption test of ammonia (NH3) using the PB derivative CuHCF was performed in the same manner as in Example 1. As a result, as shown in the table below, no solid precipitation was observed when the ammonia concentration in the adsorbed gas was 0.096 vol%. The results for Example 1 (60 vol%) are also shown in the table.

[0070] Ethanol was added to water to prepare aqueous solutions with ethanol concentrations of 30 vol%, 50 vol%, and 70 vol%. 3.27 g, 2.37 g, and 1.79 g of ammonium bicarbonate were dissolved in 30 mL of each solution, respectively. The NH4 contained in the resulting solutions was then analyzed. + When the concentrations were measured using IC, they were found to be 1.35 mol / L, 0.80 mol / L, and 0.39 mol / L, respectively. Using these solutions as desorption solutions, an adsorption and desorption test of ammonia (NH3) using the PB derivative CuHCF was performed in the same manner as in Example 1. As a result, it was confirmed that solid precipitation was observed even when the solution was replaced with a mixture of ethanol concentrations of 30 vol%, 50 vol%, and 70 vol%.

[0071] Furthermore, when the ethanol concentration in the eluent was 70 vol%, as shown in the table below, no solid precipitation was observed when the ammonia concentration in the adsorbed gas was approximately 0.096 vol% in the case where ethanol was not mixed (ethanol concentration 0 vol%). However, it was confirmed that solid precipitation was observed even when the ammonia concentration in the adsorbed gas was even lower, at 0.092 vol%. This indicates that mixing with ethanol reduces the solubility of ammonium bicarbonate, thereby promoting solid precipitation.

[0072] [Table 1]

[0073] [Example 3] <Preparation of adsorbent> In this example, in order to confirm that NH3 can be removed by saturated ammonium bicarbonate aqueous solution even at lower NH3 concentrations using PB derivatives other than CuHCF, seven types of PB derivatives listed in Table 2 were prepared in the same manner as the preparation example of CuHCF in Example 1.

[0074] [Table 2]

[0075] (Determination of NH3 adsorption and amount of NH3 adsorbed) Using the powders of each obtained PB derivative (hereinafter referred to as "samples"), the NH3 concentration during adsorption was changed from 60 vol% in Example 1 to 1.6 vol%, and NH3 adsorption was performed as follows. Each sample, approximately 300 mg, was placed in a petri dish, and a 100 ml beaker containing 100 ml of 2.8% ammonia water was left standing in a desiccator at atmospheric pressure and room temperature for 88 hours to allow NH3 adsorption. The NH3 concentration in the desiccator was measured with a detector tube and found to be 1.6 vol%. To quantify the amount of NH3 adsorbed onto each sample, approximately 20 mg of each sample, which had been left standing in the desiccator, was taken and washed three times with 10 ml of a 30 mmol / L NaHSO4 aqueous solution. The results are shown in Table 3.

[0076] (Desorption using NH4HCO3 solution and quantification of the desorbed NH3) Approximately 300 mg of each sample was placed in a saturated NH4HCO3 solution with a liquid / solid ratio of 5, shaken in the same manner as in Example 1, and then allowed to stand to separate the solid and liquid. After static separation, the amount of ammonia in each supernatant was quantified by IC, and the NH4 of the saturated NH4HCO3 aqueous solution was determined in the same manner as in Example 1. + It was calculated from the difference in concentration. The results are shown in Table 3. For the seven types listed in Table 3, it was shown that ammonia adsorbed with ammonium bicarbonate aqueous solution could be desorbed even at a lower NH3 concentration of 1.6 vol% compared to Example 1.

[0077] [Table 3]

[0078] (Introduction of CO2 into the eluent) The amount of detachment was the highest, In III [Fe III CO2 was introduced into the supernatant of (CN)6. III [Fe III When (CN)6] was shaken in a saturated NH4HCO3 solution and 4 mL of the supernatant after standing separation was bubbling carbon dioxide (CO2) at a flow rate of 0.2 mL / min for 60 minutes, NH4HCO3 precipitated, as in Example 1. Table 3 lists In III [Fe III For PB derivatives other than (CN)6, the NH4 in the elimination solution after elimination + Since the concentration will be higher than the saturation concentration of the NH4HCO3 aqueous solution, it is expected that NH4HCO3 will precipitate when carbon dioxide is brought into contact with the eluent solution after desorption.

