A volatile organic compound adsorbent material and its preparation method

Abstract

This invention relates to a volatile organic compound (VOC) adsorbent material and its preparation method. The method involves first modifying a 5A molecular sieve with lithium, followed by vanadium modification to obtain a Li-V-5A adsorbent material. Based on the total mass of the adsorbent material, the Li content is 0.8%–4.5%, and the V content is 0.2%–1%. The adsorbent material obtained by this invention, using a 5A molecular sieve as a matrix and modified to obtain the Li-V-5A adsorbent material, has advantages such as good adsorption effect on low-carbon hydrocarbons and strong resistance to sulfur poisoning, especially high adsorption and removal rate of ethane.

Description

Technical Field

[0001] This invention belongs to the field of air pollution control technology, specifically relating to a volatile organic compound adsorbent material and its preparation method. Background Technology

[0002] Volatile organic compounds (VOCs) are among the major air pollutants and are important reactants involved in the formation of photochemical smog and haze. Excessive VOCs pose serious threats to human health and the ecological environment. Among the VOCs emitted by the chemical industry, ethane and propane are relatively small molecules with weak polarity, making them often difficult to remove.

[0003] VOCs adsorption and separation technology is suitable for treating low-concentration VOCs waste gas. The key to adsorption purification efficiency lies in the adsorption material. The high specific surface area and suitable pore structure of the adsorption material trap VOCs pollutants through chemical or physical adsorption, achieving waste gas purification. VOCs are complex in type; the larger the molecular weight and the stronger the polarity, the easier they are to adsorb. However, low-carbon hydrocarbons, especially ethane and propane, are smaller VOC molecules with weaker polarity, making it difficult for conventional adsorption materials to achieve efficient adsorption. Furthermore, VOCs waste gas often contains sulfur-containing substances such as hydrogen sulfide, which can lead to adsorbent poisoning and inactivation during adsorption. Therefore, improving the sulfur poisoning resistance of molecular sieves is essential.

[0004] CN201710620400.6 discloses a polydopamine-asphalt-based composite porous carbon adsorbent material that preferentially adsorbs ethane, its preparation method, and its application. The method includes the following steps: carbonizing asphalt at high temperature in a nitrogen atmosphere to obtain an asphalt-based non-porous carbon material; acidifying the asphalt-based non-porous carbon material to obtain an acid-treated asphalt-based non-porous carbon material; adding a dopamine hydrochloride aqueous solution (solution B) to a mixture A of the acid-treated asphalt-based non-porous carbon material, ethanol, water, and ammonia to react and obtain a polydopamine-asphalt-based composite carbon material; mixing the polydopamine-asphalt-based composite carbon material with KOH and then activating it in a nitrogen atmosphere to obtain the polydopamine-asphalt-based composite porous carbon adsorbent material. This porous carbon adsorbent material exhibits preferential adsorption of ethane and has a specific surface area of ​​up to 1500 m². 2The adsorption capacity of ethane at 0.3 bar and 298 K is between 4.3 and 4.52 mmol / g. CN202110917888.5 discloses an oxygen-containing microporous activated carbon material, its preparation method, and its application in the selective adsorption of ethane. In the oxygen-containing microporous activated carbon, the sum of the volumes of pores with a pore size distribution between 5 and 15 Å is 40% to 80% of the total pore volume, and the adsorption capacity for ethane at 1 bar and 25 °C can reach more than 6 mmol / g. The preparation method includes: grinding and mixing biomass char with KOH at a mass ratio of 1:1 to 10, vacuum drying, and activation in an inert atmosphere at 300 to 1000 °C. The activation product is then washed and dried to obtain the oxygen-containing microporous activated carbon. However, both patents have poor adsorption capacity under normal pressure conditions, so they are adsorption effects under pressure. Furthermore, the adsorption material is a carbon-based material, which poses a safety risk due to the exothermic process during VOCs adsorption, and deep thermal regeneration is difficult.

