Preparation method and application of amidoxime-meshed beta-cyclodextrin adsorbent

Abstract

The application relates to a preparation method of a networked amidoxime beta cyclodextrin adsorbent, which comprises the following steps: first, carrying out a first step reaction of beta-cyclodextrin and epichlorohydrin; then, adding acrylonitrile to carry out a second step reaction under a nitrogen atmosphere to obtain a networked beta-cyclodextrin acrylonitrile polymer; and finally, carrying out a third step reaction of the networked beta-cyclodextrin acrylonitrile polymer and hydroxylamine hydrochloride to obtain a networked beta-cyclodextrin amidoxime polymer. The synthesis steps are simple, water is used as a reaction medium (avoiding the use of a large amount of organic solvents), and the environment is good; the prepared adsorbent has excellent selectivity for gallium in Bayer mother liquor; the adsorption capacity of the adsorbent for gallium ions reaches 41.6 mg / g or more, and the saturated adsorption time is extremely short, which is 6 minutes; the adsorbent has excellent adsorption kinetics; in addition, the adsorbent has a stable structure, the adsorbent can be made into a liquid filter paper, has a long service life in the Bayer mother liquor, and the adsorption capacity retention rate is not less than 90% after 5 adsorption-desorption cycles.

Description

Technical Field

[0001] This invention relates to the field of solid adsorbent preparation technology, specifically to a methylamine oxime. Reticulate β Preparation methods and applications of cyclodextrin adsorbents. Background Technology

[0002] Gallium, a crucial rare-dispersed metal, has become an indispensable strategic material in semiconductors, new energy, communications, and defense technologies due to its excellent optical, electrical, and magnetic properties. However, gallium is extremely rare in the Earth's crust and rarely forms independent minerals, primarily occurring as an associated mineral with bauxite and other minerals. Currently, over 90% of the world's metallic gallium is recovered from the Bayer process's circulating mother liquor during alumina production. The efficient, economical, and environmentally friendly enrichment and separation of gallium from complex, high-ionic-strength Bayer solutions or various gallium-containing leachates is a key technological challenge in the field of comprehensive resource utilization.

[0003] Currently, industrial methods for gallium recovery mainly include solvent extraction, electrochemical methods, ion exchange, and adsorption. Among these, adsorption is considered a more promising recovery technology due to its simplicity, environmental friendliness, and wide applicable concentration range. Adsorbent materials containing amylopectin groups (-C(NH2)=N-OH) exhibit good selective adsorption potential because their functional groups can form stable chelates with gallium ions. However, existing amylopectin adsorbent materials still face a series of bottlenecks in practical applications, especially when dealing with the complex composition of Bayer mother liquor. The core shortcomings lie in several major challenges, including environmental issues related to the preparation process, low adsorption performance, and poor structural stability.

[0004] First, the preparation process is complex and environmentally unfriendly. Traditional synthesis methods mostly rely on solution polymerization or stepwise chemical cross-linking, resulting in lengthy synthesis routes and cumbersome steps. The production process requires the use of large amounts of organic solvents and chemical reagents, which not only leads to high production costs but also generates high-concentration organic wastewater that is difficult to treat, resulting in a heavy environmental pollution load, which contradicts the development concept of green chemical industry.

[0005] Secondly, the adsorption capacity is low and the adsorption rate is slow. Limited by the synthesis methods, commercially available or reported amylopectin materials generally face the bottleneck of low functional group grafting rates, resulting in insufficient effective active site density. This severely restricts the diffusion and contact efficiency of gallium ions within the material, manifesting as slow adsorption kinetics. Reaching adsorption equilibrium often takes several hours or more, making it difficult to achieve high-throughput and economical recovery of gallium from low-concentration, large-volume industrial waste within a limited time, thus limiting the overall process efficiency.

[0006] Furthermore, the structural stability and cycle life are insufficient. Existing materials often have poor mechanical strength and chemical stability. In harsh environments such as strong alkalis (e.g., Bayer solutions) or strong acids (e.g., acid leaching solutions), the material matrix is ​​prone to swelling, softening, or even cracking, resulting in increased bed pressure drop or material loss.

[0007] Therefore, developing a novel adsorbent with a simple and green preparation process, high grafting rate of amine oxime groups, large adsorption capacity, stable structure, and high selectivity for gallium ions is of great practical significance and broad application prospects for achieving efficient, economical, and sustainable recovery of gallium resources in complex systems. This would fundamentally solve the core problems of low efficiency, heavy pollution, and short lifespan of existing technologies. Summary of the Invention

[0008] The purpose of this invention is to provide a methylamine oxime. Reticulate β Cyclodextrin adsorbent.