[0079] [Example 4] In this embodiment, it was hypothesized that solid deposition would be facilitated by continuously performing the adsorption and desorption processes and increasing the ammonium ion concentration in the desorbed solution. Therefore, the adsorption and desorption processes were performed simultaneously and continuously, and it was confirmed that solid deposition was possible after increasing the amount of ammonia in the desorbed solution.

[0080] (Adsorption and desorption) CuHCF was synthesized and granules were prepared in the same manner as in Example 1. The obtained granules (74.42 g) were packed into the column body (5 cm × 5 cm × 5 cm) shown in Figure 3. Using a column packed with the CuHCF granules in the adsorbent installation section 1 of the apparatus shown in Figure 4, the adsorption of NH3 onto the PB derivative (granules) and the desorption of the adsorbed NH3 were performed simultaneously under the following conditions. NH3 was introduced by flowing 980 mL / min of air that had passed through 50°C water, and 20 mL / min of NH3 (NH3 concentration 2 vol%). The desorption solution used was an aqueous solution of ammonium bicarbonate at its saturated concentration at 7°C. This was carried out by circulating 250 mL of this aqueous solution at 130 mL / min and dripping it from above the column. Adsorption and desorption were carried out simultaneously and continuously, and carbon dioxide was brought into contact with the desorption solution at 0.3 MPa.

[0081] (Measurement of the amount of NH3 adsorbed on the column) Gas samples were collected from both sides of the column every hour, diluted 100-fold with air, and measured using a gas detection tube. The amount of NH3 adsorbed on the column was calculated from the difference in concentration before and after the sample. The results are shown as ■ in Figure 10.

[0082] (NH4 in the desorbed liquid) + (Measurement of concentration) One mL of the eluate discharged from the column was collected every hour and analyzed by ion chromatography (IC) for NH4 + The concentration was measured. The results are shown by ▲ in Figure 10. Figure 10 shows NH4 in the eluent. +The concentration initially decreases as ammonia from the desorbed liquid is incorporated into the adsorbent, but it gradually increases as adsorption and desorption continue.

[0083] (Precipitation of ammonium bicarbonate) After circulating the eluent for 30 hours, the eluent collected in the solid precipitate section 3 was placed in a container and left to stand in a refrigerator (the liquid temperature in the stored solution was 7°C). After standing overnight, the container was shaken and agitated, causing NH4HCO3 to precipitate. As can be seen in Figure 10, the precipitate was NH4 in the liquid. + This was because the concentration was higher than the saturation concentration at 7°C.

[0084] [Example 5] Although the PB derivative used in Example 3 could adsorb NH3 even at low NH3 concentrations, the amount of NH3 desorbed was small due to the low NH3 concentration. However, similar to Example 4, it was thought that continuous adsorption and desorption would facilitate solid precipitation, and this example was carried out accordingly. Instead of the CuHCF granules used in Example 4, one of the PB derivatives used in Example 3, Co II [Fe III (CN)6] 2 / 3 Granulated material was used, and an aqueous solution of ammonium bicarbonate prepared to a saturated concentration at 5°C was used as the desorbing liquid. Except for the changes to the granules and the desorption solution as described above, the process was the same as in Example 4, and the adsorption of NH3 onto the granules and the desorption of the adsorbed NH3 were carried out simultaneously and continuously, and the amount of NH3 adsorbed on the column and the amount of NH4 in the desorption solution were measured. + The concentration was measured. The results are shown in Figure 11. As indicated by the triangles in the figure, the amount of NH4 in the eluent increases over time. + The concentration increased. Also, NH4HCO3 precipitated in the solid precipitate section 3 18 hours after the start of the desorption process. Precipitation was observed in the liquid NH4 + This was because the concentration was higher than the saturation concentration of ammonium bicarbonate at room temperature (715 mmol of ammonia in the solution in the example shown in Figure 11). In this embodiment, it was demonstrated that the material can be recovered as a solid through simultaneous and continuous desorption without the need for operations such as cooling in a refrigerator or applying impact. [Industrial applicability]

[0085] According to the present invention, ammonia adsorbed on an adsorbent can be recovered inexpensively and efficiently as a solid carbonate, making it possible to use the present invention as a chemical raw material in the chemical industry, or as a fertilizer or neutralizing agent. Furthermore, by chemically converting the solid carbonate obtained by the present invention back into ammonia, it can be used as an energy source for power generation, as a hydrogen carrier, or as a useful substance derived from ammonia as a raw material, such as pharmaceuticals, pesticides, surface treatment agents, amino acid and protein synthesis for food, or polymer synthesis for industrial use. [Explanation of Symbols]

