Graft modified amidoxime copolymer resin porous microspheres, and preparation method and application thereof
By preparing and modifying copolymer resin microspheres, the risks of nuclear diffusion and the radiation resistance of adsorbent materials in the traditional method for preparing 99Mo were solved, achieving efficient adsorption of Mo(VI) and improving the mechanical stability and adsorption capacity of the resin.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SHANGHAI INSTITUTE OF APPLIED PHYSICS CHINESE ACADEMY OF SCIENCES
- Filing Date
- 2026-03-24
- Publication Date
- 2026-06-19
Smart Images
Figure CN122230698A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of radionuclide separation and adsorption materials technology, specifically to a graft-modified amine oxime copolymer resin porous microsphere, its preparation method, and its application. Background Technology
[0002] Technetium-99m ( 99m Tc is the most commonly used radionuclide in nuclear medicine. Currently 99m Tc is mainly produced by molybdenum-99 ( 99 Molybdenum technetium generator using Mo as raw material 99m Tc obtained. And 99 In the preparation methods of Mo, the traditional method involves using highly enriched uranium. 235 U-fission is obtained. This method yields... 99 Mo exhibits high specific activity, therefore, although the adsorption capacity of traditional commercial alumina is only 2-20 mg / g, it can still meet practical application requirements. However, traditional preparation methods pose risks of nuclear proliferation and reactor aging. Using a non-fission preparation method, namely the neutron activation method, can avoid the technical problems of traditional methods; however, the resulting... 99 Mo has a low specific activity, which means that traditional commercial alumina cannot meet the requirements of practical applications. Therefore, it is necessary to use column adsorbents with high Mo ion adsorption capacity.
[0003] Among conventional adsorbent materials, chitosan, a natural polymer, stands out due to its polysaccharide composition, which is rich in amino and hydroxyl groups as active groups. This results in high adsorption performance, low cost, and biodegradability. For example, existing literature 1 (Brion-Roby R, Gagnon J, Nosrati S, et al. Adsorption and desorption of molybdenum (VI) in contaminated water using a chitosansorbent[J]. Journal of Water Process Engineering, 2018, 23:13-19.) utilizes chitosan through thermal cross-linking to form an insoluble chitosan adsorbent, achieving an adsorption capacity of 123 mg / g for Mo(VI). However, when this technical solution is applied to a molybdenum technetium generator, there is a technical problem that it is not practical. The specific reason is that, according to reference 2 (Wei Tuantuan, Wang Huirui, Sun Yanxiaofan, et al. Research progress on the degradation of polysaccharides by gamma ray irradiation [J]. Journal of Food Safety and Quality Testing, 2023, 14(02): 1-8.), chitosan undergoes degradation under irradiation conditions, that is, it does not have radiation resistance stability.
[0004] In conventional adsorbent materials, resins not only have the characteristics of tunable pore structure and abundant surface functional groups, but also the problem of lack of radiation resistance can be solved by modifying the resin. For example, existing literature 3 ([1] Hasan S . Preparation of chitosan-based microporous composite material and its applications: 13 / 424289[P]. US8911695[2026-01-09].) prepared a microporous composite resin MPCM by crosslinking chitosan and glutaraldehyde, which makes the resin have radiation resistance, high temperature resistance and no physical degradation. However, the resin obtained by this technical solution only interacts with molybdenum ions through amino groups, that is, it has a single functional group, which leads to the lack of multifunctional group synergistic effect, that is, chelation effect. Summary of the Invention
[0005] The purpose of this invention is to provide a graft-modified amylopyridine copolymer resin porous microsphere, its preparation method, and its application. The basic principle of this invention is as follows: First, via suspension polymerization, acrylonitrile (AN), methyl methacrylate (MMA), and styrene (St) are used as comonomers, combined with a porogen and a crosslinking agent to construct resin microspheres ANMA with a hierarchical porous structure and high stability in one step. Then, through amylopyridine modification, the cyano-C≡N groups on the ANMA microspheres are converted into amylopyridine groups -C(NH₂)=N-OH, thereby introducing adsorption sites with specific chelating ability for Mo(VI) ions. Finally, through graft modification with polyethyleneimine (PEI), PEI segments rich in amino-NH₂ / -NH⁻ are further introduced onto the surface of the amylopyridine microspheres ANMA, constructing bifunctional adsorption sites with synergistic effects of amylopyridine groups and amino / imino groups, significantly improving the adsorption capacity for Mo(VI).
