A decontamination composite solution and a preparation method and application of a gel film thereof

Abstract

This invention discloses a method for preparing a detergency-removing composite solution and its gel membrane, as well as its applications. Based on the host-guest inclusion mechanism of cyclodextrin, its hydrophobic cavity is achieved by "encapsulating" hydrophobic molecules or their hydrophobic portions. The volume of the hydrophobic portion / functional group of the complexing agent molecule is smaller than the volume of the cyclodextrin cavity. The complexing agent forms a complex with cyclodextrin, thus dispersing well in the solution. Furthermore, complexing agents with good coordination ability for radioactive ions can almost always form inclusion complexes with cyclodextrin. The polysaccharide molecular chains used in this invention are rich in hydrophilic functional groups such as hydroxyl and amino groups, giving the gel membrane good hydrophilicity, low ion transport resistance, and short equilibrium time. The hydroxyl and amino functional groups also participate in the coordination process of radioactive ions, further improving the adsorption capacity of the gel membrane. The method and application of this invention have strong universality, can simultaneously remove multiple radioactive ions, and can be used on a large scale.

Description

Technical Field

[0001] This invention belongs to the field of radioactive decontamination technology, specifically relating to a decontamination composite solution and its gel membrane preparation method and application. Background Technology

[0002] During radioactive operations, spills or leaks of radioactive materials may occur due to operational or equipment malfunctions, leading to radioactive contamination of the work area. Timely and effective decontamination of contaminated surfaces (including workbenches, floors, equipment surfaces, and pipe surfaces) can reduce the radioactivity level of the work area, decrease personnel exposure doses, minimize adverse effects on equipment, and thus effectively extend the service life of radioactive facilities and equipment.

[0003] Currently, the main methods for radioactive decontamination include mechanical removal of contaminated surfaces, chemical washing, and peelable membrane decontamination. Mechanical removal involves grinding or cutting the radioactively contaminated surface and treating it as radioactive waste. This method is primarily suitable for treating contaminated floors and low-value countertops, but it easily generates radioactive dust and aerosols. Chemical washing uses solutions of large amounts of acids, alkalis, and complexing agents to clean the contaminated surface. While it has good decontamination effects, the use of large amounts of solution to wipe the surface generates a large amount of secondary waste, and it is time-consuming and exposes personnel to high radiation doses. Peelable membrane decontamination involves spraying a polymer solution that can form a film in situ onto the contaminated surface. The polymer solution also contains complexing agents that can form coordination compounds with radioactive ions. After a certain period, the radioactive material is fixed within the film, and finally, the decontamination membrane is mechanically peeled off to achieve the decontamination purpose.

[0004] However, existing commercially available peelable decontamination membrane products have extremely complex compositions, use a large number of synthetic materials and additives, are expensive, and are difficult to use on a large scale. Summary of the Invention

[0005] In view of the above-mentioned technical problems existing in the prior art, the purpose of the present invention is to provide a simple, low-cost, effective, and easily mass-producible composite solution for radioactive waste decontamination, and its gel membrane preparation method and application.

[0006] To achieve the above-mentioned objectives, the present invention adopts the following technical solution: a method for preparing a stain-removing composite solution, wherein cyclodextrin and a complexing agent are prepared into an inclusion complex solution of a certain concentration, and a certain amount of water-soluble complexing agent, sodium alginate and chitosan are added to the solution, and the solution is obtained after complete dissolution.

[0007] Furthermore, the preparation method of the stain-removing composite solution includes the following steps:

[0008] (1) Preparation of a cyclodextrin-lipid-soluble complexing agent mixed solution;

[0009] (2) A certain amount of aqueous complexing agent, sodium alginate and chitosan are added to the cyclodextrin-lipid-soluble complexing agent mixed solution. The components are stirred at a constant temperature until they are completely dissolved to obtain a cleaning composite solution.

[0010] Further, in step (1), cyclodextrin is added to water and stirred at a constant temperature to completely dissolve it to obtain an aqueous solution of cyclodextrin; a certain amount of fat-soluble complexing agent is dissolved in an organic solvent; the dissolved complexing agent solution is added dropwise to the cyclodextrin solution and kept warm for 4-36 hours to obtain a mixed solution of cyclodextrin and fat-soluble complexing agent.

