Fluoride ion adsorbing material based on ionic liquid modification and preparation method thereof

Abstract

The application provides a kind of fluorine ion adsorption material based on ionic liquid modification and a preparation method thereof, and relates to the technical field of adsorption material.The method mixes sodium carbonate and copper sulfate, after electromagnetic stirring, sequentially soaks in concentrated ammonia water and imidazole, and then filters to obtain intermediate product A; intermediate product A and glacial acetic acid are dissolved, then soaked in hydrazine hydrate to obtain intermediate product B; intermediate product B is dissolved in water, and after uniform electromagnetic stirring, sodium hydroxide and imidazole amino salt ionic liquid are alternately added, washed, dried, and calcined to obtain fluorine ion adsorption material based on ionic liquid modification.The application also provides a kind of fluorine ion adsorption material based on ionic liquid modification.The adsorption material has high fluorine ion adsorption capacity at low temperature and room temperature; by utilizing the heat sensitivity of hydrogen bond to the reversible process of HF adsorption, the adsorption material can be recovered by heating and boiling method, and at the same time, the enrichment of HF is realized, without introducing chemical reagents, and it is more environmentally friendly.

Description

Technical Field

[0001] This invention relates to the field of adsorption materials technology, and in particular to a fluoride ion adsorption material based on ionic liquid modification and its preparation method. Background Technology

[0002] In existing technologies, a highly porous structure (BET specific surface area of ​​172.15 m²) is prepared using a multi-element doping strategy. 2 ·g -1 Highly efficient and recyclable F - Adsorbent. This adsorbent uses TiO2 as a matrix and propiolactone pyridine sulfonate as a dopant. This adsorbent exhibits good F... - Adsorption capacity, and F increases with increasing temperature - The adsorption capacity gradually increases (F at 288, 298, 308 and 318 K) - Maximum adsorption capacity q max The values ​​were 152.78, 224.11, 235.10, and 237.18 mg·g, respectively. -1 The adsorbent can be recovered by washing with 63% nitric acid.

[0003] The objective disadvantages of existing technologies are:

[0004] ①F - The adsorption capacity increases with increasing temperature. The adsorbent generally operates at a temperature of 283-293K, during which its adsorption capacity is not good.

[0005] ② The adsorbent recovery requires 63% concentrated nitric acid, and the eluent is strongly acidic, which can easily cause secondary pollution. Summary of the Invention

[0006] The purpose of this invention is to provide a fluoride ion adsorption material based on ionic liquid modification and its preparation method. The fluoride ion adsorption material of this invention has a high fluoride ion adsorption capacity at low and room temperatures.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] A method for preparing a fluoride ion adsorbent based on ionic liquid modification includes:

[0009] Step 1: Mix sodium carbonate and copper sulfate, stir electromagnetically, then soak in concentrated ammonia and imidazole in sequence, and filter to obtain intermediate product A;

[0010] Step 2: Dissolve intermediate product A obtained in Step 1 and glacial acetic acid, then soak in hydrazine hydrate to obtain intermediate product B;

[0011] Step 3: Dissolve intermediate product B obtained in Step 2 in water, stir evenly with electromagnetic stirring, then alternately add sodium hydroxide and imidazole amino ionic liquid, wash, dry, and calcine to obtain fluoride ion adsorption material modified by ionic liquid.

[0012] Preferably, the volume ratio of sodium carbonate to copper sulfate in step one is (1-2):(1-5).

[0013] Preferably, the concentration of sodium carbonate in step one is 0.1-10 mol / L, and the concentration of copper sulfate is 0.1-10 mol / L.

[0014] Preferably, the temperature of the electromagnetic stirring in step one is 20-90℃, and the stirring time is 2-10 hours.

[0015] Preferably, the volume ratio of concentrated ammonia and imidazole in step one is (1-5):(1-5).

[0016] Preferably, the mass ratio of intermediate product A to glacial acetic acid in step two is (10-100):(1-50).

[0017] Preferably, the volume ratio of sodium hydroxide to imidazole amino salt ionic liquid in step three is (1-10):(1-10).

[0018] Preferably, the concentration of sodium hydroxide in step three is 1-10 mol / L, and the concentration of imidazole amino salt ionic liquid is 0.1-2 mol / L.

