An electrospinning-based [Au(CN) 2 ] - Preparation method of selective separation imprinted nanofibers

Abstract

The present invention discloses a preparation method of selective separation imprinted nanofibers based on electrospinning of [Au(CN)2] ‑ which comprises the following steps: (1) uniformly mixing an imprinting functional monomer, sodium dicyanoaurate, a solvent, an electrospinning polymer monomer and an initiator, and then carrying out a polymerization reaction; the imprinting functional monomer includes 1,3-diallyl-2-thiourea; (2) carrying out electrospinning on the product obtained in step (1) to obtain nanofibers; (3) washing the nanofibers obtained in step (2) to remove [Au(CN)2] ‑ . The present invention also discloses the imprinted nanofibers obtained by using the above preparation method and their application in the selective separation of [Au(CN)2] ‑ . The present invention applies the electrospinning technology to the preparation of imprinted nanofibers, realizing the efficient and specific separation of [Au(CN)2] ‑ .

Description

Technical Field

[0001] The present invention belongs to the field of materials, and specifically relates to an electrospinning-based [Au(CN) 2 ] - Preparation method of selective separation imprinted nanofibers. Background Art

[0002] Cyanide metallurgy technology has always been one of the main methods for gold extraction by gold mining companies at home and abroad. Its main principle is that gold has good solubility in oxygen-containing cyanide solutions and can form relatively stable complex ions in the solution, which can achieve the purpose of gold extraction through reduction adsorption. A large amount of cyanide-containing wastewater will be produced during the cyanide gold extraction production process, such as cyanide barren solution, ore washing wastewater, tailings slurry, etc. The above wastewater contains rich valuable metal elements, such as gold, copper, iron, etc., most of which exist in the form of cyanide complexes; among them, gold is mainly in the form of [Au(CN) 2 ] - exists in the form of.

[0003] In the prior art, the methods for recovering valuable metals from cyanide-containing gold extraction wastewater can be divided into two categories: indirect recovery method and direct recovery method. The direct recovery method mainly includes the AVR method (acid recovery method) and its derivative methods such as sulfide precipitation method; the indirect recovery method is to first enrich cyanide or valuable components using resins, activated carbon, membranes or extractants, and then use the AVR method to recover valuable components. The above methods lack specific selectivity and are difficult to achieve [Au(CN) 2 ] - The specific recovery of the product is complex and the process is complicated; the extraction method requires the use of a large amount of organic reagents, which is not environmentally friendly.

[0004] Molecular Imprinting Technology (MIT) is a technology that uses molecular imprinting polymers to simulate the interaction between enzymes and substrates or antibodies and antigens to specifically recognize template molecules. Through the interaction between the template and the functional groups on the monomers, the monomers self-assemble around the template molecule to form molecular imprinting polymers (MIPs). Subsequently, the template is partially or completely removed, leaving a cavity that is complementary to the template in size and shape. The obtained cavity can serve as a selective binding site for the template molecule. The application of molecular imprinting technology is expected to solve the problem of [Au(CN) 2 ] - However, the existing molecular imprinting materials are basically in the form of particles or even powders, which have great flow resistance during the flow process and are not conducive to practical industrial applications. Summary of the invention

[0005] In view of the above-mentioned shortcomings of the prior art, the present invention provides an electrospinning-based [Au(CN)2 ] - The preparation method of selective separation imprinted nanofibers solves the problem of [Au(CN) 2 ] - The problem of specific separation and recovery.

[0006] The specific technical solutions are as follows:

[0007] One of the purposes of the present invention is to provide an electrospinning-based [Au(CN) 2 ] - A method for preparing selective separation imprinted nanofibers comprises the following steps:

[0008] (1) mixing an imprinting functional monomer, a dicyanohydride salt, a solvent, an electrospinning polymer monomer and an initiator, and then performing a polymerization reaction; the imprinting functional monomer comprises 1,3-diallyl-2-thiourea;

[0009] (2) using the product obtained in step (1) to perform electrospinning to obtain nanofibers;

[0010] (3) Wash the nanofibers obtained in step (2) to remove [Au(CN) 2 ] - , we get [Au(CN) 2 ] - Selective separation of imprinted nanofibers.

[0011] In the present invention, the imprinted functional monomer and [Au(CN) 2 ] - A functional monomer-template complex is formed; under the action of the initiator, the imprinted functional monomer and the electrospinning polymer monomer undergo a polymerization reaction to generate a polymer soluble in the solvent, which is then prepared into nanofibers by electrospinning. At this time, [Au(CN) 2 ] - It has been embedded into the surface of nanofibers. Then, by washing, the embedded [Au(CN) 2 ] - Remove it to leave an adsorption space.

[0012] Traditional imprinted materials are basically in the form of particles or even powders, which have large flow resistance during the flow process and are not conducive to practical industrial applications. The present invention applies electrospinning technology to the preparation of imprinted materials to obtain fibrous imprinted materials, thereby overcoming the above problems. In addition, most of the adsorption holes of the imprinted materials prepared by the present invention are located on the fiber surface, which has a faster adsorption rate.

