Random copolymer for removing molybdenum ions in water as well as preparation method and application of random copolymer
By using random copolymers prepared from tetra-(4-aminobenzene)ethylene and 2,3-dihydroxyterephthaldehyde in a highly acidic environment, the problem of low selective adsorption efficiency of molybdenum ion in the prior art is solved, and efficient and stable molybdenum ion adsorption effect is achieved.
Patent Information
- Application Number
- CN202510226848.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-27
- Publication Date
- 2025-05-30
AI Technical Summary
The existing adsorption separation methods are difficult to achieve selective removal and adsorption of molybdenum ions among a variety of complex ions, especially in high acidic environments, and the adsorption efficiency is not high.
A random copolymer was prepared by radical polymerization, specifically from tetra-(4-aminobenzene)ethylene and 2,3-dihydroxyterephthaldehyde as functional monomers, and synthesized by solution heat under acetic acid catalysis to form a random copolymer with a porous structure and rich imine bonds and hydroxy bonds.
This random copolymer exhibits high selectivity adsorption of molybdenum ions under high acid concentration environment. The adsorption efficiency is higher than 99% at low concentrations. The adsorption amount can reach 117.95 mg/g at high concentrations, and is not affected by acidity and has good acid resistance.
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Figure CN120059101A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of metal ion enrichment and separation, and particularly relates to a material for selectively adsorbing metal ions in geological elements, a preparation method thereof, and an application of adsorbing molybdenum ions. Background Art
[0002] Molybdenum (Mo) is an important transition metal, which is widely used in the steel industry, catalysts, fertilizers, and the electronics industry. Molybdenum is a transition element located in the fifth period and the sixth subgroup of the periodic table. It is an important fission product element, and multiple isotopes of it are at the peak of the light peak of the fission yield double-hump curve, with relatively high fission yields. Molybdenum is a key test object in spent fuel burnup analysis and the fission chemistry research of uranium and plutonium. In the earth's crust, molybdenum mainly exists in the form of molybdate (MoO 4 2- ). Molybdenum ions are essential trace elements for the human body at low concentrations, but excessive amounts can cause toxicity and have a negative impact on the ecosystem and human health. Therefore, the removal and efficient adsorption of molybdenum ions are important research topics. In recent years, extensive research has been carried out on the separation and removal of molybdenum ions, including adsorption separation methods using inorganic materials such as activated carbon, nano metal oxides, and graphene. The adsorption separation method is an economical, environmentally friendly, and effective method for separating metal ions from solutions, and this method is considered to be the most promising method for removing metal ions, with extremely high separation efficiency. However, the existing methods cannot achieve selective removal and adsorption of molybdenum ions among multiple complex ions, and considering the background condition of geological elements, the adsorption process needs to be carried out in a relatively high acidic environment. Therefore, it is necessary to develop an adsorption material that is more stable under acidic conditions and has ideal selectivity to further improve the removal and separation effect of molybdenum ions. Summary of the Invention
[0003] The purpose of the present invention is to provide a random copolymer capable of selectively adsorbing molybdenum ions, and a preparation method for this polymer.
[0004] The random copolymer provided by the present invention is prepared by free radical polymerization of monomer tetra-(4-aminophenyl)ethylene and monomer 2,3-dihydroxyterephthalaldehyde; the arrangement of monomer units in the copolymer is randomly distributed; the copolymer is amorphous, and there are no sharp crystal diffraction peaks in its X-ray diffraction pattern.
[0005] Furthermore, the copolymer of the present invention has a mesoporous structure, its surface area is 80 - 83 m 2 g -1 , and the total pore volume is 0.17 - 0.19 cm 3 g -1 .
[0006] Furthermore, the particle size range of the copolymer of the present invention is between 30±5 nm.
[0007] The preparation method of the above-mentioned random copolymer for removing molybdenum ions from water is as follows: Dissolve tetra-(4-aminophenyl)ethylene and 2,3-dihydroxyterephthalaldehyde in 1,4-dioxane, add an 8-10 mol / L acetic acid aqueous solution and benzoic anhydride, and let it stand and react at 110-130 °C for 60-80 hours under anaerobic conditions. After the reaction, cool to room temperature, filter by suction and wash with anhydrous tetrahydrofuran. The obtained solid is dried at 100-150 °C under dynamic vacuum to obtain the random copolymer.
[0008] In the above preparation method, it is preferred that the molar ratio of tetra-(4-aminophenyl)ethylene to 2,3-dihydroxyterephthalaldehyde is 1:2-3.
[0009] In the above preparation method, it is preferred that the molar ratio of 2,3-dihydroxyterephthalaldehyde to acetic acid is 1:12-15.
