A method for adsorbing uranyl ions in seawater

Abstract

The present invention belongs to the technical field of uranyl ion treatment, and specifically relates to a method for adsorbing uranyl ions in seawater. The present invention adopts an exchange system to adsorb uranyl ions in seawater; the exchange system comprises a seawater area, a buffer zone and an adsorption zone arranged in sequence; the seawater area and the buffer zone are separated by an anion exchange membrane, and the buffer zone and the adsorption zone are separated by a cation exchange membrane; the adsorption zone and the seawater area are connected by a reverse osmosis pump; the buffer zone comprises a buffer solution; and the adsorption zone comprises a uranyl ion adsorption material. The present invention comprises an anion and cation exchange membrane, a buffer zone, an adsorption zone and other parts to form an exchange system, and the synergistic effect of each part makes the exchange system have excellent adsorption performance, high adsorption efficiency, simple assembly and convenient operation.

Description

Technical Field

[0001] The invention belongs to the technical field of uranyl ion treatment, and in particular relates to a method for adsorbing uranyl ions in seawater. Background Art

[0002] There are abundant uranium resources in seawater, with a huge total amount, far exceeding the uranium reserves on land. Compared with traditional underground uranium mining, uranium extraction from seawater avoids large-scale mining and causes less damage to the environment; therefore, there are many methods for extracting uranium from seawater. The main methods for extracting uranium from seawater include membrane separation, ion exchange, adsorption, etc.

[0003] The ion exchange method has good selectivity and large adsorption capacity, but the cost of ion exchange resin is relatively high and the chemical stability of the resin is poor, so care must be taken during use.

[0004] The membrane separation method can efficiently separate and enrich uranyl ions in seawater, improve the recovery rate, and the separation process is relatively fast; however, as the separation process continues, the concentration difference of the solution on both sides of the membrane gradually decreases, which can easily lead to reduced efficiency.

[0005] The adsorption method has become one of the most studied methods due to its high extraction rate, simple operation, and a wide variety of adsorption materials. For example, the Chinese patent with the announcement number CN116196900B discloses a method for preparing an anti-fouling seawater uranium extraction material. The patent sequentially prepares an epoxy-modified substrate, an amino-modified substrate, a single-layer polyamide-amine modified substrate, a multi-layer polyamide-amine modified substrate (cycled 1 to 4 times), and CP-PAMAM2-6-FI, and finally obtains AO / CP-PAMAM2-6-FI (anti-fouling seawater uranium extraction material). The adsorption capacity of the obtained anti-fouling seawater uranium extraction material is 1-2 times that of conventional seawater uranium extraction fiber, and it also has anti-fouling properties. However, this method has many reaction steps and the preparation method is relatively complicated.

[0006] Therefore, it is particularly important to develop a highly selective and low-cost method for adsorbing uranyl ions in seawater. Summary of the invention

[0007] The existing method for adsorbing uranyl ions from seawater has the problems of low selectivity and high cost. In order to solve the problem, the present invention provides a method for adsorbing uranyl ions from seawater.

[0008] In order to achieve the purpose of the present invention, the present invention adopts the following technical solutions:

[0009] The present invention provides a method for adsorbing uranyl ions in seawater, which uses an exchange system to adsorb uranyl ions in seawater; the exchange system comprises a seawater area, a buffer area and an adsorption area which are arranged in sequence; the seawater area and the buffer area are separated by an anion exchange membrane, and the buffer area and the adsorption area are separated by a cation exchange membrane; the adsorption area and the seawater area are connected by a reverse osmosis pump;

[0010] The buffer zone includes a buffer solution; and the adsorption zone includes a uranyl ion adsorption material.

[0011] Preferably, the preparation method of the buffer is as follows:

[0012] The potassium hydrogen phthalate aqueous solution and the hydrochloric acid aqueous solution are mixed and stirred continuously to obtain a buffer solution.

[0013] Preferably, the pH of the buffer solution is 5-6, and the stirring time is 20-30 min.

[0014] Preferably, the preparation method of the uranyl ion adsorption material is as follows:

[0015] Mix zirconium phosphate and sodium hydroxide solution uniformly to obtain liquid A; add water to liquid A and adjust the pH to 6-7 to obtain liquid B; slowly add ethyl orthosilicate to liquid B, react at 45-50° C. for 30-50 minutes, add auxiliary components and mix uniformly at 35-40° C. to obtain uranyl ion adsorption material;

[0016] Among them, by mass ratio, liquid A: water = 1: 5-10; by mass ratio, liquid B: ethyl orthosilicate = 1: 50-100.

