Preparation method of water rectification filler and application of water rectification filler in water isotope separation

Abstract

The invention belongs to the technical field of isotope separation, and discloses a preparation method of a water rectification filler and an application of the water rectification filler in water isotope separation.The preparation method comprises the steps that a metal matrix filler material is immersed in a modification load solution to be subjected to load treatment; the color change of the reaction solution and the color change of a load layer on the surface of the metal matrix filler material are observed, and when the reaction solution becomes light gray or grey white and the load layer on the surface of the metal matrix filler material becomes black, the reaction is stopped, and the method is efficient, simple and convenient in preparation method, high in stability, easy to prepare on a large scale and low in cost; and the prepared rectification filler has important significance for the development of the field of water isotope separation.

Description

Technical Field

[0001] The present application belongs to the technical field of isotope separation, and in particular relates to a method for preparing a water distillation filler and its application in water isotope separation. Background Art

[0002] Water isotopes include hydrogen, deuterium, tritium, oxygen-16, oxygen-17, and oxygen-18. Except for tritium, which is radioactive, the rest are stable isotopes. Water isotopes exist in different forms of oxides. The separation of water isotopes plays an important role in civil, medical diagnosis, scientific research, nuclear power, fusion research, and military fields.

[0003] The separation of hydrogen-deuterium / tritium isotopes is indispensable for the development of nuclear energy. As nuclear power is operated, a large amount of tritium wastewater will be produced, which must be properly disposed of.

[0004] The separation of water isotopes is crucial in the fields of heavy water reactor moderator purification and tritium removal. In order to maintain the stable operation of heavy water reactors, tritium purification must be carried out. In addition, tritium itself has important scientific research, economic and strategic value, and its extraction is also very necessary.

[0005] Non-radioactive water isotope separation is a key technology for the production of heavy water, oxygen-18 water, and deuterium-depleted water. Deuterium-depleted water has important research value in radiation resistance, cancer adjuvant therapy, anti-aging, metabolism enhancement and immunity improvement. Oxygen-18 is mainly used in PET / CT imaging medical diagnosis research. The production of heavy water plays an important role in the use of heavy water reactor moderators and scientific research.

[0006] Since the molecular weight difference between water isotope molecules is very small, the separation of isotopes is very difficult. As far as the existing separation methods are concerned, they mainly include electrolysis, distillation, chemical exchange, chromatography, diffusion, etc. However, as large-scale, engineering-applicable separation methods with research value, they are mainly electrolysis, chemical exchange and distillation. However, all of the above separation methods have certain problems.

[0007] Electrolysis is used to separate water isotopes. Although the CECE method can improve the separation efficiency, it requires the use of a large amount of precious metal catalysts, which are expensive and costly. At the same time, most electrolysis reactions are carried out under alkaline solution conditions, which will produce a large amount of waste liquid, bringing pressure on subsequent disposal and environmental protection. In addition, a large amount of hydrogen will be produced during the separation process, which brings huge challenges to operational safety.

[0008] Chemical exchange methods (such as water-hydrogen dual-temperature exchange method and Girdler sulfide exchange method) involve multi-temperature exchange processes and are complex to operate. Both hydrogen sulfide and ammonia raw gases are toxic and corrosive, with high investment costs and significant safety risks and environmental pollution.

[0009] The distillation method mainly includes cryogenic distillation and water distillation, both of which use the difference in vapor pressure of components to achieve separation, and the difference between components is extremely small. Regardless of the method, a large number of theoretical plates are often required to achieve separation. Although this method has disadvantages such as high energy consumption and small separation factor, it is simple to operate, has a large processing flux, and has low fixed investment and operation and maintenance costs, and is widely used in heavy water production and other fields.

[0010] For distillation method, distillation packing is one of the key cores of distillation isotope separation method. Efficient distillation packing can not only provide more theoretical plates and improve the isotope separation effect, but also reduce the height of the tower and energy consumption. Summary of the invention

[0011] The purpose of the present application is to provide a method for preparing a water distillation filler and its application in water isotope separation. In view of the problems of low separation factor and low separation effect in traditional water distillation methods, the mass transfer and heat transfer efficiency of the filler material is improved by surface modification loading method, thereby improving the separation ability of water hydrogen isotopes and promoting the development of the field of isotope distillation separation.

