A defect type material for separating fluorine-containing electronic special gas and a preparation method thereof

Abstract

This invention discloses a defective material for the separation of fluorine-containing electronic specialty gases and its preparation method. Using monodisperse PSD microspheres as a carrier, an HKUST-1 MOF shell is grown in situ on its surface, and acetic acid is introduced to regulate the structural defects of the MOF, thus preparing a PSD@HKUST-1-AcOH defective composite material. The prepared composite material PSD@HKUST-1-AcOH possesses a controllable defect structure, abundant adsorption sites, and an tunable pore structure, exhibiting excellent separation performance for fluorine-containing electronic specialty gases, enabling efficient recovery and purification of these gases. This invention features a simple process and novel structural design. The precise preparation of the defective structure through acetic acid regulation solves the problem of balancing adsorption performance and structural stability in traditional MOF materials, showing promising application prospects in the fields of electronic chemical purification and waste gas treatment.

Description

Technical Field

[0001] This invention belongs to the field of gas separation and purification technology, specifically relating to a defective material for the separation of fluorine-containing electronic special gases and its preparation method. Background Technology

[0002] Fluorinated electronic specialty gases SF6 and CF4 are indispensable core materials in high-tech fields such as semiconductor manufacturing and flat panel displays. They are widely used in key processes such as chip etching, device cleaning, and thin film deposition, and their purity directly affects the performance and yield of electronic devices. At the same time, these gases have a strong greenhouse effect, making their efficient separation and recovery both an inevitable requirement for industry development and an important measure for environmental protection. Currently, the separation and purification technology of fluorinated electronic specialty gases still faces many bottlenecks, making it difficult to meet the industry's application requirements of high precision, low energy consumption, and high stability.

[0003] HKUST-1, a typical MOF material, exhibits excellent adsorption selectivity for fluorinated specialty gases such as SF6 and CF4 due to its unique pore structure and abundant active sites, making it a research hotspot for fluorinated specialty gas separation materials. However, pure HKUST-1 suffers from poor mechanical stability and is prone to aggregation, severely limiting its industrial promotion and application. Polystyrene-divinylbenzene microspheres (PSD) possess a regular pore structure, excellent mechanical strength, and good dispersibility, and their preparation process is mature and cost-effective. Using PSD as a carrier, a composite material can be constructed by combining it with HKUST-1 through in-situ growth. This fully leverages the structural support of PSD microspheres and the high-efficiency adsorption performance of HKUST-1, effectively solving the application bottleneck of poor mechanical stability and easy aggregation of pure MOF materials, and achieving a synergistic improvement in separation performance and structural stability.

[0004] A well-designed defect structure can significantly increase the number of active adsorption sites and optimize pore connectivity in materials, thereby greatly improving the adsorption capacity and separation selectivity of materials for fluorine-containing electronic specialty gases. Therefore, developing a defect-type MOF-based composite material that can easily control the defect structure, increase active adsorption sites, has a simple process, and exhibits excellent performance is of significant industrial application value and environmental importance. This would solve the current technical challenges in the separation of fluorine-containing electronic specialty gases, meet the needs of industries such as semiconductors for high-precision separation and efficient recovery of specialty gases, and satisfy these needs. Summary of the Invention

[0005] The purpose of this invention is to provide a defective material for the separation of fluorine-containing electronic special gases and its preparation method. Monodisperse polystyrene-divinylbenzene microspheres (PSD) are prepared by dispersion polymerization combined with a two-step swelling method as a carrier. Copper nitrate and trimesic acid are selected as reaction raw materials. An HKUST-1 shell is introduced through in-situ growth, and acetic acid is introduced to regulate the defects, so as to solve the problems of insufficient adsorption sites and limited separation efficiency of existing materials.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] In a first aspect, the present invention provides a defective material PSD@HKUST-1-AcOH for the separation of fluorine-containing electronic special gases. Using polystyrene-divinylbenzene microspheres as a carrier, an HKUST-1 MOF shell is grown in situ on the microspheres, and acetic acid is introduced to regulate the structural defects of the MOF, thereby preparing a series of defective composite materials of PSD@HKUST-1-AcOH.