[0009] Another object of the present invention is to provide the above-mentioned amylanoxime. Reticulate β A method for preparing cyclodextrin adsorbents. This method prepares adsorbents without using any organic solvents, effectively improving the adsorption performance and adsorption equilibrium time for gallium ions in strongly alkaline Bayer mother liquor containing other metal ions that may interfere.

[0010] A third objective of this invention is to provide the aforementioned amine oxime. Reticulate β Application of cyclodextrin adsorbents.

[0011] The objective of this invention is achieved through the following technical solution:

[0012] A type of amine oxime Reticulate β Cyclodextrin adsorbent, characterized in that: the structural formula of the adsorbent is: m=5~50, n=10-100.

[0013] Furthermore, the adsorbent is prepared by first reacting β-cyclodextrin with epichlorohydrin in the first step, then adding acrylonitrile in a nitrogen atmosphere to obtain a network β-cyclodextrin acrylonitrile polymer in the second step, and then reacting it with hydroxylamine hydrochloride in the third step to obtain a network β-cyclodextrin acrylonitrile polymer.

[0014] Furthermore, the first step reaction is to convert β Cyclodextrin was dissolved in sodium hydroxide solution, and epichlorohydrin was slowly added dropwise at 40-45°C with stirring, and the reaction was continued for 5-7 hours.

[0015] Furthermore, the β The ratio of cyclodextrin, epichlorohydrin and sodium hydroxide solution is 11~11.5g:10~60mL:80~90mL, and the mass percentage concentration of sodium hydroxide solution is 12~18%.

[0016] Furthermore, the second step involves adding hydrochloric acid solution to neutralize the reaction solution to pH 6.8-7.2 after the first step reaction is completed, then purging with nitrogen gas, adding acrylonitrile and cerium ammonium nitrate at 35-38°C, reacting for 1.5-2.5 hours, filtering to collect the precipitate, washing and drying to obtain the network β-cyclodextrin acrylonitrile polymer.

[0017] Furthermore, the β The ratio of cyclodextrin, cerium ammonium nitrate, and acrylonitrile is 11~11.5g: 0.1~1g: 1~10mL.

[0018] Furthermore, the third step involves dissolving hydroxylamine hydrochloride in deionized water, adjusting the solution to pH 6.8-7.2, then adding the network β-cyclodextrin acrylonitrile polymer, and reacting at 70-80 °C for 2.5-3.5 h.

[0019] Furthermore, the ratio of hydroxylamine hydrochloride, the network β-cyclodextrin acrylonitrile polymer, and deionized water is 1~4g:0.5~2.5g:25~35mL.

[0020] A type of amine oxime Reticulate β The method for preparing cyclodextrin adsorbent is characterized by: firstly, reacting β-cyclodextrin with epichlorohydrin in a first-step reaction, then adding acrylonitrile in a nitrogen atmosphere to carry out a second-step reaction to obtain a network β-cyclodextrin acrylonitrile polymer, and then reacting it with hydroxylamine hydrochloride in a third-step reaction to obtain a network β-cyclodextrin acrylonitrile polymer.

[0021] Furthermore, the first step reaction is to convert β Cyclodextrin was dissolved in sodium hydroxide solution, and epichlorohydrin was slowly added dropwise at 40-45°C with stirring, and the reaction was continued for 5-7 hours.

[0022] Furthermore, the β The ratio of cyclodextrin, epichlorohydrin and sodium hydroxide solution is 11~11.5g:10~60mL:80~90mL, and the mass percentage concentration of sodium hydroxide solution is 12~18%.

[0023] Furthermore, the second step involves adding hydrochloric acid solution to neutralize the reaction solution to pH 6.8-7.2 after the first step reaction is completed, then purging with nitrogen gas, adding acrylonitrile and cerium ammonium nitrate at 35-38°C, reacting for 1.5-2.5 hours, filtering to collect the precipitate, washing and drying to obtain the network β-cyclodextrin acrylonitrile polymer.

[0024] Furthermore, the β The ratio of cyclodextrin, cerium ammonium nitrate, and acrylonitrile is 11~11.5g: 0.1~1g: 1~10mL.

[0025] Furthermore, the third step involves dissolving hydroxylamine hydrochloride in deionized water, adjusting the solution to pH 6.8-7.2, then adding the network β-cyclodextrin acrylonitrile polymer, and reacting at 70-80 °C for 2.5-3.5 h.

