阅读说明：本技术 一种气相聚合制备聚酰胺膜的方法及聚酰胺膜与应用 (Method for preparing polyamide membrane through gas-phase polymerization, polyamide membrane and application ) 是由 李万斌 陈世政 苏鹏程 于 2021-07-27 设计创作，主要内容包括：本发明属于膜技术领域,具体提供了一种气相聚合制备聚酰胺膜的方法。所述方法首先将二胺类单体,加入到溶剂中搅拌分散,将所得溶液均匀涂覆在基底表面,干燥后获得含有二胺类单体的基底；将酰氯化合物放入容器底部,将制备的含有二胺类单体的基底放入容器内,酰氯化合物与含有二胺类单体的基底不发生直接接触,密封容器后,进行气相聚合反应,反应结束后干燥得到聚酰胺膜。通过改进聚酰胺膜的合成方法,避免反应过程中有机溶剂的使用,使反应过程更加绿色高效。本发明方法具有广泛的通用性,可以用于多种材质与构型的基底,为其工业化应用奠定基础。(The invention belongs to the technical field of films, and particularly provides a method for preparing a polyamide film by gas-phase polymerization. Adding diamine monomers into a solvent, stirring and dispersing, uniformly coating the obtained solution on the surface of a substrate, and drying to obtain the substrate containing the diamine monomers; placing an acyl chloride compound at the bottom of a container, placing the prepared substrate containing the diamine monomer into the container, sealing the container, carrying out gas-phase polymerization reaction, and drying after the reaction to obtain the polyamide membrane. By improving the synthesis method of the polyamide membrane, the use of organic solvents in the reaction process is avoided, so that the reaction process is more green and efficient. The method has wide universality, can be used for substrates of various materials and configurations, and lays a foundation for industrial application of the substrates.)

1. A method for preparing a polyamide membrane by gas phase polymerization, characterized by comprising the steps of:

(1) preparation of a substrate containing diamine monomers:

adding diamine monomers into a solvent, stirring and dispersing, uniformly coating the obtained solution on the surface of a substrate, and drying to obtain the substrate containing the diamine monomers;

(2) preparation of polyamide membranes by gas phase polymerization:

placing an acyl chloride compound into the bottom of a container, and placing the substrate containing the diamine monomer prepared in the step (1) above the acyl chloride compound, wherein the acyl chloride compound is not in direct contact with the substrate containing the diamine monomer; after the vessel was sealed, a gas phase polymerization reaction was carried out, and after the reaction was completed, the polyamide film was dried to obtain a polyamide film.

2. The method of claim 1, wherein: the temperature of the gas-phase polymerization reaction in the step (2) is 40-150 ℃, and the time of the gas-phase polymerization reaction is 5-72 hours.

3. The method of claim 1, wherein: the acyl chloride compound in the step (2) is trimesoyl chloride, paraphthaloyl chloride, malonyl chloride, 1, 3-benzene disulfonyl chloride, 1, 4-cyclohexane diacyl chloride or cyclohexane triacyl chloride.

4. The method of claim 1, wherein:

the dosage of the acyl chloride compound in the step (2) is satisfied, and each dosage is 2.5-225 cm²0.1 to 2g of an acid chloride compound is used as the substrate.

5. The method of claim 1, wherein: in the step (1), the diamine monomer is at least one of piperazine, p-phenylenediamine, m-phenylenediamine, o-phenylenediamine, ethylenediamine, m-xylylenediamine, diaminotoluene and xylylenediamine.

6. The method of claim 1, wherein: in the step (1), the solvent is at least one of water, methanol, ethanol, glycol and glycerol.

7. The method of claim 1, wherein: in the step (1), the mass concentration of the solution is 1-10 mg/mL.

8. The method of claim 1, wherein: in the step (1), the substrate is made of polysulfone, polyethersulfone, polypropylene, polyethylene, polytetrafluoroethylene, polyvinylidene fluoride, polyacrylonitrile, polyetherimide, cellulose, alumina, titanium dioxide, copper, iron or zinc;

in the step (1), the configuration of the substrate is a flat plate type, a tubular type, a net type or a hollow fiber type; the drying temperature in the step (1) is 20-150 ℃; the drying temperature in the step (2) is 20-100 ℃.