[0017] Preferably, the auxiliary components include the following components, in parts by mass:

[0018] 0.05-0.08 parts of sodium pyrophosphate, 0.001-0.003 parts of cinnamaldehyde, 0.002-0.004 parts of oxalic acid, and 0.001-0.002 parts of alkylphenol polyoxyethylene ether.

[0019] Preferably, the total mass of the auxiliary components accounts for 2%-3.2% of the mass of the zirconium phosphate.

[0020] Preferably, the preparation method of the cation exchange membrane is as follows:

[0021] The sulfonated chitosan and 2.5%-3% PVA aqueous solution are mixed uniformly in a mass ratio of 1:20-35 to obtain a mixed solution, 45-60 parts by mass of tetraethyl orthosilicate are added to the mixed solution, stirred at 45-50°C, spread after 25-30 minutes, cast on a glass plate, dried at room temperature for 3-4 hours, and washed with alcohol to obtain a cation exchange membrane.

[0022] Preferably, the sulfonated chitosan is prepared by sulfonating chitosan using concentrated sulfuric acid as a sulfonating agent and isopropanol as a solvent.

[0023] Preferably, the preparation method of the anion exchange membrane is as follows:

[0024] The brominated polyphenylene ether and chloroform are mixed evenly at a mass ratio of 1:100-500 at 45-50°C, and palygorskite and stearic acid monoglyceride are added and mixed evenly to obtain a mixed solution, the mixed solution is vacuumed and poured into a clean glass dish, and cured at room temperature, and after the film is formed, it is washed with water and dried to obtain a composite film;

[0025] The composite membrane is immersed in a trimethylamine aqueous solution for 8-10 hours for quaternization treatment, and then transferred to a sodium hydroxide aqueous solution for further immersion for 2-3 hours, and washed with water and dried to obtain an anion exchange membrane;

[0026] The mass of the palygorskite is 2%-4% of the mass of the brominated polyphenylene ether, and the mass of the stearic acid monoglyceride is 0.3%-0.4% of the mass of the brominated polyphenylene ether.

[0027] Preferably, the seawater area is provided with a sand filter, and the bottom of the adsorption area is provided with a high-mesh filter, and the high-mesh filter is a 500-600 mesh filter.

[0028] Specifically: the exchange system is driven by the pressure of the reverse osmosis pump. The seawater is filtered through a sand filter to remove solid microparticle impurities, and then passes through the anion exchange membrane under pressure. The system operating pressure is 2.3-3.5Mpa, and the filter pore size is 1-3nm; after passing through the anion exchange membrane, it enters the buffer zone. The pH of the buffer solution is maintained at 5.0-6.5. In natural seawater, uranyl ions are usually in the form of uranyl carbonate UO 2 (CO 3 ) 3 4− Form exists, UO 2 (CO 3 ) 3 4− Remove the ligand in the buffer, leaving the UO 2 2+ , see reaction equation (1); containing UO 2 2+Driven by the pressure difference, the seawater can still maintain a filtration pressure of 0.5-1.2Mpa when passing through the buffer solution and passes through the cation exchange membrane. The pore size of the cation exchange membrane is 2-5nm. The seawater treated by the exchange membrane twice reaches the adsorption area (uranyl ion adsorption material), where the uranyl ions are adsorbed and react with the uranyl ion adsorption material to form a chelate product, see reaction equation (2); the seawater after the adsorption of uranyl ions is filtered through a high-mesh filter, and the seawater passes through a reverse osmosis pump with a suction power of 7KW-25KW, and flows back to the seawater area to complete the circulation process.

