Preparation method and application of rhenium-imprinted silicon-based composite material

Abstract

The invention discloses a preparation method and application of a rhenium-imprinted silicon-based composite material, and the rhenium-imprinted silicon-based composite material Re (VII)-IIP-DMA is prepared by using a surface ion imprinting technology, taking SiO2 particles as a carrier, taking ReO4 <-> as template ions and taking N, N-dimethylacetamide (DMA) as a functional group through a step-by-step grafting method and the surface ion imprinting technology. Rhenium separation and enrichment are carried out on a single rhenium-containing solution, a binary complex solution and copper smelting waste acid, and the imprinted material has the specific selective recognition capability of rhenium. The prepared silicon-based composite material has the advantages of being wide in application range, high in rhenium selective recognition capacity, good in separation effect, good in material desorption and regeneration performance and the like, and the problem that high-acid and high-anion complex rhenium-containing feed liquid cannot be effectively treated in a traditional rhenium separation method is solved.

Description

Technical Field

[0001] The invention belongs to the technical field of effective extraction of rare metals and preparation of green adsorbents, and in particular relates to a preparation method of a rhenium-imprinted silicon-based composite material and application thereof. Background Art

[0002] Rhenium is the most critical metal for manufacturing single crystal blades of aircraft engines. With the rapid development of aviation industries in various countries, the global demand for rhenium will increase sharply, and the rhenium market will face a supply shortage. Therefore, it is of great significance to improve the utilization rate of rhenium resources. In the past, rhenium in my country was mainly extracted from oxygen pressure leaching solution of molybdenum concentrate, molybdenum / copper roasting smoke and flue gas washing waste acid (smelting waste acid). Among them, copper smelting waste acid is mostly not recycled due to its complex composition, various ion types, extremely low rhenium concentration, and high recycling cost. The volume of copper smelting waste acid is very considerable. According to rough statistics, the rhenium lost from copper smelting waste acid in my country can reach 200-500kg / a, resulting in a large loss of rhenium resources. Therefore, at a time when rhenium resources are becoming increasingly depleted, the efficient recovery and utilization of rhenium resources in copper smelting waste acid is of great strategic significance.

[0003] At present, the methods for separating and recovering rhenium from copper smelting waste acid at home and abroad mainly include chemical precipitation, solvent extraction, ion exchange and adsorption. The chemical precipitation method has the disadvantages of poor selectivity, complex subsequent separation process and poor filterability; the solvent extraction method requires large-phase operation to separate and enrich rhenium from low-rhenium solution, which is easy to cause extraction emulsification or the generation of a third phase, and the residual extractant in the raffinate greatly increases the difficulty of wastewater treatment; the ion exchange method has problems such as low adsorption capacity, limited number of cycles and regeneration, and other impurities such as As that easily cause resin poisoning; the activated carbon, modified biological adsorbent, nitrogen heterocyclic functionalized adsorbent, nano-alumina adsorbent, and superparamagnetic core-shell adsorbent currently used in the adsorption method all have problems such as low rhenium adsorption capacity and easy to be affected by the environment and other ions during the adsorption process.

[0004] Ion imprinting technology, developed based on the principle of ion imprinting, is a new type of highly efficient selective separation technology. It uses specific target ions as templates, combines functional monomers with complementary structures to form chelate compounds, and then elutes the target ions to obtain imprinted materials with multiple action sites on the target ions, which can selectively adsorb target ions and achieve efficient separation and enrichment of target ions. Compared with traditional separation methods, separation technology based on ion imprinting has obvious advantages: it can quickly and efficiently enrich and recover extremely low concentration target ions in large volume solutions under extremely harsh environmental conditions such as high impurity content, high concentration solutes, strong acids and strong bases, and directly obtain high-purity products. The core of ion imprinting technology is to prepare ion imprinted materials (Ionic imprinted polymers, IIPs). A large number of target ion imprinted cavities are distributed inside IIPs. These cavities are highly matched with target ions in terms of spatial structure, size and binding sites, so that IIPs have specific recognition selectivity and excellent binding affinity for target ions. At present, many scholars at home and abroad have conducted research on the preparation of rhenium ion imprinted materials. The carriers are usually selected from silicon materials, biomass materials, functionalized nanomaterials, magnetic Fe3O4, etc. The binding sites are established on the carrier surface by surface modification, improving the mechanical properties of the carrier, etc. The prepared rhenium ion imprinted materials are used to treat rhenium-containing solutions. They have the advantages of high rhenium adsorption efficiency and good selectivity. However, the treatment solutions reported so far are mostly single rhenium-containing solutions or solutions containing cationic impurities. There has been no report on the separation and recovery of rhenium from complex solutions containing anions and cations. Summary of the invention

[0005] In order to overcome the problems in the prior art, the present invention provides a method for preparing a rhenium-imprinted silicon-based composite material and its application, and adopts advanced ion imprinting technology to prepare DMA-based rhenium ion imprinted material, which is used for selectively separating and enriching rhenium from complex anionic and cationic impurity ion solutions such as smelting waste acid.