[0019] Preferably, the roasting temperature in step three is 300-800℃ and the time is 4-8 hours.

[0020] The present invention also provides a fluoride ion adsorbent material based on ionic liquid modification obtained by the above preparation method.

[0021] In the above technical solution, the fluoride ion adsorption material based on ionic liquid modification provided by the present invention has the following beneficial effects:

[0022] This invention provides a fluoride ion adsorbent material modified with ionic liquid and its preparation method. This adsorbent material exhibits high fluoride ion adsorption capacity at both low and room temperatures. Experimental results show that the fluoride ion adsorption capacity of this invention… - The adsorption capacity was further improved at 283, 293, 303, 313 and 323 K. - Maximum adsorption capacity q max The values ​​were 364.8, 337.8, 318.4, 273.9, and 231.9 mg·g, respectively. -1 F near room temperature - Maximum adsorption capacity q maxThe increase can be as high as 50% or more; at the same time, by utilizing the thermal sensitivity of hydrogen bonds to the reversible process of HF adsorption, the HF can be enriched while recovering the adsorbent material through heating and boiling, without the need to introduce chemical reagents, which is more environmentally friendly. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this invention. For those skilled in the art, other drawings can be obtained based on these drawings.

[0024] Figure 1 To illustrate this invention, (a) Langmuir and (b) Freundlich adsorption isotherms were used to fit F at different temperatures. - Adsorption curve on the surface of product C;

[0025] Figure 2 For the product C of this invention to F - Adsorption thermodynamics and kinetic curves;

[0026] Figure 3 The present invention affects the removal of F from product C. - A bar chart of the factors;

[0027] Figure 4 To remove F from product C of this invention - The curve showing the actual application situation. Detailed Implementation

[0028] A method for preparing a fluoride ion adsorbent based on ionic liquid modification includes:

[0029] Step 1: Mix sodium carbonate and copper sulfate, filter by electromagnetic stirring. The preferred temperature of the electromagnetic stirring is 20-90℃, and the preferred stirring time is 2-10 hours. After filtration, wash with anhydrous ethanol 2-5 times, then soak in concentrated ammonia and imidazole in sequence, and filter to obtain intermediate product A. The preferred volume ratio of sodium carbonate to copper sulfate is (1-2):(1-5); the preferred concentration of sodium carbonate is 0.1-10 mol / L, and the preferred concentration of copper sulfate is 0.1-10 mol / L; the preferred volume ratio of concentrated ammonia and imidazole is (1-5):(1-5); the preferred soaking time is 6-24 hours.

[0030] Step 2: Dissolve intermediate product A obtained in Step 1 and glacial acetic acid in water in sequence, then preferably evaporate, concentrate and filter, wash with glacial acetic acid 2-5 times, and soak in hydrazine hydrate for 6-24 hours to obtain intermediate product B; the mass ratio of intermediate product A (g): glacial acetic acid (g): hydrazine hydrate (mL) is (10-100): (1-50): (100-500).

[0031] Step 3: Dissolve intermediate product B obtained in Step 2 in water, stir evenly with electromagnetic stirring, then alternately add sodium hydroxide and imidazole amino salt ionic liquid, wash, dry, and calcine to obtain a fluoride ion adsorbent material modified with ionic liquid. The preferred volume ratio of sodium hydroxide to imidazole amino salt ionic liquid is (1-10):(1-10); the preferred concentration of sodium hydroxide is 1-10 mol / L, and the preferred concentration of imidazole amino salt ionic liquid is 0.1-2 mol / L. The washing is preferably performed sequentially with water, glacial acetic acid, and anhydrous ethanol 2-5 times each; the drying temperature is preferably 40-90℃, and the drying time is preferably 2-8 hours; the calcination temperature is preferably 300-800℃, and the calcination time is preferably 4-8 hours.