[0012] In order to achieve the above objectives, this application provides the following technical solutions:

[0013] In a first aspect, the present application provides a method for preparing a water distillation filler, comprising:

[0014] Step 1: Use a surface cleaning liquid to clean and dry the surface of the metal matrix filler material;

[0015] Step 2: preparing a modified loading treatment solution;

[0016] Step 3: Immerse the metal matrix filler material in the modified loading solution to carry out loading treatment, observe the color change of the reaction solution and the color change of the loading layer on the surface of the metal matrix filler material, and stop the reaction when the reaction solution turns light gray or grayish white and the surface of the metal matrix filler material load turns black;

[0017] Step 4: Remove the filler material and save it.

[0018] Preferably, the metal matrix filler material is made of a metal base material, and is selected from irregular fillers or structured fillers of different sizes.

[0019] Preferably, the irregular packing is Dixon ring, triangular spiral or Pall packing.

[0020] Preferably, the structured packing is a wire mesh corrugated packing or a plate corrugated packing.

[0021] Preferably, the surface cleaning solution is an acidic solution with an acid concentration of 0.1-2M.

[0022] Preferably, the surface cleaning liquid contains ethanol, surfactant / degreasing agent and acid, with mass / volume concentrations of 75%-95%, 2%-10%, and 0.1%-5%, respectively, and the water is pure water or ultrapure water.

[0023] Preferably, the modification components of the modification loading solution comprise a basic modifier and an oxidative modification loading agent.

[0024] Preferably, the modified loading treatment solution is prepared using an alkaline reagent and an oxidizing reagent, the concentration of the alkaline modifier is in the range of 0.5-3M, the concentration of the oxidizing modified loading agent is 0.02-1M; the molar ratio of the alkaline reagent to the oxidizing agent is 10:1-50:1.

[0025] Preferably, during load treatment, the temperature range is 293K-353K, and the time range is 10min-180min.

[0026] Preferably, the acid used in the surface cleaning solution is at least one of hydrochloric acid, nitric acid, sulfuric acid or phosphoric acid.

[0027] Preferably, the oxidative modification loading agent is a combination of one or more of sodium hydroxide, sodium phosphate, potassium hydroxide, sodium carbonate, and lithium hydroxide and at least one of ammonium persulfate, potassium persulfate, sodium persulfate, potassium permonosulfate, sodium hypochlorite, and sodium chlorite in a certain proportion.

[0028] Preferably, one or more of the irregular bulk fillers Dixon, triangular spiral, Pall fillers or wire mesh regular packed fillers are ultrasonically soaked in a dilute acid solution for 2-3 minutes; then ultrasonically soaked in a 75%-95% ethanol degreaser / surfactant solution for 5-10 minutes; then ultrasonically cleaned in pure water or ultrapure water for 10-15 minutes; the cleaned material is placed in an oven to dry for later use.

[0029] Preferably, the filler material is taken out, and repeatedly washed and dried with pure water to obtain a surface-modified loading-treated water-rectified filler, which is finally completely immersed in pure water for storage in preparation for subsequent testing.

[0030] In a second aspect, the present application provides a water distillation filler obtained by the water distillation filler preparation method.

[0031] Preferably, the water distillation filler has a nanowire, nanosheet or nanoflower-like microstructure.

[0032] Preferably, the surface of the water rectification filler has a layer of nano-sheet oxide structure with a thickness of 2-7 μm.

[0033] In a third aspect, the present application provides the use of a water distillation filler prepared by the water distillation filler preparation method in water isotope separation.

[0034] Compared with the prior art, the water distillation filler preparation method provided in the present application and its application in water isotope separation have the following beneficial effects:

[0035] The method provided in the present application is efficient, has a simple preparation method, high stability, is easy to prepare in large quantities, and has low cost. The prepared distillation filler is of great significance to the development of the field of water isotope separation.

[0036] The present application improves the mass and heat transfer efficiency of filler materials through a surface modification loading method, thereby improving the separation capability of water hydrogen isotopes and promoting the development of the field of isotope distillation separation.

[0037] The water distillation filler produced by the water distillation filler preparation method provided in the present application has a high theoretical plate number in a pilot test, and can achieve efficient separation of water isotopes.

[0038] The preparation method of water distillation filler provided in the present application can reduce the contact angle of the filler, increase the hydrophilicity, specific surface area and roughness of the filler, and is more conducive to mass transfer and heat transfer in the water distillation process, and can be applied to the field of water isotope separation. The distillation filler of the present application has significant practical and promotion value in the fields of water isotope separation and the like.

