CN110339727A - A kind of preparation method and application of lead (II) ion trace composite membrane - Google Patents

Abstract

The invention discloses a preparation method and application of a divalent lead ion imprinted composite membrane, and belongs to the technical field of adsorption and separation functional polymer materials. The method of the present invention uses lead (II) ions as template ions, and the compound N-ethyl (1-benzene)-N-ethyl (2-diphenylphosphine)-2-acrylamide independently designed and synthesized as a function Monomer, ethylene glycol dimethacrylate as crosslinking agent, azobisisobutyronitrile as initiator, commercial film as base film, mixed solution of organic solvent and water as porogen, surface graft imprinting method , to imprint a thin polymer layer on the surface of the support membrane by thermal initiation. The preparation method of the lead (II) ion-imprinted composite membrane provided by the invention is easy to operate and low in economic cost, and the obtained lead (II) ion-imprinted composite membrane can adsorb and remove lead (II) ions in aqueous solution with high selectivity.

Description

A kind of preparation method and application of divalent lead ion imprinted composite film

technical field

The invention relates to a preparation method and application of a divalent lead ion imprinted composite membrane, and belongs to the technical field of adsorption and separation functional polymer materials.

Background technique

As an important development direction of molecular imprinting technology, metal ion imprinting technology has important academic and application value in the fields of environment, life and materials science. Ion imprinting technology uses ions as templates to form chelates through electrostatic interaction, coordination, etc., and monomers. After polymerization, the template ions are eluted with acidic reagents, etc., and finally a three-dimensional metal ion corresponding to the target metal ion is obtained. Imprinted material with hole structure.

Membrane separation technology refers to the technology that realizes selective separation of mixtures of molecules of different particle sizes at the molecular level when they pass through a semi-permeable membrane. According to the pore size, it can be divided into microfiltration membrane (MF), ultrafiltration membrane (UF), nanofiltration membrane Filter membrane (NF) and reverse osmosis membrane (RO), etc. Commonly used organic fluorine-containing commercial membranes mainly include polytetrafluoroethylene (PTFE) and polyvinylidene fluoride (PVDF). While the current commercial membranes cannot achieve the selective separation of individual substances, metal ion imprinting technology provides a feasible and effective solution for the separation of specific target ions from the mixture of their structural analogs.

Therefore, the combination of metal ion imprinting technology and membrane separation technology provides a practical technology for efficient and specific identification of metal ions. Nowadays, heavy metal pollution not only causes serious damage to the environment, but also poses a serious threat to human health. Among them, lead is a heavy metal pollutant with high toxicity, stable properties and difficult to be degraded. The accumulation of lead in the human body will damage the respiratory system, nervous system and hematopoietic system. Therefore, how to effectively solve the problem of lead pollution is an important task facing human beings.

Contents of the invention

The present invention provides a kind of preparation method of divalent lead ion imprinted composite membrane, it combines ion imprinted technology and membrane technology effectively, synthesizes lead (II) ion imprinted composite membrane, and its operation process is simple and easy, and condition is mild; The lead(II) ion-imprinted composite membrane prepared by the method can identify and adsorb divalent lead ions simply, quickly, and with high selectivity, and has high application value.

The method of the present invention specifically comprises the following steps:

(1) Preparation of pre-polymerization solution: Dissolve the template ion Pb(II) in the porogenic solvent at a ratio of 0.005-0.01g/L, and then add the functional monomer N-ethyl(1-benzene)-N-ethyl base (2-diphenylphosphine)-2-acrylamide, shake at room temperature for 2 to 3 hours, and finally add the cross-linking agent ethylene glycol dimethacrylate, the initiator azobisisobutyronitrile, and ultrasonic degassing Treat for 5-10 minutes to form a pre-polymerization solution.

(2) Preparation of lead(II) ion-imprinted composite film: place the base film in the pre-polymerization solution in the above step (1), soak it at room temperature for 3-60 minutes, then raise the temperature to 60-70°C for 24-48 hours, That is, the lead (II) ion imprinted composite membrane is prepared, and finally the template ions are removed by eluting with a mixed solution of methanol and acetic acid, and the lead (II) ion imprinted composite membrane with stereoscopic holes is obtained.

Preferably, the template ion, functional monomer and crosslinking agent molar ratio described in step (1) of the present invention is 1:(4～10):(20～50), and the mass molar ratio of initiator and functional monomer is 1: (10~15).

