KR102510919B1 - Electrochemical ammonia synthesis method using nitrogen nanobubble sparger and electrochemical ammonia synthesis apparatus - Google Patents

Abstract

The present invention relates to an electrochemical ammonia synthesis method and an electrochemical ammonia synthesis apparatus using a nitrogen nanobubble sparger, and more particularly, by supplying an appropriate amount of nitrogen nanobubbles from a nitrogen nanobubble sparger spaced apart from a reduction electrode at regular intervals. By accelerating the physical and chemical adsorption and absorption behavior of nitrogen atoms at the interface of the cathode, the synthesis yield and current efficiency of ammonia can be remarkably improved through an active nitrogen reduction reaction with hydrogen ions. In addition, since it is performed at room temperature and pressure, equipment and processes are simple, and the generated ammonia is dissolved in an aqueous solution in the form of NH ₄ ⁺ ions, so there are advantages of excellent stability.

Description

Electrochemical ammonia synthesis method using nitrogen nanobubble sparger and electrochemical ammonia synthesis apparatus

The present invention relates to an electrochemical ammonia synthesis method and an electrochemical ammonia synthesis apparatus using a nitrogen nanobubble sparger.

The Harbor-bosh method, which is most often used to synthesize ammonia, proceeds by reacting nitrogen and hydrogen under high temperature and high pressure under an iron (Fe) catalyst. Since the bond energy of the nitrogen-nitrogen triple bond (N≡N) is very high compared to other bonds, a lot of energy is required to break the bond between nitrogen and synthesize ammonia. Fossil fuels used for supplying such energy have a problem of emitting a large amount of greenhouse gases of 1.8 ton CO ₂ /ton NH ₃ .

In order to overcome the problems of the Haber-Bosch process, an electrochemical ammonia synthesis method using an ion conductive oxide electrolyte has been proposed, and research on an electrochemical ammonia synthesis method using an electrolyte using water and nitrogen as raw materials has been actively conducted. However, it is known that the solubility of reactants in the gaseous state is very low at room temperature and pressure. In particular, in the case of nitrogen gas, its solubility in an aqueous solution such as water is about twice as high as that of oxygen, CO, or CO ₂ gas, so the solubility of nitrogen, the first reactant in the synthesis of ammonia, is poor, and nitrogen molecules are transferred to the catalyst electrode interface. There is a problem with this not working properly.

In order to solve this problem, it is required to use a very expensive ionic liquid electrolyte or to pressurize the reactor itself to a very high level, but this causes a price increase due to equipment and operation of the process and has a problem of poor synthesis stability . Another method is to increase ammonia synthesis efficiency by using Li metal ions as a medium in an organic electrolyte. This is a method of increasing the reduction reaction of nitrogen by nitriding nitrogen gas through the reducing power of lithium metal to selectively break the triple bond (N≡N) of nitrogen molecules.

However, these existing methods are insufficient as a fundamental solution because they do not identify a method for increasing the solubility of nitrogen gas itself or a clear mechanism for physicochemical behavior and mass transfer. In addition, in order to utilize the Li mediator, it is necessary to go through a separate three-step process of depositing Li metal on the interface of the catalyst electrode, performing nitridation (Li ₃ N) through nitrogen gas injection, and performing ammonia synthesis through an electrochemical reduction reaction. Therefore, there is a limitation that a continuous process cannot be performed in one reactor.

Korean Patent Registration No. 10-2154282

In order to solve the above problems, an object of the present invention is to provide an electrochemical ammonia synthesis method using a nitrogen nanobubble sparger with significantly improved ammonia synthesis yield.

Another object of the present invention is to provide an electrochemical ammonia synthesizer including a nitrogen nanobubble sparger.

