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CN117959950A - Polyolefin-based polyamide composite membrane prepared by iso-side transmembrane anti-diffusion interfacial polymerization and preparation method thereof - Google Patents

Polyolefin-based polyamide composite membrane prepared by iso-side transmembrane anti-diffusion interfacial polymerization and preparation method thereof Download PDF

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CN117959950A
CN117959950A CN202410073910.6A CN202410073910A CN117959950A CN 117959950 A CN117959950 A CN 117959950A CN 202410073910 A CN202410073910 A CN 202410073910A CN 117959950 A CN117959950 A CN 117959950A
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薛立新
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    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01DSEPARATION
    • B01D69/00Semi-permeable membranes for separation processes or apparatus characterised by their form, structure or properties; Manufacturing processes specially adapted therefor
    • B01D69/12Composite membranes; Ultra-thin membranes
    • B01D69/125In situ manufacturing by polymerisation, polycondensation, cross-linking or chemical reaction
    • B01D69/1251In situ manufacturing by polymerisation, polycondensation, cross-linking or chemical reaction by interfacial polymerisation
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01DSEPARATION
    • B01D67/00Processes specially adapted for manufacturing semi-permeable membranes for separation processes or apparatus
    • B01D67/0081After-treatment of organic or inorganic membranes
    • B01D67/0088Physical treatment with compounds, e.g. swelling, coating or impregnation
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01DSEPARATION
    • B01D69/00Semi-permeable membranes for separation processes or apparatus characterised by their form, structure or properties; Manufacturing processes specially adapted therefor
    • B01D69/12Composite membranes; Ultra-thin membranes
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01DSEPARATION
    • B01D71/00Semi-permeable membranes for separation processes or apparatus characterised by the material; Manufacturing processes specially adapted therefor
    • B01D71/06Organic material
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    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
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    • B01D71/00Semi-permeable membranes for separation processes or apparatus characterised by the material; Manufacturing processes specially adapted therefor
    • B01D71/06Organic material
    • B01D71/56Polyamides, e.g. polyester-amides
    • CCHEMISTRY; METALLURGY
    • C02TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02FTREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00Treatment of water, waste water, or sewage
    • C02F1/44Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis
    • C02F1/441Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis by reverse osmosis
    • CCHEMISTRY; METALLURGY
    • C02TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02FTREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00Treatment of water, waste water, or sewage
    • C02F1/44Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis
    • C02F1/442Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis by nanofiltration
    • CCHEMISTRY; METALLURGY
    • C02TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02FTREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00Treatment of water, waste water, or sewage
    • C02F1/44Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis
    • C02F1/445Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis by forward osmosis
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
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    • B01D2323/00Details relating to membrane preparation
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    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
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    • BPERFORMING OPERATIONS; TRANSPORTING
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    • B01D69/12Composite membranes; Ultra-thin membranes
    • B01D69/1216Three or more layers
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01DSEPARATION
    • B01D71/00Semi-permeable membranes for separation processes or apparatus characterised by the material; Manufacturing processes specially adapted therefor
    • B01D71/06Organic material
    • B01D71/30Polyalkenyl halides
    • B01D71/32Polyalkenyl halides containing fluorine atoms
    • B01D71/34Polyvinylidene fluoride
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01DSEPARATION
    • B01D71/00Semi-permeable membranes for separation processes or apparatus characterised by the material; Manufacturing processes specially adapted therefor
    • B01D71/06Organic material
    • B01D71/30Polyalkenyl halides
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Abstract

The invention discloses a polyolefin-based polyamide composite membrane prepared by opposite-side transmembrane anti-diffusion interfacial polymerization and a preparation method thereof, wherein the composite membrane comprises the following components: a porous polyolefin support layer, a polyamide composite layer obtained by the reverse diffusion interfacial polymerization of an opposite-side transmembrane inside the porous polyolefin support layer, and a surfactant. The preparation method comprises the following steps: preparing aqueous solution of polyamine as aqueous phase solution, adding surfactant into the aqueous phase solution, and preparing alkane solution of aromatic acyl chloride as organic phase solution; the water phase solution is cast on any side surface of the porous polyolefin support material, the organic phase solution is cast on the other side surface (two modes can be divided according to the casting order), and after a period of time of polymerization through a back diffusion interface, the redundant solution is removed; and carrying out heat treatment at a certain temperature to obtain the polyolefin-based polyamide composite membrane. The polyolefin-based polyamide composite membrane prepared by the invention has the characteristics of low cost, high performance and high selectivity, and can be used as a water treatment membrane for forward osmosis, nanofiltration, reverse osmosis and the like.

Description

Polyolefin-based polyamide composite membrane prepared by iso-side transmembrane anti-diffusion interfacial polymerization and preparation method thereof
Technical Field
The invention relates to a polyolefin-based polyamide composite membrane and a preparation method thereof, in particular to a polyolefin-based polyamide composite membrane prepared by iso-side transmembrane back-diffusion interfacial polymerization and a preparation method thereof, belonging to the technical field of membrane separation.