9. A polyamide membrane produced by the method according to any one of claims 1 to 8.

10. Use of a polyamide membrane according to claim 9 in nanofiltration of organic solvents.

Technical Field

The invention belongs to the technical field of membranes, and mainly provides a method for preparing a polyamide membrane by gas-phase polymerization, the polyamide membrane and application.

Background

With the rapid growth of population and the aggravation of environmental pollution, the problem of water resource shortage is widely concerned by people. The traditional water treatment technology comprises adsorption, microbial degradation, flocculation precipitation and the like, and the problems of low separation efficiency, high cost and the like exist, so that the application and the popularization are limited. The membrane separation technology has the advantages of low energy consumption, environmental friendliness and simplicity in operation, and is widely applied to drinking water quality control, wastewater treatment and industrial production. Among the membrane separation technologies, nanofiltration and reverse osmosis can produce high removal efficiency for organic small molecules and inorganic salts, and thus become the most common technical means for seawater desalination and small molecule removal.

As the most commonly used nanofiltration and reverse osmosis membranes, polyamide membranes are mainly prepared by liquid phase interfacial polymerization of amine monomers in aqueous solutions and acid chloride monomers in organic solutions. The traditional liquid phase interfacial polymerization method needs to use a large amount of organic solvent, thereby not only increasing the production cost of the polyamide membrane, but also causing great harm to the environment. Therefore, the method has important significance and good application prospect by exploring and developing a simple, feasible, economic and environment-friendly new method for synthesizing the polyamide membrane.

Disclosure of Invention

In order to overcome the above-mentioned drawbacks and disadvantages of the prior art, it is a primary object of the present invention to provide a method for preparing a polyamide film by gas phase polymerization.

The invention also aims to provide a gas-phase polymerization prepared polyamide membrane prepared by the method.

The invention further aims to provide the application of the polyamide membrane prepared by gas phase polymerization in organic solvent nanofiltration.

The purpose of the invention is realized by the following scheme:

a method for preparing a polyamide membrane by gas phase polymerization, comprising the steps of:

(1) preparation of a substrate containing diamine monomers:

adding diamine monomers into a solvent, stirring and dispersing, uniformly coating the obtained solution on the surface of a substrate, and drying to obtain the substrate containing the diamine monomers;

(2) preparation of polyamide membranes by gas phase polymerization:

placing an acyl chloride compound into the bottom of a container, and placing the substrate containing the diamine monomer prepared in the step (1) above the acyl chloride compound, wherein the acyl chloride compound is not in direct contact with the substrate containing the diamine monomer; after the vessel was sealed, a gas phase polymerization reaction was carried out, and after the reaction was completed, the polyamide film was dried to obtain a polyamide film.

In the step (1), the diamine monomer is at least one of piperazine, p-phenylenediamine, m-phenylenediamine, o-phenylenediamine, ethylenediamine, m-xylylenediamine, diaminotoluene and xylylenediamine.

In the step (1), the solvent is at least one of water, methanol, ethanol, glycol and glycerol.

In the step (1), the mass concentration of the solution is 1-10 mg/mL, preferably 2-5 mg/mL.

In the step (1), the configuration of the substrate is flat plate type, tubular type, net type or hollow fiber type.

In the step (1), the substrate is made of polysulfone, polyethersulfone, polypropylene, polyethylene, polytetrafluoroethylene, polyvinylidene fluoride, polyacrylonitrile, polyetherimide, cellulose, alumina, titanium dioxide, copper, iron or zinc.

The drying temperature in the step (1) is preferably 20-150 ℃.

In the step (2), the acyl chloride compound is trimesoyl chloride, terephthaloyl chloride, malonyl chloride, 1, 3-benzene disulfonyl chloride, 1, 4-cyclohexane diacyl chloride or cyclohexane triacyl chloride.

The dosage of the acyl chloride compound in the step (2) is satisfied, and each dosage is 2.5-225 cm²0.1 to 2g of an acid chloride compound is used as the substrate; more preferably, 0.2 to 1g of the acid chloride compound is used.

The temperature of the gas-phase polymerization reaction in the step (2) is 40-150 ℃, and the time of the gas-phase polymerization reaction is 5-72 hours.

