An organic composite film, a method for preparing the same, and an application thereof

Abstract

The application provides an organic composite film and a preparation method and application thereof. The organic composite film comprises a polymer polymerization film layer and an organic silicon film layer coated on the polymer polymerization film layer, wherein the organic silicon film layer contains molecular sieves and a hydrolysis-polycondensation product of an organic siloxane; the molecular sieves comprise one or more of Y molecular sieves, ZSM-5 molecular sieves, MCM molecular sieves and NaA molecular sieves; and the organic siloxane comprises one or more of compounds shown in formula 1 and formula 2. The organic composite film can efficiently separate and recover VOCs and has high separation selectivity.

Description

Technical Field

[0001] This invention relates to the field of membrane separation technology, specifically to an organic composite membrane, its preparation method, and its application. Background Technology

[0002] In recent years, with increasingly stringent requirements for energy conservation and environmental protection, there has been a growing demand for improving the utilization rate of added value in chemical plants. It is well known that the production, storage, and transportation of chemical products generate large amounts of tail gas, waste gas, and organic gases rich in VOCs. Direct emission of these organic gases would cause environmental pollution. Currently, combustion and activated carbon adsorption are commonly used to meet emission standards. Combustion produces more carbon dioxide, failing to meet current carbon emission requirements. While adsorption can meet these requirements, it is limited by the adsorption capacity of the adsorbent, requiring frequent replacement. Furthermore, the regeneration and subsequent treatment of the adsorbent present significant economic and environmental challenges. Therefore, membrane adsorption separation technology has gained increasing attention. Membrane adsorption separation technology is low-cost, green, efficient, low-carbon, environmentally friendly, energy-saving, and can separate and recycle waste VOCs, generating greater economic benefits.

[0003] VOCs (Volatile Organic Compounds) separation membranes utilize the adsorption and desorption of organic gas molecules by rubbery polymers on the membrane surface through similar compatibility, followed by rapid diffusion through cross-linked pores and preferential permeation through the membrane. In membrane adsorption separation technology, the membrane material is the core component and the key to achieving VOCs separation. Gas separation membranes can be classified into organic and inorganic membranes based on their raw materials. Inorganic membranes generally offer better performance, with advantages such as high mechanical strength and good thermal stability, but their manufacturing processes are complex, costly, and have poor reproducibility, making large-scale industrial application challenging. Organic membranes offer advantages such as low cost, good performance, and good ductility, and have been widely used in industry, but they also suffer from poor stability and low mechanical strength. Furthermore, organic membranes currently exhibit relatively low separation efficiency in the separation and recovery of VOCs. Summary of the Invention

[0004] To address the poor separation performance of VOCs separation membranes in existing technologies, this invention provides an organic composite membrane. By adding a certain amount of molecular sieve to the rubbery organosilicon membrane layer, the organic membrane exhibits strong adsorption capacity and higher selectivity for organic matter, significantly improving its VOCs separation and recovery capabilities. This invention also provides a method for preparing this organic composite membrane and its application in VOCs separation.

[0005] A first aspect of the present invention provides an organic composite membrane comprising a polymer-based membrane layer and an organosilicon membrane layer coated on the polymer-based membrane, wherein the organosilicon membrane layer contains a molecular sieve and a hydrolysis-condensation product of an organosiloxane; the molecular sieve comprises one or more of Y molecular sieve, ZSM-5 molecular sieve, MCM molecular sieve, and NaA molecular sieve; the organosiloxane comprises one or more of the compounds shown in Formula 1 and Formula 2:

[0006]

[0007] In Formula 1, R1 is selected from C1-C10 alkyl or C6-C20 aryl; R a R b and R c Each is independently selected from C1-C10 alkyl groups;

[0008] In Formula 2, R2 is selected from C1-C10 alkylene, C2-C10 alkenylene, or C6-C20 aryleneene; R a R b R c R d R e and R f Each is independently selected from C1-C10 alkyl groups.

[0009] According to some embodiments of the present invention, in the molecular sieve, the molar ratio Al2O3 / SiO2 is 0.005-2, for example, 0.005, 0.008, 0.01, 0.02, 0.05, 0.08, 0.1, 0.2, 0.5, 0.8, 1, 1.2, 1.5, 1.8, 2, or any value between them. In some embodiments, in the molecular sieve, the molar ratio Al2O3 / SiO2 is 0.005-1.0. In some embodiments, in the molecular sieve, the molar ratio Al2O3 / SiO2 is 0.005-0.5. In some embodiments, in the molecular sieve, the molar ratio Al2O3 / SiO2 is 0.005-0.2. In some embodiments, in the molecular sieve, the molar ratio Al2O3 / SiO2 is 0.01-0.2. In some embodiments, the molar ratio of Al2O3 / SiO2 in the molecular sieve is 0.01-0.1.