[0006] In order to solve the above technical problems, the technical solution proposed by the present invention is:

[0007] The present invention provides a method for preparing a rhenium-imprinted silicon-based composite material, comprising the following steps:

[0008] S1, after the silica gel particles are activated, an aminosilane modifier is added in a solvent for surface modification to obtain modified silica gel particles (GXA-SiO2) having primary amine groups;

[0009] S2, under nitrogen protection, the modified silica gel particles and N, N-dimethylacetamide (DMA) were grafted polymerized in a solvent, and then extracted and dried to obtain grafted microparticles (JZMAC-SiO2-DMA);

[0010] S3, under nitrogen protection, epichlorohydrin was added to the grafted particles to quaternize the functional groups, and after the reaction was completed, the functional particles (QJZMAC-SiO2-DMA) were obtained by drying;

[0011] S4. The functional particles are placed in a rhenate solution for adsorption, washed and dried, and then placed in an ammonium rhenate solution for constant temperature reaction. After the reaction, the adsorbed rhenate ions are eluted with an analytical agent to obtain a rhenium-imprinted silicon-based composite material (Re(VII)-IIP-DMA).

[0012] In the present invention, silica gel is used as a carrier, and the hydroxyl groups on the surface of silica gel can be used as functional monomers to enhance the adsorption capacity of silica gel for rhenate. After adding silane for modification, an aminosilane modifier is grafted onto the hydroxyl groups on the surface of silica gel to form a primary amine group, and the primary amine group can form a stable coordination bond with the rhenate, thereby improving the adsorption performance of rhenium. N,N-dimethylacetamide is further used as a functional monomer to be grafted onto the amino group to improve its stability in a solvent. DMA is used as an amine source, and the lone pair of electrons on the nitrogen atom of DMA is used as a nucleophilic reagent to attack the epoxy group of epichlorohydrin, open the epoxy ring, form a nucleophilic substitution intermediate, and realize quaternization transformation. Epichlorohydrin contains a highly reactive epoxy group, which can undergo a nucleophilic substitution reaction with an amine compound to generate a compound with a quaternary ammonium group. Due to its cationic characteristics, the quaternized polymer can effectively adsorb the negatively charged rhenate ion through electrostatic force.

[0013] As an optional embodiment, in the preparation method provided by the present invention, in step S1, the aminosilane modifier is one or more of 3-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, and phenylaminomethyltriethoxysilane, and the ratio of the amount of the silica gel particles, the solvent and the aminosilane modifier used is (5-10) g: (50-100) mL: (5-10) mL.

[0014] In the present invention, the aminosilane modifier is controlled within the above range to obtain the best modification effect. If the amount added is too low, the degree of activation is low, and if the amount added is too high, the cost is increased.

[0015] As an optional embodiment, in the preparation method provided by the present invention, in step S1, the surface modification conditions are to stir the reaction at a constant temperature of 40-60°C for 24 hours. After the reaction is completed, the modified silica gel particles are washed, filtered, and vacuum dried to obtain.

[0016] As an optional embodiment, in the preparation method provided by the present invention, in step S1, the particle size of the silica gel particles is 75-180 μm, the activator is a hydrochloric acid solution with a mass fraction of 6-25%, and the activation conditions are stirring and activating at 80-90°C for 4-8 hours, then washing to neutrality, filtering and vacuum drying for 8-18 hours.

[0017] As an optional embodiment, in the preparation method provided by the present invention, in step S2, the ratio of the amount of modified silica gel particles, solvent and N,N-dimethylacetamide used is (1-2) g: (50-100) mL: (10-20) mL.

[0018] In the present invention, the use of the three is controlled within the above ranges from the perspectives of modification effect, solubility, reactivity, economy, etc., and the best modification effect can be obtained.

[0019] As an optional embodiment, in the preparation method provided by the present invention, in step S2, an initiator is also added to the solvent, the particles are filtered after the grafting reaction for 4-8 hours, extracted with methanol for 12-24 hours, and vacuum dried at 60-90°C for 12-24 hours.

[0020] As an optional embodiment, in the preparation method provided by the present invention, in step S3, the ratio of the amount of grafted microparticles to epichlorohydrin used is = (1-2) g: (50-100) mL.

[0021] Controlling the usage of grafted microparticles and epichlorohydrin within the above range can ensure that epichlorohydrin fully reacts with the surface active points of the grafted microparticles to obtain functional microparticles with the best adsorption effect, avoiding unreacted epoxy groups or waste of raw materials due to excess or insufficient amount.

[0022] As an optional embodiment, in the preparation method provided by the present invention, in step S4, the rhenate solution is a solution containing Re 20-100 mg / L and a pH of 1-9, and the ratio of the amount of the functional particles to the rhenate solution used is (1-2) g: (500-1000) mL.

[0023] As an optional embodiment, in the preparation method provided by the present invention, in step S4, the temperature of the isothermal reaction is 10-30°C, the vacuum drying temperature is 70-100°C, and the analytical agent is 0.5-2.0 mol / L hydrochloric acid, 1.0-3.0 mol / L ammonia water or 0.5-2.0 mol / L sodium hydroxide.

