A method for preparing an irradiated thermosensitive ruthenium-ethylenediaminetetraacetic acid imprinted polymer

Abstract

This invention relates to a method for preparing an irradiated thermosensitive ruthenium-ethylenediaminetetraacetic acid (EDTA) imprinted polymer. The method first uses reversible addition-fragmentation chain transfer polymerization to prepare a linear thermosensitive polymer, poly(N,N-diethylacrylamide). Then, the poly(N,N-diethylacrylamide) is used as a RAFT reagent to synthesize a thermosensitive block with acrylamide. Finally, the thermosensitive block is co-dissolved in an aqueous methanol solution with acrylamide, acrylic acid, N,N-methylenebisacrylamide, and a ruthenium-EDTA complex. The thermosensitive block is then introduced through cobalt-60 irradiation solution polymerization to obtain the thermosensitive ruthenium-EDTA complex imprinted polymer. This invention is characterized by its short preparation time, environmental friendliness, and high production efficiency. The adsorbent prepared using the obtained thermosensitive ruthenium-EDTA imprinted polymer exhibits a rapid adsorption rate.

Description

Technical Field

[0001] This invention relates to the field of precious metal recycling, and more particularly to a method for preparing an irradiated thermosensitive ruthenium-ethylenediaminetetraacetic acid imprinted polymer. Background Technology

[0002] Ruthenium belongs to the platinum group elements and is the least abundant of the platinum group metals, with a content of only 10 ppm in the Earth's crust. -3 Ruthenium is widely used in aerospace, chemical, electronics, and pharmaceutical industries due to its excellent physical and chemical properties, and its demand and applications are increasing year by year. However, my country has very limited natural ruthenium reserves and is heavily reliant on imports. Therefore, researching ways to broaden the sources of ruthenium is of significant strategic importance to ensure the security of my country's ruthenium supply.

[0003] Currently, the ruthenium content in secondary resources is much higher than that in primary resources. Therefore, recovering ruthenium from ruthenium-containing secondary resources can not only protect the environment but also realize the recycling of ruthenium resources. However, the leachate composition of secondary resources is complex, and traditional methods for separating and enriching ruthenium generally have poor selectivity. Therefore, complicated pretreatment is required before separation and enrichment, which leads to problems such as low efficiency of existing technologies, long process flow, environmental pollution, and difficulty in industrial application. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a method for preparing irradiated temperature-sensitive ruthenium-ethylenediaminetetraacetic acid imprinted polymer that is quick, environmentally friendly and has high production efficiency.

[0005] To address the aforementioned problems, the present invention provides a method for preparing an irradiated thermosensitive ruthenium-ethylenediaminetetraacetic acid (RDA) imprinted polymer, characterized in that: the method first uses reversible addition-fragmentation chain transfer polymerization (RAFT) to prepare a linear thermosensitive polymer, poly(N,N-diethylacrylamide) (PDEA); then, the PEA is used as a RAFT reagent to synthesize a thermosensitive block (PDEA-bP(DEA-co-AM)) with acrylamide (AM); finally, the thermosensitive block is co-dissolved in an aqueous methanol solution with acrylamide, acrylic acid, N,N-methylenebisacrylamide, and a ruthenium-ethylenediaminetetraacetic acid complex, and the thermosensitive block is introduced by solution polymerization under cobalt-60 irradiation to obtain the thermosensitive ruthenium-ethylenediaminetetraacetic acid complex imprinted polymer (Ru(III)-EDTA-TIIP).

[0006] The poly(N,N-diethylacrylamide) (PDEA) is prepared by the following method: azobisisobutyronitrile, 2-(dodecyltrithiocarbonate)-2-methylpropionic acid and N,N-diethylacrylamide are dissolved in excess ethyl acetate, mixed evenly, and then sealed after passing nitrogen gas with a purity of 99.999% for 15-20 minutes. The mixture is stirred in an oil bath at 60-80°C for 30-40 hours. After the reaction is completed, the reaction product is subjected to a triple dissolution and triple precipitation process using ethyl acetate as solvent and n-hexane as precipitant. The molar ratio of azobisisobutyronitrile, 2-(dodecyltrithiocarbonate)-2-methylpropionic acid and N,N-diethylacrylamide is 1:(15-25):(950-1050).