Preferably, the porogen of the present invention is a mixed solution of an organic solvent and water, and the volume ratio of the organic solvent to water is (1:3) to (3:1), wherein the organic solvent is methanol, ethanol, acetonitrile, N , one of N-dimethylformamide and isopropanol.

Preferably, the preparation method of functional monomer N-ethyl (1-benzene)-N-ethyl (2-diphenylphosphine)-2-acrylamide of the present invention is as follows:

(1) Weigh 10-20mmol compound N-hydroxyethylpyrrolidine into a reaction vessel, dissolve it with 50-70mL HCl, react to generate 1-(2-vinyl chloride)pyrrolidine, heat and reflux for 2-5h, and then use Cool in an ice-water bath, then add 5-10 mmol of acrylamide to the above reaction, continue to heat and stir for 5-10 hours, after the reaction is complete, cool to room temperature, add 10-30 ml of acryloyl chloride dropwise to the above-cooled mixture, Remove the ice-water bath after dripping, and react at room temperature for 12-24 hours;

(2) Post-treatment: After the reaction is completed, filter first, extract the filtrate with chloroform, wash with water to neutral pH, dry with anhydrous sodium sulfate, filter, and concentrate in vacuo, the residue is columnar with a mixed solution of petroleum ether and ethyl acetate. Chromatography showed that the volume ratio of petroleum ether and ethyl acetate was (20-30):(1-5), and a light yellow oily liquid was obtained by separation.

Preferably, the volume ratio of methanol and acetic acid in the mixed solution of methanol and acetic acid in step (2) of the present invention is (1-9):1.

Preferably, the base membrane in step (2) of the present invention is polytetrafluoroethylene microporous membrane (PTFE), polyvinylidene fluoride microporous membrane (PVDF), nylon-6 microporous membrane (Nylon-6) One of them, the base film is a commercially available product.

Another object of the present invention is to provide the lead (II) ion-imprinted composite membrane prepared by the method for absorbing and separating divalent lead ions in the solution.

The beneficial effects of the present invention are:

(1) The method of the present invention adopts the surface graft imprinting technology, and the compound N-ethyl(1-benzene)-N-ethyl(2-diphenylphosphine)-2-acrylamide independently designed and synthesized as the function Monomer, with a commercial microporous membrane as the supporting membrane, which overcomes the shortcomings of the current divalent lead ion adsorption materials, such as difficult preparation and complicated operation.

(2) The ion-imprinted composite membrane prepared by the method of the present invention exposes the recognition sites on the surface of the membrane, which can not only improve its specific recognition performance, but also increase its adsorption capacity for divalent lead ions.

Detailed ways

The present invention will be described in further detail below in conjunction with specific examples, but the protection scope of the present invention is not limited to the content described.

Example 1

A method for preparing a divalent lead ion imprinted composite membrane, specifically comprising the following steps:

(1) Preparation of functional monomer: Weigh 10mmol of the compound N-hydroxyethylpyrrolidine into a three-neck flask, dissolve it with 50mL of HCl, react to generate 1-(2-vinyl chloride)pyrrolidine, heat and reflux for 2h, and then use an ice-water bath Cool, then add 5mmol acrylamide to the above reaction, continue heating and stirring for 6h, after the reaction is complete, cool to room temperature, add 12ml acryloyl chloride dropwise to the above cooled mixture, remove the ice water bath after dropping, Reaction 12h. After the reaction is completed, first filter, the filtrate is extracted with chloroform, washed with water to neutral pH, dried over anhydrous sodium sulfate, filtered, and concentrated in vacuo, the residue is subjected to column chromatography with a mixed solution of petroleum ether and ethyl acetate, petroleum ether and The volume ratio of ethyl acetate was 20:1, and a pale yellow oily liquid was isolated.

(2) Add 0.1mmol Pb(NO ₃ ) ₂ to the porogen in the mixed solution of methanol and water with a volume ratio of 1:1. N-ethyl(2-diphenylphosphine)-2-acrylamide, shake at room temperature for 3h, make it mix evenly, then add 2mmol crosslinking agent ethylene glycol dimethacrylate and 15mg initiator azobisisobutyl Nitrile, shake well, and ultrasonic degassing treatment for 10 minutes to obtain the pre-polymerization solution.

(3) Place the polyvinylidene fluoride microporous filter membrane in the pre-polymerization solution obtained in step (1), soak at room temperature for 3 minutes, and then heat-initiate the reaction at 60°C for 24 hours.

(4) Elute the template ions with a mixed solution of methanol and acetic acid at a volume ratio of 9:1, and then wash with methanol to neutrality to obtain lead (II) with a shape and size matching that of the template ions and stereoscopic holes Ion imprinted composite membrane.

