Tritium removal catalyst and preparation method thereof

Abstract

The invention discloses a tritium removal catalyst and a preparation method thereof, and the method comprises the following steps: S1, adding chloroplatinic acid and soluble starch into deionized water to obtain a mixed dispersion liquid; s2, adding a composite surfactant into the mixed dispersion liquid to form mixed sol; s3, carrying out drying treatment on the mixed sol to obtain dried gel; s4, carrying out heat treatment on the dried gel, and then cooling to room temperature to obtain Pt nanogel; s5, hexafluoroisopropanol is added into a reaction kettle, then Pt nanogel, the modified silk fibroin powder and tetraethoxysilane are added, and a complex is obtained; and S6, carrying out preheating treatment on the complex, then carrying out carbonization treatment, and cooling to room temperature to obtain the tritium removal catalyst. The tritium removal catalyst disclosed by the invention has relatively high specific surface area and hydrophobic property, so that the tritium removal catalyst has more active sites, product water molecules are prevented from covering the active sites, tritium gas can be efficiently converted into tritium water which is easy to capture, and deep purification of tritium is realized.

Description

Technical Field

[0001] The present invention belongs to the technical field of nuclear industry, and particularly relates to a tritium removal catalyst and a preparation method thereof. Background Art

[0002] In the field of nuclear energy, the reprocessing of spent fuel is a crucial link, which involves the scientific, safe and effective treatment of the spent fuel discharged from nuclear reactors and the realization of the recycling of nuclear fuel and nuclear resources. Spent fuel is the fuel discharged from the reactor after undergoing nuclear reactions by neutron bombardment, which contains a large amount of unused fissile and fertile materials, as well as transuranic elements generated during the irradiation of nuclear fuel.

[0003] Tritium is continuously produced by natural processes and exists naturally on the earth's surface. A small amount of tritium is produced by the spontaneous fission of uranium and thorium. Tritium can also be formed in nuclear reactor fuels. Whether it is a light water reactor or a liquid metal breeder reactor, it can be formed by ternary fission or by neutron bombardment of light elements such as boron or lithium. The half-life of tritium is 12.33 years, and it forms helium by emitting a low-energy electron (maximum energy of 18 keV, average energy of 5.88 keV). Since the electron energy is low, the external dose to humans is insignificant. In light water reactor fuels, the tritium content in spent fuel increases with burnup. 50% of the tritium present in the fuel is retained in the zirconium alloy cladding, and the remaining 50% is oxidized and dissolved in the dissolver solution in the form of water (HTO). Before the dissolution of spent fuel, tritium should be removed from the spent fuel to simplify the dissolution operation and reduce the volume of high-boiling water in the reprocessing plant. However, due to its radioactivity and difficulty in natural degradation, the treatment and removal of tritium have become an important task to ensure environmental safety and human health. In this context, tritium removal catalysts have emerged.

[0004] However, the current tritium removal catalysts have at least the following deficiencies. For example, Patent CN104485146A discloses a high-efficiency tritium removal purification device and a tritium removal method thereof, and the catalyst used is Pt / Al 2 O 3 , although the dispersion of Pt is good, it does not have hydrophobicity, which will lead to a low service life and cannot be applied to tritium removal in the front-end process of reprocessing; Patent CN104383917A discloses a preparation method of a catalyst for tritium removal from tritium-containing air, and this method synthesizes a Pt / Al 2 O 3 catalyst. Since this catalyst does not have a hydrophobic function, it is easy to cause catalyst poisoning due to water vapor occupying the adsorption sites and cannot be applied to tritium removal in the front-end process of reprocessing. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a tritium removal catalyst and a preparation method thereof in view of the above deficiencies existing in the prior art. The tritium removal catalyst prepared by the present invention has a high specific surface area and hydrophobic properties, enabling it to have more active sites and avoiding the coverage of active sites by product water molecules. It can efficiently convert tritium gas into tritiated water that is easy to capture, realizing the deep purification of tritium.

[0006] The technical solution of the present invention to solve the above technical problems is as follows:

[0007] According to one aspect of the present invention, there is provided a preparation method of a tritium removal catalyst, comprising:

[0008] S1, adding chloroplatinic acid and soluble starch to deionized water, adjusting to a first temperature, and keeping warm and stirring to obtain a mixed dispersion;

[0009] S2, adding a composite surfactant to the mixed dispersion, adjusting the temperature to a second temperature, and keeping warm and stirring to form a mixed sol;

[0010] S3, performing a drying treatment on the mixed sol to obtain a dried gel;

[0011] S4, under the protection of an inert atmosphere, first performing a heat treatment on the dried gel, and then cooling it to room temperature to obtain a Pt nanogel;

[0012] S5, adding hexafluoroisopropanol into a reaction kettle, then adding the Pt nanogel, modified silk fibroin powder, and tetraethyl orthosilicate, adjusting the temperature to a third temperature, keeping warm and stirring, and then placing it in a drying oven for a drying treatment to obtain a composite;

[0013] S6, first performing a preheating treatment on the composite, and then performing a carbonization treatment. After cooling to room temperature, a tritium removal catalyst is obtained.

[0014] Optionally, the mass ratio of the chloroplatinic acid to the soluble starch is 1:12 - 14.

[0015] Optionally, the ratio of the soluble starch to the deionized water is 14 - 18 g:120 mL.

[0016] Optionally, the first temperature is 80 - 90 °C.

[0017] Optionally, the soluble starch is prepared by the following steps:

[0018] S101, adding starch and an ethanol solution to a reactor in sequence, adjusting the temperature to a fourth temperature, and then stirring to obtain a mixed solution;

[0019] S102. Then, add sodium hydroxide solution into the reaction kettle, adjust the pH to 11 - 11.5, adjust the temperature to the fifth temperature, keep warm, stir and react for a period of time, then add maleic anhydride, continue stirring, and then add hydrochloric acid solution to adjust the pH of the system in the reaction kettle to neutral. Finally, obtain the soluble starch through rotary evaporation and drying.

[0020] Optionally, the starch is any one of corn starch and soybean starch.

[0021] Optionally, the ratio of the starch to the ethanol solution is 8 - 12 g: 100 mL.

[0022] Optionally, the fifth temperature is 55 - 60 °C.

[0023] Optionally, the addition amount of maleic anhydride is 4 - 5% of the total mass of the starch.

[0024] Optionally, the mass ratio of the mixed dispersion liquid to the composite surfactant is 20: 1 - 1.5.

[0025] Optionally, the composite surfactant is prepared by the following steps:

[0026] S201. Add 1 - methylimidazole into the reaction kettle, discharge the air in the reaction kettle, then adjust the temperature to the sixth temperature, keep warm, and then dropwise add dodecyl chloride, continue to keep warm, and stir and react for a period of time to obtain an intermediate mixture;

[0027] S202. Recrystallize the intermediate mixture in ethyl acetate, and then, after filtration and vacuum drying, obtain the first reactant;

[0028] S203. Mix the first reactant with sodium hydroxyethyl sulfonate to obtain the composite surfactant.

[0029] Optionally, the molar ratio of 1 - methylimidazole to dodecyl chloride is 10 - 12: 9.

[0030] Optionally, the second temperature is 75 - 78 °C, and the heat preservation and stirring time in step S2 is 1 - 1.5 h.

[0031] Optionally, the dried gel is first subjected to heat treatment, specifically: treat at 510 - 520 °C for 2 - 3 h.

[0032] Optionally, the mixing mass ratio of hexafluoroisopropanol, the Pt nanogel, the modified silk fibroin powder, and tetraethyl orthosilicate is 20 - 25: 12 - 14: 4 - 6: 1 - 1.2.

[0033] Optionally, the modified silk fibroin powder is prepared by the following steps:

[0034] S501, Add the silkworm cocoons to the mixed solution of sodium carbonate and sodium alginate, adjust the temperature to the seventh temperature, keep warm, stir, filter, and wash with water until neutral to obtain pretreated silkworm cocoons;

[0035] S502, Crush the pretreated silkworm cocoons to obtain crushed pretreated silkworm cocoons;

[0036] S503, Add the crushed pretreated silkworm cocoons to the lithium bromide solution, adjust the temperature to the eighth temperature, keep warm, stir, and then perform dialysis treatment to obtain dialysis material;

[0037] S504, Perform vacuum drying on the dialysis material to obtain the modified silk fibroin protein powder.

[0038] Optionally, the mass ratio of the silkworm cocoons to the mixed solution of sodium carbonate and sodium alginate is 1:10 - 12.

[0039] Optionally, the mass ratio of the lithium bromide solution to the crushed pretreated silkworm cocoons is 1:10 - 12.

[0040] Optionally, the dialysis treatment uses a dialysis bag with a specification of 50 kDa to remove impurities smaller than 50 kDa.

[0041] Optionally, the third temperature is 40 - 45 °C.

[0042] Optionally, the complex is preheated first, specifically: in an air atmosphere, the complex is first heated at a rate of 4 - 5 °C / min to 400 - 420 °C, and then kept warm for 30 - 40 min.

[0043] Optionally, the carbonization treatment is specifically: under the protection of a nitrogen atmosphere, the preheated complex is heated at a heating rate of 1.5 - 2 °C / min to 610 - 615 °C and kept warm for 2 h - 2.5.

[0044] According to another aspect of the present invention, a tritium removal catalyst is provided, which is prepared by the method described above. The surface of the catalyst particles is rough, and it has a microscopic pore structure inside, and the water contact angle reaches more than 155.5°.

[0045] The tritium removal catalyst of the present invention and its preparation method have the following beneficial effects compared with the prior art:

[0046] (1) The tritium removal catalyst prepared by the present invention not only has high catalytic performance and stable chemical properties, providing a strong basis for the removal of tritium gas. At the same time, it also has a high specific surface area and hydrophobic properties, enabling it to have more active sites and avoid the coverage of active sites by product water molecules. The utilization rate of active sites is high, and it can efficiently convert tritium gas into tritiated water that is easy to capture, realizing the deep purification of tritium in the front-end process of spent fuel reprocessing.

[0047] (2) During the catalytic purification process of tritium gas, the tritium removal catalyst prepared by the present invention mainly improves the catalytic conversion rate of tritium gas by providing active sites and reducing the reaction activation energy. At a certain temperature, the highest catalytic conversion rate can reach nearly 100%. At the same time, due to the relatively complex structure of the tritium removal catalyst prepared by the present invention, it has high selectivity and stability, and can maintain the high-efficiency removal ability of tritium gas in a complex environment, with a wide range of applications.

[0048] (3) In response to the requirements of high activity and high selectivity of the catalyst in the tritium catalytic oxidation reaction, strategies to improve the exposure of catalytic active sites, carefully design the metal-support interface, and optimize the geometric or electronic structure of the catalyst are reasonable strategies to meet the above requirements. Therefore, by adopting a step-by-step preparation method, the tritium removal catalyst prepared by the present invention can have a multi-layered structural characteristic, with a rich surface structure and porosity, so as to more efficiently adsorb and activate tritium gas molecules and expose more Pt-containing active sites. At the same time, the present invention can also construct a Pt-hydrophobic carbon interface, which can avoid the poisoning of catalytic active centers by product water molecules. In addition, there is also electron transfer between Pt and hydrophobic carbon, and the intrinsic activity of the catalyst is further improved by adjusting the d-band center position of the active metal Pt.