[0010] In the above preparation method, it is preferred that the molar ratio of 2,3-dihydroxyterephthalaldehyde to benzoic anhydride is 1:3-4.
[0011] In the above preparation method, it is preferred that the volume ratio of the acetic acid aqueous solution to 1,4-dioxane is 1:5-10.
[0012] In the above preparation method, it is further preferred to let it stand and react at 120 °C for 72 hours under anaerobic conditions.
[0013] The present invention further provides the use of the above-mentioned random copolymer as an adsorbent for removing molybdenum ions from water.
[0014] The beneficial effects of the present invention are as follows:
[0015] The present invention uses acetic acid as a catalyst, benzoic anhydride as an auxiliary agent, tetra-(4-aminophenyl)ethylene and 2,3-dihydroxyterephthalaldehyde as functional monomers, and prepares an organic porous random copolymer by a solvothermal method. The preparation process is simple. The prepared random copolymer has a porous structure, and its surface has abundant imine bonds and hydroxyl bond sites. In a high-concentration acid environment, the imine structure will be protonated, which not only has a unique selective adsorption property for molybdenum ions, but also has an excellent adsorption capacity for molybdenum ions (>99%) at a low concentration (molybdenum ion concentration is 0.6 mg / L). At a high concentration (molybdenum ion concentration is 100 mg / L), the adsorption amount of molybdenum ions can reach up to 117.95 mg / g, which can effectively remove molybdenum ions in geological elements and greatly increase its adsorption efficiency. And it is not affected by acidity during the adsorption process, has good acid resistance, and the adsorption still maintains at a high level under acidic conditions. Especially in high-concentration acid, it still has extremely high removal and selectivity for molybdenum ions. At room temperature (25 °C), the maximum adsorption amount of molybdenum ions can reach 96.625 mg / g in 1 mol / L nitric acid acidity. Through theoretical calculation, it can be obtained that the removal of molybdenum ions is mainly achieved by the formation of hydrogen bonds between the C-H and -OH bonds contained in the random copolymer itself and the O on MoO 4 2- to efficiently adsorb and remove molybdenum ions, which is verified by infrared testing. BRIEF DESCRIPTION OF THE DRAWINGS
[0016] Figure 1 is the infrared spectrum of EDHA prepared in Example 1 before and after adsorbing molybdenum ions.
[0017] Figure 2 is the SEM image of EDHA prepared in Example 1.
[0018] Figure 3 is the TEM image of EDHA prepared in Example 1.
[0019] Figure 4 is the X-ray diffraction pattern of EDHA prepared in Example 1.
[0020] Figure 5 is the pore size distribution diagram of EDHA prepared in Example 1.
[0021] Figure 6 is the nitrogen adsorption and desorption diagram of EDHA prepared in Example 1.
[0022] Figure 7 is the selectivity diagram of EDHA prepared in Example 1 for 15 metal ions under different acidities.
[0023] Figure 8 is the diagram of the change in the adsorption amount of molybdenum ions with the increase in the mass of EDHA.
[0024] Figure 9 It is a graph showing the change in the adsorption ratio of low-concentration molybdenum ions (0.6 mg / L) with the increase in the quality of EDHA.
[0025] Figure 10 It is a graph showing the change in the adsorption amount of EDHA prepared in Example 1 under different nitric acid acidity conditions.
[0026] Figure 11 It is a theoretical calculation graph of the adsorption of molybdenum ions by EDHA prepared in Example 1. Detailed implementation manners
[0027] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments, but the protection scope of the present invention is not limited to these embodiments.
[0028] Example 1
[0029] Preparation of EDHA
[0030] Add 200 mg (0.504 mmol) of tetra-(4-aminophenyl)ethylene (ETTA) and 169 mg (1.02 mmol) of 2,3-dihydroxyterephthalaldehyde (2,3-Dha) into a 50 mL pressure-resistant tube, add 10 mL of 1,4-dioxane, after ultrasonic treatment for 10 minutes, add 692 mg (3.06 mmol) of benzoic anhydride and 1.5 mL of 9 mol / L acetic acid aqueous solution, continue ultrasonic treatment for 10 minutes, then freeze-thaw the pressure-resistant tube three times in liquid nitrogen to fully degas and seal it, and leave it standing in an oven at 120 °C for reaction for 72 hours. A red precipitate is generated at the bottom of the pressure-resistant tube. After the reaction, cool it to room temperature, filter to collect the precipitate and wash it thoroughly three times with tetrahydrofuran, and then dry it thoroughly at 120 °C under dynamic vacuum for 12 hours to obtain 3.4 g of red powder EDHA, with a yield of 92%. Figure 1 It can be observed that the synthesis of EDHA is successful, and the -NH 2 on ETTA and the -CHO in 2,3-Dha form a -CH=N- bond through a random copolymerization condensation reaction. From Figure 2 and Figure 3 , it can be seen that EDHA presents a polyclustered shape, and its particle size range is between 30.44 ± 2.23 nm. From Figure 4 of the X-ray diffraction pattern, there is no sharp crystal diffraction peak, indicating that EDHA is amorphous, and the arrangement of monomer units in its structure is randomly distributed. Through Figure 5 of the pore size distribution diagram and Figure 6 of the nitrogen adsorption and desorption diagram, it can be seen that EDHA is a mesoporous structure, and its surface area is 81.65 m 2 g -1 , and the corresponding total pore volume (P / P0 = 0.99) is 0.18 cm 3 g -1 .
