A kind of amidoxime-based polymer adsorbent material and its preparation method and application

Abstract

The present application belongs to the technical field of adsorbent materials, and particularly relates to a kind of amidoxime-based polymer adsorbent material and its preparation method and application.The present application uses tannic acid and tetrafluoro-p-xylylene dinitrile as raw materials, forms precursor polymer with three-dimensional network cross-linking structure through cross-linking reaction, introduces amidoxime group through amidoxime reaction, and obtains amidoxime-based polymer adsorbent material.The present application realizes high selective coordination capture of gold ions by introducing amidoxime group;in-situ reduction of gold ions is realized by using tannic acid phenolic hydroxyl group;high stability of the material under harsh environment is endowed by using fluorine-containing rigid cross-linking skeleton.The material can directly complete selective adsorption, in-situ reduction and elemental gold recovery of gold from complex electronic waste leaching liquor in one step, omits elution and additional reduction steps in traditional process, and has the advantages of simple process, high efficiency, good selectivity, low cost, green environmental protection and the like.

Description

Technical Field

[0001] This invention belongs to the field of adsorbent materials technology, specifically relating to a methylamine oxime-based polymer adsorbent material, its preparation method, and its application. Background Technology

[0002] With the rapid advancement of electronic devices, e-waste has become one of the fastest-growing solid wastes globally. E-waste contains a large amount of valuable precious metals, especially gold, with a much higher content than in natural ores. Therefore, the efficient recovery of gold from e-waste not only has enormous economic value but also plays a vital role in sustainable resource development and environmental protection.

[0003] In recent years, adsorbent materials have shown potential as adsorbents in improving the adsorption performance of gold ions in electronic waste leachate. Existing adsorbent materials are mainly divided into two categories based on their technical approaches: reduction-driven materials and coordination-driven materials. Reduction-driven materials are developed by introducing reducing functional groups or loading nano-metals to adsorb Au ions. 3+ Restore to Au 0 However, such materials overemphasize reducing power, often resulting in a significant decrease in selectivity due to non-specific reduction reactions, and the reduction process easily leads to oxidative dissolution or framework collapse of the material structure. Coordination-driven materials selectively capture gold ions through nitrogen / oxygen-containing coordinating groups, but can only achieve enrichment and separation, and cannot directly obtain elemental gold. They require subsequent elution and reduction steps, which is difficult to meet the needs of efficient industrial recycling.

[0004] Therefore, existing adsorption materials cannot simultaneously meet the requirements of high selective adsorption, in-situ efficient reduction, and structural stability, and cannot achieve the direct recovery of elemental gold products from complex leachates. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides a metallo-oxime-based polymer adsorbent material, its preparation method, and its applications. The metallo-oxime-based polymer adsorbent material prepared by this invention can selectively capture, reduce in situ, and recover elemental gold ions from electronic waste leachate in a single step; it eliminates the necessary elution and additional reduction steps required in traditional methods, directly recovering high-value-added elemental gold products from the leachate, significantly improving the efficiency, selectivity, and economy of the gold recovery process.

[0006] This invention utilizes fluorinated rigid benzene ring units and tannic acid to form a three-dimensional network cross-linked polymer, constructing a rigid hydrophobic framework, and introduces a methylamine oxime group to achieve specific recognition and efficient capture of gold ions. When the methylamine oxime group captures Au(III), the adjacent phenolic hydroxyl group can directly donate electrons, driving the in-situ reduction of Au(III) to elemental gold, achieving efficient in-situ reduction of Au(III). At the same time, the rigid hydrophobic framework endows the material with excellent structural stability and hydrophobicity, enabling it to withstand the harsh environment of electronic waste leachate and protecting the internal active groups from failure. This solves the problem that existing adsorbent materials cannot simultaneously meet the requirements of high selective adsorption, efficient in-situ reduction, and structural stability.

