Disclosure of Invention
In view of the above, an object of the present invention is to provide a method for preparing a uranium adsorption resin, which has a good tolerance to acid and phosphorus, can selectively adsorb uranium, and has a good adsorption effect. Another object of the present invention is to provide a uranium adsorption resin prepared according to the preparation method described above. It is a further object of the present invention to provide the use of a uranium adsorbent resin. The invention realizes the aim through the following technical scheme.
In one aspect, the invention provides a method for preparing uranium adsorption resin, comprising the following steps:
(1) Mixing 100-150 parts by weight of chlorinated styrene, 9.5-15 parts by weight of divinylbenzene and 1.2-2.0 parts by weight of an initiator, and then mixing with 11-20 parts by weight of C5-C9 alkane to obtain an organic phase, mixing the organic phase with 500-700 parts by weight of a dispersing agent solution, and reacting for 7-12 hours at 60-90 ℃ to obtain a polymerization product;
(2) Swelling a polymerization product, adding 50-80 parts by weight of ethylenediamine or trimethylamine, and reacting for 12-18 hours at 60-80 ℃ to obtain an amination product;
(3) Mixing the aminated product with 300-500 parts by weight of aldehyde-containing solution, 300-400 parts by weight of phosphite ester and 80-150 parts by weight of acid catalyst, and reacting for 12-24 hours at 80-95 ℃ to obtain the uranium adsorption resin.
In the step (1), after uniformly mixing the chlorinated styrene, the divinylbenzene, the initiator, the C5-C9 alkane and the aqueous solution containing the dispersing agent, suspension polymerization reaction is carried out to obtain a polymerization product.
In the present invention, the amount of the chlorinated styrene may be 100 to 150 parts by weight, preferably 110 to 130 parts by weight. The amount of divinylbenzene may be 9.5 to 15 parts by weight, preferably 10 to 12 parts by weight. The initiator may be used in an amount of 1.2 to 2.0 parts by weight, preferably 1.4 to 1.8 parts by weight.
The amount of C5-C9 alkane may be 11 to 20 parts by weight, preferably 13 to 15 parts by weight. The invention discovers that the proportion of the alkane of C5-C9 has important influence on the pore structure of the polymerization product, the alkane of C5-C9 can be added to carry out pore canal design in the process of synthesizing the polymerization product, the macroporous polymerization product can be obtained, and the subsequent amination reaction and the synthesis of the resin with the amino phosphite ester group are more facilitated.
The dispersant solution may be used in an amount of 500 to 700 parts by weight, preferably 550 to 650 parts by weight.
In step (1), the reaction temperature may be 60 to 90 ℃, preferably 70 to 80 ℃. The reaction time may be 7 to 12 hours, preferably 10 to 12 hours. The polymerization reaction is carried out with stirring. The stirring speed can be 100-200 r/min, and is preferably 130-150 r/min.
After the reaction is finished, the reaction product is filtered, washed and dried to obtain a polymerization product. The filtration may be carried out by filtration means conventional in the art. Alternatively, methanol and tap water may be used for washing. The drying temperature can be 40-60 ℃.
According to the preparation method of the present invention, preferably, the chlorinated styrene is p-chlorostyrene.
According to the preparation method, the initiator is preferably selected from one of benzoyl peroxide, azodiisobutyronitrile and lauroyl peroxide, more preferably the initiator is benzoyl peroxide, the dispersing agent solution contains 0.1-1wt% of dispersing agent, more preferably the dispersing agent contains 0.4-0.6wt% of dispersing agent, the dispersing agent is selected from one of polyvinyl alcohol, oxidized polyvinyl alcohol and polymaleic acid, and more preferably the dispersing agent is polyvinyl alcohol.
According to the preparation process of the present invention, preferably, the C5-C9 alkane is a mixture of linear and branched alkanes. The weight ratio of linear alkane to branched alkane in the mixture may be 1:1 to 3, preferably 1:1. According to the preparation method of the present invention, preferably, the linear alkane is one or more of n-pentane, n-hexane, n-heptane and n-octane, and more preferably, the linear alkane is n-hexane or n-heptane. The branched alkane is selected from one or more of branched alkanes with methyl, dimethyl or trimethyl groups, more preferably the branched alkane is selected from branched alkanes with methyl groups, which may be 2-methylpentane, 2-methylhexane or 2-methylheptane, according to a specific embodiment of the invention the branched alkane is 2-methylheptane.
