Bi-crosslinked network zwitterionic polyamidoxime hydrogel seawater uranium adsorption material with rapid ion transmission function and preparation method of bi-crosslinked network zwitterionic polyamidoxime hydrogel seawater uranium adsorption material

Abstract

The invention discloses a preparation method of a bi-crosslinked network zwitterionic polyamidoxime hydrogel seawater uranium adsorption material with rapid ion transport, which comprises the following steps: uniformly mixing a nanogel dispersion liquid, a polyamidoxime alkaline solution and a zwitterionic compound to obtain a precursor solution, and heating and gelating the precursor solution to obtain PSBMA / PGP hydrogel. According to the method disclosed by the invention, nanogel is used as a cross-linking point, so that the zwitterionic polymer and the polyamidoxime in a specific proportion further form a double-cross-linked hydrogel network through a cross-linking effect, and interconnected through holes and a relatively strong hydration effect are achieved; the diffusion rate of uranyl carbonate ions in the hydrogel is improved while the uranium extraction performance of the polyamidoxime-based gel is not influenced, so that the material has relatively fast uranium adsorption kinetics and anti-biological adhesion effects in a seawater environment.

Description

Technical Field

[0001] The invention relates to the field of polymer functional materials, and in particular to a zwitterionic polyamidoxime hydrogel seawater uranium adsorption material with a double cross-linked network and rapid ion transmission and a preparation method thereof. Background Art

[0002] As an efficient and low-carbon form of energy, nuclear energy has significant advantages such as high energy density and low carbon emissions, and occupies an important position in the global energy structure. Uranium is a key fuel for the operation of nuclear power plants. However, the proven uranium reserves on land are relatively limited. At the current rate of mining and consumption, it is expected to be exhausted in the next few decades to a hundred years. Therefore, the development of new sources of uranium resources is of vital importance to ensure the long-term stable supply of nuclear energy. Seawater contains extremely rich uranium resources, with a total amount estimated to be about 4.5 billion tons, which is equivalent to thousands of times the proven uranium reserves on land. Although the concentration of uranium in seawater is extremely low, usually only 3 micrograms per liter, the huge total amount of seawater makes seawater uranium extraction have broad application prospects.

[0003] At present, the research on uranium extraction from seawater mainly focuses on the adsorption method, that is, the selective adsorption of uranium in seawater by materials with specific adsorption properties. In the early stage, inorganic adsorbents were mainly studied. Later, it was gradually discovered that polymer functional materials modified with amidoxime groups have advantages in uranium adsorption performance, selectivity and mechanical strength, and have become one of the more ideal materials for uranium extraction from seawater. The methods for synthesizing amidoxime-based materials are also constantly developing, including polymer microspheres based on amidoxime, amidoxime-based fibers prepared by chemical routes, amidoxime-based fibers prepared by radiation grafting routes, electrospinning, air blowing spinning, etc. Amidoxime-based materials have a special chemical structure, and their amidoxime groups can undergo specific complexation with uranyl ions, thereby achieving selective adsorption of uranium. This selective adsorption ability makes amidoxime-based materials have a high application value in uranium extraction from seawater, and can effectively separate and enrich uranium in complex seawater environments.

[0004] Although amidoxime-based hydrogel materials have made some progress in the field of uranium extraction from seawater, the traditional three-dimensional porous PAO hydrogel adsorbent locks a large number of water molecules due to strong hydrogen bonding, which is not conducive to the efficient diffusion of water and uranyl carbonate ions inside, thereby weakening the adsorption kinetics process and limiting its industrial application in the field of uranium extraction from seawater. Therefore, it is necessary to develop a hydrogel adsorbent with fast ion transport and excellent uranium adsorption kinetics, which is of great significance for promoting the industrial application of amidoxime-based materials in uranium extraction from seawater. Summary of the invention

[0005] In view of this, the present invention provides a method for preparing a double cross-linked network zwitterionic polyamidoxime hydrogel seawater uranium adsorption material to solve the problem of poor adsorption kinetics of existing amidoxime-based hydrogels.