[0049] (4) In the process of preparing the tritium removal catalyst of the present invention, multiple structural designs are carried out. First, chloroplatinic acid is mixed with soluble starch and deionized water to obtain a mixed dispersion liquid, and then a mixed sol is obtained by adding a surfactant. After drying, a dry gel is obtained, and then a Pt nanogel is obtained through heat treatment. At this time, a preliminary catalyst prototype is already available, which mainly includes an active Pt and a nanocarbon material structure. Then, it is mixed with a modified silk fibroin powder and tetraethyl orthosilicate to obtain a composite, and then carbonization treatment is carried out to construct a two-layer composite structure. The formed complex structure can provide more active sites, thus greatly improving the catalytic efficiency and at the same time constructing a high hydrophobic property.

[0050] (5) When the tritium removal catalyst prepared by the present invention is working, once tritium gas molecules are adsorbed onto the surface of the tritium removal catalyst, they will undergo a chemical reaction with the active components on the tritium removal catalyst, thereby promoting the conversion of tritium gas molecules into tritiated water; at the same time, for the tritiated water generated after the chemical reaction of tritium gas, since the tritium removal catalyst prepared by this method has high hydrophobic properties, therefore, the tritium removal catalyst will not adsorb tritiated water, causing the tritium removal catalyst to adsorb excessive tritiated water and resulting in a significant reduction in the catalytic effect of the tritium removal catalyst. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 is a flowchart of the preparation method of the tritium removal catalyst in the embodiment of the present invention;

[0052] Figure 2 is a column chart of the water contact angle of the tritium removal catalyst prepared in the embodiment of the present invention and the tritium removal catalyst prepared in the comparative example. DETAILED DESCRIPTION OF THE INVENTION

[0053] To enable those skilled in the art to better understand the technical solutions of the present invention, the technical solutions in the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

[0054] Aiming at the problems in the prior art that the tritium removal catalyst has poor hydrophobic properties, resulting in low service life of the catalyst and low utilization rate of active sites, the present invention provides a preparation method of a tritium removal catalyst, including:

[0055] S1, adding chloroplatinic acid and soluble starch to deionized water, adjusting to a first temperature, and keeping warm and stirring to obtain a mixed dispersion;

[0056] S2, adding a composite surfactant to the mixed dispersion, adjusting the temperature to a second temperature, keeping warm and stirring to form a mixed sol;

[0057] S3, drying the mixed sol to obtain a dried gel;

[0058] S4, under the protection of an inert atmosphere, first heat-treating the dried gel and then cooling it to room temperature to obtain a Pt nanogel;

[0059] S5, adding hexafluoroisopropanol into the reaction kettle, then adding Pt nanogel, modified silk fibroin powder and tetraethyl orthosilicate, adjusting the temperature to a third temperature, keeping warm and stirring, and then drying in an oven to obtain a composite;

[0060] S6. Preheat the composite first, and then perform carbonization treatment. After cooling to room temperature, a tritium removal catalyst is obtained.

[0061] Correspondingly, the present invention also provides a tritium removal catalyst prepared by the above-described method. The surface of the catalyst particles is rough, and it has a rich microstructure of pores inside. The water contact angle reaches more than 155.5°, with good hydrophobic performance and more active sites exposed.

[0062] Example 1

[0063] As Figure 1 shown, this example discloses a preparation method of a tritium removal catalyst, including:

[0064] S1. Add chloroplatinic acid and soluble starch to deionized water respectively, adjust to the first temperature. For example, the first temperature is 80 - 90 °C. This temperature range helps to promote the full dissolution and preliminary mixing of chloroplatinic acid and soluble starch in deionized water. Keep warm and stir for 10 - 15 min to obtain a mixed dispersion.

[0065] S2. Add a composite surfactant to the mixed dispersion, adjust the temperature to the second temperature. For example, the second temperature is 75 - 78 °C. This temperature can enable the composite surfactant to play a better role. Keep warm and stir for 1 - 1.5 h, and the stirring speed is 120 - 150 r / min to form a uniform, stable and well-dispersed mixed sol.

[0066] S3. Perform drying treatment on the mixed sol to obtain a dry gel.

[0067] S4. Under the protection of an inert atmosphere, first perform heat treatment on the dry gel, and then cool it to room temperature to obtain Pt nanogel.

[0068] S5. Add hexafluoroisopropanol into the reaction kettle, then add Pt nanogel, modified silk fibroin powder and tetraethyl orthosilicate, adjust the temperature to the third temperature. For example, the third temperature is 40 - 45 °C. Keep warm in a water bath and stir for 4 h, and then place it in an oven for drying treatment. The drying treatment temperature is 60 - 65 °C, and the time is 1 - 1.2 h. This can more effectively remove the excess water and make the composite structure more stable to obtain a composite.

[0069] S6. Preheat the composite for 30 - 40 min first, and then perform carbonization treatment. After cooling to room temperature, a tritium removal catalyst with hydrophobic performance is obtained. After being detected by a contact angle meter, the water contact angle reaches more than 155.5°.

[0070] After undergoing preheating treatment and carbonization treatment in sequence, the surface of the material will exhibit a high degree of roughness and a rich microstructure of micropores. This special topological structure can make it difficult for water molecules to stay and condense on the material surface. When a water droplet contacts the material surface, due to the surface irregularities and the existence of micropores, the water droplet cannot form a continuous liquid film but is dispersed into tiny water beads or droplets. This phenomenon can effectively reduce the contact area between water and the material surface, thereby enhancing the hydrophobicity of the material.

[0071] In some embodiments, the mass ratio of chloroplatinic acid to soluble starch in step S1 is 1:12 - 14. Under this parameter, a better-performance tritium removal catalyst product can be obtained.

[0072] In some embodiments, the ratio of soluble starch to deionized water in step S1 is 14 - 18 g:120 mL to obtain a more uniform and stable mixture (i.e., a mixed dispersion).

[0073] By controlling the above dosage ratios, this method can provide a composite body with a more reasonable structure and organization before carbonization treatment, thereby ensuring a tritium removal catalyst with higher activity obtained after carbonization treatment in spent fuel reprocessing.

[0074] In some embodiments, the soluble starch in step S1 is prepared by the following steps:

[0075] S101, add starch and an ethanol solution to the reactor in sequence, adjust the temperature to the fourth temperature, and then stir to obtain a mixed solution;

[0076] S102, add a sodium hydroxide solution to the reaction kettle, adjust the pH to 11 - 11.5, adjust the temperature to the fifth temperature, keep warm, stir and react for a period of time, then add maleic anhydride, continue to stir, then add a hydrochloric acid solution to adjust the pH of the system in the reaction kettle to neutral, and finally obtain the soluble starch through rotary evaporation and drying.

[0077] By adopting the method of alkalization followed by acid anhydride modification described above, chemical changes will occur to the starch molecules. Maleic anhydride will undergo an esterification reaction with the hydroxyl groups on the starch molecules, introducing new functional groups. At the same time, different combinations of temperature and time will affect the rate and extent of the reaction. The entire preparation process of this method involves the control of multiple temperature and time parameters. For example, by controlling the fourth temperature at 40 - 45°C and the fifth temperature at 55 - 60°C, the characteristics of soluble starch in terms of molecular structure, degree of substitution, etc. can be affected, ensuring the structure and performance of soluble starch. The soluble starch prepared in this way can enable carbon atoms to penetrate into the lattice of starch molecules during subsequent carbonization treatment, replacing the original atomic positions, forming new chemical bonds and structures, manifested as a multi-porous and multi-active-site structure after carbonization, that is, forming a multi-porous structure, increasing the contact area between the catalyst and tritium, increasing the active sites, being conducive to the adsorption and reaction of tritium, promoting the conversion and removal of tritium, and thus improving the catalytic efficiency of the tritium removal catalyst.

[0078] In some embodiments, the starch in step S101 is any one of corn starch and soybean starch. Using these two starches as the carriers in the composite can improve the multi-porous structure after carbonization.

[0079] In some embodiments, the ratio of the starch in step S101 to the ethanol solution is 8 - 12 g: 100 mL.

[0080] In some embodiments, the fourth temperature in step S101 is 40 - 45°C, and the stirring time is 30 - 40 min. This is more conducive to the full mixing of starch in the ethanol solution and creates favorable conditions for subsequent reactions.

[0081] In this embodiment, the fourth temperature is preferably 40°C, and the stirring time is preferably 30 min.

[0082] In some embodiments, the concentration of the sodium hydroxide solution in step S102 is 3 - 4.

[0083] In this embodiment, the concentration of the sodium hydroxide solution is preferably 3 mol / L.

[0084] In some embodiments, the fifth temperature in step S102 is 55 - 60°C, keep warm, and the stirring reaction time is 1.5 - 2 h. This is more conducive to the full progress of relevant chemical reactions.

[0085] In this embodiment, the fifth temperature is preferably 55°C, keep warm, and the stirring reaction time is preferably 2 h.

[0086] In some embodiments, the addition amount of maleic anhydride in step S102 is 4-5% of the total mass of starch, and the continuous stirring time is 30-40 min. This addition amount and stirring time can enable maleic anhydride to fully participate in the reaction and optimize the performance of soluble starch.

[0087] In this embodiment, the addition amount of maleic anhydride is preferably 5% of the total mass of starch, and the continuous stirring time is preferably 30 min.

[0088] In some embodiments, the concentration of the hydrochloric acid solution in step S102 is 0.8-1.

[0089] In this embodiment, the concentration of the hydrochloric acid solution is preferably 1 mol / L.

[0090] By controlling the above parameters, this method can obtain soluble starch with high activity and a large content of active groups.

[0091] In some embodiments, the mass ratio of the mixed dispersion liquid to the composite surfactant in step S2 is 20:1-1.5 to improve the dispersion effect.

[0092] In some embodiments, the composite surfactant in step S2 is prepared by the following steps:

[0093] S201, Add 1-methylimidazole into the reaction kettle, introduce nitrogen gas into the reaction kettle, discharge the air in the reaction kettle, then adjust the temperature to the sixth temperature, keep it warm for 10 min, then dropwise add dodecyl chloride, continue to keep it warm, stir and react for a period of time, and then discharge to obtain an intermediate mixture;

[0094] S202, Recrystallize the intermediate mixture in ethyl acetate, then, after filtration and vacuum drying, obtain the first reactant;

[0095] S203, Mix the first reactant with sodium hydroxyethyl sulfonate to obtain the composite surfactant.

[0096] By using the composite surfactant prepared by the above method, this method can improve the colloidal stability of the mixed sol compared with conventional surfactants.

[0097] In some embodiments, the sixth temperature in step S201 is 75-80 °C, and the heat preservation time is 10-12 min, which is more conducive to the full reaction of the subsequently dropwise added dodecyl chloride with 1-methylimidazole.

[0098] In this embodiment, the sixth temperature is preferably 75 °C, and the heat preservation time is preferably 10 min.

[0099] In some embodiments, the molar ratio of 1-methylimidazole to dodecyl chloride in step S201 is 10-12:9, and the stirring reaction time is 50-55 h, so that the two can react fully to generate an ideal intermediate mixture.

[0100] In this embodiment, the molar ratio of 1-methylimidazole to dodecyl chloride is preferably 10:9.

[0101] In some embodiments, the temperature of vacuum drying in step S202 is 55 °C, and the vacuum drying time is 2 h. Under these conditions, it is possible to prevent the high-temperature drying from having a negative impact on the structure of the dried product.

[0102] In some embodiments, the mixing mass ratio of the first reactant to sodium hydroxyethyl sulfonate is 1:6-8, so that the two can be fully mixed to form a composite surfactant with excellent performance.

[0103] In some embodiments, the drying treatment of the mixed sol in step S3 is specifically as follows: drying the mixed sol at a temperature of 70-72 °C for 24-28 h. This can thoroughly achieve the purpose of drying and prevent the interference of subsequent moisture.

[0104] In some embodiments, the inert atmosphere in step S4 is a nitrogen atmosphere.