The drying temperature in the step (2) is 20-100 ℃.

A polyamide membrane prepared by the above gas phase polymerization method.

The polyamide membrane is applied to nanofiltration of an organic solvent.

The invention provides a method for preparing a polyamide membrane by gas-phase polymerization through gas-phase deposition reaction of acyl chloride monomers based on the characteristic that the acyl chloride monomers are easy to gasify in the polymerization reaction. The chemical gas phase polymerization process can deposit continuous polyamide layer on the surface of the substrate without complex pretreatment of the substrate, and the method has good universality and is suitable for various types of polyamide films. In addition, the obtained polyamide membrane shows excellent stability and nanofiltration performance in both water and organic solvent systems.

Compared with the prior art, the invention has the following advantages and beneficial effects:

(1) the polyamide membrane is prepared by a gas-phase polymerization method, the synthesis method of the polyamide membrane is improved, and the use of an organic solvent in the reaction process is avoided. In addition, the method also has the characteristics of simple process and easy amplification.

(2) The polyamide membrane prepared by the gas phase polymerization method exhibits excellent separation performance.

(3) The method has wide universality, can be used for substrates of various materials and configurations, and lays a foundation for industrial application of the substrates.

Drawings

FIG. 1 is a FTIR spectrum of a polyamide film prepared in example 1 of the present invention;

FIG. 2 is an SEM photograph of a polyamide membrane produced in example 1 of the present invention after desalting;

FIG. 3 is an O1S XPS plot of a polyamide film prepared in example 1 of the present invention;

FIG. 4 is a C1S XPS plot of a polyamide membrane prepared according to example 1 of the present invention, with the inset being an SEM image of the polyamide membrane after desalting.

FIG. 5 shows a polyamide thin film composite membrane pair of Na at different feed pressures₂SO₄Desalting performance of the solution.

Detailed Description

The present invention will be described in further detail with reference to examples and drawings, but the embodiments of the present invention are not limited thereto.

The reagents used in the examples are commercially available without specific reference.

Example 1

The substrate is polysulfone flat sheet membrane (225 cm)²) Monomer A is piperazine (PIP) and monomer B is trimesoyl chloride (TMC).

The preparation method comprises the following steps:

(1) preparation of a substrate containing diamine monomers:

20mg of diamine monomer piperazine (PIP) is added into 20mL of deionized water and stirred for dispersion, and a piperazine (PIP) solution is obtained after sufficient dissolution. The piperazine (PIP) solution was uniformly coated on the surface of the substrate and dried at 80 c to obtain a piperazine (PIP) -containing substrate.

(2) Preparation of polyamide membranes by gas phase polymerization:

0.2g of trimesoyl chloride (TMC) was placed in the bottom of the vessel, and the substrate containing piperazine (PIP) prepared in step (1) was placed in the vessel without direct contact between piperazine (PIP) and trimesoyl chloride (TMC). The reaction kettle is sealed and heated at 50 ℃ to gasify trimesoyl chloride (TMC) and carry out gas-phase polymerization for 20 hours. And after the reaction is finished and the system is cooled, taking out the synthesized film, washing the film with deionized water, and drying the film at the temperature of 100 ℃ to obtain the polyamide film.

As shown by the FTIR spectrum in FIG. 1, the deposited TFC film has an IR spectrum with O-C-N at 1733cm-¹The new characteristic peak at (a) confirms successful polymerization of the polyamide layer. Fig. 2 is an SEM image of a polyamide film having a relatively smooth surface, as compared to an original substrate having a rough surface, due to a relatively flat polyamide layer formed after deposition. The XPS spectra in FIGS. 4 and 3 show that a Schotten-Baumann reaction occurs between piperazine (PIP) and trimesoyl chloride (TMC). FIG. 5 is a graph showing the desalting performance of a polyamide membrane under Na₂SO₄In the nanofiltration desalination of the solution, the membrane flux and the retention rate are respectively 6.8Lm^-2h^-1bar^-1And 96.2% and exhibits good stability at various feed pressures.

Example 2

The substrate is polysulfone flat sheet membrane (225 cm)²) The monomer A is m-phenylenediamine (MPD), and the monomer B is trimesoyl chloride (TMC).

