Adsorption resin as well as preparation method and application thereof

Abstract

The invention provides adsorption resin as well as a preparation method and application thereof, and belongs to the technical field of nuclear chemical engineering. According to the preparation method, the porous resin matrix and the NTA amide (C8) extraction agent are prepared firstly, then the NTA amide (C8) extraction agent is filled into the pore channels of the porous resin matrix through vacuum infusion, the NTA amide (C8) extraction agent is prevented from falling off in the subsequent application process under the high-acidity condition, the stability and adsorbability of the NTA amide (C8) resin under the high-acidity condition are improved, and the service life of the NTA amide (C8) resin is prolonged. Meanwhile, the variety of the porous resin matrix is controlled, so that the NTA amide (C8) resin has better inertness, the stability and adsorbability of the NTA amide (C8) resin under a high-acidity condition are further improved, and the NTA amide (C8) resin has excellent selective adsorption on Th (IV).

Description

Technical Field

[0001] The invention belongs to the technical field of nuclear chemical industry, and particularly relates to an adsorption resin and a preparation method and application thereof. Background Art

[0002] Compared to conventional nuclear reactors, thorium-based fuel reactors are considered an important option for future nuclear energy development due to their multiple advantages and characteristics. Separating thorium from spent nuclear fuel not only allows for the recovery of some unused thorium fuel but also reduces the long-term radioactive hazards of nuclear waste, lowering potential risks to the environment and organisms. However, high-level radioactive wastes (HLLWs) are often complex mixtures under highly acidic and irradiated conditions. Therefore, the selective separation and recovery of Th(IV) from concentrated HNO3 solutions remains a challenging task. Common methods for the separation and recovery of Th(IV) include solvent extraction, solid-phase extraction, and ion exchange. Solvent extraction selectively extracts thorium from the solution into the organic phase by forming a complex with thorium ions in the aqueous phase using a suitable organic solvent. However, solvent extraction generates large amounts of organic waste, and the extraction, stripping, and solution washing processes increase operational complexity. Furthermore, the treatment and regeneration of the spent solvents can incur additional regeneration and disposal costs. Ion exchange methods, based on the functionality of ion exchange resins, utilize the active sites on the resin to exchange with thorium ions in solution, effectively separating thorium from other metal ions, thereby achieving the separation and recovery of thorium ions. They perform particularly well in complex matrices, offering advantages such as high selectivity and strong adaptability. However, ion exchange rates are slow, adsorption capacity is limited, and resin stability issues can occur under strong acidic conditions, affecting separation efficiency, thus limiting their use in Th(IV) separation. Solid-phase extraction, as an efficient separation technique, combines the high selectivity of solvent extraction with the simplicity and rapidity of column chromatography and has shown promising application potential in the separation and extraction of thorium. However, the adsorption performance of existing solid-phase extraction columns is significantly reduced under highly acidic conditions. In recent years, amide ligands have attracted widespread attention due to their excellent complexing properties. Among them, the nitrilotriacetamide ligand (NTA amide), which has three amide moieties attached to a tripodal nitrogen atom, and a ligand structure with hard (O) and soft (N) donor atoms, provides efficient extraction performance, but its selective adsorption of Th(IV) is poor. Therefore, how to make the resin still have excellent adsorption performance under highly acidic conditions and have excellent selective adsorption for Th(IV) has become a difficult problem in this field. Summary of the Invention

[0003] The purpose of the present invention is to provide an adsorption resin and its preparation method and application. The adsorption resin prepared by the preparation method provided by the present invention still has excellent adsorption performance under highly acidic conditions and has excellent selective adsorption for Th(IV).

[0004] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions: The present invention provides a method for preparing an adsorption resin, comprising the following steps: (1) gelatin, calcium chloride and water are mixed to obtain an aqueous phase solution; divinylbenzene, styrene, kerosene and toluene are mixed to obtain an oil phase; the aqueous phase solution, the oil phase and an initiator are mixed to carry out a suspension polymerization reaction to obtain a porous resin matrix; (2) mixing oxalyl chloride, nitrilotriacetic acid, N,N-dimethylformamide and dichloromethane, and performing an acyl chlorination reaction to obtain an intermediate; mixing the intermediate with dioctylamine and dichloromethane, and performing an amidation reaction to obtain an extractant; (3) mixing the porous resin matrix obtained in step (1), the extractant obtained in step (2), an isodecyl alcohol-n-dodecane mixed solution and an alcohol solvent, and sequentially performing oscillation and vacuum infusion to obtain an adsorption resin; the mass ratio of the extractant to the porous resin matrix is 1:(1-1.5); There is no order in which steps (1) and (2) are performed.

[0005] Preferably, in step (1), the mass ratio of gelatin, calcium chloride and water is (3-4): (0.3-0.4): 300.

[0006] Preferably, in step (1), the mass ratio of divinylbenzene, styrene, kerosene, toluene and initiator is (4-5): (1.2-1.5): (5-7): 3: 0.12.

[0007] Preferably, the suspension polymerization reaction temperature in step (1) is 85-95° C., and the suspension polymerization reaction time is 9-11 h.

[0008] Preferably, the temperature of the chlorination reaction in step (2) is 35-45° C., and the time of the chlorination reaction is 6-8 h.

[0009] Preferably, the temperature of the amidation reaction in step (2) is ≤5°C, and the amidation reaction time is 11-13 hours.

[0010] Preferably, the volume ratio of isodecyl alcohol to n-dodecane in the isodecyl alcohol-n-dodecane mixed solution in step (3) is 1:(3.5-4.5).

[0011] Preferably, in step (3), the mass ratio of the extractant to the isodecyl alcohol-n-dodecane mixed solution is 1:(0.8-1.0).

[0012] The present invention also provides an adsorption resin prepared by the preparation method described in the above technical solution, comprising a porous resin matrix and an extractant loaded on the surface and inside the pores of the porous resin matrix.

[0013] The present invention also provides the use of the adsorption resin described in the above technical solution in adsorbing thorium ions.

