Composite membrane adsorbent material, method for preparing same, and use thereof

Abstract

This invention provides a composite membrane adsorbent material, its preparation method, and its application. IRMof-16 material is uniformly dispersed and loaded onto a PVP nanofiber membrane prepared by electrospinning using a spray-doping method. The IRMof-16 material is prepared by dissolving a zinc salt in an organic solvent and dissolving p-terphenyl-4,4′-dicarboxylic acid in anhydrous ethanol. The two solutions are then mixed and subjected to a hydrothermal reaction to obtain the IRMof-16 material. The IRMof-16 material of this invention possesses a high specific surface area, suitable pore size, and abundant active sites. Combined with the high permeability of the PVP nanofiber membrane, it synergistically achieves highly efficient and selective adsorption of C4F7N decomposition products, significantly outperforming traditional adsorbent materials. IRMof-16 itself exhibits excellent hydrothermal and chemical stability, forming a weak coordination interaction with the PVP nanofiber membrane, greatly enhancing the mechanical strength and load stability of the composite membrane. The moisture resistance of PVP allows the composite membrane to withstand the humid environment of power equipment, with a capacity retention rate ≥93% after 5 cycles of adsorption, resulting in a long service life.

Description

Technical Field

[0001] This invention relates to the field of adsorption materials technology, specifically to a composite membrane adsorption material, its preparation method, and its application. Background Technology

[0002] Sulfur hexafluoride (SF6), a traditional insulating gas for power equipment, possesses excellent insulation and arc-quenching properties. However, it is also a strong greenhouse gas with a global warming potential (GWP) as high as 23,900 and an atmospheric lifetime of up to 3,200 years. To replace SF6, perfluoroisobutyronitrile (C4F7N) has emerged as a new type of environmentally friendly insulating gas. Its insulation performance is close to that of SF6, with a GWP of only 290, resulting in minimal environmental impact. It has been gradually applied in power transformers, switchgear, and other equipment.

[0003] In engineering applications, C4F7N is often mixed with gases such as CO2 and He to regulate liquefaction temperature and meet the requirements of different operating conditions. However, during long-term high-voltage operation of equipment, faults such as partial discharge and overheating can cause the C4F7N mixed gas to decompose, reacting with trace amounts of oxygen and moisture in the equipment to generate decomposition products such as hexafluoropropylene (C3F6), carbon tetrafluoride (CF4), octafluoropropane (C3F8), and carbonyl fluoride (COF2). These products not only reduce the insulation strength of the mixed gas and affect the operational stability of the equipment, but also, by developing highly efficient adsorption materials to purify the C4F7N decomposition products, it is crucial to ensure the safe and stable operation of the equipment.

[0004] Currently available adsorption materials mainly include activated carbon, zeolite molecular sieves, metal oxides, and traditional metal-organic frameworks (MOFs). Activated carbon and zeolite molecular sieves have limited specific surface areas, resulting in poor selectivity and low capacity for adsorption of C4F7N decomposition products; metal oxides (such as activated alumina) lack sufficient active sites, making their adsorption performance insufficient to meet engineering requirements; Chinese invention patent document CN119733484A discloses C5F... 10 Adsorption materials for decomposition components of C4F7N mixed gas, their preparation methods and applications: Although traditional MOF materials (such as HKUST-1) have a high specific surface area, their pore structure is poorly controllable, and their stability is insufficient under high pressure and humidity conditions, making them prone to structural collapse, which cannot meet the current application requirements for adsorbing decomposition components of C4F7N mixed gas. Summary of the Invention

[0005] The technical problem to be solved by this invention is how to provide an adsorption material that can better adsorb the decomposition components of C4F7N mixed gas.