[0039] Furthermore, the raw materials of the distillation filler of the present application are widely available, the preparation process of the modified load is simple, the conditions are mild, and it is easy to prepare on a large scale. The distillation filler of the present application can achieve efficient separation of water isotopes, has no impact on the environment, and the entire process runs stably, and can be remotely controlled by a computer.

[0040] Furthermore, the two distillation packings CY700 and CY800 prepared in the present application have the best theoretical plate number. For packings of the same type, the distillation packing prepared in the present application is significantly better than commercial packings, which is 1.5-3 times the theoretical plate number of commercial packings. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to more clearly illustrate the technical solution of the present application, the following is a brief introduction to the drawings required for the technical description.

[0042] Figure 1 A flow chart of the method for preparing water distillation filler provided in this application;

[0043] Figure 2 The microscopic surface morphology SEM image of the distillation filler provided in this application;

[0044] Figure 3 Thickness diagram of the nano-oxide layer supported by the distillation filler provided in this application. DETAILED DESCRIPTION

[0045] The following is further explained in detail through specific implementation methods.

[0046] like Figure 1 As shown, the present application provides a method for preparing a water distillation filler, wherein the metal matrix filler material is pretreated and surface modified to obtain a distillation filler modified with nano-oxides, and then the prepared distillation filler is loaded into a water isotope distillation pilot test bench separation tower to measure the water isotope separation effect of the new filler. Specifically, the following steps are included:

[0047] Step 1, pretreatment step: Use a surface cleaning solution to clean the surface of the metal matrix filler material, ultrasonically remove the surface oxide layer and impurities such as oil stains, repeat 2-3 times, and then dry;

[0048] Step 2, preparing a modified loading treatment solution using an alkaline modifier and an oxidative modified loading agent;

[0049] Step 3, surface loading modification: After the pretreatment step and the modified loading treatment solution are prepared, the metal matrix filler material is immersed in the modified loading solution for loading treatment, and reacted within a certain temperature range. After a period of time, the color change of the reaction solution and the color change of the loading layer on the filler surface are observed. When the reaction solution turns light gray or grayish white and the filler surface is completely etched into black, the reaction is stopped;

[0050] Step 4: Take out the filler material, and repeatedly wash and dry it with pure water to obtain a surface-modified loaded water-rectified filler, and finally immerse it completely in pure water for storage in preparation for subsequent testing.

[0051] The metal matrix filler material is made of a metal base material and is selected from at least one of irregular fillers such as Dixon rings, triangular spirals, Pall fillers of different sizes commonly used in the chemical industry or structured fillers such as wire mesh corrugated fillers and plate corrugated fillers.

[0052] The surface cleaning solution is an acidic solution with an acid concentration of 0.1-2 M. The surface cleaning solution contains ethanol, a surfactant / degreasing agent, and an acid, etc., with mass / volume concentrations of 75%-95%, 2%-10%, and 0.1%-5%, respectively, and the water is pure water or ultrapure water.

[0053] In step 2, the main modification components of the modification loading solution include a modifier and a modification loading agent, the concentration range of the alkaline modifier is 0.5-3M, the concentration of the oxidizing agent is 0.02-1M; the molar ratio of the alkaline agent to the oxidizing agent is 10:1-50:1.

[0054] In step 3, the certain temperature range is 293K-353K; the time range is 10min-180min.

[0055] In steps 1 to 3, the acid used in the surface cleaning solution is at least one of hydrochloric acid, nitric acid, sulfuric acid or phosphoric acid, and the oxidation modification loading agent is one or more of sodium hydroxide, sodium phosphate, potassium hydroxide, sodium carbonate, and lithium hydroxide, and at least one of ammonium persulfate, potassium persulfate, sodium persulfate, potassium permonosulfate, sodium hypochlorite, and sodium chlorite, which are combined and configured in a certain proportion.

[0056] The water distillation filler prepared by the above steps has a small contact angle, a hydrophilic surface, a large specific surface area, and a nanowire or nanosheet or nanoflower-like microscopic morphology structure with a certain degree of roughness.

[0057] like Figure 2 and Figure 3 As shown, through SEM scanning electron microscopy testing, it was observed that the water distillation filler after surface modification loading treatment had a layer of nano-sheet oxide structure with a thickness of 2-7μm on the surface. At the same time, the distillation filler after treatment had a smaller contact angle and better hydrophilicity.