[0014] The present invention provides a preparation method of an adsorption resin, comprising the following steps: (1) mixing gelatin, calcium chloride and water to obtain an aqueous phase solution; mixing divinylbenzene, styrene, kerosene and toluene to obtain an oil phase; mixing the aqueous phase solution, the oil phase and an initiator, and performing a suspension polymerization reaction to obtain a porous resin matrix; (2) mixing oxalyl chloride, nitrilotriacetic acid, N,N-dimethylformamide and dichloromethane, and performing an acyl chloride reaction to obtain an intermediate; mixing the intermediate with di-n-octylamine and dichloromethane, and performing an amidation reaction to obtain an extractant; (3) mixing the porous resin matrix obtained in step (1), the extractant obtained in step (2), an isodecyl alcohol-n-dodecane mixed solution and an alcohol solvent, and performing shaking and vacuum perfusion in sequence to obtain an adsorption resin; the mass ratio of the extractant to the porous resin matrix is 1:(1-1.5); and steps (1) and (2) are not performed in any order. The present invention first prepares a porous resin matrix and an extractant (NTA amide (C8) extractant). The NTA amide (C8) extractant is then impregnated into the pores of the porous resin matrix using vacuum infusion. This prevents the NTA amide (C8) extractant from falling out during subsequent use under highly acidic conditions, thereby improving the stability and adsorption of the adsorption resin (NTA amide (C8) resin) under highly acidic conditions. Furthermore, the type of porous resin matrix is controlled, resulting in good inertness, further improving the stability and adsorption of the NTA amide (C8) resin under highly acidic conditions. Furthermore, the NTA amide (C8) resin exhibits excellent selective adsorption for Th(IV). Results from the examples show that the NTA amide (C8) resin prepared by the preparation method provided by the present invention exhibits excellent adsorption capacity and selective adsorption for Th(IV) under 7 mol / L HNO3. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 : is the Fourier transform infrared spectrum of the porous resin matrix and NTA amide (C8) resin prepared in Example 1; Figure 2 is a SEM image of the porous resin matrix prepared in Example 1; Figure 2 In the figure, a is a SEM image of the porous resin matrix with a magnification of 70 times, and b is a SEM image of the porous resin matrix with a magnification of 500 times; Figure 3 is a SEM image of the NTA amide (C8) resin prepared in Example 1; Figure 3 In the figure, a is a SEM image of NTA amide (C8) resin at a magnification of 80 times, and b is a SEM image of NTA amide (C8) resin at a magnification of 500 times; Figure 4 This is a nitrogen adsorption-desorption curve of the porous resin matrix prepared in Example 1; Figure 5 is a pore size distribution diagram of the porous resin matrix prepared in Example 1; Figure 6 Adsorption rate and distribution coefficient of Th (IV) by NTA amide (C8) resin prepared in Example 1 at different nitric acid concentrations K d value; Figure 7 The adsorption capacity of NTA amide (C8) resin prepared in Example 1 for Th (IV) at different nitric acid concentrations; Figure 8 The adsorption capacity and adsorption isotherm fitting curve of NTA amide (C8) resin prepared in Example 1 for Th (IV) at different initial Th (IV) concentrations; Figure 9 The adsorption rate of Th (IV) by the NTA amide (C8) resin prepared in Example 1 at different adsorption times; Figure 10 The distribution of different interfering ions in the NTA amide (C8) resin prepared in Example 1; Figure 11 is the adsorption rate of Th (IV) by the NTA amide (C8) resin prepared in Example 1 in the presence of different interfering ions; Figure 12 The dynamic column performance of the NTA amide (C8) resin prepared in Example 1. DETAILED DESCRIPTION

[0016] The present invention provides a method for preparing an adsorption resin, comprising the following steps: (1) gelatin, calcium chloride and water are mixed to obtain an aqueous phase solution; divinylbenzene, styrene, kerosene and toluene are mixed to obtain an oil phase; the aqueous phase solution, the oil phase and an initiator are mixed to carry out a suspension polymerization reaction to obtain a porous resin matrix; (2) mixing oxalyl chloride, nitrilotriacetic acid, N,N-dimethylformamide and dichloromethane, and performing an acyl chlorination reaction to obtain an intermediate; mixing the intermediate with dioctylamine and dichloromethane, and performing an amidation reaction to obtain an extractant; (3) mixing the porous resin matrix obtained in step (1), the extractant obtained in step (2), an isodecyl alcohol-n-dodecane mixed solution and an alcohol solvent, and sequentially performing oscillation and vacuum infusion to obtain an adsorption resin; the mass ratio of the extractant to the porous resin matrix is 1:(1-1.5); There is no order in which steps (1) and (2) are performed.

[0017] Unless otherwise specified, the present invention has no particular limitation on the sources of the raw materials, and commercially available products known to those skilled in the art may be used.

[0018] The invention mixes gelatin, calcium chloride and water to obtain an aqueous phase solution.

[0019] In the present invention, the mass ratio of gelatin, calcium chloride, and water is preferably (3-4):(0.3-0.4):300. In one embodiment, the mass ratio of gelatin, calcium chloride, and water can be specifically 3:0.3:300, 3.2:0.32:300, 3.4:0.34:300, 3.6:0.36:300, 3.8:0.38:300, or 4:0.4:300. In the present invention, gelatin and calcium chloride serve as dispersion media. By controlling the mass ratio of gelatin, calcium chloride, and water within the above range, the gelatin and calcium chloride can be fully dissolved.

[0020] In the present invention, the temperature for mixing the gelatin, calcium chloride, and water is preferably 65-75°C, more preferably 70°C; the mixing of the gelatin, calcium chloride, and water is preferably performed under stirring; and the stirring speed is preferably 250-350 rpm, more preferably 300 rpm. The present invention does not specifically limit the mixing time, as long as the gelatin and calcium chloride are completely dissolved.

[0021] The present invention mixes divinylbenzene, styrene, kerosene and toluene to obtain an oil phase.