[0006] On one hand, the present invention adopts a preparation method of a double cross-linked network zwitterionic polyamidoxime hydrogel seawater uranium adsorption material with rapid ion transmission, comprising the following steps: firstly obtaining a polyamidoxime sodium hydroxide precursor solution and a nanogel dispersion according to a certain ratio, then adding 3-[N,N-dimethyl-[2-(2-methylprop-2-enoyloxy)ethyl]ammonium]propane-1-sulfonate, then adding a certain mass of potassium persulfate, fully stirring and transferring to a culture dish, heating for gelation to obtain a formed gel, and obtaining a PSBMA / PGP hydrogel after soaking and washing with deionized water, wherein the input mass ratio of the 3-[N,N-dimethyl-[2-(2-methylprop-2-enoyloxy)ethyl]ammonium]propane-1-sulfonate to the polyamidoxime is 0.25:1.

[0007] Preferably, the dosage of the nanogel dispersion is 1.2 mL, the concentration is 25 mg / mL, and the concentration of the polyamidooxime sodium hydroxide solution is 50 mg / mL.

[0008] Preferably, the mass ratio of 3-[N,N-dimethyl-[2-(2-methylprop-2-enoyloxy)ethyl]ammonium]propane-1-sulfonate to potassium persulfate is 100:1.

[0009] Preferably, the gelation heating temperature is 60° C. and the time is 2 h.

[0010] The preparation method of the double cross-linked network zwitterionic polyamidoxime hydrogel seawater uranium adsorption material with rapid ion transmission provided by the present invention has a simple synthesis process, is environmentally friendly, and is economical and efficient. Nanogels are used as cross-linking points to further form a double cross-linked hydrogel network with interconnected through holes and a strong hydration effect by cross-linking a certain proportion of zwitterionic polymers and polyamidoximes. The network has interconnected through holes and a strong hydration effect, and the diffusion rate of uranyl carbonate ions in the hydrogel is increased without affecting the uranium extraction performance of the polyamidoxime-based gel, so that the material has faster uranium adsorption kinetics and anti-biological adhesion effects in a seawater environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 The infrared spectrum of the zwitterionic polyamidoxime hydrogel (PSBMA / PGP) prepared in Example 1;

[0012] Figure 2 This is a scanning electron microscope morphology image of the zwitterionic polyamidoxime hydrogel (PSBMA / PGP) prepared in Example 1;

[0013] Figure 3 This is the Raman spectrum of the zwitterionic polyamidoxime hydrogel (PSBMA / PGP) prepared in Example 1;

[0014] Figure 4 The adsorption test results of zwitterionic polyamidoxime hydrogel (PSBMA / PGP) prepared in Example 1 under simulated seawater with different uranium concentrations;

[0015] Figure 5 This is a graph showing the anti-adhesion results of the zwitterionic polyamidoxime hydrogel (PSBMA / PGP) prepared in Example 1. DETAILED DESCRIPTION

[0016] The principles and features of the present invention are described below in conjunction with the accompanying drawings. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0017] Embodiment 1: A double cross-linked network zwitterionic polyamidoximine hydrogel seawater uranium adsorption material with rapid ion transport and a preparation method thereof, comprising the following steps:

[0018] Preparation of S101 amidoximated polyacrylonitrile (PAO)

[0019] Add 12g of hydroxylamine hydrochloride to a flask containing 100mL of NN dimethylformamide, heat to 45°C, stir magnetically until completely dissolved, then add 6.9g of sodium hydroxide, stir for at least 3h, then add 10g of polyacrylonitrile powder, fully dissolve for 1h, heat to 80°C and react for 12h. After the reaction is completed, cool and centrifuge at 10000rpm / min for 30min. Take the supernatant, which is the amidoximated polyacrylonitrile solution. Drop the solution into deionized water to obtain a white precipitate, and finally dry in vacuum at 60°C to obtain amidoximated polyacrylonitrile powder.

