Preparation of an Ionic Porous Nitrogen-Rich Molecular Cage and Its Application in the Purification of Iodine-Containing Nuclear Medical Waste

Abstract

The present invention discloses the preparation of an ionic porous nitrogen-rich molecular cage and its application in the purification of iodine-containing nuclear medical waste, including: using ammonia or amine reagents as "bridges" and aldehyde or ketone reagents as reaction monomers, adopting the Schiff base reaction principle, and using a multi-dentate coordination method to cause an imine condensation reaction of substances through a one-pot method to generate a porous nitrogen-rich molecular cage; then adding a reducing agent to further reduce the porous nitrogen-rich molecular cage, and then combining with an alkyl halide and an organic solvent, and obtaining an ionic porous nitrogen-rich molecular cage through stirring and rotary evaporation. Beneficial effects: Selecting a porous organic cage material with an ionic nitrogen-rich ligand as an adsorbent, having stable physical and chemical properties; simple synthesis, high yield, and stable structure of the nitrogen-rich ligand, capable of adsorbing iodine in the gas phase and iodine in the aqueous phase, and being recyclable; having strong anti-ion interference ability, and being suitable for adsorbing iodine under the aqueous phase conditions of pH = 3-11; being able to be applied to the treatment of iodine in nuclear medical wastewater.

Description

Technical Field

[0001] The present invention belongs to the technical field of porous organic materials. More specifically, the present invention relates to the preparation of an ionic porous nitrogen-rich molecular cage and its application in the purification of iodine-containing nuclear medical waste. Background Art

[0002] With the explosive growth in the demand for medical isotopes, radioactive waste is increasing day by day. If discharged without treatment or improper treatment, the ecological environment will be radioactively polluted. 129 I and 131 A large amount of radioactive iodine, including - I, exists in the form of I2 or I3 in the water bodies of nuclear accident water and medical waste liquid water, posing a serious threat to people's physical health and personal safety. The liquid radioactive isotope waste generated by nuclear medicine has the characteristics of low toxicity, short half-life, and less waste liquid. At present, the treatment process of nuclear medical radioactive waste liquid in China mainly focuses on the storage decay method, and setting up a decay pool is the most commonly used means for treating nuclides with a shorter half-life. 131 The treatment methods for

[0003] As a class of frontier microporous materials, porous organic molecular cages represent an innovative progress in the field of microporous solid crystals. Each unit acts as a "molecular cage", internally rich in nano-scale cavities or channels, constituting a highly regular and adjustable microenvironment. Therefore, they perform excellently in the fields of molecular recognition and sensing, being able to specifically recognize and bind target molecules. In adsorption and separation science, these molecular cages can effectively capture specific gases, organic substances, and even ions, achieving efficient selective separation and purification. In addition, due to their additional advantages such as low framework density, dual porosity inside and outside the cage, and abundant iodine adsorption sites, porous organic molecular cages have the advantages of solution processability and simple operation in adsorption. Summary of the Invention

[0004] An object of the present invention is to solve at least the above problems and / or defects and provide at least the advantages described hereinafter.

[0005] To achieve these objects and other advantages according to the present invention, there is provided an ionic porous nitrogen-rich molecular cage having the following structural formula:

[0006]

[0007] where n = 0 - 15, X represents I or Br, and R represents one or a combination of CH and N.

[0008] A preparation method of an ionic porous nitrogen-rich molecular cage: Using ammonia or amine reagents as "bridges" and aldehyde or ketone reagents as reaction monomers, adopting the Schiff base reaction principle, and using a multi-dentate coordination method to cause an imine condensation reaction of substances through a one-pot method to generate a porous nitrogen-rich molecular cage. Further reducing the molecular cage, and then combining with an alkyl halide and an organic solvent, and obtaining the ionic porous nitrogen-rich molecular cage through stirring and rotary evaporation.