[0105] In some embodiments, the dried gel in step S4 is first heat-treated, specifically: treating at 510-520 °C for 2-3 h. Under these conditions, a carbonized structure with higher activity can be obtained.

[0106] In some embodiments, the mixing mass ratio of hexafluoroisopropanol, Pt nanogel, modified silk fibroin powder, and tetraethyl orthosilicate in step S5 is 20-25:12-14:4-6:1-1.2. Under these parameters, a composite with better structural performance can be obtained.

[0107] In some embodiments, the modified silk fibroin powder in step S5 is prepared by the following steps:

[0108] S501, adding silkworm cocoons to a mixed solution of sodium carbonate and sodium alginate, adjusting the temperature to the seventh temperature, keeping warm, stirring, filtering, and washing with water until neutral to obtain pretreated silkworm cocoons. The pretreated silkworm cocoons prepared in this way contain richer silk fibroin, which is convenient for the subsequent extraction of silk fibroin;

[0109] S502, performing a pulverization treatment on the pretreated silkworm cocoons to obtain a pulverized material of the pretreated silkworm cocoons;

[0110] S503, adding the pulverized material of the pretreated silkworm cocoons to a lithium bromide solution, adjusting the temperature to the eighth temperature, keeping warm, stirring, and then performing dialysis treatment to obtain a dialyzed material;

[0111] S504. Vacuum-dry the dialysis material to obtain the modified silk fibroin protein powder.

[0112] In some embodiments, the mass ratio of the cocoon to the mixed solution of sodium carbonate and sodium alginate is 1:10 - 12, which can make the reaction more complete.

[0113] In some embodiments, the concentration of sodium carbonate in the mixed solution of sodium carbonate and sodium alginate in step S501 is 0.01 - 0.02 mol / L, and the concentration of sodium alginate is 0.01 - 0.02 mol / L.

[0114] In this example, the concentration of sodium carbonate in the mixed solution of sodium carbonate and sodium alginate is 0.01 mol / L, and the concentration of sodium alginate is 0.01 mol / L.

[0115] In some embodiments, the seventh temperature in step S501 is 100 - 101 °C, keep warm, and the stirring time is 40 - 45 min. This can make the cocoon react fully with the mixed solution, and the prepared pretreated cocoon contains richer silk fibroin, which is convenient for the subsequent extraction of silk fibroin.

[0116] In this example, the seventh temperature is 100 °C, keep warm, and the stirring time is 40 min.

[0117] In some embodiments, the particle size of the crushed material of the pretreated cocoon in step S502 is 80 - 100 mesh. The crushing treatment can increase the specific surface area of the pretreated cocoon, which is beneficial to the subsequent reaction.

[0118] In some embodiments, the mass ratio of the lithium bromide solution to the crushed material of the pretreated cocoon in step S503 is 1:10 - 12, which can ensure the full progress of the reaction and improve the extraction efficiency of silk fibroin.

[0119] In some embodiments, the eighth temperature in step S503 is 60 - 65 °C, keep warm, and the stirring time is 2 - 2.5 h, which helps the crushed material of the pretreated cocoon react fully with the lithium bromide solution.

[0120] In this example, the eighth temperature is 60 °C, and the stirring time is 2 h.

[0121] In some embodiments, the dialysis treatment in step S503 uses a dialysis bag with a specification of 50 kDa to remove impurities smaller than 50 kDa.

[0122] In some embodiments, the temperature for vacuum-drying the dialysis material in step S504 is 50 - 60 °C, and the time is 1.5 - 2 h. This can effectively remove moisture and ensure the quality of the modified silk fibroin protein powder to remove moisture.

[0123] In this embodiment, the temperature for vacuum drying the dialysis material is 50 °C and the time is 2 h.

[0124] In some embodiments, the preheating treatment in step S6 is specifically as follows: in an air atmosphere, the composite is first heated to 400 - 420 °C at a rate of 4 - 5 °C / min, and then held for 30 - 40 min.

[0125] By performing the preheating treatment, the temperature of the composite raw material can be increased, providing a basis for the subsequent carbonization treatment reaction, facilitating the sufficiency of the subsequent carbonization treatment, and improving the quality and efficiency of the carbonization treatment.

[0126] In some embodiments, the carbonization treatment in step S6 is specifically as follows: under the protection of a nitrogen atmosphere, the preheated composite is heated to 610 - 615 °C at a heating rate of 1.5 - 2 °C / min and held for 2 - 2.5 h.

[0127] By controlling the heating rate to rise to the range of 610 - 615 °C, this method can facilitate the improvement of the reaction efficiency and carbonization quality of the carbonization treatment.

[0128] Correspondingly, this embodiment also discloses a tritium removal catalyst prepared by the above - described method. This catalyst has a rich microporous structure, a water contact angle of more than 155.5°, good hydrophobic performance, and exposes more active sites.

[0129] The applicable temperature of the tritium removal catalyst in this embodiment is 20 - 80 °C, and at this temperature, the catalytic activity is higher.

[0130] The preparation method of the tritium removal catalyst in this embodiment has the following advantages:

[0131] (1) The tritium removal catalyst prepared by this method not only has high catalytic performance and stable chemical properties, providing a strong basis for the removal of tritium gas, but also has a high specific surface area and hydrophobic performance, enabling it to have more active sites and avoiding the coverage of active sites by product water molecules. The utilization rate of active sites is high, and it can efficiently convert tritium gas into tritium water that is easy to capture, realizing the deep purification of tritium in the front - end process of spent fuel reprocessing.

[0132] (2) During the catalytic purification process of tritium gas, the tritium removal catalyst prepared by this method mainly provides active sites and reduces the reaction activation energy, thereby significantly improving the catalytic conversion rate of tritium gas. At a certain temperature, the highest catalytic conversion rate can reach nearly 100%. At the same time, due to the relatively complex structure of the tritium removal catalyst prepared by this method, it has high selectivity and stability, and can maintain the high - efficiency removal ability of tritium gas in a complex environment, with a wide range of applications.

[0133] (3) In view of the requirements for high activity and high selectivity of the catalyst in the tritium catalytic oxidation reaction, enhancing the exposure of catalytic active sites, meticulously designing the metal-support interface, and optimizing the geometric or electronic structure of the catalyst are reasonable strategies to achieve the above requirements. Therefore, through a step-by-step preparation method, the prepared tritium-removing catalyst of the present method can have a multi-level structural characteristic, with a rich surface structure and porosity, so as to more efficiently and effectively adsorb and activate tritium gas molecules and expose more Pt-containing active sites. At the same time, the present method can also construct a Pt-hydrophobic carbon interface, and by constructing the Pt-hydrophobic carbon interface, the poisoning of the catalytic active center by product water molecules can be avoided. In addition, there is also an electron transfer between Pt and hydrophobic carbon, and the intrinsic activity of the catalyst is further improved by adjusting the d-band center position of the active metal Pt.

[0134] (4) During the preparation process of the tritium-removing catalyst of the present method, multiple structural designs were carried out. First, chloroplatinic acid was mixed with soluble starch and deionized water to obtain a mixed dispersion liquid, then a surfactant was added to obtain a mixed sol, and then it was dried to obtain a dry gel. Then, through heat treatment, a Pt nanogel was obtained. At this time, a preliminary catalyst prototype was already formed, which mainly included active Pt and a nanocarbon material structure. Then, it was mixed with a modified silk fibroin powder and tetraethyl orthosilicate to obtain a composite, and then carbonization treatment was carried out to construct a two-layer composite structure. The formed complex structure can provide more active sites, thus greatly improving the catalytic efficiency and, at the same time, being able to construct a high hydrophobic property.

[0135] (5) When the tritium-removing catalyst prepared by the present method is working, once tritium gas molecules are adsorbed on the surface of the tritium-removing catalyst, they will undergo a chemical reaction with the active components on the tritium-removing catalyst, thereby promoting the conversion of tritium gas molecules into tritiated water. At the same time, for the tritiated water generated after the chemical reaction of tritium gas, because the tritium-removing catalyst prepared by the present method has a high hydrophobic property, the tritium-removing catalyst will not adsorb tritiated water, resulting in a significant reduction in the catalytic effect of the tritium-removing catalyst due to excessive adsorption of tritiated water by the tritium-removing catalyst.

[0136] Example 2

[0137] This example discloses a preparation method of a tritium-removing catalyst, and the steps include:

[0138] S1, Add chloroplatinic acid and soluble starch to deionized water respectively. The mixing mass ratio of chloroplatinic acid to soluble starch is 1:12, and the mixing ratio of soluble starch to deionized water is 14 g:120 mL. Adjust to 80 °C, keep warm, and stir for 10 min to obtain a mixed dispersion liquid.

[0139] Among them, the soluble starch is prepared by the following preparation method:

[0140] S101, Add corn starch and ethanol solution to the reaction kettle in sequence. The mixing ratio of corn starch to ethanol solution is 8g: 100mL. Adjust the temperature to 40°C, and then stir for 30 minutes to obtain a mixed solution;

[0141] S102, Then add 3mol / L sodium hydroxide solution to the reaction kettle, adjust the pH to 11.5, adjust the temperature to 55°C, keep warm, stir and react for 2h, then add maleic anhydride. The addition amount of maleic anhydride is 5% of the total mass of starch based on the total mass of starch. Continue to stir for 30 minutes, and finally use 1mol / L hydrochloric acid solution to adjust the pH of the system in the reaction kettle to neutral. After rotary evaporation and drying, soluble starch is obtained.

[0142] S2, Add a composite surfactant to the mixed dispersion. The mixing mass ratio of the mixed dispersion to the composite surfactant is 20:1. Adjust the temperature to 75°C, keep warm, stir for 1h, and the stirring speed is 120r / min to form a mixed sol.

[0143] Among them, the composite surfactant is prepared by the following preparation method:

[0144] S201, Add 1-methylimidazole to the reaction kettle, then introduce nitrogen gas into the reaction kettle to discharge the air in the reaction kettle, then adjust the temperature to 75°C, keep warm for 10 minutes, and then dropwise add dodecyl chloride. The molar ratio of 1-methylimidazole to dodecyl chloride is 10:9. Keep warm and stir and react for 50h, and then discharge to obtain an intermediate mixture;

[0145] S202, Recrystallize the intermediate mixture in ethyl acetate, then, after filtration, vacuum drying, the temperature of vacuum drying is 55°C, and the time of vacuum drying is 2h to obtain a first reactant;

[0146] S203, Mix the first reactant with sodium hydroxyethyl sulfonate. The mixing mass ratio of the first reactant to sodium hydroxyethyl sulfonate is 1:6 to obtain a composite surfactant.

[0147] S3, Perform a drying treatment on the above-mentioned mixed sol. The temperature of the drying treatment is 70°C, and the time of the drying treatment is 24h to obtain a dried gel.

[0148] S4, Under the protection of a nitrogen atmosphere, first perform a heat treatment on the above-mentioned dried gel. The heat treatment temperature is 510°C, and the heat treatment time is 2h, and then cool to room temperature to obtain Pt nanogel.

[0149] S5. Add hexafluoroisopropanol into the reaction kettle, and then add the above-mentioned Pt nanogel, modified silk fibroin powder and tetraethyl orthosilicate. The mixing mass ratio of hexafluoroisopropanol, Pt nanogel, modified silk fibroin powder and tetraethyl orthosilicate is 20:12:4:1. Adjust the temperature to 40 °C, keep it warm in a water bath, stir for 4 h, and then place it in a drying oven for drying treatment. The drying treatment temperature is 60 °C and the time is 1 h to obtain a composite.

