Adsorbent for low-temperature helium-neon separation and preparation method thereof

Abstract

The invention relates to an adsorbent for low-temperature helium-neon separation and a preparation method thereof. The adsorbent disclosed by the invention is prepared by carrying out a rapid carbonization process in a high-temperature field of a plasma reactor after carrying out ultrasonic atomization on a mixed solution of cane sugar and an auxiliary agent. According to the method, metal co-doping atomic-scale uniform dispersion is realized in a high-temperature field of a plasma reactor by adding metal sources (nitrate and sulfate) into an atomized solution. Compared with a carbon material prepared by a traditional hydrothermal method, the carbon-based adsorbent prepared by the method has a smaller microscopic size and a higher specific surface area, overcomes the technical defects of the existing hydrothermal method, and provides a method for preparing the carbon-based adsorbent by using a plasma high-temperature field. According to the preparation method, rapid carbonization, graphitization and functionalization integration of cane sugar can be realized within millisecond-second-level time.

Description

Technical Field

[0001] This invention belongs to the field of adsorbent preparation technology, specifically an adsorbent for low-temperature helium-neon separation and its preparation method. Background Technology

[0002] High-purity helium has wide applications in semiconductors, medical fields, military industry, aerospace, and other fields, and is one of the rare strategic materials indispensable for the development of high-tech industries. my country's helium industry, based on imported natural gas BOG (Boiled Gas from Gas) sources, can purify helium to 5N to 6N or higher. However, my country's proven helium reserves account for only 2% of the world's reserves, and the helium content in my country's natural gas is very low, averaging only 0.04%. The neon content is also higher in China than in foreign sources. During helium purification and concentration, trace amounts of neon are also concentrated, resulting in the purified helium products often containing several to tens of ppm of neon impurities, making it difficult to obtain high-purity or ultra-pure helium with a purity of 6N or higher.

[0003] Because helium and neon have very similar physicochemical properties, existing gas separation technologies such as cryogenic distillation, membrane separation, and pressure swing adsorption (PSA) struggle to efficiently remove trace amounts of neon from helium. Theoretically, under cryogenic conditions, the difference in adsorption capacity between helium and neon on a highly efficient adsorbent could remove trace amounts of neon from helium. However, this method places high demands on the adsorbent, requiring not only a high neon adsorption capacity but also a high separation coefficient between helium and neon to prevent high helium loss during regeneration and thus significant waste of helium resources.

[0004] Patent CN119633756B discloses a porous adsorbent material for removing neon from helium and its preparation method. The method uses fermented lignin as raw material, which is carbonized, impregnated with metal salts and surfactants, dried, and washed to obtain a precursor. Finally, the adsorbent material is obtained through high-temperature carbon dioxide activation. This method uses fermented biomass raw materials, which has drawbacks such as a long cycle and unstable composition. Its highest neon adsorption capacity at 77K and 0.1kPa is 0.0064 mmol / g (0.14 mL / g), indicating poor neon adsorption performance.

[0005] Patent CN119750510A discloses a MOF material for helium-neon separation, using 2,5-dihydroxy-1,4-benzoquinone as a ligand, with the metal ion selected from one or more of iron, manganese, and zirconium ions. Its neon adsorption capacity at 77 kJ and 100 kPa is 92 mL / g. Although MOF materials exhibit high adsorption capacity, their currently high cost and poor stability limit their widespread application in industrial plants.

[0006] Carbon materials possess advantages such as abundant pore structures and ease of control, making them a promising adsorbent material. However, carbon materials obtained through direct hydrothermal carbonization suffer from drawbacks such as low specific surface area and underdeveloped pore structures. Therefore, a carbon-based adsorbent capable of efficiently separating helium and neon under low-temperature conditions has become a current research focus. In the field of BOG helium extraction technology, several technical solutions exist. For example, our patent application CN115155257B, "A Method for Extracting High-Purity Helium from Low-Helium-Containing BOG," discloses a system and method for extracting high-purity helium from low-helium-containing BOG. ​​This method comprehensively utilizes multiple processes such as membrane separation, pressure swing adsorption, and cryogenic adsorption to achieve the extraction of high-purity helium from low-helium-containing BOG, solving the problems of high investment and high energy consumption in existing cryogenic distillation processes for helium separation. Our patent CN117753170A, "A Low-Temperature Pressure Swing Adsorption Method for Efficiently Removing Neon and Hydrogen from Helium," discloses a low-temperature pressure swing adsorption method for efficiently removing neon and hydrogen from helium. The product obtained from the non-adsorbed phase has a low helium impurity content, with a neon volume concentration of less than 4 ppm and a hydrogen volume concentration of less than 1 ppm; furthermore, this method has a low helium loss rate. Our existing process patents all use commercially available activated carbon adsorbents to treat neon impurities, resulting in a low neon adsorption capacity and impacting the processing efficiency of the process. Summary of the Invention

[0007] The purpose of this invention is to address the problems of small specific surface area and uneven pore distribution of carbon materials in existing technologies. This patent develops a special adsorbent for the adsorption and removal of neon, and, in conjunction with the company's existing process patents, solves the problem of efficient separation of helium from helium-containing industrial tail gas. A method for preparing a (carbon-based) adsorbent for low-temperature helium-neon separation has been developed. This method can achieve rapid carbonization and graphitization, and effectively control the micro-size and pore structure of the material, thereby improving the performance of the prepared adsorbent in separating and adsorbing helium and neon under low-temperature conditions.

