Mercury ion imprinted membrane as well as preparation method and application thereof
By loading the mercury ion blot material with allylthiourea and methanol, acetonitrile and other materials on the PVDF film, a high selectivity and high stability mercury ion blot film is solved, and the low adsorption amount of mercury ion in the prior art is solved. The complex preparation process has achieved efficient mercury ion separation and environmentally friendly use effects.
Patent Information
- Application Number
- CN202411363816.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-28
- Publication Date
- 2024-12-13
AI Technical Summary
The adsorption of mercury ions by existing ion-blotting materials is relatively low, the preparation process is cumbersome, and the granular materials are not easy to recover after use, which easily causes environmental pollution, and have small particle size and poor dispersion.
Using PVDF film as the material matrix, allylthiourea as the functional monomer, and methanol and acetonitrile as the two-component solvent, the mercury ion-blotting material is loaded onto the PVDF film by ion blotting to form high selectivity and high stability mercury ion blot film.
It has achieved efficient selective separation of mercury ions, with an adsorption amount of 5000μg/g, a simple elution process and good application prospects for the material.
Smart Images
Figure CN119114032A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of heavy metal treatment, and in particular relates to a mercury ion imprinted membrane and a preparation method and application thereof. Background Art
[0002] Mercury ion is one of the most toxic heavy metal ions. Even at extremely low concentrations, it may cause serious health problems. At present, mercury and its compounds, as a valuable metal resource, are still used in many industrial processes, such as thermal power plants, cement kilns, chlor-alkali plants, and non-ferrous metal industries. With the improvement of equipment technology, the emission of atmospheric mercury has been significantly controlled, but a large amount of mercury is transferred to wastewater. Therefore, the treatment of mercury-containing wastewater is an important way to control Hg 2+ The key to release into the natural environment.
[0003] Ion imprinted membranes are prepared by coupling membrane separation technology and ion imprinting technology, using a membrane material with strong chemical stability as a solid support. Among them, membrane separation technology mainly relies on the difference in the magnitude of a certain force at both ends of the membrane to generate a driving force, and relies on the osmotic effect of the membrane to separate different components in the liquid. The source of the driving force may be the pressure difference, potential difference or concentration difference on both sides of the membrane. It is widely used in water treatment processes, such as seawater desalination, precise separation of molecules or ions, oil-water separation, etc. Ion imprinting technology uses ions as templates, and self-assembles ions with functional monomers through hydrogen bonds, chelation, etc. to form prepolymers; then cross-linking agents are used to obtain ion imprinted polymers, and finally the template ions are removed by acid washing, etc., and the resulting polymer surface forms imprinted holes that have both specific recognition and selectivity for the template ions. However, the current ion imprinted materials have the problems of low adsorption capacity, cumbersome preparation process, difficult recovery of granular ion imprinted materials after use, great loss after multiple uses, high possibility of causing environmental pollution during use, small particle size of granular ion imprinted materials, and poor dispersibility.
[0004] Therefore, how to provide an environmentally friendly ion-imprinted material with good adsorption of mercury ions and a simple preparation method is a technical problem that technical personnel in this field urgently need to solve. Summary of the invention
[0005] In order to solve the above technical problems, the present invention proposes a mercury ion imprinted membrane and a preparation method and application thereof.
[0006] To achieve the above object, the present invention provides the following technical solutions:
[0007] A method for preparing a mercury ion imprinted membrane, using a PVDF membrane as a material matrix, allylthiourea as a functional monomer, methanol as a polar porogen, and an ion imprinting method to load the mercury ion imprinted material onto the PVDF membrane to obtain the mercury ion imprinted membrane.
[0008] Preferably, the method specifically comprises the following steps:
[0009] The mercury salt was mixed with a mixed solution of methanol and acetonitrile, and then allyl thiourea, EGDMA and AIBN were added in sequence and mixed evenly, and then a PVDF membrane was added and nitrogen was introduced to carry out polymerization reaction in a water bath. After the reaction was completed, the Hg 2+ The mercury ion imprinted membrane is obtained by eluting, washing with water and then drying.
