Arginine-functionalized copper-aluminum layered double hydroxide, method of preparation and use

Abstract

The application provides arginine functionalized copper-aluminum layered double hydroxide, a preparation method and application. The preparation method comprises the following steps: reacting an alkaline mixed reaction solution containing arginine, a copper salt and an aluminum salt, and aging after the reaction is completed to obtain arginine functionalized copper-aluminum layered double hydroxide. The arginine functionalized copper-aluminum layered double hydroxide provided by the application is suitable for extracting iodine from an iodine-containing material solution or separating bromine and iodine, has excellent adsorption efficiency and adsorption capacity for iodine, and the iodine-bromine separation factor can reach more than 300, so that the separation of bromine and iodine can be realized.

Description

Technical Field

[0001] This invention belongs to the field of iodine adsorption and extraction technology, specifically relating to an arginine-functionalized copper-aluminum layered bimetallic hydroxide, its preparation method, and its application. Background Technology

[0002] Iodine, as a key strategic element, plays an irreplaceable role in many fields, with applications spanning public health, industrial upgrading, and cutting-edge technology, highlighting its increasingly significant strategic value. In nature, iodine is mainly found in sodium nitrate deposits, phosphate rock deposits, salt sedimentary deposits, underground brine, and oilfield well water. In solution, iodine exists primarily as an inorganic salt and anion. Currently, methods for iodine extraction include air blowing, steam distillation, extraction, precipitation, ion exchange adsorption, and membrane separation. Industrially, air blowing and steam distillation are commonly used to prepare bromo-iodine. However, air blowing yields a mixture of elemental bromo-iodine and air, requiring further separation. While air blowing is less demanding in terms of raw iodine concentration and easier to control, it requires large equipment, leading to increased costs, complex processes, and high energy consumption. These drawbacks limit the efficiency and economic benefits of air blowing in practical applications. Membrane separation suffers from high equipment costs, high energy consumption, and the risk of membrane clogging. Precipitation methods are simple to operate and have a fast reaction rate, but they produce a large amount of precipitate and have high processing costs. Adsorption methods, on the other hand, are simple to operate, efficient, and low in cost, and can be used for large-scale production. Therefore, adsorption is a more suitable method for extracting bromine and iodine from salt lake brine, removing excessive bromine and iodine from drinking water, and removing radioactive iodide ions from water.

[0003] Currently, various functional adsorbent materials are used for the adsorption and fixation of iodide ions in water. For example, activated carbon, as a traditional adsorbent, has a certain potential for removing iodide ions from aqueous solutions, but it suffers from limited adsorption capacity, susceptibility to interference from competing ions and solution pH, and usually requires modification to improve its adsorption performance. Natural minerals such as zeolite and clay can be used to treat iodide ions in radioactive wastewater, but they have drawbacks such as high impurity content and difficulty in purification, making direct engineering applications difficult. Metal-based materials, such as silver-based functional materials, can achieve highly efficient and selective removal of iodide ions due to their high reactivity and specific affinity for iodide ions. Silver-based materials have large adsorption capacity, fast kinetic rates, strong resistance to anion interference, and stable structure, exhibiting excellent overall adsorption performance. However, the high price and relatively high biotoxicity of silver raw materials limit their practical application.

[0004] Therefore, providing a low-cost, high-removal-rate iodine adsorbent is one of the urgent problems to be solved in this field. Summary of the Invention

[0005] To solve all or part of the above-mentioned technical problems, the present invention provides the following technical solutions:

[0006] One objective of this invention is to provide a method for preparing arginine-functionalized copper-aluminum layered bimetallic hydroxide, comprising: reacting an alkaline mixed reaction solution containing arginine, copper salt, and aluminum salt, and aging the solution after the reaction to obtain arginine-functionalized copper-aluminum layered bimetallic hydroxide.

[0007] In some embodiments, the preparation method specifically includes:

[0008] Provide arginine solution, as well as metal salt solutions containing copper and aluminum salts;

[0009] The metal salt solution is added to the arginine solution in batches, and then an alkaline solution is added dropwise to adjust the pH of the mixed reaction solution to 9.5-10.5, and the reaction is continued for a preset time.

[0010] In some embodiments, the arginine solution contains 6-10% arginine by mass.

[0011] In some embodiments, the mass percentage concentration of copper salt in the metal salt solution is 4-16%, and the mass percentage concentration of aluminum salt is 5.9-6.6%.

[0012] In some embodiments, the amounts of the arginine solution and the metal salt solution are such that the molar amount of arginine is 30% to 62% of the molar amount of the metal salt.