[0150] Among them, the modified silk fibroin powder is prepared by the following preparation method:

[0151] S501. Add the cocoon into the mixed solution of sodium carbonate and sodium alginate. The mixing mass ratio of the cocoon to the mixed solution of sodium carbonate and sodium alginate is 1:10. The concentration of sodium carbonate in the mixed solution of sodium carbonate and sodium alginate is 0.01 mol / L, and the concentration of sodium alginate is 0.01 mol / L. Adjust the temperature to 100 °C, keep it warm, stir for 40 min, filter, and wash with water until neutral to obtain pretreated cocoons.

[0152] S502. Crush the pretreated cocoons to obtain a crushed material of pretreated cocoons with a particle size of 80 - 100 mesh.

[0153] S503. Add the crushed material of pretreated cocoons into the lithium bromide solution. The mass ratio of the lithium bromide solution to the crushed material of pretreated cocoons is 1:10. Adjust the temperature to 60 °C, keep it warm and stir for 2 h, and then perform dialysis treatment using a dialysis bag with a specification of 50 kDa to obtain a dialyzed material.

[0154] S504. Perform vacuum drying on the dialyzed material. The vacuum drying temperature is 50 °C and the vacuum drying time is 2 h to obtain modified silk fibroin powder.

[0155] S6. First, perform a preheating treatment on the above-mentioned composite for 30 min, and then perform a carbonization treatment. After cooling to room temperature, a deuterium removal catalyst with hydrophobic properties and applicable to the front-end deuterium removal in spent fuel reprocessing is obtained.

[0156] Among them, the preheating treatment is specifically: in an air atmosphere, first heat the composite at a rate of 4 °C / min to 400 °C, and then keep it warm.

[0157] Among them, the carbonization treatment is specifically: under the protection of a nitrogen atmosphere, heat the composite after the preheating treatment at a heating rate of 1.5 °C / min to 610 °C and keep it warm for 2 h.

[0158] Example 3

[0159] This example discloses a preparation method of a deuterium removal catalyst. The steps include:

[0160] S1. Add chloroplatinic acid and soluble starch into deionized water respectively. The mixing mass ratio of chloroplatinic acid to soluble starch is 1:13, and the mixing ratio of soluble starch to deionized water is 15 g:120 mL. Adjust the temperature to 85 °C, keep warm, and stir for 11 min to obtain a mixed dispersion.

[0161] Among them, the soluble starch is prepared by the following method:

[0162] S101. Add corn starch and ethanol solution into the reaction kettle in turn. The mixing ratio of corn starch to ethanol solution is 10 g:100 mL. Adjust the temperature to 41 °C, and then stir for 31 min to obtain a mixed solution.

[0163] S102. Then add 3.1 mol / L sodium hydroxide solution into the reaction kettle, adjust the pH to 11.4, adjust the temperature to 56 °C, keep warm, and stir and react for 1.5 h. Then add maleic anhydride. The addition amount of maleic anhydride is 4.9% of the total mass of starch based on the total mass of starch. Continue to stir for 31 min. Finally, use 0.98 mol / L hydrochloric acid solution to adjust the pH of the system in the reaction kettle to neutral. After rotary evaporation and drying, soluble starch is obtained.

[0164] S2. Add a composite surfactant to the mixed dispersion. The mixing mass ratio of the mixed dispersion to the composite surfactant is 20:1.2. Adjust the temperature to 76 °C, keep warm, and stir for 1.2 h. The stirring speed is 120 r / min to form a mixed sol.

[0165] Among them, the composite surfactant is prepared by the following method:

[0166] S201. Add 1-methylimidazole into the reaction kettle, then introduce nitrogen gas into the reaction kettle to discharge the air in the reaction kettle. Then adjust the temperature to 76 °C, keep warm for 10 min, and then dropwise add dodecyl chloride. The molar ratio of 1-methylimidazole to dodecyl chloride is 10:9. Keep warm and stir and react for 54 h, and then discharge to obtain an intermediate mixture.

[0167] S202. Recrystallize the intermediate mixture in ethyl acetate. After that, filter and vacuum dry. The temperature of vacuum drying is 55 °C, and the time of vacuum drying is 2 h to obtain the first reactant.

[0168] S203. Mix the first reactant with sodium hydroxyethyl sulfonate. The mixing mass ratio of the first reactant to sodium hydroxyethyl sulfonate is 1:6.4 to obtain a composite surfactant.

[0169] S3. Carry out drying treatment on the above mixed sol. The temperature of drying treatment is 70 °C, and the time of drying treatment is 36 h to obtain a dry gel.

[0170] S4. Under the protection of a nitrogen atmosphere, the above-mentioned dried gel is first heat-treated at a heat treatment temperature of 512 °C for 2.5 h, and then cooled to room temperature to obtain Pt nanogel.

[0171] S5. Add hexafluoroisopropanol to the reaction kettle, and then add the above-mentioned Pt nanogel, modified silk fibroin powder, and tetraethyl orthosilicate. The mixing mass ratio of hexafluoroisopropanol, Pt nanogel, modified silk fibroin powder, and tetraethyl orthosilicate is 22:13:5:1.1. Adjust the temperature to 42 °C, keep it warm in a water bath, stir for 4 h, and then place it in an oven for drying treatment. The drying treatment temperature is 60 °C and the time is 1.2 h to obtain a composite.

[0172] Among them, the modified silk fibroin powder is prepared by the following preparation method:

[0173] S501. Add the silkworm cocoons to the mixed solution of sodium carbonate and sodium alginate. The mixing mass ratio of the silkworm cocoons to the mixed solution of sodium carbonate and sodium alginate is 1:11. The concentration of sodium carbonate in the mixed solution of sodium carbonate and sodium alginate is 0.01 mol / L, and the concentration of sodium alginate is 0.01 mol / L. Adjust the temperature to 100 °C, keep it warm, stir for 41 min, filter, and wash with water until neutral to obtain pretreated silkworm cocoons.

[0174] S502. Crush the pretreated silkworm cocoons to obtain a crushed material of pretreated silkworm cocoons with a particle size of 80-100 mesh.

[0175] S503. Add the crushed material of pretreated silkworm cocoons to the lithium bromide solution. The mass ratio of the lithium bromide solution to the crushed material of pretreated silkworm cocoons is 1:10.4. Adjust the temperature to 60 °C, keep it warm and stir for 2.5 h, and then perform dialysis treatment using a dialysis bag with a specification of 50 kDa to obtain a dialyzed material.

[0176] S504. Perform vacuum drying on the dialyzed material. The temperature of the vacuum drying is 50 °C and the time of the vacuum drying is 1.5 h to obtain modified silk fibroin powder.

[0177] S6. First, preheat the above-mentioned composite for 35 min, and then perform carbonization treatment. After cooling to room temperature, a deuterium removal catalyst with hydrophobic properties that can be used for deuterium removal at the front end of spent fuel reprocessing is obtained.

[0178] Among them, the preheating treatment is specifically: under an air atmosphere, the composite is first heated to 405 °C at a rate of 4 °C / min, and then kept warm.

[0179] Among them, the carbonization treatment is specifically: under the protection of a nitrogen atmosphere, the composite after the preheating treatment is heated to 614 °C at a heating rate of 1.5 °C / min and kept warm for 2.1 h.

[0180] Example 4

[0181] This example discloses a preparation method of a tritium removal catalyst. The steps include:

[0182] S1. Add chloroplatinic acid and soluble starch into deionized water respectively. The mixing mass ratio of chloroplatinic acid to soluble starch is 1:13, and the mixing ratio of soluble starch to deionized water is 15 g:120 mL. Adjust the temperature to 86 °C, keep warm, and stir for 12 min to obtain a mixed dispersion.

[0183] Among them, the soluble starch is prepared by the following method:

[0184] S101. Add corn starch and ethanol solution into the reaction kettle in sequence. The mixing ratio of corn starch to ethanol solution is 10 g:100 mL. Adjust the temperature to 42 °C, and then stir for 32 min to obtain a mixed solution.

[0185] S102. Then add a 3.2 mol / L sodium hydroxide solution into the reaction kettle, adjust the pH to 11.3, adjust the temperature to 57 °C, keep warm, and stir and react for 1.6 h. Then add maleic anhydride. The addition amount of maleic anhydride accounts for 4.8% of the total mass of starch based on the total mass of starch. Continue to stir for 32 min. Finally, adjust the pH of the system in the reaction kettle to neutral with a 0.96 mol / L hydrochloric acid solution, and obtain soluble starch through rotary evaporation and drying.

[0186] S2. Add a composite surfactant to the mixed dispersion. The mixing mass ratio of the mixed dispersion to the composite surfactant is 20:1.3. Adjust the temperature to 76 °C, keep warm, and stir for 1.2 h. The stirring speed is 130 r / min to form a mixed sol.

[0187] Among them, the composite surfactant is prepared by the following method:

[0188] S201. Add 1-methylimidazole into the reaction kettle, then introduce nitrogen gas into the reaction kettle to discharge the air in the reaction kettle. Then adjust the temperature to 74 °C, keep warm for 10 min, and then dropwise add dodecyl chloride. The molar ratio of 1-methylimidazole to dodecyl chloride is 10:9. Keep warm and stir and react for 54 h, and then discharge to obtain an intermediate mixture.

[0189] S202. Recrystallize the intermediate mixture in ethyl acetate. After that, filter and vacuum dry. The temperature of vacuum drying is 55 °C, and the time of vacuum drying is 2 h to obtain a first reactant.

[0190] S203. Mix the first reactant with sodium 2-hydroxyethyl sulfonate at a mixing mass ratio of the first reactant to sodium 2-hydroxyethyl sulfonate of 1:6.8 to obtain a composite surfactant.

[0191] S3. Dry the above-mentioned mixed sol at a drying temperature of 70 °C for 48 h to obtain a dried gel.

[0192] S4. Under the protection of a nitrogen atmosphere, first heat-treat the above-mentioned dried gel at a heat-treatment temperature of 512 °C for 2 h, and then cool it to room temperature to obtain Pt nanogel.

[0193] S5. Add hexafluoroisopropanol to the reaction kettle, and then add the above-mentioned Pt nanogel, modified silk fibroin powder, and tetraethyl orthosilicate. The mixing mass ratio of hexafluoroisopropanol, Pt nanogel, modified silk fibroin powder, and tetraethyl orthosilicate is 23:13:5:1.2. Adjust the temperature to 41 °C, keep it warm in a water bath, stir for 4 h, and then place it in a drying oven for drying at a drying temperature of 61 °C for 1 h to obtain a composite.

[0194] Among them, the modified silk fibroin powder is prepared by the following preparation method:

[0195] S501. Add silkworm cocoons to the mixed solution of sodium carbonate and sodium alginate at a mixing mass ratio of silkworm cocoons to the mixed solution of sodium carbonate and sodium alginate of 1:11. The concentration of sodium carbonate in the mixed solution of sodium carbonate and sodium alginate is 0.01 mol / L, and the concentration of sodium alginate is 0.01 mol / L. Adjust the temperature to 100 °C, keep it warm, stir for 42 min, filter, and wash with water until neutral to obtain pretreated silkworm cocoons.

[0196] S502. Crush the pretreated silkworm cocoons to obtain a crushed material of pretreated silkworm cocoons with a particle size of 80-100 mesh.

[0197] S503. Add the crushed material of pretreated silkworm cocoons to a lithium bromide solution at a mass ratio of the lithium bromide solution to the crushed material of pretreated silkworm cocoons of 1:10.8. Adjust the temperature to 62 °C, keep it warm and stir for 2.25 h, and then perform dialysis treatment using a dialysis bag with a specification of 50 kDa to obtain a dialyzed material.