[0010] Preferably, before adding EGDMA and AIBN, the following steps are also included: adding a PVDF membrane and oscillating at room temperature, and then taking out the PVDF membrane after the oscillation is completed. Taking out the PVDF membrane is conducive to the uniform mixing of EGDMA and AIBN. That is, the mercury salt is mixed evenly with the mixed solution of methanol and acetonitrile, and then allyl thiourea is added and mixed evenly, and then the PVDF membrane is added and oscillated at room temperature. After the oscillation is completed, the PVDF membrane is taken out, EGDMA and AIBN are added and mixed evenly, and then the taken out PVDF membrane is added and nitrogen is introduced, and a polymerization reaction is carried out in a water bath. After the reaction is completed, the Hg on the obtained PVDF membrane loaded with ion imprinting material is removed. 2+ The mercury ion imprinted membrane is obtained by eluting, washing with water and then drying.
[0011] Beneficial effects: The ion-imprinted membrane has high selectivity, high stability, is conducive to continuous operation, does not require grinding operation, and can achieve efficient selective separation of target ions. The present invention uses methanol as a porogen and is mixed with acetonitrile as a two-component solvent. Allyl thiourea is used as a functional monomer, azobisisobutyronitrile (AIBN) is used as an initiator, and ethylene glycol dimethacrylate (EGDMA) is used as a crosslinking agent to prepare a mercury ion-imprinted membrane that can separate Hg 2+ It is highly selective, easy to elute, has a fast adsorption speed and good application prospects.
[0012] Preferably, the mercury salt is Hg(NO3)2 and / or HgCl2.
[0013] The pore size of the PVDF membrane is 0.22 μm or 0.45 μm.
[0014] Preferably, the volume ratio of methanol to acetonitrile in the mixed solution of methanol and acetonitrile is 1:1, and the ratio of the mercury salt to the mixed solution is 1 mmol:5 mL:5 mL.
[0015] Beneficial effects: The composition, ratio and volume of the solvent can be changed appropriately, but this change will affect the surface agent, pore size and Hg 2+ The effect of cavity formation.
[0016] Preferably, the uniform mixing is to dissolve and homogenize the substances in the system by using ultrasound and / or oscillation.
[0017] Preferably, the AIBN and Hg in the mercury salt 2+ The molar ratio is (1-1.5):(1-2).
[0018] Preferably, the allylthiourea, EGDMA and Hg in the mercury salt 2+ The molar ratio is 4:20:1.
[0019] Preferably, the temperature of the water bath is 60-70°C and the time is 10 min-24 h.
[0020] Preferably, the polymerization reaction process also includes a reflux stirring process.
[0021] The elution solution is a mixed solution of 0.5% thiourea and 0.5 mol / L HNO3.
[0022] Thiourea and HNO3 may be used in other proportions according to actual conditions, or HNO3 mixed solution may be used alone, but the elution effect cannot reach the best.
[0023] Beneficial effects: The solvents in the present invention are methanol and acetonitrile, both of which are polar solvents that can dissolve a variety of monomers, cross-linking agents and template molecules well, so that the reactants are fully mixed and the reaction efficiency is improved. Secondly, the EGDMA in the present invention forms a stable three-dimensional network structure in the polymer matrix through a cross-linking reaction, which can fix the interaction between the template ion and the functional monomer in the polymer matrix, thereby forming specific recognition sites. These recognition sites can efficiently rebind with the target ion after the template ion is removed. In addition, the allyl thiourea in the present invention enhances the selectivity for the target ion through the interaction between its thiourea group and the template ion. These specific interactions make the imprinted polymer have higher selectivity and affinity for the template ion or similar ions.