The 20.00 mg lead(II) ion-imprinted composite membrane prepared in this example was applied to a solution with a lead(II) concentration of 18 mg/mL for isothermal adsorption; the results showed that the adsorption capacity of the lead(II) ion-imprinted composite membrane was 990.49 μmol/g, the imprinting factor is 1.78.

Example 2

A method for preparing a divalent lead ion imprinted composite membrane, specifically comprising the following steps:

(1) Preparation of functional monomer: Weigh 17mmol of the compound N-hydroxyethylpyrrolidine into a three-neck flask, dissolve it with 72mL of HCl, react to generate 1-(2-vinyl chloride)pyrrolidine, heat and reflux for 3h, and then use an ice-water bath Cool, then add 10mmol acrylamide to the above reaction, continue to heat and stir for 7h, after the reaction is complete, cool to room temperature, add 13ml acryloyl chloride dropwise to the above cooled mixture, remove the ice water bath after dropping, Reaction 14h. After the reaction is completed, first filter, the filtrate is extracted with chloroform, washed with water to neutral pH, dried over anhydrous sodium sulfate, filtered, and concentrated in vacuo, the residue is subjected to column chromatography with a mixed solution of petroleum ether and ethyl acetate, petroleum ether and The volume ratio of ethyl acetate was 30:5, and a light yellow oily liquid was isolated.

(2) Add 0.1mmol Pb(NO ₃ ) ₂ to the porogen in the mixed solution of ethanol and water with a volume ratio of 1:1, and after it is completely dissolved, add 0.6mmol functional monomer N-ethyl(1-benzene)- N-ethyl(2-diphenylphosphine)-2-acrylamide, shake at room temperature for 3h, make it mix evenly, then add 3mmol crosslinking agent ethylene glycol dimethacrylate and 15mg initiator azobisisobutyl Nitrile, shake well, and ultrasonic degassing treatment for 10 minutes to obtain the pre-polymerization solution.

(3) Put the polytetrafluoroethylene microporous filter membrane (PTFE) in the pre-polymerization solution obtained in step (1), soak at room temperature for 10 minutes, and then thermally initiate the reaction at 60°C for 24 hours.

(4) Elute the template ions with a mixed solution of methanol and acetic acid at a volume ratio of 9:1, and then wash with methanol to neutrality to obtain lead (II) with a shape and size matching that of the template ions and stereoscopic holes Ion imprinted composite membrane.

The 20.00 mg lead (II) ion-imprinted composite membrane prepared in this example was applied to a solution with a lead (II) concentration of 18 mg/mL for isothermal adsorption; the results showed that the adsorption capacity of the lead (II) ion-imprinted composite membrane was 1010.31 The μmol/g imprinting factor was 2.01.

Example 3

A method for preparing a divalent lead ion imprinted composite membrane, specifically comprising the following steps:

(1) Preparation of functional monomer: Weigh 14mmol of the compound N-hydroxyethylpyrrolidine into a three-neck flask, dissolve it with 60mL of HCl, react to generate 1-(2-vinyl chloride)pyrrolidine, heat and reflux for 4h, and then use an ice-water bath After cooling, add 8 mmol of acrylamide to the above reaction, continue to heat and stir for 7 hours, after the reaction is complete, cool to room temperature, add 15 ml of acryloyl chloride dropwise to the above cooled mixture, remove the ice water bath after dropping, Reaction 18h. After the reaction is completed, first filter, the filtrate is extracted with chloroform, washed with water to neutral pH, dried over anhydrous sodium sulfate, filtered, and concentrated in vacuo, the residue is subjected to column chromatography with a mixed solution of petroleum ether and ethyl acetate, petroleum ether and The volume ratio of ethyl acetate was 25:4, and a pale yellow oily liquid was isolated.

(2) Add 0.1mmol Pb(NO ₃ ) ₂ to the porogen in the mixed solution of acetonitrile and water with a volume ratio of 1:1, wait until it is completely dissolved, then add 0.4mmol functional monomer N-ethyl (1-benzene) -N-Ethyl(2-diphenylphosphine)-2-acrylamide, shake at room temperature for 3h, make it evenly mixed, then add 4mmol crosslinking agent ethylene glycol dimethacrylate and 15mg initiator azobisiso Butyronitrile, shake well, and ultrasonic degassing treatment for 10 minutes to obtain the pre-polymerization solution.