[0008] To achieve the above-mentioned objectives, the specific technical solution of the present invention is as follows: A method for preparing a (carbon-based) adsorbent for low-temperature helium-neon separation, wherein the adsorbent uses a mixed solution of sucrose and a metal source (and water) as the main synthetic raw material. The mixed solution is ultrasonically atomized and then carried into the high-temperature field of a plasma reactor by a carrier gas for rapid carbonization. After water cooling, the carbon sphere powder co-doped with heteroatoms is collected. The carbon sphere powder is then uniformly mixed with an appropriate amount of binder, extruded into strips, and calcined in a tubular converter at a certain temperature for a certain time to finally obtain the carbon-based adsorbent for low-temperature helium-neon separation.

[0009] In a preferred embodiment of this application, the metal source in the preparation step is one of magnesium nitrate, magnesium sulfate, ferric nitrate, ferric sulfate, copper nitrate, copper sulfate, zinc nitrate, zinc sulfate, chromium nitrate, chromium sulfate, cobalt nitrate, cobalt sulfate, nickel nitrate, nickel sulfate, manganese nitrate, manganese sulfate, lanthanum nitrate, lanthanum sulfate, cerium nitrate, and cerium sulfate.

[0010] As a preferred embodiment of this application, the mass ratio of the metal source in the preparation step is 1 to 30 (here referring to the mass ratio of sucrose to the metal source, specifically 1, 5, 10, 15, 20, 25, 30, etc.).

[0011] As a preferred embodiment of this application, the temperature of the high-temperature field carbonization treatment in the plasma reactor in the preparation step is 3000-5000 K (specifically, it can be 3000 K, 3500 K, 4000 K, 4500 K, 5000 K, etc.).

[0012] As a preferred embodiment of this application, the high-temperature carbonization treatment time in the plasma reactor during the preparation step is 1 to 60 s (specifically, it can be 1s, 5s, 10s, 15s, 20s, 25s, 30s, 35s, 40s, 45s, 50s, 55s, 60s, etc.).

[0013] In a preferred embodiment of this application, the temperature of the tubular converter calcination treatment in the preparation step is 600-1100 ℃ (specifically, it can be 600 ℃, 650 ℃, 700 ℃, 750 ℃, 800 ℃, 850 ℃, 900 ℃, 950 ℃, 1000 ℃, 1050 ℃, 1100 ℃, etc.).

[0014] As a preferred embodiment of this application, the calcination time in the tubular converter during the preparation step is 4 to 8 hours (specifically, 4 hours, 5 hours, 6 hours, 7 hours, 8 hours, etc.).

[0015] In a preferred embodiment of this application, the binder in the preparation step is one of tar, resin, or polyethylene glycol.

[0016] In a preferred embodiment of this application, the carrier gas in the preparation step is N2.

[0017] The present invention also protects a (carbon-based) adsorbent prepared by the above method.

[0018] This invention also protects the application of the (carbon-based) adsorbent described above in the low-temperature adsorption and separation of helium and neon.

[0019] In a preferred embodiment of this application, the low temperature is -196 °C.

[0020] This invention discloses a novel, green method for the instantaneous, continuous, energy-efficient, and structurally tunable preparation of carbon-based adsorbents, applicable to the low-temperature adsorption and separation of helium and neon. The carbon-based adsorbent involved in this invention is prepared by ultrasonically atomizing a mixed solution of sucrose and a metal source, followed by a rapid carbonization process in a high-temperature plasma reactor. This invention achieves atomically uniform dispersion of metal co-doping in the high-temperature plasma reactor by adding a metal source to the atomized solution. The carbon-based adsorbent prepared by this method exhibits smaller microstructures and a higher specific surface area compared to carbon materials prepared by traditional hydrothermal methods, overcoming the technical shortcomings of existing hydrothermal methods. It provides a method for the integrated preparation of sucrose through rapid carbonization, graphitization, and functionalization within milliseconds to seconds using a high-temperature plasma field.

[0021] This invention uses a mixed solution of sucrose and a metal source as the main synthetic raw material. The mixed solution is ultrasonically atomized and then carried by a carrier gas into a high-temperature plasma reactor for rapid carbonization. After water-cooling and rapid quenching, heteroatom-co-doped carbon sphere powder is collected and calcined in a tubular furnace to obtain a carbon-based adsorbent for low-temperature helium-neon separation. This method achieves atomic-level uniform dispersion of the metal co-doping, allowing for more precise control of the internal pore structure of the adsorbent material, resulting in smaller microparticle sizes and a richer pore structure. This significantly improves its adsorption capacity for neon, exhibiting stronger adsorption performance. This invention effectively solves the problems of low neon adsorption capacity, poor adsorption rate, low adsorption performance, and poor gas separation effect currently existing in industrial applications of adsorbents for low-temperature helium-neon separation.