[0006] The main functions of each component in the technical solution are as follows: ANMA microspheres serve as the basic framework, with interconnected micropores and mesopores providing abundant mass transfer channels and accessible specific surface area. The amine oxime group serves as the core adsorption site, and the N and O atoms in the structure can form stable coordination bonds with Mo(VI), achieving highly selective adsorption of Mo(VI). Polyethylene imine (PEI) segments serve as synergistic adsorption and structural reinforcement units, with technical effects manifested in two aspects: 1. A large number of amino / imino groups on the segments have an adsorption effect on Mo(VI) ions; 2. The PEI chains and the AOMA skeleton are chemically bonded, enhancing the overall network structure stability and mechanical strength of the resin.
[0007] To achieve the above-mentioned objectives, the technical solution adopted by this invention is as follows: A graft-modified amylopyridine-oxime-modified copolymer resin porous microsphere is prepared by using acrylonitrile, methyl methacrylate, and styrene as comonomers, divinylbenzene as a crosslinking agent, and azobisisobutyronitrile as an initiator. The copolymer resin microspheres ANMA are formed by suspension polymerization, followed by amylopyridine oxime-modification reaction with hydroxylamine hydrochloride solution to obtain amylopyridine-oxime-modified microspheres AOMA. Finally, the microspheres are modified by ethylenediamine amination, glutaraldehyde activation, and polyethyleneimine (PEI) grafting to obtain graft-modified amylopyridine-oxime-modified copolymer resin porous microspheres AOMA-PEI. AOMA-PEI possesses characteristic functional groups of amylopyridine-oxime group -C(NH2)=N-OH and aliphatic amine CN. The microstructure of AOMA-PEI is a micron-sized spherical structure with a specific surface area of 93-99 m². 2 / g, mesopore volume data are 0.30-0.40 cm³. 3 / g; AOMA-PEI has a strength of 31-35 MPa and a tensile stress of 55-60 MPa.
[0008] A method for preparing porous microspheres of graft-modified amine oxime copolymer resin includes the following steps: Step 1, Synthesis of ANMA Microspheres: First, acrylonitrile, methyl methacrylate, and styrene are used as raw materials; toluene, cyclohexanol, and tetrahydrofuran are used as porogens; divinylbenzene is used as a crosslinking agent; azobisisobutyronitrile (AIBN) is used as an initiator; and polyvinyl alcohol is used as an aqueous dispersant. Acrylonitrile, methyl methacrylate, styrene, divinylbenzene, AIBN, toluene, cyclohexanol, and tetrahydrofuran are mixed to obtain an oil phase. Simultaneously, polyvinyl alcohol and water are mixed to obtain an aqueous phase. Then, the oil phase and aqueous phase are mixed and stirred. After stirring, the porogens are removed by washing and extraction. Finally, after displacement, the mixture is freeze-dried under vacuum to obtain acrylonitrile / methyl methacrylate copolymer resin porous microspheres, abbreviated as ANMA. In step 1, the mass ratio of acrylonitrile, methyl methacrylate, and styrene is (20-30):(5-7):1; the mass ratio of toluene, cyclohexanol, and tetrahydrofuran is (2-4):(1-2):1; and the mass ratio of divinylbenzene, azobisisobutyronitrile, and polyvinyl alcohol is (6-7):(1-3):1.
