CN108187504B - APTS modified silicon dioxide filled PIM-1 composite membrane, preparation method thereof and method for separating and purifying n-butanol - Google Patents

APTS modified silicon dioxide filled PIM-1 composite membrane, preparation method thereof and method for separating and purifying n-butanol Download PDF

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CN108187504B
CN108187504B CN201711459171.0A CN201711459171A CN108187504B CN 108187504 B CN108187504 B CN 108187504B CN 201711459171 A CN201711459171 A CN 201711459171A CN 108187504 B CN108187504 B CN 108187504B
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composite membrane
pim
butanol
membrane
solution
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CN108187504A (en
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兰永强
彭平
肖旺钏
苏志忠
李奇勇
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Sanming University
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D67/00—Processes specially adapted for manufacturing semi-permeable membranes for separation processes or apparatus
    • B01D67/0079—Manufacture of membranes comprising organic and inorganic components
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
    • B01D61/36—Pervaporation; Membrane distillation; Liquid permeation
    • B01D61/362—Pervaporation
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D69/00—Semi-permeable membranes for separation processes or apparatus characterised by their form, structure or properties; Manufacturing processes specially adapted therefor
    • B01D69/02—Semi-permeable membranes for separation processes or apparatus characterised by their form, structure or properties; Manufacturing processes specially adapted therefor characterised by their properties
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D69/00—Semi-permeable membranes for separation processes or apparatus characterised by their form, structure or properties; Manufacturing processes specially adapted therefor
    • B01D69/10—Supported membranes; Membrane supports
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D69/00—Semi-permeable membranes for separation processes or apparatus characterised by their form, structure or properties; Manufacturing processes specially adapted therefor
    • B01D69/12—Composite membranes; Ultra-thin membranes
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C29/00—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring
    • C07C29/74—Separation; Purification; Use of additives, e.g. for stabilisation
    • C07C29/76—Separation; Purification; Use of additives, e.g. for stabilisation by physical treatment
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2323/00—Details relating to membrane preparation
    • B01D2323/04—Hydrophobization
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2325/00—Details relating to properties of membranes
    • B01D2325/38—Hydrophobic membranes

Abstract

The invention provides an APTS modified silicon dioxide filled PIM-1 composite membrane, a preparation method thereof and a method for separating and purifying n-butanol, and relates to the technical field of pervaporation membranes. The preparation method of the composite membrane comprises the following steps: the method is characterized in that 3-Aminopropyltriethoxysilane (APTS) is used for modifying nano gas-phase silica, modified silica particles are used as a filler and added into a soluble intrinsic microporous polymer (PIM-1) matrix, a Cellulose Acetate (CA) microfiltration membrane is used as a supporting layer, and a flat plate pervaporation composite membrane is prepared, can effectively separate and purify the n-butanol solution, is strong in hydrophobicity and good in pervaporation performance, and has high n-butanol separation capacity while ensuring high permeation flux.

Description

APTS modified silicon dioxide filled PIM-1 composite membrane, preparation method thereof and method for separating and purifying n-butanol
Technical Field
The invention relates to the technical field of pervaporation membranes, and particularly relates to an APTS modified silica-filled PIM-1 composite membrane, a preparation method thereof, and a method for separating and purifying n-butanol.
Background
With the increasing energy crisis and the increasing environmental pollution, the development of clean energy is attracting attention. The n-butanol is an important chemical raw material and is expected to become a new generation of biofuel, and the preparation of the n-butanol by adopting the renewable biomass fermentation is receiving more and more attention. The n-butyl alcohol can be added into the gasoline in a high proportion, so that the combustion efficiency of the gasoline is greatly improved, and meanwhile, the combustion of the n-butyl alcohol only can produce carbon dioxide and water, so that the environment cannot be polluted. The butanol as the fermentation product has toxicity inhibiting effect on the fermentation strains, so that the efficiency of preparing the biological butanol by adopting the fermentation method is not high at present, and the butanol is not widely applied. At present, the traditional distillation method is adopted to separate butanol, the separation efficiency of the distillation method is low, a large amount of fuel energy consumption exists, and meanwhile, the fuel combustion causes extra pollution, and the industrial production is difficult to realize.