[0022] In the present invention, divinylbenzene and styrene are used as polymerization monomers. The present invention uses the above polymerization monomers to make the prepared porous resin matrix have better inertness, which can further improve the stability and adsorption of NTA amide (C8) resin under highly acidic conditions.

[0023] In the present invention, the kerosene is used as a diluent.

[0024] In the present invention, the toluene is a porogen.

[0025] In the present invention, the divinylbenzene, styrene, kerosene and toluene are preferably mixed by mixing divinylbenzene and styrene, and then adding kerosene and toluene.

[0026] After obtaining the aqueous phase solution and the oil phase, the present invention mixes the aqueous phase solution, the oil phase and an initiator to carry out a suspension polymerization reaction to obtain a porous resin matrix.

[0027] In the present invention, the initiator is preferably benzoyl peroxide or azobisisobutyronitrile.

[0028] In the present invention, the mass ratio of divinylbenzene, styrene, kerosene, toluene, and initiator is preferably (4-5):(1.2-1.5):(5-7):3:0.12. Controlling the mass ratio of divinylbenzene, styrene, kerosene, toluene, and initiator within this range allows the prepared porous resin matrix to have a more porous structure, making it more conducive to subsequent impregnation with the NTAamide (C8) extractant and further improving the adsorption performance of the NTA amide (C8) resin.

[0029] In the present invention, the mass ratio of the oil phase to the volume of the aqueous solution is preferably (13-17) g:300 mL. In one embodiment, the mass ratio of the oil phase to the volume of the aqueous solution can be specifically 13 g:300 mL, 14 g:300 mL, 15 g:300 mL, 16 g:300 mL, or 17 g:300 mL. By controlling the mass ratio of the oil phase to the volume of the aqueous solution within this range, the prepared porous resin matrix can have a larger particle size and better dispersibility.

[0030] In the present invention, the mixing of the aqueous phase solution, the oil phase and the initiator is preferably carried out by mixing the aqueous phase solution and the oil phase, and then adding the initiator.

[0031] In the present invention, the temperature of the suspension polymerization reaction is preferably 85-95°C; the time of the suspension polymerization reaction is preferably 9-11 hours; the suspension polymerization reaction is preferably carried out under stirring conditions; and the stirring speed is preferably 300-500 rpm. As an embodiment, the temperature of the suspension polymerization reaction can be specifically 85°C, 86°C, 87°C, 88°C, 89°C, 90°C, 91°C, 92°C, 93°C, 94°C or 95°C; the time of the suspension polymerization reaction can be specifically 9 hours, 9.5 hours, 10 hours, 10.5 hours or 11 hours; the stirring speed can be specifically 300 rpm, 350 rpm, 400 rpm, 450 rpm or 500 rpm.

[0032] As an embodiment, the suspension polymerization reaction is carried out in an oil bath and under condensation reflux conditions. The present invention controls the various parameters of the suspension polymerization reaction within the above ranges, which enables the suspension polymerization reaction to proceed fully.

[0033] After the suspension polymerization reaction is completed, the present invention preferably sequentially performs solid-liquid separation, washing, drying and sieving on the product of the suspension polymerization reaction to obtain a porous resin matrix.

[0034] The present invention has no particular limitation on the solid-liquid separation operation, and a solid can be obtained by using a solid-liquid separation technique well known to those skilled in the art. As an embodiment, the solid-liquid separation is suction filtration.

[0035] The present invention preferably uses water and anhydrous ethanol for washing in sequence. In the present invention, the temperature of the water during washing is preferably 80-100°C. The present invention has no particular limitation on the number and amount of water and anhydrous ethanol used for washing, as long as the impurities can be removed.

[0036] The present invention has no particular limitation on the drying operation, and drying to constant weight can be performed using a drying technique well known to those skilled in the art. In one embodiment, the drying temperature is 80° C., and the drying is performed in an oven.

[0037] In the present invention, the particle size of the porous resin matrix is preferably 100-200 μm. The present invention has no particular limitation on the sieving operation, and a sieving technique well known to those skilled in the art can be used to ensure that the particle size of the porous resin matrix after sieving is within the desired range.

[0038] The present invention controls the particle size of the porous resin matrix within the above range, which enables it to be filled with more NTAamide (C8) extractant, further improving the adsorption performance of the NTA amide (C8) resin.

[0039] The invention mixes oxalyl chloride, nitrilotriacetic acid, N,N-dimethylformamide and dichloromethane, and performs chlorination reaction to obtain an intermediate.

[0040] In the present invention, the mixing of oxalyl chloride, nitrilotriacetic acid (NTA), N,N-dimethylformamide (DMF) and dichloromethane is preferably as follows: NTA and dichloromethane are mixed to obtain an NTA solution, DMF is then added to obtain a mixed solution, and oxalyl chloride is then added dropwise to the mixed solution.

[0041] In the present invention, the mass ratio of the NTA to the volume of dichloromethane is preferably 3.8 g: (45-55) mL, more preferably 3.8 g: 50 mL.

[0042] In the present invention, the mass ratio of the NTA to the volume ratio of DMF is preferably 3.8 g: (450-550) μL, more preferably 3.8 g: 500 μL. In the present invention, the DMF is a catalyst.

[0043] In the present invention, the mass ratio of NTA to the volume ratio of oxalyl chloride is preferably 3.8 g: (28-32) mL, more preferably 3.8 g: 30 mL.

[0044] In the present invention, the dropping speed of the oxalyl chloride is preferably 0.4-0.6 mL / min, more preferably 0.5 mL / min.

[0045] In the present invention, the temperature of the chlorination reaction is preferably 35-45°C; the time of the chlorination reaction is preferably 6-8 hours; and the chlorination reaction is preferably carried out under stirring. The present invention does not specifically limit the stirring method and rate, and the stirring method and rate familiar to those skilled in the art can be adopted. As an embodiment, the temperature of the chlorination reaction can be specifically 35°C, 36°C, 37°C, 38°C, 39°C, 40°C, 41°C, 42°C, 43°C, 44°C or 45°C; the time of the chlorination reaction can be specifically 6 hours, 6.5 hours, 7 hours, 7.5 hours or 8 hours. The present invention controls the temperature and time of the chlorination reaction within the above ranges, so that the reaction can proceed fully.