[0013] In some embodiments, the arginine solution is formed by dissolving arginine in water and has a pH value of 10.5-11.5.

[0014] In some embodiments, the metal salt solution is added dropwise to the arginine solution at a rate of 3 mL / min to 5 mL / min.

[0015] In some embodiments, the alkaline solution contains hydroxides and carbonates. The hydroxides are, for example, sodium hydroxide and / or potassium hydroxide. In some embodiments, the preset time is 20-30 minutes.

[0016] In some embodiments, the aging temperature is 110℃-130℃.

[0017] In some embodiments, the aging time is 12h to 48h.

[0018] A second aspect of the present invention provides an arginine-functionalized copper-aluminum layered bimetallic hydroxide, which is prepared by the preparation method described in any of the technical solutions.

[0019] A third aspect of the present invention provides the application of the arginine-functionalized copper-aluminum layered bimetallic hydroxide in the extraction of iodine from iodine-containing solutions or in the separation of bromine and iodine.

[0020] A fourth aspect of the present invention provides a method for extracting iodine from an iodine-containing liquid, comprising: bringing an adsorbent into full contact with the liquid containing iodide ions, so that the adsorbent adsorbs the iodide ions therein, wherein the adsorbent comprises an arginine-functionalized copper-aluminum layered bimetallic hydroxide.

[0021] This invention utilizes arginine to functionalize copper-aluminum layered bimetallic hydroxides. The carboxyl and amino groups in arginine can react with Cu... 2+ A stable complex is formed, in which the guanidine moiety in the arginine structure is protonated, allowing for the electrostatic adsorption of iodide ions. Furthermore, arginine can adsorb Cu under alkaline conditions. 2+ Reduced Cu + Cu + It has a strong effect on iodide ions, thus significantly improving the material's adsorption performance for iodine.

[0022] In some embodiments, adsorption is carried out at a temperature of 20~50°C.

[0023] In some embodiments, the iodine-containing liquid is iodine-containing wastewater, radioactive iodine-containing water, or brine.

[0024] In some embodiments, the desorption method for arginine-functionalized copper-aluminum layered bimetallic hydroxides adsorbed with iodide ions includes: soaking the arginine-functionalized copper-aluminum layered bimetallic hydroxides adsorbed with iodide ions in an alkaline solution. For example, the material is soaked in a 0.001~0.01 mol / L hydroxide solution (such as NaOH) at a concentration of 10 g / L for 1-2 hours, repeated at least 4 times, then washed with water until neutral and dried.

[0025] The fifth aspect of the present invention provides a method for separating bromine and iodine in a bromine-iodine mixture, comprising: bringing an adsorbent into full contact with a feed solution containing bromine and iodine ions, so that the adsorbent adsorbs the iodine ions therein, separating the adsorbent adsorbed with iodine ions, and retaining the bromine ions in the feed solution, thereby achieving the separation of bromine and iodine; wherein the adsorbent comprises the arginine-functionalized copper-aluminum layered bimetallic hydroxide as described in any of the technical solutions.

[0026] The iodine-functionalized copper-aluminum layered bimetallic hydroxide prepared by this invention can achieve an iodine-bromine separation factor of over 300, thus enabling the separation of bromine and iodine in a bromine-iodine mixture.

[0027] Compared with the prior art, the present invention has at least some or all of the following beneficial effects: the arginine-functionalized copper-aluminum layered bimetallic hydroxide prepared by the present invention has excellent adsorption efficiency and adsorption capacity for iodine; and the material has good bromine and iodine separation performance, with a separation factor of over 300 in some embodiments. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 These are XRD patterns of the arginine-functionalized copper-aluminum layered bimetallic hydroxides prepared in Examples 1-4.

[0030] Figure 2 R is obtained in Example 1 10 XRD comparison of LDH pH10.5 and LDH pH10.5 prepared in Comparative Example 1;

[0031] Figure 3 The samples with different Cu obtained in Examples 1 and 5-7 are 2+ And Al 3+ XRD comparison of arginine-functionalized copper-aluminum layered bimetallic hydroxides at different molar ratios;

[0032] Figure 4 These are XRD comparison images of the materials prepared in Examples 1, 8-9, and Comparative Examples 2-6;

[0033] Figure 5 This is a comparison of XRD patterns of the initial unadsorbed arginine-functionalized copper-aluminum layered bimetallic hydroxide, the adsorbed material, and the desorbed material in Example 10.