[0013] In the present invention, 1,3-diallyl-2-thiourea is used as the imprinting functional monomer. Based on the hard-soft acid-base theory, the S in the imprinting functional monomer is combined with the Au ions in the template ions to form a complex. The structure is fixed by polymerization reaction, and then the template ions are removed to form an imprinting cavity.

[0014] Furthermore, in step (1), the dicyanohydrite salt is sodium dicyanohydrite (I).

[0015] Further, in step (1): 1,3-diallyl-2-thiourea and [Au(CN) 2 ] - The molar ratio is (3-5):1.

[0016] Furthermore, in step (1), the usage ratio of the imprinting functional monomer to the electrospinning polymer monomer is preferably (0.3-0.6) g:1 mL.

[0017] Furthermore, in step (1): the electrospinning polymer monomer is preferably at least one of acrylonitrile, vinylidene fluoride, and para-chloromethylstyrene.

[0018] Furthermore, in step (1): the solvent is preferably at least one of N,N-dimethylformamide and dimethyl sulfoxide.

[0019] Furthermore, in step (1): the initiator is preferably at least one of azobisisobutyronitrile and azobisisoheptanenitrile.

[0020] Furthermore, in step (1), the volume ratio of the solvent to the electrospinning polymer monomer is preferably (5-20):1.

[0021] Furthermore, in step (1), the polymerization reaction is preferably carried out at 50 to 90° C. for 4 to 48 hours, and more preferably at 60 to 80° C. for 8 to 15 hours.

[0022] Furthermore, in step (1): after mixing the components, ultrasonic treatment is preferably performed, preferably for 10 to 30 minutes.

[0023] Furthermore, in step (2): the electrospinning conditions are preferably at room temperature, with a voltage of 15 to 18 kV, a flow rate of 0.10 to 0.30 mL / min, and a receiving distance of 15 to 18 cm.

[0024] Furthermore, in step (3): the nanofibers are preferably washed with a sodium thiosulfate solution, wherein the concentration of the sodium thiosulfate solution is preferably 4 to 8 mol / L.

[0025] Further, in step (3): washing to remove [Au(CN) 2 ] -Afterwards, the nanofibers are dried. The preferred drying condition is drying in a vacuum drying oven at 30-70° C. for 4-24 hours.

[0026] The second object of the present invention is to provide [Au(CN) 2 ] - Selective separation of imprinted nanofibers.

[0027] The third object of the present invention is to provide the above-mentioned [Au(CN) 2 ] - Selective separation of imprinted nanofibers in [Au(CN) 2 ] - Application in selective separation. The nanofiber material of the present invention leaves behind a specific [Au(CN) 2 ] - Adsorption vacancies enables the [Au(CN) 2 ] - Highly efficient and specific separation.

[0028] The beneficial effects of the present invention are as follows:

[0029] The present invention applies electrospinning technology to [Au(CN) 2 ] - Preparation of selective separation imprinted nanofibers to achieve [Au(CN) 2 ] - The present invention applies electrospinning technology to the preparation of imprinted materials to obtain fibrous imprinted materials, which overcomes the problem of large flow resistance of traditional granular or powdered imprinted materials and is more suitable for industrial applications. The imprinted materials prepared by this method have a high specificity for [Au(CN) 2 ] - The maximum adsorption capacity can reach 76 mg / g, and the adsorption equilibrium time is within 5 min. 2 ] - It has excellent selectivity. The [Au(CN) 2 ] - Selective separation imprinted nanofibers can be used to specifically recover [Au(CN) 2 ] - . BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 The [Au(CN) 2 ] - SEM images of selectively separated imprinted nanofibers;

[0031] Figure 2The [Au(CN) 2 ] - IR spectra of selectively separated imprinted nanofibers;

[0032] Figure 3 In Example 1, [Au(CN) 2 ] - Selective separation of imprinted nanofibers adsorbed with [Au(CN) 2 ] - SEM image after ionization;

[0033] Figure 4 In Example 1, [Au(CN) 2 ] - Selective separation of imprinted nanofibers adsorbed with [Au(CN) 2 ] - After infrared spectrum. DETAILED DESCRIPTION

[0034] The principles and features of the present invention are described below in conjunction with examples, which are only used to explain the present invention and are not used to limit the scope of the present invention. The experimental methods used in the following examples are conventional methods unless otherwise specified. The materials, reagents, etc. used in the following examples, unless otherwise specified, can all be obtained from commercial sources.