[0007] The thermosensitive block was prepared by the following method: azobisisobutyronitrile, poly(N,N-diethylacrylamide) (PDEA), acrylamide, and N,N-diethylacrylamide were co-dissolved in excess N,N-dimethylformamide, mixed evenly, and then sealed after being purged with nitrogen gas of 99.999% purity for 15-20 minutes. The mixture was stirred and reacted in an oil bath at 60-80°C for 30-40 hours. The mixture was then subjected to a triple dissolution and triple precipitation process using ethyl acetate as solvent and n-hexane as precipitant, and subsequently dried under vacuum to constant weight. The molar ratio of azobisisobutyronitrile, poly(N,N-diethylacrylamide) (PDEA), and acrylamide was 1:(15-25):(950-1050); the molar ratio of N,N-diethylacrylamide to acrylamide was 1:1.5-1:2.5.

[0008] The thermosensitive ruthenium-ethylenediaminetetraacetic acid (EDTA) imprinted polymer was prepared by the following method: The thermosensitive block copolymer, acrylamide, acrylic acid, and the ruthenium-EDTA complex were co-dissolved in an excess methanol-water solution at a volume ratio of 2:1. After self-assembly in a water bath at 30-35°C for 1-2 hours, the crosslinking agent N,N-methylenebisacrylamide was added, and 99.999% pure nitrogen gas was introduced for 15-20 minutes before sealing. Then, the polymer was incubated at 30-40°C at a flow rate of 8 kGy / h. The irradiation dose was used to initiate polymerization with cobalt-60 irradiation for 5 hours. After polymerization, the product was vacuum dried to constant weight to obtain the final product. The mass ratio of the thermosensitive block to the acrylic acid was 1:5 to 1:20. The molar ratio of the acrylamide to the acrylic acid was 1:2 to 2:1. The molar ratio of the acrylic acid to the N,N-methylenebisacrylamide was 1:5 to 1:7. The amount of the ruthenium-ethylenediaminetetraacetic acid complex added accounted for 3.6% to 11% of the molar amount of the acrylic acid.

[0009] An adsorbent prepared from a thermosensitive ruthenium-ethylenediaminetetraacetic acid imprinted polymer obtained by the method described above.

[0010] The method for preparing an adsorbent as described above is characterized by the following: the thermosensitive ruthenium-ethylenediaminetetraacetic acid (EDTA) imprinted polymer is crushed, and the particles after passing through a 30-120 mesh sieve are placed in a 500 mesh filter bag and placed in a Soxhlet extractor. The ruthenium-EDTA complex is eluted with analytical grade anhydrous ethanol as the eluent, and the concentration of the corresponding ruthenium-EDTA complex in the etching solution is determined by ICP-AES. Elution is stopped when the test value is lower than 0.02 μg / mL. The filter bag is then rinsed alternately with methanol and water until the solution is neutral, and then vacuum dried to constant weight to obtain the adsorbent.

[0011] Compared with the prior art, the present invention has the following advantages:

[0012] 1. This invention uses cobalt-60 irradiation field to prepare imprinted polymers, which can be carried out at room temperature or near room temperature. High-energy rays can quickly initiate the polymerization reaction, enabling the irradiation polymerization to be completed in a short time, thus improving production efficiency. In addition, irradiation polymerization does not require the addition of chemical initiators, and the resulting material has no residue, making the entire process green, low-energy consumption, and low-cost.

[0013] 2. The present invention has a short preparation time and is environmentally friendly. The thermosensitive ruthenium imprinted polymer obtained has the characteristic of structural stability.

[0014] 3. The adsorbent prepared using the thermosensitive ruthenium-ethylenediaminetetraacetic acid imprinted polymer described in this invention has a faster adsorption rate. Due to the introduction of the thermosensitive block [poly(N,N-diethylacrylamide-g-poly(N,N-diethylacrylamide-g-acrylamide)], when the ambient temperature changes, the thermosensitive block undergoes a sol / gel phase transition, which changes the imprinted pores. Thus, by adjusting the temperature, a high level of adsorption and desorption can be achieved. Attached Figure Description

[0015] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0016] Figure 1 This is a flowchart illustrating the preparation process of the present invention.