[0198] S504. Perform vacuum drying on the dialyzed material at a vacuum drying temperature of 50 °C for 1.75 h to obtain modified silk fibroin powder.

[0199] S6. First perform a preheating treatment on the above-mentioned composite for 35 min, and then perform a carbonization treatment. After cooling to room temperature, obtain a deuterium-tritium removal catalyst with hydrophobic properties that can be used for deuterium-tritium removal at the front end of spent fuel reprocessing.

[0200] Among them, the preheating treatment is specifically as follows: in an air atmosphere, the composite is first heated to 410 °C at a rate of 4 °C / min, and then kept warm, and that's it.

[0201] Among them, the carbonization treatment is specifically as follows: under the protection of a nitrogen atmosphere, the composite after the preheating treatment is heated to 614 °C at a heating rate of 1.5 °C / min and kept warm for 2.2 h.

[0202] Example 5

[0203] This example discloses a preparation method of a tritium removal catalyst, and the steps include:

[0204] S1, Add chloroplatinic acid and soluble starch to deionized water respectively. The mixing mass ratio of chloroplatinic acid to soluble starch is 1:13, and the mixing ratio of soluble starch to deionized water is 16 g:120 mL. Adjust the temperature to 88 °C, keep warm, and stir for 13 min to obtain a mixed dispersion.

[0205] Among them, the soluble starch is prepared by the following preparation method:

[0206] S101, Add corn starch and ethanol solution to the reaction kettle in sequence. The mixing ratio of corn starch to ethanol solution is 11 g:100 mL. Adjust the temperature to 43 °C, and then stir for 33 min to obtain a mixed solution;

[0207] S102, Then add a 3.3 mol / L sodium hydroxide solution to the reaction kettle, adjust the pH to 11.3, adjust the temperature to 58 °C, keep warm, stir and react for 1.7 h, then add maleic anhydride. The addition amount of maleic anhydride is calculated based on the total mass of starch and accounts for 4.7% of the total mass of starch. Continue to stir for 33 min, and finally use a 0.94 mol / L hydrochloric acid solution to adjust the pH of the system in the reaction kettle to neutral. After rotary evaporation and drying, soluble starch is obtained.

[0208] S2, Add a composite surfactant to the mixed dispersion. The mixing mass ratio of the mixed dispersion to the composite surfactant is 20:1.4. Adjust the temperature to 76 °C, keep warm, and stir for 1.2 h. The stirring speed is 135 r / min to form a mixed sol.

[0209] Among them, the composite surfactant is prepared by the following preparation method:

[0210] S201, Add 1-methylimidazole to the reaction kettle, then introduce nitrogen gas into the reaction kettle to discharge the air in the reaction kettle, then adjust the temperature to 78 °C, keep warm for 11 min, and then dropwise add dodecyl chloride. The molar ratio of 1-methylimidazole to dodecyl chloride is 11:9. Keep warm and stir and react for 54 h, and then discharge to obtain an intermediate mixture;

[0211] S202, Recrystallize the intermediate mixture in ethyl acetate. After that, filter it and conduct vacuum drying at a temperature of 55 °C for 2 h to obtain the first reactant;

[0212] S203, Mix the first reactant with sodium 2-hydroxyethanesulfonate. The mixing mass ratio of the first reactant to sodium 2-hydroxyethanesulfonate is 1:7 to obtain a composite surfactant.

[0213] S3, Conduct drying treatment on the above-mentioned mixed sol at a temperature of 71 °C for 24 h to obtain a dried gel.

[0214] S4, Under the protection of a nitrogen atmosphere, first conduct heat treatment on the above-mentioned dried gel at a heat treatment temperature of 516 °C for 2.5 h, and then cool it to room temperature to obtain Pt nanogel.

[0215] S5, Add hexafluoroisopropanol into the reaction kettle, and then add the above-mentioned Pt nanogel, modified silk fibroin powder, and tetraethyl orthosilicate. The mixing mass ratio of hexafluoroisopropanol, Pt nanogel, modified silk fibroin powder, and tetraethyl orthosilicate is 24:12:4:1.2. Adjust the temperature to 42 °C, keep it warm in a water bath, stir for 4 h, and then place it in a drying oven for drying treatment at a drying treatment temperature of 60 °C for 1 h to obtain a composite body.

[0216] Among them, the modified silk fibroin powder is prepared by the following preparation method:

[0217] S501, Add the silkworm cocoons into the mixed solution of sodium carbonate and sodium alginate. The mixing mass ratio of the silkworm cocoons to the mixed solution of sodium carbonate and sodium alginate is 1:11. The concentration of sodium carbonate in the mixed solution of sodium carbonate and sodium alginate is 0.015 mol / L, and the concentration of sodium alginate is 0.015 mol / L. Adjust the temperature to 100 °C, keep it warm, stir for 43 min, filter, and wash with water until neutral to obtain pretreated silkworm cocoons;

[0218] S502, Conduct pulverization treatment on the pretreated silkworm cocoons to obtain a pulverized material of pretreated silkworm cocoons with a particle size of 80 - 100 mesh;

[0219] S503, Add the pulverized material of pretreated silkworm cocoons into the lithium bromide solution. The mass ratio of the lithium bromide solution to the pulverized material of pretreated silkworm cocoons is 1:11. Adjust the temperature to 62 °C, keep it warm and stir for 2.5 h, and then conduct dialysis treatment using a dialysis bag with a specification of 50 kDa to obtain a dialyzed material;

[0220] S504, Conduct vacuum drying on the dialyzed material at a temperature of 54 °C for 1.5 h to obtain modified silk fibroin powder.

[0221] S6. First, preheat the above complex for 35 min, then carry out carbonization treatment. After cooling to room temperature, a tritium removal catalyst with hydrophobic properties and applicable to tritium removal at the front end of spent fuel reprocessing is obtained.

[0222] Among them, the preheating treatment is specifically as follows: In an air atmosphere, first heat the complex to 415 °C at a rate of 4.5 °C / min, and then keep it warm.

[0223] Among them, the carbonization treatment is specifically as follows: Under the protection of a nitrogen atmosphere, heat the complex after preheating treatment to 612 °C at a heating rate of 1.5 °C / min and keep it warm for 2.3 h.

[0224] Example 6

[0225] This example discloses a preparation method of a tritium removal catalyst, and the steps include:

[0226] S1. Add chloroplatinic acid and soluble starch to deionized water respectively. The mixing mass ratio of chloroplatinic acid to soluble starch is 1:14, and the mixing ratio of soluble starch to deionized water is 18 g:120 mL. Adjust to 90 °C, keep warm, and stir for 14 min to obtain a mixed dispersion.

[0227] Among them, the soluble starch is prepared by the following method:

[0228] S101. Add corn starch and ethanol solution to the reaction kettle in sequence. The mixing ratio of corn starch to ethanol solution is 12 g:100 mL. Adjust the temperature to 44 °C, and then stir for 34 min to obtain a mixed solution;

[0229] S102. Then add a 3.4 mol / L sodium hydroxide solution to the reaction kettle, adjust the pH to 11.1, adjust the temperature to 59 °C, keep warm, stir and react for 1.8 h, then add maleic anhydride. The addition amount of maleic anhydride accounts for 4.6% of the total starch mass based on the total starch mass. Continue to stir for 34 min, and finally adjust the pH of the system in the reaction kettle to neutral with a 0.92 mol / L hydrochloric acid solution. After rotary evaporation and drying, soluble starch is obtained.

[0230] S2. Add a composite surfactant to the mixed dispersion. The mixing mass ratio of the mixed dispersion to the composite surfactant is 20:1.5. Adjust the temperature to 78 °C, keep warm, stir for 1.5 h, and the stirring speed is 140 r / min to form a mixed sol.

[0231] Among them, the composite surfactant is prepared by the following method:

[0232] S201, Add 1-methylimidazole into the reaction kettle, then introduce nitrogen gas into the reaction kettle to discharge the air in the reaction kettle, and then adjust the temperature to 79 °C and keep it warm for 11 min. Then, add dodecyl chloride dropwise. The molar ratio of 1-methylimidazole to dodecyl chloride is 11:9. Keep it warm and stir for 55 h, and then discharge the material to obtain an intermediate mixture.

[0233] S202, Recrystallize the intermediate mixture in ethyl acetate. After that, filter it and dry it under vacuum. The temperature of vacuum drying is 55 °C and the time is 2 h to obtain the first reactant.

[0234] S203, Mix the first reactant with sodium 2-hydroxyethanesulfonate. The mixing mass ratio of the first reactant to sodium 2-hydroxyethanesulfonate is 1:7.2 to obtain a composite surfactant.

[0235] S3, Dry the above mixed sol. The temperature of drying treatment is 71 °C and the time is 36 h to obtain a dry gel.

[0236] S4, Under the protection of nitrogen atmosphere, first heat-treat the above dry gel. The heat-treatment temperature is 520 °C and the time is 3 h, and then cool it to room temperature to obtain Pt nanogel.

[0237] S5, Add hexafluoroisopropanol into the reaction kettle, and then add the above Pt nanogel, modified silk fibroin powder and tetraethyl orthosilicate. The mixing mass ratio of hexafluoroisopropanol, Pt nanogel, modified silk fibroin powder and tetraethyl orthosilicate is 25:14:6:1.2. Adjust the temperature to 45 °C, keep it warm in a water bath and stir for 4 h, and then place it in a drying oven for drying treatment. The drying treatment temperature is 62 °C and the time is 1 h to obtain a composite body.

[0238] Among them, the modified silk fibroin powder is prepared by the following preparation method:

[0239] S501, Add silkworm cocoons into the mixed solution of sodium carbonate and sodium alginate. The mixing mass ratio of silkworm cocoons to the mixed solution of sodium carbonate and sodium alginate is 1:12. The concentration of sodium carbonate in the mixed solution of sodium carbonate and sodium alginate is 0.015 mol / L and the concentration of sodium alginate is 0.015 mol / L. Adjust the temperature to 100 °C, keep it warm and stir for 44 min, filter it, and wash it with water until it is neutral to obtain pretreated silkworm cocoons.

[0240] S502, Crush the pretreated silkworm cocoons to obtain a crushed material of pretreated silkworm cocoons with a particle size of 80-100 mesh.

[0241] S503. Add the pretreated crushed cocoon to the lithium bromide solution. The mass ratio of the lithium bromide solution to the pretreated crushed cocoon is 1:11.2. Adjust the temperature to 64°C, keep warm and stir for 2 h, and then perform dialysis treatment using a dialysis bag with a specification of 50 kDa to obtain a dialyzed material.

[0242] S504. Vacuum-dry the dialyzed material at a temperature of 54°C for 2 h to obtain the modified silk fibroin protein powder.

[0243] S6. First, perform a preheating treatment on the above complex for 40 min, and then perform a carbonization treatment. After cooling to room temperature, a tritium removal catalyst with hydrophobic properties and applicable to the front-end tritium removal in spent fuel reprocessing is obtained.

[0244] Among them, the preheating treatment is specifically as follows: In an air atmosphere, heat the complex at a rate of 4.5°C / min to 420°C first, and then keep it warm.

[0245] Among them, the carbonization treatment is specifically as follows: Under the protection of a nitrogen atmosphere, heat the complex after the preheating treatment at a heating rate of 2°C / min to 615°C and keep it warm for 2.4 h.

[0246] Example 7

[0247] This example discloses a preparation method of a tritium removal catalyst. The steps include:

[0248] S1. Add chloroplatinic acid and soluble starch to deionized water respectively. The mixed mass ratio of chloroplatinic acid to soluble starch is 1:12, and the mixing ratio of soluble starch to deionized water is 14 g:120 mL. Adjust to 80°C, keep warm and stir for 15 min to obtain a mixed dispersion.