[0026] Furthermore, the ratio of hydroxylamine hydrochloride, the network β-cyclodextrin acrylonitrile polymer, and deionized water is 1~4g:0.5~2.5g:25~35mL.

[0027] After crosslinking with epichlorohydrin, β-cyclodextrin forms a continuous, open three-dimensional network of high-molecular-weight β-cyclodextrin. Cyclodextrin (β) CD-RCL provides more grafting sites for grafting polyacrylonitrile side chains, increasing the grafting amount and resulting in a high density of amylopyrime groups (-C(NH2)=NOH) after subsequent ammonium oximeization. The numerous hydroxyl groups on the outer wall of the β-cyclodextrin in the adsorbent can form hydrogen bonds with Ga hydroxyl species, acting as a pre-enrichment and distance-reducing agent, increasing the local gallium ion concentration and assisting in amylopyrime chelation. Secondly, the hydrophilic open network eliminates diffusion resistance within long-range pores, making the active sites highly accessible. Adsorption is controlled by rapid internal diffusion and surface chelation, rather than the traditional slow long-range internal diffusion control, significantly shortening the final adsorption equilibrium time.

[0028] A type of amine oxime Reticulate β A method for preparing a cyclodextrin adsorbent, characterized by comprising the following steps: S1 Synthesis of Network β-Cyclodextrin Acrylonitrile Polymer (β CD-RCL-PAN) β-Cyclodextrin was dissolved in a 12-18% (w / w) sodium hydroxide solution. Epichlorohydrin was slowly added dropwise at 40-45°C with stirring. The reaction was continued for 5-7 hours, after which the reaction was stopped. The reaction solution was neutralized to pH 6.8-7.2 with 5.5-6.5 mol / L hydrochloric acid solution to generate the intermediate product, a network β-cyclodextrin polymer (β...). CD-RCL), then nitrogen gas was introduced to stabilize the reaction system temperature at 35~38℃, acrylonitrile and cerium ammonium nitrate were added, and the reaction was carried out for 1.5~2.5h. After filtration and washing of the precipitate, it was vacuum dried to obtain the target product, a network β-cyclodextrin acrylonitrile polymer. The ratio of cyclodextrin, cerium ammonium nitrate, acrylonitrile, epichlorohydrin, and sodium hydroxide solution is 11~11.5g : 0.1~1g : 1~10mL : 10~60mL : 80~90mL; S2 Synthesis of Network β-Cyclodextrin Amine Oxime Polymer (β-Cyclodextrin Amine Oxime Polymer) CD-RCL-PAO) Hydroxylamine hydrochloride was dissolved in deionized water and the pH was adjusted to 6.8-7.2. Then, a network β-cyclodextrin acrylonitrile polymer was added, and the reaction temperature was raised to 70-80 °C. The reaction was continued for 2.5-3.5 h. After the reaction was completed, the reaction solution was cooled to room temperature, the precipitate was collected by filtration, and washed three times each with deionized water and anhydrous ethanol. The precipitate was then vacuum dried to constant weight, resulting in a pale yellow network β-cyclodextrin acrylonitrile polymer, which is the adsorbent. The ratio of hydroxylamine hydrochloride, network β-cyclodextrin acrylonitrile polymer, and deionized water was 1-4 g: 0.5-2.5 g: 25-35 mL.

[0029] The above method prepares ammonia oxime Reticulate β Application of cyclodextrin adsorbent in the adsorption of gallium ions.

[0030] Furthermore, the said amine oxime Reticulate β Application of cyclodextrin adsorbent in adsorbing gallium ions in Bayer mother liquor that is strongly alkaline and contains interference from other metal ions.

[0031] The present invention has the following technical effects: The synthesis steps in this invention are simple, using water as the reaction medium (avoiding the use of large amounts of organic solvents), which is also environmentally friendly. The prepared adsorbent exhibits excellent selectivity for gallium in strongly alkaline Bayer mother liquor and can significantly resist interference from other metal ions. The adsorption capacity for gallium ions reaches over 41.6 mg / g, and the saturation adsorption time is extremely short, reaching saturation adsorption within 6 minutes, demonstrating excellent adsorption kinetics. In addition, the adsorbent has a stable structure, and the adsorbent of this invention can be made into liquid filter paper. It has a long cycle life in Bayer mother liquor, and after 5 adsorption-desorption cycles, the adsorption capacity retention rate is not less than 90%. Attached Figure Description

[0032] Figure 1 : Flowchart of the preparation reaction of the network β-cyclodextrin-amine oxime polymer adsorbent of the present invention.