[0011] Further, in step (1), the cyclodextrin is one of α-cyclodextrin, β-cyclodextrin and γ-cyclodextrin, and its mass concentration is 5-30 wt%.

[0012] Further, in step (1), the lipid-soluble complexing agent is one or more of phosphate esters, alkylphosphine oxides, carboxylic acids, methylamine oximes, crown ethers, calixarene crown ethers, and sulfonates; its amount is 0.1 to 3 times the molar amount of cyclodextrin.

[0013] Further, the organic solvent is one of methanol, ethanol, propanol, acetonitrile, DMF, and DMSO, with a mass concentration of 10–50 wt%.

[0014] Further, in step (2), the aqueous complexing agent is one or more of oxalic acid, ethylenediaminetetraacetic acid (EDTA), butanetetracarboxylic acid (BTCA), citric acid (CA), diethyltriaminepentaacetic acid (DTPA), and PTD, and its amount is 0 to 1.5 times the molar amount of cyclodextrin.

[0015] Furthermore, the sodium alginate has a mass concentration of 0.5-5 wt%, preferably 1-3 wt%.

[0016] Furthermore, the degree of deacetylation of the chitosan is greater than 60%, and the mass concentration is 0.5-5 wt%.

[0017] Furthermore, the mass concentration of the calcium salt solution is 3-10 wt%.

[0018] Furthermore, the present invention also provides a method for preparing a stain-removing composite gel membrane, wherein a prepared stain-removing composite solution is sprayed, and a solution containing divalent cations such as calcium and magnesium is sprayed on its surface to generate a composite gel membrane in situ.

[0019] The present invention also provides an application of a decontamination composite solution, which is applied to a surface of radioactive contaminants.

[0020] Furthermore, in the application of the decontamination composite gel membrane, the decontamination composite solution is sprayed onto the surface contaminated with radioactive nuclides, and after the solution has fully spread and stood still, it is wiped clean.

[0021] The present invention also provides an application of a decontamination composite gel membrane, wherein the decontamination composite gel membrane is applied to a surface of radioactive contaminants.

[0022] Furthermore, in the application of the decontamination composite gel membrane, the decontamination composite solution is sprayed onto the surface contaminated with radioactive nuclides. After the solution has spread sufficiently, a calcium salt solution with a mass concentration of 3-10 wt% is sprayed to form a decontamination composite gel membrane. After drying, the decontamination composite gel membrane is peeled off to complete the decontamination of radioactive nuclides.

[0023] The beneficial effects of adopting the technical solution of this invention are as follows: A method for preparing a detergency composite solution and its gel membrane, based on the host-guest inclusion effect of cyclodextrin, achieves its hydrophobic cavity by "encapsulating" hydrophobic molecules or the hydrophobic portion of molecules. The volume of the hydrophobic portion / functional group of the complexing agent molecule is smaller than the volume of the cyclodextrin cavity. The complexing agent and cyclodextrin form a complex, thus dispersing well in the solution. Moreover, complexing agents with good coordination ability for radioactive ions can almost always form inclusion complexes with cyclodextrin. The method and application of this invention have strong universality, can remove multiple radioactive ions simultaneously, and can be used on a large scale. The polysaccharide molecular chain used in this invention is rich in hydrophilic functional groups such as hydroxyl and amino groups, making... The gel membrane exhibits excellent hydrophilicity, low ion transport resistance, and a short equilibrium time. Furthermore, functional groups such as hydroxyl and amino groups participate in the coordination process of radioactive ions, further enhancing the adsorption capacity of the decontamination composite solution. By directly spraying the composite solution onto the surface of contaminants and then spraying a calcium-magnesium divalent cation solution to form a decontamination composite gel membrane in situ, in-situ decontamination can be achieved. On the surface of radioactive contaminants where film formation is not possible, the decontamination composite solution of this invention can be directly sprayed. The polysaccharides used in this invention, such as cyclodextrin, sodium alginate, and chitosan, have advantages such as wide availability, low cost, renewability, green and pollution-free properties, and easy degradation, effectively solving the defects of traditional peelable membranes, such as high cost, high chemical toxicity, and difficulty in degradation treatment. Detailed Implementation

[0024] The present invention will now be described in detail with reference to the embodiments.