[0046] After the acyl chlorination reaction is completed, the product of the acyl chlorination reaction is preferably subjected to reduced pressure distillation to obtain an intermediate.

[0047] The present invention has no particular limitation on the operation of the vacuum distillation. The unreacted raw materials and dichloromethane can be removed by using a vacuum distillation technique well known to those skilled in the art.

[0048] After obtaining the intermediate, the present invention mixes the intermediate with di-n-octylamine and dichloromethane to carry out an amidation reaction to obtain an NTA amide (C8) extractant.

[0049] In the present invention, the intermediate is preferably mixed with di-n-octylamine and dichloromethane by mixing the intermediate with part of the dichloromethane to obtain an intermediate solution, mixing the di-n-octylamine with the remaining dichloromethane to obtain a di-n-octylamine solution, and adding the intermediate solution dropwise to the di-n-octylamine solution.

[0050] In the present invention, the volume ratio of the mass of NTA to a portion of dichloromethane is preferably 3.8 g: (12-18) mL, more preferably 3.8 g: 15 mL.

[0051] In the present invention, the volume ratio of the di-n-octylamine to the remaining dichloromethane is preferably 4:(4-6), more preferably 4:5.

[0052] In the present invention, the volume ratio of the part of dichloromethane to the remaining dichloromethane is preferably 15:(45-55), more preferably 15:50.

[0053] In the present invention, the dropping speed of the intermediate solution is preferably 0.05-0.15 mL / min, more preferably 0.1 mL / min.

[0054] In the present invention, the temperature of mixing the intermediate with di-n-octylamine and dichloromethane is preferably ≤ 5°C.

[0055] In the present invention, the amidation reaction temperature is preferably ≤ 5°C; and the amidation reaction time is preferably 11 to 13 hours. In one embodiment, the amidation reaction time can be specifically 11 hours, 11.5 hours, 12 hours, 12.5 hours, or 13 hours. By controlling the amidation reaction temperature and time within the above ranges, the reaction can proceed fully.

[0056] After the amidation reaction is completed, the product of the amidation reaction is preferably subjected to a first water wash, an acid wash, an alkali wash, a second water wash, layered to obtain an organic layer, dried, concentrated under reduced pressure, and purified by a silica gel column to obtain an NTA amide (C8) extractant.

[0057] In the present invention, the water used in the first and second washings is preferably ultrapure water.

[0058] In the present invention, the acid used for pickling is preferably 0.5-1.5 mol / L hydrochloric acid, more preferably 1 mol / L hydrochloric acid.

[0059] In the present invention, the alkali for alkali washing is preferably a 0.5-1.5 mol / L sodium hydroxide solution, more preferably a 1 mol / L sodium hydroxide solution.

[0060] The present invention has no particular limitation on the amount of water, acid and alkali used and the number of washing times, as long as impurities such as unreacted raw materials can be removed.

[0061] The present invention has no special limitation on the operation of obtaining the organic layer by layering. The organic layer can be obtained by using a layering technical solution well known to those skilled in the art.

[0062] In the present invention, the organic layer is preferably dried using anhydrous sodium sulfate. The present invention has no particular limitation on the amount of anhydrous sodium sulfate used, and it only needs to remove the moisture from the organic layer.

[0063] The present invention has no particular limitation on the operation of the vacuum distillation, and the dichloromethane can be removed by using a vacuum distillation technique well known to those skilled in the art.

[0064] The present invention has no particular limitation on the operation of the silica gel column purification. Impurities can be removed using silica gel column purification techniques well known to those skilled in the art.

[0065] After obtaining a porous resin matrix and an NTA amide (C8) extractant, the present invention mixes the porous resin matrix and the NTAamide (C8) extractant with an isodecyl alcohol-n-dodecane mixed solution and an alcohol solvent, and sequentially performs shaking and vacuum infusion to obtain an NTA amide (C8) resin.

[0066] In the present invention, the mass ratio of the NTA amide (C8) extractant to the porous resin matrix is 1:(1-1.5). By controlling the mass ratio of the NTA amide (C8) extractant to the porous resin matrix within the aforementioned range, the present invention allows for a greater amount of NTA amide (C8) extractant to be impregnated into the porous resin matrix, further enhancing the adsorption performance of the NTA amide (C8) resin.

[0067] In the present invention, the volume ratio of isodecyl alcohol to n-dodecane in the isodecyl alcohol-n-dodecane mixed solution is preferably 1:(3.5-4.5), more preferably 1:4.

[0068] In the present invention, the mass ratio of the NTA amide (C8) extractant to the isodecyl alcohol-n-dodecane mixed solution is preferably 1:(0.9-1.1), more preferably 1:1. In the present invention, the isodecyl alcohol-n-dodecane mixed solution not only dissolves the NTA amide (C8) extractant but also enhances the binding force between the NTA amide (C8) extractant and the porous resin matrix. After subsequent vacuum infusion, the extractant partially remains on the surface and within the pores of the porous resin matrix, thereby increasing the hydrophobicity of the porous resin matrix and, in turn, improving the stability and adsorption of the NTA amide (C8) resin under highly acidic conditions.

[0069] In the present invention, the alcohol solvent is preferably ethanol or methanol.

[0070] In the present invention, the mass ratio of the NTA amide (C8) extractant to the alcohol solvent is preferably (1-5) g: (25-35) mL, more preferably (1-5) g: 30 mL. In the present invention, the alcohol solvent serves as a diluent, which facilitates the subsequent vacuum infusion of the NTA amide (C8) extractant into the pores of the porous resin matrix.

