Vacuum low-temperature extraction process for low deuterium water

Abstract

The application discloses a kind of vacuum low-temperature extraction low deuterium water process, belong to water treatment technical field.The method is heated to water under vacuum environment and evaporates, using the evaporation temperature difference of deuterium and water, realize the effective separation of water and deuterium.By adjusting vacuum degree and evaporation temperature, the deuterium content of low deuterium water can be accurately controlled, so that low deuterium water products with different deuterium content can be produced to meet the diversified needs of the market.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of water treatment, and in particular to a process for extracting low-deuterium water at low temperature under vacuum. BACKGROUND

[0002] Low-deuterium water, also known as deuterium depleted water (DDW), is a kind of water with low deuterium content. Deuterium is an isotope of hydrogen, also known as heavy hydrogen. In nature, the content of deuterium is about 0.015%, and low-deuterium water is obtained by extracting deuterium from water which is harmful to human body, thereby reducing the deuterium content of water.

[0003] The main feature of low-deuterium water is that the deuterium content in water is lower than that of general drinking water, and it is a kind of high-quality water beneficial to human health. Drinking low-deuterium pure water is to reduce the concentration of deuterium in the human body by diluting deuterium, and help to repair metabolic function. Long-term drinking of low-deuterium pure water is of great significance to maintaining good health.

[0004] A system for producing ultra-low deuterium water (Chinese patent application number: CN202311540225.1) includes a feed unit, a first electrolytic catalytic exchange unit and a second electrolytic catalytic exchange unit. The feed unit includes a hydrogen source and a water source. The first electrolytic catalytic exchange unit is in communication with the feed unit. The natural hydrogen source and the natural water source are used to provide hydrogen and water for the first electrolytic catalytic exchange unit. The hydrogen and water from the outside carry out water-hydrogen isotope exchange reaction in the first electrolytic catalytic exchange unit, and generate low-deuterium water. The second electrolytic catalytic exchange unit is connected in series with the first electrolytic catalytic exchange unit. The low-deuterium water generated in the first electrolytic catalytic exchange unit enters the second electrolytic catalytic exchange unit to carry out water-hydrogen isotope exchange reaction, and generates ultra-low deuterium water.

[0005] An integrated ultra-low deuterium water preparation device (Chinese patent application number: CN202311537110.7) includes at least two electrolytic catalytic exchange units, two electrolytic catalytic exchange units are connected in series, an external water source is in communication with one of the electrolytic catalytic exchange units, and enters the electrolytic catalytic exchange unit to generate low-deuterium water, and the low-deuterium water enters the other electrolytic catalytic exchange unit to generate ultra-low deuterium water. The electrolytic catalytic exchange unit includes a catalytic exchange assembly, a water electrolysis assembly and a hydrogen fuel cell assembly. The hydrogen and water entering the catalytic exchange assembly can carry out water-hydrogen isotope exchange reaction in the catalytic exchange assembly, and generate low-deuterium hydrogen or ultra-low deuterium hydrogen. The water in the catalytic exchange assembly flows into the water electrolysis assembly, and generates hydrogen and oxygen by electrolysis in the water electrolysis assembly.

[0006] A kind of low deuterium water production equipment (Chinese patent application number: CN201810486310.7) including pure water storage device, electrolytic composite unit, high deuterium water generation unit and low deuterium water generation unit;Pure water storage device is communicated with electrolytic composite unit by pure water delivery pipeline;Electrolytic composite unit is externally connected with power supply;High deuterium water generation unit includes primary gas-liquid separation device and high deuterium water storage unit communicated with primary gas-liquid separation device;Low deuterium water generation unit includes secondary gas-liquid separation device and low deuterium water storage unit communicated with secondary gas-liquid separation device.

[0007] Traditional low deuterium water extraction method has problems such as low efficiency, high cost, complex operation and difficult to control deuterium content.With the increase of demand for low deuterium water, the market urgently needs an efficient and low-cost low deuterium water extraction technology. SUMMARY

[0008] In view of the problems pointed out in the background art and the deficiencies existing in the prior art, the purpose of the present application is to provide a vacuum low-temperature extraction process for low deuterium water, which realizes the effective separation of water and deuterium by vacuum environment and accurate temperature control, and produces low deuterium water products with different deuterium contents.