[0009] Preferably, the preparation method is specifically as follows:

[0010] S1. Dissolve an amine compound in an organic solvent to prepare solution a, dissolve an aldehyde compound in an organic solvent to prepare solution b, and then add solution a to solution b and stir or ultrasonically mix them; let it stand and react at a certain temperature for a certain time, and filter, wash, and dry the obtained product to obtain a porous nitrogen-rich molecular cage (CC6) adsorption material;

[0011] S2. One-step reduce the porous nitrogen-rich molecular cage material powder in step S1 with a reducing agent;

[0012] S3. Dissolve the reduced porous nitrogen-rich molecular cage powder in step S2 in an organic solvent, then drop an alkyl halide into the bottle, heat it in an oil bath for a period of time, and then perform rotary evaporation to obtain an ionic porous nitrogen-rich molecular cage (XCC6) adsorption material.

[0013] Preferably, in S1, the amine compound includes one or more of ethylenediamine, triethylenetetramine, pentanediamine, triamine, and cyclohexanediamine, and the aldehyde compound includes one or more of benzene-1,3,5-tricarbaldehyde, 1,3,5-tris(4-formylphenyl)benzene, terephthalaldehyde, and isophthalaldehyde.

[0014] Preferably, in S1 and S2, the organic solvent includes one or more of acetone, acetonitrile, dichloromethane, methanol, ethanol, toluene, and dimethyl sulfoxide, and the reducing agent includes one or more of ascorbic acid, lithium aluminum hydride, sodium borohydride, and zinc borohydride.

[0015] Preferably, in S1, the mass concentration of the amine compound in solution a is 0 - 1 g / L, the mass concentration of the aldehyde compound in solution b is 1 - 5 g / L, the volume of the organic solvent is 30 - 80 mL, and the volume ratio of solution a to solution b is 1 - 2:1 - 2; the reaction time is 48 - 72 h.

[0016] Preferably, in S3, the mass of the porous nitrogen-rich molecular cage adsorption material powder is 10-100 mg, the volume of the organic solvent is 5-30 mL, and the alkyl halide is added after dissolution, and the molar ratio of the two is: porous nitrogen-rich molecular cage powder: alkyl halide = 1:0.1-100, the oil bath reaction temperature is 20°C-50°C, the reaction time is 2-8h, the rotary evaporation temperature is 40-80°C, and the reaction time is 4-12h.

[0017] Preferably, in S1 and S3, a catalyst can be used during the reaction, and the catalyst is trifluoroacetic acid or acetic acid, with an analytically pure concentration and a volume of 0-2 μL.

[0018] Preferably, in S3, the alkyl halide is one or more of methyl iodide, ethyl bromide, pentane bromide, octane bromide, dodecane bromide, tetradecane bromide, and hexadecane bromide.

[0019] The invention discloses an application of an ionic porous nitrogen-rich molecular cage in the purification of iodine-containing nuclear medical waste, comprising the adsorption of iodine ions and volatile iodine in nuclear medical wastewater, wherein the adsorption temperature of volatile iodine is 25-100°C, the concentration range of volatile iodine is 1-1000 mg / L, the time is 1-10 hours, and the concentration range of iodine ions in water is 1-500 mg / L, the time is 28-48 hours.

[0020] The present invention has at least the following beneficial effects:

[0021] (1) The present invention selects a porous organic cage material with ionic nitrogen-rich ligands as an adsorbent, and the porous organic cage has stable physical and chemical properties;

[0022] (2) The porous organic cage material designed by the present invention has the advantages of simple synthesis, high yield, and stable structure of nitrogen-rich ligands. It can adsorb iodine in the gas phase and iodine in the water phase and can be recycled;

[0023] (3) The device used in the present invention does not require the addition of other chemicals to operate, does not introduce new impurities, and rarely generates subsequent waste;

[0024] (4) The material of the present invention has strong anti-ion interference ability and is suitable for adsorbing iodine under pH=3-11 aqueous phase conditions;

[0025] (5) The present invention has a wide range of applications and can treat iodine in nuclear medical waste liquid and nuclear waste gas.

