Sulfur-containing organic silicon gel material as well as preparation method and application thereof

Abstract

The invention discloses a sulfur-containing organic silicon gel material and a preparation method and application thereof, and the preparation method comprises the following steps: in the presence of a solvent, a sulfhydryl compound and an epoxy group of an epoxy group-containing silane coupling agent are subjected to a ring-opening reaction, and meanwhile, an alkoxy group of the epoxy group-containing silane coupling agent is subjected to a hydrolytic condensation reaction to obtain the sulfur-containing organic silicon gel material. And freeze-drying to obtain the sulfur-containing organic silicon gel material. The organic silicon material is prepared through hydrolytic condensation of the silane coupling agent, meanwhile, the sulfhydryl-containing compound and an epoxy group of the epoxy group-containing silane coupling agent are subjected to a ring-opening reaction, a large number of sulfur-containing groups are introduced into the organic silicon material in a covalent bond mode, lone pair electrons of sulfur serve as adsorption sites of iodine, and the adsorption capacity of the material to iodine is improved; the silicon substrate ensures that the material has high irradiation resistance and acid resistance, so that efficient adsorption and enrichment of volatile iodine isotopes are realized; the sulfur-containing organosilicon gel material is rapidly prepared through a one-step method, the preparation method is simple, and the cost is low.

Description

Technical Field

[0001] The present invention relates to the technical field of adsorption materials, and particularly relates to a sulfur-containing organosilica gel material, a preparation method thereof, and an application thereof. Background Art

[0002] With the development of nuclear energy and nuclear technology, the proportion of radionuclides in the fields of energy, national defense, medical treatment, and industry is increasing day by day, but this also leads to the generation of a large amount of radioactive waste. Radioactive iodine is the main gaseous pollutant, and it is one of the early warning radionuclides for radioactive leakage in nuclear power plants. Among them 129 I has a half-life of about 1.57×10 7 years and is considered to be one of the main sources of long-term radioactive pollutants. And 131 I is one of the most widely used radioactive isotopes in nuclear medicine, and there is a risk of being released into the environment during its production and use. Due to the volatility, diffusibility, and radioactivity of iodine, leakage may cause large-scale environmental problems. It can also enter the human body through inhalation or accidental ingestion, leading to thyroid cancer or leukemia through internal radiation. Therefore, the monitoring and treatment of radioactive iodine isotopes are of great significance for the sustainable development of the nuclear industry and nuclear medicine and environmental protection. However, dealing with interfering factors in the environment, such as volatile organic compounds and water vapor in the air, are the main challenges for efficient iodine capture.

[0003] Currently, the adsorption materials for radioactive iodine mainly include porous carbon materials impregnated with organic amines, metal-doped materials, polymer microspheres, and porous framework materials. Porous carbon materials impregnated with organic amines and polymer microspheres have low preparation costs, but are seriously affected by humidity and have low adsorption capacities. Metal-doped materials such as silver and bismuth have the advantage of high removal depth, but such materials have high costs, low adsorption capacities, and are seriously affected by water vapor in terms of removal efficiency. Organic porous framework materials, including MOFs, COFs, CMPs, etc., are highly efficient iodine adsorbents developed recently. They have the advantages of adjustable pore structures, excellent radiation resistance, and high adsorption capacities. However, the preparation of this material is complex, the reaction conditions are harsh, and the preparation cost is high.

[0004] In summary, although there are various types of current iodine adsorption materials, generally, they still fail to meet the requirements for iodine purification and enrichment in most specific environments in terms of adsorption capacity and selectivity. For example, in the environment of nuclear industry reprocessing, due to high radiation, acidity of the gas phase, and high humidity, etc., the stability and purification ability of iodine isotopes decline. Although some hydrophobic porous framework materials have significantly improved iodine adsorption performance currently, their complex synthesis processes and expensive raw materials have become important challenges restricting their development. Therefore, it is of great significance to research and develop a sulfur-containing organosilicon material with a simple preparation method, low cost, stability, and high adsorption and enrichment effects on radioactive iodine. Summary of the Invention

[0005] In view of the deficiencies in the prior art, the present invention provides a sulfur-containing organosilicon gel material, a preparation method thereof and an application thereof. Using a thiol compound with low price and an epoxy group-containing silane coupling agent as polymerization units, the silane coupling agent undergoes hydrolysis and condensation reactions to prepare an organosilicon material. At the same time, the epoxy group of the thiol compound and the epoxy group-containing silane coupling agent undergoes a ring-opening reaction, and a large number of sulfur-containing groups are introduced into the organosilicon material in a covalent bond manner. The lone pair electrons of sulfur can serve as adsorption sites for iodine, thereby increasing the iodine adsorption capacity of the material; at the same time, the silicon substrate can ensure that the material has high radiation resistance and acid resistance, so as to achieve efficient adsorption and enrichment of volatile iodine isotopes.