[0033] Figure 2 Infrared spectrum of the network β-cyclodextrin polymer of this invention.

[0034] Figure 3 : The 1H NMR spectrum of the network β-cyclodextrin polymer of this invention.

[0035] Figure 4 Infrared spectrum of the network β-cyclodextrin acrylonitrile polymer of this invention.

[0036] Figure 5 Infrared spectrum of the reticulated β-cyclodextrin-amine oxime polymer adsorbent of this invention.

[0037] Figure 6 SEM image of the network β-cyclodextrin-amine oxime polymer adsorbent of this invention.

[0038] Figure 7 BET diagram and BET parameter table of the network β-cyclodextrin amylopectin polymer adsorbent of the present invention.

[0039] Figure 8 Mass loss diagram of the network β-cyclodextrin-amine oxime polymer adsorbent of the present invention.

[0040] Figure 9 The equilibrium adsorption curve of the network β-cyclodextrin-amine oxime polymer adsorbent of the present invention in Bayer solution.

[0041] Figure 10 Selective adsorption experiments of the reticulated β-cyclodextrin-amine oxime polymer adsorbent of this invention.

[0042] Figure 11 The performance of the network β-cyclodextrin-amine oxime polymer adsorbent of this invention in Bayer mother liquor at different pH values.

[0043] Figure 12 The present invention describes the recycling performance of the network β-cyclodextrin-amine oxime polymer adsorbent in Bayer mother liquor.

[0044] Figure 13 This invention compares the adsorption performance of the network β-cyclodextrin-amine oxime polymer adsorbent of this invention with that of other commercial adsorbents under Bayer mother liquor conditions. Detailed Implementation

[0045] The present invention will be specifically described below through embodiments. It should be noted that the following embodiments are only used to further illustrate the present invention and should not be construed as limiting the scope of protection of the present invention. Those skilled in the art can make some non-essential improvements and adjustments to the present invention based on the above description.

[0046] The reagents used in the embodiments of this invention are as follows: β-Cyclodextrin (β-CD), 98%, cerium ammonium nitrate (analytical grade), hydroxylamine hydrochloride (analytical grade), Chengdu Huaxia Reagent Co., Ltd.; acrylonitrile, 99%, Shanghai Aladdin Biochemical Technology Co., Ltd.; anhydrous sodium carbonate, analytical grade, Chengdu Kelong Chemical Co., Ltd.; anhydrous ethanol: ≥99.7%, Chongqing Chuandong Chemical (Group) Co., Ltd.

[0047] Bayer mother liquor: provided by Chongqing Jiulong Wanbo New Material Technology Co., Ltd.

[0048] Example 1 A type of amine oxime Reticulate β The preparation method of cyclodextrin adsorbent includes the following steps: S1 Synthesis of Network β-Cyclodextrin Acrylonitrile Polymer (β CD-RCL-PAN) 11.35 g of β-cyclodextrin was dissolved in 85 mL of 15% sodium hydroxide solution. At 40 °C with stirring, 40 mL of epichlorohydrin was slowly added dropwise to the solution. The reaction was continued for 6 h, then stopped. The reaction solution was neutralized to pH 7 with 6 mol / L hydrochloric acid solution to generate the intermediate product, a network β-cyclodextrin polymer (β... CD-RCL); then nitrogen gas was introduced to stabilize the reaction system temperature at 35 ℃, 6 mL of acrylonitrile and 0.5 g of cerium ammonium nitrate were added, the reaction was carried out for 2 h, the precipitate was filtered and washed 3 times with anhydrous ethanol, and the precipitate was placed at 40 ℃ for vacuum drying to obtain the target product, network β-cyclodextrin acrylonitrile polymer. S2 Synthesis of Network β-Cyclodextrin Amine Oxime Polymer (β-Cyclodextrin Amine Oxime Polymer) CD-RCL-PAO) 2 g of hydroxylamine hydrochloride was dissolved in 30 mL of deionized water, and the pH was adjusted to 7.0 using 0.13 g / mL sodium carbonate solution. Then, 1.5 g of the network β-cyclodextrin acrylonitrile polymer was added to the above solution, and the reaction temperature was raised to 75 °C. The reaction was continued for 3 h. After the reaction was completed, the reaction solution was cooled to room temperature, the precipitate was collected by filtration, and washed three times each with deionized water and anhydrous ethanol. The precipitate was then vacuum dried at 40 °C to constant weight, resulting in a pale yellow network β-cyclodextrin acrylonitrile polymer, which is the adsorbent.