[0029] (1)

[0031] (2)

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] (1) The present invention uses an exchange system to block the impurity ions in seawater through two layers of ion exchange membranes, while the uranyl ions can pass through the membranes to reach the adsorption area. The zirconium phosphate is dispersed in the adsorption area and has a large contact area with the uranyl ions that pass through the membrane. The zirconium phosphate can combine with the uranyl ions to form a complex product to achieve an adsorption effect, thereby improving the problem that the traditional zirconium phosphate-based adsorption material has low selectivity for uranyl ions;

[0035] (2) The auxiliary component sodium pyrophosphate in the adsorption zone of the present invention can further form a chelate with the uranyl cation. The compact epoxy structure in the chelate structure shields the uranyl cation, and works together with the weakly polar organic small molecules cinnamaldehyde and oxalic acid to achieve a shielding effect on the uranyl ions in the adsorption zone, thereby reducing the influence of uranyl enrichment in the adsorption zone on the concentration difference driving ability, effectively improving the problem that the adsorption efficiency decreases with the concentration difference on both sides of the membrane, and reducing energy consumption;

[0036] (3) The present invention comprises an anion and cation exchange membrane, a buffer zone, an adsorption zone and other parts to form an exchange system. The synergistic effect of these parts makes the exchange system have excellent adsorption performance and high adsorption efficiency, and is simple to assemble and easy to operate. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 Schematic diagram of the exchange system of the present invention; wherein A is the seawater area, B is the buffer area, C is the adsorption area, and D is the reverse osmosis pump;

[0038] Figure 2 This is a competitive adsorption diagram of the uranyl ion adsorption material for each ion in Test Example 1 of the present invention. DETAILED DESCRIPTION

[0039] The technical solution of the present invention is explained in detail below with reference to several representative embodiments and drawings of the present invention.

[0040] The experimental methods used in the following examples are conventional methods unless otherwise specified. The materials, reagents, etc. used in the following examples are all commercially available unless otherwise specified.

[0041] A method for adsorbing uranyl ions in seawater, using an exchange system to adsorb uranyl ions in seawater; the exchange system is shown in Figure 1 The exchange system comprises a seawater zone, a buffer zone and an adsorption zone which are arranged in sequence; the seawater zone and the buffer zone are separated by an anion exchange membrane, and the buffer zone and the adsorption zone are separated by a cation exchange membrane; the adsorption zone and the seawater zone are connected by a reverse osmosis pump; a sand filter is provided in the seawater zone, and a high-mesh filter is provided at the bottom of the adsorption zone.

[0042] The buffer zone includes a buffer solution; and the adsorption zone includes a uranyl ion adsorption material.

[0043] Example 1

[0044] (1) Preparation of buffer

[0045] Mix 0.2 mol / L potassium hydrogen phthalate aqueous solution and 0.2 mol / L hydrochloric acid aqueous solution, adjust the pH to 5, and stir continuously to obtain a buffer solution;

[0046] (2) Preparation of uranyl ion adsorption materials

[0047] 2.85g of zirconium phosphate crystals and 25mL of 0.75mol / L NaOH aqueous solution were mixed uniformly to obtain liquid A; 10 times the mass of water was added to liquid A, and the pH was adjusted to 7 to obtain liquid B; 70 times the mass of ethyl orthosilicate was slowly added to liquid B, and the mixture was stirred continuously at 45°C for 50min, and 0.05g of sodium pyrophosphate, 0.002g of cinnamaldehyde, 0.003g of oxalic acid, and 0.002g of alkylphenol polyoxyethylene ether were added and mixed uniformly at 37°C to obtain a uranyl ion adsorption material;

[0048] (3) Preparation of the cation exchange membrane

[0049] Dissolve 1.5g chitosan in 22.5g isopropanol, then slowly add 5mL 75% concentrated sulfuric acid, stir in an ice-salt bath for 3h, precipitate the product with anhydrous ethanol, centrifuge and wash twice with alcohol, dissolve in water, adjust pH, desalt and concentrate, and dry at 65℃ for 7h to obtain sulfonated chitosan;

[0050] Sulfonated chitosan and 2.5% PVA aqueous solution were mixed in a mass ratio of 1:20 to obtain a mixed solution, 60 parts by mass of tetraethyl orthosilicate was added to the mixed solution, stirred at 48°C, spread after 25 minutes, cast on a glass plate, dried at room temperature for 3 hours, the film thickness was 0.35 mm, and washed with alcohol to obtain a cation exchange membrane;

[0051] (4) The preparation method of the anion exchange membrane is as follows:

[0052] 0.59 g of brominated polyphenylene ether and 59 g of chloroform were mixed at 50°C, and then 0.0118 g of palygorskite and 0.0023 g of stearic acid monoglyceride were added and mixed to obtain a mixed solution. The mixed solution was vacuumed and poured into a clean glass dish, and cured at room temperature to obtain a film thickness of 0.3 mm. After the film was formed, it was washed with water and dried at 50°C for 12 hours to obtain a composite film.