[0006] To solve the above technical problems, the first aspect of the present invention provides a preparation method of a sulfur-containing organosilicon gel material, comprising the following steps:

[0007] In the presence of a solvent, the epoxy group of the thiol compound and the epoxy group-containing silane coupling agent undergoes a ring-opening reaction. At the same time, the alkoxy group of the epoxy group-containing silane coupling agent undergoes hydrolysis and condensation reaction, and after freeze-drying, the sulfur-containing organosilicon gel material is obtained.

[0008] The present invention uses a thiol compound with low price and an epoxy group-containing silane coupling agent as reactants. The silane coupling agent prepares an organosilicon material through hydrolysis and condensation reactions. At the same time, the epoxy group of the thiol compound and the epoxy group-containing silane coupling agent undergoes a ring-opening reaction, and a large number of sulfur-containing groups are introduced into the organosilicon material in a covalent bond manner. The lone pair electrons of sulfur can serve as adsorption sites for iodine, thereby increasing the iodine adsorption capacity of the material; at the same time, the silicon substrate can ensure that the material has high radiation resistance and acid resistance, so as to achieve efficient adsorption and enrichment of volatile iodine isotopes; in addition, the sulfur-containing organosilicon gel material is rapidly prepared by a one-step method, and the preparation method is simple and the cost is low.

[0009] Further, the thiol compound is:

[0010]

[0011] One or more of them.

[0012] Further, the epoxy group-containing silane coupling agent is:

[0013] One or more of them.

[0014] Further, the temperature of the ring-opening reaction and the hydrolysis and condensation reaction is 60-100 °C, and the time is 6-48 h.

[0015] Further, the solvent is water, methanol or ethanol.

[0016] Further, the molar ratio of the epoxy group-containing silane coupling agent to the mercapto compound is 3:1 - 1:2.

[0017] Further, the hydrolysis and condensation reaction is carried out under the action of a catalyst, and the catalyst is an acid solution with a concentration of 0.1 - 1 M or an alkali solution with a concentration of 0.01 - 0.5 M. Among them, the hydrolysis and condensation reaction can also be carried out without a catalyst.

[0018] Further, the alkali solution is a solution of one or more of potassium carbonate, sodium hydroxide, sodium hydroxide, ammonia water, and triethylamine, and the acid solution is a solution of hydrochloric acid and / or sulfuric acid. More preferably, the solution is an aqueous solution.

[0019] The second aspect of the present invention provides a sulfur-containing organosilicon gel material prepared by the preparation method described in the first aspect.

[0020] The third aspect of the present invention provides an application of the sulfur-containing organosilicon gel material described in the second aspect in the adsorption of radionuclides.

[0021] Advantages of the present invention:

[0022] The present invention prepares an organosilicon material through the hydrolysis and condensation of alkoxy groups in a silane coupling agent. At the same time, the mercapto group-containing compound undergoes a ring-opening reaction with the epoxy group of the epoxy group-containing silane coupling agent, introducing a large number of sulfur-containing groups into the organosilicon material in a covalent bond manner. The lone pair electrons of sulfur can serve as adsorption sites for iodine, thereby improving the iodine adsorption capacity of the material.

[0023] The silicon substrate of the present invention can ensure that the material has high radiation resistance and acid resistance to achieve the efficient adsorption and enrichment of volatile iodine isotopes.