[0017] Figure 2 This is a physical image of the thermosensitive ruthenium-ethylenediaminetetraacetic acid imprinted polymer prepared in Example 1 of this invention.

[0018] Figure 3 The images show SEM images of the thermosensitive ruthenium-ethylenediaminetetraacetic acid imprinted polymer (left) and the non-imprinted polymer (right) prepared in Example 1 of this invention.

[0019] Figure 4 This is a graph showing the adsorption performance of adsorbent A prepared in Example 1 of this invention as a function of time at different temperatures.

[0020] Figure 5 This is a graph showing the desorption performance of adsorbent A prepared in Example 1 of this invention as a function of time at different temperatures.

[0021] Figure 6 This is a graph showing the reusability of adsorbent A prepared in Example 1 of this invention. Detailed Implementation

[0022] like Figure 1 As shown, a method for preparing an irradiated thermosensitive ruthenium-ethylenediaminetetraacetic acid (RDA) imprinted polymer is described. The method first uses reversible addition-fragmentation chain transfer polymerization (RAFT) to prepare a linear thermosensitive polymer, poly(N,N-diethylacrylamide) (PDEA). Then, PEA is used as a RAFT reagent to synthesize a thermosensitive block (PDEA-bP(DEA-co-AM)) with acrylamide (AM). Finally, the thermosensitive block is co-dissolved with acrylamide, acrylic acid, N,N-methylenebisacrylamide, and a ruthenium-EDTA complex in an aqueous methanol solution. The thermosensitive block is then introduced through cobalt-60 irradiation solution polymerization to obtain the thermosensitive ruthenium-EDTA complex imprinted polymer (Ru(III)-EDTA-TIIP). The specific process is as follows:

[0023] Poly(N,N-diethylacrylamide) (PDEA) is prepared by the following method: Azobisisobutyronitrile (AIB), 2-(dodecyltrithiocarbonate)-2-methylpropionic acid, and N,N-diethylacrylamide are dissolved in excess ethyl acetate, mixed thoroughly, and then sealed after passing nitrogen gas of 99.999% purity through the solution for 15-20 minutes. The mixture is then stirred in an oil bath at 60-80°C for 30-40 hours. After the reaction is complete, the product is subjected to a triple dissolution and triple precipitation process using ethyl acetate as the solvent and n-hexane as the precipitant. The molar ratio of AIB, 2-(dodecyltrithiocarbonate)-2-methylpropionic acid, and N,N-diethylacrylamide is 1:(15-25):(950-1050), preferably 1:20:1000.

[0024] Thermosensitive block copolymer [poly(N,N-diethylacrylamide-g-poly(N,N-diethylacrylamide-g-acrylamide), PDEA-bP(DEA-co-AM)] was prepared by the following method: azobisisobutyronitrile, poly(N,N-diethylacrylamide) (PDEA), acrylamide and N,N-diethylacrylamide were co-dissolved in excess N,N-dimethylformamide, mixed evenly, and then sealed after passing nitrogen gas with a purity of 99.999% for 15-20 min. The mixture was stirred and reacted in an oil bath at 60-80℃ for 30-40 h. The mixture was then subjected to a triple dissolution and triple precipitation process using ethyl acetate as solvent and n-hexane as precipitant, and finally dried under vacuum to constant weight to obtain the final product. The molar ratio of azobisisobutyronitrile, poly(N,N-diethylacrylamide) (PDEA) and acrylamide is 1:(15~25):(950~1050), preferably 1:20:1000; the molar ratio of N,N-diethylacrylamide to acrylamide is 1:1.5~1:2.5, preferably 1:2.