[0022] Compared with the prior art, the beneficial effects of the present invention are as follows: (i) Compared with the materials reported in previous studies, the carbon-based adsorbent prepared by this method innovatively adopts a spray method under high temperature plasma heating conditions to rapidly prepare a carbon-based precursor with a multi-level porous structure, forming smaller micro-particle size and richer pore structure. It has the advantages of short preparation cycle, stable material structure and good preparation repeatability.

[0023] (ii) The carbon-based adsorbent prepared according to this method can efficiently separate and purify helium components in a helium / neon system, exhibiting superior low-temperature neon adsorption performance. (III) The carbon-based adsorbent prepared by the above method uses simple, inexpensive and readily available raw materials. At the same time, the preparation cycle is short, the microstructure is easy to control and the adsorption performance is stable. It is a process technology that can be quickly transformed into engineering and has a very broad application prospect in industrial production. Attached Figure Description

[0024] Figure 1The graph shows the isothermal adsorption curve test results of the adsorbents prepared in Examples 1-7 with respect to the adsorption amount. Figure 2 The graph shows the isothermal adsorption curve test results of the adsorbents prepared in Examples 8-15 with respect to the adsorption amount. Figure 3 The graph shows the isothermal adsorption curve test results of the adsorbents prepared in the blank example and comparative examples 1-4 with respect to the adsorption amount. Figure 4 Infrared spectral curves of the blank comparative sample and sample No. 1 in Example 1; Wherein, a is the blank comparative sample; b is the sample from Example 1; Figure 5 This is a scanning electron microscope image of sample No. 1 in Example 1. Where a: 100 μm SEM image; b: 10 μm SEM image; c: 50 nm TEM image; d: 10 nm TEM image. Detailed Implementation

[0025] A carbon-based adsorbent for low-temperature helium-neon separation and its preparation method are disclosed. The adsorbent uses a mixed solution of sucrose and a metal source as the main raw material. The mixed solution is ultrasonically atomized and then carried into the high-temperature field of a plasma reactor by a carrier gas for rapid carbonization. After water cooling, the carbon sphere powder co-doped with heteroatoms is collected. The carbon sphere powder is then uniformly mixed with an appropriate amount of binder, extruded into strips, and calcined in a tubular converter at a certain temperature for a certain time to finally obtain the carbon-based adsorbent for low-temperature helium-neon separation.

[0026] The specific preparation process is as follows: (1) Sucrose and a metal source are dissolved together in deionized water. The above mixed solution is ultrasonically atomized and then carried by N2 into a high-temperature field of a plasma reactor at a temperature of 3000-5000 K for rapid carbonization. After 1-60 s, the mixture is collected by water cooling to obtain heteroatom co-doped carbon sphere powder. The metal source is one of magnesium nitrate, magnesium sulfate, ferric nitrate, ferric sulfate, copper nitrate, copper sulfate, zinc nitrate, zinc sulfate, chromium nitrate, chromium sulfate, cobalt nitrate, cobalt sulfate, nickel nitrate, nickel sulfate, manganese nitrate, manganese sulfate, lanthanum nitrate, lanthanum sulfate, cerium nitrate, and cerium sulfate. The mass ratio of the metal source to sucrose is 1-30. (2) Take the above carbon ball powder and mix it evenly with an appropriate amount of binder, then extrude it into strips, and then transfer all the formed carbon ball particles to a tube converter and calcine them at a temperature of 600-1100 °C for 2-10 h to finally obtain a carbon-based adsorbent for low-temperature helium-neon separation; wherein, the binder is one of tar, resin, and polyethylene glycol.

[0027] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of this application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0029] It should be noted that the terminology used herein is for the purpose of describing particular implementations only and is not intended to limit the exemplary implementations according to this application. As used herein, the singular form includes the plural form unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this description, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0030] In this invention, some conventional operating equipment, devices and components have been omitted or only briefly described.

[0031] Unless otherwise specified in the examples, the conditions shall be performed in accordance with the standard conditions or the conditions recommended by the manufacturer.

[0032] Example 1 A carbon-based adsorbent for low-temperature helium-neon separation and its preparation method, comprising the following steps: (1) Take 300 g of sucrose and 30 g of magnesium nitrate and dissolve them together in 1000 mL of deionized water. After ultrasonic atomization, the solution is carried by N2 into the high temperature field of a plasma reactor at 3750 K for rapid carbonization. After 30 s, the solution is collected by water cooling to obtain heteroatom co-doped carbon sphere powder. (2) Take 50 g of the above carbon ball powder and mix it evenly with 5 g of tar, then extrude it into strips. Then transfer all the formed carbon ball particles to a tube converter and calcine them at 850 °C for 6 h to finally obtain a carbon-based adsorbent for low-temperature helium-neon separation, which is recorded as Sample No. 1 of Example.