[0049] FT-IR results of network β-cyclodextrin: Infrared results of network β-cyclodextrin are as follows Figure 2 As shown, compared with β-cyclodextrin raw materials, network β-cyclodextrin exhibits higher activity in the 1150–1030 cm⁻¹ range. -The significantly enhanced characteristic absorption peak of the COC ether bond at ¹ indicates that epichlorohydrin successfully underwent a Williamson ether synthesis reaction with the hydroxyl groups of β-CD, forming an ether cross-linked network. Simultaneously, at 3400 cm⁻¹... - The intensity of the hydroxyl characteristic peak near the ¹ decreased, which also confirms that some hydroxyl groups participated in the cross-linking reaction.

[0050] Characterization of the structure of the network β-cyclodextrin crosslinked polymer: The 1H NMR spectrum of the network β-cyclodextrin crosslinked polymer is as follows: Figure 3 As shown, 1 HNMR (400MHz, D2O): δ 5.22-5.11(OH2, OH3, OH4, H1, H8), 4.04 (OH6), 3.91-3.61 (H3, H5, H6), 3.57-3.52 (H2, H4, H7, H9).

[0051] Infrared results of network β-cyclodextrin acrylonitrile: Infrared results of network β-cyclodextrin acrylonitrile are as follows: Figure 4 As shown, compared with the infrared peak of β-cyclodextrin, the network β-cyclodextrin acrylonitrile polymer has a wavelength of 2250 cm⁻¹. -1 The presence of a distinct characteristic peak belonging to the nitrile group indicates that the network β-cyclodextrin acrylonitrile polymer was successfully prepared.

[0052] Infrared results of network β-cyclodextrin amine oxime: Infrared results of network β-cyclodextrin amine oxime are as follows: Figure 5 As shown, the infrared characteristic peaks of the network β-cyclodextrin-amine oxime polymer compared to the network β-cyclodextrin-acrylonitrile polymer are at 2250 cm⁻¹. -1 The characteristic peak belonging to the nitrile group disappears, and C=N (1660cm) -1 ), NO (950 cm -1 These characteristic peaks associated with the ethamidooxime group were significantly enhanced.

[0053] Morphological characterization of the adsorbent: SEM results are as follows Figure 6 As shown, the material exhibits a highly uniform and interconnected three-dimensional porous network structure, with its framework composed of cross-linked cyclodextrin units. The pore size is mainly distributed in the mesoporous-macroporous transition region, forming an open pore system. This continuous network structure has a high specific surface area and good structural stability, which is beneficial for mass transfer processes. By chemically grafting amine oxime groups onto the framework surface as selective coordination sites, efficient and specific capture of gallium ions can be achieved.

[0054] Analysis of the specific surface area and pore size of the adsorbent: Table 1. Specific surface area, empty volume, and average pore size of the network β-cyclodextrin axime polymer.

[0055] An appropriate pore size can significantly reduce the resistance to liquid film diffusion and shallow diffusion, allowing gallium ions in Bayer mother liquor to quickly reach the active sites on the surface and inside, fully contacting the amine oxime groups and achieving rapid adsorption equilibrium. Bayer mother liquor is a high-ionic-strength, high-viscosity system; if the pore size is too large, it means a sparse cross-linked network and thinner pore walls, resulting in poor structural and chemical stability in stirred, highly alkaline, and high-ionic-strength environments. Furthermore, gallium ions diffuse too quickly within the large pores, resulting in a short residence time and insufficient contact with the adsorption sites before flowing out with the mother liquor, leading to a decrease in the dynamic adsorption capacity and removal rate of gallium ions. (See Table 1 and...) Figure 7 As shown, the specific surface area of ​​the adsorbent is approximately 44.029 m² / g, the total pore volume is 0.65 cm³ / g, and the average pore size is 59 nm.

[0056] Thermal stability analysis of the adsorbent: TG-DSC: Results as follows Figure 8 As shown, in stage one (30 °C to 155 °C), the mass loss is approximately 9.81%, due to the removal of water from the adsorbent surface; in stage two (155 °C to 312 °C), the mass loss is as high as 25.16%, due to the decomposition of the amine oxime functional groups; in stage three (312 °C to 659 °C), the mass loss is approximately 26.61%, due to the breakage of the polymer backbone; and in stage three (659 °C to 996 °C), the mass loss is approximately 7.40%, due to the further pyrolysis of the carbonaceous material. In summary, this adsorbent exhibits good thermal stability below 155 °C and is suitable for conventional aqueous phase adsorption and separation processes.