The present invention is an electrochemical ammonia synthesis method using a nitrogen nanobubble sparger, wherein the method includes electrons (e ^- ), hydrogen ions (H ⁺ ) and Generating oxygen gas (O ₂ ); passing the hydrogen ions through a proton exchange membrane (PEM) or separation membrane positioned between the anode and cathode; and producing ammonia gas (NH ₃ gas) or ammonium ions (NH ₄ ⁺ ) by allowing hydrogen ions passing through the proton exchange membrane or membrane to reach a cathode portion including a cathode, a cathode solution, and nitrogen nanobubbles; wherein the cathode solution contains an alkali metal ion additive, and the nitrogen nanobubbles are supplied from a nitrogen nanobubble sparger spaced apart from the cathode at a distance of 1 to 10 mm. A synthetic method is provided.

In addition, the present invention is a reaction chamber; a cathode unit located inside the reaction chamber and including a cathode and a cathode solution; a nitrogen nanobubble sparger located at a distance of 1 to 10 mm from the cathode inside the reaction chamber; a nitrogen nanobubble generator connected to the nitrogen nanobubble sparger and positioned outside the reaction chamber; an anode unit located inside the reaction chamber and including an anode and an anode electrode solution; and a proton exchange membrane or separation membrane positioned between the cathode and anode portions.

The electrochemical ammonia synthesis method according to the present invention supplies an appropriate amount of nitrogen nanobubbles from a nitrogen nanobubble sparger spaced apart from the reduction electrode at regular intervals to promote the physical and chemical adsorption and absorption behavior of nitrogen atoms at the interface of the reduction electrode, thereby catalyzing the catalyst. The active reduction of hydrogen ions and nitrogen on the electrode reaction surface can significantly improve the synthesis yield and current efficiency of ammonia.

In addition, the electrochemical ammonia synthesis method according to the present invention is carried out at room temperature and pressure, so the equipment and process are simple, and the generated ammonia is dissolved in aqueous solution in the form of ammonium ions of NH ₄ ⁺ according to the pH operating conditions, so it has excellent stability. there is

The effects of the present invention are not limited to the effects mentioned above. It should be understood that the effects of the present invention include all effects that can be inferred from the following description.

1 is a reaction schematic diagram of a multi-electrode single-step electrochemical ammonia synthesis method according to the present invention.
Figure 2 schematically shows the electrochemical ammonia synthesis process at the cathode according to the present invention.
3 shows an electrochemical ammonia synthesizer according to the present invention.
4 shows changes in the generation behavior of nitrogen nanobubbles supplied from the nitrogen nanobubble sparger of the electrochemical ammonia synthesizer according to the present invention.

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

The present invention relates to an electrochemical ammonia synthesis method and an electrochemical ammonia synthesis apparatus using a nitrogen nanobubble sparger.

As described above, the Haber-Bosch method for producing ammonia requires a lot of energy by reacting nitrogen and hydrogen at high temperature and high pressure under an iron catalyst. In order to improve this, there are existing methods of using expensive ionic liquid electrolytes or Li metal ion mediators, but there are disadvantages of price increase due to process equipment and operation and a separate three-step process for ammonia synthesis there is.

Therefore, the electrochemical ammonia synthesis method of the present invention supplies an appropriate amount of nitrogen nanobubbles from a nitrogen nanobubble sparger spaced apart from the cathode at regular intervals, thereby physically and chemically adsorbing and absorbing nitrogen atoms at the interface of the cathode through a single continuous process. It is possible to remarkably improve the synthesis yield and current efficiency of ammonia by promoting active nitrogen reduction reaction through hydrogen ion and hydrogenation reaction by promoting the behavior.

In addition, since it is performed at room temperature and pressure, equipment and processes are simple, and the generated ammonia is dissolved in an aqueous solution in the form of NH ₄ ⁺ ions, so there are advantages of excellent stability. In addition, the supply of nitrogen nanobubbles can maximize the solubility of nitrogen gas in acidic, neutral, basic and organic electrolytes, thereby improving the yield of ammonia synthesis. The produced ammonia water is weakly alkaline and has the advantage of being applicable as an on-site nitrogen fertilizer reactor for agriculture.