[0033] The equilibrium adsorption capacity of the sample for Ne was determined using an isothermal adsorption-desorption apparatus at -196 ℃ and 100 Pa. The results are shown in Table 2 (adsorption curves are attached). Figure 1 ).

[0034] Example 2 A carbon-based adsorbent for low-temperature helium-neon separation and its preparation method, comprising the following steps: (1) Take 300 g of sucrose and 30 g of ferric nitrate and dissolve them together in 1000 mL of deionized water. After ultrasonic atomization, the solution is carried by N2 into the high temperature field of a plasma reactor at 3750 K for rapid carbonization. After 30 s, the solution is collected by water cooling to obtain heteroatom co-doped carbon sphere powder. (2) Take 50 g of the above carbon ball powder and 5 g of tar, mix them evenly, and then extrude them into strips. Then transfer all the formed carbon ball particles to a tube converter and calcine them at 850 °C for 6 h to finally obtain a carbon-based adsorbent for low-temperature helium-neon separation, which is recorded as Sample No. 2 of Example.

[0035] The equilibrium adsorption capacity of the sample for Ne was determined using an isothermal adsorption-desorption apparatus at -196 ℃ and 100 Pa. The results are shown in Table 2 (adsorption curves are attached). Figure 1 ).

[0036] Example 3 A carbon-based adsorbent for low-temperature helium-neon separation and its preparation method, comprising the following steps: (1) Take 300 g of sucrose and 60 g of magnesium nitrate and dissolve them together in 1000 mL of deionized water. After ultrasonic atomization, the solution is carried by N2 into the high temperature field of a plasma reactor at 3750 K for rapid carbonization. After 30 s, the solution is collected by water cooling to obtain heteroatom co-doped carbon sphere powder. (2) Take 50 g of the above carbon ball powder and mix it evenly with 5 g of tar, then extrude it into strips. Then transfer all the formed carbon ball particles to a tube converter and calcine them at 850 °C for 6 h to finally obtain a carbon-based adsorbent for low-temperature helium-neon separation, which is recorded as Sample No. 3 of Example.

[0037] The equilibrium adsorption capacity of the sample for Ne was determined using an isothermal adsorption-desorption apparatus at -196 ℃ and 100 Pa. The results are shown in Table 2 (adsorption curves are attached). Figure 1 ).

[0038] Example 4 A carbon-based adsorbent for low-temperature helium-neon separation and its preparation method, comprising the following steps: (1) Take 300 g of sucrose and 30 g of magnesium nitrate and dissolve them together in 1000 mL of deionized water. After ultrasonic atomization, the solution is carried by N2 into the high temperature field of a plasma reactor at 3250 K for rapid carbonization. After 30 s, the solution is collected by water cooling to obtain heteroatom co-doped carbon sphere powder. (2) Take 50 g of the above carbon ball powder and mix it evenly with 5 g of tar, then extrude it into strips. Then transfer all the formed carbon ball particles to a tube converter and calcine them at 850 °C for 6 h to finally obtain a carbon-based adsorbent for low-temperature helium-neon separation, which is recorded as Sample No. 4 of Example.

[0039] The equilibrium adsorption capacity of the sample for Ne was determined using an isothermal adsorption-desorption apparatus at -196 ℃ and 100 Pa. The results are shown in Table 2 (adsorption curves are attached). Figure 1 ).

[0040] Example 5 A carbon-based adsorbent for low-temperature helium-neon separation and its preparation method, comprising the following steps: (1) Take 300 g of sucrose and 30 g of magnesium nitrate and dissolve them together in 1000 mL of deionized water. After ultrasonic atomization, the solution is carried by N2 into the high temperature field of a plasma reactor at 4750 K for rapid carbonization. After 30 s, the solution is collected by water cooling to obtain heteroatom co-doped carbon sphere powder. (2) Take 50 g of the above carbon ball powder and mix it evenly with 5 g of tar, then extrude it into strips. Then transfer all the formed carbon ball particles to a tube converter and calcine them at 850 °C for 6 h to finally obtain a carbon-based adsorbent for low-temperature helium-neon separation, which is recorded as Sample No. 5 of Example.

[0041] The equilibrium adsorption capacity of the sample for Ne was determined using an isothermal adsorption-desorption apparatus at -196 ℃ and 100 Pa. The results are shown in Table 2 (adsorption curves are attached). Figure 1 ).