[0058] For example, in the water distillation test, the concentration of deuterium water used is 0.2%-5%, or the concentration of tritium wastewater is 10 8 -10 10 Bq / kg, water distillation filler is used in water isotope separation or treatment of tritium-containing wastewater in nuclear power plants.

[0059] By using the water distillation packing prepared by the present invention, under the same operating conditions, the top effluent is 50 times depleted and the bottom is 100 times concentrated relative to the feed concentration. The present invention is better than general commercial packing such as Dixon rings or stainless steel CY700 structured packing.

[0060] Example 1

[0061] First, prepare the surface-modified loaded nano-metal-based distillation filler, and the specific steps are as follows:

[0062] Prepare a pretreatment solution by mixing a small amount of acid with pure water to prepare an acidic cleaning solution with a concentration of 0.1-2M.

[0063] Take appropriate amounts of alkaline reagent and oxidizing reagent, mix them in a certain molar ratio, dissolve them in pure water, and prepare a modified loading treatment solution with a molar ratio of 10:1-50:1.

[0064] Synthesize loaded water distillation packing, take one or more of irregular bulk packing Dixon, triangular spiral, Pall packing or wire mesh regular packed packing, and soak them in dilute acid solution for 2-3 minutes by ultrasonic; then use 75%-95% ethanol degreaser / surfactant solution for ultrasonic 5-10 minutes; then ultrasonically clean in pure water or ultrapure water for 10-15 minutes; the cleaned material is placed in an oven to dry for use.

[0065] The metal material after the above pretreatment is immersed in the modified loading solution. The surface loading is carried out at room temperature 298K and normal pressure. The loading reaction time is 20min-30min and then the metal material is taken out and the surface is cleaned with ultrapure water. After cleaning, the metal material is immersed in ultrapure water for use as the distillation filler after the modification loading.

[0066] Example 2

[0067] The following describes an experiment on the water isotope separation effect of water distillation packing.

[0068] The distillation pilot test bench used in this application is a cascade distillation tower with a DN200, 3 tower sections, and a tower height of 4 meters. The bench test operating conditions (i.e., test operating conditions): reaction under certain negative pressure conditions of 5-20kPa and 60-80°C. The distillation bench test selected deuterated water with a concentration of 0.2%-5% as the feed liquid and carried out a total reflux experiment.

[0069] The selected fillers are metal wire mesh regular fillers (CY700 plain woven mesh, CY700 twill mesh, CY800 twill mesh, CY900 twill mesh and other commercial CY700 twill meshes a and b) after modified loading treatment. Sampling is carried out every 7 days, with a cycle of 25 days for distillation isotope separation verification.

[0070] The concentration of the sample is determined by water isotope mass spectrometry, infrared spectroscopy to quantify the H / D concentration, or liquid scintillation to determine the activity of tritium.

[0071] The water isotope separation effect or mass transfer efficiency in the present application is expressed by the number of theoretical plates.

[0072] Furthermore, the water distillation packing synthesized in the present application has passed a pilot bench test, and the number of theoretical plates obtained is greater than 15 plates / meter.

[0073] The following table compares the water isotope fractionation separation efficiency of different types of fillers and commercial fillers in the embodiments of the present invention.

[0074] batch Packing model Theoretical plates per meter 1 CY700-Plain Woven Net 3±0.2 2 CY700-Twill mesh-the present invention 15±0.5 3 CY-800-Twill mesh-the present invention 17.5±2.6 4 CY-900-Twill mesh-the present invention 9.5±1.0 5 a(CY700 commercial) 4.7±0.6 6 b(CY700 commercial) 10.2±1.2

[0075] It can be seen from the table that the CY700 twill mesh and CY800 twill mesh distillation packings developed by the present invention have a high theoretical plate number. For packings of the same type, the water distillation packings of the present application are also significantly better than commercial packings, which is 1.5-3 times the theoretical plate number of commercial packings. The water distillation packings of the present application have significant practical and promotion value in the fields of water isotope separation and the like.

[0076] The raw materials of the distillation filler of the present application are widely available, the preparation process of the modified load is simple, the conditions are mild, and it is easy to prepare on a large scale. The water distillation filler of the present application can achieve efficient separation of water isotopes, has no impact on the environment, and the entire process runs stably, and can be remotely controlled by a computer.