[0026] Other advantages, objectives and features of the present invention will be embodied in part through the following description, and in part will be understood by those skilled in the art through study and practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a schematic diagram of the structure of a nuclear medical wastewater treatment device in Application Example 1 of the present invention;

[0028] Figure 2 Normal light micrograph of the ionic porous nitrogen-rich molecular cage prepared in Example 1 of the present invention;

[0029] Figure 3 Polarized light micrograph of the ionic porous nitrogen-rich molecular cage prepared in Example 1 of the present invention;

[0030] Figure 4 Removal rate graph of iodine solution adsorbed by the ionic porous nitrogen-rich molecular cage in Application Example 3 of the present invention;

[0031] Figure 5 Iodine vapor adsorption graph of CC6 and XCC6 in Application Example 2 of the present invention;

[0032] Figure 6 Adsorption capacity graph of CC6 and XCC6 in Application Example 1 of the present invention;

[0033] Figure 7 Adsorption capacity graph of the ionic porous nitrogen-rich molecular cage at different pH values in Application Example 4 of the present invention;

[0034] Figure 8 Structure diagram of the XCC6 adsorption material in Example 1 of the present invention;

[0035] Figure 9 Structure diagram of the XCC6 adsorption material in Example 2 of the present invention;

[0036] Figure 10 Structure diagram of the XCC6 adsorption material in Example 3 of the present invention;

[0037] Figure 11 Structure diagram of the XCC6 adsorption material in Example 4 of the present invention;

[0038] Figure 12 Structure diagram of the XCC6 adsorption material in Example 5 of the present invention. Detailed implementation manners

[0039] The present invention will be further described in detail below with reference to the accompanying drawings, so that those skilled in the art can implement it according to the description in the specification.

[0040] Example 1

[0041] A preparation method of an ionic porous nitrogen-rich molecular cage, comprising:

[0042] S1. Dissolve 0.192 mmol of pentanediamine in 20 mL of methanol and stir evenly to obtain solution a with a concentration of 1 g / L. Dissolve 0.128 mmol of 1,3,5-tris(4-formylphenyl)benzene in 20 mL of methanol and stir evenly to obtain solution b with a concentration of 2.5 g / L. Subsequently, add solution a to solution b, let the sample bottle stand for reaction for 72 h at a reaction temperature of 25 °C. The obtained product is filtered, washed, and dried to obtain the product porous nitrogen-rich molecular cage (CC6) adsorbent material;

[0043] S2. Reduce the porous nitrogen-rich molecular cage material powder in step S1 with sodium borohydride reductant in one step. The method is as follows: Dissolve 0.5 g of CC6 in 25 mL of a mixed solvent of dichloromethane and methanol (v / v = 1 / 1), add 0.1 g of sodium borohydride (NaBH4) under vigorous stirring, and the mixed solution reacts at room temperature for 20 h. Subsequently, add 1 mL of deionized water as the solvent and continue to react at room temperature for 9 h. The obtained solid product is filtered, washed, and dried to obtain the reduced CC6 adsorbent material;

[0044] S3. Dissolve 100 mg of the reduced CC6 adsorbent material powder in 25 mL of toluene, and then drop dodecyl bromide with a molar ratio of CC6:dodecyl bromide = 1:12 into the bottle. Heat and react at 50 °C in an oil bath for 2 h. After complete dissolution, crystallize by rotary evaporation at 60 °C for 4 h to obtain the ionic porous nitrogen-rich molecular cage (XCC6) adsorbent material, and its structure is as Figure 8 shown.

[0045] Figure 2 is the normal light micrograph of the ionic porous nitrogen-rich molecular cage prepared in Example 1 of the present invention; Figure 3 is the polarized light micrograph of the ionic porous nitrogen-rich molecular cage prepared in Example 1 of the present invention; It can be seen from Figures 2 to 3 that the obtained ionic porous nitrogen-rich molecular cage (XCC6) has a bright birefringence phenomenon, indicating good crystallinity.

