阅读说明：本技术 一种PIM-1/Pebax复合渗透汽化膜及其制备方法和用途 (PIM-1/Pebax composite pervaporation membrane and preparation method and application thereof ) 是由 张国亮 李洋 于 2019-08-29 设计创作，主要内容包括：本发明公开了一种PIM-1/Pebax复合渗透汽化膜及其制备方法和用途。所述的制备方法为：将PIM-1溶于有机溶剂中,搅拌至均匀得到混合液A；将Pebax溶于乙醇和水的混合溶液中,搅拌至均匀,得到混合液B；所述的Pebax的加入量以所述的乙醇和水的混合溶液的体积计为0.01～0.5g/mL；取聚合物底膜浸渍于所述的混合液A和混合液B的混合溶液中,然后取出在室温下晾干,然后置于80℃下固化交联得到PIM-1/Pebax复合渗透汽化膜应用于渗透汽化过程分离醇水混合物,主要指正丁醇/水的分离。本发明采用了新型材料PIM-1混入Pebax中,两种疏水材料通过溶剂混合均匀,相转化制得复合膜,提高了醇水分离性能,制备方法简单,价格低廉,有较好的应用前景。(The invention discloses a PIM-1/Pebax composite pervaporation membrane and a preparation method and application thereof. The preparation method comprises the following steps: PIM-1 is dissolved in an organic solvent and stirred to be uniform to obtain a mixed solution A; dissolving Pebax in a mixed solution of ethanol and water, and stirring uniformly to obtain a mixed solution B; the adding amount of the Pebax is 0.01-0.5 g/mL calculated by the volume of the mixed solution of the ethanol and the water; and (2) soaking the polymer basement membrane in the mixed solution of the mixed solution A and the mixed solution B, taking out the polymer basement membrane, airing the polymer basement membrane at room temperature, and curing and crosslinking the polymer basement membrane at 80 ℃ to obtain the PIM-1/Pebax composite pervaporation membrane which is applied to the separation of alcohol-water mixtures in the pervaporation process, wherein the separation of the alcohol-water mixtures mainly refers to the separation of n-butanol/water. The invention adopts the novel material PIM-1 to be mixed into the Pebax, the two hydrophobic materials are uniformly mixed through the solvent, and the composite membrane is prepared through phase conversion, so that the alcohol-water separation performance is improved, the preparation method is simple, the price is low, and the application prospect is good.)

1. A PIM-1/Pebax composite pervaporation membrane, characterized in that: the PIM-1/Pebax composite pervaporation membrane is prepared according to the following method:

(1) PIM-1 is dissolved in an organic solvent and stirred to be uniform to obtain a mixed solution A; the addition amount of the PIM-1 is 0.01-0.5 g/mL based on the volume of the organic solvent;

(2) Dissolving Pebax in a mixed solution of ethanol and water, and stirring uniformly to obtain a mixed solution B; the adding amount of the Pebax is 0.01-0.5 g/mL calculated by the volume of the mixed solution of the ethanol and the water;

(3) soaking a polymer basement membrane in the mixed solution of the mixed solution A and the mixed solution B, taking out the polymer basement membrane, airing the polymer basement membrane at room temperature, and curing and crosslinking the polymer basement membrane at 80 ℃ to obtain a PIM-1/Pebax composite pervaporation membrane; the bottom membrane is a flat membrane or a hollow fiber membrane; the addition amount of the mixed solution A is calculated by the mass of the PIM-1, the addition amount of the mixed solution B is calculated by the mass of the Pebax, and the mass ratio of the PIM-1 to the Pebax is 0.02-0.3: 1.

2. the PIM-1/Pebax composite pervaporation membrane according to claim 1, wherein: in the step (1), the organic solvent is chloroform, dichloromethane or tetrahydrofuran.

3. the PIM-1/Pebax composite pervaporation membrane according to claim 1, wherein: in the step (2), the volume ratio of the ethanol to the water is 10-3: 1.

4. The PIM-1/Pebax composite pervaporation membrane according to claim 1, wherein: in the step (3), the basement membrane is made of polyvinylidene fluoride, polypropylene, polyacrylonitrile, polyethylene, polyvinyl chloride, polysulfone, polyether sulfone or polyimide.

5. the PIM-1/Pebax composite pervaporation membrane according to claim 1, wherein: in the step (3), the basement membrane is a microfiltration membrane or an ultrafiltration membrane.

6. The PIM-1/Pebax composite pervaporation membrane according to claim 1, wherein: in the step (3), the dipping time is 1-20 min.