[0010] According to some embodiments of the present invention, the average particle size of the molecular sieve is 0.3-50 nm, preferably 0.5-20 nm. According to some embodiments of the present invention, the average particle size of the molecular sieve is 5-15 nm.

[0011] According to some embodiments of the present invention, the mass ratio of the molecular sieve to the organosiloxane is 1:(40-200), for example, 1:40, 1:45, 1:48, 1:50, 1:80, 1:100, 1:120, 1:150, 1:180, 1:200, or any value between them. According to some embodiments of the present invention, the mass ratio of the molecular sieve to the organosiloxane is 1:(45-150). According to some embodiments of the present invention, the mass ratio of the molecular sieve to the organosiloxane is 1:(45-120).

[0012] According to some embodiments of the present invention, the molecular sieve includes Y molecular sieve and / or ZSM-5 molecular sieve. According to some embodiments of the present invention, the molecular sieve includes Y molecular sieve.

[0013] According to some embodiments of the present invention, in Formula 1, R1 is selected from C1-C4 alkyl or C6-C10 aryl, preferably methyl, ethyl, or phenyl. According to some embodiments of the present invention, in Formula 1, R... a R b and R c Each is independently selected from C1-C4 alkyl groups, preferably methyl or ethyl.

[0014] According to some embodiments of the present invention, in Formula 2, R2 is selected from C1-C4 alkylene, C2-C4 alkenylene, or C6-C10 arylene, preferably methylene, ethylene, or vinylene. According to some embodiments of the present invention, in Formula 2, R... a R b R c R d R e R f Each is independently selected from C1-C4 alkyl groups, preferably methyl or ethyl.

[0015] According to some embodiments of the present invention, the organosiloxane includes one or more of methyltriethoxysilane, 1,2-bis(triethoxysilyl)methane, 1,2-bis(triethoxysilyl)ethane, 1,2-di(triethoxysilyl)ethylene, and phenyltriethoxysilane. According to some embodiments of the present invention, the organosiloxane includes methyltriethoxysilane.

[0016] According to some embodiments of the present invention, the hydrolysis-condensation product of the siloxane contains repeating structural units shown in Formulas 3 and 4:

[0017]

[0018] The definition of R1 is the same as that in Equation 1 of the present invention; the definition of R2 is the same as that in Equation 2 of the present invention.

[0019] According to some embodiments of the present invention, the hydrolysis-condensation product of the organosiloxane is obtained by heating the organosiloxane in the presence of an alcohol, water, and an acidic catalyst. In some embodiments, the alcohol includes one or more of methanol, ethanol, n-propanol, and isopropanol. In some embodiments, the mass ratio of the alcohol to the organosiloxane is (5-100):1, for example, 5:1, 10:1, 20:1, 30:1, 40:1, 50:1, 60:1, 70:1, 80:1, 90:1, 100:1, or any value between them, preferably (10-50):1. In some embodiments, the acidic catalyst includes an inorganic acid, preferably hydrochloric acid. In some embodiments, the molar ratio of the organosiloxane, water, and acidic catalyst is 1:(30-120):(0.05-1), preferably 1:(50-90):(0.1-0.5). In some embodiments, the heating temperature is 15-100°C, preferably 40-90°C. In some embodiments, the reaction time is 1-6 hours.

[0020] According to some embodiments of the present invention, the polymer comprises one or more of polysulfone, polyethersulfone, sulfonated polyethersulfone, polyimide, polyvinyl alcohol, and polypropylene. According to some embodiments of the present invention, the thickness of the polymer base film is 50-100 μm. According to some embodiments of the present invention, the thickness of the silicone film is 80-250 nm.