[0071] The present invention has no particular limitation on the mixing operation of the porous resin matrix, the NTA amide (C8) extractant, the isodecyl alcohol-n-dodecane mixed solution, and the alcohol solvent. A mixing technical solution well known to those skilled in the art can be used to ensure that the raw materials are evenly mixed.

[0072] In the present invention, the oscillation temperature is preferably room temperature; the oscillation time is preferably 22 to 25 hours, more preferably 24 hours.

[0073] In the present invention, the vacuum perfusion is preferably: subjecting the shaken mixed system to rotary evaporation under vacuum conditions.

[0074] In the present invention, the vacuum pressure is preferably 200-300 mbar; the rotary evaporation temperature is preferably 60-70°C, more preferably 65°C; the rotary evaporation speed is preferably 25-45 rpm, more preferably 40 rpm; and the rotary evaporation time is preferably 2-3 hours. By controlling the vacuum infusion parameters within the aforementioned ranges, the present invention allows the NTA amide (C8) extractant to penetrate more deeply into the pores of the porous resin matrix, making it less susceptible to dislodging under highly acidic conditions. This improves the stability and adsorption of the NTA amide (C8) resin under highly acidic conditions, while simultaneously removing the alcohol solvent and most of the isodecyl alcohol-n-dodecane mixed solution.

[0075] After the vacuum infusion is completed, the present invention preferably sequentially washes the vacuum infusion product with water and vacuum-dries it to obtain NTA amide (C8) resin.

[0076] In the present invention, the water used in the water washing is preferably ultrapure water. The present invention has no particular limitation on the amount of water used and the number of washing times, as long as the unreacted raw materials and impurities are removed.

[0077] In the present invention, the vacuum drying temperature is preferably 70-80°C; the vacuum drying time is preferably 22-25 hours, more preferably 24 hours. The vacuum degree of the vacuum drying is not particularly limited in the present invention, and any vacuum degree familiar to those skilled in the art can be used.

[0078] The present invention first prepares a porous resin matrix and an NTA amide (C8) extractant, and then uses vacuum infusion to impregnate the NTA amide (C8) extractant into the pores of the porous resin matrix, thereby preventing the NTA amide (C8) extractant from falling off during subsequent applications under highly acidic conditions, thereby improving the stability and adsorption of the NTA amide (C8) resin under highly acidic conditions. At the same time, the type of the porous resin matrix is controlled, which has good inertness, further improving the stability and adsorption of the NTA amide (C8) resin under highly acidic conditions, and the NTA amide (C8) resin has excellent selective adsorption for Th (IV).

[0079] The present invention also provides an NTA amide (C8) resin prepared by the preparation method described in the above technical solution, comprising a porous resin matrix and an NTA amide (C8) extractant loaded on the surface and inside the pores of the porous resin matrix.

[0080] The NTA amide (C8) resin prepared by the present invention has excellent stability and adsorption under highly acidic conditions, and simultaneously has excellent selective adsorption for Th (IV).

[0081] The present invention also provides the use of the NTA amide (C8) resin described in the above technical solution in adsorbing thorium ions (Th (IV)).

[0082] The present invention has no special limitation on the operation of the application, and the application technical solutions well known to those skilled in the art can be adopted.

[0083] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions of the present invention. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0084] Example 1 A method for preparing an NTA amide (C8) resin is as follows: (1) 3.5 g of gelatin (biotechnology grade, CAS: 9000-70-8, McLean), 0.35 g of calcium chloride and 300 mL of water are mixed (the mass ratio of gelatin, calcium chloride and water is 3.5:0.35:300), and stirred at 70°C and 300 rpm until the gelatin is completely dissolved to obtain an aqueous phase solution; 4 g of divinylbenzene and 1.5 g of styrene are mixed, and 6 g of kerosene (reagent grade, CAS: 8008-20-6, McLean) and 3 g of toluene are added to obtain an oil phase; the aqueous phase solution is stirred at 70°C and 300 rpm until the gelatin is completely dissolved. and the oil phase, adding 0.12 g of benzoyl peroxide (the mass ratio of divinylbenzene, styrene, kerosene, toluene and benzoyl peroxide is 4:1.5:6:3:0.12, and the volume ratio of the oil phase to the aqueous phase solution is 14.5 g:300 mL), and carrying out suspension polymerization in a 90°C oil bath, a stirring speed of 400 rpm and condensation reflux conditions for 10 hours. After the reaction, the solid is filtered off, and then washed with 90°C hot water and anhydrous ethanol in sequence, and then dried at 80°C. After sieving, a porous resin matrix with a particle size of 100-200 μm is obtained; (2) 3.8 g of NTA and 50 mL of dichloromethane were mixed to obtain an NTA solution, 500 μL of DMF was added to obtain a mixed solution, 30 mL of oxalyl chloride was added dropwise to the mixed solution at a rate of 0.5 mL / min at 30°C (the mass ratio of NTA to oxalyl chloride was 3.8 g:30 mL). After the addition was completed, the chlorination reaction was carried out at 40°C with stirring for 8 h, and the intermediate was obtained by vacuum distillation; (3) The intermediate was mixed with 15 mL of dichloromethane to obtain an intermediate solution, 40 mL of dioctylamine and 50 mL of dichloromethane were mixed (the volume ratio of dioctylamine to dichloromethane was 4:5) to obtain a dioctylamine solution, and the intermediate solution was added dropwise to the dioctylamine solution at a rate of 0.1 mL / min (the volume ratio of dichloromethane in the intermediate solution to dichloromethane in the dioctylamine solution was 15:50). The temperature of the entire mixing process was below 5°C, and then the mixture was refluxed at below 5°C for 12 hours, washed with ultrapure water, acid washed with 1 mol / L hydrochloric acid, alkaline washed with 1 mol / L sodium hydroxide solution and washed with ultrapure water in sequence, and the organic layer was separated by layers. The organic layer was dried over anhydrous sodium sulfate, concentrated under reduced pressure, and purified by silica gel column to obtain a yellow oily liquid NTAamide (C8) extractant; (4) 5 g of NTA amide (C8) extractant, isodecyl alcohol-n-dodecane mixed solution (the volume ratio of isodecyl alcohol and n-dodecane is 1:4, and the mass ratio of NTA amide (C8) extractant and isodecyl alcohol-n-dodecane mixed solution is 1:1) and anhydrous ethanol (the mass ratio of NTA amide (C8) extractant and the volume ratio of anhydrous ethanol is 5 g:30 mL) were mixed to obtain a mixed solution, and then 5 g of porous resin matrix (the mass ratio of NTA amide (C8) extractant and porous resin matrix is 1:1) was added. The mixture was shaken at room temperature for 24 h, and then rotary evaporated at 200 mbar, 65 ° C, and 40 rpm for 2 h. After washing with ultrapure water, it was vacuum dried at 80 ° C for 24 h to obtain NTA amide (C8) resin.