[0009] The above invention is realized by the following scheme:

[0010] A vacuum low-temperature extraction process for low deuterium water, the operation steps are:

[0011] Step one: according to mass fraction, 1000-3000 parts of water are introduced into the reaction kettle according to mass fraction, ensure that the reaction kettle is well sealed, avoid water vapor leakage, start the stirring system, and ensure that the water is evenly distributed in the reaction kettle;

[0012] Step two: start the vacuum pump to vacuumize the reaction kettle, reach the predetermined vacuum degree, and gradually heat the water temperature in the reaction kettle to the evaporation temperature by the heat conducting oil heating system.

[0013] Step three: the water vapor generated in the reaction kettle is filtered by the membrane filter and transported to the condenser through the high-purity pipeline, in the condenser, the water vapor encounters the cooling surface and is quickly condensed into liquid water, i.e. low deuterium water.

[0014] In the present application, the stirring speed in step one is 30-60 rpm.

[0015] In the present application, the vacuum degree of the reaction kettle in step two is 0.01-1 Pa.

[0016] In the present application, the evaporation temperature of the reaction kettle in step two is 50-85℃.

[0017] In the present application, the high-purity pipeline in step three is a high-purity PFA pipeline.

[0018] In the present application, the membrane filter in step three adopts an organometallic framework material mixed matrix membrane, comprising the following steps:

[0019] A: According to weight parts, 21-42 parts of 4-mercapto pyridine dicarboxylic acid and 23-46 parts of zirconium chloride are mixed, and then magnetically stirred for 5-15 min. After that, it is put into an autoclave and reacted at 90-100℃ for 10-22h. After cooling, the mixture is soaked in 100-150 parts of DMF for 20-40 min, and the solid product is collected by centrifugation. Then it is washed with ultrapure water and ethanol for three times, and then vacuum dried at 60-70℃ for 10-15h to obtain the mercapto MOF material.

[0020] B: According to weight parts, 20-40 parts of mercapto MOF material powder is dispersed in 500-650 parts of acetone, and ultrasonic treatment is carried out for 20-40 min. Then 2-5 parts of PVDF, 0.02-0.5 parts of maleic anhydride polyether ester resin, 0.02-0.5 parts of vinyl pyridine-nickel, and 0.02-0.5 parts of sodium ethoxide are added, and ultrasonic treatment is carried out for 10-50 min. The acetone is blown dry with nitrogen, and the obtained mixture is uniformly coated on a circular glass substrate. The solvent is removed by distillation, and dried in air to obtain an organometallic framework material mixed matrix membrane.

[0021] The membrane reaction mechanism is as follows:

[0022] The mercapto MOF material undergoes a mercapto-ene addition reaction with the maleic anhydride polyether ester resin, and the vinyl group (C=C) in the formed vinyl pyridine-nickel complex undergoes a mercapto-ene addition reaction with the remaining mercapto group (-SH) of the mercapto MOF material, thereby fixing the pyridine-nickel complex to the polyether ester skeleton.

[0023] Technical effects:

[0024] 1. The present method effectively reduces the production cost, is simple to operate, and is easy to realize large-scale production. The deuterium content of the low deuterium water can be flexibly adjusted according to market demand.

[0025] 2. Optimizing the material structure: ensuring that the pore size and shape of the MOF material are selectively suitable for the size and shape of the deuterium molecule, so as to enhance the selective adsorption of deuterium / hydrogen. Controlling the density and distribution of the pyridine-nickel complex, and adjusting the electronic and spatial environment of the pyridine-nickel complex by using zirconium metal ion ligand, so as to improve its selectivity to deuterium.

[0026] 3. Adjusting the addition reaction of polyether ester to improve the mechanical properties and stability of the membrane. DETAILED DESCRIPTION

[0027] It should be noted that the embodiments in the present application and the technical features in the embodiments can be combined with each other without conflict, and the detailed description in the specific implementation should be understood as the explanation and illustration of the purpose of the present application, and should not be regarded as improper limitation on the present application.

[0028] The low deuterium water prepared in the embodiments of the present application determines the content of deuterium by measuring the proportion of hydrogen isotopes in water molecules by mass spectrometry.