[0025] The thermosensitive ruthenium-ethylenediaminetetraacetic acid (Ru(III)-EDTA-TIIP) imprinted polymer was prepared by the following method: The thermosensitive block, acrylamide, acrylic acid and ruthenium-ethylenediaminetetraacetic acid complex were co-dissolved in an excess methanol aqueous solution with a volume ratio (ml / ml) of 2:1. After self-assembly in a water bath at 30~35℃ for 1~2h, the crosslinking agent N,N-methylenebisacrylamide was added, and nitrogen gas with a purity of 99.999% was purged for 15~20min and then sealed. Then, the polymerization was initiated by cobalt-60 irradiation at 30~40℃ and an irradiation dose of 8KGy / h for 5h. After the polymerization was completed, the polymer was vacuum dried to constant weight to obtain the final product. The mass ratio (g / g) of the thermosensitive block to acrylic acid is 1:5 to 1:20; the molar ratio of acrylamide to acrylic acid is 1:2 to 2:1; the molar ratio of acrylic acid to N,N-methylenebisacrylamide is 1:5 to 1:7; and the amount of ruthenium-ethylenediaminetetraacetic acid complex added accounts for 3.6% to 11% of the molar amount of acrylic acid.

[0026] The ruthenium-ethylenediaminetetraacetic acid complex, i.e. the template ion, was prepared according to the method disclosed in ZL 201810386065.2.

[0027] An adsorbent prepared using a thermosensitive ruthenium-ethylenediaminetetraacetic acid imprinted polymer, the preparation method of which is as follows:

[0028] The thermosensitive ruthenium-ethylenediaminetetraacetic acid (EDTA) imprinted polymer was crushed, and the particles were placed in a 500-mesh filter bag after passing through a 30-120 mesh sieve. The bag was then placed in a Soxhlet extractor, and the ruthenium-EDTA complex was eluted with analytical grade anhydrous ethanol as the eluent. The concentration of the corresponding ruthenium-EDTA complex in the etching solution was determined by ICP-AES. Elution was stopped when the measured value was below 0.02 μg / mL. The filter bag was then rinsed alternately with methanol and water until the solution was neutral, and then vacuum dried to constant weight to obtain the adsorbent.

[0029] Example 1

[0030] Weigh 0.006 g of azobisisobutyronitrile (AIB), 0.258 g of 2-(dodecyltrithiocarbonyl)-2-methylpropionic acid (RAFT reagent), and 4.54 g of N,N-diethylacrylamide (DEA). Dissolve all three in 9.423 g of ethyl acetate in a 25 mL test tube. Mix thoroughly, purge with 99.999% pure nitrogen gas for 20 min at room temperature, seal, and react in a 70°C oil bath with stirring for 36 h. After the reaction is complete, use ethyl acetate as solvent and n-hexane as precipitant to perform a three-stage dissolution and precipitation process on the initial product to obtain poly(N,N-diethylacrylamide) (PDEA).

[0031] 0.003 g of azobisisobutyronitrile (AIB), 1.3104 g of poly(N,N-diethylacrylamide) (PDEA), and 0.6486 g of acrylamide were weighed and completely dissolved in 2.6804 g of N,N-dimethylformamide in a 25 mL test tube. Then, 0.4972 g of N,N-diethylacrylamide (DEA) was added, and the mixture was thoroughly mixed. The mixture was then sealed after passing 99.999% pure nitrogen gas through the tube for 20 min at room temperature, and stirred in a 70°C oil bath for 36 h. A mixture of ethyl acetate and n-hexane (1:4 volume ratio) was used as a precipitant, and the mixture underwent a triple dissolution and triple precipitation process. Subsequently, the mixture was placed in a vacuum oven at 40°C until constant weight was achieved, yielding the thermosensitive block [poly(N,N-diethylacrylamide-g-poly(N,N-diethylacrylamide-g-acrylamide)], PDEA-bP(DEA-co-AM).

[0032] Weigh 0.1g of thermosensitive block copolymer, 0.56g of acrylamide, 0.5g of acrylic acid, and 0.2g of ruthenium-ethylenediaminetetraacetic acid complex and dissolve them in a mixed solvent of water and methanol at a volume ratio of 1:2. The mixture is then self-assembled for 2 hours in a constant temperature water bath at 35℃ with magnetic stirring at 150 r / min. 6g of N,N-methylenebisacrylamide is added and stirred until completely dissolved. Nitrogen gas of 99.999% purity is introduced at room temperature for 20 minutes, and the mixture is then sealed to form a solution system. After polymerization under cobalt-60 irradiation for 5 hours, the polymer is removed and dried in a vacuum drying oven to constant weight, yielding the thermosensitive ruthenium-ethylenediaminetetraacetic acid imprinted polymer (Ru(III)-EDTA-TIIP). Figure 2 As shown.