[0009] In step 1, the mixing conditions are as follows: under nitrogen conditions, the stirring speed is 200 rpm, the stirring is first carried out at a stirring temperature of 60-65℃ for 4 hours, and then stirred at a stirring temperature of 70-75℃ for 3 hours. In step 1, the freeze-drying conditions are: freeze-drying temperature -50℃ and freeze-drying time 24-48h. In step 1, the washing conditions are as follows: washing with hot water and cold water in sequence; the extraction conditions are as follows: Soxhlet extraction with ethanol, extraction temperature of 70°C, and extraction reagent method: extraction with acetone / ethanol mixture and hot ethanol in sequence. Step 2, ANMA amylopyridine modification: The ANMA microspheres obtained in Step 1 are added to a hydroxylamine hydrochloride solution and stirred for reaction. After the reaction is complete, the mixture is filtered, washed and vacuum dried to obtain amylopyridine copolymer resin porous microspheres, abbreviated as AOMA. In step 2, the stirring reaction conditions are as follows: stirring temperature is 65-70℃, stirring time is 24 h; and the concentration of hydroxylamine hydrochloride solution is 0.1 g / mL. In step 2, the washing conditions are as follows: washing is performed sequentially with deionized water and ethanol. In step 2, the vacuum drying conditions are: drying temperature of 60℃ and drying time of 24-48 h. Step 3, grafting of polyethyleneimine: First, the AOMA obtained in Step 2 is dispersed in an aqueous solution of ethylenediamine and reacted to obtain amination microspheres. Then, the amination microspheres are immersed in an aqueous solution of glutaraldehyde for oscillation activation to obtain activated amination microspheres. After oscillation activation, the microspheres are rapidly washed with ice water. Finally, the activated amination microspheres are dispersed in an aqueous solution of PEI and reacted with oscillation. After the reaction is completed, the product is filtered, washed, and freeze-dried to obtain porous microspheres of polyethyleneimine grafted modified amine oxime copolymer resin, abbreviated as AOMA-PEI. In step 3, the hydrothermal reaction conditions are as follows: hydrothermal reaction temperature is 80-85℃, hydrothermal reaction time is 12h; and the concentration of the ethylenediamine aqueous solution is 50 wt%. In step 3, the conditions for oscillation activation are: oscillation activation temperature of 40-45℃, oscillation activation time of 2 h; and the concentration of glutaraldehyde aqueous solution is 2.5 wt%. In step 3, the conditions for the oscillation reaction are: oscillation reaction temperature of 40-45℃, oscillation reaction time of 6 h; and the concentration of the PEI aqueous solution of 2.0 wt%. In step 3, the freeze-drying conditions are: freeze-drying temperature of -50℃ and freeze-drying time of 24-48h.
[0010] When grafted modified amine oxime copolymer resin porous microspheres are used as column adsorption materials in molybdenum technetium generators, the adsorption capacity remains at 350-440 mg / g under irradiation conditions with an absorbed dose of 50-500 kGy.
[0011] The technical effects of this invention have been tested experimentally, and the specific results are as follows: FTIR and XPS tests revealed that AOMA-PEI exhibits characteristic peaks for C=N and NO, indicating the achievement of amylopyridine oxime. Furthermore, it also exhibits characteristic peaks for aliphatic -NH2 / -NH, indicating the achievement of PEI grafting.
[0012] SEM testing revealed that AOMA-PEI maintains a micron-sized spherical structure with a diameter of 200 mm and a dense microporous structure on its surface.
[0013] According to BET testing, the specific surface area of AOMA-PEI is 93-99 m². 2 / g, characterized by a high proportion of mesopores, with mesopore volumes ranging from 0.30 to 0.40 cm³. 3 / g.
[0014] Compression performance tests show that AOMA-PEI has a strength of 31-35 MPa and a tensile stress of 55-60 MPa, which proves that AOMA-PEI has good compression performance and network structure stability.
[0015] Irradiation stability tests show that AOMA-PEI has an adsorption capacity of 350-440 mg / g under absorbed dose conditions of 50-500 kGy, and AOMA-PEI exhibits radiation resistance stability.