[0032] The imidazole amino ionic liquid is commercially available. Preferably, it is an aminoalkyl imidazole nitrate, an aminoalkyl imidazole bis(trifluoromethanesulfonyl)imine salt, an imidazole amino tetrafluoroborate, or an imidazole amino bromide salt. More preferably, it is 1-aminopropyl-3-methylimidazole tetrafluoroborate, 1-aminoethyl-3-methylimidazole bromide, 1-aminoethyl-3-methylimidazole bis(trifluoromethanesulfonyl)imine salt, 1-aminopropyl-3-methylimidazole nitrate, 1-aminopropyl-3-methylimidazole bis(trifluoromethanesulfonyl)imine salt, 1-aminoethyl-3-methylimidazole nitrate, or 1-aminopropyl-3-methylimidazole bromide.

[0033] The present invention also provides a fluoride ion adsorbent material based on ionic liquid modification obtained by the above preparation method.

[0034] To enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings.

[0035] Example 1

[0036] At 20℃, 150 mL of 1 mol / L sodium carbonate and 250 mL of 1 mol / L copper sulfate were mixed and stirred electromagnetically for 6 hours. After filtration, the mixture was washed 2-3 times with anhydrous ethanol, and then soaked in 250 mL of concentrated ammonia and 250 mL of imidazole for 12 hours. After filtration, intermediate product A was obtained. 50 g of intermediate product A and 10 g of glacial acetic acid were dissolved in 100 mL of water, evaporated and concentrated, filtered, washed 2-3 times with glacial acetic acid, and then soaked in 200 mL of hydrazine hydrate for 12 hours to obtain intermediate product B. 20 g of intermediate product B was added to 250 mL of water and stirred electromagnetically until homogeneous. 50 mL of 5 mol / L sodium hydroxide and 50 mL of 1 mol / L 1-aminopropyl-3-methylimidazolium tetrafluoroborate were added alternately. After filtration, the mixture was washed 2-3 times each with water, glacial acetic acid, and anhydrous ethanol. After drying at 60℃ for 6 hours, it was calcined at 500℃ for 6 hours to obtain final product C, which is a fluoride ion adsorbent material based on an ionic liquid modification strategy.

[0037] Example 2

[0038] At 30℃, 150 mL of 1 mol / L sodium carbonate and 500 mL of 1 mol / L copper sulfate were mixed and stirred electromagnetically for 6 hours. After filtration, the mixture was washed 2-3 times with anhydrous ethanol, and then soaked in 250 mL of concentrated ammonia and 250 mL of imidazole for 10 hours. After filtration, intermediate product A was obtained. 50 g of intermediate product A and 10 g of glacial acetic acid were dissolved in 100 mL of water, evaporated and concentrated, filtered, washed 2-3 times with glacial acetic acid, and then soaked in 200 mL of hydrazine hydrate for 12 hours to obtain intermediate product B. 20 g of intermediate product B was added to 250 mL of water and stirred electromagnetically until homogeneous. 50 mL of 5 mol / L sodium hydroxide and 50 mL of 1 mol / L 1-aminopropyl-3-methylimidazolium tetrafluoroborate were added alternately. After filtration, the mixture was washed 2-3 times each with water, glacial acetic acid, and anhydrous ethanol. After drying at 60℃ for 6 hours, it was calcined at 500℃ for 6 hours to obtain final product C, which is a fluoride ion adsorbent material based on an ionic liquid modification strategy.

[0039] Example 3

[0040] At 40℃, 150 mL of 1 mol / L sodium carbonate and 500 mL of 1 mol / L copper sulfate were mixed and electromagnetically stirred for 6 hours. After filtration, the mixture was washed 2-3 times with anhydrous ethanol, and then soaked in 250 mL of concentrated ammonia and 250 mL of imidazole for 12 hours. After filtration, intermediate product A was obtained. 50 g of intermediate product A and 10 g of glacial acetic acid were dissolved in 100 mL of water, evaporated and concentrated, filtered, washed 2-3 times with glacial acetic acid, and then soaked in 200 mL of hydrazine hydrate for 12 hours to obtain intermediate product B. 20 g of intermediate product B was added to 500 mL of water and electromagnetically stirred until homogeneous. 50 mL of 5 mol / L sodium hydroxide and 50 mL of 1 mol / L 1-aminopropyl-3-methylimidazolium tetrafluoroborate were added alternately. After filtration, the mixture was washed 2-3 times each with water, glacial acetic acid, and anhydrous ethanol. After drying at 60℃ for 6 hours, it was calcined at 500℃ for 6 hours to obtain final product C, which is a fluoride ion adsorbent material based on an ionic liquid modification strategy.