Specifically, the present invention is an electrochemical ammonia synthesis method using a nitrogen nanobubble sparger, wherein the method includes electrons (e ^- ), hydrogen ions (H ⁺ ) and generating oxygen gas (O ₂ ); passing the hydrogen ions through a proton exchange membrane (PEM) or separation membrane positioned between the anode and cathode; and producing ammonia gas (NH ₃ gas) or ammonium ions (NH ₄ ⁺ ) by allowing hydrogen ions passing through the proton exchange membrane or membrane to reach a cathode portion including a cathode, a cathode solution, and nitrogen nanobubbles; wherein the cathode solution contains an alkali metal ion additive, and the nitrogen nanobubbles are supplied from a nitrogen nanobubble sparger spaced apart from the cathode at a distance of 1 to 10 mm. A synthetic method is provided.

1 is a reaction schematic diagram of a multi-electrode single-step electrochemical ammonia synthesis method according to the present invention. Referring to FIG. 1, as water is decomposed on the surface of the anode, hydrogen ions are generated, and the generated hydrogen ions pass through the cation conductive membrane to reach the cathode. It is shown that nitrogen nanobubbles supplied from the nitrogen nanobubble sparger exist on the surface of the reduction electrode, and the nitrogen nanobubbles are reduced by the hydrogen ions and electrons to be synthesized into ammonia. The ammonia synthesis method of the present invention is simple compared to conventional synthesis methods because this process is performed in a single step, and ammonia can be synthesized with only a simple device because it is performed at room temperature and pressure.

Figure 2 schematically shows the electrochemical ammonia synthesis process at the cathode according to the present invention. Referring to FIG. 2, a nitrogen nanobubble generator located outside the reaction chamber is connected to a nitrogen nanobubble sparger, and the nitrogen nanobubble sparger reduces nitrogen nanobubbles at a position spaced apart from the reduction electrode at regular intervals. It is supplied to the interface of the electrode. Hydrogen ions, electrons, and alkali metal ion additives are present on the surface of the cathode, and it is shown that they generate ammonia by a reduction reaction with nitrogen nanobubbles.

In the step of generating electrons and hydrogen ions, the anode portion refers to a compartment in which hydrogen ions are generated, and may include the anode and the electrode solution. The oxidation electrode solution may include a hydrogen ion donor, an ion transport material, or a mixture thereof. The hydrogen ion donor may be at least one selected from the group consisting of water, hydrogen, hydrogen sulfide, methane, alcohol, and seawater, and preferably water. In addition, the ion transport material may be at least one selected from the group consisting of an aqueous solution of sulfuric acid, an aqueous solution of nitric acid, an aqueous solution of hydrochloric acid, an aqueous solution of lithium chloride, an aqueous solution of lithium sulfate, an aqueous solution of sodium sulfate, and an aqueous solution of lithium perchlorate. Preferably, it may be an aqueous solution of lithium sulfate and an aqueous solution of sodium sulfate, or a mixture thereof, and most preferably an aqueous solution of sodium sulfate.

In the step of generating electrons and hydrogen ions, electrons and hydrogen ions may be generated by decomposing water on the surface of the anode of the anode portion including the anode and the anode solution. In this case, the anode may include at least one metal selected from the group consisting of Ir, Pt, Ti, and Ni, and a catalyst, preferably a mesh-shaped Ir/Ti alloy or Pt/Ti alloy, and the most Preferably, it may be a Pt/Ti alloy in the form of a mesh.

The proton exchange membrane or separation membrane may serve to separate the anode portion and the cathode portion, and enable the movement of hydrogen ions generated from the anode portion. The proton exchange membrane or separation membrane is porous, and a polymer membrane into which a sulfonic acid group, a phosphoric acid group or a carboxyl group is introduced, such as a perfluorine-based sulfonated ionomer, a hydrocarbon-based polymer membrane, or a sulfonated polyether ether ketone (SPEEK) polymer containing imidazole or It may be a polymer film doped with pyrazole, preferably a hydrocarbon-based polymer film.

