A method for preparing a carbon dot aerogel-like liquid composite containing pentavalent uranium

Abstract

The application discloses a preparation method of carbon dot-like gelatinous liquid composite material containing pentavalent uranium, and belongs to the field of uranium inorganic synthesis. The application aims at solving the problems of high energy consumption and high cost in the prior art. The method is as follows: 1-ethyl-6-fluoro-1,4-dihydro-4-oxo-7-(1-piperazinyl)-3-quinoline carboxylic acid is dispersed in deionized water, and is fully stirred by magnetic force until uniform; then, hydrothermal reaction is carried out, and after the reaction is completed, natural cooling is carried out until room temperature, and filtration is carried out, so that carbon dot colloid is obtained; then, uranyl ions are added dropwise into the prepared high-concentration carbon dot colloid, the color changes from yellow to red brown, the colloid is changed into viscous gelatinous, and carbon dot stable pentavalent uranium composite material is obtained. The method has the advantages of low energy consumption, environmental protection and low cost; meanwhile, the application has large yield, and the material / product has good fluidity, so that continuous production and transportation are facilitated, and the industrial application value is remarkable.

Description

Technical Field

[0001] This invention belongs to the field of uranium inorganic synthesis, specifically, it relates to a method for preparing a carbon dot-like gel-like liquid composite material containing pentavalent uranium. Background Technology

[0002] The electronic configuration of uranium is [Rn]5f. 3 6d 1 7s 2 Uranium can exhibit multiple valence states, including +3, +4, +5, and +6. Both the 5f and 6d orbitals of uranium possess bonding capabilities, causing uranium compounds to often exhibit properties different from transition metals and lanthanides. Pentavalent uranium (U(V)) is generally considered to readily undergo disproportionation reactions in aqueous solutions; therefore, common uranium ions and compounds are predominantly tetravalent and hexavalent. Studies have shown that pentavalent uranium can exist stably and form stable stationary phases in specific microenvironments (such as strongly reducing microbial environments) or specific crystal / coordination structures (such as mineral lattices and metal-organic frameworks). However, the preparation of carbon dot-like gel materials crosslinked with pentavalent uranium is rarely reported. This research is of great significance for enriching our understanding of the chemistry of materials with special valence states of basic actinides and for developing advanced spent fuel reprocessing technologies.

[0003] Existing technology CN111099659A discloses a method for preparing pentavalent uranium and its application. This method involves placing uranium trioxide (U₃O₃) and ammonium chloride in a molten chloride salt, and heating the mixture under conditions of water and oxygen isolation to obtain pentavalent uranium. The reaction temperature is 350℃~800℃. This method requires the isolation of water and oxygen, the heating temperature is relatively high, making it impossible to prepare at room temperature. Furthermore, the molten salt method is costly, and the operating conditions of water and oxygen isolation are quite demanding, which to some extent limits the further research and application of pentavalent uranium materials.

[0004] Existing technology CN113293390A discloses a method, apparatus, and application for the electrochemical reduction preparation of pentavalent uranium in aqueous solution. This method uses a highly conductive material as the anode and a titanium sheet as the cathode in an aqueous solution containing hexavalent uranium. An external voltage is applied via a DC power supply to electrochemically reduce hexavalent uranium to pentavalent uranium, which is then enriched on the cathode surface. The titanium electrode enriched with pentavalent uranium is removed from the solution, dried with nitrogen gas, and the deposited product is scraped off to obtain pentavalent uranium. This method involves relatively expensive titanium metal electrodes and requires an external DC power supply and auxiliary operations such as nitrogen drying, making the process relatively complex.

[0005] Therefore, how to provide a cross-linked carbon dot-based gel material with relatively mild preparation conditions that can stabilize pentavalent uranium is a technical problem that needs to be solved in this field. Summary of the Invention

[0006] This invention addresses the high energy consumption and high cost problems prevalent in existing technologies by providing a method for preparing a carbon dot-like gel-like liquid composite material containing pentavalent uranium. The carbon dot-stabilized pentavalent uranium material prepared using this method features low raw material costs and a simple preparation method. Furthermore, this type of gel-like liquid material can remain stable at room temperature for several months, providing an ideal research medium for studying the optical, magnetic, medical, and catalytic properties of pentavalent uranium. This invention offers significant advantages in terms of mild conditions, low cost, low energy consumption, environmental friendliness, continuous production, large-scale implementation, and product stability, making it more suitable for further research and practical applications of pentavalent uranium materials.

[0007] To address the aforementioned technical problems, the present invention adopts the following technical solution: The purpose of this invention is to provide a method for preparing a carbon dot-like gel-like liquid composite material containing pentavalent uranium, characterized by comprising the following steps: Step 1: Disperse 1-ethyl-6-fluoro-1,4-dihydro-4-oxo-7-(1-piperazinyl)-3-quinolinecarboxylic acid in deionized water and stir magnetically until homogeneous. Step 2: Then, a hydrothermal reaction is carried out. After the reaction is completed, the mixture is naturally cooled to room temperature and filtered to obtain carbon dot colloids. The prepared carbon dots contain nitrogen-containing benzene ring structures. Step 3: Add uranyl ions dropwise to the carbon dot colloid until the color changes, thus obtaining the gel-like liquid composite material.