[0085] Comparative Example 1 The amount of NTA amide (C8) extractant in step (4) of Example 1 was replaced with 2.5 g. At this time, the mass ratio of NTA amide (C8) extractant to porous resin matrix was 1:2. Other parameters were the same as those in Example 1.

[0086] Comparative Example 2 The amount of NTA amide (C8) extractant in step (4) of Example 1 was replaced with 1.67 g. At this time, the mass ratio of NTA amide (C8) extractant to porous resin matrix was 1:3. Other parameters were the same as those in Example 1.

[0087] Comparative Example 3 The porous resin matrix in Comparative Example 1 was replaced with commercial silica (particle size 100-200 μm, Lanzhou Kent Chemical Technology Co., Ltd.), and other parameters were the same as those in Comparative Example 1.

[0088] Comparative Example 4 The porous resin matrix in Comparative Example 1 was replaced with commercial XAD-7 resin (particle size 100-200 μm, Lanzhou Kent Chemical Technology Co., Ltd.), and other parameters were the same as those in Comparative Example 1.

[0089] Comparative Example 5 The porous resin matrix in Example 1 was replaced with commercial silica (particle size 100-200 μm, Lanzhou Kent Chemical Technology Co., Ltd.), and other parameters were the same as in Example 1.

[0090] Comparative Example 6 The porous resin matrix in Example 1 was replaced with commercial XAD-7 resin (particle size 100-200 μm, Lanzhou Kent Chemical Technology Co., Ltd.), and other parameters were the same as in Example 1.

[0091] The Fourier transform infrared spectra of the porous resin matrix (Resin Matrix) and NTA amide (C8) resin (NTAamide (C8) Resin) prepared in Example 1 are as follows: Figure 1 shown. Figure 1 Medium 1462cm -1 The peak of CH bending vibration is 2820-2990cm -1 The aromatic and aliphatic -CH stretching vibration peaks are at 1440-1620 cm -1 Ring vibration of benzene ring, 670-930cm -1 The new characteristic peak is 1644 cm -1 The stretching vibration peak of -C=O is at 1120cm -1 The peak at 1 is the -CN stretching vibration peak, and the other two are characteristic peaks of amide functional groups, proving that the extractant NTA amide (C8) has been successfully impregnated into the porous resin matrix.

[0092] The SEM images of the porous resin matrix prepared in Example 1 at different magnifications are as follows: Figure 2 As shown, Figure 2 a in the figure is a SEM image of the porous resin matrix with a magnification of 70 times. Figure 2 b is a SEM image of the porous resin matrix at a magnification of 500 times; SEM images of the NTA amide (C8) resin prepared in Example 1 at different magnifications are shown in FIG. Figure 3 As shown, Figure 3 a in the figure is a SEM image of NTA amide (C8) resin with a magnification of 80 times. Figure 3 b is a SEM image of NTA amide (C8) resin at a magnification of 500 times.

[0093] from Figures 2 and 3 It can be seen that the appearance of the porous resin matrix is a spherical structure with distinct particles, while there is a small amount of polymer-like structure on the surface of the NTA amide (C8) resin. This is because the NTA amide (C8) extractant is not completely impregnated into the pores of the porous resin matrix.

[0094] The nitrogen adsorption-desorption curve of the porous resin matrix prepared in Example 1 is as follows: Figure 4 As shown, the pore size distribution is Figure 5 As shown in the figure, the vertical axis represents the change in pore volume per unit pore diameter.

[0095] The specific surface area of the porous resin matrix prepared in Example 1 is 455.88 m 2 / g, and the average pore diameter is 12.37nm.

[0096] The NTA amide (C8) resin prepared in Example 1 was mixed with thorium nitrate solutions with different nitric acid concentrations for adsorption. The solid-to-liquid ratio of the NTA amide (C8) resin to the thorium nitrate solution was 5 g / L, the concentration of Th (IV) was 1 ppm, the temperature was 25°C, the equilibrium time was 24 h, and the nitric acid concentrations were 0.01 mol / L, 0.05 mol / L, 0.1 mol / L, 0.5 mol / L, 1 mol / L, 2 mol / L, 3 mol / L, 4 mol / L, 5 mol / L, 6 mol / L, 7 mol / L, 8 mol / L, 9 mol / L and 10 mol / L, respectively. The adsorption rate and adsorption efficiency of the NTA amide (C8) resin prepared in Example 1 for Th (IV) at different nitric acid concentrations were as follows: K d Value Figure 6 As shown, K d The value is the distribution coefficient, which reflects the adsorption properties between the adsorbent and the adsorbate and is used to evaluate the affinity of the adsorbent for the adsorbate: ; in, C 0 (mg / L) is the initial concentration of Th(IV) in the solution, C e (mg / L) is the concentration of Th(Ⅳ) in the supernatant when the resin reaches adsorption equilibrium. V (mL) is the volume of Th(IV) solution added, m (g) is the mass of added resin.