[0007] The first objective of this invention is to provide a metallo-oxime-based polymer adsorbent material, wherein the metallo-oxime-based polymer adsorbent material is prepared by cross-linking a precursor polymer with a three-dimensional network cross-linked structure formed by tannic acid and tetrafluoroterephthalonitrile through a cross-linking reaction, and then modifying it by a metallo-oxime reaction.

[0008] Preferably, the mass ratio of tannic acid to tetrafluoroterephthalonitrile is 1:0.5 to 1.

[0009] A second objective of this invention is to provide a method for preparing a amine oxime-based polymer adsorbent material, comprising the following steps:

[0010] Under a protective atmosphere and with alkaline catalysis, tannic acid and tetrafluoroterephthalonitrile are dissolved in a first solvent and heated to 90℃~110℃ for a crosslinking reaction to obtain a precursor polymer with a three-dimensional network crosslinking structure. The precursor polymer, organic base and hydroxylamine hydrochloride are dispersed in a second solvent and heated to 60℃~70℃ for a meramine oxime reaction to obtain a meramine oxime-based polymer adsorbent material.

[0011] Preferably, the mass ratio of tannic acid to alkali is 1:2.

[0012] Preferably, the mass ratio of the precursor polymer to hydroxylamine hydrochloride is 1:3. An excess of hydroxylamine hydrochloride is used to completely convert the cyano groups in the precursor polymer into amine oxime groups.

[0013] Preferably, the cross-linking reaction time is 10h to 14h.

[0014] Preferably, the alkali is potassium carbonate.

[0015] Preferably, the first solvent is a mixed solvent of tetrahydrofuran and N,N-dimethylformamide, wherein the volume ratio of tetrahydrofuran to N,N-dimethylformamide is 8:1.

[0016] Preferably, the mass ratio of the precursor polymer to the organic base is 1:2.

[0017] Preferably, the time for the oxime reaction is 20 h to 28 h.

[0018] Preferably, the organic base is triethylamine.

[0019] Preferably, the second solvent is ethanol.

[0020] The third objective of this invention is to provide an application of a amine oxime-based polymer adsorbent material in the adsorption and reduction of gold in gold-containing wastewater.

[0021] Preferably, the gold-containing wastewater is leachate from electronic waste.

[0022] The preferred and specific application methods are as follows:

[0023] A amine oxime-based polymer adsorbent material is added to gold-containing wastewater for adsorption. After adsorption, elemental gold is deposited on the surface of the material, and efficient gold recovery can be achieved through filtration.

[0024] Preferably, the concentration of the gold-containing wastewater is 50 mg / L to 1200 mg / L, and the ratio of the amount of the metallo-oxime polymer adsorbent to the gold-containing wastewater is 1 mg: 1 mL to 4 mL.

[0025] Compared with the prior art, the present invention has the following technical effects:

[0026] 1. This invention uses tannic acid and tetrafluoroterephthalonitrile as raw materials. A precursor polymer with a three-dimensional network cross-linked structure is formed by the cross-linking reaction of tannic acid and tetrafluoroterephthalonitrile, thus constructing a rigid hydrophobic framework. A methylamine oxime group is introduced onto the precursor polymer through a methylamine oxime reaction. The methylamine oxime group has a strong coordination ability and specificity for Au, thus achieving highly selective coordination capture of gold ions. At the same time, after the tannic acid phenolic hydroxyl group captures gold ions, the adjacent phenolic hydroxyl group can provide electrons to directly drive the in-situ reduction of Au(III) to elemental gold, thereby achieving in-situ reduction of the captured gold ions. Furthermore, the constructed rigid hydrophobic framework endows the material with high stability under harsh environments, enabling it to withstand the harsh environment of electronic waste leachate and protecting the internal active groups from failure.

[0027] 2. The amylopyridine-oxime-based polymer adsorbent material prepared by this invention can directly and in one step achieve selective adsorption, in-situ reduction and elemental gold recovery from complex electronic waste leachate, realizing the integration of "capture-reduction", omitting the elution and additional reduction steps in traditional processes, and has the advantages of simple process, high efficiency, good selectivity, low cost and green environmental protection.