[0033] The preparation of the nonionic imprinted polymer (Ru(III)-EDTA-TINP) is the same as described above except that the ruthenium-ethylenediaminetetraacetic acid complex is not added.

[0034] Electron microscopy was performed on the obtained thermosensitive ruthenium-ethylenediaminetetraacetic acid imprinted polymer (Ru(III)-EDTA-TIIP) and the non-imprinted polymer (Ru(III)-EDTA-TINP). The results are as follows: Figure 3 As shown in the figure, numerous pores are observed on the Ru(III)-EDTA-TIIP surface, and the pores are relatively loosely distributed. In contrast, the Ru(III)-EDTA-TINP surface shows no obvious pores and is densely packed. This morphological difference stems from two main factors: firstly, the self-assembly between the ruthenium-ethylenediaminetetraacetic acid (EDTA) complex and the functional monomers leads to changes in the interfacial interactions between polymer microparticles; secondly, the hydrogen bonding between the functional monomers and the ruthenium-EDTA-TIIP complex weakens the hydrogen bonds between polymer molecular chains, resulting in reduced forces between the polymer and the solvent, making phase separation easier, thus leading to more pores and a looser surface.

[0035] The dried Ru(III)-EDTA-TIIP was pulverized using a pulverizer, and particles with a mesh size of 30-120 were sieved and stored. The particles were then placed in a 500-mesh filter bag (7.6×50mm) and placed in a Soxhlet extractor to elute the ruthenium-ethylenediaminetetraacetic acid complex with anhydrous ethanol. The concentration of the corresponding ruthenium-ethylenediaminetetraacetic acid complex in the etching solution was determined by inductively coupled plasma atomic emission spectrometry (ICP-AES). Elution was stopped when the measured value was below 0.02 μg / mL. The filter bag was then rinsed alternately with methanol and water until the solution was neutral and dried under vacuum at 45℃ to constant weight. After drying, adsorbent A was obtained.

[0036] Figure 4 The figure shows the adsorption kinetics of Ru(III)-EDTA ions for adsorbent A at 25℃, 35℃, and 45℃. The figure shows that Ru(III)-EDTA-TIIP exhibits a higher adsorption capacity at 35℃ compared to 25℃ and 45℃. This is because the introduction of the thermosensitive block ensures that the imprinted pores remain intact during the self-assembly of GIS-SIIP at 35℃. When the external temperature changes, the thermosensitive block undergoes a sol / gel phase transition, causing the imprinted pores to expand and contract, thus reducing the adsorption capacity.

[0037] Figure 5The figure shows the amount of Ru(III)-EDTA desorbed by adsorbent A over time. The figure shows that Ru(III)-EDTA-TIIP exhibits a higher desorption capacity at 25℃ compared to 35℃ and 45℃. When the adsorption temperature T = 25℃ (below the LCST of the thermosensitive block), the molecular chains are in a stretched state, causing the imprinted pores to expand, resulting in poorer integrity of the imprinted pores and a poorer spatial fit between the imprinted pores and the target ion. The imprinted sites are incompletely imprinted sites, and the affinity of the imprinted pores for the ruthenium-ethylenediaminetetraacetic acid complex is weakened. Therefore, the adsorbed ruthenium-ethylenediaminetetraacetic acid complex is easily desorbed.

[0038] The synthesis method of Ru(III)-EDTA is as follows: RuCl3 is added to EDTA in a molar ratio of 1:1. After complete dissolution, the mixture is heated in a water bath at 60°C with magnetic stirring and reacted by reflux for 2 hours. The product is then precipitated with 90% ethanol, filtered to obtain the precipitate, and then vacuum dried in a drying oven at 60°C for 24 hours.