[0086] 1: Adsorbent installation part 2: Adsorption / desorption part 3: Solid precipitation part 4: Solid-liquid separation section 5: Carbon dioxide cylinder 6: Liquid transfer pump

Claims

1. A step of desorbing ammonia adsorbed onto a Prussian blue derivative represented by the following general formula (1) into the solution by contacting it with an aqueous solution of ammonium bicarbonate, A step of contacting a liquid containing the detached ammonia with carbon dioxide to precipitate solid ammonia carbonate, and The process of separating the precipitated ammonia carbonate from the ammonium bicarbonate aqueous solution. A method for recovering ammonia, including [the substance]. A ｘ M[M'(CN) ６ ] ｙ ・zH ２ O・・・(1) [In formula (1), x is a number from 0 to 3, y is a number from 0.1 to 1.5, z is a number from 0 to 6, A is a cation representing at least one or more combinations selected from the group consisting of hydrogen, ammonium cations, alkali metal ions, and alkaline earth metal ions, M and M' are each independently selected, M is a cation representing at least one or more combinations selected from the group consisting of atoms with atomic numbers 3 to 83 (excluding hydrogen, ammonium cations, alkali metal ions, and alkaline earth metal ions), and M' is at least one cation selected from the group consisting of atoms with atomic numbers 3 to 83 (excluding hydrogen, ammonium cations, alkali metal ions, and alkaline earth metal ions).]

2. The method for recovering ammonia according to claim 1, wherein in the desorption step, ammonia gas is brought into contact with a Prussian blue derivative represented by the general formula (1) and adsorbed.

3. The method for recovering ammonia according to claim 1, further comprising the step of using the liquid obtained after the separation of the ammonia carbonate as a liquid for desorbing ammonia adsorbed onto the Prussian blue derivative represented by the general formula (1).

4. The method for recovering ammonia according to claim 3, wherein in the desorption step, ammonia gas is brought into contact with a Prussian blue derivative represented by the general formula (1) and adsorbed.

5. The method for recovering ammonia according to any one of claims 1 to 4, wherein the aqueous solution of ammonium bicarbonate is a saturated aqueous solution of ammonium bicarbonate.

6. A method for recovering ammonia according to any one of claims 1 to 4, wherein, in the step of contacting the ammonium bicarbonate aqueous solution with the ammonia to desorb the ammonia into the liquid, a water-soluble organic solvent is added to the ammonium bicarbonate aqueous solution.

7. The method for recovering ammonia according to any one of claims 1 to 4, wherein the carbonate of the solid ammonia is ammonium bicarbonate.

8. The device includes an adsorbent installation section for installing an adsorbent made of a Prussian blue derivative represented by the following general formula (1), and an ammonia adsorption / desorption section for contacting the adsorbent, which has adsorbed ammonia, with an aqueous solution of ammonium bicarbonate to desorb the adsorbed ammonia into the liquid, A solid precipitation unit is provided in which carbon dioxide is introduced into the desorbed liquid discharged from the adsorption / desorption unit to precipitate ammonia carbonate, A solid-liquid separation unit separates the desorbed liquid containing solid ammonia carbonate discharged from the solid deposition unit into solid and liquid. An ammonia recovery device equipped with [a specific feature]. A ｘ M[M'(CN) ６ ] ｙ ・zH ２ O・・・(1) [In formula (1), x is a number from 0 to 3, y is a number from 0.1 to 1.5, z is a number from 0 to 6, A is a cation representing at least one or more combinations selected from the group consisting of hydrogen, ammonium cations, alkali metal ions, and alkaline earth metal ions, M and M' are each independently selected, M is a cation representing at least one or more combinations selected from the group consisting of atoms with atomic numbers 3 to 83 (excluding hydrogen, ammonium cations, alkali metal ions, and alkaline earth metal ions), and M' is at least one cation selected from the group consisting of atoms with atomic numbers 3 to 83 (excluding hydrogen, ammonium cations, alkali metal ions, and alkaline earth metal ions).]

9. The ammonia recovery apparatus according to claim 8, further comprising means for introducing the liquid obtained after the separation of the solid ammonia carbonate into the adsorption / desorption unit.

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