[0008] Secondly, the present invention provides a method for preparing the above-mentioned defective material PSD@HKUST-1-AcOH, comprising the following steps:

[0009] (1) Polyvinylpyrrolidone was dissolved in anhydrous ethanol to obtain a first solution, and azobisisobutyronitrile was dissolved in styrene to obtain a second solution; the first solution and the second solution were mixed and stirred at 65-75°C for 18-30 h under nitrogen; after the reaction was completed, the mixture was cooled, centrifuged, washed and dried to obtain polystyrene seed microspheres;

[0010] (2) Polystyrene seed microspheres and dibutyl phthalate were dispersed in sodium dodecyl sulfate aqueous solution, and the above solutions were mixed and swollen at 25-35°C for 18-30 h; then benzoyl peroxide, divinylbenzene and styrene were dispersed in sodium dodecyl sulfate aqueous solution and added, and swollen at 25-35°C for 18-30 h.

[0011] (3) Add a polyvinyl alcohol solution with a mass concentration of 8-12 wt% to the reaction system of step (2), and stir the reaction at 65-75℃ for 18-30 h under nitrogen. After the reaction is completed, PSD microspheres are obtained by centrifugation, washing and drying.

[0012] (4) PSD microspheres, copper nitrate trihydrate and polyvinylpyrrolidone were dissolved in methanol to obtain solution A, and trimesic acid and acetic acid were dissolved in methanol to obtain solution B. The two solutions were mixed and reacted at 10~40℃ for 20~28 h. The reaction product was centrifuged, washed and dried to obtain defective composite material PSD@HKUST-1-AcOH.

[0013] Furthermore, in step (1), the mass ratio of polyvinylpyrrolidone, anhydrous ethanol, azobisisobutyronitrile and styrene is (1-2):(70-90):(0.3-0.6):(10-20).

[0014] Furthermore, in step (2), the ratio of polystyrene seed microspheres to dibutyl phthalate, benzoyl peroxide, divinylbenzene, styrene and polyvinyl alcohol solution is 1~2g: 3~6mL: 0.5~1g: 3~6mL: 2~4mL: 20~30mL.

[0015] Furthermore, in step (2), the mass concentration of the sodium dodecyl sulfate aqueous solution is 0.30–0.45 wt%.

[0016] Furthermore, in step (4), the ratio of PSD microspheres, copper nitrate trihydrate, polyvinylpyrrolidone, pyromellitic acid and acetic acid is 1g:8-10g:4-5g:3-5g:100-150mL.

[0017] Thirdly, the present invention provides an adsorbent material comprising the aforementioned defective material PSD@HKUST-1-AcOH.

[0018] Fourthly, the present invention provides the application of the above-mentioned defective material PSD@HKUST-1-AcOH or the above-mentioned adsorbent material in the adsorption and / or separation of fluorine-containing electronic special gases.

[0019] Furthermore, the fluorine-containing electronic specialty gas is SF6.

[0020] Fifthly, the present invention provides the application of the aforementioned defective material PSD@HKUST-1-AcOH or the aforementioned adsorbent material in the separation of SF6 / N2.

[0021] The defective composite material prepared in this invention uses PSD as a carrier to provide structural support and generates abundant defect adsorption sites by regulating HKUST-1 with acetic acid. The degree of defect can be flexibly adjusted according to separation requirements, significantly improving the adsorption capacity and separation selectivity for fluorine-containing electronic specialty gases, and solving the problems of insufficient adsorption sites and limited separation efficiency of traditional materials. The process of this invention is simple and highly controllable, and the prepared material has a stable structure and excellent adsorption and separation performance. It can be widely used in the separation and recovery of specialty gases in the semiconductor industry, and has important industrial application value and environmental significance.

[0022] The beneficial effects of this invention are as follows:

[0023] (1) PSD@HKUST-1-AcOH defect-type composite material was prepared by using dispersion polymerization combined with two-step swelling method, in-situ growth process and acetic acid to regulate defects. The preparation method is simple, highly controllable, and the reaction conditions are mild. It does not require complex equipment, which is convenient for industrial scale-up production and reduces the cost of practical application.

[0024] (2) By introducing abundant crystal defects through acetic acid regulation, the active adsorption sites are significantly increased and the pore connectivity is optimized, so as to achieve high capacity adsorption and high selective separation of fluorine-containing electronic special gases such as SF6, effectively solving the problems of insufficient adsorption sites and difficulty in improving adsorption capacity and selectivity of traditional MOF materials.