[0028] 3. This invention utilizes the nitrogen and oxygen atoms on the metallo-oxime group as strong coordination sites to form stable coordination bonds with gold ions, achieving highly selective adsorption of gold even in the presence of numerous coexisting ions. This invention utilizes natural and inexpensive tannic acid as both a framework component and a source of reducing agent, making the process environmentally friendly and cost-effective. This invention uses tetrafluoroterephthalonitrile as a crosslinking agent; the fluorinated rigid crosslinked framework endows the material with exceptional stability, enabling it to maintain structural and performance integrity for extended periods in strong acid and high-salt environments, resulting in a long service life. Attached Figure Description

[0029] Figure 1 The images show SEM images of the TA-PAO adsorbent material prepared in Example 1 at different magnifications. Among them, (a) is the SEM image at a magnification of 300 nm; and (b) is the SEM image at a magnification of 10 μm.

[0030] Figure 2 The TA-PAO adsorbent material prepared in Example 1 adsorbs Au. 3+ The following are the SEM and EDS images. Among them, (a) is the SEM image; (b) is the Au element distribution image; (c) is the O element distribution image; (d) is the C element distribution image; (e) is the F element distribution image; and (f) is the N element distribution image.

[0031] Figure 3 The image shows the adsorption kinetics curve of the TA-PAO adsorbent material prepared in Example 1; the inset is an enlarged view of the horizontal axis from 0 to 10 min.

[0032] Figure 4 The TA-CN adsorbent material prepared in Comparative Example 1 and the TA-PAO adsorbent material prepared in Example 1 were used to assess the adsorption of Au. 3+ Adsorption comparison diagram of ions.

[0033] Figure 5 The image shows the isothermal adsorption curve of the TA-PAO adsorbent material prepared in Example 1.

[0034] Figure 6 The graph shows the adsorption capacity of the TA-PAO adsorbent material prepared in Example 1 under different pH conditions.

[0035] Figure 7 To illustrate the effect of TA-PAO adsorbent material prepared in Example 1 on Au in the presence of coexisting ions. 3+ Selective adsorption chromatograms; insets are magnified chromatograms of Zn and Au at concentrations of 0–3 mg / g.

[0036] Figure 8 The image shows the adsorption of the TA-PAO adsorbent material prepared in Example 1 onto actual electronic waste leachate. Detailed Implementation

[0037] To enable those skilled in the art to better understand and implement the technical solutions of the present invention, the present invention will be further described below in conjunction with specific embodiments and accompanying drawings.

[0038] Unless otherwise specified, all reagents used in this invention are commercially available, and all methods used are conventional techniques in the art.

[0039] Example 1

[0040] A method for preparing a amine oxime-based polymer adsorbent material includes the following steps:

[0041] Step 1: Synthesize the precursor polymer:

[0042] Under a nitrogen atmosphere, 2 g of tannic acid, 1.4 g of tetrafluoroterephthalonitrile, and 4 g of potassium carbonate were dissolved in a mixed solvent of 80 mL of tetrahydrofuran and 10 mL of N,N-dimethylformamide. The resulting mixture was then stirred at 100 °C for 12 h to allow the fluorinated rigid benzene rings of tannic acid and tetrafluoroterephthalonitrile to crosslink and form a polymer. After the reaction was completed, the product was washed sequentially with 1 M HCl solution, deionized water, THF, and dichloromethane, and then dried under vacuum at 60 °C for 12 h to obtain a pale yellow precursor polymer, denoted as TA-CN.

[0043] Step 2: Preparation of a amine oxime-based polymer adsorbent material:

[0044] 1.0 g of TA-CN, 2 g of triethylamine and 3 g of hydroxylamine hydrochloride were dispersed in 100 mL of anhydrous ethanol and stirred at 65 °C for 24 h to carry out the amylopyroxylation reaction of the cyano group to introduce amylopyroxymethylene functional group. After the reaction was completed, the product was washed thoroughly with deionized water and ethanol in sequence, and then dried under vacuum at 60 °C for 12 h to obtain the amylopyroxymethylene polymer adsorbent material, denoted as TA-PAO.