[0035] Example 1

[0036] 1. Preparation of [Au(CN) 2 ] - Selectively separate the imprinted nanofibers as follows:

[0037] (1) Using 1,3-diallyl-2-thiourea and sodium dicyanoacrylate (I) as raw materials, weigh 0.62 g of 1,3-diallyl-2-thiourea and 0.272 g of sodium dicyanoacrylate (I) (control the reaction between 1,3-diallyl-2-thiourea and [Au(CN) 2 ] - The mixture was added with a mixed solution of 20 mL N,N-dimethylformamide, 1.8 mL acrylonitrile and 0.1 g azobisisobutyronitrile, ultrasonicated for 10 min, and then reacted at 80° C. for 12 h to allow polymerization to occur;

[0038] (2) using the product obtained in step (1) to perform electrospinning, the operating conditions are: at room temperature, voltage 16 kV, flow rate 0.15 mL / min, receiving distance 15 cm, to obtain nanofibers;

[0039] (3) The nanofibers obtained in step (2) were thoroughly washed with 6 mol / L sodium thiosulfate solution to remove [Au(CN)2 ] - After that, it was placed in a vacuum drying oven at 50°C and dried for 8 h to obtain [Au(CN) 2 ] - Ion-imprinted nanofibers with specific selectivity.

[0040] The SEM images of the obtained ion-imprinted nanofibers are shown in Figure 1 As shown, the infrared spectrum is Figure 2 shown.

[0041] The adsorption of [Au(CN) 2 ] - The adsorption performance of [Au(CN) 2 ] - The maximum adsorption capacity is 76 mg / g and the adsorption equilibrium time is 5 min.

[0042] 2. Use the ion-imprinted nanofibers obtained by the above method to carry out [Au(CN) 2 ] - Selectively recovered, its composition is shown in Table 1.

[0043] Table 1

[0044] Element <![CDATA[[Au(CN) 2 ] - ]]> <![CDATA[[Cu(CN) 4 ] 2- ]]> <![CDATA[[Zn(CN) 4 ] 2- ]]> <![CDATA[[Fe(CN) 6 ] 3- ]]> Content (mg / L) 0.77 48.21 84.83 153.4

[0045] The experimental method is as follows: 2.0 g of the ion-imprinted nanofibers prepared by the above method were weighed and placed in an adsorption column with a diameter of 10 mm and a height of 100 mm. The flow rate was controlled to be 0.5 mL / min by a peristaltic pump, and the sample volume was 3000 mL. After the water sample treatment was completed, the composition of the effluent was shown in Table 2. The SEM image of the ion-imprinted nanofibers after adsorption is shown in Table 2. Figure 3 As shown, the infrared spectrum is Figure 4 shown.

[0046] Table 2

[0047] Element <![CDATA[[Au(CN) 2 ] - ]]> <![CDATA[[Cu(CN) 4 ] 2- ]]> <![CDATA[[Zn(CN) 4 ] 2- ]]> <![CDATA[[Fe(CN) 6 ] 3- ]]> Content (mg / L) 0 47.97 84.64 153.2

[0048] Then, 5 mL of 6 mol / L sodium thiosulfate solution was used as the desorption solution to determine [Au(CN) 2 ] - The concentration is 460 mg / L, of which [Au(CN) 2 ] - The content exceeds 98.4%.

[0049] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A novel electrospinning-based [Au(CN) 2 ] - Method for preparing selective separation imprinted nanofibers, It is characterized in that The steps include: (1) mixing an imprinting functional monomer, a dicyanohydride salt, a solvent, an electrospinning polymer monomer and an initiator, and then performing a polymerization reaction; the imprinting functional monomer comprises 1,3-diallyl-2-thiourea; the electrospinning polymer monomer is at least one of acrylonitrile, vinylidene fluoride and p-chloromethylstyrene; (2) using the product obtained in step (1) to perform electrospinning to obtain nanofibers; (3) Wash the nanofibers obtained in step (2) to remove [Au(CN) 2 - , and obtain [Au(CN) 2 - Selectively separate the imprinted nanofibers.​​ 2. The preparation method according to claim 1, It is characterized in that In step (1): the dicyanohydrite salt is sodium dicyanohydrite (I).

3. The preparation method according to claim 1, It is characterized in that In step (1): 1,3-diallyl-2-thiourea and [Au(CN) 2 ] - The molar ratio is (3-5):

1.

4. The preparation method according to claim 1, It is characterized in that In step (1): the usage ratio of the imprinting functional monomer to the electrospinning polymer monomer is (0.3-0.6) g:1 mL.

5. The preparation method according to claim 1, It is characterized in that In step (1): The solvent is at least one of N,N-dimethylformamide and dimethyl sulfoxide; The initiator is at least one of azobisisobutyronitrile and azobisisoheptanenitrile.

6. The preparation method according to claim 1, It is characterized in that In step (1): the volume ratio of the solvent to the electrospinning polymer monomer is (5-20):

1.

7. The preparation method according to claim 1, It is characterized in that In step (1): the polymerization reaction is carried out at 50-90° C. for 4-48 hours.

8. The preparation method according to claim 1, It is characterized in that In step (3): the nanofibers are washed with a sodium thiosulfate solution.

9. A novel electrospinning-based [Au(CN) 2 ] - Selectively separate imprinted nanofibers, obtained using the preparation method described in any one of claims 1 to 8.

10. An electrospinning-based [Au(CN) 2 ] - Selective separation of imprinted nanofibers in [Au(CN) 2 ] - Applications in selective separation.

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