[0024] Based on the same technical concept, the present invention also provides the application of the silicon-based composite material prepared by the above-mentioned preparation method of the rhenium-imprinted silicon-based composite material, wherein the silicon-based composite material is used to separate and enrich rhenium in rhenium-containing smelting waste acid, rhenium-containing material dissolution liquid, and rhenium-containing groundwater.

[0025] As an optional implementation, in the application provided by the present invention, the pH value of the solution of the silicon-based composite material when used is 2-7.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] (1) The N,N-dimethylacetamide perrhenate ion imprinted material prepared by the present invention has high efficiency in separation and enrichment of rhenium, can selectively identify rhenate ions from complex multi-component rhenium-containing solutions, and has strong rhenium selective recognition ability, especially from solutions containing multiple anions of high acid (F - , Cl - 、SO4 2- Selectively separate and enrich rhenium from complex feed solutions (such as argon, sodium bicarbonate, etc.).

[0028] (2) The present invention first grafts the amino group in the aminosilane modifier to the silica gel surface, then grafts and polymerizes N,N-dimethylacetamide, and adopts a step-by-step grafting method to prepare the surface rhenate ion imprinting material, which is beneficial to improving the grafting degree; the use of a silicon-based carrier has low cost, and the hydroxyl group on the silica gel surface can be used as a functional monomer to increase the active site for the rhenate; the use of DMA as a functional monomer can utilize the π bond formed by the amide functional group to enable electrons to delocalize on the N, C, and O atoms in the functional group, greatly increasing the electronegativity of the coordinated atoms, and the N atom can form a complex with the O atom in the rhenate to increase the binding ability; the surface imprinting can significantly improve the efficiency of the rhenate ion imprinting, and is beneficial to the surface adsorbed rhenate ions and OH in the desorbent. - Ion exchange is beneficial to desorption.

[0029] (3) The N,N-dimethylacetamide perrhenate ion imprinted material prepared by the present invention has wide adaptability, simple preparation, good regeneration performance, and good practical promotion.

[0030] (4) The preparation method of the rhenate ion imprinted material prepared by the present invention can also be used to prepare imprinted materials for other ions, because in the preparation process of the anion imprinted material in the present invention, the functional monomer DMA is used to form a stable complex with the target anion through complexation, coordination and other forces, and these forces help to improve the selective adsorption of rhenate ions. In addition, after the rhenate ion anion is removed from the imprinted material after the polymerization reaction, a polymer with specific recognition sites is formed, and these sites match the complex anion in shape, size and chemical properties. The imprinted material that can selectively adsorb the complex anion can also be used for the selective separation of other ions such as chromate, molybdate, technetium, titanate, arsenate, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0032] Figure 1 are infrared spectra of SiO2, GXA-SiO2, JZMAC-SiO2-DMA, QJZMAC-SiO2-DMA and Re(VII)-IIP-DMA;

[0033] Figure 2 Zeta potential diagrams of SiO2, JZMAC-SiO2-DMA and QJZMAC-SiO2-DMA;

[0034] Figure 3 XPS graphs of SiO2, JZMAC-SiO2-DMA and QJZMAC-SiO2-DMA;

[0035] Figure 4 It is the result of the effect of pH value on the adsorption capacity of QJZMAC-SiO2-DMA and Re(VII)-IIP-DMA;

[0036] Figure 5 is the fitted adsorption isotherm of Re(VII)-IIP-DMA adsorbing Re(VII);

[0037] Figure 6 is the adsorption rate of each ion in the binary ion system by Re(VII)-IIP-DMA;

[0038] Figure 7 is the adsorption rate of Re(VII)-IIP-DMA for each ion in industrial waste acid;

[0039] Figure 8 is the ratio of the concentration of impurity ions and rhenate ions in the original solution and the desorbed solution C M / C Re(Ⅶ) (a, b: prepared solution loaded with IIP desorption solution; c, d: industrial waste acid loaded with IIP desorption solution);

[0040] Fig. 9 is the adsorption-desorption cycle performance of Re(VII)-IIP-DMA. DETAILED DESCRIPTION

[0041] In order to facilitate the understanding of the present invention, the present invention will be described more comprehensively and meticulously below in conjunction with the accompanying drawings and preferred embodiments of the present invention, but the protection scope of the present invention is not limited to the following specific embodiments.

[0042] Unless otherwise defined, all professional terms used below have the same meanings as those generally understood by those skilled in the art. The professional terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of the present invention.

[0043] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present invention can be purchased from the market or prepared by existing methods.

[0044] Example 1

[0045] A rhenium imprinted silicon-based composite material (hereinafter referred to as Re(VII)-IIP-DMA imprinted material) is prepared as follows:

[0046] (1) Surface modification of silica gel particles: Weigh 10 g of 150 μm chromatographic silica gel YHH-SiO2 activated with hydrochloric acid and place it in a four-necked flask equipped with a thermometer, a reflux condenser and an electric stirrer. Add 100 mL of solvent (a mixed solution of 1:1 ethanol and water) and 10 mL of a modifier (3-aminopropyltrimethoxysilane). React at 50°C for 24 h with a stirring intensity of 300 r / min. After the reaction is completed, wash repeatedly with ethanol, filter and vacuum dry to obtain modified silica gel particles GXA-SiO2.