[0025] Example 1

[0026] This invention provides a method for preparing a stain-removing composite solution. Cyclodextrin and a complexing agent are prepared into an inclusion complex solution of a certain concentration. A certain amount of water-soluble complexing agent, sodium alginate, and chitosan are added to the solution and completely dissolved to form a stain-removing composite solution.

[0027] This invention also provides a method for preparing a stain-removing composite gel membrane. Cyclodextrin and a complexing agent are prepared into an inclusion complex solution of a certain concentration. A certain amount of water-soluble complexing agent, sodium alginate and chitosan are added to the solution. After complete dissolution, the solution is sprayed. After it is fully spread, a solution containing divalent cations such as calcium and magnesium is sprayed to generate a stain-removing composite gel membrane in situ. Cyclodextrins are cyclic oligosaccharides with a unique structure and properties of "hydrophobic interior and hydrophilic exterior." Their hydrophobic interior can accommodate lipophilic / hydrophobic complexing agents, forming host-guest inclusion complexes. After inclusion, the hydrophobic complexing agent can be well dispersed in the aqueous phase. Sodium alginate is a natural polysaccharide composed of β-D-mannuronic acid and α-L-guluronic acid linked by (1→4) bonds. It undergoes irreversible gelation in the presence of divalent or hypervalent ions such as calcium and magnesium. Chitosan is an aminopolysaccharide composed of 2-amino-2-deoxy-D-glucose units linked by (1→4) bonds. It has excellent film-forming properties, and the numerous amino and hydroxyl groups on its molecular chain provide complexing sites. Cyclodextrins form inclusion complexes with sodium alginate and chitosan, exhibiting excellent metal ion coordination ability, high film-forming efficiency, and simple operation.

[0028] Preferably, the method for preparing the stain-removing composite solution includes the following steps:

[0029] (1) Preparation of a cyclodextrin-lipid-soluble complexing agent mixed solution;

[0030] (2) A certain amount of aqueous complexing agent, sodium alginate and chitosan are added to the cyclodextrin-lipid-soluble complexing agent mixed solution. The components are stirred at a constant temperature until they are completely dissolved, and a quaternary mixed solution of cyclodextrin-complexing agent-sodium alginate-chitosan is obtained, which is a cleaning composite solution.

[0031] Preferably, in step (1), cyclodextrin is added to water and stirred at a constant temperature to completely dissolve it to obtain an aqueous solution of cyclodextrin; a certain amount of fat-soluble complexing agent is dissolved in an organic solvent; the dissolved complexing agent solution is added dropwise to the cyclodextrin solution and kept warm for 4-36 hours to obtain a cyclodextrin-fat-soluble complexing agent mixed solution.

[0032] Preferably, cyclodextrin is added to water and stirred at a constant temperature of 40-90°C until completely dissolved to obtain an aqueous solution of cyclodextrin; a certain amount of fat-soluble complexing agent is dissolved in an organic solvent; and stirred at 40-80°C until dissolved.

[0033] Preferably, in step (1), the cyclodextrin is one of α-cyclodextrin, β-cyclodextrin and γ-cyclodextrin, and its mass concentration is 5-30 wt%.

[0034] Preferably, in step (1), the lipid-soluble complexing agent is one or more of phosphate esters, alkylphosphine oxides, carboxylic acids, methylamine oximes, crown ethers, calixarene crown ethers, and sulfonates; and its amount is 0.1 to 3 times the molar amount of cyclodextrin.

[0035] Preferably, the phosphate ester is one or more of tributyl phosphate (TBP), isoamyl phosphate (TiBP), di(2-ethylhexyl) phosphate (HDEHP), P,P-di(ethylhexyl)methylene diphosphonic acid (H2DEH[MDP]), and di(2,4,4-trimethylpentyl)dithiophosphonic acid (Cyanex 301).

[0036] Preferably, the alkylphosphine oxide is tri-n-octylphosphine oxide.

[0037] Preferably, the hydroxamic acid is one or more of octyl hydroxamic acid, salicylic acid, benzoyl hydroxamic acid, and tantalum reagent.

[0038] Preferably, the carboxylic acid is one or more of terephthalic acid, salicylic acid, adipic acid, octanoic acid, and dodecanoic acid.