[0024] The microscopic working principle of the present invention is that the template ion and the functional monomer form a complex through electrostatic, coordination bonding and other methods. Under the action of an initiator (such as AIBN), the functional monomer and the cross-linking agent (such as EGDMA) form a three-dimensional network structure through free radical polymerization, which surrounds and fixes the template ion. After the polymer is formed, the template ion is removed by elution and other methods, leaving holes or recognition sites that match the shape and chemical environment of the template ion. These holes can specifically recognize and bind to the target ion, achieving highly selective and high-affinity adsorption and recognition.
[0025] A method for preparing a mercury ion imprinted membrane provides a mercury ion imprinted membrane.
[0026] The invention discloses an application of a mercury ion imprinted membrane in adsorbing mercury ions.
[0027] Compared with the prior art, the present invention has the following advantages and technical effects:
[0028] Allylthiourea was used as the functional monomer, PVDF membrane was used as the material matrix, and methanol and acetonitrile were used as the dual solvents. Methanol solvent was a polar porogen, which was conducive to dissolving Hg 2+ Acetonitrile as a non-protonic polar solvent can produce large pores and high surface area. The mercury ion imprinted material is loaded on the PVDF membrane by ion imprinting, which has good adsorption capacity for mercury, fast adsorption rate, and simple and easy elution process. The mercury ion imprinted membrane obtained by the present invention has good adsorption capacity for Hg 2+ It has good adsorption capacity and fast adsorption ability, and can reach an adsorption capacity of 5000μg / g, and Hg 2+ The elution is fast and has certain application prospects. BRIEF DESCRIPTION OF THE DRAWINGS
[0029] The drawings constituting a part of the present application are used to provide a further understanding of the present application. The illustrative embodiments and descriptions of the present application are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:
[0030] Figure 1 This is a schematic diagram of the process flow of Example 1 of the present invention;
[0031] Figure 2 This is a schematic diagram of the process flow of Example 4 of the present invention;
[0032] Figure 3 The scanning electron microscope image of the mercury ion imprinted membrane obtained in Example 1-4;
[0033] Among them, (a) is Example 2; (b) is Example 3; (c) is Example 1; (d) is Example 4;
[0034] Figure 4 The adsorption kinetic curve of the mercury ion imprinted membrane obtained by the polymerization reaction for 60 min in Example 1;
[0035] Figure 5 This is the adsorption kinetics curve of the mercury ion imprinted membrane obtained in Example 4. DETAILED DESCRIPTION
[0036] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.
[0037] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.
[0038] The embodiment of the present invention provides a method for preparing a mercury ion imprinted membrane, which uses a PVDF membrane as a material matrix, allyl thiourea as a functional monomer, and methanol as a polar porogen, and adopts an ion imprinting method to load the mercury ion imprinted material onto the PVDF membrane to obtain the mercury ion imprinted membrane.
[0039] In a preferred embodiment, the method specifically comprises the following steps:
[0040] The mercury salt was mixed with a mixed solution of methanol and acetonitrile, and then allyl thiourea, EGDMA and AIBN were added in sequence and mixed evenly, and then a PVDF membrane was added and nitrogen was introduced to carry out polymerization reaction in a water bath. After the reaction was completed, the Hg 2+ The mercury ion imprinted membrane is obtained by eluting, washing with water and then drying.
[0041] In a preferred embodiment, before adding EGDMA and AIBN, the following steps are also included: adding a PVDF membrane and shaking it at room temperature, and then taking out the PVDF membrane after the shaking is completed. Taking out the PVDF membrane is conducive to mixing EGDMA and AIBN evenly. That is, mercury salt is mixed evenly with a mixed solution of methanol and acetonitrile, and then allyl thiourea is added and mixed evenly, and then the PVDF membrane is added and shaken at room temperature, and then the PVDF membrane is taken out after the shaking is completed, and EGDMA and AIBN are added and mixed evenly, and then the taken out PVDF membrane is added and nitrogen is introduced, and a polymerization reaction is carried out under water bath conditions. After the reaction is completed, the Hg on the obtained PVDF membrane loaded with ion imprinting material is removed. 2+ The mercury ion imprinted membrane is obtained by eluting, washing with water and then drying.