[0005] CN202111346199.X discloses a method for preparing ethane-adsorbing silica gel. This method involves modifying the surface of silica gel with alkali metal ions to prepare a silica-based adsorbent, thereby altering the adsorption capacity of the silica gel for ethane. Specific steps include: intensifying the mixing of sodium silicate solution and dilute sulfuric acid solution to form a hydrogel through neutralization; then, soaking the hydrogel in HCl to fix the framework and prevent further neutralization reactions within the silica gel; washing the acid-soaked hydrogel with deionized water; subsequently, using an equal-volume impregnation method, modifying the surface of the washed silica gel with alkali metal ions using BaCl2 solution; and finally, drying to obtain the ethane-adsorbing silica gel. This ethane-adsorbing silica gel exhibits increased micropore count and a micropore specific surface area reaching 480 m². 2 The adsorption capacity for ethane can reach 20-22.0 ml / g, which is less than 1 mmol / g after conversion, indicating a relatively low adsorption capacity. Summary of the Invention

[0006] To address the shortcomings of existing adsorption materials, this invention provides a volatile organic compound adsorption material and its preparation method. The adsorption material obtained by the method of this invention is a Li-V-5A adsorption material obtained by modification of 5A molecular sieve as the matrix. It has advantages such as good adsorption effect on low-carbon hydrocarbons and strong resistance to sulfur poisoning, especially high adsorption and removal rate of ethane.

[0007] The volatile organic compound adsorbent provided by this invention is a Li-V-5A adsorbent obtained by first modifying 5A molecular sieve with lithium and then modifying it with vanadium. The content of Li is 0.8% to 4.5% and the content of V is 0.2% to 1% based on the total mass of the adsorbent.

[0008] In the adsorption material of this invention, micropores account for more than 85%, and the sum of the volumes of pores with a pore size between 4 and 6 Å is 60% to 80% of the total pore volume.

[0009] In the adsorbent material of this invention, the specific surface area of ​​the Li-V-5A adsorbent material is 450–520 m². 2 / g, pore volume 0.24~0.28 cm³ 3 / g.

[0010] The present invention also provides a method for preparing a volatile organic compound adsorbent material, comprising the following steps: (1) immersing a 5A molecular sieve in a lithium salt solution, and then filtering, washing, drying and calcining to obtain a Li-5A molecular sieve; (2) immersing the Li-5A molecular sieve in a vanadium salt solution, and then filtering, washing, drying and calcining to obtain a Li-V-5A adsorbent material.

[0011] In the method of this invention, the 5A molecular sieve in step (1) has the following properties: a specific surface area of ​​400-550 m². 2 / g, preferably 500-550m 2 / g, pore volume 0.2~0.5cm 3 / g, preferably 0.28~0.35cm 3 / g, with an average pore size of 1-3nm and an average particle diameter of 1-3mm. It can be prepared in-house or purchased commercially; in-house preparation is achieved through a hydrothermal method.

[0012] In the method of the present invention, the lithium salt solution in step (1) is at least one of LiCl solution, lithium nitrate solution, lithium sulfate solution, etc., preferably LiCl solution. The concentration of the lithium salt solution is generally 0.3 to 2.0 mol / L, preferably 0.5 to 1.5 mol / L.

[0013] In the method of the present invention, the mass-to-volume ratio of the 5A molecular sieve to the lithium salt solution in step (1) is 1g:5-13mL.

[0014] In the method of the present invention, in step (1), the 5A molecular sieve is immersed in a lithium salt solution at a temperature of 60-90°C, preferably 70-80°C, for a time of 1-5 hours, preferably 1-2 hours.

[0015] In the method of this invention, the filtration and washing in step (1) can be carried out using conventional methods in the art. Washing can be performed using deionized water until no lithium ions are detected. The drying conditions are: drying temperature 70-120℃, preferably 80-100℃, drying time 2-10h, preferably 2-5h. The calcination conditions are: calcination temperature 450-600℃, preferably 500-550℃, calcination time 1-10h, preferably 2-6h.