[0039] Preferably, the amylopectin is one or more of biphenyl diamidoxime, benzylamine oxime, 2-pyridyl amylopectin, thiophene-2-amine oxime, and diacetyl oxime.

[0040] Preferably, the amide is N,N,N,N-tetraoctyl-3-oxopramidine (TODGA).

[0041] Preferably, the crown ether is one or more of 18-crown-6, dicyclohexyl-18-crown-6, dibenzo-21-crown-ether-7, and benzo-15-crown-ether-5.

[0042] Preferably, the calixarene crown ether is isopropoxycalix[4]crown-6 or n-octoxycalix[4]crown-6.

[0043] Preferably, the sulfonate is one or more of sodium dodecylbenzenesulfonate, sodium 3,3'-dioxo-[2,2'-diindolyl]-5,5'-disulfonate, and sodium benzenesulfonate.

[0044] Preferably, the organic solvent is one of methanol, ethanol, propanol, acetonitrile, DMF, and DMSO, with a mass concentration of 10–50 wt%.

[0045] Preferably, the aqueous complexing agent is one or more of oxalic acid, ethylenediaminetetraacetic acid (EDTA), butanetetracarboxylic acid (BTCA), citric acid (CA), diethyltriaminepentaacetic acid (DTPA), and PTD, and its amount is 0 to 1.5 times the molar amount of cyclodextrin.

[0046] Preferably, the sodium alginate has a mass concentration of 0.5-5 wt%, more preferably 1-3 wt%.

[0047] Preferably, the chitosan has a degree of deacetylation greater than 60% and a mass concentration of 0.5-5 wt%.

[0048] Preferably, the method for preparing the stain-removing composite gel membrane includes the following steps:

[0049] (1) Prepare the aforementioned cleaning composite solution;

[0050] (2) The cleaning composite solution is uniformly sprayed, and a solution containing divalent cations of calcium and magnesium is uniformly sprayed on its fully spread surface to form the composite gel film in situ.

[0051] Preferably, the cleaning composite solution is sprayed evenly, and after the solution has spread sufficiently, a solution containing divalent cations of calcium and magnesium with a mass concentration of 3-10 wt% is sprayed on its surface to form a cleaning composite gel film in situ.

[0052] The decontamination composite solution and its gel film preparation formula of the present invention are non-corrosive and do not generate VOCs. They have a wide range of applications and can be used for radioactive decontamination of various surfaces such as metal, glass, plastic, paint, and floor.

[0053] The preparation method of this invention does not involve complex organic reactions, and is simple, low-cost, high-performance, highly scalable, and can be mass-produced.

[0054] This invention also provides an application of a decontamination compound solution, which is applied to the surface of radioactive contaminants.

[0055] This invention also provides an application of a decontamination composite gel membrane, which is applied to the surface of radioactive contaminants.

[0056] Preferably, the application of the decontamination composite gel membrane involves spraying a decontamination solution onto a surface contaminated with radioactive nuclides. After the solution has spread sufficiently, a solution containing divalent calcium and magnesium cations with a mass concentration of 3-10 wt% is sprayed to form a decontamination composite gel membrane. After drying, the decontamination composite gel membrane is peeled off, completing the radioactive ion decontamination process. The gel membrane can be scraped off using a scraper.

[0057] Preferably, the cleaning composite gel film is air-dried or dried in hot air at 40-60°C.

[0058] This invention also provides a method for determining the detergency of a detergency composite gel membrane, comprising the following steps:

[0059] (1) Apply radioactive ions to the surface of the sample and measure the radioactivity at this time, which is recorded as A0;

[0060] (2) Spray the cleaning compound solution onto the contaminated sample;

[0061] (3) After a period of time, continue to spray calcium nitrate solution to make the cleaning compound solution gel in situ to form a film;

[0062] (4) Remove the gel membrane and test the remaining radioactivity of the sample, which is recorded as A1. The decontamination rate η of the decontamination composite gel membrane prepared in this embodiment of the invention is calculated by formula (1).

[0063]

[0064] Where A0 represents the original radioactivity and A1 represents the radioactivity after decontamination.