[0025] (3) Applying PSD@HKUST-1-AcOH defective composite material to the field of fluorine-containing electronic special gas separation overcomes the disadvantages of limited adsorption sites and low separation efficiency of conventional MOF-based materials. The resulting material has a stable structure, excellent porosity, and good recyclability, which can reduce actual losses during application and meet the stringent requirements of special gas recovery and purification in the semiconductor industry. Attached Figure Description

[0026] Figure 1 These are the XRD patterns of PSD@HKUST-1-20 and PSD@HKUST-1-AcOH of the present invention.

[0027] Figure 2 These are the SEM and SEM-EDS images of the PSD@HKUST-1-20 of this invention.

[0028] Figure 3 These are the EPR, XANES, and EXAFS spectra of PSD@HKUST-1-20 and PSD@HKUST-1-AcOH of the present invention.

[0029] Figure 4 The adsorption-desorption curves (a, b) and pore size distribution (c, d) of PSD@HKUST-1-20 and PSD@HKUST-1-AcOH of the present invention at 77K are shown.

[0030] Figure 5 These are the single-component adsorption curves of PSD@HKUST-1-20 and PSD@HKUST-1-AcOH of the present invention at 298K for (a) N2, (b) CF4 and (c) SF6.

[0031] Figure 6 The present invention describes the separation selectivity of PSD@HKUST-1-20 and PSD@HKUST-1-AcOH for (a, b) CF4 / N2 and (c, d) SF6 / N2.

[0032] Figure 7 This is a GC separation curve of PSD@HKUST-1-20 and PSD@HKUST-1-AcOH (a, b)CF4 / N2 and (c, d)SF6 / N2 of the present invention.

[0033] Figure 8This is the XRD pattern of the PSD@HKUST-1-AcOH of the present invention after GC cycle testing and three months of storage. Detailed Implementation

[0034] To further understand the present invention, the embodiments of the present invention are described below in conjunction with the accompanying drawings. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, and are not intended to limit the scope of the claims of the present invention.

[0035] In the following embodiments, the polyvinylpyrrolidone is of type K30 with a molecular weight of approximately 40,000-60,000; the polyvinyl alcohol is of type 1788 with an average degree of polymerization of 1650-1850 and a degree of alcoholysis of approximately 87.0-89.0%.

[0036] Comparative Example 1: PSD Microspheres

[0037] 1.5 g of polyvinylpyrrolidone was weighed and added to 80 g of anhydrous ethanol, and 0.44 g of azobisisobutyronitrile was added to 15 g of styrene. Both solutions were dissolved separately by sonication, and then added together to a three-necked flask. N2 was bubbled through the flask for 15 min. The temperature was then raised to 70 °C, and the reaction was mechanically stirred at 300 rpm for 24 h. After the reaction was complete, the mixture was cooled to room temperature and centrifuged. The resulting precipitate was washed three times each with anhydrous ethanol and water (2500 rpm), and then dried in a vacuum drying oven at room temperature to obtain polystyrene (PS) seed microspheres.

[0038] In a three-necked flask, 1.3 g of PS seed microspheres were added and ultrasonically dispersed with 50 mL of sodium dodecyl sulfate aqueous solution (0.375 wt%). 5 mL of dibutyl phthalate was added to 100 mL of sodium dodecyl sulfate aqueous solution (0.375 wt%), ultrasonically dispersed, and then added to the three-necked flask with stirring at 300 rpm. The mixture swelled at 30 °C for 24 h. Separately, 0.6 g of benzoyl peroxide, 5 mL of divinylbenzene (DVB), and 3 mL of styrene were added to 150 mL of sodium dodecyl sulfate aqueous solution (0.25 wt%), ultrasonically dispersed, and then added to the three-necked flask with stirring at 300 rpm. The mixture swelled at 30 °C for 24 h. Subsequently, 25 mL of polyvinyl alcohol aqueous solution (10 wt%) was added to the three-necked flask, and the mixture was purged with N2 for 30 min. The stirring speed was adjusted to 120 rpm, and the reaction was carried out at 70 °C for 24 h. The product was washed with anhydrous ethanol and ultrapure water at 2000 rpm and dried under vacuum at room temperature to obtain PSD microspheres.