[0016] In the method of this invention, the vanadium salt in step (2) is a soluble vanadium salt, specifically at least one of ammonium metavanadate, sodium vanadate, vanadium oxalate, and vanadium oxalate, with ammonium metavanadate being preferred. The vanadium content in the vanadium salt solution is generally 0.05–0.5 mol / L, preferably 0.1–0.3 mol / L.

[0017] In the method of the present invention, the mass-to-volume ratio of Li-5A molecular sieve to vanadium salt solution in step (2) is 1g:20-50mL.

[0018] In the method of the present invention, in step (2), Li-5A molecular sieve is immersed in vanadium salt solution for treatment at room temperature, preferably 15-30°C, for 1-5 hours, preferably 1-2 hours.

[0019] In the method of this invention, the filtration and washing in step (2) are carried out using conventional methods in the art, and deionized water is used for washing until no vanadium ions are detected. The drying conditions are: drying temperature 70-120℃, preferably 80-100℃, drying time 2-10h, preferably 2-5h. The calcination conditions are: calcination temperature 450-600℃, preferably 500-550℃, calcination time 1-10h, preferably 2-6h.

[0020] The Li-V-5A molecular sieve adsorption material described in this invention is used for the adsorption and separation of low-carbon hydrocarbons in VOCs.

[0021] In this invention, the low-carbon hydrocarbons in VOCs are mainly C2-C4 low-carbon hydrocarbons, specifically ethane, propane, etc., preferably ethane. The concentration of low-carbon hydrocarbons in VOCs is 100-1000 mg / m³. 3 .

[0022] In this invention, the adsorption conditions are as follows: the adsorption bed temperature is room temperature, preferably 15–32°C; the bed pressure is atmospheric pressure; and the volume hourly space velocity is 100–500 h⁻¹. -1 .

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] (1) First, 5A molecular sieve is modified with lithium salt solution, and then Li-V-5A adsorbent material is obtained by vanadium salt modification. Through the cooperation between the substances and the two-step modification, most of the pore sizes in the adsorbent material are between 0.4 and 0.6 nm, which is conducive to the selective adsorption of low carbon hydrocarbons. In particular, most of the molecular dynamics of ethane are about 0.4 nm, which effectively enhances the adsorption capacity of 5A molecular sieve for ethane.

[0025] (2) By using metal Li ions to regulate the pore structure of molecular sieves, not only can the pore size be close to the molecular dynamics size of small molecule VOCs, but the surface charge is also changed, the electronegativity is weakened, and the adsorption capacity of small molecule VOCs is enhanced.

[0026] (3) Replacing Ca in the 5A molecular sieve framework with V, which has a similar atomic size, increases the surface acidity and the adsorption capacity of low-carbon hydrocarbons without affecting the pore structure. At the same time, it increases the surface polarity of the material and enhances the Coulomb field adsorption effect in the pore structure of the molecular sieve, which helps to improve the adsorption performance of low-carbon hydrocarbons. In addition, V modification also improves the adsorbent's resistance to sulfur poisoning, enabling the adsorbent material to have better adsorption performance and regeneration efficiency under sulfur-containing conditions. Detailed Implementation

[0027] The following embodiments further illustrate the technical solution and effects of the present invention. These embodiments are implemented based on the technical solution of the present invention, providing detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.

[0028] Unless otherwise specified, the experimental methods used in the following examples are conventional methods in the art. Unless otherwise specified, the experimental materials used in the following examples were purchased from conventional biochemical reagent stores.

[0029] The specific surface area and pore volume involved in the embodiments of this invention were obtained by analyzing the adsorption-desorption curves using an N2 adsorption analyzer. The Li and V contents in the material were obtained by ICP-OES analysis. The adsorption capacity of the material for ethane was obtained by testing with a gas dynamic adsorption analyzer.