[0039] An equal volume of Ru(III)-EDTA solution with a molar concentration of 0.013 mmol / L was taken, and the ion concentration in the solution before adsorption was determined by inductively coupled plasma mass spectrometry (ICP-MS). 0.1 g of adsorbent A was adsorbed at 35 °C for 120 min, then placed in a 1% NH3•H2O solution and desorbed at 25 °C for 300 min. This adsorption-desorption cycle was repeated 12 times, and the ion concentrations after adsorption and desorption were determined by ICP-MS. The results are as follows: Figure 6 As shown in the figure, after 8 adsorption-desorption cycles, the adsorption amount did not change significantly from the original value, indicating that the thermosensitive ruthenium-ethylenediaminetetraacetic acid imprinted polymer prepared by the method of this invention has good reusability.

[0040] Example 2

[0041] Weigh 0.002 g of azobisisobutyronitrile (AIB), 0.086 g of 2-(dodecyltrithiocarbonyl)-2-methylpropionic acid (RAFT reagent), and 1.513 g of N,N-diethylacrylamide (DEA). Dissolve all of these in 3.141 g of ethyl acetate in a 25 mL test tube. Mix thoroughly, purge with 99.999% pure nitrogen gas for 20 min at room temperature, then seal the tube and stir in a 70°C oil bath for 36 h. After the reaction is complete, use ethyl acetate as solvent and n-hexane as precipitant to perform a three-stage dissolution and precipitation process on the initial product to obtain poly(N,N-diethylacrylamide) (PDEA).

[0042] 0.006 g of azobisisobutyronitrile (AIB), 2.621 g of poly(N,N-diethylacrylamide) (PDEA), and 1.2972 g of acrylamide were weighed and completely dissolved in 5.3608 g of N,N-dimethylformamide in a 25 mL test tube. Then, 0.9944 g of N,N-diethylacrylamide (DEA) was added, and the mixture was thoroughly mixed. The mixture was then sealed after passing 99.999% pure nitrogen gas through the tube for 20 min at room temperature, and stirred in a 70°C oil bath for 36 h. A mixture of ethyl acetate and n-hexane (1:4 volume ratio) was used as a precipitant, and the mixture underwent a triple dissolution and triple precipitation process. Subsequently, the mixture was placed in a vacuum oven at 40°C until constant weight was achieved, yielding the thermosensitive block [poly(N,N-diethylacrylamide-g-poly(N,N-diethylacrylamide-g-acrylamide)], PDEA-bP(DEA-co-AM).

[0043] 0.05 g of thermosensitive block copolymer, 0.56 g of acrylamide, 1.0 g of acrylic acid, and 0.3 g of ruthenium-ethylenediaminetetraacetic acid complex were weighed and dissolved in a mixed solvent of water and methanol at a volume ratio of 1:2. The mixture was self-assembled for 2 h in a constant temperature water bath at 35 °C with magnetic stirring at 150 r / min. 7 g of N,N-methylenebisacrylamide was added and stirred until completely dissolved. Nitrogen gas of 99.999% purity was passed through the solution at room temperature for 20 min, and then the solution was sealed. After polymerization under cobalt-60 irradiation for 5 h, the polymer was removed and dried in a vacuum drying oven to constant weight, yielding the thermosensitive ruthenium-ethylenediaminetetraacetic acid imprinted polymer (Ru(III)-EDTA-TIIP).

[0044] The dried Ru(III)-EDTA-TIIP was pulverized using a multi-functional pulverizer, and particles of 30-120 mesh were sieved and stored. The particles were placed in a 500-mesh filter bag (7.6×50 mm) and eluted with anhydrous ethanol in a Soxhlet extractor. The concentration of the corresponding Ru-EDTA-TIIP complex in the etching solution was determined by inductively coupled plasma atomic emission spectrometry (ICP-AES). Elution was stopped when the measured value was below 0.02 μg / mL. The filter bag was then rinsed alternately with methanol and water until the solution was neutral and dried under vacuum at 45℃ to constant weight. Adsorbent B was obtained after drying.