[0034] Figure 6 It is the arginine-functionalized copper-aluminum layered bimetallic hydroxide R synthesized in Example 10. 10 -LDH pH9.5 cycling performance graph after five "adsorption-desorption" cycles;

[0035] Figure 7 These are XRD comparison images of the materials obtained in Examples 10-14;

[0036] Figure 8 These are XRD comparison images of the materials synthesized in Example 10 and Comparative Examples 8-10;

[0037] Figure 9 Synthesis of R in Comparative Example 11 x XRD comparison diagram of Cu materials. Detailed Implementation

[0038] The invention will be more fully understood through the following detailed description, which should be read in conjunction with the accompanying drawings. Detailed embodiments of the invention are disclosed herein; however, it should be understood that the disclosed embodiments are merely exemplary of the invention, which may be embodied in various forms. Therefore, the specific functional details disclosed herein should not be construed as limiting, but rather as the basis for the claims and as intended to teach those skilled in the art to employ the representative basis of the invention in different ways in any suitable detailed embodiment.

[0039] In addition, unless otherwise specified, all raw materials used in the following embodiments can be purchased from the market or other sources, and all production and testing equipment used are known in the art, as are the testing methods used.

[0040] The formula for calculating the adsorption amount in the following specific embodiments is as follows:

[0041]

[0042] In the formula, Q e The adsorption capacity of the hybrid material at adsorption equilibrium is expressed in mg / g; CO, C e The numbers represent the initial concentration of iodine in the aqueous phase and the concentration of iodine in the solution at adsorption equilibrium, respectively, in mg / L; V (L) is the volume of the adsorbent; m is the mass of adsorbent added, in g.

[0043] Example 1

[0044] This embodiment provides an arginine-functionalized copper-aluminum layered bimetallic hydroxide and its preparation method, specifically including the following steps:

[0045] (1) Weigh 1.742 g (10 mmol) of arginine Arg(R) and dissolve it in 20 mL of water that has been boiled to remove CO2. Based on its isoelectric point of 10.76, adjust the pH to 11 with 1 mol / L NaOH. Weigh 3.624 g (15 mmol) of Cu(NO3)2·3H2O and 1.8757 g (5 mmol) of Al(NO3)3·9H2O and dissolve them in 25 mL of boiling water to obtain a metal salt solution.

[0046] (2) The metal salt solution was slowly added dropwise to the arginine solution prepared above while stirring. Then, the mixed alkaline solution (containing 0.5 mol / L NaOH and 0.1 mol / L Na2CO3) was slowly added dropwise until the pH of the mixed solution was 10.5. After stirring for 30 min, the solution was transferred to a reaction vessel and aged at 120 °C for 24 h.

[0047] (3) The product obtained from aging was washed with boiling water until neutral and dried at 60 °C to obtain arginine-functionalized copper-aluminum layered bimetallic hydroxide, denoted as R. 10 -LDH pH10.5.

[0048] Examples 2-4

[0049] Examples 2-4 are basically the same as Example 1, except that the aging time is varied according to Table 1 in Examples 2-4. The rest are the same as in Example 1 and will not be described again here.

[0050] Table 1. Aging time of arginine-functionalized copper-aluminum layered bimetallic hydroxides prepared in Examples 1-4

[0051] Figure 1 These are XRD patterns of the arginine-functionalized copper-aluminum layered bimetallic hydroxides prepared in Examples 1-4. Figure 1 It can be seen that, with a reaction time of 12 hours, the diffraction peaks at 2θ = 11.62° and 23.64° are attributed to the (200) and (400) crystal planes of LDH (PDF#00-046-0099), respectively. The presence of less copper oxide indicates that the product prepared by the 12-hour reaction is mainly LDH. However, when the reaction time is extended to 24 hours, the characteristic diffraction peaks corresponding to LDH completely disappear, while the diffraction signals of CuO and Cu2O are significantly enhanced. This indicates that extending the reaction time will destroy the layered crystal structure of LDH, causing it to decompose and gradually transform into copper oxide. Further extending the reaction time to 48 hours, it can be observed that the intensity of the CuO diffraction peak weakens, while the intensity of the Cu2O peak continues to increase. It can be concluded that extending the hydrothermal reaction time will promote the conversion of divalent copper ions to monovalent copper ions in the system, thereby obtaining a product mainly composed of cuprous oxide. Based on the bromine-iodine adsorption capacity in Table 2, the synthesis reaction time is better in the range of 12~24 hours, with 24 hours being the optimal synthesis reaction time.