The preparation method comprises the following steps:

(1) preparation of a substrate containing diamine monomers:

50mg of diamine monomer m-phenylenediamine (MPD) was added to 20mL of methanol and dispersed with stirring to obtain a solution of m-phenylenediamine (MPD). The metaphenylene diamine (MPD) solution is uniformly coated on the surface of the substrate and dried at 60 ℃ to obtain the substrate containing metaphenylene diamine (MPD).

(2) Preparation of polyamide membranes by gas phase polymerization:

0.5g of trimesoyl chloride (TMC) was placed in the bottom of a vessel, and the substrate containing m-phenylenediamine (MPD) prepared in the step (1) was placed in the vessel without direct contact between the m-phenylenediamine (MPD) and the trimesoyl chloride (TMC). The reaction kettle is sealed and heated at 50 ℃ to gasify trimesoyl chloride (TMC) and carry out gas-phase polymerization for 12 h. And after the reaction is finished and the system is cooled, taking out the synthesized film, washing the film by using deionized water, and drying the film at the temperature of 80 ℃ to obtain the polyamide film.

Example 3

The substrate is a polyether sulfone flat membrane (225 cm)²) The monomer A is p-phenylenediamine (PPD) and the monomer B is isophthaloyl dichloride (IPC).

The preparation method comprises the following steps:

(1) preparation of a substrate containing diamine monomers:

100mg of diamine monomer p-phenylenediamine (PPD) was added to 25mL of ethanol and dispersed by stirring, and the solution was sufficiently dissolved to obtain a p-phenylenediamine (PPD) solution. The surface of the substrate was uniformly coated with a solution of p-phenylenediamine (PPD) and dried at 100 ℃ to obtain a substrate containing p-phenylenediamine (PPD).

(2) Preparation of polyamide membranes by gas phase polymerization:

0.6g of isophthaloyl chloride (IPC) was placed in the bottom of the vessel, and the substrate containing p-phenylenediamine (PPD) prepared in step (1) was placed in the vessel without direct contact between p-phenylenediamine (PPD) and isophthaloyl chloride (IPC). The autoclave was sealed and heated at 150 ℃ to vaporize isophthaloyl dichloride (IPC), and the gas phase polymerization was carried out for 72 hours. And after the reaction is finished and the system is cooled, taking out the synthesized film, washing the film with deionized water, and drying the film at the temperature of 100 ℃ to obtain the polyamide film.

Example 4

The substrate is a polyacrylonitrile flat membrane (225 cm)²) The monomer A is o-phenylenediamine (OPD) and the monomer B is isophthaloyl dichloride (IPC).

The preparation method comprises the following steps:

(1) preparation of a substrate containing diamine monomers:

40mg of diamine monomer o-phenylenediamine (OPD) was added to 20mL of ethylene glycol and dispersed with stirring to obtain an o-phenylenediamine (OPD) solution after sufficient dissolution. The surface of the substrate was uniformly coated with a solution of p-phenylenediamine (PPD) and dried at 40 ℃ to obtain a substrate containing o-phenylenediamine (OPD).

(2) Preparation of polyamide membranes by gas phase polymerization:

0.3g of isophthaloyl chloride (IPC) was placed in the bottom of the vessel, and the substrate containing o-phenylenediamine (OPD) prepared in step (1) was placed in the vessel without direct contact between o-phenylenediamine (OPD) and isophthaloyl chloride (IPC). The reaction vessel was sealed and heated at 100 ℃ to vaporize isophthaloyl dichloride (IPC), and a gas phase polymerization was carried out for 5 hours. And after the reaction is finished and the system is cooled, taking out the synthesized film, washing the film with deionized water, and drying the film at 50 ℃ to obtain the polyamide film.

Example 5

The substrate is polyvinylidene fluoride hollow fiber membrane (2.5 cm)²) Monomer A is Diaminotoluene (DAT) and monomer B is 1, 4-cyclohexanedicarbonyl Chloride (CDD).

The preparation method comprises the following steps:

(1) preparation of a substrate containing diamine monomers:

100mg of Diaminotoluene (DAT), a diamine monomer, was added to 40mL of ethanol and dispersed with stirring to obtain a Diaminotoluene (DAT) solution. The substrate surface was uniformly coated with a Diaminotoluene (DAT) solution and dried at 120 ℃ to obtain a substrate containing Diaminotoluene (DAT).