[0021] A second aspect of the present invention provides a method for preparing an organic composite membrane, comprising the following steps:

[0022] (1) The organosiloxane was heated and reacted in the presence of alcohol, water and acid catalyst to obtain the first organosilicone sol;

[0023] (2) Mix the molecular sieve with the organosilicon sol and heat to obtain a second organosilicon sol;

[0024] (3) The second organosilicon sol is coated onto a polymer base film to obtain the organic composite film;

[0025] The molecular sieve includes one or more of Y molecular sieve, ZSM-5 molecular sieve, MCM molecular sieve, and NaA molecular sieve; the organosiloxane includes one or more of the compounds shown in Formula 1 and Formula 2 below:

[0026]

[0027] In Formula 1, R1 is selected from C1-C10 alkyl or C6-C20 aryl; R a R b and R cEach is independently selected from C1-C10 alkyl groups;

[0028] In Formula 2, R2 is selected from C1-C10 alkylene, C2-C10 alkenylene, or C6-C20 aryleneene; R a R b R c R d R e and R f Each is independently selected from C1-C10 alkyl groups.

[0029] According to some embodiments of the present invention, in Formula 1, R1 is selected from C1-C4 alkyl or C6-C10 aryl, preferably methyl, ethyl, or phenyl. According to some embodiments of the present invention, in Formula 1, R... a R b and R c Each is independently selected from C1-C4 alkyl groups, preferably methyl or ethyl.

[0030] According to some embodiments of the present invention, in Formula 2, R2 is selected from C1-C4 alkylene, C2-C4 alkenylene, or C6-C10 arylene, preferably methylene, ethylene, or vinylene. According to some embodiments of the present invention, in Formula 2, R... a R b R c R d R e R f Each is independently selected from C1-C4 alkyl groups, preferably methyl or ethyl.

[0031] According to some embodiments of the present invention, the organosiloxane includes one or more of methyltriethoxysilane, 1,2-bis(triethoxysilyl)methane, 1,2-bis(triethoxysilyl)ethane, 1,2-di(triethoxysilyl)ethylene, and phenyltriethoxysilane, preferably including methyltriethoxysilane.

[0032] According to some embodiments of the present invention, in the molecular sieve, the molar ratio Al2O3 / SiO2 is 0.005-2, for example, 0.005, 0.008, 0.01, 0.02, 0.05, 0.08, 0.1, 0.2, 0.5, 0.8, 1, 1.2, 1.5, 1.8, 2, or any value between them. In some embodiments, in the molecular sieve, the molar ratio Al2O3 / SiO2 is 0.005-1.0. In some embodiments, in the molecular sieve, the molar ratio Al2O3 / SiO2 is 0.005-0.5. In some embodiments, in the molecular sieve, the molar ratio Al2O3 / SiO2 is 0.005-0.2. In some embodiments, in the molecular sieve, the molar ratio Al2O3 / SiO2 is 0.01-0.2. In some embodiments, the molar ratio of Al2O3 / SiO2 in the molecular sieve is 0.01-0.1.

[0033] According to some embodiments of the present invention, the average particle size of the molecular sieve is 0.3-50 nm, preferably 0.5-20 nm. In some embodiments, the average particle size of the molecular sieve is 5-15 nm.

[0034] According to some embodiments of the present invention, the molecular sieve includes one or both of Y-type molecular sieve and ZSM-5 molecular sieve. According to some embodiments of the present invention, the molecular sieve includes Y-type molecular sieve.

[0035] According to some embodiments of the present invention, in step (1), the alcohol includes one or more of methanol, ethanol, n-propanol, and isopropanol.

[0036] According to some embodiments of the present invention, in step (1), the mass ratio of the alcohol to the organosiloxane is (5-100):1, preferably (10-50):1.

[0037] According to some embodiments of the present invention, in step (1), the acidic catalyst comprises an inorganic acid, preferably hydrochloric acid.

[0038] According to some embodiments of the present invention, in step (1), the molar ratio of the organosiloxane, water, and acidic catalyst is 1:(30-120):(0.05-1), preferably 1:(50-90):(0.1-0.5).

[0039] According to some embodiments of the present invention, in step (1), the heating temperature is 15-100°C, preferably 40-90°C. According to some embodiments of the present invention, in step (1), the reaction time is 1-6 hours.

[0040] According to some embodiments of the present invention, in step (2), the mass ratio of the molecular sieve to the organosiloxane is 1:(40-200), for example, 1:40, 1:45, 1:48, 1:50, 1:80, 1:100, 1:120, 1:150, 1:180, 1:200, or any value between them. According to some embodiments of the present invention, in step (2), the mass ratio of the molecular sieve to the organosiloxane is 1:(45-150). According to some embodiments of the present invention, in step (2), the mass ratio of the molecular sieve to the organosiloxane is 1:(45-120).

[0041] According to some embodiments of the present invention, in step (2), the heating temperature is 15-100°C, preferably 40-90°C. According to some embodiments of the present invention, in step (2), the heating time is 0.1-4 hours.