[0041] Example 4

[0042] At 50℃, 150 mL of 1 mol / L sodium carbonate and 250 mL of 1 mol / L copper sulfate were mixed and stirred electromagnetically for 6 hours. After filtration, the mixture was washed 2-3 times with anhydrous ethanol, and then soaked in 250 mL of concentrated ammonia and 250 mL of imidazole for 18 hours. After filtration, intermediate product A was obtained. 50 g of intermediate product A and 10 g of glacial acetic acid were dissolved in 100 mL of water, evaporated and concentrated, filtered, washed 2-3 times with glacial acetic acid, and then soaked in 200 mL of hydrazine hydrate for 18 hours to obtain intermediate product B. 20 g of intermediate product B was added to 250 mL of water and stirred electromagnetically until homogeneous. 50 mL of 5 mol / L sodium hydroxide and 50 mL of 1 mol / L 1-aminopropyl-3-methylimidazolium tetrafluoroborate were added alternately. After filtration, the mixture was washed 2-3 times each with water, glacial acetic acid, and anhydrous ethanol. After drying at 70℃ for 6 hours, it was calcined at 500℃ for 6 hours to obtain final product C, which is a fluoride ion adsorbent material based on an ionic liquid modification strategy.

[0043] Example 5

[0044] At 60℃, 150 mL of 1 mol / L sodium carbonate and 250 mL of 1 mol / L copper sulfate were mixed and stirred electromagnetically for 6 hours. After filtration, the mixture was washed 2-3 times with anhydrous ethanol, and then soaked in 250 mL of concentrated ammonia and 250 mL of imidazole for 10 hours. After filtration, intermediate product A was obtained. 50 g of intermediate product A and 10 g of glacial acetic acid were dissolved in 100 mL of water, evaporated and concentrated, filtered, washed 2-3 times with glacial acetic acid, and then soaked in 200 mL of hydrazine hydrate for 10 hours to obtain intermediate product B. 20 g of intermediate product B was added to 250 mL of water and stirred electromagnetically until homogeneous. 50 mL of 5 mol / L sodium hydroxide and 50 mL of 1 mol / L 1-aminoethyl-3-methylimidazolium bromide were added alternately. After filtration, the mixture was washed 2-3 times each with water, glacial acetic acid, and anhydrous ethanol. After drying at 50℃ for 6 hours, it was calcined at 500℃ for 6 hours to obtain final product C, which is a fluoride ion adsorbent material based on an ionic liquid modification strategy.

[0045] Example 6

[0046] At 70℃, 150 mL of 1 mol / L sodium carbonate and 250 mL of 1 mol / L copper sulfate were mixed and stirred electromagnetically for 6 hours. After filtration, the mixture was washed 2-3 times with anhydrous ethanol, and then soaked successively in 250 mL of concentrated ammonia and 250 mL of imidazole for 8 hours. After filtration, intermediate product A was obtained. 50 g of intermediate product A and 10 g of glacial acetic acid were dissolved in 100 mL of water, evaporated and concentrated, filtered, washed 2-3 times with glacial acetic acid, and then soaked in 200 mL of hydrazine hydrate for 8 hours to obtain intermediate product B. 20 g of intermediate product B was added to 250 mL of water and stirred electromagnetically until homogeneous. Then, 50 mL of 5 mol / L sodium hydroxide and 50 mL of... 1 mol / L of 1-aminoethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt was added alternately, filtered, and then washed 2-3 times each with water, glacial acetic acid, and anhydrous ethanol. After drying at 80°C for 6 hours, the product was calcined at 500°C for 6 hours to obtain the final product C, which is a fluoride ion adsorbent material based on an ionic liquid modification strategy.