[0039] Comparative Example 2

[0040] 0.4 g of PSD microspheres (prepared in Comparative Example 1), 3.6 g of copper nitrate trihydrate, and 1.7 g of polyvinylpyrrolidone were ultrasonically dissolved in 200 mL of methanol to obtain solution A; separately, 1.72 g of trimesic acid was ultrasonically dissolved in 200 mL of methanol to obtain solution B. Solutions A and B were mixed and reacted with stirring at 20 °C for 24 h. The product was washed three times by centrifugation with methanol at 6000 rpm and dried under vacuum at 70 °C to obtain PSD@HKUST-1-20.

[0041] Example 1

[0042] 0.4 g of PSD microspheres, 3.6 g of copper nitrate trihydrate, and 1.7 g of polyvinylpyrrolidone were dissolved in 200 mL of methanol to obtain solution A. Separately, 1.72 g of trimesic acid was dissolved in 200 mL of methanol, and 50 mL of acetic acid was added. The mixture was then sonicated to obtain solution B. Solutions A and B were mixed thoroughly and reacted at 20 °C for 24 h with stirring. The product was washed three times with methanol by centrifugation at 6000 rpm and dried under vacuum at 70 °C to obtain PSD@HKUST-1-AcOH.

[0043] Figure 1 The crystal structures of PSD@HKUST-1-20 and PSD@HKUST-1-AcOH were characterized, indicating that HKUST-1 was successfully grown on the surface of PSD microspheres.

[0044] Figure 2 The morphological characterization of PSD@HKUST-1-20 shows that HKUST-1 is uniformly covered on the surface of PSD microspheres.

[0045] Figure 3 The defect characterization of PSD@HKUST-1-20 and PSD@HKUST-1-AcOH shows that the acetic acid modification successfully introduced controllable coordination defects while maintaining the overall structure of the material.

[0046] In summary, after modification with acetic acid, the morphology of the material remained intact, but the crystal structure exhibited reduced order and local distortion, and unsaturated coordination sites were successfully introduced.

[0047] Figure 4 The N2 adsorption-desorption curves and pore size distributions of PSD@HKUST-1-20 and PSD@HKUST-1-AcOH at 77 K are shown. The specific surface areas of PSD@HKUST-1-20 and PSD@HKUST-1-AcOH are 145 m² / g. 2 / g and 136 m 2 / g. The acetic acid-modified sample PSD@HKUST-1-AcOH showed a significant increase in N2 adsorption in the low-pressure region, and the pore size distribution changed from a single-peak distribution of the unmodified sample to a multi-peak distribution containing 10-18 Å defect pores.

[0048] Figure 5 The adsorption capacities of PSD@HKUST-1-20 and PSD@HKUST-1-AcOH for N2, CF4, and SF6 at 298 K are shown. Compared to PSD@HKUST-1-20, PSD@HKUST-1-AcOH shows a significant increase in the single-component adsorption capacity for SF6, while its adsorption capacity for CF4 decreases.

[0049] Figure 6 The potential separation capabilities of PSD@HKUST-1-20 and PSD@HKUST-1-AcOH for CF4 / N2 (v / v=70 / 30) and SF6 / N2 (v / v=70 / 30) were investigated. The results showed that PSD@HKUST-1-AcOH significantly improved the separation selectivity for SF6 / N2, while decreasing the separation selectivity for CF4 / N2.

[0050] PSD@HKUST-1-20 and PSD@HKUST-1-AcOH materials were packed into separation columns, respectively. The separation test conditions for the CF4 / N2 (v / v=70 / 30) mixed gas were set as follows: column temperature 30℃, mixed gas flow rate 50 mL / min; the separation test conditions for the SF6 / N2 (v / v=70 / 30) mixed gas were set as follows: column temperature 40℃, mixed gas flow rate 90 mL / min. The separation effect of each material on the two mixed gases was detected and recorded using gas chromatography, and the differences in separation performance between PSD@HKUST-1-20 and PSD@HKUST-1-AcOH were compared and analyzed. The results are as follows: Figure 7 As shown, PSD@HKUST-1-AcOH exhibits excellent separation performance for SF6 / N2, but its separation performance for CF4 / N2 decreases after acetic acid treatment.