[0030] Example 1

[0031] Commercially purchased 5A molecular sieve has the following properties: specific surface area: 545 m² 2 / g, pore volume: 0.34cm 3 / g, average pore size: 2.1nm, average particle diameter: 2.5mm. The modification process is as follows:

[0032] (1) The 5A molecular sieve was immersed in a LiCl solution with a concentration of 1.2 mol / L. The mass-volume ratio of 5A molecular sieve to lithium salt solution was 1 g: 10 mL. The solution was treated at 75 °C for 1 hour. After treatment, the solution was filtered, washed with deionized water, dried at 100 °C for 4 hours, and calcined at 500 °C for 6 hours to obtain Li-5A molecular sieve.

[0033] (2) The Li-5A molecular sieve was immersed in an ammonium metavanadate solution with a vanadium content of 0.25 mol / L. The mass-volume ratio of Li-5A molecular sieve to vanadium salt solution was 1 g: 35 mL. The solution was treated at room temperature for 2 h, filtered, washed with deionized water, dried at 100 °C for 4 h, and calcined at 500 °C for 5 h to obtain Li-V-5A adsorbent material.

[0034] The prepared Li-V-5A adsorbent material, by total mass, contains 2.72% Li, 0.64% V, and has a specific surface area of ​​480 m². 2 / g, pore volume is 0.26cm 3 / g, of which micropores account for 87.5%, and the sum of the volumes of pores with a pore size between 4 and 6 Å accounts for 72.5% of the total pore volume.

[0035] Example 2

[0036] Commercially purchased 5A molecular sieve has the following properties: specific surface area: 510 m² 2 / g, pore volume: 0.3cm 3 / g, average pore size: 2.0nm, average particle diameter: 2.3mm. The modification process is as follows:

[0037] (1) The 5A molecular sieve was immersed in a 0.3 mol / L LiCl solution with a mass-volume ratio of 1 g to 13 mL of 5A molecular sieve and lithium salt solution. The solution was treated at 60 °C for 2 hours, filtered after treatment, washed with deionized water, dried at 80 °C for 6 hours, and calcined at 600 °C for 3 hours to obtain Li-5A molecular sieve.

[0038] (2) The Li-5A molecular sieve was immersed in an ammonium metavanadate solution with a vanadium content of 0.5 mol / L. The mass-volume ratio of Li-5A molecular sieve to vanadium salt precursor solution was 1 g: 20 mL. The solution was treated at room temperature for 3 h, filtered, washed with deionized water, dried at 120 °C for 4 h, and calcined at 450 °C for 6 h to obtain Li-V-5A adsorbent material.

[0039] The prepared Li-V-5A adsorbent material, by total mass, contains 0.82% Li, 0.98% V, and has a specific surface area of ​​452 m². 2 / g, pore volume 0.24cm 3 / g, of which micropores account for 86.1%, and the sum of the volumes of pores with a pore size between 4 and 6 Å accounts for 63.1% of the total pore volume.

[0040] Example 3

[0041] Commercially purchased 5A molecular sieve has the following properties: specific surface area: 520 m² 2 / g, pore volume: 0.32cm3 / g, average pore size: 2.2nm, average particle diameter: 2.9mm. The modification process is as follows:

[0042] (1) The 5A molecular sieve was immersed in a LiCl solution with a concentration of 1.5 mol / L. The mass-volume ratio of 5A molecular sieve to lithium salt solution was 1 g: 5 mL. The solution was treated at 80 °C for 1 hour. After treatment, the solution was filtered, washed with deionized water, dried at 100 °C for 4 hours, and calcined at 450 °C for 4 hours to obtain Li-5A molecular sieve.