[0006] The present invention solves the above-mentioned technical problems through the following technical means:

[0007] The first aspect of this invention provides a method for preparing a composite membrane adsorbent material, wherein IRMOF-16 material is uniformly dispersed and loaded onto a PVP nanofiber membrane prepared by electrospinning by a spray doping method; the IRMOF-16 material is prepared by the following method: zinc salt is dissolved in an organic solvent, p-terphenyl-4,4′-dicarboxylic acid is dissolved in anhydrous ethanol, and the two solutions are mixed and subjected to a hydrothermal reaction to obtain the IRMOF-16 material; the molar ratio of zinc salt to p-terphenyl-4,4′-dicarboxylic acid is 3:2.

[0008] Beneficial Effects: The IRMof-16 material of this invention possesses a high specific surface area, adaptable pore size, and abundant active sites. Combined with the high permeability of the PVP nanofiber membrane, it synergistically achieves highly efficient and selective adsorption of C4F7N decomposition products, significantly outperforming traditional adsorption materials. IRMOF-16 itself exhibits excellent hydrothermal and chemical stability, forming a weak coordination interaction with the PVP nanofiber membrane, greatly enhancing the mechanical strength and load stability of the composite membrane. The moisture resistance of PVP allows the composite membrane to withstand the humid environment of power equipment, with a capacity retention rate of ≥93% after 5 cycles of adsorption, resulting in a long service life.

[0009] Preferably, the zinc salt is zinc nitrate; and the organic solvent is N,N-dimethylformamide.

[0010] Preferably, the hydrothermal reaction temperature is 85–100°C and the hydrothermal reaction time is 12–16 h.

[0011] Preferably, the product after the hydrothermal reaction is also washed, centrifuged, and dried.

[0012] More preferably, the washing solvent is N,N-dimethylformamide and anhydrous ethanol, and the washing is performed alternately with N,N-dimethylformamide and anhydrous ethanol, and the number of washing times is 3 to 4.

[0013] More preferably, the centrifugation speed is 8500-9500 rpm and the centrifugation time is 6-7 min.

[0014] More preferably, the drying temperature is 95–105°C and the drying time is 12–14 hours.

[0015] Preferably, the PVP nanofiber membrane is prepared by the following method: dissolving PVP in a mixed solvent to prepare an electrospinning precursor solution with a mass fraction of 8-12%; and preparing the PVP nanofiber membrane by electrospinning technology.

[0016] More preferably, the mixed solvent is obtained by mixing N,N-dimethylformamide and anhydrous ethanol at a volume ratio of 3:1.

[0017] More preferably, PVP is dissolved in a mixed solvent and stirred in a water bath, wherein the water bath stirring is carried out under closed conditions at 55-65°C for 4-5 hours.

[0018] Preferably, the electrospinning conditions are as follows: voltage of 18-22kV, receiving distance of 18-22cm, feed speed of 2.0-2.5mL / h, roller speed of 160-180r / min, ambient temperature of 35-45℃, relative humidity of 35-45RH%, and spinning time of 7-8h.

[0019] Preferably, the IRMOF-16 material is mixed and stirred with isopropanol, and then ultrasonically dispersed in an ice bath to obtain a dispersion. The dispersion is loaded into a pneumatic spray gun and sprayed repeatedly in a roller carrying a PVP nanofiber membrane. After spraying, it is dried in an oven to obtain a composite membrane adsorbent material.

[0020] More preferably, the ratio of the IRMOF-16 material to isopropanol is 500 mg: 12-14 mL.

[0021] More preferably, stirring is performed at room temperature for 0.5 to 1 hour.

[0022] More preferably, the time for ultrasonic dispersion in an ice bath is 2 to 2.5 hours.

[0023] More preferably, the drying temperature is 80–85 °C and the drying time is 12–14 h.

[0024] Preferably, the mass of IRMOF-16 material loaded on each square centimeter of PVP nanofiber membrane is 2.5 to 3.0 mg.

[0025] The second aspect of the present invention provides a method for preparing the above-mentioned composite membrane adsorption material to obtain the composite membrane adsorption material.