[0053] The composite membrane was immersed in a 35% trimethylamine aqueous solution for 8 hours for quaternization treatment, and then transferred to a 1 mol / L sodium hydroxide aqueous solution for further immersion for 3 hours. After washing and drying, an anion exchange membrane was obtained.

[0054] (5) Exchange system

[0055] The exchange system is driven by the pressure of the reverse osmosis pump. The seawater is filtered through a sand filter to remove solid microparticle impurities, and then passes through the anion exchange membrane under pressure. The system operating pressure is 2.3Mpa, and the filter pore size is 2nm; after passing through the anion exchange membrane, it enters the buffer zone. The pH of the buffer solution is maintained at 5.5, UO 2 (CO 3 ) 3 4− Remove the ligand in the buffer, leaving the UO 2 2+ ; Contains UO 2 2+ Driven by the pressure difference, the seawater maintains a filtration pressure of 1Mpa and passes through the cation exchange membrane. The pore size of the cation exchange membrane is 2nm. The seawater treated by the exchange membrane twice reaches the adsorption area (uranyl ion adsorption material), where the uranyl ions are adsorbed and react with the uranyl ion adsorption material to form a chelate product; the seawater after the adsorption of uranyl ions is filtered through a 550-mesh filter, and the seawater passes through a reverse osmosis pump with a suction power of 7KW and flows back to the seawater area to complete the circulation process.

[0056] Example 2

[0057] (1) Preparation of buffer

[0058] Mix 0.2 mol / L potassium hydrogen phthalate aqueous solution and 0.2 mol / L hydrochloric acid aqueous solution, adjust the pH to 5.6, and stir continuously to obtain a buffer solution;

[0059] (2) Preparation of uranyl ion adsorption materials

[0060] 2.85g of zirconium phosphate crystals and 25mL of 0.75mol / L NaOH aqueous solution were mixed uniformly to obtain liquid A; 8 times the mass of water was added to liquid A, and the pH was adjusted to 6 to obtain liquid B; 50 times the mass of ethyl orthosilicate was slowly added to liquid B, and the mixture was stirred continuously at 48°C for 30min, and 0.08g of sodium pyrophosphate, 0.003g of cinnamaldehyde, 0.004g of oxalic acid, and 0.001g of alkylphenol polyoxyethylene ether were added and mixed uniformly at 35°C to obtain a uranyl ion adsorption material;

[0061] (3) Preparation of the cation exchange membrane

[0062] Dissolve 1.5g chitosan in 37.5g isopropanol, then slowly add 5mL 75% concentrated sulfuric acid, stir in an ice-salt bath for 3h, precipitate the product with anhydrous ethanol, centrifuge and wash twice with alcohol, dissolve in water, adjust pH, desalt and concentrate, and dry at 70℃ for 8h to obtain sulfonated chitosan;

[0063] The sulfonated chitosan and the 3% PVA aqueous solution were mixed in a mass ratio of 1:35 to obtain a mixed solution, 50 parts by mass of tetraethyl orthosilicate was added to the mixed solution, stirred at 45°C, spread after 30 minutes, cast on a glass plate, dried at room temperature for 4 hours, the film thickness was 0.33 mm, and washed with alcohol to obtain a cation exchange membrane;

[0064] (4) The preparation method of the anion exchange membrane is as follows:

[0065] 0.59 g of brominated polyphenylene ether and 177 g of chloroform were mixed at 45°C, and then 0.0177 g of palygorskite and 0.0018 g of stearic acid monoglyceride were added and mixed to obtain a mixed solution. The mixed solution was vacuumed and poured into a clean glass dish, and cured at room temperature to obtain a film thickness of 0.2 mm. After the film was formed, it was washed with water and dried at 60°C for 12 hours to obtain a composite film.

[0066] The composite membrane was immersed in a 35% trimethylamine aqueous solution for 10 h for quaternization treatment, and then transferred to a 1 mol / L sodium hydroxide aqueous solution for further immersion for 2 h. After washing and drying, an anion exchange membrane was obtained.