[0042] According to some embodiments of the present invention, in step (3), the polymer comprises one or more of polysulfone, polyethersulfone, sulfonated polyethersulfone, polyimide, polyvinyl alcohol, and polypropylene. In some embodiments, in step (3), the polymer comprises one or more of polysulfone, polyethersulfone, and sulfonated polyethersulfone.

[0043] According to some embodiments of the present invention, the polymer-based film is obtained by coating a casting solution containing the polymer and N-methylpyrrolidone onto a casting body and then drying it. In some embodiments, the mass ratio of the polymer to N-methylpyrrolidone in the casting solution is 0.05-0.3, for example, 0.05, 0.1, 0.15, 0.2, 0.25, 0.3 or any value between them, preferably 0.1-0.2. In some embodiments, the casting solution is prepared by adding the polymer to N-methylpyrrolidone and heating to dissolve it. In some embodiments, the heating and dissolving temperature is 50-150°C, and the heating and dissolving time is 1-5 hours. In some embodiments, the drying temperature is 50-180°C, and the drying time is 5 min-120 min.

[0044] According to some embodiments of the present invention, step (3) further includes a drying step after coating is completed, wherein the drying temperature is 60-150°C and the drying time is 10-60 min.

[0045] In this invention, the coating method includes, but is not limited to, spraying, scraping, and spin coating.

[0046] The third aspect of the present invention provides the application of the organic composite membrane described in the first aspect of the present invention or the organic composite membrane obtained by the preparation method described in the second aspect of the present invention in the adsorption, separation and recovery of VOCs.

[0047] The VOCs (volatile organic compounds) described in this invention include, but are not limited to, alkanes (straight-chain alkanes and cycloalkanes), alkenes, alkynes, benzene compounds, phenyl oxides, phenyl peroxides, alcohols, aldehydes, ethers, ketones, acids, esters, and halogenated hydrocarbons. In some embodiments, the volatile organic compounds include at least one selected from cumene, cumene hydroperoxide, propanol, acetone, benzene, toluene, xylene, formaldehyde, styrene, trichloroethylene, chloroform, trichloroethane, diisocyanate, and diisocyanate toluene. In some embodiments, the VOCs include one or more selected from benzene compounds, phenyl oxides, phenyl peroxides, alcohols, and ketones. In some embodiments, the VOCs include one or more selected from cumene, cumene hydroperoxide, propanol, and acetone.

[0048] Compared with the prior art, the present invention has the following advantages:

[0049] 1. The organic composite membrane of the present invention, by adding hydrophobic molecular sieves to the organosilicon layer, has small particle size, large specific surface area, strong affinity for organic molecules in VOCs, large adsorption capacity, and strong adsorption ability, which can significantly improve the separation and recovery ability of organic membranes for VOCs organic gases; in addition, the molecular sieves have strong hydrophobic properties, do not adsorb moisture in VOCs, and have strong hydrothermal stability.

[0050] 2. The method for preparing the organic composite membrane of the present invention involves first hydrolyzing and cross-linking an organosilicon source precursor to form a silica sol with a certain degree of cross-linking, and then directly adding a hydrophobic molecular sieve additive to the silica sol and coating it onto a polymer base membrane layer. Compared with the traditional method for preparing composite membranes, the process is simple, easy to control, avoids complicated post-processing, saves a lot of manpower and material resources, and is easy to mass-produce. Attached Figure Description

[0051] Figure 1 This is a SEM image of the polymer base film layer of the flexible organic composite membrane obtained in Example 1.

[0052] Figure 2 This is a SEM image of the organosilicon film layer of the flexible organic composite membrane obtained in Example 1. Detailed Implementation

[0053] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments and accompanying drawings. The specific embodiments described herein are for illustrative purposes only and are not intended to limit the invention in any way. Furthermore, descriptions of well-known structures and techniques are omitted in the following description to avoid unnecessarily obscuring the concepts of this disclosure. Such structures and techniques have also been described in many publications.

[0054] To address the problem of poor separation performance of VOCs organic gas separation membranes and improve their separation capabilities, this invention provides a novel method for preparing a flexible organic composite membrane. This method produces a flexible organic composite membrane with stronger selective adsorption capacity, significantly improving the membrane's ability to separate VOCs organic gases.