7. The PIM-1/Pebax composite pervaporation membrane according to claim 1, wherein: in the step (3), the curing and crosslinking time is 12 hours.

8. The PIM-1/Pebax composite pervaporation membrane as defined in claim 1 applied to the separation of alcohol-water mixture in pervaporation process.

9. The use of claim 8, wherein: the alcohol-water mixture is a mixture of n-butanol and water.

Technical Field

The invention relates to a PIM-1/Pebax composite pervaporation membrane and a preparation method and application thereof, belonging to the technical field of functional membrane preparation and separation application.

Background

Pervaporation is a membrane separation technique that combines membrane permeation and evaporation for the selective separation of a mixture of liquid molecules. Mass transfer processes are generally described by solution diffusion mechanisms and facilitated transport mechanisms, and although the phase change from liquid to vapor occurs in pervaporation, only the latent heat of vaporization is required. Compared with the traditional separation technology such as distillation and the like, the pervaporation has the advantages of high separation coefficient, low energy consumption, simple operation, no introduction of a third component, no limitation of vapor-liquid balance and the like, and has wide development prospect and market potential in the aspects of energy chemical industry, food, beverage, medicine and health and industrial separation. Meanwhile, the pervaporation membrane can prepare a permeable or alcohol-permeable separation membrane on the surface of the membrane by utilizing the characteristics of the high-molecular polymer, and the pervaporation separation technology has the characteristics of high efficiency, energy conservation, easy control and the like, and the conditions enable the pervaporation membrane separation technology to be correspondingly applied in the field of solving the problems of separation, concentration and the like of ethanol, isopropanol and butanol.

Currently, pervaporation membrane materials are mainly classified into three types: polymers, inorganic materials and composite materials. Because of the low cost, easy processing, good mechanical stability and adjustable transportation property of the polymer, the polymer is the first pervaporation membrane material which is most widely applied. However, polymer membranes have poor anti-fouling properties, low chemical and thermal stability, and in particular there is an inherent limitation between permeability and selectivity. In contrast, inorganic membranes have unique advantages such as higher chemical and thermal stability, higher solvent swell resistance, and more favorable mechanical properties, and many times, inorganic membranes work well at high temperatures with different raw material compositions and concentrations. However, inorganic films also have significant inherent limitations, such as poor film forming properties, high brittleness, and thus, are more difficult to make into ideal defect-free films. In this case, a composite film obtained by combining a polymer and an inorganic material has been vigorously searched in recent years because the composite film combines the excellent properties of a polymer and an inorganic material. Composite membranes have 4 typical characteristics: multiple interactions, multi-scale structures, multi-phases and multiple functionalities. Polymer matrix and filler materials such as hydrogen bonds, pi-pi interactions, van der waals forces, covalent or ionic bonds between different interactions may be introduced into the composite film. The composite method is the most effective pervaporation membrane preparation method which is used most at present. The compounding method is to compound an ultra-thin functional layer with a nano-scale aperture on the surface of the ultrafiltration or microfiltration basement membrane. The method has the advantages that different materials can be used as the base film and the composite layer, the functional layer has ideal separation performance, and the base film has good supporting effect.

At present, the method for separating the n-butanol-water system mainly comprises the modes of extractive distillation, salt-dissolving extraction, solvent extraction, pervaporation and the like. The pervaporation is a high-efficiency low-concentration alcohol recovery mode with low energy consumption and no introduction of other impurities, and the existing separation membrane is generally low in separation coefficient and low in concentration of the recovered alcohol.

disclosure of Invention

compared with the prior art, the invention aims to prepare the PIM-1/Pebax composite pervaporation membrane, and introduces two hydrophobic materials PIM-1 and Pebax to construct a cross-linked polymer network for separating an alcohol-water mixture in the pervaporation process, mainly referring to the separation of n-butanol/water. The technical scheme of the invention is as follows:

A PIM-1/Pebax composite pervaporation membrane is prepared by the following steps:

(1) PIM-1 is dissolved in an organic solvent and stirred to be uniform to obtain a mixed solution A; the addition amount of the PIM-1 is 0.01-0.5 g/mL based on the volume of the organic solvent;

(2) Dissolving Pebax in a mixed solution of ethanol and water, and stirring uniformly to obtain a mixed solution B; the adding amount of the Pebax is 0.01-0.5 g/mL calculated by the volume of the mixed solution of the ethanol and the water;

(3) Soaking a polymer basement membrane in the mixed solution of the mixed solution A and the mixed solution B, taking out the polymer basement membrane, airing the polymer basement membrane at room temperature, and curing and crosslinking the polymer basement membrane at 80 ℃ to obtain a PIM-1/Pebax composite pervaporation membrane; the bottom membrane is a flat membrane or a hollow fiber membrane; the addition amount of the mixed solution A is calculated by the mass of the PIM-1, the addition amount of the mixed solution B is calculated by the mass of the Pebax, and the mass ratio of the PIM-1 to the Pebax is 0.02-0.3: 1.