[0047] Example 7

[0048] At 80℃, 150 mL of 1 mol / L sodium carbonate and 250 mL of 1 mol / L copper sulfate were mixed and stirred electromagnetically for 6 hours. After filtration, the mixture was washed 2-3 times with anhydrous ethanol, and then soaked in 250 mL of concentrated ammonia and 250 mL of imidazole for 6 hours. After filtration, intermediate product A was obtained. 50 g of intermediate product A and 10 g of glacial acetic acid were dissolved in 100 mL of water, evaporated and concentrated, filtered, washed 2-3 times with glacial acetic acid, and then soaked in 200 mL of hydrazine hydrate for 6 hours to obtain intermediate product B. 20 g of intermediate product B was added to 250 mL of water and stirred electromagnetically until homogeneous. 50 mL of 5 mol / L sodium hydroxide and 50 mL of 1 mol / L 1-aminopropyl-3-methylimidazolium nitrate were added alternately. After filtration, the mixture was washed 2-5 times each with water, glacial acetic acid, and anhydrous ethanol. After drying at 90℃ for 6 hours, the mixture was calcined at 500℃ for 6 hours to obtain final product C, which is a fluoride ion adsorbent material based on an ionic liquid modification strategy.

[0049] Example 8

[0050] At 90℃, 150 mL of 1 mol / L sodium carbonate and 250 mL of 1 mol / L copper sulfate were mixed and stirred electromagnetically for 6 hours. After filtration, the mixture was washed 2-3 times with anhydrous ethanol, then soaked successively in 250 mL of concentrated ammonia and 250 mL of imidazole for 14 hours, and filtered to obtain intermediate product A. 50 g of intermediate product A and 10 g of glacial acetic acid were dissolved sequentially in 100 mL of water, evaporated and concentrated, filtered, washed 2-3 times with glacial acetic acid, and then soaked in 200 mL of hydrazine hydrate for 14 hours to obtain intermediate product B. 20 g of intermediate product B was added to 250 mL of water and stirred electromagnetically until homogeneous. Then, 50 mL of 5 mol / L sodium hydroxide and 50 mL of... 1 mol / L of 1-aminopropyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt was added alternately, filtered, and then washed 2-3 times each with water, glacial acetic acid, and anhydrous ethanol. After drying at 90°C for 6 hours, the final product C was obtained by calcining at 500°C for 6 hours, which is a fluoride ion adsorbent material based on an ionic liquid modification strategy.

[0051] Example 9

[0052] At 30℃, 150 mL of 1 mol / L sodium carbonate and 250 mL of 1 mol / L copper sulfate were mixed and stirred electromagnetically for 6 hours. After filtration, the mixture was washed 2-3 times with anhydrous ethanol, and then soaked in 250 mL of concentrated ammonia and 250 mL of imidazole for 15 hours. After filtration, intermediate product A was obtained. 50 g of intermediate product A and 10 g of glacial acetic acid were dissolved in 100 mL of water, evaporated and concentrated, filtered, washed 2-3 times with glacial acetic acid, and then soaked in 200 mL of hydrazine hydrate for 15 hours to obtain intermediate product B. 20 g of intermediate product B was added to 250 mL of water and stirred electromagnetically until homogeneous. 50 mL of 5 mol / L sodium hydroxide and 50 mL of 1 mol / L 1-aminoethyl-3-methylimidazolium nitrate were added alternately. After filtration, the mixture was washed 2-3 times each with water, glacial acetic acid, and anhydrous ethanol. After drying at 40℃ for 6 hours, it was calcined at 500℃ for 6 hours to obtain final product C, which is a fluoride ion adsorbent material based on an ionic liquid modification strategy.

[0053] Example 10

[0054] At 30℃, 150 mL of 1 mol / L sodium carbonate and 250 mL of 1 mol / L copper sulfate were mixed and stirred electromagnetically for 6 hours. After filtration, the mixture was washed 2-3 times with anhydrous ethanol, and then soaked in 250 mL of concentrated ammonia and 250 mL of imidazole for 14 hours. After filtration, intermediate product A was obtained. 50 g of intermediate product A and 10 g of glacial acetic acid were dissolved in 100 mL of water, evaporated and concentrated, filtered, washed 2-3 times with glacial acetic acid, and then soaked in 200 mL of hydrazine hydrate for 14 hours to obtain intermediate product B. 20 g of intermediate product B was added to 250 mL of water and stirred electromagnetically until homogeneous. 50 mL of 5 mol / L sodium hydroxide and 50 mL of 1 mol / L 1-aminopropyl-3-methylimidazolium bromide were added alternately. After filtration, the mixture was washed 2-3 times each with water, glacial acetic acid, and anhydrous ethanol. After drying at 50℃ for 6 hours, it was calcined at 500℃ for 6 hours to obtain final product C, which is a fluoride ion adsorbent material based on an ionic liquid modification strategy.