[0077] The above description is only a specific implementation manner of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by any technician familiar with the technical field within the technical scope disclosed in the present application should be covered within the protection scope of the present application.

Claims

1. A method for preparing a water distillation filler, characterized in that: include: Step 1: Use a surface cleaning liquid to clean and dry the surface of the metal matrix filler material; Step 2: preparing a modified loading treatment solution; Step 3: Immerse the metal matrix filler material in the modified loading solution to carry out loading treatment, observe the color change of the reaction solution and the color change of the loading layer on the surface of the metal matrix filler material, and stop the reaction when the reaction solution turns light gray or grayish white and the surface of the metal matrix filler material load turns black; Step 4: Remove the filler material and save it.

2. The method for preparing water distillation filler according to claim 1, characterized in that: The metal matrix filler material is made of a metal base material and is selected from irregular fillers or structured fillers of different sizes.

3. The method for preparing water distillation filler according to claim 2, characterized in that: Irregular packings include Dixon rings, triangular spirals or Pall packings.

4. The method for preparing water distillation filler according to claim 2, characterized in that: The structured packing is made of wire mesh corrugated packing or plate corrugated packing.

5. The method for preparing water distillation filler according to claim 1, characterized in that: The surface cleaning solution is an acidic solution with an acid concentration of 0.1-2M.

6. The method for preparing water distillation filler according to claim 1, characterized in that: The surface cleaning liquid contains ethanol, surfactant / degreasing agent and acid, and the mass / volume concentrations are 75%-95%, 2%-10%, and 0.1%-5% respectively, and the water is pure water or ultrapure water.

7. The method for preparing water distillation filler according to claim 1, characterized in that: The modification components of the modification loading solution include a basic modifier and an oxidative modification loading agent.

8. The method for preparing water distillation filler according to claim 1, characterized in that: The modified loading treatment solution is prepared by using an alkaline reagent and an oxidizing reagent, wherein the concentration of the alkaline modifier is in the range of 0.5-3M, and the concentration of the oxidizing modified loading agent is in the range of 0.02-1M; and the molar ratio of the alkaline modifier to the oxidizing modified loading agent is in the range of 10:1-50:

1.

9. The method for preparing water distillation filler according to claim 1, characterized in that: In step 3, during load treatment, the temperature range is 293K-353K, and the time range is 10min-180min.

10. The method for preparing water distillation filler according to claim 1, characterized in that: The acid used in the surface cleaning solution is at least one of hydrochloric acid, nitric acid, sulfuric acid or phosphoric acid.

11. The method for preparing water distillation filler according to claim 1, characterized in that: The oxidative modification loading agent is a combination of one or more of sodium hydroxide, sodium phosphate, potassium hydroxide, sodium carbonate, and lithium hydroxide and at least one of ammonium persulfate, potassium persulfate, sodium persulfate, potassium permonosulfate, sodium hypochlorite, and sodium chlorite in a certain proportion.

12. The method for preparing water distillation filler according to claim 1, characterized in that: In step 1, one or more of irregular bulk fillers such as Dixon, triangular spiral, Pall fillers or wire mesh regular packed fillers are taken and ultrasonically immersed in a dilute acid solution for 2-3 minutes; then ultrasonically immersed in a degreaser / surfactant solution of 75%-95% ethanol for 5-10 minutes; then ultrasonically cleaned in pure water or ultrapure water for 10-15 minutes; the cleaned material is placed in an oven for drying for later use.

13. The method for preparing water distillation filler according to claim 1, characterized in that: In step 4, the filler material is taken out, and is repeatedly washed and dried with pure water to obtain a surface-modified loading-treated water-rectified filler, which is finally completely immersed in pure water for storage in preparation for subsequent testing.

14. The water-rectified filler obtained by the preparation method of the water-rectified filler according to any one of claims 1 to 13.

15. The water distillation packing according to claim 14, characterized in that: The water distillation filler has a nanowire, nanosheet or nanoflower-shaped microstructure.

16. The water distillation packing according to claim 14 or 15, characterized in that: The surface of the water distillation filler has a layer of nano-sheet oxide structure with a thickness of 2-7 μm.

17. Use of the water distillation filler prepared by the method for preparing a water distillation filler according to any one of claims 1 to 13 or the water distillation filler according to any one of claims 14 to 16 in water isotope separation.

Images