[0057] Performance evaluation of the network β-cyclodextrin-amine oxime polymer adsorbent prepared in this embodiment: The Bayer liquid used in the adsorption experiment was the process mother liquor from the Bayer process for producing Al2O3 at Chongqing Jiulong Wanbo New Material Technology Co., Ltd. The composition of the Bayer liquid used in this paper is shown in Table 2.

[0058] Table 2: Concentrations of various ions in Bayer mother liquor

[0059] Static adsorption test: Take 10 mL aliquots of Bayer solution and add them to 50 mL ground-glass conical flasks. Add a certain amount of geminal oxime adsorbent and shake to adsorb at 40 °C. Take the simulated solutions before and after adsorption, and determine the Ga content using ICP-AES inductively coupled plasma atomic emission spectrometry. 3+The adsorption amount is calculated according to formula (1):

[0060] In the formula, C 0 represents the initial concentration of metal ions in μg / mL. C e The equilibrium concentration of metal ions is expressed in μg / mL. V The volume of the added solution is in mL. m The mass of the added adsorbent is in mg.

[0061] Performance evaluation of adsorbents: (1) Equilibrium adsorption experiment in Bayer solution: A batch experiment was conducted using Bayer solution. Thirty 50 ml conical flasks were filled with 10 mL of Bayer solution, followed by the addition of 10 mg of the network β-cyclodextrin-amine oxime polymer adsorbent of this invention. The ion concentration was measured by ICP-AES every 1 minute to determine the equilibrium adsorption time of the adsorbent in Bayer solution. The results are as follows: Figure 9 As shown, the adsorbent of the present invention exhibits excellent adsorption kinetics, reaching adsorption equilibrium in 6 minutes, and achieving an adsorption capacity as high as 41.6 mg / g.

[0062] (2) Selective Adsorption Experiment: Selectivity is an important aspect of designating adsorbents for the recovery of rare metals from waste. The main purpose of developing such adsorbents is to adsorb and separate gallium from a variety of raw materials. Therefore, simulation experiments were conducted using metal ions that coexist with gallium in most published papers (concentration of each metal ion 50 mg / L, including: gallium, aluminum, vanadium, zinc, copper, zinc, lead; adsorbent dosage 100 mg, adsorption solution volume 10 mL, time 2 h, temperature 40℃, equilibrium pH=3), and the results are as follows. Figure 10 As shown. The adsorbent of this invention exhibits high selectivity for Ga ions. The extremely high adsorption selectivity of the adsorbent for Ga(III) indicates its great application potential in the recovery of Ga(III).

[0063] (3) Experiment on the effect of pH on the adsorption performance of adsorbent: To investigate the adsorption performance of this adsorbent under different pH conditions in the complex environment of real Bayer mother liquor, the pH was adjusted by directly adding nitric acid to the Bayer solution. The changes in gallium ion concentration before and after adsorption were verified to obtain more realistic experimental data. Figure 11 As shown, between pH 12 and 14, the adsorption capacity decreases significantly with increasing pH, and the adsorption capacity is the largest at pH 12, which is 119.4 mg / g. Between pH 2 and 3, the adsorption capacity increases with increasing pH, but not significantly.

[0064] (4) Cycling performance test in Bayer solution: Adsorption-desorption cycle test was conducted under Bayer solution conditions to examine the regeneration practicality of the adsorbent of the present invention in actual use, such as... Figure 12 As shown, under conditions of multiple cycles of use, the adsorption capacity of the adsorbent for gallium is not much different from that of the first use, and the desorption rate does not show significant changes. After five adsorption-desorption cycles, the adsorption capacity retention rate is still above 90%, indicating that the adsorbent has a long service life and can be used multiple times.

[0065] (5) Comparative experiment on adsorption performance with other commercial resins: To highlight the superior performance of the network β-cyclodextrin ammonia oxime polymer adsorbent of the present invention, the same adsorption experiment was conducted using three commercial resins in Bayer mother liquor. The results were compared with the adsorbent prepared in this invention. Figure 13 As shown, the three commercial resins LSC-600, 952, and 200 exhibit extremely low adsorption capacities for gallium in the same Bayer mother liquor, at 2.3 mg / g, 1.6 mg / g, and 1.5 mg / g, respectively. These adsorption capacities for gallium ions are significantly lower than those of the amine oxime prepared in this invention. Reticulate β Cyclodextrin adsorbent.