[0065] Example 2

[0066] The stain-removing composite solution and its gel membrane were prepared using the method described in Example 1 of this invention. 10g of α-cyclodextrin and β-cyclodextrin were added to 190mL of water, and the mixture was magnetically stirred at 80°C until it was completely dissolved. Then, 2.58g of tributyl phosphate was added to each of the two solutions, and the mixture was stirred for 24h. Then, 3g of sodium alginate and 1g of chitosan were added to each of the two solutions, and the mixture was stirred for 6h at 80°C to obtain two mixed solutions of cyclodextrin-tributyl phosphate-sodium alginate-chitosan, which are the stain-removing composite solutions.

[0067] 5 mL of the above-mentioned cleaning compound solution was sprayed onto a stainless steel plate coated with a layer of uranyl nitrate. After standing for 1 hour, 5 mL of 15 wt% calcium nitrate solution was sprayed evenly onto the stainless steel surface to form a gel film. After 24 hours, the gel film was peeled off with tweezers. The radioactivity before and after cleaning was tested, and the cleaning rate was calculated to be 96.2% and 96.6% using formula (1).

[0068] The rest is the same as in Example 1.

[0069] Example 3

[0070] The cleaning composite solution and gel membrane were prepared using the method described in Example 1 of this invention. 10g of β-cyclodextrin was added to 190mL of water and magnetically stirred at 80°C until it was completely dissolved. 3.94g of n-octylphenyl-N,N-diisobutylaminophosphine oxide (CMPO) was dissolved in 10mL of ethanol and added to the cyclodextrin solution at a rate of 0.5ml / min using a syringe pump. The mixture was stirred at 80°C for 12h. Then, 4g of sodium alginate and 1g of chitosan were added, and the mixture was stirred at 80°C for 6h to obtain a cyclodextrin-CMPO-sodium alginate-chitosan mixed solution and the cleaning composite solution.

[0071] 5 mL of the above mixed solution was sprayed onto a stainless steel plate coated with a layer of thorium nitrate, uranyl nitrate, and plutonium nitrate. After standing for 1 hour, 5 mL of 15 wt% calcium nitrate solution was sprayed evenly onto the stainless steel surface to form a gel film. After 24 hours, the gel film was peeled off with tweezers. The radioactivity before and after decontamination was tested. The decontamination rates of thorium nitrate, uranyl nitrate, and plutonium nitrate were calculated to be 97.2%, 96.7%, and 98.1%, respectively, using formula (1).

[0072] The rest is the same as in Example 1.

[0073] Example 4

[0074] The detergency-removing composite solution and gel membrane were prepared using the method described in Example 1 of this invention. 10g of β-cyclodextrin was added to 190mL of water and magnetically stirred at 80°C until completely dissolved. 0.5g of n-octylphenyl-N,N-diisobutylaminophosphine oxide (CMPO), 0.5g of tributyl phosphate, 0.5g of TODGA, 0.2g of EDTA, 0.25g of 18-crown-6, and 0.1g of sodium dodecylbenzenesulfonate were dissolved in 15mL of ethanol to form a mixed complexing agent. This agent was added to the cyclodextrin solution using a syringe pump at a rate of 0.3ml / min, and stirring was continued at 70°C for 12 hours. Then, 4g of sodium alginate and 1.5g of chitosan were added, and stirring was continued at 80°C for 6 hours to obtain a cyclodextrin-CMPO-sodium alginate-chitosan mixed solution, which is the detergency-removing composite solution.

[0075] 5 mL of the above mixed solution was sprayed onto a stainless steel plate coated with a layer of high-level radioactive waste liquid (containing radioactive uranium, plutonium, americium, cerium, praseodymium, neodymium, europium, gadolinium, strontium, cesium, and other nuclides, exhibiting strong α, β, and γ radioactivity). After standing for 2 hours, 5 mL of 15 wt% calcium nitrate solution was sprayed evenly onto the stainless steel surface to form a gel film. After 24 hours, the gel film was peeled off with tweezers. The radioactivity before and after decontamination was tested, and the decontamination rates for α, β, and γ radioactivity were calculated to be 98.5%, 92.7%, and 88.6%, respectively.

[0076] The rest is the same as in Example 1.

[0077] Example 5

[0078] A detergency composite gel membrane was prepared using the method described in Example 3. 2.61 g of biphenyl diamine oxime was used to replace the complexing agent 3.94 g of n-octylphenyl-N,N-diisobutylaminophosphine oxide (CMPO), and its detergency against uranyl nitrate was tested to be 99.6%.