Compared with a distillation method, the pervaporation membrane separation technology has the advantages of good separation selectivity, low energy consumption and no pollution. The pervaporation and fermentation method is combined, so that the separation efficiency of the n-butanol can be obviously improved, and the environment can not be polluted. Patent CN103877874A discloses a method for preparing a polydimethylsiloxane-carbon nanotube composite membrane, a composite membrane thereof, and a method for separating and purifying butanol, wherein carbon nanotubes are added into polydimethylsiloxane, so that although permeation flux and separation factors in the butanol separation process are improved to a certain extent, the improvement of separation efficiency is limited, and the cost of the carbon nanotubes is high.
Disclosure of Invention
The invention aims to provide a preparation method of an APTS modified silicon dioxide filled PIM-1 composite membrane, which is simple, easy to operate and suitable for industrial production.
The invention also aims to provide an APTS modified silica filled PIM-1 composite membrane, which is obtained by adding modified silica particles into a PIM-1 matrix, ensures high permeation flux and has high butanol separation capacity.
The third purpose of the invention is to provide a method for separating and purifying n-butanol, which adopts the composite membrane to separate and purify the n-butanol solution and has excellent effect.
The technical problem to be solved by the invention is realized by adopting the following technical scheme.
The invention provides a preparation method of an APTS modified silicon dioxide filled PIM-1 composite membrane, which comprises the following steps:
s1, PIM-1 preparation: mixing 5,5',6,6' -tetrahydroxy-3, 3,3',3' -tetramethyl-1, 1' -spiro-indole, tetrafluoroterephthalonitrile, a catalyst and a first solvent, heating and stirring for 30-60 min at 140-165 ℃ under the condition of introducing inert gas to obtain a crude product, dissolving the crude product with a second solvent, stirring for 5-15 min, filtering, washing and drying to obtain PIM-1, wherein the catalyst comprises K2CO3；
S2, preparation of modified silica: dispersing nano fumed silica and 3-Aminopropyltriethoxysilane (APTS) in a third solvent, magnetically stirring for 50-80 min, and then carrying out ultrasonic treatment for 20-40 min to obtain a modified silica solution;
s3, pouring the modified silicon dioxide solution into a PIM-1 solution with the mass fraction of 8-12%, and mixing to obtain a membrane casting solution;
and S4, taking the cellulose acetate microfiltration membrane as a supporting layer, and forming an active cortex on the surface of the cellulose acetate microfiltration membrane by the membrane casting solution to obtain the composite membrane.
The invention provides an APTS modified silicon dioxide filled PIM-1 composite membrane, which is prepared according to the preparation method.
The invention provides a method for separating and purifying n-butanol, which uses the composite membrane to separate and purify a n-butanol solution.
The APTS modified silicon dioxide filled PIM-1 composite membrane, the preparation method thereof and the method for separating and purifying n-butanol have the beneficial effects that:
PIM-1 is a soluble intrinsically microporous polymer that is capable of achieving micropores by its own rigidity and non-planar structure of molecules, which has superior permselectivity and separation efficiency compared to other membrane separation materials. APTS (3-Aminopropyltriethoxysilane ) is adopted to modify silicon dioxide, the surface hydrophobicity of the silicon dioxide is improved, when the modified silicon dioxide is taken as a filler and introduced into a PIM matrix, the hydrophobicity of the composite membrane can be improved, the pervaporation performance of the composite membrane is obviously improved, and the composite membrane has high n-butanol separation capacity while ensuring high permeation flux.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present invention and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained according to the drawings without inventive efforts.
FIG. 1 is an SEM photograph of a PIM-1 composite membrane according to example 2 of the present invention;
FIG. 2 is an infrared spectrum of unmodified silica and APTS modified silica;
FIG. 3 is a graph showing the relationship between the contact angle of the PIM-1 composite membrane and the amount of modified silica added;
FIG. 4 is a graph showing the relationship between the swelling degree of the PIM-1 composite membrane and the addition amount of modified silica;
FIG. 5 is a graph showing the effect of the addition of modified silica on the pervaporation performance of a PIM-1 composite membrane;
FIG. 6 is a graph of the effect of operating temperature on separation performance;
FIG. 7 is a graph showing the effect of feed solution concentration on separation performance.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. The examples, in which specific conditions are not specified, were conducted under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products available commercially.