[0055] According to a specific embodiment of the present invention, the method for preparing the organic composite membrane includes the following steps:

[0056] a. Preparation of polymer-based film layer

[0057] (1) According to the mass ratio of organic polymer particles: N-methylpyrrolidone = 0.1-0.2, weigh organic polymer particles (such as one of polysulfone, polyethersulfone, sulfonated polyethersulfone, polyimide, polyvinyl alcohol, and polypropylene) and add them to N-methylpyrrolidone. Dissolve them by stirring at 50-150℃ for 1-5 hours to prepare a casting solution.

[0058] (2) The casting liquid obtained in step (1) is coated onto a smooth casting body by spraying, scraping or spin coating, and dried at 60-150℃ for 10-60 minutes to obtain a polymer base film with a thickness of 50-100μm.

[0059] b. Preparation of organosilicon film

[0060] (1) Using an oxygen-containing silane (such as methyltriethoxysilane, 1,2-bis(triethoxysilyl)methane, 1,2-bis(triethoxysilyl)ethane, 1,2-bis(triethoxysilyl)ethylene and phenyltriethoxysilyl) as an organosilicon source precursor, add it to an alcohol of one or more of methanol, ethanol, n-propanol and isopropanol. The mass ratio of the alcohol added to the organosilicon source precursor is (10-50):1. Then, under stirring conditions at a temperature of 40-90℃, a certain amount of deionized water is added dropwise. Then, hydrochloric acid is gradually added dropwise. The molar ratio of hydrogen chloride in the organosilicon source precursor, deionized water and hydrochloric acid is 1:(50-90):(0.1-0.5). After stirring for 2-4 hours, an organosilicon sol is obtained.

[0061] (2) According to the mass ratio of additive R to organosilicon sol of 1:(50-100), add additive R (one or more of Y molecular sieve, ZSM5 molecular sieve, MCM molecular sieve, NaA molecular sieve, molecular sieve Al2O3 / SiO2=0.005-2, and the average particle size of additive R is 0.5-20nm) to the organosilicon sol in step (1), heat the mixture at 40-90℃ and stir for 0.2-1 hours to prepare a blended organosilicon sol gel solution;

[0062] (3) The blended organosilicon sol-gel liquid obtained in step (2) is coated onto the organic flexible base film obtained in step a by spraying, scraping or spin coating. After drying at 60-150℃ for 10-60 minutes, an organosilicon film layer is obtained. Depending on the film formation, this process can be repeated 2-5 times to make the thickness of the organosilicon film layer 80-250nm, and finally a flexible organic composite film is obtained.

[0063] The following embodiments and accompanying drawings are provided to aid in understanding the present invention. However, it should be understood that these embodiments and drawings are for illustrative purposes only and do not constitute any limitation. The actual scope of protection of the present invention is set forth in the claims. It should be understood that any modifications and changes can be made without departing from the spirit of the present invention.

[0064]

Example 1

[0065] a(1): Weigh 10g of polyethersulfone and add it to 59g of N-methylpyrrolidone solution. Stir for 4 hours under a water bath at 75℃ until the particles are completely dissolved to prepare a 14.5% (wt) casting solution.

[0066] a(2): Fix the cleaned copper foil sheet (10cm×10cm) on the coating machine, adjust the film thickness to 50-100μm, weigh 5mL of the casting solution obtained in step a(1) and evenly coat it on one end of the copper foil sheet, then turn on the machine to scrape the film. Dry the film at 100℃ for 10min to obtain the polymer base film. SEM image as follows: Figure 1 As shown.

[0067] b(1): Weigh 14.8g of methyltriethoxysilane, add 300g of isopropanol, add 120g of deionized water dropwise under a 60℃ water bath, add 4g of 10% (mass concentration) hydrochloric acid dropwise, stir for 4 hours, add 0.15g of Y molecular sieve with an average particle size of 10nm, the Al2O3 / SiO2 of the molecular sieve is 0.05, continue stirring for 1 hour to prepare a blended organosilicon sol-gel solution.

[0068] b(2): Weigh 50g of the blended organosilicon sol-gel liquid prepared in step b(1), and spray it onto the polymer base film prepared in step a(2) using electrostatic spraying to obtain an organosilicon film layer with a thickness of 80-250nm. Spraying conditions: electrostatic voltage of 80kV, nozzle height of 10cm, gas flow rate of 125mL / min, and nozzle moving speed of 9cm / s; dry at 100℃ for 30min to prepare a flexible organic composite film. The SEM image of the organosilicon film layer on the surface is shown below. Figure 2 As shown.

[0069]

Example 2

[0070] The difference from Example 1 is that "Y molecular sieve with an average particle size of 10 nm" is replaced with "ZSM-5 molecular sieve with an average particle size of 10 nm", and Al2O3 / SiO2 = 0.05.