[0042] The ion-imprinted membrane has high selectivity, high stability, is conducive to continuous operation, does not require grinding operation, and can achieve efficient selective separation of target ions. The present invention uses acetonitrile and methanol as dual solvents and porogens, allylthiourea as a functional monomer, AIBN as an initiator, and ethylene glycol dimethacrylate (EGDMA) as a crosslinking agent to prepare a mercury ion-imprinted membrane that can separate Hg 2+ It is highly selective, easy to elute, has a fast adsorption speed and good application prospects.
[0043] In a preferred embodiment, the mercury salt is Hg(NO3)2 and / or HgCl2.
[0044] The pore size of the PVDF membrane is 0.22 μm or 0.45 μm.
[0045] In a preferred embodiment, the volume ratio of methanol to acetonitrile in the mixed solution of methanol and acetonitrile is 1:1, and the ratio of the mercury salt to the mixed solution is 1mmol:5mL:5mL. The composition, ratio and volume of the solvent can be changed appropriately, but this change will affect the surface agent, pore size and Hg 2+ The effect of cavity formation.
[0046] In a preferred embodiment, the uniform mixing is to dissolve and homogenize the substances in the system by using ultrasound and / or oscillation.
[0047] In a preferred embodiment, the AIBN and Hg in the mercury salt 2+ The molar ratio is (1-1.5):(1-2).
[0048] In a preferred embodiment, the allylthiourea, EGDMA and Hg in the mercury salt 2+ The molar ratio is 4:20:1.
[0049] In a preferred embodiment, the temperature of the water bath is 60-70°C and the time is 10 min-24 h.
[0050] In a preferred embodiment, the polymerization process also includes a reflux stirring process.
[0051] The elution solution is a mixed solution of 0.5% thiourea and 0.5 mol / L HNO3.
[0052] Thiourea and HNO3 may be used in other proportions according to actual conditions, or HNO3 mixed solution may be used alone, but the elution effect cannot reach the best.
[0053] The embodiment of the present invention also provides a method for preparing a mercury ion imprinted membrane and a mercury ion imprinted membrane prepared therefrom.
[0054] The embodiment of the present invention also provides an application of a mercury ion imprinted membrane in adsorbing mercury ions.
[0055] Unless otherwise specified, the raw materials in the examples of the present invention were purchased from commercial sources.
[0056] The PVDF membrane used in the embodiments of the present invention was purchased from Beijing Xuanze Weiye Technology Co., Ltd., and has a pore size of 0.22 μm.
[0057] Example 1
[0058] A method for preparing a mercury ion imprinted membrane, such as Figure 1 As shown, the following steps are included:
[0059] Add 2 mmol of Hg(NO3)2 to the flask, then add a mixed solution of 10 mL of methanol and 10 mL of acetonitrile. After fully shaking the flask with the above solution at a speed of 150 r / min in an oscillating box, adjust the mixture according to the formula of allylthiourea:Hg 2+ Allyl thiourea was added in a molar ratio of 4:1, and after ultrasonication until the mixture was uniform, the PVDF membrane was added and oscillated for 2 h at room temperature. After the end, the PVDF membrane was taken out and then EGDMA:Hg 2+ EGDMA was added at a molar ratio of 20:1, and 1 mmol of AIBN was added at the same time. After oscillating in an oscillating box until the mixture was uniformly mixed, the PVDF membrane taken out earlier was added, and nitrogen was passed through the mixture under ice bath conditions for 10 to 20 minutes. Then, the polymerization reaction was carried out under heating in a 60°C water bath and oscillated at a speed of 120 r / min. After reacting for 60 minutes, the PVDF membrane loaded with ion-imprinted materials was taken out and washed with 0.5% thiourea + 0.5 mol / L HNO3 until there was no Hg 2+ Detection to remove Hg on the membrane 2+ The template ions are finally washed with pure water and dried at room temperature to obtain a mercury ion imprinted membrane.