[0249] Among them, the soluble starch is prepared by the following method:

[0250] S101. Add corn starch and ethanol solution to the reaction kettle in sequence. The mixing ratio of corn starch to ethanol solution is 8 g:100 mL. Adjust the temperature to 45°C, and then stir for 35 min to obtain a mixed solution.

[0251] S102. Then add a 3.5 mol / L sodium hydroxide solution to the reaction kettle, adjust the pH to 11, adjust the temperature to 60°C, keep warm and stir for 1.9 h, then add maleic anhydride. The addition amount of maleic anhydride accounts for 4.5% of the total starch mass based on the total starch mass. Continue to stir for 35 min, and finally adjust the pH of the system in the reaction kettle to neutral with a 0.9 mol / L hydrochloric acid solution. After rotary evaporation and drying, soluble starch is obtained.

[0252] S2. Add a composite surfactant to the mixed dispersion liquid. The mixing mass ratio of the mixed dispersion liquid to the composite surfactant is 20:1. Adjust the temperature to 75 °C, keep it warm, and stir for 1 h at a stirring speed of 145 r / min to form a mixed sol.

[0253] Among them, the composite surfactant is prepared by the following preparation method:

[0254] S201. Add 1-methylimidazole into the reaction kettle, then introduce nitrogen gas into the reaction kettle to discharge the air in the reaction kettle. Then adjust the temperature to 80 °C, keep it warm for 11 min, and then dropwise add dodecyl chloride. The molar ratio of 1-methylimidazole to dodecyl chloride is 11:9. Keep it warm and stir for reaction for 50 h, and then discharge to obtain an intermediate mixture.

[0255] S202. Recrystallize the intermediate mixture in ethyl acetate. After that, filter it and perform vacuum drying at a temperature of 55 °C for a time of 2 h to obtain a first reactant.

[0256] S203. Mix the first reactant with sodium 2-hydroxyethylsulfonate. The mixing mass ratio of the first reactant to sodium 2-hydroxyethylsulfonate is 1:7.4 to obtain a composite surfactant.

[0257] S3. Perform drying treatment on the above-mentioned mixed sol at a temperature of 71 °C for a time of 48 h to obtain a dried gel.

[0258] S4. Under the protection of a nitrogen atmosphere, first perform heat treatment on the above-mentioned dried gel at a heat treatment temperature of 510 °C for a heat treatment time of 2 h, and then cool it to room temperature to obtain Pt nanogel.

[0259] S5. Add hexafluoroisopropanol into the reaction kettle, and then add the above-mentioned Pt nanogel, modified silk fibroin powder, and tetraethyl orthosilicate. The mixing mass ratio of hexafluoroisopropanol, Pt nanogel, modified silk fibroin powder, and tetraethyl orthosilicate is 22:13:4:1. Adjust the temperature to 40 °C, keep it warm in a water bath, and stir for 4 h. Then place it in a drying oven for drying treatment at a drying treatment temperature of 62 °C for a time of 1.2 h to obtain a composite.

[0260] Among them, the modified silk fibroin powder is prepared by the following preparation method:

[0261] S501. Add the silkworm cocoons to the mixed solution of sodium carbonate and sodium alginate. The mixing mass ratio of the silkworm cocoons to the mixed solution of sodium carbonate and sodium alginate is 1:10. The concentration of sodium carbonate in the mixed solution of sodium carbonate and sodium alginate is 0.015 mol / L, and the concentration of sodium alginate is 0.015 mol / L. Adjust the temperature to 100 °C, keep warm, stir for 45 min, filter, and wash with water until neutral to obtain pretreated silkworm cocoons.

[0262] S502. Crush the pretreated silkworm cocoons to obtain a crushed material of pretreated silkworm cocoons with a particle size of 80 - 100 mesh.

[0263] S503. Add the crushed material of pretreated silkworm cocoons to the lithium bromide solution. The mass ratio of the lithium bromide solution to the crushed material of pretreated silkworm cocoons is 1:11.4. Adjust the temperature to 64 °C, keep warm and stir for 2.25 h, and then perform dialysis treatment using a dialysis bag with a specification of 50 kDa to obtain a dialyzed material.

[0264] S504. Perform vacuum drying on the dialyzed material. The temperature of vacuum drying is 58 °C, and the time of vacuum drying is 1.75 h to obtain modified silk fibroin protein powder.

[0265] S6. First, perform preheating treatment on the above complex for 30 min, and then perform carbonization treatment. After cooling to room temperature, a deuterium - removing catalyst with hydrophobic properties and applicable to the front - end deuterium removal of spent fuel reprocessing is obtained.

[0266] Among them, the preheating treatment is specifically as follows: In an air atmosphere, first heat the complex at a rate of 4.5 °C / min to 400 °C, and then keep it warm.

[0267] Among them, the carbonization treatment is specifically as follows: Under the protection of a nitrogen atmosphere, heat the complex after preheating treatment at a heating rate of 2 °C / min to 610 °C and keep it warm for 2.5 h.

[0268] Example 8

[0269] This example discloses a preparation method of a deuterium - removing catalyst. The steps include:

[0270] S1. Add chloroplatinic acid and soluble starch to deionized water respectively. The mixing mass ratio of chloroplatinic acid to soluble starch is 1:12, and the mixing ratio of soluble starch to deionized water is 14 g:120 mL. Adjust to 80 °C, keep warm, and stir for 10 min to obtain a mixed dispersion.

[0271] Among them, the soluble starch is prepared by the following preparation method:

[0272] S101, Add corn starch and ethanol solution into the reaction kettle in sequence. The mixing ratio of corn starch to ethanol solution is 8 g: 100 mL. Adjust the temperature to 40 °C, and then stir for 30 min to obtain a mixed solution.

[0273] S102, Then add 3.6 mol / L sodium hydroxide solution into the reaction kettle, adjust the pH to 11.5, adjust the temperature to 55 °C, keep warm, stir and react for 2 h, then add maleic anhydride. The addition amount of maleic anhydride is 4.4% of the total mass of starch based on the total mass of starch. Continue to stir for 36 min, and finally adjust the pH of the system in the reaction kettle to neutral with 0.86 mol / L hydrochloric acid solution. After rotary evaporation and drying, soluble starch is obtained.

[0274] S2, Add a composite surfactant to the mixed dispersion liquid. The mixing mass ratio of the mixed dispersion liquid to the composite surfactant is 20:1. Adjust the temperature to 75 °C, keep warm, stir for 1 h, and the stirring speed is 150 r / min to form a mixed sol.

[0275] Among them, the composite surfactant is prepared by the following preparation method:

[0276] S201, Add 1-methylimidazole into the reaction kettle, then introduce nitrogen gas into the reaction kettle to discharge the air in the reaction kettle, and then adjust the temperature to 75 °C, keep warm for 12 min, then dropwise add dodecyl chloride. The molar ratio of 1-methylimidazole to dodecyl chloride is 12:9. Keep warm and stir and react for 50 h, and then discharge to obtain an intermediate mixture.

[0277] S202, Recrystallize the intermediate mixture in ethyl acetate, then, after filtration, vacuum dry. The temperature of vacuum drying is 55 °C and the time of vacuum drying is 2 h to obtain a first reactant.

[0278] S203, Mix the first reactant with sodium hydroxyethyl sulfonate. The mixing mass ratio of the first reactant to sodium hydroxyethyl sulfonate is 1:7.6 to obtain a composite surfactant.

[0279] S3, Conduct a drying treatment on the above-mentioned mixed sol. The temperature of the drying treatment is 72 °C and the time of the drying treatment is 24 h to obtain a dried gel.

[0280] S4, Under the protection of a nitrogen atmosphere, first conduct a heat treatment on the above-mentioned dried gel. The heat treatment temperature is 510 °C and the heat treatment time is 2 h, and then cool to room temperature to obtain Pt nanogel.

[0281] S5. Add hexafluoroisopropanol into the reaction kettle, and then add the above-mentioned Pt nanogel, modified silk fibroin powder and tetraethyl orthosilicate. The mixing mass ratio of hexafluoroisopropanol, Pt nanogel, modified silk fibroin powder and tetraethyl orthosilicate is 24:13:5:1.1. Adjust the temperature to 40 °C, keep it warm in a water bath, stir for 4 h, and then place it in a drying oven for drying treatment. The drying treatment temperature is 63 °C and the time is 1 h to obtain a composite.

[0282] Among them, the modified silk fibroin powder is prepared by the following preparation method:

[0283] S501. Add the silkworm cocoons into the mixed solution of sodium carbonate and sodium alginate. The mixing mass ratio of the silkworm cocoons to the mixed solution of sodium carbonate and sodium alginate is 1:10. The concentration of sodium carbonate in the mixed solution of sodium carbonate and sodium alginate is 0.02 mol / L, and the concentration of sodium alginate is 0.02 mol / L. Adjust the temperature to 101 °C, keep it warm, stir for 40 min, filter, and wash with water until neutral to obtain pretreated silkworm cocoons.

[0284] S502. Crush the pretreated silkworm cocoons to obtain a crushed material of pretreated silkworm cocoons with a particle size of 80 - 100 mesh.

[0285] S503. Add the crushed material of pretreated silkworm cocoons into the lithium bromide solution. The mass ratio of the lithium bromide solution to the crushed material of pretreated silkworm cocoons is 1:11.6. Adjust the temperature to 65 °C, keep it warm and stir for 2 h, and then perform dialysis treatment using a dialysis bag with a specification of 50 kDa to obtain a dialyzed material.

[0286] S504. Perform vacuum drying on the dialyzed material. The vacuum drying temperature is 58 °C and the vacuum drying time is 2 h to obtain modified silk fibroin powder.

[0287] S6. First, perform a preheating treatment on the above-mentioned composite for 30 min, and then perform a carbonization treatment. After cooling to room temperature, a deuterium - removing catalyst with hydrophobic properties and applicable to the front - end deuterium - removing of spent fuel reprocessing is obtained.

[0288] Among them, the preheating treatment is specifically as follows: In an air atmosphere, first heat the composite at a rate of 5 °C / min to 405 °C, and then keep it warm.

[0289] Among them, the carbonization treatment is specifically as follows: Under the protection of a nitrogen atmosphere, heat the composite after the preheating treatment at a heating rate of 2 °C / min to 610 °C and keep it warm for 2 h.

[0290] Example 9

[0291] This example discloses a preparation method of a deuterium - removing catalyst. The steps include:

[0292] S1. Add chloroplatinic acid and soluble starch to deionized water respectively. The mixing mass ratio of chloroplatinic acid to soluble starch is 1:12, and the mixing ratio of soluble starch to deionized water is 14 g:120 mL. Adjust the temperature to 80 °C, keep warm, and stir for 10 min to obtain a mixed dispersion.

[0293] Among them, the soluble starch is prepared by the following method:

[0294] S101. Add corn starch and ethanol solution to the reaction kettle in sequence. The mixing ratio of corn starch to ethanol solution is 8 g:100 mL. Adjust the temperature to 40 °C, and then stir for 30 min to obtain a mixed solution.

[0295] S102. Then add 3.8 mol / L sodium hydroxide solution to the reaction kettle, adjust the pH to 11.5, adjust the temperature to 55 °C, keep warm, and stir and react for 2 h. Then add maleic anhydride. The addition amount of maleic anhydride is 4.2% of the total mass of starch based on the total mass of starch. Continue to stir for 38 min. Finally, use 0.82 mol / L hydrochloric acid solution to adjust the pH of the system in the reaction kettle to neutral, and obtain soluble starch after rotary evaporation and drying.