[0029] Embodiment 1

[0030] A vacuum low-temperature extraction process for low deuterium water, the operation steps of which are as follows:

[0031] Step one: 1000g of water is introduced into the reaction kettle according to the mass fraction, the sealing property of the reaction kettle is ensured to avoid the leakage of water vapor, the stirring system is started to ensure the uniform distribution of water in the reaction kettle;

[0032] Step two: start the vacuum pump to perform vacuum treatment on the reaction kettle, reach the predetermined vacuum degree, and gradually increase the water temperature in the reaction kettle to the evaporation temperature through the heat conduction oil heating system;

[0033] Step three: the water vapor generated in the reaction kettle is filtered through a membrane filter and then transported to a condenser through a high-purity pipeline. In the condenser, the water vapor encounters a cooling surface and is rapidly condensed into liquid water, i.e. low deuterium water.

[0034] The stirring speed in step one is 30 rpm.

[0035] The vacuum degree of the reaction kettle in step two is 1 Pa.

[0036] The evaporation temperature of the reaction kettle in step two is 85℃.

[0037] The high-purity pipeline in step three is a high-purity PFA pipeline.

[0038] The membrane filter in step three uses an organic metal framework material mixed matrix membrane, which comprises the following steps:

[0039] A: 21g of 4-mercaptopyridine dicarboxylic acid and 23g of zirconium chloride are mixed, magnetically stirred for 5min, then put into an autoclave and reacted at 90℃ for 10h; after cooling, the mixture is soaked in 100g of DMF for 20min, and the solid product is collected by centrifugation; washed with ultrapure water and ethanol three times each, and then vacuum dried at 60℃ for 10h to prepare a mercapto MOF material;

[0040] B: 20 g of thiol MOF material powder was dispersed in 500 g of acetone, and ultrasonic treatment was performed for 20 min; 2 g of PVDF, 0.02 g of maleic anhydride polyether ester resin, 0.02 g of vinylpyridine-nickel, and 0.02 g of sodium ethoxide were added, and ultrasonic treatment was performed for 10 min; the acetone was blown dry with nitrogen, and the obtained mixture was uniformly coated on a circular glass substrate, and the solvent was removed by distillation, and dried in air to obtain an organometallic framework material mixed matrix film.

[0041] The deuterium content of the low-deuterium water prepared in the embodiment was 65 ppm through analysis test.

[0042] Example 2

[0043] A vacuum low-temperature extraction process for low-deuterium water, the operation steps of which are as follows:

[0044] Step one: 2000 g of water was introduced into the reaction kettle according to the mass fraction, the sealing performance of the reaction kettle was ensured to avoid the leakage of water vapor, the stirring system was started to ensure the uniform distribution of water in the reaction kettle;

[0045] Step two: the vacuum pump was started to perform vacuum treatment on the reaction kettle, and the water temperature in the reaction kettle was gradually increased to the evaporation temperature through the heat conduction oil heating system after reaching the predetermined vacuum degree;

[0046] Step three: the water vapor generated in the reaction kettle was filtered through a membrane filter and then transported to a condenser through a high-purity pipeline, and the water vapor was rapidly condensed into liquid water, i.e., low-deuterium water, when it encountered a cooling surface in the condenser.

[0047] The stirring speed in step one is 40 rpm.

[0048] The vacuum degree of the reaction kettle in step two is 0.1 Pa.

[0049] The evaporation temperature of the reaction kettle in step two is 65℃.

[0050] The high-purity pipeline in step three is a high-purity PFA pipeline.

[0051] The membrane filter in step three is an organometallic framework material mixed matrix film, which comprises the following steps:

[0052] A: 28 g of 4-mercaptopyridine dicarboxylic acid and 30 g of zirconium chloride were mixed, and magnetic stirring was performed for 10 min, and then the mixture was placed in an autoclave and reacted at 90℃ for 14 h; after cooling, the mixture was soaked in 115 g of DMF for 30 min, and the solid product was collected by centrifugation; the solid product was washed with ultrapure water and ethanol three times, and then vacuum dried at 60℃ for 12 h to obtain a thiol MOF material;

[0053] B: 30 g of thiol MOF material powder was dispersed in 550 g of acetone, and ultrasonic treatment was performed for 30 min; 3 g of PVDF, 0.2 g of maleic anhydride polyether ester resin, 0.2 g of vinylpyridine-nickel, and 0.2 g of sodium ethoxide were added, and ultrasonic treatment was performed for 25 min; the acetone was blown dry with nitrogen, and the obtained mixture was uniformly coated on a circular glass substrate, and the solvent was removed by distillation, and dried in air to obtain an organometallic framework material mixed matrix film.