Background
Polysulfone (PSF) -based polyamide multilayer composite membranes are the most commercially successful membranes. The membrane can be widely used as a reverse osmosis membrane, a nanofiltration membrane and a forward osmosis membrane in the water treatment processes of sea water brackish water desalination, sewage treatment, drinking water purification and the like. Forward Osmosis (FO for short) is a membrane separation process that uses the osmotic pressure difference of a solution on both sides of a Forward Osmosis membrane as a driving force to diffuse water molecules from the side of high chemical potential (raw material liquid) to the side of low chemical potential (draw liquid). The FO process has the advantages of low energy consumption, high recovery rate, relatively low membrane pollution and the like, and is mainly applied to the fields of emergency clean drinking, sea water desalination, food concentration, medicine control, fixed-point release and the like. Because of the many advantages of the FO process, future use may be possible in more industrial applications instead of conventional technology.
Polysulfone and polyether sulfone basement membrane carriers used in traditional Polysulfone (PSF) based polyamide multilayer composite membranes are relatively hydrophilic, and although suitable for interfacial polymerization, polysulfone layers are high in cost, and the preparation process adopts a phase inversion process, so that the polysulfone layer is complex and not environment-friendly, and therefore, the exploration of other basement membrane materials is necessary. Polyethylene lithium ion battery separator (PE) is a thermoplastic resin produced by polymerization of ethylene, and PE has advantages of low cost, excellent mechanical and chemical robustness, low mass transport resistance due to its highly open and interconnected pore structure, etc., so PE membranes have been the most dominant commercial separator, and in recent years researchers have used PE membranes as the base membranes of separation membranes, polysulfone (PSF) -based polyamide multilayer composite membranes can be obtained by using co-lateral normal phase and reverse phase interfacial polymerization, but since the obtained polyamide separation layers are distributed on the surface of polyolefin base membranes, the obtained separation layers have low water flux, and are easily defective and detached, affecting interception and long-term use stability. It is necessary to explore a novel interfacial polymerization process to obtain polyamide multilayer composite membranes with high pipe throughput, high salt rejection and high stability.
Disclosure of Invention
In order to solve the defects of the technology, the invention provides a polyolefin-based polyamide composite membrane prepared by reverse diffusion interface polymerization of an opposite-side transmembrane and a preparation method thereof, which mainly solve the problems of high cost, low flux and easy falling-off and defects of the existing PSF/PA membrane prepared by the same-side interface polymerization, and aim to prepare a novel high-selectivity polyolefin-polyamide membrane by the reverse diffusion interface polymerization of the opposite-side transmembrane, and generate a polyamide layer in the polyolefin membrane by the reverse diffusion, thereby being mainly applicable to the water treatment fields of forward osmosis, reverse osmosis, nanofiltration and the like.
In order to solve the technical problems, the invention adopts the following technical scheme: a polyolefin-based polyamide composite membrane prepared by heterolateral transmembrane back-diffusion interfacial polymerization, the composite membrane comprising: a porous polyolefin support layer, a polyamide composite layer obtained by the reverse diffusion interfacial polymerization of an opposite-side transmembrane inside the porous polyolefin support layer, and a surfactant.
Preferably, the porous polyolefin support layer is composed of one or more of polyethylene, polypropylene, polyvinylidene fluoride, polytetrafluoroethylene polymers;
preferably, the surfactant is one or more of tween 80, sodium dodecyl sulfate, cetyltrimethylammonium bromide, cetyltrimethyl-p-toluenesulfonic acid amine or derivatives thereof.
The preparation method of the polyolefin-based polyamide composite membrane prepared by the iso-side transmembrane back-diffusion interfacial polymerization comprises the following steps:
S1, preparing aqueous solution of polyamine as aqueous phase solution, adding surfactant into the aqueous phase solution, and preparing alkane solution of aromatic acyl chloride as organic phase solution for later use;
Step S2, the water phase solution or the organic phase solution prepared in the step S1 is cast on the surface of any side of the porous polyolefin support material, and after soaking for a certain time, redundant solution is removed;
Step S3, the organic phase solution or the aqueous phase solution prepared in the step S1 is cast on the surface of the other side of the porous polyolefin support material obtained in the step S2, and after a period of time of polymerization through a back diffusion interface, the redundant solution is removed;
and S4, performing heat treatment at a certain temperature to obtain the polyolefin-based polyamide composite membrane prepared by the reverse diffusion interfacial polymerization of the heterolateral transmembrane.
Preferably, in step S1, the polyamine is any one or more of m-phenylenediamine, ethylenediamine, piperazine, polyethyleneimine, or derivatives thereof.
Preferably, in step S1, the aromatic acyl chloride is one or more of trimesoyl chloride, naphthalene ring triacyl chloride, other aromatic polybasic sulfonyl chloride or derivatives thereof.