[0071]

Example 3

[0072] The difference from Example 1 is that "Y molecular sieve with an average particle size of 10 nm" is replaced with "MCM molecular sieve with an average particle size of 10 nm", and Al2O3 / SiO2 = 0.05.

[0073]

Example 4

[0074] The difference from Example 1 is that “methyltriethoxysilane” is replaced with “1,2-bis(triethoxysilyl)methane”.

[0075]

Example 5

[0076] The difference from Example 1 is that “methyltriethoxysilane” is replaced with “1,2-bis(triethoxysilyl)ethylene”.

[0077]

Example 6

[0078] The difference from Example 1 is that "methyltriethoxysilane" is replaced with "phenyltriethoxysilane".

[0079]

Example 7

[0080] The difference from Example 1 is that the amount of Y molecular sieve is replaced with "0.3g" instead of "0.15g".

[0081]

Example 8

[0082] The difference from Example 1 is that the amount of Y molecular sieve is replaced with "0.075g" instead of "0.15g".

[0083]

Example 9

[0084] The difference from Example 1 is that "Y molecular sieve with Al2O3 / SiO2 (molar ratio) = 0.05" is replaced with "Y molecular sieve with Al2O3 / SiO2 (molar ratio) = 0.5".

[0085]

Example 10

[0086] The difference from Example 1 is that "Y molecular sieve with Al2O3 / SiO2 (molar ratio) = 0.05" is replaced with "Y molecular sieve with Al2O3 / SiO2 (molar ratio) = 0.01".

[0087]

Example 11

[0088] The difference from Example 1 is that "Y molecular sieve with Al2O3 / SiO2 (molar ratio) = 0.05" is replaced with "Y molecular sieve with Al2O3 / SiO2 (molar ratio) = 0.2".

[0089]

Example 12

[0090] The difference from Example 1 is that "Y molecular sieve with Al2O3 / SiO2 (molar ratio) = 0.05" is replaced with "Y molecular sieve with Al2O3 / SiO2 (molar ratio) = 2".

[0091]

Example 13

[0092] The difference from Example 1 is that “Y molecular sieve” is replaced with “NaA molecular sieve with an average particle size of 10 nm and an Al2O3 / SiO2 (molar ratio) of 0.05”.

[0093] Comparative Example 1

[0094] The only difference from Example 1 is that Y molecular sieve is not added in step b(1).

[0095] Comparative Example 2

[0096] The only difference from Example 1 is that "methyltriethoxysilane" is replaced with "dimethyltriethoxysilane".

[0097] Comparative Example 3

[0098] The difference from Example 1 is that "methyltriethoxysilane" is replaced with "trimethylethoxysilane".

[0099] Comparative Example 4

[0100] a(1): Weigh 10g of polytetrafluoroethylene and add it to 59g of N-methylpyrrolidone solution. Stir for 4 hours under a water bath at 75℃ until the particles are completely dissolved to prepare a 14.5% (wt) casting solution.

[0101] a(2): Fix the cleaned copper foil (10cm×10cm) on the coating machine, adjust the film thickness to 50-100μm, weigh 5mL of the casting solution obtained in step a(1) and coat it evenly on one end of the copper foil, then turn on the machine to scrape the film. Dry the film at 100℃ for 10min to obtain the polymer base film.

[0102] b(1): 0.15 g of NaA molecular sieve with an average particle size of 10 nm (Al2O3 / SiO2=0.05) was added to 100 g of n-hexane and stirred at 35 °C for 2 h to obtain a well dispersed suspension.

[0103] b(2): 10g of polydimethylsiloxane (PDMS), 2g of tetraethyl orthosilicate and 0.1g of catalyst dibutyltin dilaurate were added to the well dispersed suspension prepared in b(1) above. After stirring for 2 hours and allowing to stand to remove bubbles, organosilicon sol-gel liquid was obtained.

[0104] b(3): Weigh 50g of the organosilicon sol gel liquid prepared in step b(2) and spray it onto the polymer base film prepared in step a(2) by electrostatic spraying to obtain an organosilicon film layer with a thickness of 80-250nm. Spraying conditions: electrostatic voltage of 80kV, nozzle height of 10cm, gas flow rate of 125mL / min, and nozzle moving speed of 9cm / s; dry at 100℃ for 30min to prepare a flexible organic composite film.

[0105] Comparative Example 5

[0106] The difference from Comparative Example 4 is that “polytetrafluoroethylene” in step a(1) is replaced with “PVDF”.