[0052] Comparative Example 1

[0053] Comparative Example 1 is basically the same as Example 1, except that arginine is not used in the preparation process of Comparative Example 1, and copper-aluminum layered bimetallic hydroxide is obtained, which is denoted as LDH pH10.5.

[0054] Figure 2 R is obtained in Example 1 10 XRD comparison diagram of LDH pH10.5 and LDH pH10.5 prepared in Comparative Example 1.

[0055] The R prepared in Examples 1-4 10 -LDH pH10.5 and LDH pH10.5 prepared in Comparative Example 1 were added at a dosage of 1 g / L to a solution containing 0.1 g / L Br. ‒ and 0.1g / LI ‒ The mixture was placed in a mixed solution (pH 3), shaken in a water bath at 25 ℃ and 200 rpm for 12 h, and then filtered through a 0.45 µm needle filter. The filtrate was collected, and the concentration of bromine and iodine was determined by ion chromatography. The amount of bromine and iodine adsorbed was calculated. The results are shown in Table 2.

[0056] Table 2. Materials from Examples 1-4 and Comparative Example 1 for Br - I - Adsorption capacity

[0057] As can be seen from the results in Table 2, the hybrid materials R obtained at different aging times... 10 The adsorption capacity of bromine and iodine by LDH pH 10.5 did not change significantly. Compared with LDH pH 10.5 in Comparative Example 1, the adsorption capacity of iodine by arginine-functionalized copper-aluminum layered bimetallic hydroxides prepared in Examples 1-4 was significantly enhanced.

[0058] Examples 5-7

[0059] Examples 5-7 are basically the same as Example 1, except that the molar ratio of Cu(NO3)2·3H2O and Al(NO3)3·9H2O is varied according to Table 3 during the preparation process to obtain Cu with different molar ratios. 2+ And Al 3+ Molar ratio of arginine-functionalized copper-aluminum layered bimetallic hydroxides.

[0060] Table 3 Cu content of materials obtained in Examples 1 and 5-7 2+ Al 3+ Moor ratio

[0061] Figure 3 The samples with different Cu obtained in Examples 1 and 5-7 are 2+ And Al 3+ XRD patterns of arginine-functionalized copper-aluminum layered bimetallic hydroxides at different molar ratios. Figure 3 As can be seen, the positions of the main characteristic diffraction peaks of each sample are basically the same, indicating that the change in the copper-aluminum molar ratio did not significantly alter the main crystal structure of the material. With the increase of Cu... 2+ With Al 3+ As the molar ratio increased from 1:1 to 4:1, the intensity of the CuO characteristic peaks at 2θ = 35.61° and 38.70° gradually increased. This phenomenon reveals the regulatory effect of the copper-aluminum molar ratio on the crystal phase composition of the product: when the molar amount of copper is low, the reduction effect of arginine can reduce most of the CuO content. 2+ Converted to Cu + Ultimately, it exists as Cu₂O; as the molar amount of copper increases, the limited reducing power of the system cannot reduce all of the Cu. 2+ Reduction, excess Cu 2+ It exists in the form of CuO.

[0062] The material obtained in the above embodiments was added at a dosage of 1 g / L to a solution containing 0.1 g / L Br. ‒ and 0.1g / LI ‒ The mixture was placed in a mixed solution (pH 3), shaken in a water bath at 25 ℃ and 200 rpm for 12 h, and then filtered through a 0.45 µm needle filter. The filtrate was collected, and the concentration of bromine and iodine was determined by ion chromatography. The amount of bromine and iodine adsorbed was calculated. The results are shown in Table 4.

[0063] Table 4. Effects of R-LDH on 0.1 g / L Br at different Cu and Al molar ratios - I - The amount of each ion adsorbed in the solution

[0064] As can be seen from the results in Table 4, different Cu 2+ And Al 3+ The adsorption capacity of arginine-functionalized hybrid materials synthesized by molar ratio showed little change for bromine and iodine. Taking all factors into consideration, Cu was selected. 2+ With Al 3+ Further experimental studies were conducted using a molar ratio of 3:1.

[0065] Examples 8-9

[0066] Examples 8-9 are basically the same as Example 1, except that the pH value is controlled by a mixed alkali solution in step (2) as shown in Table 5. The rest are the same as in Example 1, and will not be repeated here.

[0067] Comparative Examples 2-6

[0068] Comparative Examples 2-6 are basically the same as Example 1, except that the pH value is controlled by a mixed alkali solution in step (2) as shown in Table 5. The rest are the same as in Example 1, and will not be repeated here.