Preferably, in step S1, the alkane solvent is one or more solvents selected from n-hexane, n-pentane, isododecane and isohexadecane.
Preferably, in step S1, the concentration of the aqueous phase solution is 0.01 to 5wt%, the concentration of the surfactant in the aqueous phase solution is 0.001 to 1wt%, and the concentration of the organic phase solution is 0.001 to 1wt%.
Preferably, in step S2, the soaking time of the aqueous phase is 1-15 min, and in step S3, the contact time of the organic phase is 1-8 min.
Preferably, in the step S4, the drying temperature is 30-80 ℃ and the drying time is 5-20 min.
The heterolateral back diffusion interfacial polymerization means that aqueous phase polyamine solution containing surfactant and organic phase aromatic poly acyl chloride monomer solution are respectively poured on two sides of the polyolefin-based membrane, and a polyamide separation functional layer is formed inside by utilizing different penetration and diffusion capacities of the aqueous phase polyamine solution and the organic phase aromatic poly acyl chloride monomer solution, and the polyolefin-based polyamide composite membrane with an asymmetric surface is obtained after hydrolysis and cleaning. The polyolefin-based polyamide composite membrane prepared by the invention has the characteristics of low cost, high performance and high selectivity, and can be used as a water treatment membrane for forward osmosis, nanofiltration, reverse osmosis and the like.
Compared with the prior art, the invention has the following advantages:
(1) The invention provides a preparation method of a polyolefin-based polyamide composite membrane with low cost, high flux and high selectivity, namely, heterolateral trans-base membrane anti-diffusion interfacial polymerization.
(2) The polyethylene-polyamide composite membrane prepared by the reverse diffusion interfacial polymerization of the heterolateral transmembrane can be used as a forward osmosis membrane, a nanofiltration membrane and a reverse osmosis membrane to be applied to the field of water treatment.
Drawings
FIG. 1 is a schematic illustration of the ipsilateral transmembrane back-diffusion interfacial polymerization of the present invention: and (3) adding an organic phase and then adding an aqueous phase to form a film.
FIG. 2 is a schematic illustration of the ipsilateral transmembrane back-diffusion interfacial polymerization of the present invention: and adding the water phase and then adding the organic phase to form a film.
FIG. 3 is a flow chart of the comparative example reverse phase interfacial polymerization process of the present invention.
FIG. 4 is a flow chart of the film formation by the normal phase interfacial polymerization of the comparative example of the present invention.
FIG. 5 is a surface electron microscope scan of a Polyolefin (PE) base film used in the present invention.
FIG. 6 is a surface scanning electron microscope image of a polyethylene-polyamide composite forward osmosis membrane prepared by the present invention.
FIG. 7 is a cross-sectional N-element distribution diagram of a polyethylene-polyamide composite forward osmosis membrane prepared by the present invention.
FIG. 8 is a surface scanning electron microscope image of the polyethylene-polyamide composite nanofiltration membrane prepared by the invention.
FIG. 9 is a cross-sectional N element distribution diagram of a polyethylene-polyamide composite nanofiltration membrane prepared by the invention.
FIG. 10 is a graph showing the water contact angle of the front and back surfaces of the polyethylene-polyamide composite membrane prepared by the invention.
FIG. 11 is a graph showing the performance of the present invention in preparing polyethylene-polyamide composite forward osmosis membranes by reverse diffusion interfacial polymerization of a heterolateral transmembrane under varying concentrations of surfactant CTAT.
FIG. 12 is a graph showing the performance of the invention in preparing polyethylene-polyamide composite nanofiltration membranes by iso-side transmembrane back-diffusion interfacial polymerization under different concentrations of surfactant CTAB.
Detailed Description
The invention will be described in further detail with reference to the drawings and the detailed description.
The preparation method of the polyolefin-based polyamide composite membrane prepared by the heterolateral transmembrane back-diffusion interfacial polymerization is divided into a first method and a second method according to different casting sequences, and the two methods are different: the water phase solution and the organic phase solution are different in casting coating sequence, and the concrete operation is as follows:
method one (first casting aqueous solution, as shown in fig. 2):
(1) Preparing 2wt% of m-phenylenediamine and a water solution of hexadecyl trimethyl ammonium p-toluenesulfonate with a certain concentration as an aqueous phase solution, and preparing 0.1wt% of n-hexane solution of trimesoyl chloride as an organic phase solution for later use;
(2) Coating the aqueous phase solution prepared in the step (1) on one side surface of the PE support material, soaking for 12min, and removing redundant solution;
(3) The organic phase solution prepared in the step (1) is cast on the other side surface of the PE support material obtained in the step (2), and after polymerization for 2min through a back diffusion interface, redundant solution is removed;
(4) And (3) carrying out heat treatment at 60 ℃ for 15min to obtain the polyolefin-based polyamide composite membrane prepared by the heterolateral transmembrane back-diffusion interfacial polymerization.