[0097] from Figure 6It can be seen from the figure that the NTA amide (C8) resin prepared in Example 1 has a significant effect on the Th (IV) reaction at different nitric acid concentrations. K d The values are 4.09×10 6 mL / g, 2.97×10 4 mL / g, 1.59×10 4 mL / g,7.12×10 3 mL / g,8.13×10 3 mL / g,9.37×10 3 mL / g, 1.03×10 4 mL / g, 1.08×10 4 mL / g, 1.26×10 4 mL / g, 1.14×10 4 mL / g, 1.70×10 4 mL / g, 1.42×10 4 mL / g, 1.33×10 4 mL / g, 1.12×10 4 mL / g, all >10 3 mL / g, the adsorption rates for Th (IV) were 99.95%, 99.33%, 98.76%, 97.26%, 97.59%, 97.91%, 98.09%, 98.18%, 98.43%, 98.26%, 98.83%, 98.60%, 98.52% and 98.23%, respectively, all showing excellent adsorption effects.

[0098] The NTA amide (C8) resin prepared in Example 1 was mixed with thorium nitrate solutions of different nitric acid concentrations for adsorption. The solid-liquid ratio of the NTA amide (C8) resin to the thorium nitrate solution was 1 g / L, the concentration of Th (IV) was 100 ppm, the temperature was 25°C, the equilibrium time was 24 h, and the nitric acid concentrations were 0.01 mol / L, 0.05 mol / L, 0.1 mol / L, 0.5 mol / L, 1 mol / L, 2 mol / L, 3 mol / L, 4 mol / L, 5 mol / L, 6 mol / L, 7 mol / L, 8 mol / L, 9 mol / L and 10 mol / L, respectively. The adsorption capacity of the NTA amide (C8) resin prepared in Example 1 for Th (IV) at different nitric acid concentrations is shown in FIG. Figure 7 As shown. Figure 7It can be seen that under different nitric acid concentrations, the adsorption capacity of the NTA amide (C8) resin prepared in Example 1 for Th (IV) is 28.23 mg / g, 21.15 mg / g, 19.43 mg / g, 22.90 mg / g, 30.25 mg / g, 39.48 mg / g, 45.96 mg / g, 48.55 mg / g, 56.27 mg / g, 59.40 mg / g, 62.39 mg / g, 59.28 mg / g, 54.31 mg / g, and 47.04 mg / g, respectively. The NTA amide (C8) resin prepared in Example 1 has excellent adsorption capacity for Th (IV), especially under highly acidic conditions.

[0099] The NTA amide (C8) resin prepared in Example 1 was mixed with thorium nitrate solutions with different initial Th (IV) concentrations and a 7 mol / L nitric acid concentration for adsorption. The solid-to-liquid ratio of the NTA amide (C8) resin to the thorium nitrate solution was 5 g / L, the temperature was 25°C, the equilibrium time was 24 h, and the initial Th (IV) concentrations were 20 ppm, 40 ppm, 60 ppm, 80 ppm, 100 ppm, 120 ppm, 140 ppm, 160 ppm, 200 ppm, 250 ppm, 300 ppm, 350 ppm, and 400 ppm, respectively. The adsorption isotherms were fitted using the Langmuir and Freundlich models, and the results are shown in FIG. Figure 8 As shown. Figure 8 It can be seen that the fitting is more consistent with the Langmuir model, indicating that it is mainly monolayer adsorption.

[0100] The adsorption parameters of Th(Ⅳ) on NTA amide(C8) resin calculated according to the Langmuir and Freundlich models are shown in Table 1.

[0101] Table 1 Calculated adsorption parameters of Th(Ⅳ) on NTA amide (C8) resin based on Langmuir and Freundlich models

[0102] Note: Q in Table 1 m K is the maximum mass of Th(Ⅳ) adsorbed per gram of resin after reaching adsorption saturation under given conditions. L is the adsorption rate constant, R 2 is the correlation coefficient, K F is a parameter related to the relative adsorption capacity of the adsorbent, and n is a characteristic constant related to the adsorption intensity, which is an empirical value.

[0103] As can be seen from Table 1, through simulation calculation, the saturated adsorption capacity of Th(IV) on NTA amide(C8) resin at room temperature is 73.28 mg / g.

[0104] The NTA amide (C8) resin prepared in Example 1 was mixed with a thorium nitrate solution having a nitric acid concentration of 7 mol / L for adsorption. The solid-to-liquid ratio of the NTA amide (C8) resin to the thorium nitrate solution was 5 g / L, the concentration of Th (IV) was 1 ppm, and the temperature was 25°C. The adsorption rates of the NTA amide (C8) resin for Th (IV) at different adsorption times were as follows: Figure 9 As shown. Figure 9 It can be seen that at the adsorption time of 1min, 3min, 5min, 10min, 15min, 30min, 60min, 2h, 4h and 6h, the adsorption rates of NTA amide (C8) resin for Th (IV) are 10.60%, 25.94%, 43.36%, 52.75%, 57.33%, 74.56%, 83.53%, 83.70%, 85.18% and 83.76%, respectively. With the increase of adsorption time, the adsorption rate of NTA amide (C8) resin for Th (Ⅳ) shows a rapid upward trend with the extension of adsorption time. The adsorption site reaches saturation within 60 min, the curve tends to equilibrium, the adsorption rate remains basically unchanged, and reaches the maximum adsorption rate, which proves that the resin has fast adsorption kinetics and can reach adsorption equilibrium within 60 min.

[0105] The NTA amide (C8) resin prepared in Example 1 was mixed with thorium nitrate solutions containing interfering ions at different nitric acid concentrations for adsorption. The solid-to-liquid ratio of the NTA amide (C8) resin to the thorium nitrate solution containing interfering ions was 5 g / L, the concentration of Th (IV) was 1 ppm, the temperature was 25°C, the equilibrium time was 24 h, the nitric acid concentrations were 0.01 mol / L, 0.05 mol / L, 0.1 mol / L, 0.5 mol / L, 1 mol / L, 2 mol / L, 3 mol / L, 4 mol / L, 5 mol / L, 6 mol / L, 7 mol / L, 8 mol / L, 9 mol / L, and 10 mol / L, respectively. The interfering ions were Cs, Sr, Pb, Ba, Eu, Fe, Ru, La, Hg, Tl, Bi, Zr, and U, respectively. The distribution of different interfering ions on the NTA amide (C8) resin under different nitric acid concentrations is shown in the figure below. Figure 10 shown.