Further, in the step (1), the PIM-1 can be synthesized according to the following method:

mixing 5,5 ', 6,6 ' -tetrahydroxy-3, 3,3 ', 3 ' -tetramethyl-1, 1 ' -spirobiindane (TTSBI), tetrafluoroterephthalonitrile (DCTB), and K₂CO₃Placing the mixture in DMAc and toluene solution, refluxing for 40min at 160 ℃, pouring the obtained viscous fluid into methanol, and stirring, wherein noodle-shaped solids are generated; filtering and washing with acetone, and drying in an oven to obtain solid PIM-1; the mass ratio of TTSBI to TFTN is 3: 1-2; the TTSBI and K₂CO₃The mass ratio is 1: 1-2; the adding amount of the DMAc is 4-6ml/g based on the mass of the TTSBI; the volume ratio of DMAc to toluene is 1:1-2: 1; the volume ratio of the methanol to the DMAc is 1: 1.5-2; the volume ratio of the acetone to the methanol is 1: 1-1.5; the oven temperature is 100-130 ℃.

Further, in the step (1), the organic solvent may be chloroform, dichloromethane or tetrahydrofuran.

Further, in the step (2), the volume ratio of the ethanol to the water is 10-3: 1.

Further, in the step (3), the material of the bottom membrane is polyvinylidene fluoride, polypropylene, polyacrylonitrile, polyethylene, polyvinyl chloride, polysulfone, polyethersulfone or polyimide.

Further, in the step (3), the basement membrane is a microfiltration membrane or an ultrafiltration membrane.

Further, in the step (3), the dipping time is 1-20 min.

Further, in the step (3), the curing and crosslinking time is preferably 12 hours.

Compared with the prior art, the invention has the advantages that: the invention adopts the novel material PIM-1 to be mixed into the Pebax, the two hydrophobic materials are uniformly mixed through the solvent, and the composite membrane is prepared through phase conversion, so that the alcohol-water separation performance is improved, the preparation method is simple, the price is low, and the application prospect is good.

The invention is further illustrated by the following examples.

Drawings

FIG. 1 is a surface SEM image of a PIM-1/Pebax composite pervaporation membrane.

Detailed Description

the present invention will be described in detail below with reference to specific examples, but the present invention is not limited to the following examples, and various modifications and implementations are included within the technical scope of the present invention without departing from the content and scope of the present invention.

The preparation method of the PIM-1 comprises the following steps: 12g of 5,5 ', 6,6 ' -tetrahydroxy-3, 3,3 ', 3 ' -tetramethyl-1, 1 ' -spirobiindane (TTSBI), 4g of tetrafluoroterephthalonitrile (DCTB), 12g K₂CO₃Placing the mixture in 60mL of DMAc and 60mL of toluene solution, refluxing for 40min at 160 ℃, pouring the obtained viscous fluid into 100mL of methanol, and stirring to obtain noodle-shaped solid; and (3) carrying out suction filtration and washing by using 120mL of acetone, and then drying in an oven at 120 ℃ to obtain the solid PIM-1.

Example 1

Weighing 0.1g of PIM-1, dissolving in 5mL of chloroform, stirring for 1h, and performing ultrasonic treatment for 30min to uniformly disperse the mixture to obtain a mixed solution A; 0.5g of Pebax was weighed out and dissolved in 25mL of an aqueous solution of ethanol, the volume ratio of ethanol to water being 7: 3, obtaining a mixed solution B. 0.0382g of ethyl orthosilicate and 0.002g of dibutyl tin dilaurate are added into the mixed solution B, then 2mL of the mixed solution A and 18mL of the mixed solution B are uniformly mixed, and ultrasonic treatment is carried out for 1h to obtain a PIM-1/Pebax mixed solution;

And (2) taking a polyvinylidene fluoride ultrafiltration membrane with the pore diameter of 0.22 mu m and the diameter of 50mm as a bottom membrane, soaking in the obtained PIM-1/Pebax mixed solution for 1 minute, removing redundant solution on the surface of the bottom membrane, standing the coated membrane at room temperature for 12 hours, standing at 80 ℃ for 12 hours, and accelerating crosslinking to obtain the PIM-1/Pebax composite membrane.

carrying out pervaporation test on the prepared PIM-1/Pebax composite membrane on 1 wt% of n-butanol aqueous solution, wherein the operation temperature is 60 ℃, the operation time is 1 hour, and the actual membrane area of the test is 7.065cm²The flux of the membrane is 1.86kg/m under the negative pressure of 0.1MPa²h, of n-butanolThe separation factor was 32.5.