Method two (first casting organic phase solution, as shown in fig. 1):
(1) Preparing 0.08wt% of anhydrous piperazine and a water solution of hexadecyl trimethyl ammonium bromide with a certain concentration as an aqueous phase solution, and preparing 0.1wt% of normal hexane solution of trimesoyl chloride as an organic phase solution for later use;
(2) Pouring the organic phase solution prepared in the step (1) on one side surface of the PE support material, soaking for 5min, and removing redundant solution;
(3) The water phase solution prepared in the step (1) is cast on the other side surface of the PE supporting material obtained in the step (2), and after polymerization for 10min through a back diffusion interface, redundant solution is removed;
(4) And (3) carrying out heat treatment at 60 ℃ for 15min to obtain the polyolefin-based polyamide composite membrane prepared by the heterolateral transmembrane back-diffusion interfacial polymerization.
The present invention will be described in further detail with reference to specific examples.
The polyethylene support film used in the following examples was supplied by Shanghai Enjetsche New Material technologies Co., ltd, model number HS16.
Examples 1-5 employed method one and examples 6-10 employed method two.
Example 1
(1) Preparing 2wt% of m-phenylenediamine, 0.05wt% of aqueous solution of hexadecyl trimethyl ammonium paratoluenesulfonate (CTAT) as an aqueous phase solution, and preparing 0.1wt% of normal hexane solution of trimesoyl chloride as an organic phase solution for later use;
(2) Coating the aqueous phase solution prepared in the step (1) on one side surface of the PE support material, soaking for 12min, and removing redundant solution;
(3) The organic phase solution prepared in the step (1) is cast on the other side surface of the support layer material obtained in the step (2), and after polymerization for 2min through a back diffusion interface, redundant solution is removed;
(4) And (3) carrying out heat treatment at 60 ℃ for 15min to obtain the polyethylene-polyamide composite membrane prepared by the reverse diffusion interfacial polymerization of the heterolateral transmembrane.
The polyethylene-polyamide composite membrane prepared in this example was put into a forward osmosis membrane performance evaluation device, then a 1mol/L aqueous sodium chloride solution was used as a draw solution, deionized water was used as a raw material solution, the membrane organic phase side was oriented to the draw solution, the measured membrane flux was 10.06L/(m 2. H), and the salt backmixing flux was 0.0211 mol/(m 2. H).
Example 2
(1) Preparing 2wt% of m-phenylenediamine, 0.075wt% of aqueous solution of hexadecyl trimethyl ammonium p-toluenesulfonate as an aqueous phase solution, and preparing 0.1wt% of n-pentane solution of trimesoyl chloride as an organic phase solution for later use;
(2) Coating the aqueous phase solution prepared in the step (1) on one side surface of the PE support material, soaking for 12min, and removing redundant solution;
(3) The organic phase solution prepared in the step (1) is cast on the other side surface of the support layer material obtained in the step (2), and after polymerization for 2min through a back diffusion interface, redundant solution is removed;
(4) And (3) carrying out heat treatment at 60 ℃ for 15min to obtain the polyethylene-polyamide composite membrane prepared by the reverse diffusion interfacial polymerization of the heterolateral transmembrane.
The polyethylene-polyamide composite membrane prepared in this example was put into a forward osmosis membrane performance evaluation device, then a 1mol/L aqueous sodium chloride solution was used as a draw solution, deionized water was used as a raw material solution, the membrane organic phase side was oriented to the draw solution, the measured membrane flux was 16.84L/(m 2. H), and the salt backmixing flux was 0.0318 mol/(m 2. H).
Example 3
(1) Preparing 5wt% of m-phenylenediamine, taking an aqueous solution of 0.1wt% of hexadecyl trimethyl ammonium p-toluenesulfonate as an aqueous phase solution, and preparing an n-hexane solution of 1wt% of trimesoyl chloride as an organic phase solution for later use;
(2) Coating the aqueous phase solution prepared in the step (1) on one side surface of the PE support material, soaking for 12min, and removing redundant solution;
(3) The organic phase solution prepared in the step (1) is cast on the other side surface of the support layer material obtained in the step (2), and after polymerization for 2min through a back diffusion interface, redundant solution is removed;
(4) And (3) carrying out heat treatment at 60 ℃ for 15min to obtain the polyethylene-polyamide composite membrane prepared by the reverse diffusion interfacial polymerization of the heterolateral transmembrane.
The polyethylene-polyamide composite membrane prepared in the embodiment is put into a forward osmosis membrane performance evaluation device, then 1mol/L sodium chloride aqueous solution is used as a drawing liquid, deionized water is used as a raw material liquid, the organic phase side of the membrane faces the drawing liquid, the measured membrane flux is 24.73L/(m 2. H), and the salt back mixing flux is 0.0346 mol/(m 2. H).