In the step of producing ammonia gas (NH ₃ gas) or ammonium ion (NH ₄ ⁺ ), ammonia production gas may be synthesized by reducing nitrogen nanobubbles with hydrogen ions and electrons at the reduction electrode of the reduction electrode unit. The cathode part is in contact with a proton exchange membrane or a separator, and includes a cathode, a cathode solution, and nitrogen nanobubbles, and hydrogen ions supplied through the cation conductive membrane undergo a reduction reaction with the cathode solution and nitrogen nanobubbles on the surface of the cathode. It may be a location where ammonia production gas is synthesized.

The reduction electrode can be used as an electrode as it is with the entire positive electrode obtained from the waste lithium ion battery. Preferably, the cathode is in the form of foam, mesh, felt, or woven, and is relatively inexpensive Ni, Mo, Fe, Co, Ni, Zn, Au instead of expensive precious metals. , Bi and at least one conductive metal selected from the group consisting of Ti and a catalyst. In this case, the conductive metal may be a single metal, an alloy, or a metal-metal oxide composite. More preferably, the cathode may be nickel foam or iron foam, most preferably nickel foam.

The catalyst of the reduction electrode is V, Cr. It may be at least one selected from the group consisting of Mn, Fe, Co, Ni, Cu, Nb, Mo, Ru, Rh, Pd, Ag, Au, and Bi.

The cathode solution may include an alkali metal ion additive. The alkali metal ion additive may be mixed to increase the selectivity of the ammonia production reaction by improving the ammonia synthesis reaction and increasing the nitration reaction of nitrogen gas to minimize the competing reaction, the hydrogen generation reaction. The alkali metal ion additive may be at least one selected from the group consisting of LiClO ₄ , Li ₂ SO ₄ , LiOH, and LiF, which is stable and soluble in water, and is preferably LiClO ₄ , Li ₂ SO ₄ or a mixture thereof. , and most preferably LiClO ₄ .

The cathode solution may further include an alkali electrolyte, and the alkali electrolyte may selectively produce only ammonia gas (NH ₃ ) by adjusting pH. The alkaline electrolyte may be KOH or NaOH. Also, if necessary, the alkaline electrolyte may be a mixture of at least one electrolyte having a neutral and slightly acidic pH selected from the group consisting of Na ₂ SO ₄ , PBS, K ₂ SO ₄ , NaSO ₃ and KCl.

The nitrogen nanobubbles may be supplied from a nitrogen nanobubble sparger spaced apart from the cathode part at an interval of 1 to 10 mm, preferably 1 to 5 mm, and most preferably 1 to 3 mm. At this time, if the distance between the cathode part and the nitrogen nanobubble sparger is less than 1 mm, too many nitrogen nanobubbles exist on the surface of the cathode, which may interfere with the synthesis of ammonia. Conversely, if the thickness exceeds 10 mm, mass transfer of nitrogen nanobubbles to the surface of the cathode is not effectively performed, and thus the synthesis yield of ammonia may gradually decrease.

The nitrogen nanobubble sparger generates nitrogen gas in the form of nitrogen nanobubbles having an average particle diameter of 200 nm to 800 nm in order to maximize the solubility of nitrogen gas to maximize the self-pressurization effect of nitrogen gas, thereby increasing the solubility and retention time of the gas. By increasing the nitrogen gas mass transfer to the cathode interface can be significantly improved. Here, the self-pressurization effect refers to an effect that occurs due to the force of compressing the gas by the surface tension inside the bubble having a spherical interface. In addition, the nitrogen nanobubble sparger can advantageously lead the ammonia equilibrium on the surface of the cathode to the ammonia production reaction by effectively dissolving the generated ammonia ions in the electrolyte solution.