[0296] S2. Add a composite surfactant to the mixed dispersion. The mixing mass ratio of the mixed dispersion to the composite surfactant is 20:1.2. Adjust the temperature to 75 °C, keep warm, and stir for 1 h. The stirring speed is 120 r / min to form a mixed sol.

[0297] Among them, the composite surfactant is prepared by the following method:

[0298] S201. Add 1-methylimidazole to the reaction kettle, then introduce nitrogen gas into the reaction kettle to discharge the air in the reaction kettle. Then adjust the temperature to 75 °C, keep warm for 12 min, and then dropwise add dodecyl chloride. The molar ratio of 1-methylimidazole to dodecyl chloride is 12:9. Keep warm and stir and react for 50 h, and then discharge to obtain an intermediate mixture.

[0299] S202. Recrystallize the intermediate mixture in ethyl acetate. After that, filter and vacuum dry. The temperature of vacuum drying is 55 °C, and the time of vacuum drying is 2 h to obtain a first reactant.

[0300] S203. Mix the first reactant with sodium hydroxyethyl sulfonate. The mixing mass ratio of the first reactant to sodium hydroxyethyl sulfonate is 1:7.8 to obtain a composite surfactant.

[0301] S3. Perform a drying treatment on the above mixed sol. The temperature of the drying treatment is 75 °C, and the time of the drying treatment is 36 h to obtain a dry gel.

[0302] S4. Under the protection of a nitrogen atmosphere, the above-mentioned dried gel is first subjected to heat treatment at a heat treatment temperature of 510 °C for 2 h, and then cooled to room temperature to obtain Pt nanogel.

[0303] S5. Add hexafluoroisopropanol into the reaction kettle, and then add the above-mentioned Pt nanogel, modified silk fibroin powder and tetraethyl orthosilicate. The mixing mass ratio of hexafluoroisopropanol, Pt nanogel, modified silk fibroin powder and tetraethyl orthosilicate is 20:12:4:1. Adjust the temperature to 40 °C, keep it warm in a water bath, stir for 4 h, and then place it in a drying oven for drying treatment. The drying treatment temperature is 64 °C and the time is 1 h to obtain a composite.

[0304] Among them, the modified silk fibroin powder is prepared by the following preparation method:

[0305] S501. Add silkworm cocoons into the mixed solution of sodium carbonate and sodium alginate. The mixing mass ratio of silkworm cocoons to the mixed solution of sodium carbonate and sodium alginate is 1:10. The concentration of sodium carbonate in the mixed solution of sodium carbonate and sodium alginate is 0.02 mol / L, and the concentration of sodium alginate is 0.02 mol / L. Adjust the temperature to 101 °C, keep it warm, stir for 43 min, filter, and wash with water until neutral to obtain pretreated silkworm cocoons.

[0306] S502. Crush the pretreated silkworm cocoons to obtain a pretreated silkworm cocoon crushed material with a particle size of 80 - 100 mesh.

[0307] S503. Add the pretreated silkworm cocoon crushed material into the lithium bromide solution. The mass ratio of the lithium bromide solution to the pretreated silkworm cocoon crushed material is 1:11.8. Adjust the temperature to 65 °C, keep it warm and stir for 2.25 h, and then perform dialysis treatment using a dialysis bag with a specification of 50 kDa to obtain a dialyzed material.

[0308] S504. Perform vacuum drying on the dialyzed material. The vacuum drying temperature is 60 °C and the vacuum drying time is 1.5 h to obtain modified silk fibroin powder.

[0309] S6. First, perform preheating treatment on the above-mentioned composite for 30 min, and then perform carbonization treatment. After cooling to room temperature, a deuterium - removing catalyst with hydrophobic properties and applicable to the front - end deuterium - removing in spent fuel reprocessing is obtained.

[0310] Among them, the preheating treatment is specifically: under an air atmosphere, first heat the composite at a rate of 5 °C / min to 415 °C, and then keep it warm.

[0311] Among them, the carbonization treatment is specifically: under the protection of a nitrogen atmosphere, heat the composite after preheating treatment at a heating rate of 5 °C / min to 610 °C and keep it warm for 2 h.

[0312] Example 10

[0313] This example discloses a preparation method of a tritium removal catalyst. The steps include:

[0314] S1. Add chloroplatinic acid and soluble starch to deionized water respectively. The mixing mass ratio of chloroplatinic acid to soluble starch is 1:12, and the mixing ratio of soluble starch to deionized water is 14 g:120 mL. Adjust the temperature to 80 °C, keep warm, and stir for 10 min to obtain a mixed dispersion.

[0315] Among them, the soluble starch is prepared by the following method:

[0316] S101. Add corn starch and ethanol solution to the reaction kettle in sequence. The mixing ratio of corn starch to ethanol solution is 8 g:100 mL. Adjust the temperature to 40 °C, and then stir for 30 min to obtain a mixed solution.

[0317] S102. Then add 4 mol / L sodium hydroxide solution to the reaction kettle, adjust the pH to 11.5, adjust the temperature to 55 °C, keep warm, and stir and react for 2 h. Then add maleic anhydride. The addition amount of maleic anhydride accounts for 4% of the total mass of starch based on the total mass of starch. Continue to stir for 40 min. Finally, adjust the pH of the system in the reaction kettle to neutral with 0.8 mol / L hydrochloric acid solution, and obtain soluble starch through rotary evaporation and drying.

[0318] S2. Add a composite surfactant to the mixed dispersion. The mixing mass ratio of the mixed dispersion to the composite surfactant is 20:1.4. Adjust the temperature to 75 °C, keep warm, and stir for 1 h. The stirring speed is 120 r / min to form a mixed sol.

[0319] Among them, the composite surfactant is prepared by the following method:

[0320] S201. Add 1-methylimidazole to the reaction kettle, then introduce nitrogen gas into the reaction kettle to discharge the air in the reaction kettle. Then adjust the temperature to 75 °C, keep warm for 12 min, and then dropwise add dodecyl chloride. The molar ratio of 1-methylimidazole to dodecyl chloride is 12:9. Keep warm and stir and react for 50 h, and then discharge to obtain an intermediate mixture.

[0321] S202. Recrystallize the intermediate mixture in ethyl acetate. After that, filter and vacuum dry. The temperature of vacuum drying is 55 °C, and the time of vacuum drying is 2 h to obtain a first reactant.

[0322] S203. Mix the first reactant with sodium hydroxyethylsulfonate. The mixing mass ratio of the first reactant to sodium hydroxyethylsulfonate is 1:8 to obtain a composite surfactant.

[0323] S3. Dry the above-mentioned mixed sol. The drying temperature is 72 °C and the drying time is 48 h to obtain a dried gel.

[0324] S4. Under the protection of a nitrogen atmosphere, first heat-treat the above-mentioned dried gel. The heat-treatment temperature is 510 °C and the heat-treatment time is 2 h, and then cool it to room temperature to obtain Pt nanogel.

[0325] S5. Add hexafluoroisopropanol into the reaction kettle, and then add the above-mentioned Pt nanogel, modified silk fibroin powder, and tetraethyl orthosilicate. The mixing mass ratio of hexafluoroisopropanol, Pt nanogel, modified silk fibroin powder, and tetraethyl orthosilicate is 20:12:4:1. Adjust the temperature to 40 °C, keep it warm in a water bath, stir for 4 h, and then place it in a drying oven for drying treatment. The drying treatment temperature is 65 °C and the time is 1.2 h to obtain a composite.

[0326] Among them, the modified silk fibroin powder is prepared by the following preparation method:

[0327] S501. Add the silkworm cocoons into the mixed solution of sodium carbonate and sodium alginate. The mixing mass ratio of the silkworm cocoons to the mixed solution of sodium carbonate and sodium alginate is 1:10. The concentration of sodium carbonate in the mixed solution of sodium carbonate and sodium alginate is 0.02 mol / L, and the concentration of sodium alginate is 0.02 mol / L. Adjust the temperature to 101 °C, keep it warm, stir for 45 min, filter, and wash with water until neutral to obtain pretreated silkworm cocoons.

[0328] S502. Crush the pretreated silkworm cocoons to obtain a crushed material of pretreated silkworm cocoons with a particle size of 80 - 100 mesh.

[0329] S503. Add the crushed material of pretreated silkworm cocoons into the lithium bromide solution. The mass ratio of the lithium bromide solution to the crushed material of pretreated silkworm cocoons is 1:12. Adjust the temperature to 65 °C, keep it warm and stir for 2.5 h, and then perform dialysis treatment using a dialysis bag with a specification of 50 kDa to obtain a dialyzed material.

[0330] S504. Perform vacuum drying on the dialyzed material. The vacuum drying temperature is 60 °C and the vacuum drying time is 2 h to obtain modified silk fibroin powder.

[0331] S6. First perform a preheating treatment on the above-mentioned composite for 30 min, and then perform a carbonization treatment. After cooling to room temperature, obtain a tritium removal catalyst with hydrophobic properties that can be used for tritium removal at the front end of spent fuel reprocessing.

[0332] Among them, the preheating treatment is specifically: under an air atmosphere, first heat the composite at a rate of 5 °C / min to 420 °C, and then keep it warm.

[0333] Among them, the carbonization treatment is specifically as follows: Under the protection of a nitrogen atmosphere, the pre-treated composite is heated to 610 °C at a heating rate of 2 °C / min and held for 2 h.

[0334] Comparative Example 1

[0335] This comparative example discloses a preparation method of a tritium removal catalyst, and the steps include:

[0336] S1, Add chloroplatinic acid and soluble starch to deionized water respectively. The mixing mass ratio of chloroplatinic acid to soluble starch is 1:12, and the mixing ratio of soluble starch to deionized water is 14 g:120 mL. Adjust to 80 °C, hold the temperature, and stir for 10 min to obtain a mixed dispersion.

[0337] Among them, the soluble starch is prepared by the following preparation method:

[0338] S101, Add corn starch and ethanol solution to the reaction kettle in sequence. The mixing ratio of corn starch to ethanol solution is 8 g:100 mL. Adjust the temperature to 40 °C, and then stir for 30 min to obtain a mixed solution;

[0339] S102, Then add a 3 mol / L sodium hydroxide solution to the reaction kettle, adjust the pH to 11.5, adjust the temperature to 55 °C, hold the temperature, and stir and react for 2 h. Then add maleic anhydride. The addition amount of maleic anhydride is 5% of the total starch mass based on the total starch mass. Continue to stir for 30 min. Finally, use a 1 mol / L hydrochloric acid solution to adjust the pH of the system in the reaction kettle to neutral. After rotary evaporation and drying, soluble starch is obtained.

[0340] S2, Add a composite surfactant to the mixed dispersion. The mixing mass ratio of the mixed dispersion to the composite surfactant is 20:1. Adjust the temperature to 75 °C, hold the temperature, and stir for 1 h. The stirring speed is 120 r / min to form a mixed sol.

[0341] Among them, the composite surfactant is prepared by the following preparation method:

[0342] S201, Add 1-methylimidazole to the reaction kettle, then introduce nitrogen gas into the reaction kettle to discharge the air in the reaction kettle. Then adjust the temperature to 75 °C, hold the temperature for 10 min, and then dropwise add dodecyl chloride. The molar ratio of 1-methylimidazole to dodecyl chloride is 10:9. Hold the temperature and stir and react for 50 h, and then discharge to obtain an intermediate mixture;

[0343] S202, Recrystallize the intermediate mixture in ethyl acetate. After that, filter and vacuum dry. The temperature of vacuum drying is 55 °C, and the time of vacuum drying is 2 h to obtain a first reactant;

[0344] S203. Mix the first reactant with sodium 2-hydroxyethanesulfonate in a mixing mass ratio of 1:6 to obtain a composite surfactant.