Example 2

Weighing 0.1g of PIM-1, dissolving in 5mL of chloroform, stirring for 1h, and performing ultrasonic treatment for 30min to uniformly disperse the mixture to obtain a mixed solution A; 0.5g of Pebax was weighed out and dissolved in 25mL of an aqueous solution of ethanol, the volume ratio of ethanol to water being 7: 3, obtaining a mixed solution B. Adding 0.0382g of ethyl orthosilicate and 0.002g of dibutyl tin dilaurate into the mixed solution B, then uniformly mixing 2mL of mixed solution A with 18mL of mixed solution B, and carrying out ultrasonic treatment for 1h to obtain a PIM-1/Pebax mixed solution;

And (2) taking a polyvinylidene fluoride ultrafiltration membrane with the pore diameter of 0.22 mu m and the diameter of 50mm as a bottom membrane, soaking in the obtained PIM-1/Pebax mixed solution for 1 minute, removing redundant solution on the surface of the bottom membrane, standing the coated membrane at room temperature for 12 hours, standing at 80 ℃ for 12 hours, and accelerating crosslinking to obtain the PIM-1/Pebax composite membrane.

Carrying out pervaporation test on the prepared PIM-1/Pebax composite membrane on 1 wt% of n-butanol aqueous solution, wherein the operation temperature is 60 ℃, the operation time is 1 hour, and the actual membrane area of the test is 7.065cm²The flux of the membrane is 2.3kg/m under the negative pressure of 0.1MPa²H, separation coefficient for n-butanol of 28.1.

Example 3

Weighing 0.1g of PIM-1, dissolving in 5mL of chloroform, stirring for 1h, and performing ultrasonic treatment for 30min to uniformly disperse the mixture to obtain a mixed solution A; 0.5g of Pebax was weighed out and dissolved in 25mL of an aqueous solution of ethanol, the volume ratio of ethanol to water being 7: 3, obtaining a mixed solution B. Adding 0.0382g of ethyl orthosilicate and 0.002g of dibutyl tin dilaurate into the mixed solution B, uniformly mixing 2mL of mixed solution A with 18mL of mixed solution B, and performing ultrasonic treatment for 1h to obtain a PIM-1/Pebax mixed solution

And (2) dipping a polyvinylidene fluoride hollow fiber ultrafiltration membrane serving as a bottom membrane into the PIM-1/Pebax mixed solution for 1 minute, removing redundant solution on the surface of the bottom membrane, standing the coated membrane at room temperature for 12 hours, standing at 80 ℃ for 12 hours, and accelerating crosslinking to obtain the PIM-1/Pebax composite membrane.

Carrying out pervaporation test on the prepared PIM-1/Pebax composite membrane on 1 wt% n-butanol aqueous solution, wherein the operation temperature is 60 ℃, the operation time is 1 hour, and the flux of the membrane is 2.15kg/m under the negative pressure of 0.1MPa²h, separation coefficient for n-butanol is 34.2.

Comparative example 1

0.5g of Pebax was weighed out and dissolved in 25mL of an aqueous solution of ethanol, the volume ratio of ethanol to water being 7: 3, obtaining a mixed solution A. 0.0382g of tetraethoxysilane and 0.002g of dibutyl tin dilaurate are added into the solution A and ultrasonic treatment is carried out for 1 hour to obtain a Pebax mixed solution

And (2) dipping the polyvinylidene fluoride ultrafiltration membrane with the pore diameter of 0.22 mu m and the diameter of 50mm serving as a bottom membrane into the obtained Pebax mixed solution for 1 minute, removing redundant solution on the surface of the bottom membrane, standing the coated membrane at room temperature for 12 hours, standing at 80 ℃ for 12 hours, and accelerating crosslinking to obtain the Pebax composite membrane.

carrying out pervaporation test on 1 wt% of n-butanol aqueous solution by using the prepared Pebax composite membrane, wherein the operation temperature is 60 ℃, the operation time is 1 hour, the actual membrane area of the test is 7.065cm2, and the flux of the membrane is 15.3kg/m under the condition that the negative pressure is 0.1MPa²H, separation coefficient for n-butanol of 3.2.