[0008] Further specifying, in step 1, the mass ratio of 1-ethyl-6-fluoro-1,4-dihydro-4-oxo-7-(1-piperazinyl)-3-quinoline carboxylic acid to deionized water is (0.3-0.5):(20-30); preferably, the mass ratio of 1-ethyl-6-fluoro-1,4-dihydro-4-oxo-7-(1-piperazinyl)-3-quinoline carboxylic acid to deionized water is 0.4:25.

[0009] Further specifying, in step 1, magnetic stirring is performed at a speed of 1000-2000 rpm.

[0010] Further specifying, in step 2, 160 o Hydrothermal reaction at C-200 ℃.

[0011] Furthermore, the hydrothermal reaction is carried out in a high-pressure reactor lined with Teflon and made of stainless steel.

[0012] Further specifying, in step 2, filtration is performed using a 0.22 μm microporous membrane to remove large particulate impurities.

[0013] Further specifying, in step 3, the concentration of uranyl ions is 0.1 mol / L to 0.5 mol / L.

[0014] Further specifying, in step 3, the volume ratio of uranyl ions to carbon dot-like gel liquid is (200-500) μL: (2-5) mL.

[0015] Further specifying, in step 3, the dropping speed is 1d / s-5d / s.

[0016] To further specify, in step 3, the color changes from yellow to reddish-brown, and the colloid transforms into a viscous gel.

[0017] Another object of the present invention is to provide a carbon dot-like gel-like liquid composite material containing pentavalent uranium prepared by any of the above methods.

[0018] Compared with the prior art, the present invention has the following beneficial effects: The preparation conditions of this invention are mild and the operation is simple, avoiding the harsh requirements of high temperature, lava, and strict anhydrous and oxygen-free conditions. This invention does not require the high-temperature reaction of 350℃~800℃ and the chloride molten salt system as described in CN111099659A, nor does it require operation under strict isolation of water and oxygen. The overall preparation conditions are milder and the operation is simpler, which is beneficial to the further research and practical application of pentavalent uranium materials.

[0019] This invention avoids the high energy consumption and complex auxiliary operations of electrolysis. Compared with CN113293390A, which requires titanium cathode, external DC power supply, nitrogen drying and product scraping, this invention does not require high energy consumption electrolysis, nor does it require expensive titanium metal electrodes and complex auxiliary equipment. The process steps are simpler, and the energy consumption and cost are lower.

[0020] This invention uses low-cost, environmentally friendly raw materials and avoids the need for special, expensive organic ligands. It achieves the stabilization and recombination of pentavalent uranium without requiring difficult-to-obtain or expensive special organic ligands, offering advantages of environmental friendliness, low energy consumption, and low cost, thus improving upon the high energy consumption and high cost problems of existing technologies.

[0021] The process of this invention features accurate and continuously controllable formulation, making it suitable for industrial-scale preparation. This invention achieves the industrial-scale preparation of this product by preparing raw materials with 1-ethyl-6-fluoro-1,4-dihydro-4-oxo-7-(1-piperazinyl)-3-quinolinecarboxylic acid and deionized water at a mass ratio of (0.3–0.5):(20–30) and employing a continuous production method. This process is continuously controllable, has high production efficiency, good batch consistency, and is easy to scale up and implement industrially, effectively reducing production costs and improving capacity and product stability.

[0022] This invention offers high yield and flowable products, improving upon the problems of low yield and difficulty in processing. It overcomes the shortcomings of existing methods, such as low yield and limited product morphology, producing samples with high yield and flowability, facilitating subsequent transfer, processing, and application.

[0023] The carbon dot-like gel-like liquid composite material containing pentavalent uranium obtained in this invention exhibits good stability and broad application prospects. The carbon dot-stabilized pentavalent uranium material prepared by this invention features low raw material cost and a simple preparation method. Furthermore, this type of gel-like liquid material can remain stable at room temperature for several months, providing an ideal research platform for studying the optical, magnetic, medical, and catalytic properties of pentavalent uranium.

[0024] For a deeper understanding of the features and technical content of this invention, please refer to the accompanying detailed description and drawings. It should be noted that the drawings are provided for illustrative purposes only and are not intended to limit the scope of the invention. Attached Figure Description

[0025] Figure 1 It is the carbon dot preparation process; Figure 2 Optical image of a stable pentavalent uranium cross-linked carbon dot gel material; Figure 3 These are the UV absorption spectra of uranyl ion aqueous solution and uranyl after adding carbon dots; a) is the UV absorption spectrum of uranyl ion aqueous solution and uranyl after adding carbon dots to 2 mL N-CDs. 2+ The solution gradually changed from yellowish-brown to stable, transparent, deep reddish-brown, which is the ultraviolet absorption spectrum of pentavalent uranium. b) is a magnified view of the absorption spectrum of the reddish-brown sample in the 700-1100 nm range. Figure 4 It is the XPS spectrum of stable pentavalent uranium; Figure 5 When Na, K, Mg, Ca, Ba, Sr, Co, and uranyl ions are added to carbon dot colloids, only the plastic tube containing uranyl ions exhibits a highly viscous gel-like state when inverted; the others remain in a liquid state. The addition of uranyl ions to the carbon dot colloid allows for injection writing and demonstrates good fluidity; other metal ions do not exhibit this phenomenon. Detailed Implementation