The APTS-modified silica-filled PIM-1 composite membrane, the preparation method thereof, and the method for separating and purifying n-butanol according to the embodiment of the present invention will be specifically described below.
The preparation method of the APTS modified silicon dioxide filled PIM-1 composite membrane provided by the embodiment of the invention comprises the following steps:
s1, PIM-1 preparation: mixing 5,5',6,6' -tetrahydroxy-3, 3,3',3' -tetramethyl-1, 1' -spiro-indole, tetrafluoroterephthalonitrile, a catalyst and a first solvent, heating and stirring for 30-60 min at 140-165 ℃ under the condition of introducing inert gas to obtain a crude product, dissolving the crude product with a second solvent, stirring for 5-15 min, filtering, washing and drying to obtain PIM-1, wherein the catalyst comprises K2CO3。
S2, preparation of modified silica: dispersing the nano fumed silica and the 3-aminopropyltriethoxysilane in a third solvent, magnetically stirring for 50-80 min, and then carrying out ultrasonic treatment for 20-40 min to obtain a modified silica solution.
S3, pouring the modified silicon dioxide solution into the PIM-1 solution with the mass fraction of 8-12%, and mixing to obtain the membrane casting solution.
And S4, taking the CA microfiltration membrane as a supporting layer, and forming an active cortex on the surface of the CA microfiltration membrane by the membrane casting solution to obtain the composite membrane.
Further, in a preferred embodiment of the present invention, in step S1, the mass ratio of 5,5',6,6' -tetrahydroxy-3, 3,3',3' -tetramethyl-1, 1' -spirobiindole, tetrafluoroterephthalonitrile, and catalyst is 2 to 2.5: 1.5-2: 1. the PIM-1 matrix prepared according to the proportion has better gas permeability and selectivity, good stability, solubility and easy film formation. Compared with common membrane materials such as PVDF and the like, the method has higher gas permeation advantage and can effectively separate n-butanol molecules.
Further, the catalyst is K with the mass ratio of 1: 0.1-0.32CO3And Nd2O3In the presence of catalyst K2CO3Middle addingAnd a small amount of rare earth oxide is added, so that the synthesis of the polymer can be effectively promoted, the molecular weight is higher, and the microporous polymer with higher performance is obtained.
Further, in a preferred embodiment of the present invention, in the composite film, the mass fraction of the modified silica is 2 to 8%. More preferably, the mass fraction of the modified silica is 4 to 8%. The modified silicon dioxide has a hydrophobic structure, the hydrophobic property prevents the coagulation of capillary tubes, and the n-butyl alcohol adsorption performance of the filling modified composite membrane is good. With the increase of the content of the modified silicon dioxide, the permeation flux of the PIM-1 composite membrane is obviously increased, and the separation factor of the membrane is obviously increased. However, if the content of the modified silica is too high, the separation factor is lowered.
Further, in a preferred embodiment of the present invention, the first solvent is toluene and N, N-dimethylacetamide in a volume ratio of 1: 2-3. The solvent is more favorable for the polycondensation reaction of the polymer. Furthermore, in the preparation process of PIM-1, under the condition of introducing inert gas, the temperature is raised and the stirring reaction is carried out by stages, which is more favorable for improving the performance of the PIM-1 matrix, for example, the PIM-1 matrix is heated and stirred for 10min at 140 ℃, and then heated and stirred for 40min at 160 ℃ to obtain a crude product.
Further, in a preferred embodiment of the present invention, the second solvent is a mixture of chloroform and methanol. The crude product was dissolved in a chloroform/methanol mixture, filtered to obtain a precipitate, and then the solvent and salts were washed off from the precipitated product with deionized water to purify the product. Preferably, the washed product is dried at 100 ℃ for 12h to give PIM-1.