[0016] Therefore, the AOMA-PEI resin of the present invention has the following advantages: 1. High-capacity adsorption of Mo(VI) ions is achieved through the synergistic effect of the amylopyrime group and the amino / imino group of PEI, and it has radiation stability. 2. AOMA-PEI resin with good mechanical stability can be obtained, that is, the adsorption capacity is improved while the mechanical stability is improved; 3. AOMA-PEI resin with abundant mesoporous structure and uniform pore size distribution can be obtained, providing a channel for the rapid diffusion of Mo(VI) ions and improving adsorption performance. Attached Figure Description
[0017] Figure 1 The FTIR plots of ANMA, AOMA, and AOMA-PEI in Example 1 and Comparative Example 1 are shown. Figure 2 XPS plots of ANMA, AOMA, and AOMA-PEI in Example 1 and Comparative Example 1; Figure 3 This is a SEM image of the ANMA surface in Example 1; Figure 4 This is a SEM image of the AOMA surface in Example 1; Figure 5This is a SEM image of the AOMA-PEI surface in Example 1; Figure 6 The nitrogen adsorption-desorption isotherms for ANMA, AOMA, and AOMA-PEI in Example 1 are shown. Figure 7 The pore size distribution curves of ANMA, AOMA, and AOMA-PEI in Example 1 are shown. Figure 8 The compression performance of ANMA, AOMA, and AOMA-PEI in Example 1 was tested. Detailed Implementation
[0018] The present invention will be further described in detail through embodiments and with reference to the accompanying drawings, but this is not intended to limit the scope of the invention. Example
[0019] A method for preparing porous microspheres of graft-modified amine oxime copolymer resin includes the following steps: Step 1, Synthesis of ANMA Microspheres: First, acrylonitrile, methyl methacrylate, and styrene were used as raw materials; toluene, cyclohexanol, and tetrahydrofuran were used as porogens; divinylbenzene was used as a crosslinking agent; azobisisobutyronitrile (AIBN) was used as an initiator; and polyvinyl alcohol was used as an aqueous dispersant. 24 g of acrylonitrile, 6.0 g of methyl methacrylate, 1 g of styrene, 2.1 g of divinylbenzene, 0.3 g of AIBN, 40 g of toluene, 20 g of cyclohexanol, and 20 g of tetrahydrofuran were mixed to obtain an oil phase. Simultaneously, 1.0 g of polyvinyl alcohol and 200 mL of water were mixed to obtain an aqueous phase. Then, under nitrogen atmosphere and with a stirring speed of 200 rpm, the oil and aqueous phases were mixed and stirred. After stirring, the porogens were washed and extracted to remove them. Finally, after displacement, the mixture was freeze-dried under vacuum at -50°C for 24 h to obtain acrylonitrile / methyl methacrylate copolymer resin porous microspheres, abbreviated as ANMA. In step 1, the mixing conditions are as follows: first, stir at a stirring temperature of 65°C for 4 hours, and then stir at a stirring temperature of 75°C for 3 hours. In step 1, the washing conditions are as follows: washing with hot water and cold water in sequence; the extraction conditions are as follows: Soxhlet extraction with ethanol, extraction temperature of 70°C, and extraction reagent method: extraction with acetone / ethanol mixture and hot ethanol in sequence. To verify the composition of the ANMA resin, FTIR testing was performed. The test results are as follows. Figure 1 As shown, ANMA exhibits a characteristic peak of -C≡N.
[0020] To further confirm the composition of ANMA, XPS testing was performed. The test results are as follows: Figure 2 As shown, ANMA exhibits a characteristic peak of -C≡N.
[0021] Both FTIR and XPS tests show that ANMA exhibits a characteristic peak of -C≡N.
[0022] To demonstrate the microstructure of ANMA, SEM measurements were performed on the surface. The test results are as follows: Figure 3 As shown, ANMA is a micron-sized spherical structure with a diameter of 200 mm. Further magnification reveals that the surface of ANMA consists of interconnected micropores.
[0023] To further demonstrate the pore structure characteristics of ANMA, BET tests were conducted. The test results show that the specific surface area of ANMA is 25.47 m². 2 / g; where The results of the nitrogen adsorption-desorption isotherm test are as follows: Figure 6 As shown, ANMA exhibits a low proportion of mesopores; calculations indicate that the mesopore volume is 0.09 cm³. 3 / g; The pore size distribution test results are as follows Figure 7 As shown, ANMA exhibits a narrow pore size distribution peak, indicating that the internal pore size of ANMA is uniform.