[0060] Example 2
[0061] A method for preparing a mercury ion imprinted membrane comprises the following steps:
[0062] Add 2 mmol of Hg(NO3)2 to the flask, then add a mixed solution of 10 mL of methanol and 10 mL of acetonitrile. After fully shaking the flask with the above solution at a speed of 180 r / min in an oscillating box, adjust the mixture according to the formula of allylthiourea:Hg 2+ Allyl thiourea was added in a molar ratio of 4:1, and after ultrasonication until the mixture was uniform, the PVDF membrane was added and oscillated for 2 h at room temperature. After the end, the PVDF membrane was taken out and then EGDMA:Hg 2+ EGDMA was added at a molar ratio of 20:1, and 1 mmol of AIBN was added at the same time. After oscillating in an oscillating box until the mixture was uniformly mixed, the PVDF membrane taken out earlier was added, and nitrogen was passed through the mixture under ice bath conditions for 10 to 20 minutes. Then, the polymerization reaction was carried out under heating at 70°C water bath and oscillated at a speed of 120 r / min. After reacting for 10 minutes, the PVDF membrane loaded with ion-imprinted materials was taken out and washed with 0.5% thiourea + 0.5 mol / L HNO3 until there was no Hg 2+ Detection to remove Hg on the membrane 2+ The template ions are finally washed with pure water and dried at room temperature to obtain a mercury ion imprinted membrane.
[0063] Example 3
[0064] A method for preparing a mercury ion imprinted membrane comprises the following steps:
[0065] Add 2 mmol of Hg(NO3)2 to the flask, then add a mixed solution of 10 mL of methanol and 10 mL of acetonitrile. After fully shaking the flask with the above solution at a speed of 180 r / min in an oscillating box, adjust the mixture according to the formula of allylthiourea:Hg 2+ Allyl thiourea was added in a molar ratio of 4:1, and after ultrasonication until the mixture was uniform, the PVDF membrane was added and oscillated for 1 h at room temperature. After the mixture was finished, the PVDF membrane was taken out and then EGDMA:Hg 2+ EGDMA was added at a molar ratio of 20:1, and 1.5 mmol of AIBN was added at the same time. After oscillating in an oscillating box until the mixture was uniformly mixed, the PVDF membrane taken out earlier was added, and nitrogen was passed through the mixture under ice bath conditions for 10 to 20 minutes. Then, the polymerization reaction was carried out under heating at 70°C water bath and oscillated at a speed of 120 r / min. After the reaction for 30 minutes, the PVDF membrane loaded with ion-imprinted materials was taken out and washed with 0.5% thiourea + 0.5 mol / L HNO3 until there was no Hg 2+ Detection to remove Hg on the membrane 2+ The template ions are finally washed with pure water and dried at room temperature to obtain a mercury ion imprinted membrane.
[0066] Example 4
[0067] A method for preparing a mercury ion imprinted membrane, such as Figure 2 As shown, the following steps are included:
[0068] Add 2mmol Hg(NO3)2 to the flask, then add a mixed solution of 10mL methanol and 10mL acetonitrile, shake the flask containing the above solution in an oscillating box at a speed of 150-180r / min, and then adjust the mixture according to the formula of allylthiourea:Hg 2+ Allyl thiourea was added in a molar ratio of 4:1, and ultrasonication was performed until the mixture was uniform. Then EGDMA:Hg 2+ EGDMA was added to the solution at a molar ratio of 20:1, and 1.5 mmol AIBN was added at the same time. After oscillating in an oscillating box until the mixture was uniformly mixed, a PVDF membrane was added, and nitrogen was passed through the solution under ice bath conditions for 15 min. Then, the solution was heated in a water bath at 60°C and refluxed with a reflux device and stirred for 24 h. The PVDF membrane loaded with ion-imprinted materials was taken out and washed with 0.5% thiourea + 0.5 mol / L HNO3 until there was no Hg. 2+ Detect and remove Hg on the membrane 2+ The template ions are finally washed with pure water and dried at room temperature to obtain a mercury ion imprinted membrane.