[0026] The third aspect of the present invention provides an application of a composite membrane adsorbent material, wherein the composite membrane adsorbent material is prepared by the above-mentioned method for preparing composite membrane adsorbent material; the composite membrane adsorbent material is used to adsorb decomposition components of C4F7N mixed gas, wherein the decomposition components of C4F7N mixed gas include hexafluoropropylene and carbon tetrafluoride.

[0027] Beneficial effects: The IRMof-16 of this invention belongs to the isomorphous metal-organic framework (IRMOFs) material. Its structure is formed by Zn4O clusters and p-terphenyl-4,4′-dicarboxylic acid ligands, which have large pores and ultra-high specific surface area. This structural advantage can provide sufficient diffusion channels and adsorption sites for gas molecules, making it suitable as a porous adsorbent component for the capture and mass transfer of C4F7N mixed gas decomposition products. The PVP nanofiber membrane of this invention forms a highly porous structure through interlacing fibers, which can reduce gas mass transfer resistance. At the same time, the surface amino and carbonyl groups can form weak coordination with zinc ions on the surface of IRMof-16, improving the loading stability. Attached Figure Description

[0028] Figure 1 This is a scanning electron microscope image of the composite membrane adsorption material prepared in Example 3 of the present invention; Figure 2 These are the time-concentration adsorption curves of hexafluoropropylene for the adsorbent materials in Example 3 and Comparative Examples 1-3 of this invention; Figure 3 These are the time-concentration adsorption curves of carbon tetrafluoride for the adsorbent materials of Example 3 and Comparative Examples 1-3 of the present invention; Figure 4 This is a time-concentration adsorption curve of the adsorbent material for octafluoropropane in Example 3 and Comparative Examples 1-3 of the present invention. Figure 5 This is a time-concentration adsorption curve of the adsorbent material for carbonyl fluoride in Example 3 and Comparative Examples 1-3 of the present invention. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, 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.

[0030] Unless otherwise specified, all raw materials used in the embodiments and comparative examples of this invention are commercially available, and their specific specifications are shown in Table 1 below. To facilitate industrialization, this invention preferably adopts the route of "first preparing IRMOF-16 material—then preparing PVP nanofiber membrane—and finally preparing composite membrane adsorbent material by spray doping method," ensuring process controllability and repeatability.

[0031] Table 1. Main raw materials and specifications used in the examples and comparative examples

[0032] Example 1 This embodiment provides a method for preparing IRMof-16 material, specifically including the following steps: 1. Preparation of precursor solution and hydrothermal reaction 3.65 g of zinc nitrate hexahydrate (0.0123 mol) was dissolved in 25 mL of DMF and ultrasonically dispersed for 10 min until completely dissolved to obtain a zinc salt solution. 2.92 g of p-terphenyl-4,4′-dicarboxylic acid (0.0082 mol) was dissolved in 25 mL of anhydrous ethanol and stirred in a 60 °C water bath for 15 min until completely dissolved to obtain a ligand solution. The zinc salt solution was slowly injected into the ligand solution, and the mixture was magnetically stirred at room temperature for 30 min to form a homogeneous milky white precursor solution. The precursor solution was transferred to a 100 mL polytetrafluoroethylene-lined reactor, sealed, and placed in a 95 °C oven for a constant temperature reaction for 16 h. After the reaction was completed, the mixture was allowed to cool naturally to room temperature, precipitating a milky white solid product.

[0033] 2. Separation, washing, and solvent replacement The solid product was transferred to centrifuge tubes and centrifuged at 9000 rpm for 6 min to collect the precipitate. The product was washed four times with alternating DMF and anhydrous ethanol, and centrifuged again after each wash to remove residual ligands and impurities. Subsequently, anhydrous ethanol was used for solvent replacement, and the product was allowed to stand for 48 h with the ethanol being replaced three times to reduce the high-boiling-point DMF residue in the pores.