In the step (2), the pH value of the system is regulated to be more than 9 after the polymerization product is swelled, and then the amination reaction is carried out with ethylenediamine or trimethylamine, so as to obtain an amination product. The invention discovers that the amination reagent in the amination reaction has great influence on the adsorption capacity due to different reactivity and the number of bonded amino groups, and in the invention, the amination reagent can be ethylenediamine or trimethylamine, preferably ethylenediamine, so that the amination reaction is more favorable to be carried out, and the adsorption capacity of the resin is improved. The swelling agent may be one or more of toluene, dichloroethane, carbon tetrachloride, tetrahydrofuran, preferably toluene or carbon tetrachloride, more preferably toluene. The swelling agent may be used in an amount of 120 to 200 parts by weight, preferably 140 to 160 parts by weight. The swelling time may be 30 to 60 minutes, preferably 40 to 50 minutes. The amount of ethylenediamine or trimethylamine may be 50 to 80 parts by weight, 60 to 70 parts by weight. The temperature of the amination reaction may be 60 to 80 ℃, preferably 60 to 70 ℃. The reaction time may be 12 to 18 hours, preferably 12 to 14 hours.
After the reaction is finished, the reaction product is filtered, washed and dried to obtain an aminated product. The filtration may be carried out by filtration means conventional in the art. The aqueous solution can be washed to neutrality by using dilute hydrochloric acid and water.
In the step (3), the amination product is mixed and reacted with aldehyde-containing solution, phosphite ester and acid catalyst to obtain uranium adsorption resin. The invention discovers that the phosphite ester can be directly synthesized into the amino phosphite ester by a one-step method through introducing an acid catalyst, so that the traditional multi-step synthesis is avoided, and the reaction process is simplified.
The aldehyde-containing solution may be used in an amount of 300 to 500 parts by weight, preferably 400 to 480 parts by weight. The phosphite may be used in an amount of 300 to 400 parts by weight, preferably 300 to 350 parts by weight, and the acid catalyst may be used in an amount of 80 to 150 parts by weight, preferably 100 to 120 parts by weight.
In step (3), the reaction temperature may be 80 to 95 ℃, preferably 85 to 90 ℃. The reaction time may be 12 to 24 hours, preferably 14 to 16 hours. The synthesis of the phosphoramidate is more facilitated under the above-mentioned dosage and reaction conditions.
According to the preparation method of the present invention, preferably, the phosphite is selected from dialkyl phosphites, and the alkyl group in the dialkyl phosphites has 1 to 5 carbon atoms. The alkyl group can be an alkyl group, and the alkyl group can be one or more of methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, n-pentyl and isopentyl, preferably one or more of methyl, ethyl, n-propyl and n-butyl. According to the preparation method of the invention, preferably, the alkyl in the dialkyl phosphite is selected from linear alkyl with 1-3 carbon atoms, and the linear alkyl can be methyl, ethyl or n-propyl, preferably ethyl.
According to the preparation method of the present invention, preferably, the aldehyde in the aldehyde-containing solution is selected from one of formaldehyde, acetaldehyde and propionaldehyde. In certain embodiments, the aldehyde is formaldehyde, and in other embodiments, the aldehyde is acetaldehyde. The acidic catalyst is selected from citric acid or hydrochloric acid, more preferably concentrated hydrochloric acid.
On the other hand, the invention also provides the uranium adsorption resin prepared by the preparation method, which has better tolerance to acid and phosphorus, can selectively adsorb uranium, has good adsorption effect, and has the adsorption quantity of more than 40 mg/g. Preferably, the adsorption quantity of uranium by the uranium adsorption resin is 50-61.6 mg/g.
In a further aspect, the invention also provides the use of a uranium adsorption resin according to the above described uranium in adsorbing acidic phosphorus-containing uranium-containing wastewater. The concentration of hydrogen ions in the acidic uranium-containing phosphorus-containing wastewater is 0.2-2.0 mol/L, and the concentration of phosphate radical is not higher than 45g/L.
According to the invention, phosphite ester is utilized to react with p-chloropolystyrene-divinylbenzene copolymer with amino under an acidic condition to obtain uranium adsorption resin, which has good tolerance to acid and phosphorus and good adsorption effect to uranium in acidic phosphorus-containing uranium-containing wastewater. The adsorption quantity of uranium by the uranium adsorption resin is more than 40 mg/g.
Detailed Description
The present invention will be further described with reference to the following specific embodiments, but the scope of the present invention is not limited thereto.
The test method is described as follows:
infrared spectroscopic analysis
Analysis was performed using a fourier transform infrared absorption spectrometer model TENSOR II manufactured by bruke, germany.