[0045] Example 3

[0046] Weigh 0.004 g of azobisisobutyronitrile (AIB), 0.172 g of 2-(dodecyltrithiocarbonyl)-2-methylpropionic acid (RAFT reagent), and 3.027 g of N,N-diethylacrylamide (DEA). Dissolve all three in 6.282 g of ethyl acetate in a 25 mL test tube. Mix thoroughly, purge with 99.999% pure nitrogen gas for 20 min at room temperature, seal, and react in a 70°C oil bath with stirring for 36 h. After the reaction is complete, use ethyl acetate as solvent and n-hexane as precipitant to perform a three-stage dissolution and precipitation process on the initial product to obtain poly(N,N-diethylacrylamide) (PDEA).

[0047] 0.005 g of azobisisobutyronitrile (AIB), 2.184 g of poly(N,N-diethylacrylamide) (PDEA), and 1.081 g of acrylamide were weighed and completely dissolved in a 25 mL test tube with 4.4673 g of N,N-dimethylformamide. Then, 0.8287 g of N,N-diethylacrylamide (DEA) was added, and the mixture was thoroughly mixed. The mixture was then sealed after passing 99.999% pure nitrogen gas through the tube for 20 min at room temperature and stirred in a 70 °C oil bath for 36 h. A mixture of ethyl acetate and n-hexane (volume ratio 1:4) was used as a precipitant, and the mixture underwent a triple dissolution and triple precipitation process. Subsequently, the mixture was placed in a vacuum oven at 40 °C until constant weight was achieved, yielding the thermosensitive block [poly(N,N-diethylacrylamide-g-poly(N,N-diethylacrylamide-g-acrylamide)], denoted as PDEA-bP(DEA-co-AM).

[0048] 0.05 g of thermosensitive block copolymer, 1.12 g of acrylamide, 0.5 g of acrylic acid, and 0.1 g of ruthenium-ethylenediaminetetraacetic acid complex were weighed and dissolved in a mixed solvent of water and methanol at a volume ratio of 1:2. The mixture was self-assembled for 2 h in a constant temperature water bath at 35 °C with magnetic stirring at 150 r / min. Then, 5.5 g of N,N-methylenebisacrylamide was added and stirred until completely dissolved. Nitrogen gas of 99.999% purity was passed through the solution at room temperature for 20 min, and then the solution was sealed. After polymerization under cobalt-60 irradiation for 5 h, the polymer was removed and dried in a vacuum drying oven to constant weight, yielding the thermosensitive ruthenium-ethylenediaminetetraacetic acid imprinted polymer (Ru(III)-EDTA-TIIP).

[0049] The dried Ru(III)-EDTA-TIIP was pulverized using a multi-functional pulverizer, and particles of 30-120 mesh were sieved and stored. The particles were then placed in a 500-mesh filter bag (7.6×50 mm) and eluted with anhydrous ethanol in a Soxhlet extractor. The concentration of the corresponding Ru-EDTA-TIIP complex in the etching solution was determined by inductively coupled plasma atomic emission spectrometry (ICP-AES). Elution was stopped when the measured value was below 0.02 μg / mL. The filter bag was then rinsed alternately with methanol and water until the solution was neutral and dried under vacuum at 45 °C to constant weight. The adsorbent C was obtained after drying.

Claims

1. A method for preparing an irradiated thermosensitive ruthenium-ethylenediaminetetraacetic acid imprinted polymer, characterized in that: This method first prepares a linear thermosensitive polymer, poly(N,N-diethylacrylamide), using reversible addition-fragmentation chain transfer polymerization. Then, the poly(N,N-diethylacrylamide) is used as a RAFT reagent to synthesize a thermosensitive block with acrylamide. Finally, the thermosensitive block is co-dissolved in an aqueous methanol solution with acrylamide, acrylic acid, N,N-methylenebisacrylamide, and a ruthenium-ethylenediaminetetraacetic acid (EDTA) complex. The thermosensitive block is introduced through cobalt-60 irradiation solution polymerization to obtain a thermosensitive ruthenium-EDTA complex-imprinted polymer. The synthesis method of the ruthenium-EDTA complex is as follows: RuCl3 is added to EDTA at a molar ratio of 1:

1. After complete dissolution, the mixture is heated in a water bath at 60°C under magnetic stirring and reacted under reflux for 2 hours. Precipitation is achieved with 90% ethanol, filtered, and the product is then vacuum-dried in a drying oven at 60°C for 24 hours.