[0107] Comparative Example 6

[0108] The difference from Comparative Example 4 is that “polytetrafluoroethylene” in step a(1) is replaced with “PP”, and “NaA molecular sieve” in step b(1) is replaced with “ZSM-5 molecular sieve”.

[0109] VOCs separation effect test

[0110] The flexible organic composite membranes prepared in the above examples and comparative examples were used to test the VOCs oil-gas separation performance. Test conditions: at room temperature (e.g., 25°C), with nitrogen entrainment at 5 g / m³. 3 The feed gas consists of VOCs-laden oil and gas (containing cumene, cumene hydroperoxide, propanol, acetone, etc.). The feed gas pressure is 0.30 MPa, and the feed flow rate is 0.30 L / m³. 2 The permeate side vacuum degree is 0.08 MPa, and the VOCs concentration in the permeate side after membrane separation is ag / m³. 3The concentration of VOCs from the intercepted side was bg / m³. 3 The membrane separation selectivity is X = a / b.

[0111] Oil and gas concentrations were determined using an Agilent 7890B gas chromatograph. Chromatographic conditions: HP-5 column, injection port temperature 120℃, column temperature 80-200℃, detector: FID detector, temperature 250℃, carrier gas (N2) flow rate 50 mL / min, H2 flow rate 40 mL / min, air flow rate 300 mL / min, make-up gas flow rate 10 mL / min; valve injection volume 0.5 mL.

[0112] The test results are shown in Table 1.

[0113] Table 1

[0114]

[0115]

[0116] The technical solutions of the present invention are not limited to the specific embodiments described above. Any technical modifications made in accordance with the technical solutions of the present invention fall within the protection scope of the present invention.

Claims

1. An organic composite membrane, comprising a polymer-based film layer and an organosilicon film layer coated on the polymer-based film layer, wherein, The organosilicon membrane contains molecular sieves and hydrolysis-condensation products of organosiloxanes; the molecular sieves include one or more of Y molecular sieves, ZSM-5 molecular sieves, MCM molecular sieves, and NaA molecular sieves; the organosiloxanes include one or more of the compounds shown in Formula 1 and Formula 2 below: In Formula 1, R1 is selected from C1-C10 alkyl or C6-C20 aryl; R a R b and R c Each is independently selected from C1-C10 alkyl groups; In Formula 2, R2 is selected from C1-C10 alkylene, C2-C10 alkenylene, or C6-C20 arylene; R a R b R c R d R e and R f Each is independently selected from C1-C10 alkyl groups.

2. The organic composite membrane according to claim 1, characterized in that, In the molecular sieve, the molar ratio Al2O3 / SiO2 is 0.005-2, preferably 0.005-0.5, more preferably 0.01-0.2, and even more preferably 0.01-0.1; and / or, The molecular sieve has an average particle size of 0.3-50 nm, preferably 0.5-20 nm; and / or, The mass ratio of the molecular sieve to the organosiloxane is 1:(40-200), preferably 1:(45-150), more preferably 1:(45-120); and / or, The molecular sieve includes Y molecular sieve and / or ZSM-5 molecular sieve, more preferably Y molecular sieve.

3. The organic composite membrane according to claim 1 or 2, characterized in that, In Formula 1, R1 is selected from C1-C4 alkyl or C6-C10 aryl, preferably methyl, ethyl or phenyl; R a R b and R c Each is independently selected from C1-C4 alkyl groups, preferably methyl or ethyl; In Formula 2, R2 is selected from C1-C4 alkylene, C2-C4 alkenylene, or C6-C10 arylene, preferably methylene, ethylene, or vinylene; R a R b R c R d R e R f Each is independently selected from C1-C4 alkyl groups, preferably methyl or ethyl; Preferably, the organosiloxane includes one or more of methyltriethoxysilane, 1,2-bis(triethoxysilyl)methane, 1,2-bis(triethoxysilyl)ethane, 1,2-di(triethoxysilyl)ethylene, and phenyltriethoxysilane.