[0024] To demonstrate the compression performance of ANMA, compression performance tests were conducted. The test results are as follows: Figure 8 As shown, the strength of ANMA is 2.51 MPa and the tensile stress is 28.45 MPa.
[0025] Step 2, ANMA amylopyridine modification: Under the conditions of stirring temperature of 70℃ and stirring time of 24 h, the ANMA microspheres obtained in Step 1 were added to a 0.1 g / mL hydroxylamine hydrochloride solution for stirring reaction. After the reaction was completed, the microspheres were filtered, washed and vacuum dried to obtain amylopyridine copolymer resin porous microspheres, abbreviated as AOMA. In step 2, the washing conditions are as follows: washing is performed sequentially with deionized water and ethanol. In step 2, the vacuum drying conditions are: drying temperature of 60℃ and drying time of 24 h. To verify the composition of the AOMA resin, FTIR testing was performed. The test results are as follows. Figure 1 As shown, AOMA exhibits characteristic peaks for C=N and NO, while the characteristic peak for -C≡N disappears. The test results indicate that the cyano group was successfully converted to a amidoxime group through the amidoxime modification in step 2.
[0026] To further confirm the presence of AOMA, XPS testing was performed. The test results are as follows: Figure 2As shown, AOMA exhibits characteristic peaks of -CONH2 and -C=N-OH, which are associated with the amygdoxime group. Both FTIR and XPS results confirm successful amygdoxime modification.
[0027] To verify the microstructure of AOMA, SEM testing was performed. The surface SEM test results are as follows: Figure 4 As shown, AOMA also maintains a micron-sized spherical structure with a diameter of 200 mm. Further magnification reveals that there is a porous network on the surface of AOMA.
[0028] To further demonstrate the pore structure characteristics of AOMA, BET testing was conducted. The test results show that the specific surface area of AOMA is 92.41 m². 2 / g. Test results showed that oximeylation significantly increased the specific surface area, with an increase of up to 262.8%; among which, The nitrogen adsorption-desorption isotherm test results are as follows: Figure 6 As shown, ANMA exhibits a high proportion of mesopores; calculations indicate that the mesopore volume is 0.32 cm³. 3 / g. Test results show that amine oxime saturation can significantly increase mesopore volume data, with an increase of up to 255.6%; The pore size distribution test results are as follows Figure 7 As shown, AOMA exhibits a wide pore size distribution peak, indicating that AOMA possesses a rich hierarchical porous structure.
[0029] To demonstrate the compressibility of AOMA, a compressibility test was conducted. The test results are as follows: Figure 8 As shown, AOMA has a strength of 28.64 MPa and a tensile stress of 17.98 MPa. The test results indicate that although oxime amineization can significantly improve the strength of the resin by as much as 1041.0%, it leads to a significant decrease in tensile stress, which is only 63.2% of that of ANMA.
[0030] To demonstrate the adsorption performance of AOMA, Mo(VI) adsorption performance was tested. The test results are shown in Table 1, and the adsorption capacity of AOMA is 396 mg / g.
[0031] Step 3, grafting of polyethyleneimine: First, the AOMA obtained in Step 2 was dispersed in a 50 wt% ethylenediamine aqueous solution and subjected to a hydrothermal reaction at a temperature of 80℃ for 12 h to obtain amination microspheres. Then, the amination microspheres were immersed in a 2.5 wt% glutaraldehyde aqueous solution for oscillation activation at a temperature of 40℃ for 2 h to obtain activated amination microspheres. After oscillation activation, the microspheres were rapidly washed with ice water. Finally, the activated amination microspheres were dispersed in a 2.0 wt% PEI aqueous solution for oscillation reaction at a temperature of 40℃ for 6 h. After the reaction, the product was filtered, washed, and freeze-dried to obtain porous microspheres of polyethyleneimine grafted modified amine oxime copolymer resin, abbreviated as AOMA-PEI. The freeze-drying conditions are as follows: freeze-drying temperature is -50℃ and freeze-drying time is 48 h.