[0031] Example 2
[0032] Preparation of EDHA
[0033] 135 mg (0.34 mmol) of tetra-(4-aminophenyl)ethylene (ETTA) and 169 mg (1.02 mmol) of 2,3-dihydroxyterephthalaldehyde (2,3-Dha) were added into a 50 mL pressure-resistant tube, and 10 mL of 1,4-dioxane was added. After ultrasonic treatment for 10 minutes, 692 mg (3.06 mmol) of benzoic anhydride and 1.5 mL of 9 mol / L acetic acid aqueous solution were added. After continuing ultrasonic treatment for 10 minutes, the pressure-resistant tube was sealed after being degassed by three freeze-thaw cycles in liquid nitrogen. It was left to react in an oven at 130 °C for 60 hours, and a red precipitate was formed at the bottom of the pressure-resistant tube. After the reaction, it was cooled to room temperature, the precipitate was collected by suction filtration and washed thoroughly with tetrahydrofuran three times, and then dried thoroughly under dynamic vacuum at 120 °C for 12 hours to obtain red powder EDHA. The successful synthesis of EDHA was characterized by infrared spectroscopy. There were no sharp crystal diffraction peaks in its X-ray diffraction characterization pattern, indicating that the obtained EDHA was amorphous.
[0034] Example 3
[0035] Preparation of EDHA
[0036] 200 mg (0.504 mmol) of tetra-(4-aminophenyl)ethylene (ETTA) and 169 mg (1.02 mmol) of 2,3-dihydroxyterephthalaldehyde (2,3-Dha) were added into a 50 mL pressure-resistant tube, and 10 mL of 1,4-dioxane was added. After ultrasonic treatment for 10 minutes, 923 mg (4.08 mmol) of benzoic anhydride and 1.5 mL of 9 mol / L acetic acid aqueous solution were added. After continuing ultrasonic treatment for 10 minutes, the pressure-resistant tube was sealed after being degassed by three freeze-thaw cycles in liquid nitrogen. It was left to react in an oven at 110 °C for 80 hours, and a red precipitate was formed at the bottom of the pressure-resistant tube. After the reaction, it was cooled to room temperature, the precipitate was collected by suction filtration and washed thoroughly with tetrahydrofuran three times, and then dried thoroughly under dynamic vacuum at 120 °C for 12 hours to obtain red powder EDHA. The successful synthesis of EDHA was characterized by infrared spectroscopy. There were no sharp crystal diffraction peaks in its X-ray diffraction characterization pattern, indicating that the obtained EDHA was amorphous.
[0037] Example 4
[0038] Application of EDHA in Adsorbing Molybdenum Ions
[0039] The EDHA prepared in Example 1 was used for the selective test of molybdenum ions in water. In this experiment, 17 metal ions in geological elements (Na + , K + , Ca2+ , Mg 2+ , Al 3+ , Fe 3+ , Ti 4+ , Mn 2+ , Nd 3+ , Ce 3+ , Ba 2+ , La 3+ , Mo 6+ , Te 5+ , Sr 2 + , Nb 5+ , Cd 2+ )'s adsorption capacity, different acidities were prepared with nitric acid to explore its selectivity for different metal ions under different acidities. The specific method was as follows: After adjusting the aqueous solution containing the 17 metal ions (the metal ion concentration was 0.6 mg / L) to different acidities with nitric acid, 20 mL was taken and 8 mg of EDHA was added thereto, and it was shaken at 25 °C for 2 h in a constant temperature oscillator. As Figure 7 shown, under the interference of various geological elements, EDHA still had a very high removal rate for molybdenum ions, and the removal rate was the highest at a nitric acid acidity of 1 mol / L, which also met the acidic environment required for dissolving geological soil.