[0069] Table 5. pH values ​​during the synthesis process of Examples 1, 8-9, and Comparative Examples 2-65

[0070] Figure 4 These are XRD comparison images of the materials obtained in Examples 1, 8-9, and Comparative Examples 2-6. From... Figure 4 It can be seen that under pH 5.5, the sample exhibits characteristic diffraction peaks at 2θ≈10.02° and 20.22°, which are attributed to the (003) and (006) crystal planes of the layered bimetallic hydroxide, respectively, confirming the successful preparation of LDH under these conditions. As the pH increases (6.6~8.5), the characteristic peaks of LDH gradually disappear, while characteristic peaks of basic copper carbonate and copper oxides appear, indicating that high pH destroys the structure of LDH and triggers a phase transformation. Furthermore, as the pH continues to increase, the intensity of the characteristic peaks of CuO and Cu2O gradually increases; when pH ≥ 9.5, the structure tends to stabilize, indicating that the product under these conditions is mainly a mixture of highly crystalline CuO and Cu2O phases. In summary, the pH of the synthesis system has a regulatory effect on the phase composition of the product: weakly acidic conditions (pH=5.5) are a suitable environment for LDH synthesis; as the pH continuously increases, the LDH phase gradually decomposes, eventually transforming into a phase dominated by Cu2O and CuO.

[0071] The materials prepared in the above examples and comparative examples were added at a dosage of 1 g / L to a solution containing 0.1 g / L Br. ‒ and 0.1g / LI ‒ The mixture was placed in a mixed solution (pH 3), shaken in a water bath at 25 ℃ and 200 rpm for 12 h, and then filtered through a 0.45 µm needle filter. The filtrate was collected, and the concentration of bromine and iodine was determined by ion chromatography. The amount of bromine and iodine adsorbed was calculated. The results are shown in Table 6.

[0072] Table 6. Effects of materials prepared under different pH conditions on 0.1 g / L Br - I - The amount of each ion adsorbed in the solution

[0073] As shown in Table 6, the material synthesized at pH 5.5 can achieve co-adsorption of bromine and iodine. With increasing pH, the adsorption capacity of the synthesized material for iodine first decreases and then increases. At pH above 9, the synthesized material has a larger adsorption capacity for iodine, enabling bromine-iodine separation with a separation factor above 197.

[0074] When pH ≥ 9.5, the adsorption capacity of iodine remains essentially constant, reaching a stable and relatively large adsorption capacity, with a bromine-iodine separation factor above 300. Therefore, subsequent studies selected a synthesis condition of pH 9.5.

[0075] Example 10

[0076] (1) Weigh 1.742 g (10 mmol) of arginine Arg(R) and dissolve it in 20 mL of boiling water. Based on its isoelectric point of 10.76, adjust the pH to 11 with 1 mol / L NaOH. Weigh 3.624 g (15 mmol) of Cu(NO3)2·3H2O and 1.8757 g (5 mmol) of Al(NO3)3·9H2O and dissolve them in 25 mL of boiling water to obtain a metal salt solution.

[0077] (2) The metal salt solution was slowly added dropwise to the arginine solution prepared above while stirring. Then the mixed alkali solution (containing 0.5 mol / L NaOH and 0.1 mol / L Na2CO3) was slowly added dropwise until the pH of the mixed solution was 9.5. After stirring for 30 min, the solution was transferred to a reaction vessel and aged at 120 °C for 24 h.

[0078] (3) The product obtained from aging was washed with boiling water until neutral and dried at 60 °C to obtain arginine-functionalized copper-aluminum layered bimetallic hydroxide, namely R. 10 -LDH pH9.5.

[0079] (4) The synthesized arginine-functionalized copper-aluminum layered bimetallic hydroxide was added at a concentration of 1 g / L to a solution with an initial pH of 3 at a concentration of 0.1 g / L. ‒ The solution was placed in a 25 ℃ constant temperature water bath shaker, and the rotation speed was controlled at 200 rpm. After shaking for 5 hours, the solution was removed, filtered with a 0.45 µm needle filter, and the filtrate was collected. The iodine ion content was determined by ion chromatography.

[0080] (5) After washing the solid material with water, soak it in 0.01 mol / L NaOH at a concentration of 10 g / L for 2 h and repeat 4 times to desorb it. Then wash it with water until neutral, dry it and carry out the next adsorption experiment.