[0032] To verify the composition of the AOMA-PEI resin, FTIR testing was performed. The test results are as follows: Figure 1 As shown, AOMA-PEI exhibits characteristic peaks of both amylopectin and aliphatic amine CN groups. The test results indicate that the PEI chain was successfully grafted onto the AOMA backbone.
[0033] To further confirm the composition of AOMA-PEI, XPS testing was performed. The test results are as follows: Figure 2 As shown, AOMA-PEI exhibits characteristic peaks for C=N and NO, as well as characteristic peaks for -NH2 / -NH. Both FTIR and XPS tests demonstrate that the PEI chain has been successfully grafted onto the AOMA main chain.
[0034] To verify the microstructure of AOMA-PEI, SEM testing was performed. The test results are as follows: Figure 5 As shown, AOMA-PEI also maintains a micron-sized spherical structure with a diameter of 200 mm. Further magnification reveals that the surface of AOMA-PEI has an even denser microporous structure.
[0035] To further demonstrate the pore structure characteristics of AOMA-PEI, BET testing was conducted. The test results show that the specific surface area of AOMA-PEI is 93.02 m². 2 / g. Test results show that the effect of PEI grafting on the specific surface area is negligible, meaning it does not disrupt the original porous structure of AOMA; among which, The results of the nitrogen adsorption-desorption isotherm test are as follows: Figure 6 As shown, AOMA-PEI also exhibits a high proportion of mesopores; calculations show that the mesopore volume is 0.35 cm³. 3 / g. Test results show that PEI grafting can further improve the mesopore volume data, with an increase of 9.4%; The pore size distribution test results are as follows Figure 7 As shown, AOMA-PEI exhibits a wide pore size distribution peak, indicating that the grafted PEI retains the characteristics of a mesoporous structure and there is no pore collapse.
[0036] To demonstrate the compressibility of AOMA-PEI, compression performance tests were conducted. The test results are as follows: Figure 8 As shown, the strength of AOMA-PEI is 32.38 MPa, and the tensile stress is 58.41 MPa. Test results indicate that PEI grafting not only significantly improves the resin's strength by 13.1%, but also significantly increases the tensile stress, exceeding AOMA's by 224.9% and even surpassing ANMA's by 105.3%. These compression performance test results demonstrate that PEI grafting significantly improves the network structure stability of the resin.
[0037] To demonstrate the adsorption performance of AOMA-PEI, specifically its application as a column adsorption material in a molybdenum-technetium generator, Mo(VI) adsorption performance was tested. The test results are shown in Table 1. The adsorption capacity of AOMA-PEI was 447 mg / g. Compared with the AOMA obtained in step 2, grafting PEI significantly improved the Mo(VI) adsorption capacity, with an increase of 12.8%.
[0038] Table 1. Comparison of adsorption capacities of AOMA and AOMA-PEI
[0039] To further demonstrate the radiation resistance of AOMA-PEI, specifically its application as a column adsorbent in molybdenum-technetium generators, radiation stability tests were conducted. The test results are shown in Table 2. Under absorbed dose conditions of 50-500 kGy, the adsorption capacity of AOMA-PEI was 350-440 mg / g. These results indicate that AOMA-PEI possesses radiation resistance.
[0040] Table 2 Radiation resistance test at different absorbed doses
[0041] To demonstrate the effect of PEI addition on resin adsorption performance, Comparative Examples 1, 2, 3, and 4 are provided, with preparation methods using PEI grafting amounts of 0.5 wt%, 1.0 wt%, 3.0 wt%, and 4.0 wt%.
[0042] Comparative Example 1 A method for preparing a resin with PEI addition of 0.5 wt% is provided. The steps not specifically described are the same as in Example 1, except that in step 3, the mass percentage of the PEI aqueous solution is replaced by 0.5 wt% instead of 2.0 wt%. The resulting resin is referred to as AOMA-PEI-0.5 wt%.