[0055] Application Example 1

[0056] The 50 mg product C prepared in Example 1 was placed in 400 mL of different concentrations (10, 20, 40, 80, 120, 160 and 200 mg·L⁻¹). -1 ) of F - In the solution, the temperature was sequentially controlled at 283, 293, 303, 313, and 323 K. After thorough mixing and stirring until adsorption equilibrium was reached, 5 mL of the suspension was centrifuged and filtered through a 5 μm filter membrane. The F in the supernatant was determined by ion chromatography. - concentration.

[0057] Figure 1The adsorption isotherms of (a) Langmuir and (b) Freundlich at different temperatures were fitted to F. - The adsorption amount on the surface of product C, and the fitting results are shown in Table 1. Figure 1 As shown in Table 1, the Freundlich fitting parameter (1 / n) at different temperatures is less than 0.6, and increases with increasing temperature, indicating that the adsorption process is easy to occur, and adsorption becomes easier as the temperature decreases. According to the Langmuir isotherm fitting parameters, product C exhibits good adsorption properties for F at 283, 293, 303, 313, and 323 K. - The maximum adsorption capacities were 364.8, 337.8, 318.4, 273.9 and 231.9 mg·L⁻¹, respectively. -1 This also indicates that the adsorption capacity increases with decreasing temperature, demonstrating excellent adsorption performance at room temperature; the regression coefficient of the Langmuir isotherm fitting curve is greater than 0.98 at all temperatures, indicating that F - The adsorption on the surface of product C conforms to the Langmuir adsorption model, i.e., F - The adsorption on the surface of product C is a single-layer uniform adsorption.

[0058] Table 1. Product C adsorption F obtained from Langmuir and Freundlich isotherm fitting. - parameters

[0059]

[0060] Application Example 2

[0061] 50 mg of product C prepared in Example 1 was placed in 400 mL of different concentrations (2, 5, 10 mg·L⁻¹). -1 ) of F - In solution, after centrifuging 5 mL of suspension at 293 K, the solution was filtered through a 5 μm filter membrane, and F was determined sequentially by ion chromatography at different time points (0, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 120, 140, 160, 180, 200 min). - The concentration.

[0062] Figure 2 For product C to F - The adsorption thermodynamics and kinetics curves are shown in Tables 2 and 3, including (a) experimental adsorption thermodynamics curves, (b) linear fitting of the experimental curves for the adsorption thermodynamic equilibrium constant, (c) theoretical linear fitting of the adsorption thermodynamic equilibrium constant, (d) pseudo-first-order, (e) pseudo-second-order, and (f) fitting of the intraparticle diffusion model. Figure 2As shown in Table 2, both experimental measurements and theoretical calculations indicate that within the temperature range of 283K to 323K, ΔH°, ΔS°, and ΔG° are all negative, indicating that product C has a negative effect on F. - Adsorption is a spontaneous process that releases heat and reduces entropy; that is, after adsorption, a stable low-energy adsorbed product is formed, and the initially disordered F in the solution is transformed. - After being adsorbed by product C, the system becomes more ordered, and the disorder of the system decreases accordingly; ΔG° decreases as the temperature decreases, indicating that product C adsorbs F. - The spontaneity of the substance gradually increases as the temperature decreases.