Example 4
(1) Preparing 2wt% of m-phenylenediamine, using an aqueous solution of 0.125wt% of hexadecyl trimethyl ammonium p-toluenesulfonate as an aqueous phase solution, and preparing an n-hexane solution of 0.1wt% of trimesoyl chloride as an organic phase solution for later use;
(2) Coating the aqueous phase solution prepared in the step (1) on one side surface of the PE support material, soaking for 12min, and removing redundant solution;
(3) The organic phase solution prepared in the step (1) is cast on the other side surface of the support layer material obtained in the step (2), and after polymerization for 2min through a back diffusion interface, redundant solution is removed;
(4) And (3) carrying out heat treatment at 60 ℃ for 15min to obtain the polyethylene-polyamide composite membrane prepared by the reverse diffusion interfacial polymerization of the heterolateral transmembrane.
The polyethylene-polyamide composite membrane prepared in the embodiment is put into a forward osmosis membrane performance evaluation device, then 1mol/L sodium chloride aqueous solution is used as a drawing liquid, deionized water is used as a raw material liquid, the organic phase side of the membrane faces the drawing liquid, the measured membrane flux is 22.29L/(m 2. H), and the salt back mixing flux is 0.0350 mol/(m 2. H).
Example 5
(1) Preparing 2wt% of m-phenylenediamine, using an aqueous solution of 0.15wt% of hexadecyl trimethyl ammonium p-toluenesulfonate as an aqueous phase solution, and preparing an n-hexane solution of 0.1wt% of trimesoyl chloride as an organic phase solution for later use;
(2) Coating the aqueous phase solution prepared in the step (1) on one side surface of the PE support material, soaking for 12min, and removing redundant solution;
(3) The organic phase solution prepared in the step (1) is cast on the other side surface of the support layer material obtained in the step (2), and after polymerization for 2min through a back diffusion interface, redundant solution is removed;
(4) And (3) carrying out heat treatment at 60 ℃ for 15min to obtain the polyethylene-polyamide composite membrane prepared by the reverse diffusion interfacial polymerization of the heterolateral transmembrane.
The polyethylene-polyamide composite membrane prepared in the embodiment is put into a forward osmosis membrane performance evaluation device, then 1mol/L sodium chloride aqueous solution is used as a drawing liquid, deionized water is used as a raw material liquid, the organic phase side of the membrane faces the drawing liquid, the measured membrane flux is 20.32L/(m 2. H), and the salt back-mixing flux is 0.0343 mol/(m 2. H).
Example 6
(1) Preparing an aqueous solution of 0.08wt% of anhydrous piperazine and 0.025wt% of cetyltrimethylammonium bromide (CTAB) as an aqueous phase solution, and preparing an organic phase solution of 0.1wt% of trimesoyl chloride as an n-hexane solution for later use;
(2) Pouring the organic phase solution prepared in the step (1) on one side surface of the PE support material, soaking for 5min, and removing redundant solution;
(3) The water phase solution prepared in the step (1) is cast on the other side surface of the support layer material obtained in the step (2), and after polymerization for 10min through a back diffusion interface, redundant solution is removed;
(4) And (3) carrying out heat treatment at 60 ℃ for 15min to obtain the polyolefin polyamide composite membrane prepared by the heterolateral transmembrane back-diffusion interfacial polymerization.
The polyethylene-polyamide composite membrane prepared in the embodiment is put into a nanofiltration membrane performance evaluation device, and experimental conditions are as follows: 0.6Mpa, 0.5h of prepressing and 1000ppm of sodium sulfate concentration. Experimental results: water flux: 7.14L/(m 2. H), retention: 97.5%.
Example 7
(1) Preparing an aqueous solution of 0.08 weight percent of anhydrous piperazine and 0.05 weight percent of cetyltrimethylammonium bromide (CTAB) as an aqueous phase solution, and preparing an organic phase solution of 0.1 weight percent of trimesic chloride in normal hexane;
(2) Pouring the organic phase solution prepared in the step (1) on one side surface of the PE support material, soaking for 5min, and removing redundant solution;
(3) The water phase solution prepared in the step (1) is cast on the other side surface of the support layer material obtained in the step (2), and after polymerization for 10min through a back diffusion interface, redundant solution is removed;
(4) And (3) carrying out heat treatment at 60 ℃ for 15min to obtain the polyolefin polyamide composite membrane prepared by the heterolateral transmembrane back-diffusion interfacial polymerization.
The polyethylene-polyamide composite membrane prepared in this example was loaded into a forward osmosis membrane performance evaluation device under experimental conditions: 0.6Mpa, 0.5h of prepressing and 1000ppm of sodium sulfate concentration. Experimental results: water flux: 26.46L/(m 2. H), retention: 97.3%.