[0046] Example 2

[0047] A preparation method of an ionic porous nitrogen-rich molecular cage, comprising:

[0048] S1. Dissolve 0.192 mmol of diethylenetriamine in 20 mL of methanol and stir evenly to obtain solution a with a concentration of 1 g / L. Dissolve 0.128 mmol of 1,3,5-tris(4-formylphenyl)benzene in 20 mL of methanol and stir evenly to obtain solution b with a concentration of 2.5 g / L. Subsequently, add solution a to solution b, let the sample bottle stand for reaction for 72 h at a reaction temperature of 25 °C. The obtained product is filtered, washed, and dried to obtain the product CC6 adsorbent material;

[0049] S2. One-step reduction of the CC6 adsorbent material powder in step S1 with sodium borohydride as the reducing agent. The method is as follows: Dissolve 0.5 g of CC6 in 25 mL of a dichloromethane and methanol mixed solvent (v / v = 1 / 1), add 0.1 g of sodium borohydride (NaBH4) under vigorous stirring, and let the mixed solution react at room temperature for 20 h. Subsequently, add 1 mL of deionized water as the solvent and continue to react at room temperature for 9 h. The obtained solid product can be obtained as the reduced CC6 adsorbent material after filtration, washing, and drying.

[0050] S3. Dissolve 100 mg of the reduced CC6 adsorbent material powder in 20 mL of toluene, then drop 0.096 g of iodomethane with a molar ratio of CC6:chloropentane = 1:9 into the bottle. After heating and reacting in an oil bath at 35 °C for 3 h and waiting for complete dissolution, perform rotary evaporation crystallization at 60 °C for 4 h to obtain the XCC6 adsorbent material, whose structure is as Figure 9 shown.

[0051] Example 3

[0052] A preparation method of an ionic porous nitrogen-rich molecular cage, comprising:

[0053] S1. Dissolve 0.192 mmol of 2,2-diamino-N-methyldiethylamine in 20 mL of methanol and stir evenly to obtain solution a with a concentration of 1 g / L. Dissolve 0.128 mmol of 1,3,5-tris(4-formylphenyl)benzene in 20 mL of methanol and stir evenly to obtain solution b with a concentration of 2.5 g / L. Subsequently, add solution a to solution b, let the sample bottle stand and react for 72 h at a reaction temperature of 25 °C. The obtained product can be obtained as the product CC6 adsorbent material after filtration, washing, and drying.

[0054] S2. One-step reduction of the CC6 adsorbent material powder in step S1 with sodium borohydride as the reducing agent. The method is as follows: Dissolve 0.5 g of CC6 in 25 mL of a dichloromethane and methanol mixed solvent (v / v = 1 / 1), add 0.1 g of sodium borohydride (NaBH4) under vigorous stirring, and let the mixed solution react at room temperature for 20 h. Subsequently, add 1 mL of deionized water as the solvent and continue to react at room temperature for 9 h. The obtained solid product can be obtained as the reduced CC6 adsorbent material after filtration, washing, and drying.

[0055] S3. Dissolve 100 mg of the reduced CC6 adsorbent material powder in 20 mL of toluene, then drop 0.1641 g of bromoethane with a molar ratio of CC6:bromoethane = 1:6 into the bottle. After heating and reacting in an oil bath at 35 °C for 3 h and waiting for complete dissolution, perform rotary evaporation crystallization at 60 °C for 4 h to obtain the XCC6 adsorbent material, whose structure is as Figure 10 shown.

[0056] Example 4

[0057] A preparation method of an ionic porous nitrogen-rich molecular cage, comprising:

[0058] S1. Dissolve 0.192 mmol of triethylenetetramine in 20 mL of methanol and stir evenly to obtain solution a with a concentration of 1 g / L. Dissolve 0.128 mmol of 1,3,5-tris(4-formylphenyl)benzene in 20 mL of methanol and stir evenly to obtain solution b with a concentration of 2.5 g / L. Subsequently, add solution a to solution b, let the sample bottle stand for reaction for 72 h at a reaction temperature of 25 °C. The obtained product is filtered, washed, and dried to obtain the CC6 adsorbent material;

[0059] S2. One-step reduction of the CC6 adsorbent material powder in step S1 with sodium borohydride as a reducing agent; the method is as follows: dissolve 0.5 g of CC6 in 25 mL of a dichloromethane and methanol mixed solvent (v / v = 1 / 1), add 0.1 g of sodium borohydride (NaBH4) under vigorous stirring, and let the mixed solution react at room temperature for 20 h. Subsequently, add 1 mL of deionized water as a solvent and continue to react at room temperature for 9 h. The obtained solid product is filtered, washed, and dried to obtain the reduced CC6 adsorbent material;

[0060] S3. Dissolve 100 mg of the reduced CC6 adsorbent material powder in 20 mL of toluene, then drop 0.183 g of bromopentane with a molar ratio of CC6:bromopentane = 1:12 into the bottle, heat and react in an oil bath at 35 °C for 3 h, wait until it is completely dissolved, and crystallize by rotary evaporation at 60 °C for 4 h to obtain the XCC6 adsorbent material, whose structure is as Figure 11 shown.