[0020] Preparation of S102 polyamidoxime alkaline solution

[0021] 100 mg of amidoxime polyacrylonitrile powder was completely dissolved in 2 mL of 0.15 mol / L sodium hydroxide solution, and heated to completely dissolve to obtain a polyamidoxime sodium hydroxide solution with a concentration of 50 mg / mL.

[0022] Preparation of S103 Nanogel (PG) Dispersion

[0023] At room temperature, 100 mg of polyamidoximine powder was weighed and dissolved in 4 mL of 0.15 mol / L sodium hydroxide solution, and then 50 μL of glutaraldehyde and 25 mg of sodium dodecyl sulfate were added to the solution in sequence. After stirring at 50° C. for 1.5 h, a nanogel dispersion with a concentration of 25 mg / mL was obtained.

[0024] Preparation of S104 PSBMA / PGP hydrogel

[0025] 1.2 mL of PG nanogel dispersion was added to the polyamidoxime alkaline solution of S102 and heated for 20 min. After being fully dissolved, 25 mg of 3-[N,N-dimethyl-[2-(2-methylprop-2-enoyloxy)ethyl]ammonium]propane-1-sulfonate (SBMA) was added, and 0.25 mg of potassium persulfate was added according to the mass ratio of SBMA to potassium persulfate of 100:1. The gel precursor solution was transferred to a culture dish and then heated in an oven at 60 ° C for 2 h for gelation. Finally, the newly prepared PSBMA / PGP hydrogel was immersed in deionized water for 24 h to remove the residue to obtain PSBMA / PGP hydrogel.

[0026] Example 2: The difference between Example 2 and Example 1 is that the mass of SBMA added in step S104 is 100 mg, 75 mg, 50 mg, and 0 mg, respectively, that is, the mass ratios of SBMA and PAO used are 1:1, 0.75:1, 0.5:1, and 0:1, respectively, and uranium adsorption test is carried out at room temperature (25°C), 1L, 8ppm uranium spiked simulated seawater (pH=8). It can be seen from the results in Table 1 that the addition of a specific proportion of zwitterionic compounds increases the diffusion rate of uranyl carbonate ions in the hydrogel without affecting the uranium extraction performance of the polyamidoximine-based gel, thereby enabling the material to have faster uranium adsorption kinetics in a seawater environment.

[0027] Table 1 Effect of different SBMA qualities on the properties of PSBMA / PGP hydrogel

[0028]

[0029] Example 3: The PSBMA / PGP hydrogel prepared in Example 1 was characterized and its performance tested, and the results were as follows:

[0030] (1) PSBMA / PGP hydrogel was characterized by infrared spectroscopy. Figure 1 The results show that Figure 1 As shown, the C≡N (2242 cm -1 ) peak disappears, and C=N(1648cm -1 )、CN(1383cm -1 ) and NO(931cm -1 ), which proves the success of amidoximation. PSBMA / PGP at 2970cm -1 The characteristic NH peak is shown at 1042 cm -1 is the stretching vibration peak of S=O, and PSBMA / PGP is at 3460cm -1There is an obvious OH peak at , indicating that both nanogel and PSBMA / PGP hydrogel have been successfully synthesized.

[0031] (2) The PSBMA / PGP hydrogel of Example 1 was tested by scanning electron microscopy. Figure 2 The scanning electron micrographs showed that the PSBMA / PGP hydrogel had a cross-linked network structure, indicating that the hydrogel had interconnected through-holes, which provided an effective channel for the diffusion of uranyl carbonate ions inside the hydrogel.

[0032] (3) Raman spectroscopy test was performed on the PSBMA / PGP hydrogel of Example 1. Figure 3 As shown, Raman spectroscopy is used to detect the structure of the hydration layer. Each Raman spectrum shows a broad OH stretching peak between 3000-3700 cm-1, which is related to the water molecules in the hydration layer. The data are fitted with Gaussian peaks. The ordered water molecules correspond to the region A1, while the disordered water molecules correspond to the region A2. The area ratio of the two regions (A1 / A2) can be used as a measure of the structure of the hydration layer around a given hydrogel. Higher values ​​correspond to higher degrees of hydration. The results show that PSBMA / PGP hydrogel (A1 / A2=0.561) has a stronger hydration effect than PGP (A1 / A2=0.362).