Further, in a preferred embodiment of the present invention, the third solvent is selected from one or more of chloroform, dichloromethane, and tetrachloromethane.
Further, in step S2, the mass ratio of the silica nanoparticles to the APTS is 1 to 1.2:1, and further the mass ratio is 1: 1. According to the proportion, the silicon dioxide nano particles can be effectively modified, and the modified silicon dioxide nano particles with better hydrophobic property are obtained.
Further, in step S3, a certain amount of PIM-1 is weighed, and an appropriate amount of solvent is added to obtain a PIM-1 solution with a mass fraction of 8-12%. The solvent in the PIM-1 solution is preferably one or more of chloroform, dichloromethane and tetrachloromethane. The solvent can well dissolve PIM-1, and is convenient for the preparation of a subsequent composite membrane and the dispersion of modified silicon dioxide particles.
Further, in a preferred embodiment of the present invention, the CA microfiltration membrane is immersed in the pretreatment solution in advance for 2-3 hours, and the pretreatment solution is water or an alkaline aqueous solution of dopamine. The base membrane, namely the CA microfiltration membrane, is soaked in the treatment solution in advance, so that liquid molecules can occupy membrane holes of the base membrane and the space on the back of the base membrane, and the casting solution cannot permeate into the holes. Further, when the treatment solution is an alkaline aqueous solution of dopamine, the dopamine can undergo oxidation-autopolymerization under the condition of the alkaline aqueous solution to form a polydopamine functional surface layer which is strongly adhered to the surface of the substrate. The polydopamine functional surface layer has excellent surface activity and adhesion capacity, and on one hand, the active skin layer can be tightly combined on the supporting layer to enhance the product performance. On the other hand, amino and hydroxyl on the polydopamine functional surface layer can be chemically bonded with silicon hydroxyl on the surface of the modified silicon dioxide to form secondary functionalization, so that the vaporization permeability of the composite membrane is effectively improved. Furthermore, in the alkaline aqueous solution, the concentration of the dopamine is 0.7-1 g/L, the pH value is 8-8.5, and a proper polydopamine functional surface layer can be formed.
Further, in a preferred embodiment of the present invention, the composite film is further subjected to a post-treatment step: and drying the composite membrane at 70-90 ℃ for 2-4 days.
The APTS modified silicon dioxide filled PIM-1 composite membrane provided by the embodiment of the invention is prepared according to the preparation method.
The method for separating and purifying the n-butanol provided by the embodiment of the invention uses the composite membrane to separate and purify the n-butanol solution. The feed liquid concentration and the operation temperature of the n-butyl alcohol solution play a key role in the pervaporation performance of the PIM composite membrane, and preferably, when the composite membrane is used for separating and purifying the n-butyl alcohol solution, the operation temperature is 20-50 ℃, and the feed liquid concentration is 5-25%.
Example 1
The APTS-modified silica-filled PIM-1 composite membrane provided in this embodiment is prepared according to the following method:
(1) pretreatment of the support layer: the CA microfiltration membrane was placed in deionized water for 2h before use.
(2) Preparation of PIM-1: 8.3g K2CO36.8g of 5,5',6,6' -tetrahydroxy-3, 3,3',3' -tetramethyl-1, 1' -spirobiindole, 4g of tetrafluoroterephthalonitrile, 15mL of toluene and 30mL of N, N-dimethylacetamide were added to a 500mL three-necked flask. The mixture was heated and stirred at 155 ℃ and then stirred with nitrogen. The crude product was collected after 40 min. Dissolving the crude product with chloroform/methanol mixture, stirring for 10min, filtering to obtain precipitate, and washing off solvent and salt in the precipitate with deionized water. The product was then placed in a vacuum oven at 100 ℃ for 12h to give PIM-1 final product.
(3) Preparation of PIM-1 solution: accurately weighing a certain amount of PIM-1 by using an analytical balance, placing the PIM-1 in a dry and clean beaker I, and adding a proper amount of chloroform solvent to obtain a PIM-1 solution with the mass fraction of 10%. The mixture is placed on a magnetic stirrer and stirred for 12 hours.