[0043] (2) The Li-5A molecular sieve was immersed in an ammonium metavanadate solution with a vanadium content of 0.1 mol / L. The mass-volume ratio of Li-5A molecular sieve to vanadium salt precursor solution was 1 g: 20 mL. The solution was treated at room temperature for 2 h, filtered, washed with deionized water, dried at 80 °C for 6 h, and calcined at 550 °C for 6 h to obtain Li-V-5A adsorbent material.

[0044] The prepared Li-V-5A adsorbent material, by total mass, contains 4.27% Li, 0.36% V, and has a specific surface area of ​​495 m². 2 / g, pore volume 0.27cm 3 / g, of which micropores account for 88.7%, and the sum of the volumes of pores with a pore size between 4 and 6 Å accounts for 70.2% of the total pore volume.

[0045] Example 4

[0046] Similar to Example 1, except that lithium nitrate was used as the lithium salt. The prepared Li-V-5A adsorbent material, by total mass, contained 2.84% Li, 0.71% V, and had a specific surface area of ​​468 m². 2 / g, pore volume 0.25cm 3 / g, of which micropores account for 86.8%, and the sum of the volumes of pores with a pore size between 4 and 6 Å accounts for 71.8% of the total pore volume.

[0047] Example 5

[0048] Similar to Example 1, except that lithium sulfate was used as the lithium salt. The prepared Li-V-5A molecular sieve, by total mass, contained 2.61% Li, 0.6% V, and had a specific surface area of ​​492 m². 2 / g, pore volume 0.27cm 3 / g, of which micropores account for 88.4%, and the sum of the volumes of pores with a pore size between 4 and 6 Å accounts for 72.1% of the total pore volume.

[0049] Example 6

[0050] Similar to Example 1, except that sodium vanadate is used instead of vanadium salt. The prepared Li-V-5A molecular sieve, by total mass, contains 2.68% Li, 0.76% V, and has a specific surface area of ​​455 m². 2 / g, pore volume 0.25cm 3 / g, of which micropores account for 85.1%, and the sum of the volumes of pores with a pore size between 4 and 6 Å accounts for 65.7% of the total pore volume.

[0051] Example 7

[0052] Similar to Example 1, except that vanadium oxysulfate was used as the vanadium salt. The prepared Li-V-5A molecular sieve, by total mass, contained 2.81% Li, 0.62% V, and had a specific surface area of ​​475 m². 2 / g, pore volume 0.27cm 3 / g, of which micropores account for 87.9%, and the sum of the volumes of pores with a pore size between 4 and 6 Å accounts for 71.6% of the total pore volume.

[0053] Example 8

[0054] Similar to Example 1, except that vanadium oxalate salt was used instead of vanadium oxalate. The prepared Li-V-5A molecular sieve, by total mass, contained 2.89% Li, 0.74% V, and had a specific surface area of ​​452 m². 2 / g, pore volume 0.25cm 3 / g, of which micropores account for 85.1%, and the sum of the volumes of pores with a pore size between 4 and 6 Å accounts for 67.6% of the total pore volume.

[0055] Comparative Example 1

[0056] Same as Example 1, except that only step (1) is performed to obtain Li-5A molecular sieve material, wherein the Li content is 2.89% and the specific surface area is 474 m². 2 / g, pore volume 0.26 cm³ 3 / g, of which micropores account for 74.6%, and the sum of the volumes of pores with a pore size between 4 and 6 Å accounts for 65.7% of the total pore volume.

[0057] Comparative Example 2

[0058] Same as Example 1, except that only step (2) is performed to obtain V-5A molecular sieve material, wherein the V content is 0.69% and the specific surface area is 466 m². 2 / g, pore volume 0.25 cm³ 3 / g, of which micropores account for 68.5%, and the sum of the volumes of pores with a pore size between 4 and 6 Å accounts for 61.6% of the total pore volume.