The nitrogen nanobubbles have a higher energy level than nitrogen gas, so that an activation reaction is improved, thereby improving nitration with the alkali metal ion additive. In addition, compared to the existing ammonia synthesis method using Li metal ion as a medium, the nitrogen nanobubbles are formed to deposit the interface of the cathode with the alkali metal ion additive in one reactor, the nitration reaction of the alkali metal ion additive and nitrogen gas molecules, and the nitrification The hydrogenation reaction of lithium metal and hydrogen atoms can occur simultaneously.

The nitrogen nanobubbles may have an average particle diameter of more preferably 200 to 800 nm, and most preferably 400 to 600 nm. At this time, if the average particle diameter of the nitrogen nanobubbles is less than 200 nm, the bubble size is too small and the bubbles aggregate with each other to prevent proper ammonia synthesis or to continuously impair physical stability of the pump due to the formation of gas cavities due to the nanobubbles. Conversely, if the average particle diameter of the nitrogen nanobubbles exceeds 200 nm, the effect of the bubble sparger cannot be expected.

The nitrogen nanobubbles are injected from the nitrogen nanobubble sparger to the surface of the cathode at an injection amount of 5 to 100 cc, preferably 10 to 80 cc, more preferably 10 to 50 cc, and most preferably 10 to 30 cc it may be At this time, if the injection amount of the nitrogen nanobubbles is less than 5 cc, the yield of synthesizing ammonia-producing gas on the surface of the reduction electrode may be remarkably low, and conversely, if the injection amount exceeds 100 cc, unreacted nitrogen nanobubbles may interfere with ammonia synthesis. there is. In addition, when injecting the nitrogen nanobubbles, the injection pressure of the nitrogen nanobubbles is preferably maintained at 2 to 5 bar, preferably 2 to 3 bar, and most preferably 2.5 bar, depending on the injection gas flow rate and the electrolyte circulation rate.

The step of producing the ammonia gas (NH ₃ gas) or ammonium ion (NH ₄ ⁺ ) may be performed for 2 to 10 hours in the case of a circulation type depending on the concentration and amount of the electrolyte, and continuously maintain the concentration of the electrolyte In some cases, it can be performed for more than 10 hours. Preferably, it can be carried out for 2 to 6 hours at room temperature and normal pressure conditions. The room temperature may be a low temperature of 100 °C or less, and the normal pressure may be a low pressure of 10 bar or less.

In the step of producing the ammonia gas (NH ₃ gas) or ammonium ion (NH ₄ ⁺ ), the concentration of ammonia may vary depending on operating conditions such as the size of the electrode and the number of electrodes used, and based on a single electrode of 30 cm ² Ammonia production of 2 to 10 ppm/hr, preferably 2 to 5 ppm/hr, may be possible.

In particular, although not explicitly described in the following Examples or Comparative Examples, in the electrochemical ammonia synthesis method according to the present invention, ammonia was synthesized by varying the following 9 conditions, respectively, and the ammonia synthesis concentration by a conventional method and long-term stability.

As a result, unlike other conditions and other numerical ranges, it was confirmed that the synthesis concentration of ammonia produced was synthesized at a very high level of 5 ppm/hr or more when all of the conditions below were satisfied, and the ammonia concentration remained at a certain level for a long period of time. It was confirmed that the storage stability was excellent.

① the anode is a Pt/Ti alloy in the form of a mesh, ② the anode solution contains an aqueous sodium sulfate solution, ③ the cathode is a nickel foam, ④ the alkali metal ion additive is LiClO ₄ , and ⑤ the nitrogen nano The bubbles have an average particle diameter of 400 to 600 nm, ⑥ the nitrogen nanobubbles are injected from the nitrogen nanobubble sparger to the surface of the cathode at an injection amount of 10 to 30 cc under an injection pressure of 2 to 3 bar, ⑦ the nitrogen nanobubbles Bubbles are supplied from a nitrogen nanobubble sparger spaced apart from the cathode at a distance of 1 to 3 mm, and ⑧ the step of producing ammonia gas (NH ₃ gas) or ammonium ion (NH ₄ ⁺ ) is performed at room temperature and It is carried out for 2 hours to 6 hours under normal pressure conditions, and ⑨ the concentration of ammonia in the ammonia production gas may be 2 to 5 ppm/hr based on a single electrode of 30 cm ² .