[0024] The present invention uses a mercapto group-containing compound and an epoxy group-containing silane coupling agent as polymerization units, with low cost. The sulfur-containing organosilicon gel material is rapidly prepared by a one-step method, and the preparation method is simple. Description of the drawings

[0025] In order to more clearly illustrate the technical solutions of the present invention, the drawings required for use in the examples will be briefly introduced below. Obviously, the drawings in the following description are only examples of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0026] Figure 1 It is the FTIR spectra of the products NSF-PTE-1, NSF-PTE-2, and NSF-PTE-3 in Example 1 of the present invention;

[0027] Figure 2Among them, A - C are the EDS spectra of NSF - PTE - 1, NSF - PTE - 2, and NSF - PTE - 3 of Example 1 of the present invention, respectively, and D - F are the SEM maps of NSF - PTE - 1, NSF - PTE - 2, and NSF - PTE - 3 of Example 1 of the present invention, respectively;

[0028] Figure 3 are the iodine adsorption curves of the products NSF - PTE - 1, NSF - PTE - 2, and NSF - PTE - 3 of Example 1 of the present invention;

[0029] Figure 4 is the adsorption selectivity comparison diagram of the product NSF - PTE of Example 1 of the present invention for iodine vapor;

[0030] Figure 5 are the FTIR spectra of the products NSF - ATPE - 1 and NSF - ATPE - 2 of Example 2 of the present invention;

[0031] Figure 6 Among them, A and B are the EDS maps of the products NSF - ATPE - 1 and NSF - ATPE - 2 of Example 2, respectively, and C and D are the SEM maps of the products NSF - ATPE - 1 and NSF - ATPE - 2 of Example 2, respectively;

[0032] Figure 7 are the iodine adsorption curves of the products NSF - ATPE - 1 and NSF - ATPE - 2 of Example 2 of the present invention;

[0033] Figure 8 is the adsorption selectivity comparison diagram of the product NSF - ATPE of Example 2 of the present invention for iodine vapor. Detailed implementation manners

[0034] The technical solution of the present invention will be clearly and completely described below in conjunction with specific embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without making creative efforts belong to the scope of protection of the present invention.

[0035] Example 1

[0036] This example relates to a preparation method of a sulfur - containing organosilicon gel material, which includes the following steps:

[0037] Dissolve 1 mmol of 1,3-propanedithiol (PT) in 1 mL of H2O, and dropwise add different amounts of 2-(3,4-epoxycyclohexyl)ethyltriethoxysilane (ECES). Stir and react at 60 °C for 6 h, and the solution gradually gels. Wash the obtained gel with deionized water and freeze-dry the washed gel to obtain a white gel material NSF-PTE. Among them, when the molar ratios of PT:ECES are 1:2, 1:1, and 2:1 respectively, the products are labeled NSF-PTE-1, NSF-PTE-2, and NSF-PTE-3. The reaction formula of this example is:

[0038]

[0039] , where 1,3-propanedithiol undergoes a ring-opening reaction with the epoxy group of 2-(3,4-epoxycyclohexyl)ethyltriethoxysilane through the thiol group.

[0040] Test Example 1-1

[0041] Perform infrared characterization analysis on the products NSF-PTE-1, NSF-PTE-2, and NSF-PTE-3 prepared in Example 1. The results are as Figure 1 shown. From the infrared spectrum of NSF-PTE, an absorption peak centered at 3379 cm -1 can be observed, which belongs to the stretching vibration of the silanol O–H formed by the hydrolysis of the siloxane. Absorption peaks at 2861 cm -1 and 2920 cm -1 are attributed to the symmetric and antisymmetric stretching vibrations of methylene (-CH2-), and the vibration absorption peaks of Si-O-C and Si-O-Si are located at 1020 cm -1 and 1096 cm -1 respectively. The absorption peak at 693 cm -1 is attributed to the C-S stretching vibration. The FTIR results confirm the successful synthesis of NSF-PTE.

[0042] Test Example 1-2

[0043] Perform EDS analysis on the products NSF-PTE-1, NSF-PTE-2, and NSF-PTE-3 prepared in Example 1. The results are as Figure 2 shown in A-C. It can be seen that as the molar ratio of PT increases, the sulfur content in the material gradually increases. Perform scanning electron microscope (SEM) analysis on the products NSF-PTE-1, NSF-PTE-2, and NSF-PTE-3 prepared in the example. The results are as Figure 2 shown in D-F. It can be seen that the morphologies of NSF-PTE-1, NSF-PTE-2, and NSF-PTE-3 are all micron-sized spheres, and the particle size of the spheres increases with the increase of the PE feeding ratio.