[0045] Comparative Example 1

[0046] A method for preparing a polymer adsorbent material includes the following steps:

[0047] The difference from Example 1 is as follows:

[0048] The precursor polymer did not incorporate a amine oxime group.

[0049] Under a nitrogen atmosphere, 2 g of tannic acid, 1.4 g of tetrafluoroterephthalonitrile, and 4 g of potassium carbonate were dissolved in a mixed solvent of 80 mL of tetrahydrofuran and 10 mL of N,N-dimethylformamide. The resulting mixture was then stirred at 100 °C for 12 h to allow the fluorinated rigid benzene rings of tannic acid and tetrafluoroterephthalonitrile to crosslink and form a polymer. After the reaction was completed, the product was washed sequentially with 1 M HCl solution, deionized water, THF, and dichloromethane, and then dried under vacuum at 60 °C for 12 h to obtain a pale yellow precursor polymer, denoted as TA-CN.

[0050] Experimental test:

[0051] 1. SEM test.

[0052] like Figure 1 As shown, the TA-PAO adsorbent material prepared in Example 1 is an irregular porous structure formed by stacking closely arranged two-dimensional nanosheets with a particle size between 10 μm and 50 μm.

[0053] from Figure 2 The combination of SEM and EDS mapping clearly shows that Au 3+ It is adsorbed onto the TA-PAO adsorbent material and reduced to 2μm gold elemental particles.

[0054] 2. Adsorption test.

[0055] Preparation of adsorption solution:

[0056] Au 3+ The solution was prepared by dissolving HAuCl4 in ultrapure water. 3.4502 g of HAuCl4 was dissolved in 1 L of ultrapure water by ultrasonication to obtain a 2 g / L Au solution. 3+ Stock solutions; dilute 2 g / L stock solutions with deionized water to obtain Au concentrations of different concentrations. 3+ Solution. Au in water samples was determined using a continuous-light source atomic absorption spectrometer. 3+ Concentration, used to evaluate the adsorbent's effect on Au. 3+ The adsorption effect was measured. All experiments were conducted three times, and the final data was the average of the three experiments.

[0057] Adsorption kinetics:

[0058] 100 mg of the TA-PAO adsorbent material prepared in Example 1 was added to 200 mL of Au solutions with concentrations of 20 mg / L, 50 mg / L, and 100 mg / L, respectively. 3+The solution was shaken in a constant-temperature shaking chamber at 180 rpm, and samples were taken sequentially at 0 min, 1 min, 2 min, 5 min, 7 min, 10 min, 15 min, 30 min, and 60 min. The samples were filtered through a 0.45 μm polyethersulfone membrane to obtain the supernatant, and the Au before and after adsorption was determined using a ContrAA 700 high-resolution continuous-source atomic absorption spectrometer. 3+ The concentration change.

[0059] like Figure 3 As shown, the TA-PAO adsorbent material can achieve adsorption of different concentrations of Au within 10 minutes. 3+ Au in solution 3+ With 99% ion recovery, it exhibits an ultra-fast adsorption rate.

[0060] Adsorption comparison test:

[0061] 10 mg of the TA-CN adsorbent prepared in Comparative Example 1 or the TA-PAO adsorbent prepared in Example 1 was added to 20 mL of Au solution with a concentration of 1200 mg / L. 3+ In the solution, the mixture was shaken at 303 K and 180 rpm in a constant-temperature shaking oven for 12 h. After adsorption equilibrium, the sample was filtered through a 0.45 μm polyethersulfone membrane to obtain the supernatant. The Au content of the supernatant was then analyzed. 3+ The concentration was measured.