[0054] The deuterium content of the low-deuterium water prepared in the embodiment is 50 ppm through analysis test.

[0055] Example 3

[0056] A vacuum low-temperature extraction process for low-deuterium water, the operation steps of which are as follows:

[0057] Step one: 2000 g of water was introduced into the reaction kettle according to the mass fraction, the sealing performance of the reaction kettle was ensured to avoid water vapor leakage, the stirring system was started to ensure uniform distribution of water in the reaction kettle;

[0058] Step two: the vacuum pump was started to perform vacuum treatment on the reaction kettle, and the water temperature in the reaction kettle was gradually increased to the evaporation temperature through the heat conduction oil heating system when the predetermined vacuum degree was reached;

[0059] Step three: the water vapor generated in the reaction kettle was filtered through a membrane filter and then transported to a condenser through a high-purity pipeline, and the water vapor was rapidly condensed into liquid water, i.e., low-deuterium water, when it encountered a cooling surface in the condenser.

[0060] The stirring speed in step one is 50 rpm.

[0061] The vacuum degree of the reaction kettle in step two is 0.05 Pa.

[0062] The evaporation temperature of the reaction kettle in step two is 55℃.

[0063] The high-purity pipeline in step three is a high-purity PFA pipeline.

[0064] The membrane filter in step three is an organometallic framework material mixed matrix film, which comprises the following steps:

[0065] A: 34 g of 4-mercapto pyridine dicarboxylic acid and 38 g of zirconium chloride were mixed, and magnetic stirring was performed for 10 min, and then the mixture was placed in an autoclave and reacted at 100℃ for 18 h; after cooling, the mixture was soaked in 130 g of DMF for 30 min, and the solid product was collected by centrifugation; the solid product was washed with ultrapure water and ethanol three times, and then vacuum dried at 70℃ for 14 h to obtain a thiol MOF material;

[0066] B: 30 g of thiol MOF material powder was dispersed in 600 g of acetone, and ultrasonic treatment was performed for 30 min; 4 g of PVDF, 0.4 g of maleic anhydride polyether ester resin, 0.4 g of vinylpyridine-nickel, and 0.4 g of sodium ethoxide were added, and ultrasonic treatment was performed for 40 min; the acetone was blown dry with nitrogen, and the obtained mixture was uniformly coated on a circular glass substrate, and the solvent was removed by distillation, and dried in air to obtain an organometallic framework material mixed matrix film.

[0067] The deuterium content of the low-deuterium water prepared in the embodiment was 25 ppm through analysis test.

[0068] Example 4

[0069] A vacuum low-temperature extraction process for low-deuterium water, the operation steps of which are as follows:

[0070] Step one: 3000 g of water was introduced into the reaction kettle according to the mass fraction, the sealing property of the reaction kettle was ensured to avoid water vapor leakage, the stirring system was started to ensure uniform distribution of water in the reaction kettle;

[0071] Step two: the vacuum pump was started to perform vacuum treatment on the reaction kettle, and the water temperature in the reaction kettle was gradually increased to the evaporation temperature through the heat conduction oil heating system after reaching the predetermined vacuum degree;

[0072] Step three: the water vapor generated in the reaction kettle was filtered through a membrane filter and then transported to a condenser through a high-purity pipeline, and the water vapor was rapidly condensed into liquid water, i.e., low-deuterium water, when it encountered a cooling surface in the condenser.

[0073] The stirring speed in step one is 60 rpm.

[0074] The vacuum degree of the reaction kettle in step two is 0.01 Pa.

[0075] The evaporation temperature of the reaction kettle in step two is 50℃.

[0076] The high-purity pipeline in step three is a high-purity PFA pipeline.