[0061] Example 5

[0062] A preparation method of an ionic porous nitrogen-rich molecular cage, comprising:

[0063] S1. Dissolve 0.192 mmol of 1,8-octanediamine in 20 mL of methanol and stir evenly to obtain solution a with a concentration of 1 g / L. Dissolve 0.128 mmol of 1,3,5-tris(4-formylphenyl)benzene in 20 mL of methanol and stir evenly to obtain solution b with a concentration of 2.5 g / L. Subsequently, add solution a to solution b, let the sample bottle stand for reaction for 72 h at a reaction temperature of 25 °C. The obtained product is filtered, washed, and dried to obtain the CC6 adsorbent material;

[0064] S2. One-step reduction of the CC6 adsorbent material powder in step S1 with sodium borohydride as the reducing agent. The method is as follows: Dissolve 0.5 g of CC6 in 25 mL of a dichloromethane and methanol mixed solvent (v / v = 1 / 1), add 0.1 g of sodium borohydride (NaBH4) under vigorous stirring, and let the mixed solution react at room temperature for 20 h. Subsequently, add 1 mL of deionized water as the solvent and continue to react at room temperature for 9 h. The obtained solid product is filtered, washed, and dried to obtain the reduced CC6 adsorbent material;

[0065] S3. Dissolve 100 mg of the reduced CC6 adsorbent material powder in 20 mL of toluene, then drop 0.1679 g of bromotetradecane with a molar ratio of CC6:bromotetradecane = 1:6 into the flask. After heating and reacting in an oil bath at 35 °C for 3 h and waiting for complete dissolution, crystallize by rotary evaporation at 60 °C for 4 h to obtain the XCC6 adsorbent material, whose structure is as Figure 12 shown.

[0066] Example 6

[0067] A preparation method of an ionic porous nitrogen-rich molecular cage, comprising:

[0068] S1. Dissolve 0.192 mmol of pentanediamine in 20 mL of methanol and stir evenly to obtain solution a with a concentration of 1 g / L. Dissolve 0.128 mmol of 1,3,5-tris(4-formylphenyl)benzene in 20 mL of methanol and stir evenly to obtain solution b with a concentration of 2.5 g / L. Add 0.1 μL of acetic acid dropwise to solution b, and then add solution a to solution b. Let the sample bottle stand and react for 24 h at a reaction temperature of 25 °C. The obtained product is filtered, washed, and dried to obtain the product CC6 adsorbent material;

[0069] The remaining steps are the same as those in Example 1.

[0070] Comparative Example 1

[0071] A preparation method of a nitrogen-rich molecular cage, comprising:

[0072] S1. Dissolve 0.192 mmol of pentanediamine in 20 mL of methanol and stir evenly to obtain solution a with a concentration of 1 g / L. Dissolve 0.128 mmol of 1,3,5-tris(4-formylphenyl)benzene in 20 mL of methanol and stir evenly to obtain solution b with a concentration of 2.5 g / L. Subsequently, add solution a to solution b. Let the sample bottle stand and react for 72 h at a reaction temperature of 25 °C. The obtained product is filtered, washed, and dried to obtain the product porous nitrogen-rich molecular cage (CC6) adsorbent material.