[0079] The rest is the same as in Example 3.

[0080] Example 6

[0081] A detergency composite gel membrane was prepared using the method described in Example 3 of this invention. 1.48g of salicylic acid replaced 3.94g of the complexing agent n-octylphenyl-N,N-diisobutylaminophosphine oxide (CMPO), and its detergency rate against uranyl nitrate was tested to be 99.6%.

[0082] The rest is the same as in Example 3.

[0083] Example 7

[0084] The decontamination composite gel membrane was prepared using the method of Example 3 of the present invention. 0.5g tributyl phosphate, 0.5g salicylic acid, 0.5g TODGA, 0.25g EDTA, 0.2g diethyltriaminepentaacetic acid, 0.3g 18-crown-6, 0.15g n-octyloxycalix[4]crown-6 and 0.1g sodium dodecylbenzenesulfonate were combined to replace the complexing agent 3.94g n-octylphenyl-N,N-diisobutylaminephosphine oxide (CMPO). The decontamination rate against α, β and γ radioactivity was tested. The decontamination rates were calculated to be 98.8%, 95.1% and 91.3% by formula (1).

[0085] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention is also intended to include these modifications and variations.

Claims

1. A method for preparing a stain-removing composite solution, characterized in that: A solution of inclusion complex is prepared by combining cyclodextrin and a complexing agent. A water-soluble complexing agent, sodium alginate, and chitosan are then added to the solution and completely dissolved to form a detergency compound solution. This includes the following steps: (1) Preparation of a cyclodextrin-lipid-soluble complexing agent mixed solution; Add cyclodextrin to water and stir at a constant temperature until completely dissolved to obtain an aqueous solution of cyclodextrin; dissolve a fat-soluble complexing agent in an organic solvent, with the amount of fat-soluble complexing agent being 0.1 to 3 times the molar amount of cyclodextrin; add the dissolved fat-soluble complexing agent solution dropwise to the cyclodextrin solution and continue to keep warm for 4-36 hours to obtain a mixed solution of cyclodextrin and fat-soluble complexing agent; (2) Add aqueous complexing agent, sodium alginate and chitosan to the cyclodextrin-lipid-soluble complexing agent mixed solution. The amount of aqueous complexing agent is less than or equal to 1.5 times the molar amount of cyclodextrin. Stir at constant temperature until the components are completely dissolved to obtain a quaternary mixed solution of cyclodextrin-complexing agent-sodium alginate-chitosan, which is a cleaning composite solution.

2. The method for preparing a stain-removing composite solution according to claim 1, characterized in that: In step (1), the cyclodextrin is one of α-cyclodextrin, β-cyclodextrin and γ-cyclodextrin, and its mass concentration is 5-30 wt%.

3. The method for preparing a stain-removing composite solution according to claim 1, characterized in that: In step (1), the lipid-soluble complexing agent is one or more of the following: phosphate ester, alkylphosphine oxide, carboxylic acid, amine oxime, crown ether, calixarene crown ether, and sulfonate.

4. The method for preparing a stain-removing composite solution according to claim 1, characterized in that: The chitosan has a degree of deacetylation greater than 60% and a mass concentration of 0.5-5 wt%.

5. An application of a stain-removing composite solution, characterized in that: The decontamination composite solution prepared by any one of claims 1-4 is applied to the decontamination of radioactive contaminant surfaces.

6. The application of the stain-removing composite solution according to claim 5, characterized in that: The cleaning composite solution is sprayed onto the surface of the item, and after it is fully spread, a solution containing divalent calcium and magnesium cations is sprayed on it to generate a composite gel film in situ.

7. The application of the stain-removing composite solution according to claim 6, characterized in that: The decontamination composite solution is sprayed onto the surface contaminated with radioactive nuclides. After the solution has spread sufficiently, a calcium and magnesium divalent cation salt solution with a mass concentration of 3-10 wt% is sprayed to form a decontamination composite gel film in situ. After drying, the decontamination composite gel film is peeled off to complete the decontamination of radioactive nuclides.

8. The application of the stain-removing composite solution according to claim 7, characterized in that: The cleaning composite gel membrane can be air-dried or dried with hot air at 40-60ºC.

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