[0081] Figure 5 This is a comparison of XRD patterns of the initial unadsorbed arginine-functionalized copper-aluminum layered bimetallic hydroxide, the adsorbed material, and the desorbed material from Example 10. Figure 5 It can be seen that the XRD pattern after the material adsorbs iodide ions shows the characteristic peak of CuI, indicating that iodide ions react with Cu in the material. +In conclusion, the absence of characteristic CuI diffraction peaks in the XRD pattern of the desorbed material indicates that iodine ions can be desorbed from the material.

[0082] Figure 6 This is a graph showing the cyclic performance of the arginine-functionalized copper-aluminum layered bimetallic hydroxide synthesized in Example 10 after five adsorption-desorption cycles. Figure 6 It can be seen that after five cycles of regeneration, the adsorption capacity of iodine decreased to 83% of that in the first cycle, indicating that the material can be reused.

[0083] Examples 11-14

[0084] Examples 11-14 are basically the same as Example 10, except that different amounts of arginine are added in step (1) as shown in Table 7. The rest are the same as in Example 10, and will not be repeated here.

[0085] Table 7. Amount of Arg added during the synthesis process of Examples 10-14

[0086] Figure 7 These are XRD comparison images of the materials obtained in Examples 10-14. Figure 7 As shown, when different amounts of arginine are added, R is synthesized. x At pH 9.5, with increasing arginine dosage, the diffraction peaks corresponding to the Cu₂O(111) crystal plane (2θ = 36.34°) in the XRD pattern gradually increased, while the diffraction peaks at 2θ angles of 35.61°, 38.70°, and 48.50° gradually decreased, corresponding to the diffraction peaks of CuO. This indicates that arginine effectively diffracts Cu₂O under alkaline conditions. 2+ Reduced to Cu + .

[0087] The materials obtained in Examples 10-14 above were added at a dosage of 1 g / L to a solution containing 0.1 g / L Br. - and 0.1g / LI - The mixture was placed in a mixed solution (pH 3), shaken in a water bath at 25 ℃ and 200 rpm for 12 h, and then filtered through a 0.45 µm needle filter. The filtrate was collected, and the concentration of bromine and iodine was determined by ion chromatography. The amount of bromine and iodine adsorbed was calculated. The results are shown in Table 8.

[0088] Table 8. Effects of materials prepared under different pH conditions on 0.1 g / L Br - I - The amount of each ion adsorbed in the solution

[0089] As shown in Table 8, during the synthesis process, the adsorption capacity of the synthesized material for iodine first increased and then decreased with the increase of arginine amount. When the amount of arginine added was 7.5 mmol, the bromine-iodine separation factor of the system could reach over 700, indicating excellent separation effect.

[0090] Comparative Example 7

[0091] The only difference between Comparative Example 7 and Example 1 is that Cu(NO3)2·3H2O is replaced with Mg(NO3)2·6H2O. The rest is the same as Example 1 and will not be repeated here.

[0092] The arginine-functionalized layered bimetallic hydroxides synthesized in Example 1 and Comparative Example 7 were added to 0.1 g / L Br at a dosage of 1 g / L. ‒ and 0.1g / LI ‒ The mixture was placed in a mixed solution (pH 3), shaken in a water bath at 25 ℃ and 200 rpm for 12 h, and then filtered through a 0.45 µm needle filter. The filtrate was collected, and the concentration of bromine and iodine was determined by ion chromatography. The amount of bromine and iodine adsorbed was calculated. The results are shown in Table 7.

[0093] Table 9. Material comparison of 0.1 g / L Br in Example 1 and Comparative Example 7 - I - The amount of each ion adsorbed in the solution

[0094] Experimental results show that replacing copper salts with magnesium salts to synthesize hybrid materials increases the adsorption capacity for bromine while significantly decreasing the adsorption capacity for iodine.

[0095] Comparative Example 8

[0096] The difference between Comparative Example 8 and Example 10 is that Comparative Example 8 does not use Al(NO3)3·9H2O, but only Cu(NO3)2·3H2O; the rest of the procedures are the same as in Example 10. The material synthesized in Comparative Example 8 is denoted as R. 10 -Cu.

[0097] Comparative Example 9

[0098] The difference between Comparative Example 9 and Example 10 is that Comparative Example 9 does not use Cu(NO3)2·3H2O, but only Al(NO3)3·9H2O; the rest of the procedures are the same as in Example 10. The material synthesized in Comparative Example 9 is denoted as R. 10 -Al.

[0099] Comparative Example 10

[0100] The difference between Comparative Example 10 and Example 10 is that arginine was not used in the preparation process of Comparative Example 10, and a copper-aluminum layered bimetallic hydroxide was obtained, denoted as LDH pH9.5.