[0062] like Figure 4 As shown, the TA-CN adsorbent material for Au 3+ The adsorption capacity of Au ions is only 440 mg / g; while the TA-PAO adsorbent material with the introduction of a amine oxime group has a higher adsorption capacity for Au ions. 3+ The adsorption capacity of ions was increased to 1064 mg / g; this indicates that the amylopyridine-based polymer adsorbent material prepared according to the embodiments of the present invention has a high adsorption capacity for Au. 3+ Ions have high adsorption capacity.

[0063] Adsorption test at different temperatures:

[0064] 15 mg of TA-PAO adsorbent was added to 30 mL of Au solution of different concentrations. 3+ In the solution, the experiments were conducted at different temperatures of 288 K, 303 K, and 318 K, and shaken for 12 hours in a constant-temperature shaking chamber at 180 rpm. Au in the adsorption solution... 3+The initial concentrations were in the ranges of 50 mg / L, 200 mg / L, 400 mg / L, 600 mg / L, 800 mg / L, 1000 mg / L, and 1200 mg / L. After adsorption equilibrium was reached, the samples were filtered through a 0.45 μm polyethersulfone membrane to obtain the supernatant. The Au content before and after adsorption was determined using a ContrAA 700 high-resolution continuous-source atomic absorption spectrometer. 3+ The concentration change.

[0065] like Figure 5 As shown, the TA-PAO adsorbent material for Au 3+ The adsorption capacity of ions increases with increasing temperature, reaching a maximum adsorption capacity of 1236 mg / g, demonstrating a high adsorption capacity.

[0066] Adsorption tests under different pH conditions:

[0067] Prepare 5 solutions of Au, each 50 mL in volume and with an initial concentration of 50 mg / L. 3+ Solution, Au 3+ The pH of the solution was adjusted sequentially to 1, 2, 3, 4, 5, 6, and 7; 50 mL of Au solutions at different pH values ​​were added. 3+ 25 mg of TA-PAO adsorbent was added to the solution for adsorption. The mixture was shaken at a constant speed of 180 rpm for 1 hour in a constant-temperature shaker at 303 K. After adsorption equilibrium was reached, the supernatant was collected by filtration through a pinhole membrane. Au was measured before and after adsorption using a ContrAA 700 high-resolution continuous-wave atomic absorption spectrometer. 3+ The concentration changes were used to evaluate the adsorption effect under different pH conditions.

[0068] like Figure 6 As shown, the TA-PAO adsorbent material exhibits good adhesion to Au under strongly acidic conditions. 3+ The fact that it still has a good removal effect indicates that the adsorbent material is acid-resistant and has a wide range of applications.

[0069] Selective adsorption test:

[0070] Add 50 mg of TA-PAO adsorbent material to 100 mL of Cu. 2+ Ni 2+ Ca 2+ Pb 2+ K + Cd 2+ Zn 2+ Co 2+ and Au 3+The solution was prepared with 9 ions at a concentration of 100 mg / L. Then, it was shaken in a constant temperature shaking oven at 30 °C for 12 h. After adsorption equilibrium was reached, the supernatant was collected by filtration through a needle filter. The concentration of each component ion in the supernatant was determined by the original absorption spectrum of a ContrAA 700 high resolution continuous light source.

[0071] like Figure 7 As shown, TA-PAO adsorbent material can adsorb Au in a mixed solution. 3+ The selective separation from other metal ions indicates that the TA-PAO adsorbent material has excellent selectivity for Au3+ in complex mixed solutions containing gold ions.

[0072] 3. Application of adsorption in actual samples.

[0073] Gold extraction using real electronic waste:

[0074] 1.73g of pins were collected from a spent CPU using a hot air gun and added to 100mL of N-bromosuccinimide / pyridine solution. After shaking in a 30℃ constant temperature shaking incubator for 12h, the supernatant was collected by filtration. The pH of the supernatant was adjusted to 3 with dilute hydrochloric acid to obtain the spent CPU pin leachate. 100mg of TA-PAO adsorbent was added to 100mL of the spent CPU pin leachate. After shaking in a 30℃ constant temperature shaking incubator for 24h, the supernatant was collected by filtration through a pinhole filter membrane. The concentration of each component ion in the supernatant was determined using a ContrAA 700 high-resolution continuous light source original absorption spectrum.