[0069] Comparative Example 1
[0070] A method for preparing a mercury ion imprinted membrane, which is different from that of Example 1 in that the method comprises the steps of: 2+ Allyl thiourea was added in a molar ratio of 2:1, and the other process steps and parameters were the same as those in Example 1.
[0071] Comparative Example 2
[0072] A method for preparing a mercury ion imprinted membrane is different from that in Example 1 in that EGDMA is added at a molar ratio of EGDMA:Hg2+ of 10:1, and other process steps and parameters are the same as those in Example 1.
[0073] Comparative Example 3
[0074] A method for preparing a mercury ion imprinted membrane is different from that in Example 1 in that the eluent 0.5% thiourea+0.5 mol / L HNO3 is replaced by an equal amount of 0.5 mol / L HCl, and the other process steps and parameters are the same as those in Example 1.
[0075] Comparative Example 4
[0076] A method for preparing a mercury ion imprinted membrane is different from that in Example 1 in that the eluent 0.5% thiourea+0.5 mol / L HNO3 is replaced by an equal amount of 0.2 mol / L HNO3, and the other process steps and parameters are the same as those in Example 1.
[0077] Comparative Example 5
[0078] A method for preparing a mercury ion imprinted membrane is different from that in Example 1 in that the eluent 0.5% thiourea+0.5 mol / L HNO3 is replaced by an equal amount of 0.5 mol / L HNO3, and the other process steps and parameters are the same as those in Example 1.
[0079] Comparative Example 6
[0080] A method for preparing a mercury ion imprinted membrane is different from that in Example 1 in that the eluent 0.5% thiourea+0.5 mol / L HNO3 is replaced by an equal amount of 1 mol / L HNO3, and the other process steps and parameters are the same as those in Example 1.
[0081] Technical effect:
[0082] Performance Characterization
[0083] The scanning electron microscope images of the mercury ion imprint obtained in Examples 1-4 are as follows: Figure 3 As shown, it can be seen that: with the increase of polymerization time, the ion imprinted materials formed on the PVDF membrane gradually increase and are interwoven in the pore structure of the PVDF membrane.
[0084] Adsorption kinetics experiments
[0085] Prepare Hg at concentrations of 1mg / L, 3mg / L, 5mg / L, and 10mg / L 2+ solution, take 50 mL of the solution and add them into conical flasks respectively, add 100 mg of the mercury ion imprinted membrane obtained in Example 1 to the solution, and oscillate at 180 r / min, take samples at 5 min, 10 min, 20 min, 30 min, 60 min, 120 min, 240 min, 360 min, 480 min, 600 min and 960 min respectively, determine the adsorption capacity, and draw the adsorption kinetics curve.
[0086] The results are as follows Figure 4 As shown in FIG. 1 , it can be seen that the mercury ion imprinted membrane obtained in Example 1 of the present invention has a good adsorption effect on mercury ions, and the higher the concentration of the mercury ion solution, the higher the adsorption amount of mercury ions. 2+ When the solution concentration was 10 mg / L, the adsorption amount reached more than 1500 μg / g after 600 min of adsorption. 2+ At the concentration, the ion-imprinted membrane has a 2+ The adsorption capacity of Hg increases with the increase of adsorption time. It shows a faster adsorption capacity in the initial stage of adsorption and gradually slows down with the increase of time. The higher the initial concentration, the higher the adsorption capacity of Hg 2+ The larger the adsorption amount, the highest adsorption amount reaches 1600μg / g.
[0087] Prepare Hg at concentrations of 10mg / L and 20mg / L 2+ solution, take 50 mL of the solution and add them into conical flasks respectively, add 100 mg of the mercury ion imprinted membrane obtained in Example 4 to the solution, and oscillate at 180 r / min, take samples at 5 min, 10 min, 20 min, 30 min, 60 min, 120 min, 240 min, 360 min, 480 min, 600 min and 960 min respectively, determine the adsorption capacity, and draw the adsorption kinetics curve.