[0077] The membrane filter in step three is an organometallic framework material mixed matrix film, which comprises the following steps:

[0078] A: 42 g of 4-mercapto pyridine dicarboxylic acid and 46 g of zirconium chloride were mixed, and magnetic stirring was performed for 15 min, and then the mixture was placed in an autoclave and reacted at 100℃ for 22 h; after cooling, the mixture was soaked in 150 g of DMF for 40 min, and the solid product was collected by centrifugation; the solid product was washed with ultrapure water and ethanol three times, and then vacuum dried at 70℃ for 15 h to obtain a thiol MOF material;

[0079] B: 40 g of thiol MOF material powder was dispersed in 650 g of acetone, and ultrasonic treatment was performed for 40 min; 5 g of PVDF, 0.5 g of maleic anhydride polyether ester resin, 0.5 g of vinylpyridine-nickel, and 0.5 g of sodium ethoxide were added, and ultrasonic treatment was performed for 50 min; the acetone was blown dry with nitrogen, and the obtained mixture was uniformly coated on a circular glass substrate, and the solvent was removed by distillation, and dried in air to obtain an organic metal framework material mixed matrix film.

[0080] The deuterium content of the low-deuterium water prepared in this example was 10 ppm as tested by analysis.

[0081] Comparative Example 1

[0082] This comparative example is based on Example 1, except that no membrane filter was used in Step 3, and is not described again.

[0083] The deuterium content of the low-deuterium water prepared in this example was 265 ppm as tested by analysis.

[0084] Comparative Example 2

[0085] This comparative example is based on Example 1, except that no vinylpyridine-nickel was added during the preparation of the membrane filter in Step 3, and is not described again.

[0086] The deuterium content of the low-deuterium water prepared in this example was 185 ppm as tested by analysis.

[0087] From the above specific embodiments and test results, it can be seen that the membrane filter provided by the method significantly reduces the deuterium content of the low-deuterium water.

[0088] Of course, the above content is only a preferred embodiment of the present application, and cannot be considered as limiting the scope of the embodiments of the present application. The present application is also not limited to the above examples, and equivalent changes and improvements made by those skilled in the art within the scope of the present application should be attributed to the patent coverage of the present application.

Claims

1. A vacuum low-temperature extraction process for deuterium-rich water, comprising the following steps: Step 1: According to the mass fraction, add 1000-3000 parts of water to the reactor according to the mass fraction, ensure that the reactor is well sealed to prevent water vapor from leaking out, and turn on the stirring system to ensure that the water is evenly distributed in the reactor. Step 2: Start the vacuum pump to evacuate the reactor to the predetermined vacuum level, and then gradually raise the water temperature in the reactor to the evaporation temperature through the heat transfer oil heating system. Step 3: The water vapor generated in the reactor is filtered through a membrane filter and then transported to the condenser through a high-purity pipeline. In the condenser, the water vapor encounters the cooling surface and quickly condenses into liquid water, i.e., deuterium-free water. The membrane filter in step three uses a mixed matrix membrane with an organometallic framework material, and includes the following steps: A: By weight, 21-42 parts of 4-mercaptopyridine dicarboxylic acid and 23-46 parts of zirconium chloride are mixed and magnetically stirred for 5-15 minutes. Then, the mixture is placed in an autoclave and reacted at 90-100℃ for 10-22 hours. After cooling, the mixture is soaked in 100-150 parts of DMF for 20-40 minutes, and the solid product is collected by centrifugation. The mixture is washed three times each with ultrapure water and ethanol, and then vacuum dried at 60-70℃ for 10-15 hours to obtain the mercapto MOF material. B: Disperse 20-40 parts by weight of mercapto MOF material powder in 500-650 parts of acetone and sonicate for 20-40 min; then add 2-5 parts of PVDF, 0.02-0.5 parts of maleic anhydride polyether ester resin, 0.02-0.5 parts of vinylpyridine-nickel, and 0.02-0.5 parts of sodium ethoxide, and sonicate for 10-50 min; blow the acetone dry with nitrogen, and uniformly coat the resulting mixture on a circular glass substrate, remove the solvent by distillation, and dry in air to obtain a mixed matrix film of organometallic framework material.

2. The vacuum low-temperature extraction process for deuterium-rich water according to claim 1, characterized in that: The stirring speed in step one is 30-60 rpm.

3. The vacuum low-temperature extraction process for deuterium-rich water according to claim 1, characterized in that: In step two, the vacuum degree of the reactor is 0.01-1 Pa.

4. The vacuum low-temperature extraction process for deuterium-rich water according to claim 1, characterized in that: The evaporation temperature of the reactor in step two is 50-85℃.

5. The vacuum low-temperature extraction process for deuterium-rich water according to claim 1, characterized in that: The high-purity pipeline in step three is a high-purity PFA pipeline.