[0075] like Figure 8 As shown, the selective recovery of gold by TA-PAO adsorbent material in actual electronic waste leachate demonstrates the great potential of TA-PAO adsorbent material in practical applications.

[0076] It should be noted that when numerical ranges are involved in this invention, it should be understood that the two endpoints of each numerical range, as well as any value between the two endpoints, can be selected. Since the steps and methods used are the same as in the embodiments, preferred embodiments are described in this invention to avoid redundancy. Although preferred embodiments of this invention have been described, those skilled in the art, once they understand the basic inventive concept, can make other changes and modifications to these embodiments, and all such changes and modifications fall within the scope of this invention.

[0077] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. If these modifications and variations fall within the scope of equivalents of this invention, then this invention also intends to include these modifications and variations.

Claims

1. A geminal amine oxime-based polymer adsorbent material, characterized in that, The amylopyridine-based polymer adsorbent material is prepared by cross-linking a precursor polymer with a three-dimensional network cross-linked structure formed by tannic acid and tetrafluoroterephthalonitrile, followed by amylopyridine modification.

2. The geminal oxime-based polymer adsorbent material according to claim 1, characterized in that, The mass ratio of tannic acid to tetrafluoroterephthalonitrile is 1:0.5 to 1.

3. A method for preparing the geminal oxime-based polymer adsorbent material according to claim 1 or 2, characterized in that, Includes the following steps: Under a protective atmosphere and alkaline catalysis, tannic acid and tetrafluoroterephthalonitrile are dissolved in a first solvent and heated to 90℃~110℃ for cross-linking reaction to obtain a precursor polymer with a three-dimensional network cross-linked structure. The precursor polymer, organic base and hydroxylamine hydrochloride are dispersed in a second solvent and heated to 60℃~70℃ for a meramine oxime reaction to obtain a meramine oxime-based polymer adsorbent material.

4. The method for preparing the geminal oxime-based polymer adsorbent material according to claim 3, characterized in that, The mass ratio of the precursor polymer to hydroxylamine hydrochloride is 1:3; the mass ratio of the precursor polymer to the organic base is 1:

2.

5. The method for preparing the geminal oxime-based polymer adsorbent material according to claim 3, characterized in that, The cross-linking reaction time is 10h to 14h; the oxime reaction time is 20h to 28h.

6. The method for preparing the geminal oxime-based polymer adsorbent material according to claim 3, characterized in that, The mass ratio of tannic acid to alkali is 1:

2.

7. The method for preparing the geminal oxime-based polymer adsorbent material according to claim 3, characterized in that, The first solvent is a mixture of tetrahydrofuran and N,N dimethylformamide, with a volume ratio of 8:1; the second solvent is ethanol.

8. An application of a amine oxime-based polymer adsorbent material in the adsorption and reduction recovery of gold from gold-containing wastewater, characterized in that, The amylopyridine-oxime polymer adsorbent material is the amylopyridine-oxime polymer adsorbent material as described in claim 1 or 2.

9. The application of the geminal oxime-based polymer adsorbent material according to claim 8 in the adsorption and reduction recovery of gold from gold-containing wastewater, characterized in that, The specific application methods are as follows: A amine oxime-based polymer adsorbent material is added to gold-containing wastewater for adsorption. After adsorption, elemental gold is deposited on the surface of the material, and efficient gold recovery can be achieved through filtration.

10. The application of the geminal oxime-based polymer adsorbent material according to claim 9 in the adsorption and reduction recovery of gold from gold-containing wastewater, characterized in that, The concentration of the gold-containing wastewater is 50 mg / L to 1200 mg / L, and the ratio of the amylopyridine polymer adsorbent to the gold-containing wastewater is 1 mg: 1 mL to 4 mL.

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