[0034] 3. Drying and Activation The washed solid was placed in a vacuum oven and dried under vacuum at 100℃ for 12 h to remove residual solvent from the pores, yielding a highly crystalline IRMOF-16 material. The IRMOF-16 material inherits the porous structure constructed from Zn4O clusters and dicarboxylic acid ligands. The pore size is adapted to the decomposition products of C3F6 (molecular diameter 0.58 nm), CF4 (molecular diameter 0.47 nm), octafluoropropane (molecular diameter 0.65 nm), and cyclooxygenated fluoride (molecular diameter 0.42 nm), thus fully exposing the adsorption active sites.

[0035] Example 2 This embodiment provides a method for preparing a PVP nanofiber membrane, specifically including the following steps: 1. Spinning precursor solution 7.5 g of DMF and 2.5 g of anhydrous ethanol (volume ratio 3:1) were mixed to obtain a mixed solvent. A magnetic stir bar was added to the mixture, and it was placed in a 60°C constant temperature water bath. 1 g of PVP powder was slowly added, the bottle was tightly capped, and the mixture was stirred for 4.5 h until the solution was clear, transparent, and free of particles, thus obtaining a 10% electrospinning precursor solution with a viscosity of 92 mPa·s.

[0036] 2. Electrospinning for film formation The precursor solution was injected into a 20 mL syringe, fitted with a 21G flat-tipped needle, and fixed to the injection pump of an electrospinning machine. The electrospinning parameters were set as follows: voltage 20 kV, feed rate 2.2 mL / h, needle-to-collector distance 20 cm, ambient temperature 40℃, relative humidity 40%RH%, roller collector rotation speed 170 r / min, reciprocating platform speed 900 mm / min, tin foil as the receiving substrate, and spinning time 7.5 h, forming a continuous and uniform PVP nanofiber membrane.

[0037] 3. Drying and shaping The PVP nanofiber membrane was dried in an 80℃ oven for 6 h to completely remove residual solvent, yielding the PVP nanofiber membrane substrate. This PVP nanofiber membrane exhibits a highly porous structure formed by interwoven fibers, which reduces gas mass transfer resistance. Simultaneously, the surface amino and carbonyl groups can form weak coordination interactions with zinc ions on the IRMOF-16 surface, enhancing load stability.

[0038] Example 3 This embodiment provides a method for preparing a composite membrane adsorption material, specifically including the following steps: 1. IRMOF-16 dispersion 13 mL of isopropanol was added to 500 mg of the IRMOF-16 material prepared in Example 1, and the mixture was magnetically stirred at room temperature for 0.8 h to initially disperse the material. Subsequently, the mixture was placed in an ice bath environment and ultrasonically dispersed at 750 W power for 2.2 h to obtain a uniform dispersion. The particle size of the IRMOF-16 material was measured by a laser particle size analyzer to be 60-80 nm, with no obvious agglomeration.

[0039] 2. Spray coating doping method load The dispersion was loaded into a pneumatic spray gun, and the air pressure of the spray gun was adjusted to 0.3 MPa. The PVP nanofiber membrane prepared in Example 2 was fixed on a roller collector, and the roller speed was set to 175 r / min. The membrane was sprayed repeatedly within a range of 5.5 cm vertically and 11 cm laterally from the PVP nanofiber membrane, and the number of sprays was 14 times, so that the mass of IRMOF-16 material loaded on each square centimeter of PVP nanofiber membrane was 2.8 mg / cm².

[0040] 3. Drying and pore activation After the coating is completed, the composite membrane is placed in an 82℃ oven to dry for 13 hours. This removes residual isopropanol, activates the pores of the IRMOF-16 material, and promotes the formation of weak coordination between the PVP nanofiber membrane and the IRMOF-16 material, thereby improving the structural stability of the composite membrane adsorption material.