[0067] (5) Exchange system

[0068] The exchange system is driven by the reverse osmosis pump pressure. The seawater is filtered through a sand filter to remove solid microparticle impurities, and then passes through an anion exchange membrane under pressure. The system operating pressure is 3.5Mpa, and the filter pore size is 1nm; after passing through the anion exchange membrane, it enters the buffer zone. The pH of the buffer solution is maintained at 6.5, UO 2 (CO 3 )3 4− Remove the ligand in the buffer, leaving the UO 2 2+ ; Contains UO 2 2+ Driven by the pressure difference, the seawater maintains a filtration pressure of 0.5Mpa and passes through the cation exchange membrane. The pore size of the cation exchange membrane is 3nm. The seawater treated by the exchange membrane twice reaches the adsorption area (uranyl ion adsorption material), where the uranyl ions are adsorbed and react with the uranyl ion adsorption material to form a chelate product. The seawater after the adsorption of uranyl ions is filtered through a 600-mesh filter, and the seawater passes through a reverse osmosis pump with a suction power of 25KW and flows back to the seawater area to complete the circulation process.

[0069] Example 3

[0070] (1) Preparation of buffer

[0071] Mix 0.2 mol / L potassium hydrogen phthalate aqueous solution and 0.2 mol / L hydrochloric acid aqueous solution, adjust the pH to 6, and stir continuously to obtain a buffer solution;

[0072] (2) Preparation of uranyl ion adsorption materials

[0073] 2.85g zirconium phosphate crystals were mixed with 25mL 0.75mol / L NaOH aqueous solution to obtain liquid A; 5 times the mass of water was added to liquid A, and the pH was adjusted to 6 to obtain liquid B; 100 times the mass of ethyl orthosilicate was slowly added to liquid B, and the mixture was stirred continuously at 50°C for 40min, and 0.07g sodium pyrophosphate, 0.001g cinnamaldehyde, 0.002g oxalic acid, and 0.001g alkylphenol polyoxyethylene ether were added and mixed uniformly at 35°C to obtain a uranyl ion adsorption material;

[0074] (3) Preparation of the cation exchange membrane

[0075] Dissolve 1.5g chitosan in 30g isopropanol, then slowly add 5mL 75% concentrated sulfuric acid, stir in an ice-salt bath for 3h, precipitate the product with anhydrous ethanol, centrifuge and wash twice with alcohol, dissolve in water, adjust pH, desalt and concentrate, and dry at 70℃ for 7h to obtain sulfonated chitosan;

[0076] Sulfonated chitosan and 3% PVA aqueous solution were mixed in a mass ratio of 1:25 to obtain a mixed solution, 45 parts by mass of tetraethyl orthosilicate was added to the mixed solution, stirred at 50°C, spread after 25 minutes, cast on a glass plate, dried at room temperature for 3.5 hours, the film thickness was 0.3 mm, and washed with alcohol to obtain a cation exchange membrane;

[0077] (4) The preparation method of the anion exchange membrane is as follows:

[0078] 0.59 g of brominated polyphenylene ether and 295 g of chloroform were mixed evenly at 50° C., and then 0.0236 g of palygorskite and 0.0023 g of stearic acid monoglyceride were added and mixed evenly to obtain a mixed solution. The mixed solution was vacuumed and poured into a clean glass dish, and cured at room temperature to obtain a film thickness of 0.35 mm. After the film was formed, it was washed with water and dried at 65° C. for 12 h to obtain a composite film.

[0079] The composite membrane was immersed in a 35% trimethylamine aqueous solution for 10 h for quaternization treatment, and then transferred to a 1 mol / L sodium hydroxide aqueous solution for further immersion for 3 h. After washing and drying, an anion exchange membrane was obtained.

[0080] (5) Exchange system

[0081] The exchange system is driven by the pressure of the reverse osmosis pump. The seawater is filtered through a sand filter to remove solid microparticle impurities, and then passes through the anion exchange membrane under pressure. The system operating pressure is 3Mpa, and the filter pore size is 3nm; after passing through the anion exchange membrane, it enters the buffer zone. The pH of the buffer solution is maintained at 6, UO 2 (CO 3 ) 3 4− Remove the ligand in the buffer, leaving the UO 2 2+ ; Contains UO 2 2+ Driven by the pressure difference, the seawater maintains a filtration pressure of 1.2Mpa and passes through the cation exchange membrane. The pore size of the cation exchange membrane is 5nm. The seawater treated by the exchange membrane twice reaches the adsorption area (uranyl ion adsorption material), where the uranyl ions are adsorbed and react with the uranyl ion adsorption material to form a chelate product. The seawater after the adsorption of uranyl ions is filtered through a 500-mesh filter, and the seawater passes through a reverse osmosis pump with a suction power of 15KW and flows back to the seawater area to complete the circulation process.