(2) Preparation of polyamide membranes by gas phase polymerization:

0.3g of 1, 4-cyclohexanedicarboxylic acid Chloride (CDD) was placed in the bottom of the vessel and the substrate containing Diaminotoluene (DAT) prepared in step (1) was placed in the vessel without direct contact of the Diaminotoluene (DAT) with the 1, 4-cyclohexanedicarboxylic acid Chloride (CDD). The reaction kettle is sealed and heated at 85 ℃ to gasify the 1, 4-cyclohexanedicarboxylic acid Chloride (CDD) and carry out gas-phase polymerization for 36 h. And after the reaction is finished and the system is cooled, taking out the synthesized film, washing the film by using deionized water, and drying the film at the temperature of 60 ℃ to obtain the polyamide film.

Example 6

The substrate is a polyethylene flat membrane (225 cm)²) The monomer A is m-xylylenediamine (MXDA), and the monomer B is terephthaloyl chloride (TPC).

The preparation method comprises the following steps:

(1) preparation of a substrate containing diamine monomers:

80mg of diamine monomer m-xylylenediamine (MXDA) was added to 20mL of methanol and dispersed with stirring to obtain a solution of m-xylylenediamine (MXDA) after sufficient dissolution. A solution of m-xylylenediamine (MXDA) was uniformly coated on the surface of the substrate, and dried at 60 ℃ to obtain a substrate containing m-xylylenediamine (MXDA).

(2) Preparation of polyamide membranes by gas phase polymerization:

placing 1g of terephthaloyl chloride (TPC) into the bottom of a container, and placing the substrate containing m-xylylenediamine (MXDA) prepared in step (1) into the container without direct contact between m-xylylenediamine (MXDA) and terephthaloyl chloride (TPC). The reaction kettle is sealed and heated at 100 ℃ to gasify the terephthaloyl chloride (TPC) and carry out gas-phase polymerization for 16 h. And after the reaction is finished and the system is cooled, taking out the synthesized film, washing the film by using deionized water, and drying the film at the temperature of 80 ℃ to obtain the polyamide film.

The FTIR spectra of the polyamide films obtained in examples 2 to 6 were similar to those of example 1.

Comparative example (preparation by conventional interfacial polymerization)

The substrate is a polysulfone ultrafiltration membrane (225 cm)²) The water phase monomer is piperazine (PIP), and the organic phase monomer is trimesoyl chloride (TMC).

The preparation method comprises the following steps:

(1) immersing the polysulfone ultrafiltration membrane into 0.35% PIP aqueous solution for 2min, taking out the PIP-loaded polysulfone membrane, placing on a glass inclined plate, allowing the excessive solution to flow out, and sucking off the residual water on the surface with filter paper.

(2) Clamping the membrane in the step (1) in a polytetrafluoroethylene circular plate, and pouring a TMC n-hexane solution with the mass fraction of 1% into the surface of the ultrafiltration membrane for reaction for 20 s. And (3) washing the membrane with a normal hexane solution for 3 times, putting the membrane into a 50 ℃ oven for 3min, taking out the membrane, and putting the membrane into deionized water for storage.

As can be seen from the comparative example, the polyamide thin film composite membrane synthesized by the conventional interfacial polymerization method (IP) uses toxic organic solvents, which not only harms human health, but also causes environmental pollution. The polyamide membrane prepared by the conventional liquid phase interfacial polymerization method exhibited a poor nanofiltration performance, Na, as compared to the polyamide prepared by the gas phase polymerization method in example 1₂SO₄The rejection was 95.7% as compared to Na from example 1₂SO₄The retention rate is 96.2%, which proves the superiority of preparing the polyamide membrane by a gas phase polymerization method.

The above embodiments are preferred embodiments of the present invention, but the present invention is not limited to the above embodiments, and any other changes, modifications, substitutions, combinations, and simplifications which do not depart from the spirit and principle of the present invention should be construed as equivalents thereof, and all such changes, modifications, substitutions, combinations, and simplifications are intended to be included in the scope of the present invention.