[0044] Test Examples 1 - 3

[0045] Under ambient pressure, a certain amount of the product NSF - PTE of Example 1 was placed in a sealed container and exposed to iodine vapor at 75 °C. The mass ratio of iodine to NSF - PTE was 50:1, and its iodine adsorption capacity was measured by gravimetry at a predetermined time. As Figure 3 shown, for NSF - PTE - 1, NSF - PTE - 2, and NSF - PTE - 3, the iodine adsorption capacity increased rapidly in the first 2 hours and then increased slowly, reaching the adsorption equilibrium at about 12 hours. The iodine adsorption capacities of NSF - PTE - 1, NSF - PTE - 2, and NSF - PTE - 3 were 1.34 g / g, 1.17 g / g, and 1.44 g / g, respectively.

[0046] In different atmospheres, a certain amount of the product NSF - PTE - 3 of Example 1 was placed in a sealed container and exposed to iodine vapor at 75 °C to investigate the selectivity of the material for iodine vapor, including air containing saturated water vapor, n - hexane, or 5% HNO₃. As Figure 4 shown, where q e,i is the adsorption capacity of NSF - PTE - 3 in the presence of water, n - hexane, or nitric acid, and q e,0 is the adsorption capacity of NSF - PTE - 3 in air. It can be seen that saturated water vapor has basically no effect on the iodine vapor adsorption ability of NSF - PTE, and the organic gas n - hexane and the acidic gas 5% HNO₃ have a slight effect, but the iodine adsorption ability of the material can still maintain 85.6% and 83.3% of the original iodine adsorption capacity, respectively.

[0047] Example 2

[0048] 5 mmol of 4 - aminothiophenol (ATP) was dissolved in 10 mL of ethanol. Then different amounts of ECES were added and stirred at 75 °C for 6 h, and the solution gradually gelated. The obtained gel was washed with deionized water and the washed gel was freeze - dried to obtain a white gel material NSF - ATPE. Among them, when the molar ratios of ATP:ECES were 1:2, 1:1, and 2:1, the products were labeled NSF - ATPE - 1, NSF - ATPE - 2, and NSF - ATPE - 3, respectively. NSF - ATPE - 1 and NSF - ATPE - 2 were used for characterization and adsorption experiments subsequently. The reaction formula for this example is:

[0049]

[0050] , where 4 - aminothiophenol and 2 - (3,4 - epoxycyclohexyl)ethyltriethoxysilane react through the amino and mercapto groups of 4 - aminothiophenol and the epoxy group in 2 - (3,4 - epoxycyclohexyl)ethyltriethoxysilane.

[0051] Test Example 2-1

[0052] The products NSF-ATPE-1 and NSF-ATPE-2 of Example 2 were subjected to infrared spectroscopy analysis, and the results are as Figure 5 shown. An absorption peak centered at 3352 cm -1 was observed, which was attributed to the stretching vibrations of silanol groups, S-H, N-H, and NH2 formed by the hydrolysis of siloxane. Absorption peaks at 2868 cm -1 and 2911 cm -1 were attributed to the symmetric and asymmetric stretching vibrations of methylene (-CH2-), and absorption peaks at 1951 cm -1 and 1493 cm -1 were benzene ring skeleton vibration peaks. A bending vibration peak of NH was found at 1621 cm -1 , and the absorption peak of the skeleton stretching vibration of organosilicon was located at 1150 cm -1 . The absorption peak at 689 cm -1 was attributed to the C-S stretching vibration. The FTIR results confirmed the successful synthesis of NSF-ATPE.

[0053] Test Example 2-2

[0054] The products NSF-ATPE-1 and NSF-ATPE-2 of Example 2 were subjected to EDS analysis. By analyzing the composition of the material through EDS and referring to Figure 6 A and B therein, the results showed that as the feeding ratio of ATP increased, the sulfur content and nitrogen content of the material gradually increased. The products NSF-ATPE-1 and NSF-ATPE-2 of Example 2 were subjected to SEM analysis, and the results are as Figure 6 shown in C and D therein. It can be seen that the morphologies of NSF-ATPE-1 and NSF-ATPE-2 were cheese-like solids.