[0041] The composite membrane adsorption material was characterized, with a focus on verifying the uniformity of loading and structural integrity. The results are as follows: according to Figure 1 It can be seen that the IRMOF-16 material in the composite membrane adsorption material is uniformly loaded on the surface of PVP nanofibers and in the gaps between the fibers, without obvious agglomeration. The PVP fibers maintain an intact interwoven structure and the porosity does not decrease significantly, which can ensure smooth gas permeation.

[0042] Combining the high specific surface area and large pore characteristics of IRMOF-16 material, the composite membrane adsorption material retains the mechanical flexibility and high permeability of PVP nanofiber membranes, while providing ample adsorption space for decomposition products such as hexafluoropropylene, carbon tetrafluoride, octafluoropropane and carbonyl fluoride through the porous structure and active sites of IRMOF-16 material, thus achieving a synergistic improvement in adsorption performance and engineering applicability.

[0043] Comparative Example 1 This comparative example provides a method for preparing a PVP film, specifically including the following steps: N,N-dimethylformamide and anhydrous ethanol were mixed at a volume ratio of 3:1 to obtain a mixed solvent. A magnetic stir bar was added, and the mixture was placed in a 60°C constant temperature water bath. 1 g of PVP powder was slowly added, and the mixture was stirred under sealed conditions for 4.5 h until the solution was clear and transparent and free of particulate impurities, yielding an electrospinning precursor solution with a mass fraction of 10% and a viscosity of 92 mPa·s. Subsequently, a continuous and uniform PVP nanofiber membrane was prepared using the same electrospinning parameters as in Example 2. The membrane was then dried in an 80°C oven for 6 h to remove residual solvent, resulting in a PVP film. This film was not loaded with any MOF material and was used only as a blank control sample.

[0044] Comparative Example 2 This comparative example provides a method for preparing HKUST-1(Zn) / PVP adsorbent material, specifically including the following steps: 1. Preparation of HKUST-1(Zn) material 1.488 g of zinc nitrate hexahydrate (0.005 mol) was dissolved in 15 mL of deionized water, and 0.525 g of trimesic acid (0.0025 mol) was dissolved in 15 mL of anhydrous ethanol. The two solutions were mixed, stirred thoroughly, and then transferred to a polytetrafluoroethylene (PTFE)-lined reactor. The reactor was hydrothermally reacted in a 60 °C oven for 15 h. After the reaction was complete, the PTFE liner was removed, and the mixture was cooled to room temperature. The reaction mixture was then transferred to centrifuge tubes and centrifuged using N₂, N₂. Dimethylformamide and anhydrous ethanol were used as washing agents. The mixture was centrifuged (9000 rpm, 5 min). The washing operation was repeated 3 times. The precipitate was then dried in a 100℃ oven for 10 h to obtain a light yellow HKUST. 1(Zn) material.

[0045] 2. Preparation of PVP nanofiber membranes The preparation method was exactly the same as in Example 2, and a PVP nanofiber membrane was obtained.

[0046] 3. Preparation of HKUST-1(Zn) / PVP adsorbent material 500 mg of HKUST-1(Zn) material was added to 13 mL of isopropanol and magnetically stirred at room temperature for 0.8 h. The mixture was then placed in an ice bath and ultrasonically dispersed at 750 W for 2 h to obtain a uniform dispersion. Using the same spraying parameters as in Example 3, the dispersion was uniformly loaded onto the surface of a PVP nanofiber membrane, with a HKUST-1(Zn) material mass of 2.5 mg / cm² loaded on each square centimeter of PVP nanofiber membrane. After spraying, the membrane was dried in an 82 ℃ oven for 13 h to remove residual solvent and activate the pores, yielding the HKUST-1(Zn) / PVP adsorbent material.

[0047] Comparative Example 3 This comparative example provides a method for preparing a composite membrane adsorbent material. The difference between this comparative example and Example 3 is that the preparation of the IRMOF-16 material is different. The molar ratio of zinc nitrate hexahydrate to p-terphenyl-4,4′-dicarboxylic acid is 2:1. Specifically, 2.92 g of p-terphenyl-4,4′-dicarboxylic acid (0.0082 mol) is replaced with 1.957 g of p-terphenyl-4,4′-dicarboxylic acid (0.00615 mol). All other operations are the same as in Example 3.