[0026] The present invention will be described in detail below with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but should not be considered as limiting the present invention. It should be noted that those skilled in the art can make several modifications and improvements without departing from the concept of the present invention. These all fall within the protection scope of the present invention.

[0027] Example 1: The carbon dot-like gel-like liquid composite material containing pentavalent uranium in this example was prepared according to the following steps: Step 1: Disperse 0.4 g of 1-ethyl-6-fluoro-1,4-dihydro-4-oxo-7-(1-piperazinyl)-3-quinolinecarboxylic acid in 25 mL of deionized water and stir magnetically at 1000 rpm for 20 min to form a uniform milky white suspension. Step 2: The milky white suspension obtained above is transferred to a 50 ml stainless steel autoclave lined with Teflon. The autoclave is then hydrothermally reacted at 200°C for 6 hours, followed by natural cooling to room temperature to obtain a carbon dot colloidal solution. Figure 1 ; Step 3: Filter the obtained carbon dot colloid using a 0.22 μm microporous membrane to remove large particulate impurities and obtain a uniform carbon dot colloid, which is a carbon dot containing a nitrogen-containing benzene ring structure. Step 4: Add 200 μL of uranyl ions with a concentration of 0.1 mol / L to 2 ml of the carbon dot-like gel liquid prepared above at a rate of 2 d / s. The color changes from yellow to transparent reddish-brown, thus obtaining the target product. The generated pentavalent uranium composite material is then subjected to certain tests to confirm the presence of pentavalent uranium.

[0028] Add 200 μL of UO2 to 2 mL of N-CDs 2+ The solution gradually changes from yellowish-brown to a stable, transparent, deep reddish-brown, exhibiting the ultraviolet absorption spectrum of pentavalent uranium (the absorption peak extends to the 800-1100 nm infrared region, attributed to the ff transition of U(V)). See [link to relevant documentation]. Figure 3 a) The color remains stable for several months, and no obvious Tyndall effect was observed after exposure to light, proving it is a homogeneous liquid phase. (See...) Figure 3 b).

[0029] XPS spectrum of stable pentavalent uranium as follows Figure 4 As shown, the high-resolution U₄f XPS has binding energies of 381.2 eV and 391.7 eV, which belong to the peaks of pentavalent uranium.

[0030] The specific embodiments of the present invention have been described in detail above. It should be noted that the present invention is not limited to the specific embodiments described above. Various modifications or alterations can be made by those skilled in the art without departing from the scope of protection defined by the claims, and all such modifications or alterations fall within the scope of the present invention.

Claims

1. A method for preparing a carbon dot-like gel-like liquid composite material containing pentavalent uranium, characterized in that, Includes the following steps: Step 1: Disperse 1-ethyl-6-fluoro-1,4-dihydro-4-oxo-7-(1-piperazinyl)-3-quinolinecarboxylic acid in deionized water and stir magnetically until homogeneous. Step 2: Then, a hydrothermal reaction is carried out. After the reaction is completed, the mixture is allowed to cool naturally to room temperature and then filtered to obtain carbon dot colloids. Step 3: Add uranyl ions dropwise to the carbon dot colloid until the color changes, thus obtaining the gel-like liquid composite material.

2. The method according to claim 1, characterized in that, The mass ratio of 1-ethyl-6-fluoro-1,4-dihydro-4-oxo-7-(1-piperazinyl)-3-quinolinecarboxylic acid to deionized carboxylic acid is (0.3-0.5):(20-30).

3. The method according to claim 1, characterized in that, The mass ratio of 1-ethyl-6-fluoro-1,4-dihydro-4-oxo-7-(1-piperazinyl)-3-quinoline carboxylic acid to deionized water is 0.4:

25.

4. The method according to claim 1, characterized in that, 160 o Hydrothermal reaction at C-200 ℃.

5. The method according to claim 1, characterized in that, Filtered using a 0.22 μm microporous membrane.

6. The method according to claim 1, characterized in that, The concentration of uranyl ions is 0.1-0.5 mol / L.

7. The method according to claim 1, characterized in that, The concentration of uranyl ions is 0.1 mol / L.

8. The method according to claim 1, characterized in that, The volume ratio of uranyl ions to carbon dot-like gel liquid is (200-500) μL: (2-5) mL.

9. The method according to claim 1, characterized in that, Dropping speed: 1 d / s - 5 d / s.

10. A carbon dot-like gel-like liquid composite material containing pentavalent uranium prepared by the method of any one of claims 1-9.

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