[0047] (2) Grafting polymerization functional monomer: Take 1.5g of modified silica gel GXA-SiO2 and place it in a four-necked flask equipped with a thermometer, reflux condenser and electric stirrer, add 80mL of distilled water, 16ml of functional monomer N,N-dimethylacetamide, pass nitrogen for 30min, control the temperature at 35℃, add 0.16g of initiator ammonium persulfate, continue to stir and react at constant temperature for 6h, and collect by vacuum filtration. The collected grafted microparticles are extracted with methanol in a Soxhlet extractor for 24h at a constant temperature of 75℃ to remove the homopolymer adsorbed on the surface of the microparticles. After the extraction, vacuum dry for 24h to obtain grafted microparticles JZMAC-SiO2-DMA.

[0048] (3) Preparation of functional microparticles: 1.0 g of JZMAC-SiO2-DMA was placed in a four-necked flask equipped with a thermometer, a reflux condenser and an electric stirrer, and 50 ml of epichlorohydrin (both as a reaction reagent and a solvent) was added. The mixture was reacted at 60°C for 3 h. After the reaction, the product particles were filtered and collected, washed with acetone for multiple times, and vacuum dried to constant weight to obtain quaternized functional microparticles QJZMAC-SiO2-DMA.

[0049] (4) Preparation of rhenium ion imprinted material: The above QJZMAC-SiO2-DMA was placed in a conical flask, and 500 mL of ammonium rhenate solution (containing Re 100 mg / L, pH = 1) was added. The mixture was shaken at a constant temperature of 25°C for 24 h. The saturated adsorption functional particles after filtration and drying were placed in 100 mL of ammonium rhenate solution. 20 ml of epichlorohydrin (cross-linking agent) was added and stirred at 50°C for 24 h. After the reaction was completed, the mixture was vacuum dried and desorbed with 1 mol / L hydrochloric acid. The mixture was shaken at a constant temperature of 25°C for 4 h, and then washed thoroughly with distilled water until no rhenate ions were detected in the washing liquid. The mixture was further vacuum dried to obtain the rhenium ion imprinted silicon-based composite material Re(VII)-IIP-DMA.

[0050] Each substance in Example 1 was tested. Figure 1 The infrared spectra of SiO2, GXA-SiO2, JZMAC-SiO2-DMA, QJZMAC-SiO2-DMA and Re(VII)-IIP-DMA are shown respectively. Figure 1 In (A), the untreated silica gel particles SiO2 have a peak at 3441 cm -1 The absorption peaks related to silanol and adsorbed water appeared, while the silanol peak of GXB-SiO2 modified with 3-aminopropyltrimethoxysilane (AMPS) was weakened. -1 and 692cm -1 The asymmetric stretching vibration absorption peaks of the CH bond and the bending vibration absorption peaks of the NH bond in the AMPS group appeared at 619 cm -1 A new out-of-plane bending peak of the C=O of the amide group is added at 1630 cm -1 The amide C=O stretching and NH bending peaks at the position are strengthened, indicating that the functional monomer DMA has been successfully grafted and polymerized onto the surface of silica particles; Figure 1 (B) shows that after JZMAC-SiO2-DMA was quaternized with epichlorohydrin (ECH), the -1 and 692cm -1 The C=O and NH characteristic peaks are weakened, and the peak at 720 cm -1 The characteristic peak of C-Cl bond of ECH group appeared, which indicated that the functional monomer DMA reacted with ECH to undergo quaternization reaction, and the quaternized functional microparticles QJZMAC-SiO2-DMA were obtained.

[0051] The Zeta values ​​of the substances in Example 1 are as follows: Figure 2As shown, the Zeta values ​​of SiO2, JZMAC-SiO2-DMA and QJZMAC-SiO2-DMA under different pH conditions are shown. Figure 2 It shows that when pH>4, the Zeta potential of SiO2 particles is negative, indicating that the electronegativity of oxygen atoms on the SiO2 surface is large and the surface carries a negative charge. + The surface is positively charged; when N,N-dimethylacetamide is grafted on the surface of SiO2 particles, the Zeta potential of the grafted particles is positive in a large range of pH < 10.6, which is due to the protonation of the amide N atom in the N,N-dimethylacetamide chain. When pH>4, the Zeta potential of the grafted particles decreases with the increase of pH until it becomes negative when pH>10.6, which is due to the deprotonation of the amide N atom; the Zeta potential change law of the functional particles is basically the same as that of the grafted particles, and their Zeta potential is positive and higher than that of the grafted particles. This is because through quaternization, most of the amide groups are converted into quaternary ammonium cations, making the positive charge density on the surface of the functional particles higher and more stable.