[0066] Example 2 A type of amine oxime Reticulate β The preparation method of cyclodextrin adsorbent includes the following steps: S1 Synthesis of Network β-Cyclodextrin Acrylonitrile Polymer (β CD-RCL-PAN) 11 g of β-cyclodextrin was dissolved in 80 mL of a 12% sodium hydroxide solution. At 42 °C, with stirring, 10 mL of epichlorohydrin was slowly added dropwise to the solution. The reaction was continued for 5 h, then stopped. The reaction solution was neutralized to pH 6.8 with 5.5 mol / L hydrochloric acid solution, yielding the intermediate product, a network β-cyclodextrin polymer (β...). CD-RCL); then nitrogen gas was introduced to stabilize the reaction system temperature at 36℃, 1 mL acrylonitrile and 0.1 g cerium ammonium nitrate were added, the reaction was carried out for 1.5 h, the precipitate was filtered and washed twice with anhydrous ethanol, and the precipitate was placed at 42 ℃ for vacuum drying to obtain the target product, network β-cyclodextrin acrylonitrile polymer. S2 Synthesis of Network β-Cyclodextrin Amine Oxime Polymer (β-Cyclodextrin Amine Oxime Polymer) CD-RCL-PAO) 1 g of hydroxylamine hydrochloride was dissolved in 25 mL of deionized water, and the pH was adjusted to 6.8 using 0.12 g / mL sodium carbonate solution. Then, 0.5 g of the network β-cyclodextrin acrylonitrile polymer was added to the above solution, and the reaction temperature was raised to 70 °C. The reaction was continued for 2.5 h. After the reaction was completed, the reaction solution was cooled to room temperature, the precipitate was collected by filtration, and washed three times each with deionized water and anhydrous ethanol. The precipitate was then vacuum dried at 42 °C to constant weight, resulting in a pale yellow network β-cyclodextrin acrylonitrile polymer, which is the adsorbent.

[0067] Example 3 A type of amine oxime Reticulate β The preparation method of cyclodextrin adsorbent includes the following steps: S1 Synthesis of Network β-Cyclodextrin Acrylonitrile Polymer (β CD-RCL-PAN) 11.5 g of β-cyclodextrin was dissolved in 90 mL of 18% sodium hydroxide solution. At 45°C, with stirring, 60 mL of epichlorohydrin was slowly added dropwise to the solution. The reaction was continued for 7 hours, after which it was stopped. The reaction solution was neutralized to pH 7.2 with 6.5 mol / L hydrochloric acid solution, yielding the intermediate product, a network β-cyclodextrin polymer (β...). CD-RCL); then nitrogen gas was introduced to stabilize the reaction system temperature at 38℃, 10 mL of acrylonitrile and 1 g of cerium ammonium nitrate were added, the reaction was carried out for 2.5 h, the precipitate was filtered and washed 3 times with anhydrous ethanol, and the precipitate was placed at 45 ℃ for vacuum drying to obtain the target product, the network β-cyclodextrin acrylonitrile polymer. S2 Synthesis of Network β-Cyclodextrin Amine Oxime Polymer (β-Cyclodextrin Amine Oxime Polymer) CD-RCL-PAO) 4 g of hydroxylamine hydrochloride was dissolved in 35 mL of deionized water, and the pH was adjusted to 7.2 using 0.15 g / mL sodium carbonate solution. Then, 2.5 g of the network β-cyclodextrin acrylonitrile polymer was added to the above solution, and the reaction temperature was raised to 80 °C. The reaction was continued for 3.5 h. After the reaction was completed, the reaction solution was cooled to room temperature, the precipitate was collected by filtration, and washed three times each with deionized water and anhydrous ethanol. The precipitate was then vacuum dried at 45 °C to constant weight, resulting in a pale yellow network β-cyclodextrin acrylonitrile polymer, which is the adsorbent.

Claims

1. A type of amine oxime Reticulate β A method for preparing cyclodextrin adsorbents, characterized in that: First, β-cyclodextrin is reacted with epichlorohydrin in the first step reaction. Then, under a nitrogen atmosphere, acrylonitrile is added to carry out the second step reaction to obtain a network β-cyclodextrin acrylonitrile polymer. Finally, it is reacted with hydroxylamine hydrochloride in the third step to obtain a network β-cyclodextrin acrylonitrile polymer.