2. The method for preparing an irradiated thermosensitive ruthenium-ethylenediaminetetraacetic acid imprinted polymer as described in claim 1, characterized in that: The poly(N,N-diethylacrylamide) is prepared by the following method: azobisisobutyronitrile, 2-(dodecyltrithiocarbonate)-2-methylpropionic acid and N,N-diethylacrylamide are dissolved in excess ethyl acetate, mixed evenly, and then sealed after passing nitrogen gas with a purity of 99.999% for 15-20 minutes. The mixture is stirred in an oil bath at 60-80°C for 30-40 hours. After the reaction is completed, the reaction product is subjected to a triple dissolution and triple precipitation process using ethyl acetate as solvent and n-hexane as precipitant. The molar ratio of azobisisobutyronitrile, 2-(dodecyltrithiocarbonate)-2-methylpropionic acid and N,N-diethylacrylamide is 1:(15-25):(950-1050).

3. The method for preparing an irradiated thermosensitive ruthenium-ethylenediaminetetraacetic acid imprinted polymer as described in claim 1, characterized in that: The thermosensitive block was prepared by the following method: azobisisobutyronitrile, poly(N,N-diethylacrylamide), acrylamide, and N,N-diethylacrylamide were co-dissolved in excess N,N-dimethylformamide, mixed evenly, and then sealed after being purged with nitrogen gas of 99.999% purity for 15-20 minutes. The mixture was stirred and reacted in an oil bath at 60-80°C for 30-40 hours. The mixture was then subjected to a triple dissolution and triple precipitation process using ethyl acetate as solvent and n-hexane as precipitant, and subsequently dried under vacuum to constant weight. The molar ratio of azobisisobutyronitrile, poly(N,N-diethylacrylamide), and acrylamide was 1:(15-25):(950-1050); the molar ratio of N,N-diethylacrylamide to acrylamide was 1:1.5-1:2.

5.

4. The method for preparing an irradiated thermosensitive ruthenium-ethylenediaminetetraacetic acid imprinted polymer as described in claim 1, characterized in that: The thermosensitive ruthenium-ethylenediaminetetraacetic acid (EDTA) imprinted polymer was prepared by the following method: The thermosensitive block copolymer, acrylamide, acrylic acid, and the ruthenium-EDTA complex were co-dissolved in an excess methanol-water solution at a volume ratio of 2:

1. After self-assembly in a water bath at 30-35°C for 1-2 hours, the crosslinking agent N,N-methylenebisacrylamide was added, and 99.999% pure nitrogen gas was introduced for 15-20 minutes before sealing. Then, the polymer was incubated at 30-40°C at a flow rate of 8 kGy / h. The irradiation dose was used to initiate polymerization with cobalt-60 irradiation for 5 hours. After polymerization, the product was vacuum dried to constant weight to obtain the final product. The mass ratio of the thermosensitive block to the acrylic acid was 1:5 to 1:

20. The molar ratio of the acrylamide to the acrylic acid was 1:2 to 2:

1. The molar ratio of the acrylic acid to the N,N-methylenebisacrylamide was 1:5 to 1:

7. The amount of the ruthenium-ethylenediaminetetraacetic acid complex added accounted for 3.6% to 11% of the molar amount of the acrylic acid.

5. An adsorbent prepared using the thermosensitive ruthenium-ethylenediaminetetraacetic acid imprinted polymer obtained by the method described in claim 1.

6. The method for preparing an adsorbent as described in claim 5, characterized in that: This method involves crushing a thermosensitive ruthenium-ethylenediaminetetraacetic acid (EDTA) imprinted polymer, sieving the particles through a 30-120 mesh sieve, placing them in a 500-mesh filter bag, and then eluting the ruthenium-EDTA complex in a Soxhlet extractor using analytical grade anhydrous ethanol as the eluent. The concentration of the corresponding ruthenium-EDTA complex in the etching solution is determined by ICP-AES. Elution is stopped when the measured value is below 0.02 μg / mL. The filter bag is then rinsed alternately with methanol and water until the solution is neutral, and finally vacuum dried to constant weight to obtain the adsorbent.

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