[0043] The adsorption performance test results of AOMA-PEI-0.5 wt% are shown in Table 1. The adsorption capacity of AOMA-PEI-0.5 wt% is 392 mg / g.
[0044] Comparative Example 2 A method for preparing a resin with 1.0 wt% PEI is provided. The steps not specifically described are the same as in Example 1, except that in step 3, the mass percentage of the PEI aqueous solution is replaced with 1.0 wt%, and the resulting resin is referred to as AOMA-PEI-1.0 wt%.
[0045] The adsorption performance test results of AOMA-PEI-1.0 wt% are shown in Table 1. The adsorption capacity of AOMA-PEI-1.0 wt% is 401 mg / g.
[0046] Comparative Example 3 A method for preparing a resin with PEI addition of 3.0 wt% is provided. The steps not specifically described are the same as in Example 1, except that in step 3, the mass percentage of the PEI aqueous solution is replaced with 3.0 wt%, and the resulting resin is referred to as AOMA-PEI-3.0 wt%.
[0047] The adsorption performance test results of AOMA-PEI-3.0 wt% are shown in Table 1. The adsorption capacity of AOMA-PEI-1.0 wt% is 419 mg / g.
[0048] Comparative Example 4 A method for preparing a resin with 4.0 wt% PEI is provided. The steps not specifically described are the same as in Example 1, except that in step 3, the mass percentage of the PEI aqueous solution is replaced with 4.0 wt%, and the resulting resin is referred to as AOMA-PEI-4.0 wt%.
[0049] The adsorption performance test results of AOMA-PEI-4.0 wt% are shown in Table 1. The adsorption capacity of AOMA-PEI-4.0 wt% is 396 mg / g.
[0050] As shown in Example 1 and Comparative Examples 1-4, the amount of PEI grafted has a significant impact on the resin's adsorption performance. Specifically, When the amount of PEI grafted is small, the number of adsorption sites is small due to the small amount of PEI introduced, resulting in a low adsorption capacity. When the amount of PEI grafted is too high, the excessive introduction of PEI will cause pore blockage, which will eventually lead to a decrease in adsorption capacity.
Claims
1. A porous microsphere made of graft-modified amine oxime copolymer resin, characterized in that: Acrylonitrile, methyl methacrylate, and styrene were used as comonomers, divinylbenzene was used as a crosslinking agent, and azobisisobutyronitrile was used as an initiator. Copolymer resin microspheres ANMA were formed by suspension polymerization. Then, they were subjected to a hydroxylamine hydrochloride solution for a amine oxime reaction to obtain amine oxime-modified microspheres AOMA. Finally, after ethylenediamine amination, glutaraldehyde activation, and polyethyleneimine (PEI) grafting modification, graft-modified amine oxime-modified copolymer resin porous microspheres AOMA-PEI were obtained. The AOMA-PEI has characteristic functional groups of amine oxime group -C(NH2)=N-OH and aliphatic amine CN.
2. The graft-modified amine oxime copolymerized resin porous microspheres according to claim 1, characterized in that: The micro-morphology of the AOMA-PEI is a microspherical structure; the specific surface area is 93-99 m 2 / g, and the mesopore volume data is 0.30-0.40 cm 3 / g.
3. The graft-modified amine oxime copolymerized resin porous microspheres according to claim 1, characterized in that: The strength of AOMA-PEI is 31-35 MPa, and the tensile stress is 55-60 MPa.