[0082] Taking the materials and exchange system prepared in Example 1 as an example, a simulated seawater experiment test was carried out

[0083] The adsorption capacity of the exchange system for uranium was investigated in seawater spiked with various ions (U, V, Co, Fe, Ni, Mn, Zn, Cu), where the concentrations of uranium and other metal ions were approximately 100 times the actual values ​​of ion concentrations in natural seawater, as shown in Table 1.

[0084] The concentrations of uranyl ions and other ions within time t were measured by ICP-OES inductively coupled plasma optical emission spectrometry, and the adsorption capacity and removal rate were calculated as follows:

[0085] ;

[0086] ;

[0087] Among them, Q t Indicates the amount of ions extracted in time t, mg / g; C 0 Indicates the initial ion concentration, mg / L; C t It represents the concentration of ions at time t, mg / L; V represents the volume of the test seawater, L; m represents the mass of the adsorbent, g; R represents the ion removal rate within time t, %.

[0088] Table 1 Ion concentration in seawater

[0089]

[0090] Test Example 1

[0091] The concentrations of uranyl ions and other ions before and after adsorption by the uranyl ion adsorbent material were measured by ICP-OES inductively coupled plasma optical emission spectrometry. The results are shown in Table 2.

[0092] Specifically: 1L seawater, 48h, 30mg uranyl ion adsorption material, initial seawater temperature 25±2℃, initial pH value 8.3±0.2.

[0093] Table 2 Ion concentration

[0094]

[0095] As shown in Table 1, the adsorption capacity of uranyl ion by uranyl ion adsorption material is 9.36 mg / g, which has certain selectivity. However, V ions still interfere with the adsorption of uranyl ions. The competitive adsorption diagram of uranyl ion adsorption material for various ions is shown in Figure 2 .

[0096] Test Example 2

[0097] The concentrations of uranyl ions and other ions before and after the exchange system (without adding uranyl ion adsorption material) were determined by ICP-OES inductively coupled plasma optical emission spectrometry; the solutions flowing from the initial seawater area and the final adsorption area to the seawater area were taken as test solutions for ion concentrations before and after adsorption, the same below; the results are shown in Table 3.

[0098] Specific: 1L seawater, initial seawater temperature 25±2℃, initial pH value 8.3±0.2.

[0099] Table 3 Ion concentration

[0100]

[0101] As shown in Table 3, the presence of anion and cation exchange membranes and buffer in the exchange system blocks other ions outside the adsorption zone, thus reducing the interference of other ions on uranyl ions to a certain extent.

[0102] Test Example 3

[0103] The concentrations of uranyl ions and other ions before and after adsorption by the exchange system were measured by ICP-OES inductively coupled plasma optical emission spectrometry. The results are shown in Table 4.

[0104] Specifically: 1L seawater, 48h circulation, 30mg uranyl ion adsorption material, initial seawater temperature 25±2℃, initial pH value 8.3±0.2.

[0105] Table 4 Ion concentration

[0106]

[0107] The experimental results show that after 48 hours of circulation, the adsorption capacity of uranyl ions by the exchange system is 10.83 mg / g.

[0108] Test Example 4

[0109] The concentration of uranyl ions before and after adsorption by the exchange system was measured by ICP-OES inductively coupled plasma optical emission spectrometry. The results are shown in Table 5.

[0110] Table 5 Uranyl ion adsorption

[0111]

[0112] Test Example 5

[0113] The concentration of uranyl ions before and after the exchange system prepared in Test Example 5 (the difference between Test Example 5 and Example 1 is that the uranyl ion adsorption material does not contain auxiliary components, and the rest is the same as Example 1) was measured by ICP-OES inductively coupled plasma optical emission spectrometer. The results are shown in Table 6.

[0114] Specifically: 1L seawater, 48h circulation, 30mg uranyl ion adsorption material (without auxiliary components), initial seawater temperature 25±2℃, initial pH value 8.3±0.2.