[0073] Application Example 1

[0074] Application of an ionic porous nitrogen-rich molecular cage adsorbent material in adsorbing iodine solution, including:

[0075] Put 200 mg of the dried XCC6 adsorbent material prepared in Example 1 and 200 mg of the CC6 adsorbent material prepared in Comparative Example 1 into glass chromatography columns respectively. Use absolute ethanol to completely pass through the glass chromatography columns filled with the adsorbent material until the adsorbent material is completely wet. Adjust the flow rate of the peristaltic pump to 5 mL / min, and introduce iodine-containing nuclear medical wastewater (concentration 20 mg / L) into a glass chromatography column with an inner diameter of 5 cm and an effective height of 20 cm, and collect the wastewater to complete the deep purification of iodine-containing nuclear medical wastewater. The device diagram is as Figure 1 shown. The iodine solution adsorption capacities of XCC6 and CC6 are as Figure 6 shown. It can be seen from Figure 6 that the iodine adsorption capacity of XCC6 reaches 428.6 mg / g, which is significantly higher than the adsorption amount of 228.6 mg / g of CC6.

[0076] Application Example 2

[0077] Application of an ionic porous nitrogen-rich molecular cage adsorbent material in adsorbing iodine vapor, including:

[0078] Put 10 mg of the XCC6 adsorbent material prepared in Example 1 and 10 mg of the CC6 adsorbent material prepared in Comparative Example 1 into weighing bottles respectively, then place the weighing bottles in wide-mouth bottles, weigh, seal, and place them in an oven at different temperatures (25 °C, 50 °C, 75 °C) for heating. The adsorption performance of the materials for iodine vapor is calculated by the gravimetric method. The adsorption capacities of XCC6 and CC6 at 75 °C are as Figure 5 shown. The adsorption capacity of XCC6 reaches 6.74 g / g, and the adsorption capacity of CC6 reaches 6.0 g / g. It can be seen that the adsorption performance of XCC6 for iodine vapor is also higher than that of CC6.

[0079] Application Example 3

[0080] Application of an ionic porous nitrogen-rich molecular cage adsorbent material in purifying iodine-containing wastewater, including:

[0081] Take three groups of 20 mg of washed and dried XCC6 adsorbent materials, and add 25 mL of I - potassium iodide iodine aqueous solutions with concentrations of 100 mg / L, 150 mg / L, and 200 mg / L respectively. The pH is the pH of pure water. After mixing the XCC6 adsorbent material and the solution evenly, shake it at a speed of 270 r / min on a constant temperature shaker for 48 hours. The reaction temperature is 25 °C. Separate by solid-liquid separation method, take the supernatant and measure it by ultraviolet spectrophotometry at a wavelength of 227 nm. The obtained results are the I - concentrations at different time gradients. Taking 200 mg / L as an example, the adsorption efficiency is asFigure 4 As shown, the removal rate reaches 99% within 24 hours.

[0082] Application Example 4

[0083] An application of an ionic porous nitrogen-rich molecular cage adsorption material for purifying iodine-containing wastewater, including:

[0084] Take 20 mg of the washed and dried XCC6 adsorption material, and add 25 mL of potassium iodide iodine aqueous solution with an I- concentration of 500 mg / L respectively. According to pH = 3 - 11, after mixing the XCC6 adsorption material and the solution evenly, shake it on a constant temperature shaker at a speed of 270 r / min for 24 hours, the reaction temperature is 25 °C, separate by solid-liquid separation method, take the supernatant and measure it by ultraviolet spectrophotometry at a wavelength of 227 nm. The adsorption capacity is as Figure 7 As shown, it can be seen that there is a good adsorption effect within the range of pH = 3 - 11, and the adsorption effect has no obvious change.

[0085] Application Example 5

[0086] A cyclic application of an ionic porous nitrogen-rich molecular cage adsorption material, including:

[0087] Perform high-temperature desorption at 150 °C on the XCC6 adsorption material after adsorbing iodine vapor in Application Example 2. The solid powder obtained after desorption is dried in an oven at 100 °C for 12 h, and then repeat the adsorption in Application Example 2;

[0088] Soak the XCC6 adsorption material that adsorbed iodine waste liquid in Application Example 1 with isopropanol or ethanol for multiple times, wash it with ultrapure water for multiple times. The solid powder obtained after washing is dried in an oven at 100 °C for 12 h, and then repeat the adsorption in Application Example 1.