(4) Preparing modified silicon dioxide nano particles: firstly, the nano fumed silica is placed in a vacuum drying oven at 120 ℃, and is taken out after drying moisture for 48 hours. Taking a certain mass of silicon dioxide nano particles, then sequentially adding APTS and chloroform as a solvent, placing the mixed solution on a magnetic stirrer, stirring for 1h, and then ultrasonically oscillating for 30min to obtain a modified silicon dioxide solution.
(5) Preparing a casting solution: and pouring a proper amount of modified silicon dioxide solution into the beaker I according to the addition of 2 percent of modified silicon dioxide, magnetically stirring for 1h, standing and defoaming for 30min, and obtaining a uniform mixed solution, namely the membrane casting solution.
(6) Preparing a composite membrane: and (3) taking the CA microfiltration membrane out of water while preparing the casting solution, flatly paving the CA microfiltration membrane on a glass plate, wiping water on the upper surface by using filter paper, fixing the CA microfiltration membrane on the glass plate by using a transparent adhesive tape, and placing the glass plate on a film scraping machine. Pouring the prepared casting solution on a CA micro-filtration membrane, and quickly and uniformly spreading the casting solution on the surface of a base membrane to form an active cortex layer with uniform thickness.
(7) And (3) post-treatment: and (3) putting the substrate and the prepared composite membrane into a drying oven at 80 ℃ for 3 days for high-temperature treatment, taking out after the solvent is completely volatilized, and cleaning by using deionized water to obtain the composite membrane, namely the final product.
The PIM-1 composite membrane prepared in the embodiment has the permeation flux of 528 g.m.measured by measuring the pervaporation performance in a 5% butanol aqueous solution at 40 DEG C-2h-1The separation factor was 13.1.
Example 2
The difference between the APTS-modified silica-filled PIM-1 composite membrane provided in this example and example 1 is that the amount of modified silica added is 4%.
The PIM-1 composite membrane prepared in the example has the permeation flux of 508 g.m.measured by measuring the pervaporation performance in 5% butanol aqueous solution at 40 DEG C-2h-1The separation factor was 15.0.
Example 3
The difference between the APTS-modified silica-filled PIM-1 composite membrane provided in this example and example 1 is that the amount of modified silica added is 6%.
The PIM-1 composite membrane prepared in the example has the permeation flux of 553 g.m.measured by the pervaporation performance of 5% butanol aqueous solution at 40 DEG C-2h-1The separation factor was 13.5.
Example 4
The difference between the APTS-modified silica-filled PIM-1 composite membrane provided in this example and example 1 is that the addition amount of the modified silica is 8%.
The PIM-1 composite membrane prepared in the embodiment has the permeation flux of 752 g.m.measured by the pervaporation performance of a 5% butanol aqueous solution at 40 DEG C-2h-1The separation factor was 11.8.
Example 5
The difference between the APTS modified silica-filled PIM-1 composite membrane provided in this example and example 2 is that the pretreatment of the support layer: before use, the CA microfiltration membrane is placed in an alkaline aqueous solution with the dopamine concentration of 1g/L for reaction for 2 hours.
The PIM-1 composite membrane prepared in the example has the permeation flux of 552 g.m.measured by the pervaporation performance of a 5% butanol aqueous solution at 40 DEG C-2h-1The separation factor was 15.9.
Comparative example 1
This comparative example provides a PIM-1 membrane, which was prepared by a method different from that of example 1 in that the modified silica was added in an amount of 0 in the PIM-1 substrate.
The PIM-1 membrane prepared in the comparative example has a permeation flux of 548 g.m when measured for pervaporation at 40 ℃ in a 5% butanol aqueous solution-2h-1The separation factor was 6.4.
Comparative example 2
The present comparative example provides a PDMS composite film, prepared according to the following method:
(1) pretreatment of the support layer: the CA microfiltration membrane was placed in deionized water for 2h before use.