2. A methylamine oxime as described in claim 1 Reticulate β A method for preparing cyclodextrin adsorbents, characterized in that: The first step reaction is to convert β Cyclodextrin was dissolved in sodium hydroxide solution, and epichlorohydrin was slowly added dropwise at 40-45°C with stirring, and the reaction was continued for 5-7 hours.

3. A methylamine oxime as described in claim 2 Reticulate β A method for preparing cyclodextrin adsorbents, characterized in that: The β The ratio of cyclodextrin, epichlorohydrin and sodium hydroxide solution is 11~11.5g:10~60mL:80~90mL, and the mass percentage concentration of sodium hydroxide solution is 12~18%.

4. A methylamine oxime as described in any one of claims 1-3 Reticulate β A method for preparing cyclodextrin adsorbents, characterized in that: The second step involves adding hydrochloric acid solution to neutralize the reaction solution to pH 6.8-7.2 after the first step reaction is completed. Then, nitrogen gas is introduced, and acrylonitrile and cerium ammonium nitrate are added at 35-38°C. The reaction is carried out for 1.5-2.5 hours. The precipitate is collected by filtration, washed, and dried to obtain a network β-cyclodextrin acrylonitrile polymer.

5. A methylamine oxime as described in claim 4 Reticulate β A method for preparing cyclodextrin adsorbents, characterized in that: The β The ratio of cyclodextrin, cerium ammonium nitrate, and acrylonitrile is 11~11.5g: 0.1~1g: 1~10mL.

6. A methylamine oxime as described in any one of claims 1-5 Reticulate β A method for preparing cyclodextrin adsorbents, characterized in that: The third step involves dissolving hydroxylamine hydrochloride in deionized water, adjusting the solution to pH 6.8-7.2, then adding the network β-cyclodextrin acrylonitrile polymer, and reacting at 70-80 °C for 2.5-3.5 h.

7. A methylamine oxime as described in claim 6 Reticulate β A method for preparing cyclodextrin adsorbents, characterized in that: The ratio of hydroxylamine hydrochloride, the network β-cyclodextrin acrylonitrile polymer, and deionized water is 1~4g:0.5~2.5g:25~35mL.

8. A methylamine oxime Reticulate β A method for preparing cyclodextrin adsorbents, characterized in that, Includes the following steps: S1 Synthesis of Reticulated β-Cyclodextrin Acrylonitrile Polymer β-Cyclodextrin was dissolved in a 12-18% (w / w) sodium hydroxide solution. Epichlorohydrin was slowly added dropwise at 40-45°C with stirring. The reaction was continued for 5-7 hours, then stopped. The reaction solution was neutralized to pH 6.8-7.2 with 5.5-6.5 mol / L hydrochloric acid solution. Nitrogen gas was then introduced to stabilize the reaction system temperature at 35-38°C. Acrylonitrile and cerium ammonium nitrate were added, and the reaction was continued for 1.5-2.5 hours. After filtration and washing of the precipitate, vacuum drying was performed to obtain the target product, a network β-cyclodextrin acrylonitrile polymer. The ratio of cyclodextrin, cerium ammonium nitrate, acrylonitrile, epichlorohydrin, and sodium hydroxide solution is 11~11.5g : 0.1~1g : 1~10mL : 10~60mL : 80~90mL; S2 Synthesis of Network β-Cyclodextrin Amine Oxime Polymer Hydroxylamine hydrochloride was dissolved in deionized water and the pH was adjusted to 6.8-7.

2. Then, a network β-cyclodextrin acrylonitrile polymer was added, and the reaction temperature was raised to 70-80 °C. The reaction was continued for 2.5-3.5 h. After the reaction was completed, the reaction solution was cooled to room temperature, the precipitate was collected by filtration, and washed three times each with deionized water and anhydrous ethanol. The precipitate was then vacuum dried to constant weight, resulting in a pale yellow network β-cyclodextrin acrylonitrile polymer, which is the adsorbent. The ratio of hydroxylamine hydrochloride, network β-cyclodextrin acrylonitrile polymer, and deionized water was 1-4 g: 0.5-2.5 g: 25-35 mL.

9. The amine oxime prepared by the method of claim 8 Reticulate β Application of cyclodextrin adsorbent in the adsorption of gallium ions.

10. The application as described in claim 9, characterized in that, The amine oxime Reticulate β Application of cyclodextrin adsorbent in adsorbing gallium ions in Bayer mother liquor.

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