[0088] The results are as follows Figure 5 As shown in the figure, it can be seen that after 100 minutes of adsorption, the adsorption amount of the mercury ion imprinted membrane obtained by the present invention tends to be stable. 2+ The solution adsorption capacity reaches more than 4000μg / g, for Hg concentration of 20mg / L 2+ The solution adsorption capacity reaches over 5000 μg / g.
[0089] After adsorption for 100 min, the mercury ion imprinted membranes obtained in Example 1 and Comparative Examples 1-2 were effective for Hg 2+ The adsorption capacity of the solution is shown in Table 1:
[0090] Table 1
[0091]
[0092]
[0093] It can be seen that the present invention can achieve the highest adsorption capacity by adjusting the ratio of template ions, functional monomers and cross-linking agents.
[0094] The elution effects of Example 1 and Comparative Examples 3-6 were tested, and the results are shown in Table 2:
[0095] Table 2
[0096] Eluent Elution effect (%) Example 1 >98 Comparative Example 3 ～60 Comparative Example 4 ～65 Comparative Example 5 ～80 Comparative Example 6 ～70
[0097] It can be seen that the eluent selected in the present invention is a 0.5% thiourea + 0.5mol / L HNO3 mixed solution, which has a good elution effect. Using HNO3 solution alone or using hydrochloric acid solution can also achieve a certain elution effect, but it is significantly lower than the elution effect obtained by using 0.5% thiourea + 0.5mol / L HNO3 mixed solution as the eluent in the present invention.
[0098] The above are only preferred specific implementations of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.
Claims
1. A method for preparing a mercury ion imprinted membrane, characterized in that: With PVDF membrane as material matrix, allylthiourea as functional monomer and methanol as polar porogen, the mercury ion imprinting material is loaded onto the PVDF membrane by ion imprinting method to obtain mercury ion imprinted membrane.
2. The method for preparing a mercury ion imprinted membrane according to claim 1, characterized in that: The specific steps include: The mercury salt was mixed with a mixed solution of methanol and acetonitrile, and then allyl thiourea, EGDMA and AIBN were added in sequence and mixed evenly, and then a PVDF membrane was added and nitrogen was introduced to carry out polymerization reaction in a water bath. After the reaction was completed, the Hg 2+ The mercury ion imprinted membrane is obtained by eluting, washing with water and then drying.
3. The method for preparing a mercury ion imprinted membrane according to claim 2, characterized in that: Before adding EGDMA and AIBN, the following steps are also included: adding the PVDF membrane and shaking it at room temperature, and then taking out the PVDF membrane after the shaking is completed.
4. The method for preparing a mercury ion imprinted membrane according to claim 2, characterized in that: The volume ratio of methanol to acetonitrile in the mixed solution of methanol and acetonitrile is 1:1, and the ratio of the added amount of the mixed solution to the mercury salt is 1 mmol:5 mL:5 mL.
5. The method for preparing a mercury ion imprinted membrane according to claim 2 or 3, characterized in that: The AIBN and Hg in mercury salt 2+ The molar ratio is (1-1.5):(1-2).
6. The method for preparing a mercury ion imprinted membrane according to claim 2 or 3, characterized in that: The allylthiourea, EGDMA and Hg in the mercury salt 2+ The molar ratio is 4:20:
1.
7. The method for preparing a mercury ion imprinted membrane according to claim 2, characterized in that: The temperature of the water bath is 60-70°C and the time is 10min-24h.
8. The method for preparing a mercury ion imprinted membrane according to claim 2, characterized in that: The polymerization reaction process also includes a reflux stirring process.
9. A mercury ion imprinted membrane prepared by the method for preparing a mercury ion imprinted membrane according to any one of claims 1 to 8.
10. Use of the mercury ion imprinted membrane according to claim 9 in adsorbing mercury ions.