[0052] The XPS spectra of each substance in Example 1 are as follows Figure 3 As shown, the XPS spectra of SiO2, QJZMAC-SiO2-DMA and Re(VII)-IIP-DMA are shown respectively. Figure 3 It can be seen that compared with the initial SiO2 particles, the functional particles and the rhenium ion imprinted silicon-based composite materials both have a new N1s peak at 398.4eV, and the C1s peak at 285.2eV is enhanced, indicating that the functional particles and the rhenium ion imprinted particles have been grafted with the functional monomer DMA containing NC bonds.

[0053] Example 2

[0054] A rhenium imprinted silicon-based composite material (hereinafter referred to as Re(VII)-IIP-DMA imprinted material) is prepared as follows:

[0055] (1) Surface modification of silica gel particles: 30 g of 100 μm untreated chromatography silica gel SiO2 was weighed and placed in a four-necked flask equipped with a thermometer, a reflux condenser and an electric stirrer, and 90 mL of 5% mass concentration hydrochloric acid was added. The mixture was stirred and activated at 100°C for 8 h at a stirring speed of 300 r / min. The mixture was then fully washed with distilled water until neutral, filtered and vacuum dried at 90°C for 24 h to obtain activated silica gel YHH-SiO2; 10 g of activated silica gel YHH-SiO2 was taken, 50 mL of solvent (a mixed solution of ethanol and water in a ratio of 1:1) was added, and 10 mL of a modifier 3-aminopropyltrimethoxysilane (AMPS) was added. The mixture was reacted at a constant temperature of 50°C for 24 h at a stirring intensity of 300 r / min. After the reaction was completed, the mixture was repeatedly washed with ethanol, filtered and vacuum dried to obtain modified silica gel particles GXA-SiO2;

[0056] (2) Graft polymerization of functional monomers: 3.0 g of modified silica gel GXA-SiO2 was placed in a four-necked flask equipped with a thermometer, a reflux condenser and an electric stirrer, and 150 mL of distilled water and 32 mL of functional monomer N,N-dimethylacetamide were added. Nitrogen was introduced for 30 min, and the temperature was controlled at 50°C. 0.32 g of initiator ammonium persulfate was added, and the reaction was continued at a constant temperature and stirred for 6 h. The collected grafted particles were extracted with methanol in a Soxhlet extractor for 24 h at a constant temperature of 75°C to remove the homopolymer adsorbed on the surface of the particles. After the extraction, the particles were dried in a vacuum for 24 h to obtain grafted particles JZMAC-SiO2-DMA;

[0057] (3) Preparation of functional microparticles: 2.0 g of JZMAC-SiO2-DMA was placed in a four-necked flask equipped with a thermometer, a reflux condenser and an electric stirrer, and 100 mL of epichlorohydrin (ECH, which serves as both a reaction reagent and a solvent) was added. The mixture was reacted at 40°C for 4 h. After the reaction was completed, the product particles were filtered and collected, washed with acetone for multiple times, and vacuum dried to constant weight to obtain quaternized functional microparticles QJZMAC-SiO2-DMA.

[0058] (4) Preparation of rhenium ion imprinted material: 1.5 g QJZMAC-SiO2-DMA was placed in a conical flask, and 500 mL ammonium rhenate solution (containing Re 100 mg / L, pH = 3) was added. The mixture was shaken at a constant temperature at 30°C for 18 h. After filtration and drying, 1.0 g of saturated adsorbed functional particles was placed in 100 mL ammonium rhenate solution. 20 mL epichlorohydrin (cross-linking agent) was added and stirred at 50°C for 24 h. After the reaction was completed, the mixture was vacuum dried and desorbed with 1 mol / L hydrochloric acid. The mixture was shaken at a constant temperature at 25°C for 4 h, and then washed thoroughly with distilled water until no rhenate ions were detected in the washing solution. The mixture was further vacuum dried to obtain Re(VII)-IIP-DMA imprinted material.

[0059] Example 3

[0060] A rhenium imprinted silicon-based composite material (hereinafter referred to as Re(VII)-IIP-DMA imprinted material) is prepared as follows:

[0061] (1) Surface modification of silica gel particles: 30 g of 80 μm untreated chromatography silica gel SiO2 was weighed and placed in a four-necked flask equipped with a thermometer, a reflux condenser and an electric stirrer, and 150 mL of 8% hydrochloric acid was added. The mixture was stirred and activated at 90°C for 6 h at a stirring speed of 300 r / min. The mixture was then fully washed with distilled water until neutral, filtered and vacuum dried at 85°C for 24 h to obtain activated silica gel YHH-SiO2; 10 g of YHH-SiO2 was taken, 100 mL of solvent (a mixed solution of ethanol and water in a ratio of 1:1) was added, and 10 mL of the modifier 3-aminopropyltrimethoxysilane (AMPS) was added. The mixture was reacted at a constant temperature of 50°C for 24 h at a stirring intensity of 300 r / min. After the reaction was completed, the mixture was repeatedly washed with ethanol, filtered and vacuum dried to obtain modified silica gel particles GXA-SiO2;