[0063] Depend on Figure 2 As shown in Table 3, at different F - At the given concentration, the adsorption capacity increases rapidly within the first 50 minutes. This is due to the large number of vacant adsorption sites on the surface of product C and the significant concentration gradient between the solution and the surface of product C. During this stage, according to Fick's law, the adsorption rate is controlled by the surface diffusion rate. As time progresses, the adsorption sites on the outer surface of product C are gradually occupied, entering the pore diffusion adsorption stage. After 200 minutes, the adsorption tends to reach equilibrium. Pseudo-first-order, pseudo-second-order, and internal diffusion models were used to fit different concentrations of F. - The kinetic data of adsorption by product C revealed that the regression coefficient R obtained from pseudo-first-order and pseudo-second-order kinetic fitting was... 2 All values ​​were greater than 0.95, and the maximum adsorption amounts in the pseudo-first-order kinetic model were 16.6, 42.2, and 83.0 mg·g⁻¹. -1 ) and experimental data (16.0, 40.0 and 80.0 mg·g) -1 The good match indicates that product C matches product F. - The adsorption is more likely to be physical adsorption than chemical adsorption. An intraparticle diffusion model was used to analyze q at different concentrations. t and t 1 / 2 The curve is divided into two segments, indicating the existence of a multi-step adsorption process: the initial stage is characterized by rapid adsorption with a steep slope and a low intercept, indicating that membrane diffusion plays a controlling role in the adsorption rate at this stage; the second stage has a slower adsorption rate, a lower slope, and a higher intercept, indicating that intraparticle diffusion becomes the rate-controlling step at this stage.

[0064] Table 2 Product C adsorption F - Equilibrium constant fitting parameters

[0065]

[0066] Table 3 shows the C adsorption F obtained from fitting the pseudo-first-order, pseudo-second-order, and intraparticle diffusion models. - parameters

[0067]

[0068] Application Example 3

[0069] 50 mg of product C prepared in Example 1 was placed in a solution containing 5 mg·L⁻¹ -1 Different ions (Cl) - CO3 2- HCO3 - SO4 2- PO4 3- NO3 - K + Ca 2+ Mg 2+ Fe 3+ Al 3+ In a 400 mL solution of [a specific substance], the mixture was thoroughly mixed at 293 K until adsorption equilibrium was reached. 5 mL of the suspension was then centrifuged and passed through a 5 μm filter membrane. The F-value was determined by ion chromatography. - concentration.

[0070] 50 mg of product C prepared in Example 1 was placed in a solution containing 5 mg·L⁻¹ -1 F - Coexisting ions at different concentrations (0, 2, 5, 10 mg·L⁻¹) -1 In a 400 mL mixed solution, the mixture was thoroughly mixed at 293 K until adsorption equilibrium was reached. 5 mL of the suspension was centrifuged, filtered through a 5 μm filter membrane, and F was determined by ion chromatography. - concentration.

[0071] At different temperatures (283, 293, 303, 313, 323, 333, 343, 353, 363, and 373 K), 50 mg of product C prepared in Example 1 was placed in a solution containing 5 mg·L⁻¹ K. -1 F - In a 400 mL mixed solution, after thorough mixing until adsorption equilibrium is reached, 5 mL of the suspension is centrifuged, filtered through a 5 μm filter membrane, and F is determined by ion chromatography. - concentration.

[0072] At different pH values ​​(0-14), 50 mg of product C prepared in Example 1 was placed in a solution containing 5 mg·L⁻¹. -1 F - In a 400 mL mixed solution, after thorough mixing until adsorption equilibrium is reached, 5 mL of the suspension is centrifuged, filtered through a 5 μm filter membrane, and F is determined by ion chromatography. - concentration.

[0073] Figure 3 To investigate the impact of C on F removal in products - Bar chart of factors: (a) adsorption selectivity, (b) anti-interference, (c) F at different temperatures - Removal rate, (d) F at different pH values - Removal rate. (By...) Figure 3 It can be seen that: Product C is related to F - It exhibits excellent selective adsorption performance, with common coexisting ions having minimal impact on it. Furthermore, its adsorption performance decreases with increasing temperature and pH, exhibiting optimal adsorption performance at room temperature.

[0074] Application Example 4

[0075] The product C prepared in Example 1 was subjected to multiple adsorption-desorption cycles using a heating method to evaluate its regeneration potential. 50 mg of product C was added to 400 mL of 5 mg·L⁻¹ [amount missing]. -1 F - In the solution, the filter residue was thoroughly washed, and after adsorption equilibrium was reached, desorption was performed by heating. The solution after desorption equilibrium was centrifuged and passed through a 5 μm filter membrane, and F was determined by ion chromatography. - concentration.

[0076] A chromatographic column with an inner diameter of 11 mm and a length of 20 cm was used to self-assemble a fixed adsorption bed. 10 g of product C was packed to form an adsorption layer with a thickness of 7 cm. Quartz sand with a thickness of 2 cm was packed above and below the adsorption layer. The adsorption layer and quartz sand were separated by 80-mesh polyester fiber.