Example 8
(1) Preparing an aqueous solution of 0.08 weight percent of anhydrous piperazine and 0.075 weight percent of cetyltrimethylammonium bromide (CTAB) as an aqueous phase solution, and preparing an organic phase solution of 0.1 weight percent of trimesoyl chloride in normal hexane;
(2) Pouring the organic phase solution prepared in the step (1) on one side surface of the PE support material, soaking for 5min, and removing redundant solution;
(3) The water phase solution prepared in the step (1) is cast on the other side surface of the support layer material obtained in the step (2), and after polymerization for 10min through a back diffusion interface, redundant solution is removed;
(4) And (3) carrying out heat treatment at 60 ℃ for 15min to obtain the polyolefin polyamide composite membrane prepared by the heterolateral transmembrane back-diffusion interfacial polymerization.
The polyethylene-polyamide composite membrane prepared in the embodiment is put into a nanofiltration membrane performance evaluation device, and experimental conditions are as follows: 0.6Mpa, 0.5h of prepressing and 1000ppm of sodium sulfate concentration. Experimental results: water flux: 85.8L/(m 2. H), retention: 96.4%.
Example 9
(1) Preparing an aqueous solution of 0.08 weight percent of anhydrous piperazine and 0.1 weight percent of cetyltrimethylammonium bromide (CTAB) as aqueous phase solution, and preparing an organic phase solution of 0.1 weight percent of trimesic chloride in normal hexane;
(2) Pouring the organic phase solution prepared in the step (1) on one side surface of the PE support material, soaking for 5min, and removing redundant solution;
(3) The water phase solution prepared in the step (1) is cast on the other side surface of the support layer material obtained in the step (2), and after polymerization for 10min through a back diffusion interface, redundant solution is removed;
(4) And (3) carrying out heat treatment at 60 ℃ for 15min to obtain the polyolefin polyamide composite membrane prepared by the heterolateral transmembrane back-diffusion interfacial polymerization.
The polyethylene-polyamide composite membrane prepared in the embodiment is put into a nanofiltration membrane performance evaluation device, and experimental conditions are as follows: 0.6Mpa, 0.5h of prepressing and 1000ppm of sodium sulfate concentration. Experimental results: water flux: 53.76L/(m 2. H), retention: 96.6%.
Example 10
(1) Preparing an aqueous solution of 0.08 weight percent of anhydrous piperazine and 0.15 weight percent of cetyltrimethylammonium bromide (CTAB) as aqueous phase solution, and preparing an organic phase solution of 0.1 weight percent of trimesic chloride in normal hexane;
(2) Pouring the organic phase solution prepared in the step (1) on one side surface of the PE support material, soaking for 5min, and removing redundant solution;
(3) The water phase solution prepared in the step (1) is cast on the other side surface of the support layer material obtained in the step (2), and after polymerization for 10min through a back diffusion interface, redundant solution is removed;
(4) And (3) carrying out heat treatment at 60 ℃ for 15min to obtain the polyolefin polyamide composite membrane prepared by the heterolateral transmembrane back-diffusion interfacial polymerization.
The polyethylene-polyamide composite membrane prepared in the embodiment is put into a nanofiltration permeable membrane performance evaluation device, and experimental conditions are as follows: 0.6Mpa, 0.5h of prepressing and 1000ppm of sodium sulfate concentration. Experimental results: water flux: 41.1L/(m 2. H), retention: 97.1%.
Comparative example 1: the same side (forward) interfacial polymerization was employed as shown in fig. 4.
(1) Preparing 2wt% of m-phenylenediamine, preparing 0.1wt% of aqueous solution of hexadecyl trimethyl ammonium p-toluenesulfonate as an aqueous phase solution, and preparing 0.1wt% of normal hexane solution of trimesoyl chloride as an organic phase solution for later use;
(2) Pouring the aqueous phase solution prepared in the step (1) on the surface of the PE support material, soaking for 12min, and removing redundant solution;
(3) The organic phase solution prepared in the step (1) is cast on the same side surface of the support layer material obtained in the step (2), and after interfacial polymerization for 2min, redundant solution is removed;
(4) And (3) carrying out heat treatment at 60 ℃ for 15min to obtain the polyethylene-polyamide composite membrane prepared by ipsilateral (forward) interfacial polymerization.
The polyethylene-polyamide composite membrane prepared in the comparative example is put into a forward osmosis membrane performance evaluation device, then 1mol/L sodium chloride aqueous solution is taken as a drawing liquid, deionized water is taken as a raw material liquid, and the measured membrane flux is 9.74L/(m 2. H), and the salt back-mixing flux is 0.0328 mol/(m 2. H).
Comparative example 2: when reverse phase interfacial polymerization is employed, it is shown in FIG. 3.