[0048] Experimental Example (1) Investigating the effect of IRMof-16 loading on CF4 adsorption performance The loading amount of IRMof-16 (mg / cm³) can be controlled by adjusting the number of spray applications. 2 The reduction in CF4 concentration was tested under the same adsorption conditions (150 kPa, 298 K, 60 days), as shown in Table 2.

[0049] Table 2. Reduction in CF4 concentration over 60 days under different IRMOF-16 loading levels.

[0050] According to Table 2, the mass of IRMOF-16 material loaded on each square centimeter of PVP nanofiber membrane is 2.5–3.0 mg / cm². 2 At this temperature, the adsorption capacity for CF4 is better, and more preferably 2.8 mg / cm³. 2 .

[0051] The optimal loading of IRMOF-16 is 2.8 mg / cm³.2 At this point, the number of active sites and the permeability of the PVP nanofiber membrane reach an optimal balance. If the loading is below 2.5 mg / cm³... 2 Insufficient active sites lead to low adsorption capacity; if it exceeds 3.0 mg / cm³, the adsorption capacity will be low. 2 Excessive IRMof-16 material can easily agglomerate and block the pores of PVP nanofiber membranes, reducing gas diffusion efficiency and causing material waste.

[0052] (2) Adsorption performance test The composite membrane adsorbent material prepared in Example 3 was cut into 2cm × 2cm pieces (corresponding to 11.2mg of IRMOF-16 material), placed in a 1.7L stainless steel adsorption chamber, sealed, and evacuated for 30 min to remove residual air. Simulated gases, including hexafluoropropylene, carbon tetrafluoride, octafluoropropane, and carbonyl fluoride, were introduced into the adsorption chamber. The initial concentrations of hexafluoropropylene, carbon tetrafluoride, octafluoropropane, and carbonyl fluoride were 545 μL / L, 1125 μL / L, 860 μL / L, and 420 μL / L, respectively. The system pressure was adjusted to 150 kPa, and the mixture was allowed to stand at room temperature for adsorption. Sampling points were set at days 5, 10, 15, 18, and 60, and gas samples were collected for component analysis. Simultaneously, the composite membrane adsorbent material prepared in Example 3 was replaced with the material prepared in Comparative Examples 1-3, and the experimental methods were the same as described above, with gas samples collected for component analysis.

[0053] Gas chromatography-mass spectrometry (GC-MS) was used for quantitative analysis of the sampled gas, with concentration reduction, removal rate, and adsorption capacity per unit mass as evaluation indicators. The removal rate was calculated using the following formula: Removal rate (%) = (C0...) C t ) / C0×100%, where C0 is the initial concentration, C t Let t be the concentration at time t.

[0054] The adsorption capacity per unit mass can be calculated using the gas law: q = (ΔC × 10⁻⁶) -6 × P × V × M) / (R × T × m); where q is the adsorption capacity per unit mass (mg / g), ΔC is the concentration reduction (μL / L), P is the pressure (Pa), V is the volume of the adsorption chamber (m³), R is the gas constant (8.314 J / (mol·K)), T is the temperature (K), M is the molar mass of the component to be adsorbed (g / mol), and m is the mass of IRMOF-16 in the adsorbent material (g).

[0055] The adsorption results are shown in Table 3, and the details are as follows: Table 3. Time-concentration data for adsorption of C3F6 and CF4 in the Examples and Comparative Examples

[0056] According to Table 3 and Figure 2 It can be seen that the composite membrane adsorbent material prepared in Example 3 has a fast adsorption rate for hexafluoropropylene. On the 15th day, the concentration of hexafluoropropylene drops to about 50 μL / L (removal rate of about 90.8%), and on the 20th day, it drops to below 2 μL / L. After 60 days, it approaches 0, which is significantly better than the materials prepared in Comparative Examples 1-3.