[0062] (2) Graft polymerization of functional monomers: 3.0 g of GXA-SiO2 was placed in a four-necked flask equipped with a thermometer, a reflux condenser and an electric stirrer, and 160 mL of distilled water and 32 mL of functional monomer N,N-dimethylacetamide were added. Nitrogen was introduced for 30 min, and the temperature was controlled at 20°C. 0.32 g of initiator ammonium persulfate was added, and the reaction was continued at a constant temperature and stirred for 6 h. The collected grafted particles were extracted with methanol in a Soxhlet extractor for 24 h at a constant temperature of 75°C to remove the homopolymer adsorbed on the surface of the particles. After the extraction, the particles were dried in a vacuum for 24 h to obtain grafted particles JZMAC-SiO2-DMA;

[0063] (3) Preparation of functional microparticles: 2.0 g of JZMAC-SiO2-DMA was placed in a four-necked flask equipped with a thermometer, a reflux condenser and an electric stirrer, and 100 mL of epichlorohydrin (ECH, which serves as both a reaction reagent and a solvent) was added. The mixture was reacted at 70°C for 2 h. After the reaction was completed, the product particles were filtered and collected, washed with acetone for multiple times, and vacuum dried to constant weight to obtain quaternized functional microparticles QJZMAC-SiO2-DMA.

[0064] (4) Preparation of rhenium ion imprinted material: 1.5 g QJZMAC-SiO2-DMA was placed in a conical flask, and 500 mL ammonium rhenate solution (containing Re 100 mg / L, pH = 5) was added. The mixture was shaken at a constant temperature of 10°C for 30 h. After filtration and drying, 1.0 g of saturated adsorbed functional particles was placed in 100 mL ammonium rhenate solution. 20 mL of epichlorohydrin (cross-linking agent) was added and stirred at 50°C for 24 h. After the reaction was completed, the mixture was vacuum dried and desorbed with 1 mol / L hydrochloric acid. The mixture was shaken at a constant temperature of 10°C for 4 h and then washed thoroughly with distilled water until no rhenate ions were detected in the washing solution. The mixture was further vacuum dried to obtain Re(VII)-IIP-DMA imprinted material.

[0065] Example 4

[0066] The application of Re(VII)-IIP-DMA imprinted material in separation and enrichment of rhenate ions, i.e., the method for selective separation and enrichment of rhenium, comprises the following steps:

[0067] The initial rhenium concentration of the sample solution to be tested was adjusted to 80 mg / L, the solution was adjusted to different acidities, Re(VII)-IIP-DMA imprinting material was added at a dosage of 0.4 g / L, and adsorbed at 25°C for 12 h at an oscillation rate of 50 r / min, and eluted with an eluent.

[0068] (1) Adsorption effect of rhenium at different acidities

[0069] Method: 0.01 g of the rhenium ion imprinted material Re(VII)-IIP-DMA prepared in Example 1 was added to 25 mL of 1, 3, 5, 7, 9 and H + The rhenium solution with a concentration of 2 mol / L (initial rhenium concentration of 80 mg / L) was adsorbed at 25°C for 12 hours under shaking, filtered, and the rhenium concentrations in the filtrate and the original solution were analyzed to calculate the rhenium adsorption capacity. At the same time, a comparative test was conducted, and the adsorbent used the non-imprinted functional particles QJZMAC-SiO2-DMA prepared in Example 1.

[0070] The result is shown in Figure 4. Figure 4 It can be seen that when the pH value of the solution changes from -0.02 (H + 2mol / L) to 3, the adsorption capacity of functional microparticles and imprinted microparticles for Re(VII) increased significantly. When the solution pH = 3, the maximum adsorption capacity of functional microparticles and imprinted microparticles for Re(VII) was 47.1mg / g and 59.6mg / g, respectively. After that, the adsorption capacity of Re(VII) decreased significantly as the solution pH continued to increase. This is because the amino group on the functional monomer DMA is easily protonated under acidic conditions. When the pH is less than 3, the lower the pH value, the higher the degree of protonation. When acidified, SO4 2-It will compete with Re(VII) for adsorption, so the adsorption capacity of rhenium decreases with decreasing pH value; when the solution pH is greater than 3, the degree of protonation of DMA amines gradually weakens, especially when pH is greater than 7, the surface adsorption sites are negatively charged, and the OH in the solution - Competitive adsorption with Re(VII), therefore, the adsorption capacity of rhenium decreases with increasing pH. At the same pH value, the adsorption capacity of imprinted microparticles for rhenium is greater than that of functional microparticles.

[0071] (2) Isotherm adsorption curve

[0072] 25 mL of Re(VII) solution of different concentrations was transferred respectively into several 50 mL polyethylene centrifuge tubes, 0.01 g of imprinted microparticles were accurately weighed and added into the centrifuge tubes, and the mixture was oscillated in a water bath at 25°C for 24 h to reach adsorption equilibrium. The mixture was centrifuged and stratified in a centrifuge, and the supernatant was sampled for analysis of Re(VII) content. The adsorption capacity of rhenium was calculated, and the experimental data obtained were correlated with the Langmuir and Freundlich isotherm models, and the isotherm adsorption curve of the imprinted material was drawn.