[0042] Example 6 A carbon-based adsorbent for low-temperature helium-neon separation and its preparation method, comprising the following steps: (1) Take 300 g of sucrose and 30 g of magnesium nitrate and dissolve them together in 1000 mL of deionized water. After ultrasonic atomization, the solution is carried by N2 into the high temperature field of a plasma reactor at 3750 K for rapid carbonization. After 15 s, the solution is collected by water cooling to obtain heteroatom co-doped carbon sphere powder. (2) Take 50 g of the above carbon ball powder and mix it evenly with 5 g of tar, then extrude it into strips. Then transfer all the formed carbon ball particles to a tube converter and calcine them at 850 °C for 6 h to finally obtain a carbon-based adsorbent for low-temperature helium-neon separation, which is recorded as Sample No. 6 of Example.

[0043] The equilibrium adsorption capacity of the sample for Ne was determined using an isothermal adsorption-desorption apparatus at -196 ℃ and 100 Pa. The results are shown in Table 2 (adsorption curves are attached). Figure 1 ).

[0044] Example 7 A carbon-based adsorbent for low-temperature helium-neon separation and its preparation method, comprising the following steps: (1) Take 300 g of sucrose and 30 g of magnesium nitrate and dissolve them together in 1000 mL of deionized water. After ultrasonic atomization, the solution is carried by N2 into the high temperature field of a plasma reactor at 3750 K for rapid carbonization. After 45 s, the solution is collected by water cooling to obtain heteroatom co-doped carbon sphere powder. (2) Take 50 g of the above carbon ball powder and 5 g of tar, mix them evenly, and then extrude them into strips. Then transfer all the formed carbon ball particles to a tube converter and calcine them at 850 °C for 6 h to finally obtain a carbon-based adsorbent for low-temperature helium-neon separation, which is recorded as Sample No. 7 of Example.

[0045] The equilibrium adsorption capacity of the sample for Ne was determined using an isothermal adsorption-desorption apparatus at -196 ℃ and 100 Pa. The results are shown in Table 2 (adsorption curves are attached). Figure 1 ).

[0046] Example 8 A carbon-based adsorbent for low-temperature helium-neon separation and its preparation method, comprising the following steps: (1) Take 300 g of sucrose and 30 g of magnesium nitrate and dissolve them together in 1000 mL of deionized water. After ultrasonic atomization, the solution is carried by N2 into the high temperature field of a plasma reactor at 3750 K for rapid carbonization. After 30 s, the solution is collected by water cooling to obtain heteroatom co-doped carbon sphere powder. (2) Take 50 g of the above carbon ball powder and 5 g of tar, mix them evenly, and then extrude them into strips. Then transfer all the formed carbon ball particles to a tube converter and calcine them at 700 °C for 6 h to finally obtain a carbon-based adsorbent for low-temperature helium-neon separation, which is recorded as Sample No. 8 of Example.

[0047] The equilibrium adsorption capacity of the sample for Ne was determined using an isothermal adsorption-desorption apparatus at -196 ℃ and 100 Pa. The results are shown in Table 2 (adsorption curves are attached). Figure 2 ).

[0048] Example 9 A carbon-based adsorbent for low-temperature helium-neon separation and its preparation method, comprising the following steps: (1) Take 300 g of sucrose and 30 g of magnesium nitrate and dissolve them together in 1000 mL of deionized water. After ultrasonic atomization, the solution is carried by N2 into the high temperature field of a plasma reactor at 3750 K for rapid carbonization. After 30 s, the solution is collected by water cooling to obtain heteroatom co-doped carbon sphere powder. (2) Take 50 g of the above carbon ball powder and mix it evenly with 5 g of tar, then extrude it into strips. Then transfer all the formed carbon ball particles to a tube converter and calcine them at 950 °C for 6 h to finally obtain a carbon-based adsorbent for low-temperature helium-neon separation, which is recorded as Sample No. 9 of Example.

[0049] The equilibrium adsorption capacity of the sample for Ne was determined using an isothermal adsorption-desorption apparatus at -196 ℃ and 100 Pa. The results are shown in Table 2 (adsorption curves are attached). Figure 2 ).

[0050] Example 10 A carbon-based adsorbent for low-temperature helium-neon separation and its preparation method, comprising the following steps: (1) Take 300 g of sucrose and 30 g of magnesium nitrate and dissolve them together in 1000 mL of deionized water. After ultrasonic atomization, the solution is carried by N2 into the high temperature field of a plasma reactor at 3750 K for rapid carbonization. After 30 s, the solution is collected by water cooling to obtain heteroatom co-doped carbon sphere powder. (2) Take 50 g of the above carbon ball powder and mix it evenly with 5 g of tar, then extrude it into strips. Then transfer all the formed carbon ball particles to a tube converter and calcine them at 850 °C for 3 h to finally obtain a carbon-based adsorbent for low-temperature helium-neon separation, which is recorded as Sample No. 10 of Example.

[0051] The equilibrium adsorption capacity of the sample for Ne was determined using an isothermal adsorption-desorption apparatus at -196 ℃ and 100 Pa. The results are shown in Table 2 (adsorption curves are attached). Figure 2 ).

