A uranium-thorium specific capture agent in a complex solution system, its synthesis method and application

Abstract

A uranium-thorium specific capture agent in a complex solution system. The uranium-thorium specific capture agent is a modified cellulose material containing multiple phosphate groups, and its molecular structure is: #imgabs0#.

Description

Technical Field

[0001] The present invention belongs to the field of heavy metal wastewater treatment, and particularly relates to a uranium-thorium specific capture agent in a complex solution system, a synthesis method and application thereof. Background Art

[0002] Uranium and thorium are widely present in the Earth's crust. They are important associated metals of tantalum and niobium ores and are common heavy metals in wastewater from mining and metallurgical industries. They are radioactive and difficult to treat, making them one of the most harmful pollutants to the environment and the human body. Because uranium and thorium cannot be decomposed and destroyed, the current treatment method is to separate them from the wastewater through phase transfer. Among the currently developed uranium and thorium wastewater treatment methods, such as traditional chemical precipitation, chelation adsorption, iron reduction, ion exchange, ion flotation, membrane separation, electrochemical methods, adsorption, and biological methods, all have certain shortcomings: for example, they easily adsorb large amounts of harmless ions such as iron and aluminum ions, and cannot be washed off and reused. Summary of the Invention

[0003] In order to solve the above problems, the purpose of the present invention is to solve the defects and shortcomings of the existing technology and provide a polymer material with both specific capture and flocculation functions.

[0004] A uranium-thorium specific capture agent in a complex solution system, wherein the uranium-thorium specific capture agent is a modified cellulose material containing multiple phosphate groups, and its molecular structure is: .

[0005] A method for synthesizing a uranium-thorium specific capture agent in a complex solution system:

[0006] S1: First, take the cellulose product and dry it at 100-120℃ to constant weight and chop it into small pieces. Then, add the above-mentioned pieces into an anhydrous solvent and then add the calculated amount of organic base. Stir at room temperature for 30 minutes to make it evenly distributed.

[0007] S2: slowly add an appropriate amount of chlorophosphate at 20-30°C, and keep the temperature for reaction after adding the chlorophosphate;

[0008] S3: After the reaction is completed, the solvent is removed by filtration, and the obtained modified cellulose product is added into water, stirred and washed, filtered again, and dried at 70-90°C to obtain the product.

[0009] The reaction equation of the cellulose product and the organic base is as follows:

[0010] .

[0011] Preferably, the cellulose product is a mixture of one or more of absorbent cotton, filter paper, cotton cloth or other recycled paper.

[0012] Preferably, the reaction solvent is one of tetrahydrofuran, chloroform, dichloromethane or diethyl ether.

[0013] Preferably, the organic base is a mixture of one or more of triethylamine, pyridine, DBU, and DMAP, and the usage ratio of the organic base to the cellulose product is:

[0014] Organic alkali: cellulose product = 1.5-3:1, calculated by mass.

[0015] Preferably, the ratio of the amount of cellulose product to the amount of solvent is 4-8 L per kilogram of cellulose.

[0016] Preferably, the chlorophosphate ester is one of dimethyl chlorophosphate, diethyl chlorophosphate, dipropyl chlorophosphate, and dibutyl chlorophosphate.

[0017] Preferably, the usage ratio of the chlorophosphate ester and the cellulose product is: chlorophosphate ester: cellulose product = 2.7-6.4:1, calculated in parts by mass, and the addition time is 1-5 hours.

[0018] Preferably, the reaction time of the insulation reaction is 1-5 hours, and the reaction temperature is 25-60°C.

[0019] A method for the specific adsorption of uranium and thorium in complex solution systems involving the coexistence of multiple ions. Compared to the aforementioned methods, the chelation flocculation adsorption method offers advantages such as simplicity, high efficiency, and cost-effectiveness. It does not adsorb abundant, harmless ions such as iron and aluminum ions, can be eluted, and can be reused repeatedly, making it suitable for large-scale treatment of complex uranium- and thorium-containing wastewater systems. The key to this approach lies in the groups and backbone structure used.

[0020] Beneficial Effects: The present invention achieves specific adsorption of uranium and thorium in complex solution systems with multiple ions coexisting, eliminating interference from common, harmless ions such as iron and aluminum that easily bind to chelating agents. It specifically enriches and recovers uranium and thorium in complex systems. After treatment, the uranium and thorium concentration in wastewater can be reduced to less than 1 mg / L. This effectively enhances flocculation and capture of uranium and thorium without interference from foreign ions, significantly reduces the amount of radioactive residue, and improves the treatment of wastewater with excessive uranium and thorium levels. DETAILED DESCRIPTION

[0021] The present invention will be further described below with reference to the embodiments.