[0040] Further evaluated the adsorption capacity of the EDHA prepared in Example 1 for molybdenum ions. The specific method was as follows: Different masses of EDHA were added to 20 mL of an aqueous molybdenum ion solution with a molybdenum ion concentration of 100 mg / L, and it was shaken at 25 °C for 2 h in a constant temperature oscillator. As Figure 8 visible, when the molybdenum ion concentration was 100 mg / L, when the amount of EDHA added was 8 mg, the adsorption maximum for molybdenum ions reached 96.625 mg / g. At the same time, a removal rate test was carried out at a molybdenum ion concentration of 0.6 mg / L. At room temperature, the mass of EDHA added was gradually increased to 20 mL of the aqueous molybdenum ion solution. After ICP-OES testing, it was found that the amount of remaining molybdenum ions in the aqueous solution gradually decreased, indicating that EDHA had excellent removal performance for molybdenum ions, and the adsorption removal rate > 99% (see Figure 9 ). In order to better show that EDHA still had a good adsorption amount for molybdenum ions in an acidic environment, different acidities were prepared to test its specific adsorption amount. The specific method was as follows: After adjusting 20 mL of an aqueous molybdenum ion solution with a molybdenum ion concentration of 100 mg / L to different acidities with nitric acid, 20 mL was taken and 8 mg of EDHA was added thereto, and it was shaken at 25 °C for 2 h in a constant temperature oscillator. As Figure 10 visible, under high molybdenum ion concentration (molybdenum ion concentration of 100 mg / L) and 1 mol / L acidic conditions, the adsorption amount of EDHA for molybdenum ions could reach up to 117.95 mg / g at most, which could be attributed to the deprotonation of -OH under acidic conditions. At the same time, asFigure 1 The infrared spectra before and after adsorption indicate that the adsorption is carried out by C-H and -OH.
[0041] In addition, the synthesis energy and adsorption energy of EDHA prepared in the above Example 1 were explored. As Figure 11 shown, through theoretical calculations, it is found that the formation process of EDHA requires energy input, and it has very good adsorption performance for molybdenum ions, with very low binding energies for various binding modes. The extremely high adsorption capacity for molybdenum ions under high acidity conditions is unprecedented, indicating that EDHA still has good stability under acidic conditions.
[0042] In summary, the random copolymer of the present invention has good adsorption performance and stability for molybdenum ions under different acidity conditions and cation competition. The molybdenum ion removal rate and adsorption capacity reach the maximum values at an acidity of 1 mol / L.
Claims
1. A random copolymer for removing platinum ions from water, characterized in that: The copolymer is prepared by free radical polymerization of tetrakis-(4-aminophenyl)ethylene and 2,3-dihydroxyterephthalaldehyde; the monomer units in the copolymer are randomly distributed; the copolymer is amorphous, and its X-ray diffraction spectrum has no sharp crystal diffraction peaks.
2. The random copolymer for removing platinum ions from water according to claim 1, characterized in that: The copolymer has a mesoporous structure and a surface area of 80 to 83 m 2 g -1 , the total pore volume is 0.17~0.19cm 3 g -1 .
3. The random copolymer for removing platinum ions from water according to claim 1, characterized in that: The particle size of the copolymer is in the range of 30±5 nm.
4. A method for preparing a random copolymer for removing platinum ions in water according to claim 1, characterized in that: Tetrakis-(4-aminophenyl)ethylene and 2,3-dihydroxyterephthalaldehyde are dissolved in 1,4-dioxane, and 8-10 mol / L acetic acid aqueous solution and benzoic anhydride are added, and the mixture is allowed to stand at 110-130° C. for 60-80 hours under anaerobic conditions. After the reaction is completed, the mixture is cooled to room temperature, filtered and washed with anhydrous tetrahydrofuran, and the obtained solid is dried at 100-150° C. under dynamic vacuum to obtain the random copolymer.
5. The method for preparing a random copolymer for removing platinum ions in water according to claim 4, characterized in that: The molar ratio of tetrakis-(4-aminophenyl)ethylene to 2,3-dihydroxyterephthalaldehyde is 1:2-3.
6. The method for preparing a random copolymer for removing platinum ions from water according to claim 4, characterized in that: The molar ratio of the 2,3-dihydroxyterephthalaldehyde to the acetic acid is 1:12-15.
7. The method for preparing a random copolymer for removing platinum ions from water according to claim 4, characterized in that: The molar ratio of the 2,3-dihydroxyterephthalaldehyde to benzoic anhydride is 1:3-4.
8. The method for preparing a random copolymer for removing platinum ions from water according to claim 4, characterized in that: The volume ratio of the acetic acid aqueous solution to 1,4-dioxane is 1:5-10.
9. The method for preparing a random copolymer for removing platinum ions from water according to claim 4, characterized in that: The reaction was allowed to stand at 120°C under anaerobic conditions for 72 hours.
10. Use of the random copolymer according to claim 1 as an adsorbent for removing platinum ions in water.