(1) Preparing an aqueous solution of 0.08 weight percent of anhydrous piperazine and 0.075 weight percent of cetyltrimethylammonium bromide (CTAB) as an aqueous phase solution, and preparing an organic phase solution of 0.1 weight percent of trimesoyl chloride in normal hexane;
(2) Pouring the organic phase solution prepared in the step (1) on one side surface of the PE support material, soaking for 5min, and removing redundant solution;
(3) The aqueous phase solution prepared in the step (1) is cast on the same side surface of the support layer material obtained in the step (2), and after interfacial polymerization for 10min, redundant solution is removed;
(4) And (3) carrying out heat treatment at 60 ℃ for 15min to obtain the polyolefin-polyamide composite membrane prepared by reverse phase interfacial polymerization.
The polyethylene-polyamide composite membrane prepared in the comparative example is put into a nanofiltration membrane performance evaluation device, and experimental conditions are as follows: 0.6Mpa, 0.5h of prepressing and 1000ppm of sodium sulfate concentration. Experimental results: water flux: 66.96L/(m 2. H), retention: 94.7%.
Fig. 5 is an SEM image of a polyethylene blank film. In fig. 6, fig. a and b are respectively surface scanning electron microscope images of the different-side transmembrane back-diffusion interfacial polymeric forward osmosis membrane prepared in example 3 (a is a water side back surface and b is an oil side front surface), and fig. c and d are respectively surface scanning electron microscope images of the same-side interfacial polymeric forward osmosis membrane prepared in comparative example 1 (c is a PE back surface and d is a PA front surface). The back side of both films fig. 6a and 6c form a similar PE/PA porous structure, but their front side structure diagrams 6b and 6d are quite different. FIG. 6b shows the oil phase front of the forward osmosis membrane prepared by the method of example 3 of the present invention, only part of the PA is covered, while the front surface of FIG. 6d of comparative example 1 is significantly covered by a layer of closely spaced bladed PA.
As shown in fig. 7, the cross-sectional N element profiles of the polyethylene-polyamide composite membrane prepared by the ipsilateral trans-base membrane back diffusion interfacial polymerization of example 3 and the ipsilateral interfacial polymerization of comparative example 1 were compared from left to right. It can be seen from the surface that polyamide separation layers are formed distributed in the PE-based membrane. As can be seen from fig. 7, the structural characteristics of the sections are significantly different, the homolateral interfacial polymerization composite membrane mainly forms a dense polyamide layer on the top and front sides, and the heterolateral back diffusion interfacial polymerization composite membrane forms a polyamide layer inside the sections.
In fig. 8, fig. e and f are respectively a scanning electron microscope image of the oil-phase-before-water-phase different-side transmembrane back-diffusion interfacial polymerization composite membrane prepared in example 8 (e is the back oil side and f is the front water side), and fig. g and h are respectively the same-side reverse-phase interfacial polymerization composite membrane prepared in comparative example 2 (g is the back bottom layer and h is the front PA side). The back side of both films fig. 8e and 8g form a similar PE/PA porous structure, but their front side structures fig. 8f and 8h are quite different. FIG. 8f shows the aqueous front of a nanofiltration membrane prepared according to the method of example 8 of the present invention, while partially PA coated, but significantly inside; whereas comparative example 2 the dense PA layer covering the front side of fig. 8 is more superficial.
Fig. 9 shows the distribution of N element in the cross section of the hetero-side transmembrane back-diffusion interfacial polymerization membrane prepared in example 8 and the reverse-phase interfacial polymerization nanofiltration membrane prepared in comparative example 2, from left to right, respectively, and it can be seen that the polyamide in the composite membrane prepared by hetero-side transmembrane back-diffusion interfacial polymerization is distributed in the polyolefin base membrane, and the polyamide layer obtained by the same-side reverse-phase interfacial polymerization is closer to the upper surface, and the distribution characteristics of the cross sections are completely different.
The surface water contact angles of the examples and comparative examples are compared in fig. 10. The reverse sides of comparative examples 1 and 2 have very strong hydrophobic properties, and the water contact angle is as high as that of the PE film and is between 84 and 88 degrees. The oil phase surfaces of example 8 and example 3 are relatively hydrophilic, and their water contact angles are between 51 and 58 degrees with the polyamide surface of comparative example 1. The contact angles of the aqueous phase surfaces of example 8 and example 3 were 23.5 degrees and 70.9 degrees, respectively, although they were different, they were lower than those of the PE base film, and they had good hydrophilicity.
TABLE 1 Forward osmosis Performance differences (membrane organic phase side towards draw solution) for different preparation methods
TABLE 2 nanofiltration Performance differences (membrane aqueous phase side facing into water) for different preparation methods
As can be seen from the data in Table 1, the Jw of the polyethylene-polyamide composite forward osmosis membrane prepared by the ipsilateral trans-base membrane back diffusion interfacial polymerization is increased from 9.74L/(m 2. H) to 24.73L/(m 2. H) compared with the ipsilateral interfacial polymerization, and the Js is not greatly changed, so that the selectivity of the forward osmosis performance is effectively improved.