[0059] Comparative Example 3

[0060] Similar to Example 1, except that vanadium salt was used for treatment first, followed by lithium salt treatment. The prepared Li-V-5A adsorbent material, by total mass, contained 0.52% Li, 1.35% V, and had a specific surface area of ​​352 m². 2 / g, pore volume 0.22cm 3 / g, of which micropores account for 62.4%, and the sum of the volumes of pores with a pore size between 4 and 6 Å accounts for 51.5% of the total pore volume.

[0061] Comparative Example 4

[0062] Similar to Example 1, except that the lithium salt treatment temperature was room temperature, i.e., 25 degrees Celsius. The prepared Li-V-5A adsorbent material, by total mass, contained 0.23% Li, 1.76% V, and had a specific surface area of ​​316 m². 2 / g, pore volume is 0.21cm 3 / g, of which micropores account for 56.5%, and the sum of the volumes of pores with a pore size between 4 and 6 Å accounts for 48.2% of the total pore volume.

[0063] Comparative Example 5

[0064] Similar to Example 1, except that manganese salt is used instead of vanadium salt. In the prepared adsorbent material, the content of Li is 0.23% and the content of Mn is 1.76% by total mass, with a specific surface area of ​​316 m². 2 / g, pore volume is 0.21cm 3 / g, of which micropores account for 56.5%, and the sum of the volumes of pores with a pore size between 4 and 6 Å accounts for 48.2% of the total pore volume.

[0065] Test Example 1

[0066] The adsorption capacities of the adsorbents prepared in Examples 1-8 and Comparative Examples 1-5 for ethane, propane, and other organic compounds were tested under ambient temperature and pressure conditions with an adsorption volume space velocity of 500 h⁻¹. -1 The concentration of ethane in the gas mixture is 200 mg / m³. 3 The concentration of propane is 100 mg / m³. 3 The concentration of butane is 100 mg / m³. 3 The concentration of n-hexane is 100 mg / m³. 3 The concentration of benzene is 100 mg / m³. 3 The hydrogen sulfide content is 20 mg / m³. 3 After adsorption reached saturation, the detection results are shown in Table 1.

[0067] Table 1. Test results of the adsorbent materials in the examples and comparative examples.

[0068]

[0069] The specific embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combining the various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A volatile organic compound adsorbent material, characterized in that: The Li-V-5A adsorbent material is obtained by first modifying 5A molecular sieve with lithium and then modifying it with vanadium. The content of Li is 0.8% to 4.5% and the content of V is 0.2% to 1% based on the total mass of the adsorbent material. The preparation method of the volatile organic compound adsorbent material includes the following steps: (1) immersing 5A molecular sieve in lithium salt solution at a temperature of 60 to 90°C, and then filtering, washing, drying and calcining to obtain Li-5A molecular sieve; (2) immersing Li-5A molecular sieve in vanadium salt solution, and then filtering, washing, drying and calcining to obtain Li-V-5A adsorbent material.

2. The adsorbent material according to claim 1, characterized in that: Micropores account for more than 85% of the adsorbent material, and the sum of the volumes of pores with a pore size between 4 and 6 Å accounts for 60% to 80% of the total pore volume.

3. The adsorbent material according to claim 1, characterized in that: The specific surface area of ​​the adsorbent material is 450–520 m². 2 / g, pore volume 0.24~0.28cm³ 3 / g.

4. The adsorbent material according to claim 1, characterized in that: The 5A molecular sieve in step (1) has the following properties: specific surface area of ​​400-550 m². 2 / g, pore volume 0.2~0.5cm 3 / g, with an average pore size of 1-3nm and an average particle diameter of 1-3mm.

5. The adsorbent material according to claim 4, characterized in that: The 5A molecular sieve in step (1) has the following properties: specific surface area of ​​500-550 m². 2 / g, pore volume 0.28~0.35cm³ 3 / g.

6. The adsorbent material according to claim 1, characterized in that: In step (1), the lithium salt solution is at least one of LiCl solution, lithium nitrate solution, and lithium sulfate solution.