[0101] Figure 8 It is Example 10 (R) 10 XRD comparison of the materials synthesized with -LDH (pH 9.5) and those synthesized in Comparative Examples 8-10. (See figure) Figure 8 As shown, R 10 -Al exhibits distinct diffraction peaks at 2θ = 35.61°, 38.70°, and 48.50°, corresponding to the (020), (021), and (150) crystal planes of AlO(OH), respectively. 10 The XRD pattern of Cu showed characteristic peaks for both CuO and Cu2O. The high intensity of the CuO diffraction peak indicated that CuO was the dominant phase, while Cu2O existed only in small amounts as a secondary phase. The LDH pH9.5 prepared in Comparative Example 10 exhibited characteristic CuO diffraction peaks at 2θ = 35.61°, 38.70°, and 48.50°, corresponding to the (111), (200), and (202) crystal planes, respectively. This indicates that during the formation of LDH pH9.5, some copper species were converted into oxides. Compared to LDH pH9.5, the R of Example 10... 10 -LDH at pH 9.5 retained the characteristic peaks inherent to LDH, while also showing the characteristic peaks of Cu₂O. This indicates that during the synthesis process, arginine can effectively convert Cu₂O into Cu₂O under alkaline and high temperature (≥393 K) conditions. 2+ Reduced to Cu + .

[0102] The materials from Example 1 and Comparative Examples 8-10 were added to a 0.1 g / L solution at a dosage of 1 g / L. ‒ The solution (pH 3) was shaken in a water bath at 25°C and 200 rpm for 12 h, then removed and filtered through a 0.45 µm needle filter. The filtrate was collected, and the iodine concentration was determined by ion chromatography. The iodine adsorption amount was calculated, and the test results are shown in Table 8.

[0103] Table 10. Effects of the materials from Example 10 and Comparative Examples 8-10 on Br - and I - Ion adsorption capacity

[0104] According to Table 10, Comparative Example 9 (R) 10 The materials in -Al) and Comparative Example 1 showed virtually no adsorption effect on iodine. Comparative Example 8 used R synthesized from arginine and copper. 10- The adsorption capacity of Cu for iodine was only half that of Example 10. This result indicates that Cu2O generated during the synthesis process is the key contributing component for adsorption, while the layered framework provides a good dispersion carrier and stable structure for the active sites. The synergistic effect of the two enhances the adsorption performance of the material.

[0105] Comparative Example 11

[0106] The difference between Comparative Example 11 and Example 10 is that Al(NO3)3·9H2O was not added during the synthesis process, and the amount of arginine added was adjusted. The obtained material was named R. x -Cu. Detailed procedures are as follows: Dissolve 15 mmol of Cu(NO3)2·3H2O in 25 mL of deionized water. Separately, dissolve 10 mmol of arginine (R) in 20 mL of deionized water, and adjust the pH of the arginine solution to 11 by adding 1 mol / L NaOH. While continuously stirring, slowly add the metal salt solution dropwise to the arginine solution, followed by slowly adding a mixed solution of 0.5 mol / L NaOH and 0.1 mol / L Na2CO3 until the pH of the mixture reaches 9.5. After stirring for 30 minutes, transfer the suspension to a 100 mL PTFE-lined autoclave and perform hydrothermal treatment at 120°C for 24 hours. Wash the precipitate repeatedly with deionized water until the supernatant is neutral, and then dry at 60°C. The resulting sample is named R. 2.5 -Cu, R5-Cu, R 10 -Cu、R 15 -Cu、R 20 -Cu、R 25 -Cu and R 30 -Cu. The numerical suffix indicates the amount of arginine (Arg) added to a fixed amount of the precursor mixture (in mmol), as shown in the XRD structure. Figure 9 As shown.

[0107] The synthesized R x -Cu was added to a 0.1 g / L solution at a dosage of 1 g / L. - The solution (pH 3) was shaken in a water bath at 25°C and 200 rpm for 12 h. The solution was then removed, filtered through a 0.45 µm needle filter, and the filtrate was collected. The concentration of bromine and iodine was determined by ion chromatography, and the amount of iodine adsorbed was calculated.