[0115] Table 6 Uranyl ion adsorption

[0116]

[0117] It can be seen from Table 6 that the presence of auxiliary components allows more uranyl ions to pass through the membrane per unit time, thereby increasing the amount of uranyl ions adsorbed in the adsorption area.

[0118] The above is an exemplary description of the present invention. It should be noted that, without departing from the core of the present invention, any simple deformation, modification or equivalent replacement that can be done by other technicians in this field without expending creative labor falls within the protection scope of the present invention.

Claims

1. A method for adsorbing uranyl ions in seawater, characterized in that: An exchange system is used to adsorb uranyl ions in seawater; the exchange system comprises a seawater zone, a buffer zone and an adsorption zone arranged in sequence; the seawater zone and the buffer zone are separated by an anion exchange membrane, and the buffer zone and the adsorption zone are separated by a cation exchange membrane; the adsorption zone and the seawater zone are connected by a reverse osmosis pump; The buffer zone includes a buffer solution; the adsorption zone includes a uranyl ion adsorption material; The preparation method of the buffer solution is as follows: Mixing an aqueous potassium hydrogen phthalate solution and an aqueous hydrochloric acid solution, and stirring continuously to obtain a buffer solution; The pH of the buffer solution is 5-6, and the stirring time is 20-30 min; The preparation method of the uranyl ion adsorption material is as follows: Mix zirconium phosphate and sodium hydroxide solution uniformly to obtain liquid A; add water to liquid A and adjust the pH to 6-7 to obtain liquid B; slowly add ethyl orthosilicate to liquid B, react at 45-50° C. for 30-50 minutes, add auxiliary components and mix uniformly at 35-40° C. to obtain uranyl ion adsorption material; Among them, by mass ratio, liquid A: water = 1: 5-10; by mass ratio, liquid B: ethyl orthosilicate = 1: 50-100; The auxiliary components include the following components, in parts by mass: Sodium pyrophosphate 0.05-0.08 parts, cinnamaldehyde 0.001-0.003 parts, oxalic acid 0.002-0.004 parts, alkylphenol polyoxyethylene ether 0.001-0.002 parts; The total mass of the auxiliary components accounts for 2%-3.2% of the mass of the zirconium phosphate.

2. The method for adsorbing uranyl ions in seawater according to claim 1, characterized in that: The preparation method of the cation exchange membrane is as follows: The sulfonated chitosan and the PVA aqueous solution with a mass fraction of 2.5%-3% are mixed uniformly in a mass ratio of 1:20-35 to obtain a mixed solution, 45-60 parts by mass of tetraethyl orthosilicate are added to the mixed solution, stirred at 45-50°C, spread after 25-30 minutes, cast on a glass plate, dried at room temperature for 3-4 hours, and washed with alcohol to obtain a cation exchange membrane.

3. The method for adsorbing uranyl ions in seawater according to claim 2, characterized in that: The sulfonated chitosan is prepared by sulfonating chitosan using concentrated sulfuric acid as a sulfonating agent and isopropanol as a solvent.

4. The method for adsorbing uranyl ions in seawater according to claim 1, characterized in that: The preparation method of the anion exchange membrane is as follows: The brominated polyphenylene ether and chloroform are mixed evenly at a mass ratio of 1:100-500 at 45-50°C, and palygorskite and stearic acid monoglyceride are added and mixed evenly to obtain a mixed solution, the mixed solution is vacuumed and poured into a clean glass dish, and cured at room temperature, and after the film is formed, it is washed with water and dried to obtain a composite film; The composite membrane is immersed in a trimethylamine aqueous solution for 8-10 hours for quaternization treatment, and then transferred to a sodium hydroxide aqueous solution for further immersion for 2-3 hours, and washed with water and dried to obtain an anion exchange membrane; The mass of the palygorskite is 2%-4% of the mass of the brominated polyphenylene ether, and the mass of the stearic acid monoglyceride is 0.3%-0.4% of the mass of the brominated polyphenylene ether.

5. The method for adsorbing uranyl ions in seawater according to claim 1, characterized in that: The seawater area is provided with a sand filter, and the bottom of the adsorption area is provided with a high-mesh filter, and the high-mesh filter is a 500-600 mesh filter.

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