[0077] 50 mg of product C prepared in Example 1 was added to 400 mL of 5 mg·L⁻¹ solution prepared using actual water bodies such as tap water, lake water, and river water. -1 F - After thorough mixing to adsorption equilibrium in the solution, 5 mL of the suspension was centrifuged and filtered through a 5 μm filter membrane. The F content was then determined by ion chromatography. - concentration.

[0078] Figure 4 Remove F from product C - Actual application curves: (a) Recycled product C versus F - Removal rate, (b)F - The enrichment recovery rate, (c) of product C's F - Breakthrough curve, (d) Product C in actual water bodies at different concentrations of F - The removal rate. (By) Figure 4 It can be seen that after product C undergoes five rounds of heating and recovery, the amount of F in the solution is reduced. - The removal rate can still be as high as 83.7%, and F desorbed from product C into the solution - All were enriched and recovered; with increasing initial concentration, the slope of the adsorption breakthrough curve of the adsorption fixed bed increased significantly, leading to F - The saturation adsorption time was significantly shortened and the adsorption amount was much lower than that of product C. This is because although the F content was higher... - The initial concentration can create a high concentration gradient in the fixed bed, which is conducive to the adsorption of F by the product C.- It provides greater adsorption motive force, but F - It is difficult to achieve a uniform distribution of adsorption sites near the surface of product C, and these sites cannot be fully utilized, resulting in the adsorption fixed bed failing to achieve saturation adsorption of product C in practical applications. Therefore, compared to previous adsorption experiments, the adsorption fixed bed experiment presents a greater challenge to the adsorption performance of product C on fluoride ions. Encouragingly, in the adsorption fixed bed filled with product C, F... - The initial concentrations were 10, 5, and 2 mg·L⁻¹, respectively. -1 Time F - The saturation adsorption times were 20, 25.4, and 38.9 hours, respectively, which are suitable for actual working intensity.

[0079] The foregoing has only described certain exemplary embodiments of the present invention by way of illustration. Undoubtedly, those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the foregoing drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. A method for preparing a fluoride ion adsorbent material modified with an ionic liquid, characterized in that, include: Step 1: Mix sodium carbonate and copper sulfate, stir electromagnetically, then soak in concentrated ammonia and imidazole in sequence, and filter to obtain intermediate product A; Step 2: Dissolve intermediate product A obtained in Step 1 and glacial acetic acid, then soak in hydrazine hydrate to obtain intermediate product B; Step 3: Dissolve intermediate product B obtained in Step 2 in water, stir evenly with electromagnetic stirring, then alternately add sodium hydroxide and imidazole amino salt ionic liquid, wash, dry, and calcine to obtain fluoride ion adsorption material modified by ionic liquid. In step one, the volume ratio of sodium carbonate to copper sulfate is (1-2):(1-5); the concentration of sodium carbonate in step one is 0.1-10 mol / L, and the concentration of copper sulfate is 0.1-10 mol / L; in step three, the volume ratio of sodium hydroxide to imidazole amino salt ionic liquid is (1-10):(1-10); the concentration of sodium hydroxide in step three is 1-10 mol / L, and the concentration of imidazole amino salt ionic liquid is 0.1-2 mol / L.

2. The method for preparing a fluoride ion adsorbent material based on ionic liquid modification according to claim 1, characterized in that, The temperature of the electromagnetic stirring in step one is 20-90℃, and the stirring time is 2-10 hours.

3. The method for preparing a fluoride ion adsorbent material based on ionic liquid modification according to claim 1, characterized in that, The volume ratio of concentrated ammonia and imidazole in step one is (1-5):(1-5).

4. The method for preparing a fluoride ion adsorbent material based on ionic liquid modification according to claim 1, characterized in that, The mass ratio of intermediate product A to glacial acetic acid in step two is (10-100):(1-50).

5. The method for preparing a fluoride ion adsorbent material based on ionic liquid modification according to claim 1, characterized in that, The roasting temperature in step three is 300-800℃, and the time is 4-8 hours.

6. The fluoride ion adsorbent material based on ionic liquid modification obtained by the preparation method of claim 1.

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