(2) Preparation of PDMS solution: accurately weighing a certain amount of PDMS by using an analytical balance, placing the PDMS in a dry and clean beaker I, and adding a proper amount of solvent n-hexane to obtain a PDMS solution with the mass fraction of 10%. The mixture is placed on a magnetic stirrer and stirred for 12 hours.
(3) Preparing modified silicon dioxide nano particles: firstly, the nano fumed silica is placed in a vacuum drying oven at 120 ℃, and is taken out after drying moisture for 48 hours. Taking a certain mass of silicon dioxide nano particles, then sequentially adding APTS and chloroform as a solvent, placing the mixed solution on a magnetic stirrer, stirring for 1h, and then ultrasonically oscillating for 30min to obtain a modified silicon dioxide solution.
(4) Preparing a casting solution: and pouring a proper amount of modified silicon dioxide solution into the beaker I according to the addition of 4 percent of modified silicon dioxide, magnetically stirring for 1h, standing and defoaming for 30min, and obtaining a uniform mixed solution, namely the membrane casting solution.
(5) Preparing a composite membrane: and (3) taking the CA microfiltration membrane out of water while preparing the casting solution, flatly paving the CA microfiltration membrane on a glass plate, wiping water on the upper surface by using filter paper, fixing the CA microfiltration membrane on the glass plate by using a transparent adhesive tape, and placing the glass plate on a film scraping machine. Pouring the prepared casting solution on a CA micro-filtration membrane, and quickly and uniformly spreading the casting solution on the surface of a base membrane to form an active cortex layer with uniform thickness.
(6) And (3) post-treatment: and (3) putting the substrate and the prepared composite membrane into a drying oven at 80 ℃ for 3 days for high-temperature treatment, taking out after the solvent is completely volatilized, and cleaning by using deionized water to obtain the composite membrane, namely the final product.
The PDMS composite membrane prepared by the comparative example is used for measuring the pervaporation performance in a 5% butanol aqueous solution at 40 ℃, and the permeation flux is 356 g.m-2h-1The separation factor was 7.6.
As shown in fig. 1, which is an SEM image of the PIM-1 composite membrane provided in example 3 of the present invention, it can be seen from fig. 1 that a defect-free dense composite membrane was successfully prepared. In the PIM-1 matrix, the modified silicon dioxide is shown to have no agglomeration phenomenon, and the addition of the modified silicon dioxide does not influence the arrangement of PIM-1 molecular chains.
The infrared spectrum of the nano-silica is shown in fig. 2. In FIG. 2, 1 is an infrared spectrum of an unmodified silica particle, and 2 is an infrared spectrum of a modified silica particle. The modified silicon dioxide is at 2930cm-1(CH2Stretch) and 1470cm-1(CH2Bend) shows a characteristic absorption peak of the silane coupling agent, and APTS at 1720cm-1Characteristic peak of (C ═ O stretching). Hydroxyl absorption peak of unmodified silica 3450cm-1Significantly reduced because of the condensation reaction of the hydroxyl groups on the surface thereof with the silane coupling agent. In addition, the characteristic peaks of the modified silica were changed from the position and intensity of the unmodified silica, indicating that a chemical reaction occurred between APTS and the nanosilica.
As shown in FIG. 3, the hydrophobicity of the PIM-1 composite membrane was measured by using a water contact angle. As the content of the modified silica increased, the contact angle of the membrane surface increased, indicating that the addition of the modified silica increased the hydrophobicity of the composite membrane. The value of the water contact angle at the surface of the modified silica film is greater than that of the unmodified film. The value of the water contact angle increases with increasing modified silica content in the film. The reason for this is that APTS changes the hydrophilic surface of the nano silica particles to be hydrophobic. Therefore, when the filler is introduced into the PIM-1 matrix, the surface hydrophobicity of the modified membrane is effectively improved.
As shown in FIG. 4, the influence of the modified silica on the anti-swelling performance of the PIM-1 composite membrane was investigated by a swelling experiment. As can be seen from fig. 4, as the content of the modified silica nanoparticles decreases, the degree of swelling of the PIM-1 composite membrane gradually decreases, confirming that the solvent adsorption capacity of the composite membrane gradually decreases. The main reason is that the addition of the modified silicon dioxide nano particles reduces the gaps in the composite film, thereby improving the anti-swelling capacity of the composite film. It can be seen from the figure that the swelling resistance of the PIM-1 composite membrane is higher than that of the pure PIM-1 membrane.