[0345] S3. Dry the above mixed sol at a temperature of 70 °C for 24 h to obtain a dried gel.

[0346] S4. Under the protection of a nitrogen atmosphere, first heat-treat the above dried gel at a heat-treatment temperature of 510 °C for 2 h, and then cool it to room temperature to obtain a tritium removal catalyst.

[0347] Comparative Example 2

[0348] This comparative example discloses a preparation method of a tritium removal catalyst. Compared with Example 3, the difference lies in:

[0349] On the basis of Example 3, in S5, modified silk fibroin powder is not added, and the rest of the technical solutions are the same as those in Example 3.

[0350] Comparative Example 3:

[0351] This comparative example discloses a preparation method of a tritium removal catalyst. Compared with Example 3, the difference lies in:

[0352] On the basis of Example 3, in S5, tetraethyl orthosilicate is not added, and the rest of the technical solutions are the same as those in Example 3.

[0353] Comparative Example 4:

[0354] This comparative example discloses a preparation method of a tritium removal catalyst. Compared with Example 3, the difference lies in:

[0355] On the basis of Example 3, replace soluble starch with commercially available soluble starch, which is purchased from Shandong Siyang Biotechnology Co., Ltd.

[0356] Next, test the tritium removal catalysts prepared in the above Examples 2-10 and Comparative Examples 1-4 to detect the catalytic efficiency of the tritium removal catalysts prepared in each example and comparative example.

[0357] Among them, use hydrogen as the tritium gas simulation catalytic gas in the experiment (the dosage of each group of catalysts is 100 g, and it is weighed in a clean laboratory environment with a relative humidity of 40%):

[0358] The reason why hydrogen can be used to replace tritium gas for experiments is as follows: Hydrogen and tritium gas are similar in chemical properties. Both are elemental isotopes of hydrogen and share commonalities in many catalytic reaction mechanisms. However, tritium gas is radioactive, requiring special protective facilities and strict safety measures during operation. The experimental cost is extremely high and there are significant safety risks. In contrast, hydrogen has relatively stable properties, is widely sourced and low-cost. Under simulated catalytic reaction conditions, it can effectively conduct a preliminary evaluation of the catalytic performance of the tritium-removing catalyst without involving radioactive hazards;

[0359] The tritium-removing catalyst samples prepared in Examples 2 to 10 and Comparative Examples 1 to 4 were respectively loaded into a reactor with an inner diameter of 15 mm and made of corrosion-resistant stainless steel. Then, an air inlet system was connected (air containing hydrogen as the test gas was introduced into the reactor. At a temperature of 25 °C and a pressure of 101.325 kPa, the volume fraction of hydrogen in the test air was 10%. The test gas needed to be filtered through a high-efficiency filter before being introduced into the reactor to ensure no impurity particles in the gas), and then the experiment could be carried out. Among them, the flow rate of the test gas was 10 L / min, and the flow rate was precisely controlled by a mass flow meter. The test temperature was 80 °C, and this temperature was accurately controlled by a high-precision heating jacket outside the reactor;

[0360] By carrying out catalytic reactions with the tritium-removing catalysts prepared in Examples 2 to 10 and Comparative Examples 1 to 4, the conversion rate of hydrogen was calculated. The calculation formula was:

[0361] Conversion rate = (inlet hydrogen concentration - outlet hydrogen concentration) / inlet hydrogen concentration × 100%;

[0362] Table 1

[0363] Sample Serial Number Conversion Rate (%) Example 2 99.8 Example 3 99.9 Example 4 99.8 Example 5 99.9 Example 6 99.9 Example 7 99.8 Example 8 99.8 Example 9 99.9 Example 10 99.8 Comparative Example 1 80.5 Comparative Example 2 91.6 Comparative Example 3 95.1 Comparative Example 4 93.5

[0364] As can be seen from Table 1, the catalysts prepared in the examples of the present invention have a high catalytic conversion rate for hydrogen. Since hydrogen and tritium gas are similar in chemical properties, both are elemental isotopes of hydrogen and share commonalities in many catalytic reaction mechanisms, therefore, it also has a high catalytic conversion rate for tritium gas.

[0365] Taking the tritium-removing catalyst prepared in Example 3 as the basic sample, the catalytic conversion rate of this tritium-removing catalyst for hydrogen at different temperatures is shown in Table 2 as follows:

[0366] Table 2

[0367]

[0368]

[0369] As can be seen from Table 2, the catalytic conversion rates of the tritium removal catalysts prepared by the present invention are different at different temperatures.

[0370] Next, a contact angle meter was used to measure the water contact angles of the tritium removal catalyst samples prepared in Examples 2 to 10 and Comparative Examples 1 to 4 respectively. The results are shown in Table 3, Figure 2 as follows:

[0371] Table 3

[0372] Sample Serial Number Water Contact Angle (°) Example 2 156.3 Example 3 157.2 Example 4 155.5 Example 5 156.8 Example 6 156.0 Example 7 156.9 Example 8 156.7 Example 9 156.4 Example 10 156.2 Comparative Example 1 118.3 Comparative Example 2 127.6 Comparative Example 3 131.5 Comparative Example 4 149.3

[0373] As can be seen from Table 3, Figure 2 the catalysts prepared in the examples of the present invention have high hydrophobic properties.

[0374] It can be understood that the above embodiments are merely exemplary embodiments adopted to illustrate the principles of the present invention. However, the present invention is not limited thereto. For those of ordinary skill in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also regarded as the protection scope of the present invention.

Claims

1. A method for preparing a detritus removal catalyst, comprising: S1, adding chloroplatinic acid and soluble starch into deionized water, adjusting the temperature to a first temperature, and stirring the water to obtain a mixed dispersion; S2, adding a composite surfactant to the mixed dispersion, adjusting the temperature to a second temperature, and stirring at the same temperature to form a mixed sol; S3, drying the mixed sol to obtain a dried gel; S4, under the protection of an inert atmosphere, heat-treating the dried gel, and then cooling it to room temperature to obtain a Pt nanogel; S5, adding hexafluoroisopropanol into the reaction kettle, and then adding Pt nanogel, modified silk fibroin powder and tetraethyl orthosilicate, adjusting the temperature to the third temperature, keeping the temperature, stirring, and then placing in a drying oven for drying to obtain a composite; S6, preheating the composite, then carbonizing it, and cooling it to room temperature to obtain a detritus removal catalyst.

2. The method for preparing a detritus removal catalyst according to claim 1, characterized in that: The mass ratio of the chloroplatinic acid to the soluble starch is 1:12-14.

3. The method for preparing a detritus removal catalyst according to claim 1, characterized in that: The ratio of the soluble starch to the deionized water is 14-18 g:120 mL.

4. The method for preparing a detritus removal catalyst according to claim 1, characterized in that: The first temperature is 80-90°C.

5. The method for preparing a detritus removal catalyst according to claim 1, characterized in that: The soluble starch is prepared by the following steps: S101, adding starch and ethanol solution into the reactor in sequence, adjusting the temperature to a fourth temperature, and then stirring to obtain a mixed solution; S102, add sodium hydroxide solution to the reactor, adjust the pH to 11-11.5, adjust the temperature to the fifth temperature, keep warm, stir and react for a period of time, then add maleic anhydride, continue stirring, and then add hydrochloric acid solution to adjust the pH of the system in the reactor to neutral, and finally dry it by rotary evaporation to obtain the soluble starch.

6. The method for preparing a detritus removal catalyst according to claim 5, characterized in that: The starch is any one of corn starch and soybean starch.

7. The method for preparing a detritus removal catalyst according to claim 5, characterized in that: The ratio of the starch to the ethanol solution is 8-12 g:100 mL.

8. The method for preparing a detritus removal catalyst according to claim 5, characterized in that: The fifth temperature is 55-60°C.

9. The method for preparing a detritus removal catalyst according to claim 5, characterized in that: The added amount of maleic anhydride is 4-5% of the total mass of starch.

10. The method for preparing a detritus removal catalyst according to claim 5, characterized in that: The mass ratio of the mixed dispersion to the composite surfactant is 20:1-1.

5.

11. The method for preparing a detritus removal catalyst according to claim 1, characterized in that: The composite surfactant is prepared by the following steps: S201, adding 1-methylimidazole into the reaction kettle, exhausting the air in the reaction kettle, adjusting the temperature to the sixth temperature, keeping the temperature, then adding chlorododecane dropwise, continuing to keep the temperature, stirring and reacting for a period of time, and obtaining an intermediate mixture; S202, recrystallizing the intermediate mixture in ethyl acetate, filtering, and vacuum drying to obtain a first reactant; S203, mixing the first reactant with sodium hydroxyethyl sulfonate to obtain the composite surfactant.

12. The method for preparing a detritus removal catalyst according to claim 11, characterized in that: The molar ratio of the 1-methylimidazole to the chlorododecane is 10-12:

9.

13. The method for preparing a detritus removal catalyst according to claim 1, characterized in that: The second temperature is 75-78° C., and the heat preservation and stirring time in step S2 is 1-1.5 hours.

14. The method for preparing a detritus removal catalyst according to claim 1, characterized in that: The dried gel is first subjected to heat treatment, specifically: treated at 510-520° C. for 2-3 hours.

15. The method for preparing a detritus removal catalyst according to claim 1, characterized in that: The mixing mass ratio of the hexafluoroisopropanol, the Pt nanogel, the modified silk fibroin powder and the tetraethyl orthosilicate is 20-25:12-14:4-6:1-1.

2.

16. The method for preparing a detritus removal catalyst according to claim 1, characterized in that: The modified silk fibroin powder is prepared by the following steps: S501, adding silkworm cocoons to a mixed solution of sodium carbonate and sodium alginate, adjusting the temperature to the seventh temperature, keeping the temperature, stirring, filtering, and washing with water until neutral to obtain pretreated silkworm cocoons; S502, crushing the pretreated silkworm cocoons to obtain pretreated silkworm cocoon crushed materials; S503, adding the pretreated silkworm cocoon crushed material to the lithium bromide solution, adjusting the temperature to the eighth temperature, keeping the temperature, stirring, and then dialyzing to obtain a dialyzed material; S504, vacuum drying the dialyzed material to obtain the modified silk fibroin powder.

17. The method for preparing a detritus removal catalyst according to claim 16, characterized in that: The mass ratio of the silkworm cocoon to the mixed solution of sodium carbonate and sodium alginate is 1:10-12.

18. The method for preparing a detritus removal catalyst according to claim 16, characterized in that: The mass ratio of the lithium bromide solution to the pretreated silkworm cocoon crushed material is 1:10-12.

19. The method for preparing a detritus removal catalyst according to claim 16, characterized in that: The dialysis treatment uses a dialysis bag with a specification of 50 kDa to discharge impurities smaller than 50 kDa.

20. The method for preparing a detritus removal catalyst according to claim 1, characterized in that: The third temperature is 40-45°C.

21. The method for preparing a detritus removal catalyst according to claim 1, characterized in that: The composite body is first subjected to a preheating treatment, specifically: in an air atmosphere, the composite body is first heated to 400-420° C. at a rate of 4-5° C. / min, and then kept warm for 30-40 minutes.

22. The method for preparing a detritus removal catalyst according to claim 1, characterized in that: The carbonization treatment is specifically as follows: under the protection of nitrogen atmosphere, the preheated composite body is heated to 610-615° C. at a heating rate of 1.5-2° C. / min, and kept at this temperature for 2-2.5 hours.

23. A detritus removal catalyst, characterized in that: The catalyst is prepared by the method described in any one of claims 1 to 22, the catalyst particles have a rough surface, a microscopic pore structure inside, and a water contact angle of more than 155.5°.

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