[0108] Table 11. Comparative Example 11 Synthetic Material R x -Cu against I - Ion adsorption capacity

[0109] Depend on Figure 9XRD results show that arginine reacts with copper salt to prepare R x In Cu materials, with increasing arginine content, the characteristic peak at 2θ = 36.34° appears and gradually strengthens, belonging to the Cu₂O (111) crystal plane. When the arginine content reaches 30 mmol, the characteristic peak of CuO is no longer present in the XRD pattern, and Cu… 2+ All of it was converted to Cu₂O. The results indicate that arginine can effectively convert Cu₂O under alkaline and high-temperature (≥393 K) conditions. 2+ Reduced to Cu + Table 11 shows R x The adsorption performance of -Cu showed a significant increasing trend with the increase of arginine dosage during the synthesis process. When the Arg dosage exceeded 20 mmol, the adsorption capacity tended to stabilize and no longer increased.

[0110] In addition, the inventors of this case also conducted experiments with other raw materials, process operations, and process conditions described in this specification, referring to the aforementioned embodiments, and obtained relatively ideal results in all cases.

[0111] All aspects, embodiments, features, and examples of this invention should be considered illustrative and used to explain and illustrate the invention, but not to limit the invention. The scope of the invention is defined only by the claims.

[0112] Although the invention has been described with reference to illustrative embodiments, those skilled in the art will understand that various other changes, omissions, and / or additions can be made without departing from the spirit and scope of the invention, and that elements of the described embodiments can be substituted with substantially equivalents. Furthermore, many modifications can be made without departing from the scope of the invention to adapt particular situations or materials to the teachings of the invention. Therefore, this invention is not intended to be limited to the specific embodiments disclosed for carrying out the invention, but rather is intended to encompass all embodiments falling within the scope of the appended claims.

Claims

1. A method for preparing an arginine-functionalized copper-aluminum layered bimetallic hydroxide, characterized in that, include: An alkaline mixture containing arginine, copper salt, and aluminum salt was reacted, and the mixture was aged after the reaction to obtain arginine-functionalized copper-aluminum layered bimetallic hydroxide.

2. The method for preparing arginine-functionalized copper-aluminum layered bimetallic hydroxide according to claim 1, characterized in that, Specifically, it includes: Provide arginine solution, as well as metal salt solutions containing copper and aluminum salts; The metal salt solution is added to the arginine solution in batches, and then an alkaline solution is added dropwise to adjust the pH of the mixed reaction solution to 9.5-10.5, and the reaction is continued for a preset time.

3. The method for preparing arginine-functionalized copper-aluminum layered bimetallic hydroxide according to claim 2, characterized in that: The arginine solution contains 6-10% arginine by mass percentage. And / or, the mass percentage concentration of copper salt in the metal salt solution is 4-16%, and the mass percentage concentration of aluminum salt is 5.9-6.6%; And / or, the amounts of the arginine solution and the metal salt solution used satisfy the following: the molar amount of arginine is 30% to 62% of the molar amount of the metal salt.

4. The method for preparing arginine-functionalized copper-aluminum layered bimetallic hydroxide according to claim 2, characterized in that: The metal salt solution was added dropwise to the arginine solution at a rate of 3 mL / min to 5 mL / min; And / or, the alkaline solution contains hydroxides and carbonates; And / or, the preset time is 20min-30min.

5. The method for preparing arginine-functionalized copper-aluminum layered bimetallic hydroxide according to any one of claims 1-4, characterized in that: The aging temperature is 110℃-130℃, and / or the aging time is 12h~48h.

6. An arginine-functionalized copper-aluminum layered bimetallic hydroxide, characterized in that, It is prepared by the preparation method according to any one of claims 1-5.

7. The application of the arginine-functionalized copper-aluminum layered bimetallic hydroxide of claim 6 in the extraction of iodine from iodine-containing solutions or in the separation of bromine and iodine.

8. A method for extracting iodine from an iodine-containing liquid, characterized in that, include: The adsorbent is brought into full contact with the liquid containing iodine ions so that the adsorbent adsorbs the iodine ions therein. The adsorbent includes the arginine-functionalized copper-aluminum layered bimetallic hydroxide as described in claim 6.

9. The method for extracting iodine from iodine-containing liquid according to claim 8, characterized in that: Adsorption was carried out at temperatures ranging from 20 to 50°C.

10. A method for separating bromine and iodine in a bromine-iodine mixture, characterized in that, include: The adsorbent is brought into full contact with the feed solution containing bromine and iodine ions, so that the adsorbent adsorbs the iodine ions therein, the adsorbent containing the adsorbed iodine ions is separated, and the bromine ions are retained in the feed solution, thereby achieving the separation of bromine and iodine; the adsorbent includes the arginine-functionalized copper-aluminum layered bimetallic hydroxide as described in claim 6.

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