[0073] Results from Figure 5 As shown by Figure 5 It can be seen that at pH = 3, the maximum adsorption capacity of the imprinted microparticles for Re(VII) is 77.8 mg g -1 The adsorption capacity of rhenium obtained from the imprinted microparticle experiment was 77.8 mg g -1 The Langmuir model calculated value is 78.6 mg·g -1 The results are basically consistent, indicating that the adsorption of rhenium by imprinted particles belongs to monolayer adsorption, which is consistent with the Langmuir adsorption isotherm model.

[0074] (3) Complex binary system solution adsorption experiment

[0075] 0.01 g of the imprinted microparticles prepared in Example 1 were weighed into polyethylene centrifuge tubes, and 25 mL of the prepared binary ion solution (the components are shown in Table 1) was added. The mixture was oscillated in a water bath at 25° C. for 12 h, and centrifuged in a centrifuge to separate the particles. The equilibrium concentrations of Re(VII) and impurity ions in the supernatant of the centrifuge tube were determined, and the adsorption rate was calculated.

[0076] Table 1 Preparation of binary ion mixed solution composition / mg / L

[0077]

[0078] The adsorption results are as follows Figure 6 As shown in the figure, after the binary ion mixture was adsorbed by Re(VII)-IIP-DMA, Re(VII), Cu 2+ 、Zn 2+ , Mn 2+ 、F- , Cl - 、SO4 2- The adsorption rates (%) are 96.30%, 2.50%, 0.50%, 0.50%, 9.1%, 8.5% and 13.4% respectively. The rhenium adsorption rate is much higher than that of other impurity ions, indicating that Re(VII)-IIP-DMA has the ability to selectively adsorb rhenium.

[0079] (4) Experiment on adsorption of waste acid from industrial copper smelting

[0080] The method is the same as above. The composition of industrial copper smelting waste acid is shown in Table 2.

[0081] Table 2 Main components of waste acid from a copper smelting plant in Guangxi

[0082] element Re(VII) <![CDATA[Cu 2+ ]]> <![CDATA[Zn 2+ ]]> <![CDATA[Mn 2+ ]]> <![CDATA[F - ]]> <![CDATA[Cl - ]]> <![CDATA[SO4 2- ]]> As(V) content 18.6mg / L 5.90mg / L 1.38mg / L 1.29mg / L 1.09g / L 5.15g / L 55.3g / L 2.99g / L

[0083] Note: Acidity is 2mol / LH +

[0084] Figure 7 is the adsorption rate of Re(VII)-IIP-DMA to each ion in the solution, Figure 7 The results show that the adsorption rate of Re(VII)-IIP-DMA for Re(VII) is much higher than that for other impurity ions, and the adsorption rate of rhenium is as high as 90.6%, while that of other ions Cu 2+ 、Zn 2+ , Mn 2 + 、F - , Cl - 、SO4 2- The adsorption rates of Re(VII)-IIP-DMA and As(V) were only 3%, 0.02%, 0.01%, 9.1%, 10.4%, 14.7% and 8.9%, respectively, indicating that Re(VII)-IIP-DMA still has good specific recognition for Re(VII) in industrial waste acid.

[0085] (5) Elution effect of different desorbents on rhenium-loaded imprinted materials

[0086] Take 0.01g of rhenium-loaded imprinted particles, place them in a 100ml beaker, add 50mL of desorbent, stir at a constant temperature of 25℃ for 3h, and stir at a speed of 400r / min. After standing and separating, vacuum filter with a 0.45μm filter membrane, measure the concentrations of Re(VII) ions and impurity ions in the filtrate, and calculate the Re(VII) ion desorption rate and the Re(VII) / impurity ion molar ratio in the desorption solution.

[0087] Table 3 shows the effect of different desorbents on the elution of Re(VII) from Re(VII)-IIP-4VP. The results show that the desorption of rhenium from Re(VII)-IIP-DMA using hydrochloric acid is more effective, with a rhenium desorption rate greater than 95%. The rhenium desorption rate from industrial waste acid loaded Re(VII)-IIP-DMA is slightly lower than that from the prepared solution.

[0088] Table 3 Effect of different desorbents on the elution of Re(VII) from Re(VII)-IIP-DMA

[0089]

[0090] The results are as follows Figure 8 It shows that the ratio of impure rhenium in the prepared solution and the ammonia desorption solution of Re(VII)-IIP-DMA loaded with industrial waste acid is significantly lower than that in the original solution, which indicates that the purity of Re(VII) ions in the ammonia eluate is significantly improved, indicating that the selective adsorption and efficient purification of Re(VII) in complex acidic solutions can be achieved through the rhenium ion imprinting material Re(VII)-IIP-DMA.