However, when any of the above 9 conditions was not met, the synthesis yield of ammonia was significantly lower than 1 ppm/hr, and the synthesis rate and yield of ammonia rapidly increased after 24 hours. has been lowered

On the other hand, the present invention is a reaction chamber; a cathode unit located inside the reaction chamber and including a cathode and a cathode solution; a nitrogen nanobubble sparger located at a distance of 1 to 10 mm from the cathode inside the reaction chamber; a nitrogen nanobubble generator connected to the nitrogen nanobubble sparger and positioned outside the reaction chamber; an anode unit located inside the reaction chamber and including an anode and an anode electrode solution; and a proton exchange membrane or separation membrane positioned between the cathode and anode portions.

a water supply unit supplying water to the anode unit in the reaction chamber; and an oxygen recovery unit that recovers oxygen generated by electrolysis of water from the anode unit.

An ammonia concentration measuring unit connected to the reduction electrode in the reaction chamber and positioned outside the reaction chamber to measure the generated ammonia concentration; may further include.

3 shows an electrochemical ammonia synthesizer according to the present invention. Referring to FIG. 3, it is shown that a nitrogen nanobubble generator is located outside the reaction chamber, and a nitrogen nanobubble sparger connected to the nitrogen nanobubble generator is spaced apart from the reduction electrode at regular intervals. In addition, it shows that the ammonia concentration measuring unit for measuring the ammonia concentration is located outside the reaction chamber.

4 shows changes in the generation behavior of nitrogen nanobubbles supplied from the nitrogen nanobubble sparger of the electrochemical ammonia synthesizer according to the present invention. Referring to FIG. 4, it is shown that nitrogen nanobubbles are generated by controlling an injection amount of nitrogen of 10 to 30 cc and a pressure of 2.5 bar.

Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited by the following examples.

Example 1: Electrochemical synthesis of ammonia using a nitrogen nanobubble sparger

Ammonia synthesis was performed according to the ammonia synthesis method shown in FIG. 1 for electrochemical ammonia synthesis using the nitrogen nanobubble sparger of the present invention. A mesh-type Pt/Ti alloy in which Pt was electrochemically deposited was used as an anode in the reactor, and a Ni foam having a total area of 30 cm ² was used as a cathode. In addition, 0.1 M Na ₂ SO ₄ was used as the oxidizing electrode solution, and 0.05 M LiClO ₄ was used as the reducing electrode solution. At this time, when a membrane or a diaphragm is used, an aqueous solution in which water or a weakly acidic material such as 0.1 to 0.5 MH ₂ SO ₄ is mixed may be used as the oxidizing electrode solution.

The nitrogen nanobubble sparger was spaced apart from the cathode at a distance of 3 mm, and nitrogen nanobubbles having an average particle diameter of 500 nm were supplied in the reactor at an injection amount of 20 cc. Ammonia synthesis was carried out for 1 hour or more using a method in which an electrochemical reduction voltage was applied in an atmosphere in which nitrogen gas was sufficiently injected for 30 minutes or more at room temperature and pressure conditions, and the ammonia concentration obtained for more than several hours was measured.

The synthetic concentration of the obtained ammonia was measured using the indophenol blue method using ^an indophenol indicator and a UV-vis optical meter _. For accurate measurement, cation chromatography (IC) and ¹ H The synthesized concentration of ammonia was verified by measuring ¹⁵ NH ₄₊ ions by ^NMR (nuclear magnetic resonance spectrometry).

Through this, it was confirmed that ammonia was synthesized at a concentration of about 2 to 5 ppm/hr. It was found that these results are significantly improved compared to the results of tens to hundreds of ppb/hr or less of ammonia produced by the existing three-step electrochemical ammonia synthesis process. In addition, by designing a multi-electrode reactor, it was possible to guess that a more increased and concentrated ammonia synthesis rate and high current efficiency could be obtained in one reactor by easily increasing the number of electrodes.