(3) Place the nylon-6 microporous filter membrane (Nylon-6) in the pre-polymerization solution obtained in step (1), soak at room temperature for 20 minutes, and then heat-initiate the reaction at 60°C for 24 hours.

(4) Elute the template ions with a mixed solution of methanol and acetic acid at a volume ratio of 9:1, and then wash with methanol to neutrality to obtain lead (II) with a shape and size matching that of the template ions and stereoscopic holes Ion imprinted composite membrane.

The 20.00 mg lead(II) ion-imprinted composite membrane prepared in this example was applied to a solution with a lead(II) concentration of 18 mg/mL for isothermal adsorption. The results showed that the adsorption capacity of lead(II) ion-imprinted composite film was 957.43μmol/g and the imprinting factor was 1.60.

Example 4

A method for preparing a divalent lead ion imprinted composite membrane, specifically comprising the following steps:

(1) Preparation of functional monomer: Weigh 15mmol of the compound N-hydroxyethylpyrrolidine into a three-neck flask, dissolve it with 65mL of HCl, react to generate 1-(2-vinyl chloride)pyrrolidine, heat and reflux for 5h, and then use an ice-water bath Cool, then add 7mmol acrylamide to the above reaction, continue to heat and stir for 9h, after the reaction is complete, cool to room temperature, add 11ml of acryloyl chloride dropwise to the above cooled mixture, remove the ice water bath after dropping, Reaction 20h. After the reaction is completed, first filter, the filtrate is extracted with chloroform, washed with water to neutral pH, dried over anhydrous sodium sulfate, filtered, and concentrated in vacuo, the residue is subjected to column chromatography with a mixed solution of petroleum ether and ethyl acetate, petroleum ether and The volume ratio of ethyl acetate was 28:3, and a pale yellow oily liquid was isolated.

(2) Add 0.1mmol Pb(NO ₃ ) ₂ to the porogen in the mixed solution of N,N-dimethylformamide and water with a volume ratio of 1:1, wait until it is completely dissolved, then add 0.6mmol functional monomer N -Ethyl(1-benzene)-N-ethyl(2-diphenylphosphine)-2-acrylamide, shake at room temperature for 3h, make it evenly mixed, then add 5mmol crosslinking agent ethylene glycol dimethacrylate and 15 mg of initiator azobisisobutyronitrile, shake well, and ultrasonic degassing treatment for 10 minutes to obtain the pre-polymerization solution;

(3) Place the polyvinylidene fluoride microporous filter membrane in the pre-polymerization solution obtained in step (1), soak at room temperature for 30 minutes, and then heat-initiate the reaction at 60°C for 24 hours;

(4) Elute the template ions with a mixed solution of methanol and acetic acid at a volume ratio of 9:1, and then wash with methanol to neutrality to obtain lead (II) with a shape and size matching that of the template ions and stereoscopic holes Ion imprinted composite membrane.

The 20.00 mg lead(II) ion-imprinted composite membrane prepared in this example was applied to a solution with a lead(II) concentration of 18 mg/mL for isothermal adsorption. The results showed that the adsorption capacity of lead(II) ion-imprinted composite film was 960.76μmol/g and the imprinting factor was 1.58.

Example 5

A method for preparing a divalent lead ion imprinted composite membrane, specifically comprising the following steps:

(1) Preparation of functional monomer: Weigh 20mmol of the compound N-hydroxyethylpyrrolidine into a three-neck flask, dissolve it with 55mL of HCl, react to generate 1-(2-vinyl chloride)pyrrolidine, heat and reflux for 4h, and then use an ice-water bath Cool, then add 7mmol acrylamide to the above reaction, continue to heat and stir for 10h, after the reaction is complete, cool to room temperature, add 30ml of acryloyl chloride dropwise to the above cooled mixture, remove the ice water bath after dropping, Reaction 24h. After the reaction is completed, first filter, the filtrate is extracted with chloroform, washed with water to neutral pH, dried over anhydrous sodium sulfate, filtered, and concentrated in vacuo, the residue is subjected to column chromatography with a mixed solution of petroleum ether and ethyl acetate, petroleum ether and The volume ratio of ethyl acetate was 25:5, and a light yellow oily liquid was isolated.

(2) Add 0.1mmol of Pb(NO ₃ ) ₂ to the porogen in the mixed solution of isopropanol and water with a volume ratio of 1:1, and after it is completely dissolved, add 0.4mmol of the functional monomer N-ethyl (1-benzene )-N-ethyl(2-diphenylphosphorus)-2-acrylamide, shake at room temperature for 3h, make it mix evenly, then add 2mmol crosslinking agent ethylene glycol dimethacrylate and 15mg initiator azobis Isobutyronitrile, shake well, and ultrasonic degassing treatment for 10 minutes to obtain the pre-polymerization solution.