As shown in fig. 5, the pervaporation performance of the PIM-1 composite membrane was tested in a 5 wt% butanol solution at 40 ℃. In fig. 5, 1 is a variation trend line of the separation factor, and 2 is a variation trend line of the permeation flux. With the increase of the content of the modified silicon dioxide, the permeation flux of the PIM-1 composite membrane is obviously increased, and the separation factor of the membrane is obviously increased. The increase in the separation factor is due to the addition of modified nanosilica. The increase in hydrophobicity of the composite membrane is a key factor for the increase in separation factor. The intrinsic reason for this is that the modified silica has a hydrophobic structure, and the hydrophobicity of the modified silica prevents the capillary condensation effect. Therefore, the butanol adsorption performance of the composite membrane filled with the modified silicon dioxide is good, and the diffusion selectivity plays a key role in a solution diffusion mechanism. Butanol molecules can pass through the composite membrane due to their flexible structure. Chemical potential gradients are the driving force for water molecules to pass through the composite membrane. Thus, the low friction and low resistance of the hydrophobic transport pathway to butanol molecules is responsible for the high permeation flux of butanol. In general, a larger volume of butanol molecules results in lower permeability, but the permeability of butanol molecules in the composite membrane is higher due to the hydrophobic permeation pathway. Whereas water molecules have to spiral in the composite membrane and then pass through the membrane. The increase in hydrophobicity results in a PIM-1 composite membrane having higher selectivity. When the content of the modified silica is more than 4 wt%, a decrease in separation factor of the composite membrane occurs due to various degrees of agglomeration caused by excessive modified silica. Figure 5 shows the effect of modified silica content on the separation factor. First, the separation factor increases with increasing modified silica content and then decreases. The proper amount of modified silica particles disrupts the regular arrangement of segments and increases the free volume, however, more modified silica particles can lead to defects in the composite membrane. The effect is best when the amount of the modified silica added is 4 wt% by seeking a balance between the above two mechanisms.
As shown in fig. 6, the operating temperature plays a key role in influencing the pervaporation performance of PIM-1 composite membranes. Therefore, it is important to discuss the influence of the permeability on the vaporization performance. The influence of the operation temperature on the separation performance of the PIM-1 composite membrane was studied in a 5 wt% aqueous n-butanol solution. In fig. 6, 1 is a variation trend line of the separation factor, and 2 is a variation trend line of the permeation flux. The permeate flux increased significantly with increasing operating temperature. However, as the operating temperature increases, the butanol flux decreases while the water flux increases. The temperature increases the chemical potential of the upstream portion of butanol and water, resulting in an increase in the difference in the upstream and downstream chemical potentials. And the increase in temperature increases the activity of the PIM-1 molecule, thereby increasing the free volume. As the operating temperature increases, the diffusion rates of both butanol and water molecules increase. However, the butanol molecules are larger than water molecules, and the water diffusion rate is increased more than the butanol diffusion rate, thereby improving the selectivity.
As shown in FIG. 7, the effect of PIM-1 feed solution concentration on the separation performance of the composite membrane was investigated in a 5% butanol aqueous solution at 40 ℃. From fig. 7, 1 is a variation trend line of the separation factor, and 2 is a variation trend line of the permeation flux. As butanol concentration increased, the total flux increased significantly and the separation factor decreased gradually. The diffusion of water and butanol molecules is affected by plasticization and partial pressure. In one aspect, the driving force for butanol diffusion increases as the partial pressure of butanol increases. As the concentration of butanol increases, more and more butanol molecules are dissolved in the PIM-1 composite membrane, thereby increasing the swelling degree of the composite membrane, thereby increasing the free volume, resulting in an increase in the flux of both water and butanol. Excessive butanol concentration can cause excessive swelling of the composite membrane, resulting in increased hydrophilicity of the permeation pathway, manifested as increased flux of water, while butanol flux increases and then decreases with increasing feed solution concentration, resulting in a decrease in the separation factor.