[0052] Example 11 A carbon-based adsorbent for low-temperature helium-neon separation and its preparation method, comprising the following steps: (1) Take 300 g of sucrose and 30 g of magnesium nitrate and dissolve them together in 1000 mL of deionized water. After ultrasonic atomization, the solution is carried by N2 into the high temperature field of a plasma reactor at 3750 K for rapid carbonization. After 30 s, the solution is collected by water cooling to obtain heteroatom co-doped carbon sphere powder. (2) Take 50 g of the above carbon ball powder and mix it evenly with 5 g of tar, then extrude it into strips. Then transfer all the formed carbon ball particles to a tube converter and calcine them at 850 °C for 9 h to finally obtain a carbon-based adsorbent for low-temperature helium-neon separation, which is recorded as Sample No. 11 of Example.

[0053] The equilibrium adsorption capacity of the sample for Ne was determined using an isothermal adsorption-desorption apparatus at -196 ℃ and 100 Pa. The results are shown in Table 2 (adsorption curves are attached). Figure 2 ).

[0054] Example 12 A carbon-based adsorbent for low-temperature helium-neon separation and its preparation method, comprising the following steps: (1) Take 300 g of sucrose and 30 g of magnesium nitrate and dissolve them together in 1000 mL of deionized water. After ultrasonic atomization, the solution is carried by N2 into the high temperature field of a plasma reactor at 3750 K for rapid carbonization. After 30 s, the solution is collected by water cooling to obtain heteroatom co-doped carbon sphere powder. (2) Take 50 g of the above carbon ball powder and 5 g of resin, mix them evenly, and then extrude them into strips. Then transfer all the formed carbon ball particles to a tube converter and calcine them at 850 °C for 6 h to finally obtain a carbon-based adsorbent for low-temperature helium-neon separation, which is recorded as Sample No. 12 of Example.

[0055] The equilibrium adsorption capacity of the sample for Ne was determined using an isothermal adsorption-desorption apparatus at -196 ℃ and 100 Pa. The results are shown in Table 2 (adsorption curves are attached). Figure 2 ).

[0056] Example 13 A carbon-based adsorbent for low-temperature helium-neon separation and its preparation method, comprising the following steps: (1) Take 300 g of sucrose and 30 g of magnesium nitrate and dissolve them together in 1000 mL of deionized water. After ultrasonic atomization, the solution is carried by N2 into the high temperature field of a plasma reactor at 3750 K for rapid carbonization. After 30 s, the solution is collected by water cooling to obtain heteroatom co-doped carbon sphere powder. (2) Take 50 g of the above carbon ball powder and mix it evenly with 5 g of polyethylene glycol, then extrude it into strips. Then transfer all the formed carbon ball particles to a tube converter and calcine them at 850 °C for 6 h to finally obtain a carbon-based adsorbent for low-temperature helium-neon separation, which is recorded as Sample No. 1 of Example.

[0057] The equilibrium adsorption capacity of the sample for Ne was determined using an isothermal adsorption-desorption apparatus at -196 ℃ and 100 Pa. The results are shown in Table 2 (adsorption curves are attached). Figure 2 ).

[0058] Example 14 A carbon-based adsorbent for low-temperature helium-neon separation and its preparation method, comprising the following steps: (1) Take 300 g of sucrose and 30 g of copper sulfate and dissolve them together in 1000 mL of deionized water. After ultrasonic atomization, the solution is carried by N2 into the high temperature field of a plasma reactor at 3750 K for rapid carbonization. After 30 s, the solution is collected by water cooling to obtain heteroatom co-doped carbon sphere powder. (2) Take 50 g of the above carbon ball powder and mix it evenly with 5 g of tar, then extrude it into strips. Then transfer all the formed carbon ball particles to a tube converter and calcine them at 850 °C for 6 h to finally obtain a carbon-based adsorbent for low-temperature helium-neon separation, which is recorded as Sample No. 14 of Example.

[0059] The equilibrium adsorption capacity of the sample for Ne was determined using an isothermal adsorption-desorption apparatus at -196 ℃ and 100 Pa. The results are shown in Table 2 (adsorption curves are attached). Figure 2 ).

[0060] Example 15 A carbon-based adsorbent for low-temperature helium-neon separation and its preparation method, comprising the following steps: (1) Take 300 g of sucrose and 30 g of nickel sulfate and dissolve them together in 1000 mL of deionized water. After ultrasonic atomization, the solution is carried by N2 into the high temperature field of a plasma reactor at 3750 K for rapid carbonization. After 30 s, the solution is collected by water cooling to obtain heteroatom co-doped carbon sphere powder. (2) Take 50 g of the above carbon ball powder and mix it evenly with 5 g of tar, then extrude it into strips. Then transfer all the formed carbon ball particles to a tube converter and calcine them at 850 °C for 6 h to finally obtain a carbon-based adsorbent for low-temperature helium-neon separation, which is recorded as Sample No. 15 of Example.