[0022] This scheme is to modify natural cellulose with diethyl chlorophosphate in a weakly alkaline environment to obtain a modified cellulose material containing a large number of phosphate groups. This modified cellulose material can achieve specific adsorption of uranium and thorium, eliminate interference from common harmless ions such as iron and aluminum that are easily combined with chelating agents, and specifically enrich and recover uranium and thorium elements in complex systems. Example

[0023] A uranium-thorium-containing wastewater, in which the uranium content is 563 mg / L, thorium is 20 mg / L, iron is 9300 mg / L, aluminum is 1600 mg / L, and pH is 1.

[0024] Steps: Dry absorbent cotton at 105°C to constant weight, then chop it into small pieces. Weigh 20g and add it to 100mL of tetrahydrofuran with stirring. Add 38.05g of pyridine and stir at room temperature for 30 minutes. Then, dropwise add 70.23g of diethyl chlorophosphate over 2 hours. After the addition is complete, react at 60°C for 4 hours. Filter, disperse the solid in 100mL of water, stir at room temperature for 30 minutes, filter, and dry at 80°C to obtain the product.

[0025] The following three samples were used to compare the corresponding experimental parameters:

[0026] (1) Stock solution: Take 500 ml of the above-mentioned uranium-thorium wastewater, without adding any reactants or treating it, and measure the heavy metal content in the clear solution.

[0027] (2) Take 500 mL of the above-mentioned uranium-thorium wastewater, add solid sodium hydroxide to adjust the pH to 2, add 1 g of the above-mentioned product, stir and react for 10 minutes, filter, and take the clear liquid to measure the uranium and thorium content.

[0028] (3) Take 500 mL of the above-mentioned uranium-thorium wastewater, add solid sodium hydroxide to adjust the pH to 2, add 2 g of the above-mentioned product, stir and react for 10 minutes, filter, and measure the uranium and thorium content of the clear liquid. The relevant water quality test results are shown in Table 1:

[0029] Table 1 Water sample test results (unit: mg / L)

[0030]

[0031] Obviously, the above embodiments of the present invention are merely examples for the purpose of illustrating the present invention and are not intended to limit the implementation of the present invention. Those skilled in the art will appreciate that other variations or modifications can be made based on the above description. It is not necessary and impossible to provide an exhaustive list of implementations. However, obvious variations or modifications arising from the essence of the present invention remain within the scope of protection of the present invention.

Claims

1. A method for synthesizing a uranium-thorium specific capture agent in a complex solution system, characterized by: S1: First, take a cellulose product and dry it at 100-120°C to constant weight and chop it into pieces. The above-mentioned pieces are added to an anhydrous solvent and then a calculated amount of organic base is added. The mixture is stirred at room temperature for 30 minutes to ensure uniform distribution. The cellulose product is a mixture of one or more of absorbent cotton, filter paper, cotton cloth or other recycled paper; the organic base is a mixture of one or more of triethylamine, pyridine, DBU, and DMAP. The ratio of the organic base to the cellulose product is: organic base: cellulose product = 1.5-3:1, calculated by weight; S2: slowly adding an appropriate amount of chlorophosphate at 20-30° C., wherein the chlorophosphate is one of dimethyl chlorophosphate, diethyl chlorophosphate, dipropyl chlorophosphate, and dibutyl chlorophosphate, and keeping the temperature for reaction after adding the chlorophosphate; S3: After the reaction is completed, the solvent is removed by filtration, and the obtained modified cellulose product is added into water, stirred and washed, filtered again and dried at 70-90°C to obtain the product. The uranium-thorium specific capture agent is used for the specific adsorption of uranium and thorium in a complex solution system of pH=2 where multiple ions coexist.

2. The method for synthesizing a uranium-thorium specific capture agent in a complex solution system according to claim 1, characterized in that: The reaction solvent is one of tetrahydrofuran, chloroform, dichloromethane or ether.

3. The method for synthesizing a uranium-thorium specific capture agent in a complex solution system according to claim 1, characterized in that: The ratio of the amount of the cellulose product to the amount of the solvent is 4-8 L per kilogram of cellulose.

4. The method for synthesizing a uranium-thorium specific capture agent in a complex solution system according to claim 1, characterized in that: The dosage ratio of the chlorophosphate ester and the cellulose product is: chlorophosphate ester: cellulose product = 2.7-6.4:1, calculated in parts by mass, and the addition time is 1-5 hours.

5. The method for synthesizing a uranium-thorium specific capture agent in a complex solution system according to claim 1, characterized in that: The reaction time of the heat preservation reaction is 1-5 hours, and the reaction temperature is 25-60°C.

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