Claims (11)

As an electrochemical ammonia synthesis method using a nitrogen nanobubble sparger,
The method includes generating electrons (e ⁻ ), hydrogen ions (H ⁺ ), and oxygen gas (O ₂ ) in an anode portion containing an anode and an anode solution or water;
passing the hydrogen ions through a proton exchange membrane (PEM) or separation membrane positioned between the anode and cathode; and
Producing ammonia gas (NH ₃ gas) or ammonium ion (NH ₄ ⁺ ) by reaching a cathode portion including a cathode, a cathode solution, and nitrogen nanobubbles in which hydrogen ions passing through the proton exchange membrane or separation membrane are produced. include,
The anode is a Pt/Ti alloy in the form of a mesh,
The oxidizing electrode solution includes an aqueous solution of sodium sulfate,
The cathode is nickel foam,
The cathode solution contains an alkali metal ion additive,
The alkali metal ion additive is LiClO ₄ ,
The nitrogen nanobubbles have an average particle diameter of 400 to 600 nm,
The nitrogen nanobubbles are supplied from a nitrogen nanobubble sparger spaced apart from the cathode at an interval of 1 to 3 mm,
The nitrogen nanobubbles are injected from the nitrogen nanobubble sparger to the surface of the cathode at an injection amount of 10 to 30 cc under an injection pressure of 2 to 3 bar,
The step of producing the ammonia gas (NH ₃ gas) or ammonium ion (NH ₄ ⁺ ) is performed for 2 to 6 hours at room temperature and pressure conditions,
The concentration of ammonia in the ammonia gas is 2 to 5 ppm / hr based on a single electrode of 30 cm ² Electrochemical ammonia synthesis method.
delete delete delete delete delete delete delete reaction chamber;
a cathode unit located inside the reaction chamber and including a cathode and a cathode solution;
a nitrogen nanobubble sparger located at a distance of 1 to 3 mm from the cathode inside the reaction chamber;
a nitrogen nanobubble generator connected to the nitrogen nanobubble sparger and positioned outside the reaction chamber;
an anode unit located inside the reaction chamber and including an anode and an anode electrode solution; and
a proton exchange membrane or separation membrane positioned between the cathode and anode portions;
including,
The anode is a Pt/Ti alloy in the form of a mesh,
The oxidizing electrode solution includes an aqueous solution of sodium sulfate,
The cathode is nickel foam,
The cathode solution contains an alkali metal ion additive,
The alkali metal ion additive is LiClO ₄ ,
The nitrogen nanobubbles have an average particle diameter of 400 to 600 nm,
The nitrogen nanobubbles are supplied from a nitrogen nanobubble sparger spaced apart from the cathode at a distance of 1 to 3 mm,
The nitrogen nanobubbles are injected from the nitrogen nanobubble sparger to the surface of the cathode at an injection amount of 10 to 30 cc under an injection pressure of 2 to 3 bar,
Hydrogen ions (H ⁺ ) generated at the anode portion pass through the proton exchange membrane or separation membrane and then reach the cathode portion to generate ammonia gas (NH 3 gas) or ammonium ions (NH ₃ gas) or ammonium ions ( NH ₄ ⁺ ) is produced,
The concentration of ammonia in the ammonia gas is 2 to 5 ppm / hr based on a single electrode of 30 cm ² Electrochemical ammonia synthesizer.
According to claim 9,
a water supply unit supplying water to the anode unit in the reaction chamber; and
Electrochemical ammonia synthesizer further comprising an oxygen recovery unit for recovering oxygen generated by electrolysis of water from the anode unit.
According to claim 9,
An ammonia concentration measuring unit connected to the reduction electrode in the reaction chamber and located outside the reaction chamber to measure the generated ammonia concentration; electrochemical ammonia synthesis apparatus further comprising.

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