4. The organic composite membrane according to any one of claims 1-3, characterized in that, The hydrolysis-condensation product of the siloxane contains repeating structural units shown in Formulas 3 and 4: Where R1 is defined as in Equation 1; R2 is defined as in Equation 2; Preferably, the hydrolysis-condensation product of the organosiloxane is obtained by heating the organosiloxane in the presence of alcohol, water and an acidic catalyst; Preferably, the alcohol includes one or more of methanol, ethanol, n-propanol, and isopropanol; Preferably, the mass ratio of the alcohol to the organosiloxane is (5-100):1, more preferably (10-50):1; Preferably, the acidic catalyst comprises an inorganic acid, and more preferably hydrochloric acid; Preferably, the molar ratio of the organosiloxane, water, and acidic catalyst is 1:(30-120):(0.05-1), and more preferably 1:(50-90):(0.1-0.5). Preferably, the heating temperature is 15-100℃, more preferably 40-90℃; the reaction time is 1-6 hours.

5. The organic composite membrane according to any one of claims 1-4, characterized in that, The polymer comprises one or more of polysulfone, polyethersulfone, sulfonated polyethersulfone, polyimide, polyvinyl alcohol, and polypropylene; and / or, The thickness of the polymer-based film layer is 50-100 μm; and / or, The thickness of the organosilicon film is 80-250 nm.

6. A method for preparing an organic composite membrane, comprising the following steps: (1) The organosiloxane was heated and reacted in the presence of alcohol, water and acid catalyst to obtain the first organosilicone sol; (2) Mix the molecular sieve with the first organosilicon sol and heat to obtain the second organosilicon sol; (3) The second organosilicon sol is coated onto a polymer base film to obtain the organic composite film; in, The molecular sieve includes one or more of Y molecular sieve, ZSM-5 molecular sieve, MCM molecular sieve, and NaA molecular sieve; the organosiloxane includes one or more of the compounds shown in Formula 1 and Formula 2 below: In Equation 1, R1 and R a R b and R c The definition is the same as that in claim 1 or 3; In Equation 2, R2 and R a R b R c R d R e and R f The definition is the same as that in claim 1 or 3.

7. The preparation method according to claim 6, characterized in that, In the molecular sieve, the molar ratio Al2O3 / SiO2 is 0.005-2, preferably 0.005-0.5, more preferably 0.01-0.2, and even more preferably 0.01-0.1; and / or, The molecular sieve has an average particle size of 0.3-50 nm, preferably 0.5-20 nm; And / or, the molecular sieve includes one or both of Y molecular sieve and ZSM-5 molecular sieve; and / or, The organosiloxane includes one or more of methyltriethoxysilane, 1,2-bis(triethoxysilyl)methane, 1,2-bis(triethoxysilyl)ethane, 1,2-di(triethoxysilyl)ethylene, and phenyltriethoxysilane, preferably including methyltriethoxysilane.

8. The preparation method according to claim 6 or 7, characterized in that, In step (1), the alcohol includes one or more of methanol, ethanol, n-propanol, and isopropanol; and / or, The mass ratio of the alcohol to the organosiloxane is (5-100):1, preferably (10-50):1; and / or, The acidic catalyst comprises an inorganic acid, preferably hydrochloric acid; and / or, The molar ratio of the organosiloxane, water, and acidic catalyst is 1:(30-120):(0.05-1), preferably 1:(50-90):(0.1-0.5); and / or, The heating temperature is 15-100℃, preferably 40-90℃; the reaction time is 1-6 hours.

9. The preparation method according to any one of claims 6-8, characterized in that, In step (2), the mass ratio of the molecular sieve to the organosiloxane is 1:(40-200), preferably 1:(45-150), more preferably 1:(45-120); and / or, The heating temperature is 15-100℃, preferably 40-90℃; the heating time is 0.1-4 hours; and / or, In step (3), the polymer includes one or more of polysulfone, polyethersulfone, sulfonated polyethersulfone, polyimide, polyvinyl alcohol, and polypropylene; Preferably, the polymer-based film is obtained by coating a casting solution containing the polymer and N-methylpyrrolidone onto a casting body and then drying it. Preferably, in the casting solution, the mass ratio of the polymer to N-methylpyrrolidone is 0.05-0.

3.

10. The application of the organic composite membrane according to any one of claims 1-5 or the organic composite membrane obtained by the preparation method according to any one of claims 6-9 in the adsorption, separation and recovery of VOCs; Preferably, the VOCs include one or more of the following: alkanes, cycloalkanes, alkenes, alkynes, benzene compounds, phenyl oxides, phenyl peroxides, alcohols, aldehydes, ethers, ketones, acids, esters, and halogenated hydrocarbons. Preferably, the VOCs include one or more of benzene compounds, phenyl oxides, phenyl peroxides, alcohols, and ketones; Preferably, the VOCs include one or more of cumene, cumene hydroperoxide, propanol, and acetone.

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