[0106] from Figure 10 As can be seen from the figure, the retention rate of interfering ions on NTA amide (C8) resin is very low.

[0107] The NTA amide (C8) resin prepared in Example 1 was mixed with a thorium nitrate solution containing interfering ions at a concentration of 3 mol / L nitric acid for adsorption. The solid-to-liquid ratio of the NTA amide (C8) resin to the thorium nitrate solution containing interfering ions was 5 g / L, the concentration of Th (IV) was 1 ppm, the temperature was 25°C, the equilibrium time was 24 h, the interfering ions were Cs, Sr, Pb, Ba, Eu, Fe, Cd, and U, and the concentration ratios of Th (IV) to the interfering ions were 1:1, 1:10, 1:100, and 1:200, respectively. The adsorption rate of Th (IV) by the NTAamide (C8) resin in the presence of different interfering ions is shown in FIG. Figure 11 As shown. Figure 11 It can be seen that even at a concentration as high as 200 times, the presence of Eu(Ⅲ) and Fe(Ⅲ) only slightly reduces the adsorption capacity of NTA amide(C8) resin for Th(Ⅳ), while other valence ions have almost no significant effect on the adsorption of Th(Ⅳ).

[0108] pass Figure 10 and Figure 11 It can be seen that the NTA amide (C8) resin prepared in the present invention has good selectivity for Th (IV) and can effectively identify and adsorb Th (IV) in complex systems.

[0109] The dynamic column performance of the NTA amide (C8) resin prepared in Example 1 was tested. The diameter and height of the chromatographic column were H×Φ=5cm×0.65cm, the amount of resin used was 0.2g, the concentration of Th(IV) in the thorium nitrate solution was 1ppm, the concentration of nitric acid was 7mol / L, the flow rate was 0.2mL / min, and the temperature was 25°C. The results are as follows: Figure 12 As shown. Figure 12 As can be seen from the results, the NTA amide (C8) resin column has a significant separation effect on Th(IV), with a high recovery rate. Using the same small amount of 0.5M HNO3 + 0.5M H2C2O4 solution for elution, over 96% of Th(IV) can be recovered. This demonstrates that NTA amide (C8) resin has a significant ability to enrich and recover Th(IV) from high-concentration HNO3 solutions.

[0110] The resins prepared in Example 1 and Comparative Examples 1, 2, 3, 4, and 6 were mixed with a thorium nitrate solution having a nitric acid concentration of 7 mol / L for adsorption. The solid-to-liquid ratio of the resin to the thorium nitrate solution was 5 g / L, the Th(IV) concentration was 1 ppm, the temperature was 25°C, and the equilibrium time was 24 h. The adsorption capacities of different resins for Th(IV) are shown in Table 2.

[0111] Table 2 Adsorption capacity of different resins for Th (IV)

[0112] As can be seen from Table 2, the NTA amide (C8) resin prepared in the present invention still has excellent adsorption effect under highly acidic conditions.

[0113] In summary, the NTA amide (C8) resin prepared in the present invention has excellent stability and adsorption properties under highly acidic conditions, and also has excellent selective adsorption for Th (IV).

[0114] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A method for preparing an adsorption resin, characterized in that: The following steps are involved: (1) gelatin, calcium chloride and water are mixed to obtain an aqueous phase solution; divinylbenzene, styrene, kerosene and toluene are mixed to obtain an oil phase; the aqueous phase solution, the oil phase and an initiator are mixed to carry out a suspension polymerization reaction to obtain a porous resin matrix; (2) mixing oxalyl chloride, nitrilotriacetic acid, N,N-dimethylformamide and dichloromethane, and performing an acyl chlorination reaction to obtain an intermediate; mixing the intermediate with dioctylamine and dichloromethane, and performing an amidation reaction to obtain an extractant; (3) mixing the porous resin matrix obtained in step (1), the extractant obtained in step (2), an isodecyl alcohol-n-dodecane mixed solution and an alcohol solvent, and sequentially performing oscillation and vacuum infusion to obtain an adsorption resin; the mass ratio of the extractant to the porous resin matrix is 1:(1-1.5); There is no order in which steps (1) and (2) are performed.

2. The preparation method according to claim 1, characterized in that The mass ratio of gelatin, calcium chloride and water in step (1) is (3-4): (0.3-0.4):

300.

3. The preparation method according to claim 1, characterized in that The mass ratio of divinylbenzene, styrene, kerosene, toluene and initiator in step (1) is (4-5): (1.2-1.5): (5-7): 3: 0.

12.

4. The preparation method according to claim 1, characterized in that The suspension polymerization reaction temperature in step (1) is 85-95° C., and the suspension polymerization reaction time is 9-11 hours.

5. The preparation method according to claim 1, characterized in that The temperature of the chlorination reaction in step (2) is 35-45° C., and the chlorination reaction time is 6-8 h.

6. The preparation method according to claim 1, characterized in that The temperature of the amidation reaction in step (2) is ≤5°C, and the amidation reaction time is 11-13 hours.

7. The preparation method according to claim 1, characterized in that The volume ratio of isodecyl alcohol to n-dodecane in the isodecyl alcohol-n-dodecane mixed solution in step (3) is 1:(3.5-4.5).

8. The preparation method according to claim 7, characterized in that In step (3), the mass ratio of the extractant to the isodecyl alcohol-n-dodecane mixed solution is 1:(0.8-1.0).

9. The adsorption resin prepared by the preparation method according to any one of claims 1 to 8, comprising a porous resin matrix and an extractant supported on the surface and inside the pores of the porous resin matrix.

10. Use of the adsorption resin according to claim 9 in adsorbing thorium ions.

Images