[0057] According to Table 3 and Figure 3 As shown, the composite membrane adsorbent material prepared in Example 3 exhibited a continuous adsorption capacity for carbon tetrafluoride. Within 60 days, the concentration of carbon tetrafluoride decreased from 1125 μL / L to 705 μL / L, a reduction of 420 μL / L, corresponding to a removal rate of approximately 37.3%, which translates to an adsorption capacity of approximately 95 mg / g. It can effectively capture low concentrations of carbon tetrafluoride for a long period of time.

[0058] The PVP film prepared in Comparative Example 1 showed a significantly smaller reduction in the concentration of hexafluoropropylene and carbon tetrafluoride, indicating that the introduction of IRMOF-16 material significantly improved the reduction in the concentration of hexafluoropropylene and carbon tetrafluoride. This suggests that the pores of IRMOF-16 material allow hexafluoropropylene and carbon tetrafluoride to pass through smoothly, and that hexafluoropropylene and carbon tetrafluoride are adsorbed through adsorption active sites.

[0059] The HKUST-1(Zn) / PVP adsorbent material prepared in Comparative Example 2 exhibited a slow adsorption rate and high equilibrium concentration for hexafluoropropylene and carbon tetrafluoride, with an overall purification effect far lower than that in Example 3. This indicates that under the same zinc source and pyromellitic acid ligand conditions, the pore structure, specific surface area, and number of active sites of the HKUST-1(Zn) material cannot meet the requirements for high-efficiency adsorption.

[0060] Compared to Example 3, the composite membrane adsorbent material prepared in Comparative Example 3 only differed in the molar ratio of zinc nitrate hexahydrate to p-terphenyl-4,4′-dicarboxylic acid during the preparation of IRMOF-16. Its adsorption performance was lower than that of Example 3, indicating that the crystal structure, pore development, and effective active site exposure of IRMOF-16 formed under the current preferred ratio are more conducive to the adsorption of target decomposition products. However, when the ratio of metal source to organic ligand deviates from the preferred range, the pore structure integrity and post-loading dispersibility of the obtained material decrease, resulting in a weakening of the overall adsorption performance of the composite membrane.

[0061] Table 4. Time-concentration data for adsorption of C3F8 and COF2 in the Examples and Comparative Examples

[0062] According to Table 4 and Figure 4As shown, the composite membrane adsorbent material prepared in Example 3 exhibited good adsorption capacity for octafluoropropane. Its concentration decreased from 860 μL / L to 430 μL / L within 60 days, a reduction of 430 μL / L, corresponding to a removal rate of approximately 50.0%. In contrast, the concentration reduction in Comparative Examples 1-3 was significantly smaller, with Comparative Example 1 showing the worst performance. While Comparative Examples 2 and 3 showed some adsorption capacity, their overall purification effects were significantly lower than those in Example 3, indicating that the introduction of IRMof-16 significantly improved the adsorption capacity for octafluoropropane.

[0063] According to Table 4 and Figure 5 As shown, the composite membrane adsorbent material prepared in Example 3 exhibits superior adsorption performance for carbonyl fluoride. Within 60 days, its concentration decreased from 420 μL / L to 35 μL / L, a reduction of 385 μL / L, corresponding to a removal rate of approximately 91.7%. In contrast, the materials in Comparative Examples 1-3 showed significantly lower removal capacity for carbonyl fluoride, indicating that the composite membrane adsorbent material of this invention has a significant advantage in treating polar decomposition products.

[0064] Table 5. Summary of 60-day adsorption results for C3F6, CF4, C3F8 and COF2 in Example 3.