4. A method for preparing porous microspheres of graft-modified amine oxime copolymer resin, characterized in that... Includes the following steps: Step 1, Synthesis of ANMA Microspheres: First, acrylonitrile, methyl methacrylate, and styrene are used as raw materials; toluene, cyclohexanol, and tetrahydrofuran are used as porogens; divinylbenzene is used as a crosslinking agent; azobisisobutyronitrile (AIBN) is used as an initiator; and polyvinyl alcohol is used as an aqueous dispersant. Acrylonitrile, methyl methacrylate, styrene, divinylbenzene, AIBN, toluene, cyclohexanol, and tetrahydrofuran are mixed to obtain an oil phase. Simultaneously, polyvinyl alcohol and water are mixed to obtain an aqueous phase. Then, the oil phase and aqueous phase are mixed and stirred. After stirring, the porogens are removed by washing and extraction. Finally, after displacement, the mixture is freeze-dried under vacuum to obtain acrylonitrile / methyl methacrylate copolymer resin porous microspheres, abbreviated as ANMA. Step 2, ANMA amylopyridine modification: The ANMA microspheres obtained in Step 1 are added to a hydroxylamine hydrochloride solution and stirred for reaction. After the reaction is complete, the mixture is filtered, washed and vacuum dried to obtain amylopyridine copolymer resin porous microspheres, abbreviated as AOMA. Step 3, grafting of polyethyleneimine: First, the AOMA obtained in Step 2 is dispersed in an aqueous solution of ethylenediamine and reacted to obtain amination microspheres. Then, the amination microspheres are immersed in an aqueous solution of glutaraldehyde for oscillation activation to obtain activated amination microspheres. After oscillation activation, the microspheres are rapidly washed with ice water. Finally, the activated amination microspheres are dispersed in an aqueous solution of PEI and reacted with oscillation. After the reaction is completed, the product is filtered, washed, and freeze-dried to obtain porous microspheres of polyethyleneimine grafted modified amine oxime copolymer resin, abbreviated as AOMA-PEI.
5. The preparation method according to claim 4, characterized in that: In step 1, the mass ratio of acrylonitrile, methyl methacrylate, and styrene is (20-30):(5-7):1; the mass ratio of toluene, cyclohexanol, and tetrahydrofuran is (2-4):(1-2):1; and the mass ratio of divinylbenzene, azobisisobutyronitrile, and polyvinyl alcohol is (6-7):(1-3):
1.
6. The preparation method according to claim 4, characterized in that: In step 1, the mixing conditions are as follows: under nitrogen conditions, the stirring speed is 200 rpm, the stirring is first carried out at a stirring temperature of 60-65℃ for 4 hours, and then stirred at a stirring temperature of 70-75℃ for 3 hours. In step 2, the stirring reaction conditions are as follows: stirring temperature is 65-70℃, stirring time is 24 h; and the concentration of hydroxylamine hydrochloride solution is 0.1 g / mL.
7. The preparation method according to claim 4, characterized in that: In step 3, the hydrothermal reaction conditions are as follows: hydrothermal reaction temperature is 80-85℃, hydrothermal reaction time is 12 h; and the concentration of the ethylenediamine aqueous solution is 50 wt%. In step 3, the conditions for oscillation activation are: oscillation activation temperature of 40-45℃, oscillation activation time of 2 h; and the concentration of glutaraldehyde aqueous solution is 2.5 wt%. In step 3, the conditions for the oscillation reaction are: oscillation reaction temperature of 40-45℃, oscillation reaction time of 6 h, and concentration of PEI aqueous solution of 2.0 wt%.
8. The preparation method according to claim 4, characterized in that: In step 1, the freeze-drying conditions are: freeze-drying temperature of -50℃ and freeze-drying time of 24-48 h. In step 1, the washing conditions are as follows: washing with hot water and cold water in sequence; the extraction conditions are as follows: Soxhlet extraction with ethanol, extraction temperature of 70°C, and extraction reagent method: extraction with acetone / ethanol mixture and hot ethanol in sequence. In step 2, the washing conditions are as follows: washing is performed sequentially with deionized water and ethanol. In step 2, the vacuum drying conditions are: drying temperature of 60℃ and drying time of 24-48 h. In step 3, the freeze-drying conditions are: freeze-drying temperature of -50℃ and freeze-drying time of 24-48 h.
9. The graft-modified amine oxime copolymerized resin porous microspheres according to claim 1, characterized in that: When used as a column adsorption material in molybdenum-technetium generators, the adsorption capacity remains at 350-440 mg / g under irradiation conditions with an absorbed dose of 50-500 kGy.