[0061] The equilibrium adsorption capacity of the sample for Ne was determined using an isothermal adsorption-desorption apparatus at -196 ℃ and 100 Pa. The results are shown in Table 2 (adsorption curves are attached). Figure 2 ).

[0062] The key parameters for Examples 1 to 15 are listed below: Table 1:

[0063] Blank comparison A carbon-based adsorbent for low-temperature helium-neon separation and its preparation method, comprising the following steps: (1) Dissolve 300 g of sucrose in 1000 mL of deionized water. After ultrasonic atomization, the solution is carried by N2 into the high-temperature field of a plasma reactor at 3750 K for rapid carbonization. After 30 s, the solution is collected by water cooling to obtain heteroatom co-doped carbon sphere powder. (2) Take 50 g of the above carbon ball powder and 5 g of tar, mix them evenly, and then extrude them into strips. Then transfer all the formed carbon ball particles to a tube converter and calcine them at 850 °C for 6 h to finally obtain a carbon-based adsorbent for low-temperature helium-neon separation, which is recorded as a blank comparative sample.

[0064] The equilibrium adsorption capacity of the sample for Ne was determined using an isothermal adsorption-desorption apparatus at -196 ℃ and 100 Pa. The results are shown in Table 2 (adsorption curves are attached). Figure 3 ).

[0065] Comparative Example 1 A carbon-based adsorbent for low-temperature helium-neon separation and its preparation method, comprising the following steps: (1) Take 300 g of sucrose and 150 g of magnesium nitrate and dissolve them together in 1000 mL of deionized water. After ultrasonic atomization, the solution is carried by N2 into the high temperature field of a plasma reactor at 3750 K for rapid carbonization. After 30 s, the solution is collected by water cooling to obtain heteroatom co-doped carbon sphere powder. (2) Take 50 g of the above carbon ball powder and 5 g of tar, mix them evenly, and then extrude them into strips. Then transfer all the formed carbon ball particles to a tube converter and calcine them at 850 °C for 6 h to finally obtain a carbon-based adsorbent for low-temperature helium-neon separation, which is recorded as Comparative Example 1.

[0066] The equilibrium adsorption capacity of the sample for Ne was determined using an isothermal adsorption-desorption apparatus at -196 ℃ and 100 Pa. The results are shown in Table 2 (adsorption curves are attached). Figure 3 ).

[0067] Comparative Example 2 A carbon-based adsorbent for low-temperature helium-neon separation and its preparation method, comprising the following steps: (1) Take 300 g of sucrose and 150 g of ferric nitrate and dissolve them together in 1000 mL of deionized water. After ultrasonic atomization, the solution is carried by N2 into the high temperature field of a plasma reactor at 3750 K for rapid carbonization. After 30 s, the solution is collected by water cooling to obtain heteroatom co-doped carbon sphere powder. (2) Take 50 g of the above carbon ball powder and 5 g of tar, mix them evenly, and then extrude them into strips. Then transfer all the formed carbon ball particles to a tube converter and calcine them at 850 °C for 6 h to finally obtain a carbon-based adsorbent for low-temperature helium-neon separation, which is recorded as Comparative Example 2.

[0068] The equilibrium adsorption capacity of the sample for Ne was determined using an isothermal adsorption-desorption apparatus at -196 ℃ and 100 Pa. The results are shown in Table 2 (adsorption curves are attached). Figure 3 ).

[0069] Comparative Example 3 A carbon-based adsorbent for low-temperature helium-neon separation and its preparation method, comprising the following steps: (1) Take 300 g of sucrose and 30 g of magnesium nitrate and dissolve them together in 1000 mL of deionized water. After ultrasonic atomization, the solution is carried by N2 into the high temperature field of a plasma reactor at 1750 K for rapid carbonization. After 30 s, the solution is collected by water cooling to obtain heteroatom co-doped carbon sphere powder. (2) Take 50 g of the above carbon ball powder and mix it evenly with 5 g of tar, then extrude it into strips. Then transfer all the formed carbon ball particles to a tube converter and calcine them at 850 °C for 6 h to finally obtain a carbon-based adsorbent for low-temperature helium-neon separation, which is recorded as Comparative Example 3.

[0070] The equilibrium adsorption capacity of the sample for Ne was determined using an isothermal adsorption-desorption apparatus at -196 ℃ and 100 Pa. The results are shown in Table 2 (adsorption curves are attached). Figure 3 ).

[0071] Comparative Example 4 A carbon-based adsorbent for low-temperature helium-neon separation and its preparation method, comprising the following steps: (1) Take 300 g of sucrose and 30 g of magnesium nitrate and dissolve them together in 1000 mL of deionized water. After ultrasonic atomization, the solution is carried by N2 into the high temperature field of a plasma reactor at 3750 K for rapid carbonization. After 30 s, the solution is collected by water cooling to obtain heteroatom co-doped carbon sphere powder. (2) Take 50 g of the above carbon ball powder and mix it evenly with 5 g of tar, then extrude it into strips. Then transfer all the formed carbon ball particles to a tube converter and calcine them at 450 °C for 6 h to finally obtain a carbon-based adsorbent for low-temperature helium-neon separation, which is recorded as Comparative Example 4.