[0091] (6) Cyclic performance of the rhenium ion imprinted material Re(VII)-IIP-DMA

[0092] In order to investigate the cyclic regeneration and stability of the imprinted material Re(VII)-IIP-DMA, an adsorption-elution cycle experiment was conducted on Re(VII)-IIP-DMA. Adsorption conditions: 0.01 g of imprinted microparticles were dispersed in 25 mL of 30 mg / L Re(VII) solution (pH = 3), and oscillated at 25 ° C for 3 h; desorption conditions: the adsorbed loaded imprinted microparticles were dispersed in 3 mol / L ammonia water for elution, and stirred at 25 ° C for 3 h. The experimental results are shown in Fig. 9 . Fig. 9 It shows that after 5 cycles of adsorption-desorption experiments, the adsorption amount of Re(VII) by the imprinted material Re(VII)-IIP-DMA did not decrease significantly and still maintained an adsorption capacity of 55.9 mg·g-1, indicating that the imprinted material Re(VII)-IIP-DMA can be efficiently regenerated and has good reuse performance.

[0093] Compared with other amide compounds, N,N-dimethylacetamide is used in the present invention for molecular dynamics theoretical calculations, and the conclusion also proves that DMA has the best selectivity.

[0094] The above contents are further detailed descriptions of the present invention in combination with specific preferred embodiments, and it cannot be determined that the specific implementation of the present invention is limited to these descriptions. For ordinary technicians in the field to which the present invention belongs, several simple deductions or substitutions can be made without departing from the concept of the present invention, which should be regarded as falling within the scope of protection of the present invention.

Claims

1. A method for preparing a rhenium-imprinted silicon-based composite material, characterized in that: The following steps are involved: S1, after the silica particles are activated, an aminosilane modifier is added in a solvent for surface modification to obtain modified silica particles having primary amine groups; S2. Under nitrogen protection, grafting the modified silica gel particles and N,N-dimethylacetamide in a solvent, and then extracting and drying to obtain grafted microparticles; S3, under nitrogen protection, adding epichlorohydrin to the grafted microparticles to quaternize the functional groups, and drying after the reaction to obtain functional microparticles; S4. The functional microparticles are placed in a rhenate solution for adsorption, washed and dried, and then placed in an ammonium rhenate solution for constant temperature reaction. After the reaction, the adsorbed rhenate ions are eluted with an analytical agent to obtain a rhenium-imprinted silicon-based composite material.

2. The method for preparing the rhenium imprinted silicon-based composite material according to claim 1, characterized in that: In step S1, the silane modifier is 3-aminopropyltrimethoxysilane, and the ratio of the amount of the silica gel particles, the solvent and the aminosilane modifier is (5-10) g: (50-100) mL: (5-10) mL.

3. The method for preparing the rhenium-imprinted silicon-based composite material according to claim 1 or 2, characterized in that: In step S1, the surface modification conditions are to stir and react at a constant temperature of 40-60° C. for 24 hours. After the reaction is completed, the modified silica gel particles are washed, filtered, and vacuum dried to obtain the modified silica gel particles.

4. The method for preparing the rhenium-imprinted silicon-based composite material according to claim 1 or 2, characterized in that: In step S1, the particle size of the silica gel particles is 75-180 μm, the activator is a hydrochloric acid solution with a mass fraction of 6-25%, the activation conditions are stirring and activating at 80-90° C. for 4-8 hours, then washing to neutrality, filtering and vacuum drying for 8-18 hours.

5. The method for preparing the rhenium imprinted silicon-based composite material according to claim 1, characterized in that: In step S2, the ratio of the amount of modified silica gel particles, solvent and N,N-dimethylacetamide used is (1-2) g: (50-100) mL: (10-20) mL.

6. The method for preparing the rhenium imprinted silicon-based composite material according to claim 1 or 5, characterized in that: In step S2, an initiator is also added to the solvent, and after the grafting reaction for 4-8 hours, the particles are filtered, extracted with methanol for 12-24 hours, and vacuum dried at 60-90° C. for 12-24 hours.

7. The method for preparing the rhenium imprinted silicon-based composite material according to claim 1, characterized in that: In step S3, the ratio of the amount of grafted microparticles to the amount of epichlorohydrin used is = (1-2) g: (50-100) mL.

8. The method for preparing the rhenium imprinted silicon-based composite material according to claim 1 or 7, characterized in that: In step S4, the rhenate solution is a solution containing Re 20-100 mg / L and a pH of 1-9, and the ratio of the functional particles to the rhenate solution is (1-2) g: (500-1000) mL; the isothermal reaction temperature is 10-30°C, the vacuum drying temperature is 70-100°C, and the analytical agent is 0.5-2.0 mol / L hydrochloric acid, 1.0-3.0 mol / L ammonia water or 0.5-2.0 mol / L sodium hydroxide.

9. Use of the silicon-based composite material prepared by the method for preparing the rhenium-imprinted silicon-based composite material according to any one of claims 1 to 8, characterized in that: The silicon-based composite material is used for separating and enriching rhenium in rhenium-containing smelting waste acid, rhenium-containing material dissolution liquid, and rhenium-containing groundwater.

10. The use according to claim 9, characterized in that: When the silicon-based composite material is used, the pH value of the solution is 2-7.

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