[0033] (4) The PSBMA / PGP hydrogel of Example 1 was subjected to adsorption tests of different uranium concentrations. 5 mg of the hydrogel was placed in 1 L of uranium-spiked simulated seawater at room temperature (25° C.) and pH=8 for testing. The uranium concentrations were set to 4 ppm, 8 ppm, 16 ppm, and 32 ppm, respectively. Figure 4 As shown in the results, in the adsorption process of the hydrogel of Example 1 on simulated seawater with different uranium concentrations, the adsorption equilibrium time was basically 10 h, and the adsorption amount was 173.66 mg g -1 , 274.14 mg g -1 , 696.08mg g -1 , 850.2mg g -1 , showing that PSBMA / PGP hydrogel has higher uranium adsorption capacity and faster ion adsorption capacity at different uranium concentrations.

[0034] (5) The anti-adhesion characterization of the PSBMA / PGP hydrogel of Example 1 was performed. The results are as follows Figure 5 As shown, PSBMA / PGP hydrogel has excellent anti-adhesion effect on Escherichia coli and Staphylococcus aureus compared with PGP.

[0035] In summary, the preparation method of the double cross-linked network zwitterionic polyamidoxime hydrogel seawater uranium adsorption material with rapid ion transport provided by the present invention is simple in synthesis process, environmentally friendly, economical and efficient. A certain proportion of zwitterionic polymers and polyamidoxime are further formed into a double cross-linked hydrogel network by cross-linking using nanogels as cross-linking points. It is found that adding a specific proportion of zwitterionic compounds increases the diffusion rate of uranyl carbonate ions inside the hydrogel without affecting the uranium extraction performance of the polyamidoxime-based gel, thereby enabling the material to have faster uranium adsorption kinetics and anti-biological adhesion effects in a seawater environment.

[0036] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for preparing a double cross-linked network zwitterionic polyamidoximine hydrogel seawater uranium adsorption material with rapid ion transport, characterized in that: The following steps are involved: First, a polyamidoxime sodium hydroxide precursor solution and a nanogel dispersion are obtained according to a certain ratio, and then 3-[N,N-dimethyl-[2-(2-methylprop-2-enoyloxy)ethyl]ammonium]propane-1-sulfonate and potassium persulfate are added, fully stirred and evenly transferred to a culture dish, heated for gelation to obtain a formed gel, and then soaked and washed with deionized water to obtain a PSBMA / PGP hydrogel, wherein the input mass ratio of the 3-[N,N-dimethyl-[2-(2-methylprop-2-enoyloxy)ethyl]ammonium]propane-1-sulfonate to the polyamidoxime is 0.25:

1.

2. The method for preparing a double cross-linked network zwitterionic polyamidoximine hydrogel seawater uranium adsorption material according to claim 1, characterized in that: The dosage of the nanogel dispersion is 1.2 mL, the concentration is 25 mg / mL, and the concentration of the polyamidoximine sodium hydroxide solution is 50 mg / mL.

3. The method for preparing a double cross-linked network zwitterionic polyamidoximine hydrogel seawater uranium adsorption material according to claim 1, characterized in that: The mass ratio of the 3-[N,N-dimethyl-[2-(2-methylprop-2-enoyloxy)ethyl]ammonium]propane-1-sulfonate to potassium persulfate is 100:

1.

4. The method for preparing a double cross-linked network zwitterionic polyamidoximine hydrogel seawater uranium adsorption material according to claim 1, characterized in that: The gelation heating temperature was 60°C and the time was 2 h.

5. A double cross-linked network zwitterionic polyamidoximine hydrogel seawater uranium adsorption material prepared according to the method described in any one of claims 1 to 4.

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