(3) Place the polyvinylidene fluoride microporous filter membrane in the pre-polymerization solution obtained in step 1, soak at room temperature for 60 minutes, and then heat-initiate the reaction at 60°C for 24 hours.

(4) Elute the template ions with a mixed solution of methanol and acetic acid at a volume ratio of 9:1, and then wash with methanol to neutrality to obtain lead (II) with a shape and size matching that of the template ions and stereoscopic holes Ion imprinted composite membrane.

The 20.00 mg lead(II) ion-imprinted composite membrane prepared in this example was applied to a solution with a lead(II) concentration of 18 mg/mL for isothermal adsorption. The results showed that the adsorption capacity of lead(II) ion-imprinted composite film was 1020.89μmol/g and the imprinting factor was 1.77.

The specific embodiments of the present invention have been described in detail above, but the present invention is not limited to the above embodiments, and various changes can be made without departing from the gist of the present invention within the scope of knowledge possessed by those of ordinary skill in the art .

Claims (7)

1. a kind of preparation method of lead (II) ion trace composite membrane, which is characterized in that specifically includes the following steps:

(1) template ion Pb (II): being dissolved in porogenic solvents by the preparation of pre-polymer solution in the ratio of 0.005~0.01g/L, Function monomer N- ethyl (1- benzene)-N- ethyl (2- diphenylphosphine) -2- acrylamide is added, vibrates 2~3h at room temperature, most After sequentially add crosslinking agent ethylene glycol dimethacrylate, initiator azodiisobutyronitrile, ultrasonic degassing handles 5~10min, Form pre-polymer solution；

(2) preparation of lead (II) ion blotting composite membrane: basement membrane is placed in the pre-polymer solution in above-mentioned steps (1), under room temperature 3~60min is impregnated, 24~48h of reaction at 60~70 DEG C is then heated to, obtains lead (II) ion blotting composite membrane, finally Template ion is removed with methanol and the elution of acetic acid mixed solution, it is compound to obtain lead (II) ion blotting with three-dimensional hole Film.

2. method according to claim 1, which is characterized in that template ion, function monomer and crosslinking agent described in step (1) Molar ratio is 1:(4~10): the quality molar ratio of (20~50), initiator and function monomer is 1:(10~15).

3. method according to claim 1, it is characterised in that: the pore-foaming agent is the mixed solution of organic solvent and water, is had Solvent and the volume ratio of water are (1:3)~(3:1), and wherein organic solvent is methanol, ethyl alcohol, acetonitrile, N, N- dimethyl formyl One of amine, isopropanol.

4. method according to claim 1, it is characterised in that: function monomer N- ethyl (1- benzene)-N- ethyl (2- diphenyl Phosphorus) -2- acrylamide the preparation method is as follows:

(1) 10~20mmol compound N-hydroxyethyl hydroxyethyl is weighed in reaction vessel, and is dissolved with 50~70mL HCl, instead 1- (2- vinyl chloride) pyrrolidines should be generated, 2~5h is heated to reflux, it is cooling with ice-water bath later, then by 5~10mmol acryloyl Amine is added in above-mentioned reaction, continues heating stirring and reacts 5~10h, after fully reacting, is cooled to room temperature, by 10~30ml propylene Acyl chlorides is added dropwise in above-mentioned mixed liquor after cooling, is dripped off and is removed ice-water bath, and room temperature reaction 12~for 24 hours；

(2) it post-processes: after completion of the reaction, first filtering, filtrate is extracted with chloroform, washing PH to neutrality, after anhydrous sodium sulfate is dry It filters, after vacuum concentration, residue carries out column chromatography, petroleum ether and ethyl acetate with the mixed solution of petroleum ether and ethyl acetate Volume ratio be (20~30): (1~5), isolated pale yellow oily liquid.

5. method according to claim 1, which is characterized in that methanol and vinegar in methanol and acetic acid mixed solution in step (2) The volume ratio of acid is (1~9): 1.

6. method according to claim 1, it is characterised in that: step (2) basement membrane is polytetrafluoroethylene (PTFE) miillpore filter (PTFE), one of polyvinylidene fluoride microporous filtering film (PVDF), nylon-6 miillpore filter (Nylon-6).

7. lead (II) the ion blotting composite membrane that claim 1 ~ 5 any one the method is prepared is molten for adsorbing separation Lead (II) ion in liquid.