Adsorption performance test of uranium
And (3) placing the uranium adsorption resin in acidic uranium-bearing phosphorus wastewater (solid-liquid ratio is 1:200) for adsorption test. The different acidic uranium-bearing phosphate waste water is obtained by diluting stock solution, wherein the stock solution is from a certain uranium-bearing phosphorite land immersion liquid in Guizhou, the phosphate radical concentration is 40-50 g/L, the sulfate radical concentration is 20-30 g/L, the uranium concentration is 100-150 mg/L, and the H + concentration is 2.8-3.6 mol/L. Wherein the hydrogen ion concentration and the phosphate concentration are adjusted by adding phosphoric acid, sulfuric acid and sodium phosphate. The adsorption temperature is 15-40 ℃ and the adsorption time is 6-10 h. After adsorption, the supernatant was analyzed for uranium ion concentration. Uranium ion concentrations were tested as specified by HJ 840-2017.
The uranium adsorption capacity is calculated as follows:
Adsorption capacity = (V 1 x initial uranium ion concentration-V 2 x concentration of uranium ions in adsorption tail liquid)/mass of adsorption resin.
Wherein V 1 is the volume of acidic phosphorus-containing uranium-containing wastewater, the unit is mL, and V 2 is the volume of adsorption tail liquid, the unit is mL. The uranium ion concentration unit is g/L. The mass unit of the adsorption resin is g.
Example 1
1.5G of benzoyl peroxide and 120g of p-chlorostyrene are mixed, 10.5g of divinylbenzene, 6.5g of 2-methylheptane and 6.5g of n-hexane are then added to obtain an organic phase, 600ml of 0.6wt% aqueous polyvinyl alcohol solution are mixed with the organic phase and reacted for 10 hours at a temperature of 80 ℃ and a stirring speed of 155r/min to obtain a reaction product, and the reaction product is filtered, washed alternately with methanol/water and dried at 50 ℃ to obtain a polymerization product.
116G of the polymerization product, 150g of toluene and 65g of ethylenediamine were mixed and reacted at 65℃for 12 hours to obtain an aminated product.
160G of an amination product, 450g of formaldehyde solution, 300g of diethyl phosphite and 100ml of concentrated hydrochloric acid are mixed and reacted for 15 hours at 85 ℃, the solid is filtered out, and the uranium adsorption resin is obtained by washing with water until the mixture is neutral.
Comparative example 1
1.0G of benzoyl peroxide and 90g of p-chlorostyrene are mixed, 9g of divinylbenzene, 7.5g of 2-methylheptane and 2.5g of n-hexane are then added to obtain an organic phase, the organic phase is mixed with 400ml of 0.5wt% polyvinyl alcohol aqueous solution and reacted for 10 hours at a temperature of 75 ℃ and a stirring speed of 120r/min to obtain a reaction product, the reaction product is filtered, methanol/water is alternately washed, and the reaction product is dried at 50 ℃ to obtain a polymerization product.
80G of the polymerization product, 100g of methylene chloride and 40g of hexamethylenetetramine are mixed, the pH value of the system is adjusted to 9 by using NaOH solution, and then the mixture is reacted for 12 hours at 50 ℃ to obtain an amination product.
120G of an amination product, 200g of formaldehyde solution, 250g of diisoamyl phosphite and 50g of citric acid are mixed and reacted for 15 hours at 85 ℃, the solid is filtered out, and the uranium adsorption resin is obtained by washing with water until the mixture is neutral.
Comparative example 2
The difference from example 1 is that diethyl phosphite is replaced with phosphorous acid.
The adsorption performance of the adsorption resins of example 1 and comparative examples 1 to 2 was tested in different acidic uranium-containing phosphorus-containing wastewater, and the results are shown in table 1.
TABLE 1
As is clear from the above table, the adsorption amount of uranium by the uranium adsorption resin is 40mg/g or more, and the maximum adsorption amount reaches 61.6mg/g. The uranium adsorption resin provided by the invention has a good adsorption effect on uranium in acidic phosphorus-containing uranium-containing wastewater.
When the concentration of phosphate radical is 3.22g/L and the concentration of hydrogen ion is 0.2mol/L, the equilibrium adsorption quantity of uranium is 61.6mg/g, and when the concentration of hydrogen ion is increased to 2.0mol/L, the equilibrium adsorption quantity of uranium can still reach 51.5mg/g, which shows that the uranium adsorption resin has good tolerance to acid.
When the concentration of hydrogen ions is 1.0mol/L and the concentration of phosphate radical is 3.22g/L (converted into the content of phosphorus to be 1.05 g/L), the equilibrium adsorption quantity of uranium is 54.9mg/g, and when the concentration of phosphate radical is increased to 44.4g/L (converted into the content of phosphorus to be 14.5 g/L), the equilibrium adsorption quantity of uranium can still reach more than 40mg/g, which indicates that the uranium adsorption resin has good tolerance to phosphorus.
The present invention is not limited to the above-described embodiments, and any modifications, improvements, substitutions, and the like, which may occur to those skilled in the art, fall within the scope of the present invention without departing from the spirit of the invention.