The embodiments described above are some, but not all embodiments of the invention. The detailed description of the embodiments of the present invention is not intended to limit the scope of the invention as claimed, but is merely representative of selected embodiments of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Claims (8)

1. A preparation method of an APTS modified silicon dioxide filled PIM-1 composite membrane is characterized by comprising the following steps:
s1, PIM-1 preparation: mixing 5,5',6,6' -tetrahydroxy-3, 3,3',3' -tetramethyl-1, 1' -spiro-indole, tetrafluoroterephthalonitrile, a catalyst and a first solvent, heating and stirring for 30-60 min at 140-165 ℃ under the condition of introducing inert gas to obtain a crude product, dissolving the crude product with a second solvent, stirring for 5-15 min, filtering, washing and drying to obtain PIM-1, wherein the catalyst is K with the mass ratio of 1: 0.1-0.32CO3And Nd2O3；
S2, preparation of modified silica: dispersing nano fumed silica and 3-aminopropyltriethoxysilane in a third solvent, magnetically stirring for 50-80 min, and then carrying out ultrasonic treatment for 20-40 min to obtain a modified silica solution;
s3, pouring the modified silicon dioxide solution into a PIM-1 solution with the mass fraction of 8-12%, and mixing to obtain a membrane casting solution;
s4, taking the cellulose acetate microfiltration membrane as a supporting layer, and forming an active cortex on the surface of the cellulose acetate microfiltration membrane by the membrane casting solution to obtain a composite membrane; the cellulose acetate microfiltration membrane is soaked in a pretreatment solution in advance for 2-3 hours, and the pretreatment solution is an alkaline aqueous solution of dopamine;
in the composite membrane, the mass fraction of the modified silicon dioxide is 2-8%.
2. The production method according to claim 1, wherein in step S1, the mass ratio of the 5,5',6,6' -tetrahydroxy-3, 3,3',3' -tetramethyl-1, 1' -spirobiindole, the tetrafluoroterephthalonitrile, and the catalyst is 2 to 2.5: 1.5-2: 1.
3. the preparation method according to claim 1, wherein the first solvent is toluene and N, N-dimethylacetamide in a volume ratio of 1: 2-3.
4. The method according to claim 1, wherein the second solvent is a mixture of chloroform and methanol.
5. The method according to claim 1, wherein the third solvent is selected from one or more of chloroform, dichloromethane, and tetrachloromethane.
6. The method of claim 1, wherein the composite membrane is further subjected to a post-treatment step of: and drying the composite membrane at 70-90 ℃ for 2-4 days.
7. An APTS modified silica-filled PIM-1 composite membrane, characterized by being prepared by the preparation method of any one of claims 1 to 6.
8. A method for separating and purifying n-butanol, characterized in that the APTS-modified silica-filled PIM-1 composite membrane according to claim 7 is used for separating and purifying the n-butanol solution.
CN201711459171.0A 2017-12-28 2017-12-28 APTS modified silicon dioxide filled PIM-1 composite membrane, preparation method thereof and method for separating and purifying n-butanol Active CN108187504B (en)

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* Cited by examiner, † Cited by third party
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Non-Patent Citations (3)

* Cited by examiner, † Cited by third party
Title
High-flux PIM-1/PVDF thin film composite membranes for 1-butanol/water pervaporation;Lei Gao.et. al;《Journal of Membrane Science》;20170207;第207-214页 *
Linear High Molecular Weight Ladder Polymer via Fast Polycondensation of 5,5’,6,6’- Tetrahydroxy-3,3,30,30- tetramethyl spirobisindane with 1,4- Dicyanotetrafluorobe nzene;Naiying Du et.al,;《Macromol. Rapid Commun》;20081231;第785-786页 *
偶联剂对纳米二氧化-PDMS复合渗透汽化膜性能影响的研究;兰永强;《万方学位论文数据库》;20150520;第17-19、28-48页 *

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