[0051] After the above separation test was completed, the material was recovered and placed in a vacuum drying oven and heated at 90°C for 2 hours. The treated material was then repacked into the separation column, and the above separation test steps were repeated for a total of 3 cycles. The results were detected by gas chromatography. The results showed that after 3 cycles, there were no significant changes in the peak shape, resolution, and retention time. The material still maintained excellent separation performance and had good cycle stability.

[0052] Figure 8The XRD pattern of PSD@HKUST-1-AcOH after three GC cycles and three months of storage shows that PSD@HKUST-1-0 has excellent structural stability and recyclability.

[0053] The above description is only a preferred embodiment of the present invention. All equivalent changes and modifications made within the scope of the claims of the present invention should be included in the scope of the present invention.

Claims

1. A defective material PSD@HKUST-1-AcOH for the separation of fluorine-containing electronic special gases, characterized in that: Using polystyrene-divinylbenzene microspheres as a carrier, HKUST-1 MOF shells were grown in situ on them, and acetic acid was introduced to regulate the structural defects of the MOF, thus preparing a series of defect-type composite materials of PSD@HKUST-1-AcOH.

2. The method for preparing the defective material PSD@HKUST-1-AcOH as described in claim 1, characterized in that: Includes the following steps: (1) Polyvinylpyrrolidone was dissolved in anhydrous ethanol to obtain a first solution, and azobisisobutyronitrile was dissolved in styrene to obtain a second solution; the first solution and the second solution were mixed and stirred at 65-75°C for 18-30 h under nitrogen; after the reaction was completed, the mixture was cooled, centrifuged, washed and dried to obtain polystyrene seed microspheres; (2) Polystyrene seed microspheres and dibutyl phthalate were dispersed in sodium dodecyl sulfate aqueous solution, and the above solutions were mixed and swollen at 25-35°C for 18-30 h; then benzoyl peroxide, divinylbenzene and styrene were dispersed in sodium dodecyl sulfate aqueous solution and added, and swollen at 25-35°C for 18-30 h. (3) Add a polyvinyl alcohol solution with a mass concentration of 8-12 wt% to the reaction system of step (2), and stir the reaction at 65-75℃ for 18-30 h under nitrogen. After the reaction is completed, PSD microspheres are obtained by centrifugation, washing and drying. (4) PSD microspheres, copper nitrate trihydrate and polyvinylpyrrolidone were dissolved in methanol to obtain solution A, and trimesic acid and acetic acid were dissolved in methanol to obtain solution B. The two solutions were mixed and reacted at 10~40℃ for 20~28 h. The reaction product was centrifuged, washed and dried to obtain defective composite material PSD@HKUST-1-AcOH.

3. The preparation method according to claim 2, characterized in that: In step (1), the mass ratio of polyvinylpyrrolidone, anhydrous ethanol, azobisisobutyronitrile and styrene is (1-2): (70-90): (0.3-0.6): (10-20).

4. The preparation method according to claim 2, characterized in that: In step (2), the ratio of polystyrene seed microspheres to dibutyl phthalate, benzoyl peroxide, divinylbenzene, styrene and polyvinyl alcohol solution is 1~2g: 3~6mL: 0.5~1g: 3~6mL: 2~4mL: 20~30mL.

5. The preparation method according to claim 2, characterized in that: The mass concentration of sodium dodecyl sulfate aqueous solution in step (2) is 0.30–0.45 wt%.

6. The preparation method according to claim 2, characterized in that: In step (4), the ratio of PSD microspheres, copper nitrate trihydrate, polyvinylpyrrolidone, trimesic acid and acetic acid is 1g:8-10g:4-5g:3-5g:100-150mL.

7. An adsorbent material, characterized in that: It contains the defective material PSD@HKUST-1-AcOH as described in claim 1.

8. The application of the defective material PSD@HKUST-1-AcOH as described in claim 1 or the adsorbent material as described in claim 7 in the adsorption and / or separation of fluorine-containing electronic specialty gases.

9. The application according to claim 8, characterized in that: The fluorine-containing electronic specialty gas is SF6.

10. The application of the defective material PSD@HKUST-1-AcOH as described in claim 1 or the adsorbent material as described in claim 7 in the separation of SF6 / N2.

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