[0065] As shown in Table 5, the composite membrane adsorbent material prepared in Example 3 exhibits adsorption activity for C3F6, CF4, C3F8, and COF2, but shows significantly different adsorption characteristics for different decomposition components. Specifically, the removal rates for C3F6 and COF2 reached 99.9% and 91.7%, respectively, indicating that the composite membrane of this invention has a significant adsorption advantage for unsaturated and polar decomposition components. The removal rates for C3F8 and CF4 were 50.0% and 37.3%, respectively, indicating that the composite membrane of this invention also has a continuous purification capacity for relatively difficult-to-adsorb components. Further analysis of the adsorption capacity per unit mass shows that the adsorption capacities for C3F6 and C3F8 reached 750.67 mg / g and 742.97 mg / g, respectively, indicating that the composite membrane of this invention has a high mass carrying capacity for high molar mass fluorine-containing decomposition components.

[0066] In summary, the composite membrane prepared in Example 3 exhibits significantly better adsorption rates, removal rates, and adsorption capacities for hexafluoropropylene, carbon tetrafluoride, octafluoropropane, and carbonyl fluoride than the materials prepared in Comparative Examples 1-3, fully demonstrating the outstanding advantages of the material of this invention in terms of structural design and adsorption performance.

[0067] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing a composite membrane adsorption material, characterized in that, IRMOF-16 material was uniformly dispersed and loaded onto a PVP nanofiber membrane prepared by electrospinning by spray doping. The IRMOF-16 material was prepared by dissolving a zinc salt in an organic solvent and dissolving p-terphenyl-4,4′-dicarboxylic acid in anhydrous ethanol. The two solutions were then mixed and subjected to a hydrothermal reaction to obtain the IRMOF-16 material. The molar ratio of zinc salt to p-terphenyl-4,4′-dicarboxylic acid was 3:

2.

2. The method for preparing the composite membrane adsorption material according to claim 1, characterized in that, The zinc salt is zinc nitrate, and the organic solvent is N,N-dimethylformamide.

3. The method for preparing the composite membrane adsorption material according to claim 1, characterized in that, The hydrothermal reaction temperature is 85–100℃, and the hydrothermal reaction time is 12–16 hours.

4. The method for preparing the composite membrane adsorption material according to claim 1, characterized in that, It also includes washing, centrifuging and drying the products after the hydrothermal reaction.

5. The method for preparing the composite membrane adsorption material according to claim 1, characterized in that, PVP nanofiber membranes are prepared by dissolving PVP in a mixed solvent to prepare an electrospinning precursor solution with a mass fraction of 8-12%; and then preparing PVP nanofiber membranes using electrospinning technology.

6. The method for preparing the composite membrane adsorption material according to claim 5, characterized in that, The electrospinning conditions are as follows: voltage 18-22kV, receiving distance 18-22cm, feed speed 2.0-2.5mL / h, roller speed 160-180r / min, ambient temperature 35-45℃, relative humidity 35-45RH%, and spinning time 7-8h.

7. The method for preparing the composite membrane adsorption material according to claim 1, characterized in that, IRMOF-16 material was mixed with isopropanol and then ultrasonically dispersed in an ice bath to obtain a dispersion. The dispersion was loaded into a pneumatic spray gun and sprayed repeatedly in a roller carrying a PVP nanofiber membrane. After spraying, it was dried in an oven to obtain a composite membrane adsorbent material.

8. The method for preparing the composite membrane adsorbent material according to claim 1 or 7, characterized in that, The mass of IRMof-16 material loaded on each square centimeter of PVP nanofiber membrane is 2.5–3.0 mg.

9. A method for preparing a composite membrane adsorbent material according to any one of claims 1-8.

10. An application of a composite membrane adsorption material, characterized in that, The composite membrane adsorbent material is prepared by the method described in any one of claims 1-8; the composite membrane adsorbent material is used to adsorb the decomposition components of the C4F7N mixed gas, which include hexafluoropropylene, carbon tetrafluoride, octafluoropropane and carbonyl fluoride.

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