[0072] The equilibrium adsorption capacity of the sample for Ne was determined using an isothermal adsorption-desorption apparatus at -196 ℃ and 100 Pa. The results are shown in Table 2 (adsorption curves are attached). Figure 3 ).

[0073] Table 2. Results of equilibrium adsorption capacity determination of Ne by carbon-based adsorbents in the examples and comparative examples.

[0074] The test results in Table 2 show that the carbon-based adsorbents (such as the samples in Examples 1 to 5) prepared by ultrasonically atomizing a mixed solution of sucrose and a metal source and then rapidly carbonizing it in a high-temperature field of a plasma reactor exhibit high neon equilibrium adsorption capacity while almost not adsorbing helium. Furthermore, compared to the blank control sample without a metal source, the samples with a metal source have a higher neon equilibrium adsorption capacity, with the sample containing magnesium nitrate showing the most significant increase. The carbonization temperature in the plasma reactor, the calcination temperature in the tubular converter, and the type and mass ratio of the metal source all have varying degrees of influence on the adsorption performance of the samples. Figure 3 As can be seen from the infrared spectrum curves, compared with the blank control sample without a metal source, the sample with a metal source showed stronger functional group signal peaks; from Figure 4 The scanning electron microscope images show that the sample with added metal source has smaller microparticle size and richer pore structure, thus exhibiting stronger adsorption performance.

[0075] The above results indicate that the method of the present invention uses a mixed solution of sucrose and a metal source as the main synthetic raw material. After ultrasonic atomization, the mixed solution is carried into the high-temperature field of a plasma reactor by a carrier gas for rapid carbonization. Then, after water-cooling and rapid quenching, heteroatom co-doped carbon sphere powder is collected. After calcination in a tubular converter, a carbon-based adsorbent for low-temperature helium-neon separation is obtained. This method can achieve atomic-level uniform dispersion of metal co-doping, thereby enabling more precise control of the internal pore structure of the adsorbent material, forming smaller microparticle sizes and richer pore structures, which greatly improves its adsorption capacity for neon and exhibits stronger adsorption performance.

[0076] The embodiments described above merely illustrate specific implementation methods of this application, and while the descriptions are detailed and specific, they should not be construed as limiting the scope of protection of this application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the technical solution of this application, and these modifications and improvements all fall within the scope of protection of this application.

[0077] This background section is provided to generally present the context of the invention. The work of the currently named inventors, the work to the extent described in this background section, and aspects of this section that did not constitute prior art at the time of application are neither expressly nor impliedly acknowledged as prior art to the invention.

Claims

1. A method for preparing an adsorbent for low-temperature helium-neon separation, characterized in that: The adsorbent is synthesized using a mixed solution of sucrose and metal source as the main raw material. The mixed solution is ultrasonically atomized and then carried into the high-temperature field of the plasma reactor by a carrier gas for rapid carbonization. After being rapidly cooled by water, the carbon sphere powder co-doped with heteroatoms is collected. The carbon sphere powder is then uniformly mixed with a binder, extruded into strips, and calcined in a tubular converter at a certain temperature for a certain time to finally obtain a carbon-based adsorbent for low-temperature helium-neon separation.

2. The method for preparing the adsorbent according to claim 1, characterized in that: The metal source is any one of magnesium nitrate, magnesium sulfate, ferric nitrate, ferric sulfate, copper nitrate, copper sulfate, zinc nitrate, zinc sulfate, chromium nitrate, chromium sulfate, cobalt nitrate, cobalt sulfate, nickel nitrate, nickel sulfate, manganese nitrate, manganese sulfate, lanthanum nitrate, lanthanum sulfate, cerium nitrate, and cerium sulfate.

3. The method for preparing the adsorbent according to claim 1, characterized in that: The mass ratio of sucrose to metal source is 1–30.

4. The method for preparing the adsorbent according to claim 1, characterized in that: The rapid carbonization in the high-temperature field of the plasma reactor is carried out at a temperature of 3000–5000 K for a time of 1–60 s.

5. The method for preparing the adsorbent according to claim 1, characterized in that: The adhesive is any one of tar, resin, and polyethylene glycol.

6. The method for preparing the adsorbent according to claim 1, characterized in that: The calcination temperature in the tubular converter is 600–1100 °C, and the time is 4–8 h.

7. The method for preparing the adsorbent according to claim 1, characterized in that: The carrier gas is N2.

8. The adsorbent prepared by the method according to any one of claims 1-7.

9. The application of the adsorbent as described in claim 8 in the low-temperature adsorption separation of helium and neon.

10. The application of the adsorbent as described in claim 9 in the low-temperature adsorption separation of helium and neon, characterized in that: The low temperature in the low-temperature adsorption separation is -196 ℃.

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