[0055] Test Example 2-3

[0056] Under ambient pressure, a certain amount of NSF-ATPE of Example 2 was placed in a sealed container and exposed to iodine vapor at 75 °C. The mass ratio of iodine to NSF-ATPE was 50:1, and its iodine adsorption capacity was measured by gravimetry at a predetermined time. As Figure 7 shown, it can be seen that the iodine adsorption capacities of NSF-ATPE-1 and NSF-ATPE-2 were measured to be 2.2 g / g and 2.6 g / g respectively.

[0057] In different atmospheres, a certain amount of NSF-ATPE-2 was placed in a sealed container and exposed to iodine vapor at 75 °C, and the selectivity of the material to iodine vapor was investigated, including air containing saturated water vapor, n-hexane, and 5% HNO3. As Figure 8As shown, saturated water vapor and n-hexane organic gas have basically no effect on the iodine vapor adsorption capacity of NSF-ATPE, and the iodine adsorption capacities of the materials maintain 96.6% and 97.5% of the original adsorption capacity, respectively. 5% nitric acid has a slight effect on iodine adsorption, but the adsorption capacity can still maintain 90.6% of the original adsorption capacity.

[0058] In summary, in the present invention, an organosilicon material is prepared by hydrolysis and condensation of alkoxy groups in a silane coupling agent. At the same time, a ring-opening reaction occurs between the mercapto group-containing compound and the epoxy group of the epoxy group-containing silane coupling agent, and a large number of sulfur-containing groups are introduced into the organosilicon material in a covalent bond manner. The lone pair electrons of sulfur can serve as adsorption sites for iodine, thereby increasing the iodine adsorption capacity of the material; the silicon substrate of the present invention can ensure that the material has high radiation resistance and acid resistance to achieve efficient adsorption and enrichment of volatile iodine isotopes; using a mercapto group-containing compound and an epoxy group-containing silane coupling agent as polymerization units, the cost is low, and the sulfur-containing organosilicon gel material is rapidly prepared by a one-step method, and the preparation method is simple.

[0059] The present invention has been described in detail above in combination with specific embodiments and exemplary examples, but these descriptions should not be construed as limiting the present invention. Those skilled in the art understand that without departing from the spirit and scope of the present invention, various equivalent substitutions, modifications or improvements can be made to the technical solutions and implementation manners of the present invention, and these all fall within the scope of the present invention. The protection scope of the present invention shall be subject to the appended claims.

Claims

1. A preparation method of a sulfur-containing organosilicon gel material, characterized in that It includes the following steps: In the presence of a solvent, the thiol compound undergoes a ring-opening reaction with the epoxy group of the epoxy group-containing silane coupling agent. At the same time, the alkoxy group of the epoxy group-containing silane coupling agent undergoes hydrolysis and condensation reaction. After freeze-drying, the sulfur-containing organosilica gel material is obtained.

2. The preparation method of the sulfur-containing organosilicon gel material according to claim 1, wherein, The thiol compound is: One or more of them.

3. The preparation method of the sulfur-containing organosilicon gel material according to claim 1, characterized in that, The epoxy group-containing silane coupling agent is: One or more of them.

4. The preparation method of the sulfur-containing organosilicon gel material according to claim 1, characterized in that, The temperature of the ring-opening reaction and the hydrolysis and condensation reaction is 60 - 100 °C, and the time is 6 - 48 h.

5. The preparation method of the sulfur-containing organosilicon gel material according to claim 1, characterized in that, The solvent is water, methanol or ethanol.

6. The preparation method of the sulfur-containing organosilicon gel material according to claim 1, characterized in that, The molar ratio of the epoxy group-containing silane coupling agent to the thiol compound is 3:1 - 1:

2.

7. The preparation method of the sulfur-containing organosilicon gel material according to claim 1, characterized in that The hydrolysis and condensation reaction is carried out under the action of a catalyst, and the catalyst is an acid solution with a concentration of 0.1 - 1 M or a base solution with a concentration of 0.01 - 0.5 M.

8. The preparation method of the sulfur-containing organosilicon gel material according to claim 7, wherein, The base solution is a solution of one or more of potassium carbonate, sodium hydroxide, sodium hydroxide, ammonia water, and triethylamine, and the acid solution is a solution of hydrochloric acid and / or sulfuric acid.

9. A sulfur-containing organosilica gel material obtained by the preparation method according to any one of claims 1 - 8.

10. An application of the sulfur-containing organosilica gel material according to claim 9 in the adsorption of radionuclides.

Images