[0089] The test shows that the cyclic rates of iodine vapor adsorption and iodine waste liquid adsorption of the XCC6 adsorption material both reach 70%.

[0090] Although the embodiments of the present invention have been disclosed as above, it is not limited to only the applications listed in the specification and embodiments. It can be fully applied to various fields suitable for the present invention. For those familiar with the field, additional modifications can be easily achieved. Therefore, without departing from the general concept defined by the claims and the equivalent scope, the present invention is not limited to specific details and the examples shown and described herein.

Claims

1. A method for preparing an ionic porous nitrogen-rich molecular cage, characterized in that: include: S1. Dissolving an amine compound in an organic solvent to prepare a solution a, dissolving an aldehyde compound in an organic solvent to prepare a solution b, then adding solution a to solution b and stirring or ultrasonically mixing; standing at a certain temperature for a certain period of time, using the Schiff base reaction principle to cause an imine condensation reaction, filtering, washing, and drying the obtained product to obtain a porous nitrogen-rich molecular cage adsorption material; S2, reducing the porous nitrogen-rich molecular cage material powder in step S1 with a reducing agent in one step; S3, dissolving the porous nitrogen-rich molecular cage powder reduced in step S2 in an organic solvent, then dropping a halide into the bottle, heating it in an oil bath for a period of time, and then performing rotary evaporation to obtain an ionic porous nitrogen-rich molecular cage adsorption material; Among them, the ionic porous nitrogen-rich molecular cage has the following structural formula: Where n = 0-15, X represents I, Br, and R represents one or a combination of CH, N; In S1, the amine compound includes one or more of ethylenediamine, triethylenetetramine, pentamethylenediamine, triamine, and cyclohexanediamine, and the aldehyde compound includes one or more of trimesic acid, 1,3,5-tris(4-formylphenyl)benzene, terephthalaldehyde, and isophthalaldehyde; In S3, the alkyl halide is one or more of methyl iodide, ethyl bromide, pentane bromide, octane bromide, dodecane bromide, tetradecane bromide, and hexadecane bromide.

2. The method for preparing the ionic porous nitrogen-rich molecular cage according to claim 1, characterized in that: In S1 and S2, the organic solvent includes one or more of acetone, acetonitrile, dichloromethane, methanol, ethanol, toluene, and dimethyl sulfoxide, and the reducing agent includes one or more of ascorbic acid, lithium aluminum oxide, sodium borohydride, and zinc borohydride.

3. The method for preparing the ionic porous nitrogen-rich molecular cage according to claim 1, characterized in that: In S1, the mass concentration of the amine compound in solution a is 0-1 g / L, the mass concentration of the aldehyde compound in solution b is 1-5 g / L, the volume of the organic solvent is 30-80 mL, and the volume ratio of solution a to solution b is 1-2:1-2; the reaction time is 48-72 h.

4. The method for preparing the ionic porous nitrogen-rich molecular cage according to claim 1, characterized in that: In S3, the mass of the porous nitrogen-rich molecular cage adsorption material powder is 10-100 mg, the volume of the organic solvent is 5-30 mL, and the alkyl halide is added after dissolution, and the molar ratio of the two is: porous nitrogen-rich molecular cage powder: alkyl halide = 1:0.1-100, the oil bath reaction temperature is 20°C-50°C, the reaction time is 2-8h, the rotary evaporation temperature is 40-80°C, and the reaction time is 4-12h.

5. The method for preparing the ionic porous nitrogen-rich molecular cage according to claim 1, characterized in that: In S1 and S3, a catalyst may be used during the reaction. The catalyst is trifluoroacetic acid or acetic acid, the concentration is analytical grade, and the volume is 0-2 ul.

6. An application of the ionic porous nitrogen-rich molecular cage as claimed in claims 1 to 5 in the purification of iodine-containing medical waste, characterized in that: It includes the adsorption of iodine ions and volatile iodine in nuclear medical wastewater. The adsorption temperature of volatile iodine is 25-100°C, the concentration range of volatile iodine is 1-1000 mg / L, the time is 1-10h, and the concentration range of iodine ions in the adsorption water is 1-500 mg / L, and the time is 28-48h.

Images