7. The adsorbent material according to claim 6, characterized in that: In step (1), the lithium salt solution is a LiCl solution.

8. The adsorbent material according to claim 1, 6, or 7, characterized in that: The concentration of the lithium salt solution in step (1) is 0.3 to 2.0 mol / L.

9. The adsorbent material according to claim 8, characterized in that: The concentration of the lithium salt solution in step (1) is 0.5 to 1.5 mol / L.

10. The adsorbent material according to claim 1, 6, or 7, characterized in that: The mass-to-volume ratio of the 5A molecular sieve to the lithium salt solution in step (1) is 1g:5-13mL.

11. The adsorbent material according to claim 1, characterized in that: In step (1), the 5A molecular sieve is immersed in a lithium salt solution at a temperature of 70-80°C for 1-5 hours.

12. The adsorbent material according to claim 1, characterized in that: The drying conditions in step (1) are: drying temperature 70-120℃, drying time 2-10h; the calcination conditions are: calcination temperature 450-600℃, calcination time 1-10h.

13. The adsorbent material according to claim 12, characterized in that: The drying conditions in step (1) are: drying temperature 80-100℃, drying time 2-5h; the calcination conditions are: calcination temperature 500-550℃, calcination time 2-6h.

14. The adsorbent material according to claim 1, characterized in that: In step (2), the vanadium salt is a soluble vanadium salt.

15. The adsorbent material according to claim 14, characterized in that: In step (2), the vanadium salt is at least one of ammonium metavanadate, sodium vanadate, vanadium oxalate, and vanadium oxalate.

16. The adsorbent material according to claim 15, characterized in that: In step (2), the vanadium salt is ammonium metavanadate.

17. The adsorbent material according to claim 1 or 14, characterized in that: The vanadium content in the vanadium salt solution in step (2) is 0.05 to 0.5 mol / L.

18. The adsorbent material according to claim 17, characterized in that: The vanadium content in the vanadium salt solution in step (2) is 0.1 to 0.3 mol / L.

19. The adsorbent material according to claim 1 or 14, characterized in that: The mass-to-volume ratio of Li-5A molecular sieve to vanadium salt solution in step (2) is 1g:20-50mL.

20. The adsorbent material according to claim 1, characterized in that: In step (2), the Li-5A molecular sieve is immersed in a vanadium salt solution for treatment at room temperature for 1 to 5 hours.

21. The adsorbent material according to claim 20, characterized in that: In step (2), the Li-5A molecular sieve is immersed in a vanadium salt solution at a temperature of 15-30°C for 1-2 hours.

22. The adsorbent material according to claim 1, characterized in that: The drying conditions in step (2) are: drying temperature 70-120℃, drying time 2-10h; the calcination conditions are: calcination temperature 450-600℃, calcination time 1-10h.

23. The adsorbent material according to claim 22, characterized in that: The drying conditions in step (2) are: drying temperature 80-100℃, drying time 2-5h; the calcination conditions are: calcination temperature 500-550℃, calcination time 2-6h.

24. The application of the adsorbent material according to any one of claims 1-23, characterized in that: Used for the adsorption and separation of low-carbon hydrocarbons in VOCs.

25. The application according to claim 24, characterized in that: Low-carbon hydrocarbons in VOCs are C2-C4 low-carbon hydrocarbons.

26. The application according to claim 25, characterized in that: The low-carbon hydrocarbons in VOCs are ethane and propane.

27. The application according to claim 26, characterized in that: Ethane is the lowest-carbon hydrocarbon among VOCs.

28. The application according to claim 24, characterized in that: The concentration of low-carbon hydrocarbons in VOCs is 100–1000 mg / m³. 3 .

29. The application according to claim 24, characterized in that: The adsorption conditions are as follows: adsorption bed temperature is 15–32℃, bed pressure is atmospheric pressure, and volume hourly space velocity is 100–500 h⁻¹. -1 .

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