As can be seen from the data in table 2, the ipsilateral transmembrane back-diffusion interfacial polymerization has a higher pure water flux and higher sodium sulfate rejection than the nanofiltration membrane of the reverse phase interfacial polymerization.
As can be seen from fig. 11, as the concentration of the surfactant cetyl trimethyl para-benzenesulfonic acid amine (CTAT) increases, jw of the ipsilateral transmembrane back-diffusion interfacial polymerization process to prepare the polyethylene-polyamide composite forward osmosis membrane increases and decreases, while Js increases and stabilizes, reaching the optimum selectivity at 0.1 wt%; at CTAT concentrations of 0.1 to 0.15 wt.%, the thickness of the polyamide increases, resulting in a decrease in water flux.
FIG. 12 shows the effect of different surfactant cetyl trimethylammonium bromide (CTAB) concentrations on the performance of the ipsilateral transmembrane back-diffusion interfacial polymerization to prepare composite nanofiltration membranes of example 8. When the CTAB concentration is increased from 0.025wt% to 0.075wt%, the flux of the sodium sulfate solution is increased from 7.14 L.m -2·h-1 to 85.8 L.m -2·h-1, and the rejection rate of sodium sulfate is reduced from 97.5% to 96.4%, because the increase of CTAB concentration increases the hydrophilicity of the membrane, so that the flux of the membrane is also increased. When the cetyl trimethylammonium bromide (CTAB) concentration was increased from 0.075wt% to 0.125wt%, the sodium sulfate flux was reduced from 85.8L.m-2.h-1 to 41.1L.m -2·h-1, and the sodium sulfate rejection increased from 96.4% to 97.1%, because the piperazine was allowed to react well with TMC as the surfactant CTAB concentration was increased, the polyamide layer thickened, and the sodium sulfate rejection increased accordingly.
According to the polyethylene-polyamide composite membrane prepared by the reverse diffusion interfacial polymerization of the different-side transmembrane, different monomers are applied to two sides of the supporting layer, polyamide is formed inside by utilizing the permeation and diffusion capacities of the different-side transmembrane, and high water flux and low salt reverse mixing flux are ensured. At the same time, has high pressure resistance, high salt cutting rate and high mechanical strength, and can be used for emergency water bags food concentration, green energy, sea water desalination, hard water softening, industrial wastewater and the like.
The above embodiments are not intended to limit the present invention, and the present invention is not limited to the above examples, but is also intended to be limited to the following claims.

Claims (10)

1. A polyolefin-based polyamide composite membrane prepared by the reverse diffusion interfacial polymerization of an isosceles transmembrane is characterized in that: the composite film includes: a porous polyolefin support layer, a polyamide composite layer obtained by the reverse diffusion interfacial polymerization of an opposite-side transmembrane inside the porous polyolefin support layer, and a surfactant.
2. The polyolefin-based polyamide composite membrane prepared by the ipsi-base membrane back-diffusion interfacial polymerization according to claim 1, wherein: the porous polyolefin supporting layer is composed of one or more of polyethylene, polypropylene, polyvinylidene fluoride and polytetrafluoroethylene polymers.
3. The polyolefin-based polyamide composite membrane prepared by the ipsi-base membrane back-diffusion interfacial polymerization according to claim 1, wherein: the surfactant is one or more of Tween 80, sodium dodecyl sulfate, cetyltrimethylammonium bromide, cetyltrimethyl-p-toluenesulfonic acid amine or derivatives thereof.
4. A method for producing a polyolefin-based polyamide composite membrane produced by the isosceles transmembrane back-diffusion interfacial polymerization according to any one of claims 1 to 3, characterized in that: the method comprises the following steps:
S1, preparing aqueous solution of polyamine as aqueous phase solution, adding surfactant into the aqueous phase solution, and preparing alkane solution of aromatic acyl chloride as organic phase solution for later use;
Step S2, the water phase solution or the organic phase solution prepared in the step S1 is cast on the surface of any side of the porous polyolefin support material, and after soaking for a certain time, redundant solution is removed;
Step S3, the organic phase solution or the aqueous phase solution prepared in the step S1 is cast on the surface of the other side of the porous polyolefin support material obtained in the step S2, and after a period of time of polymerization through a back diffusion interface, the redundant solution is removed;
and S4, performing heat treatment at a certain temperature to obtain the polyolefin-based polyamide composite membrane prepared by the reverse diffusion interfacial polymerization of the heterolateral transmembrane.
5. The method for producing a polyolefin-based polyamide composite membrane produced by the ipsi-back diffusion interfacial polymerization according to claim 4, wherein: in the step S1, the polyamine is any one or a mixture of more of m-phenylenediamine, ethylenediamine, piperazine, polyethyleneimine or derivatives thereof.
6. The method for producing a polyolefin-based polyamide composite membrane produced by the ipsi-back diffusion interfacial polymerization according to claim 4, wherein: in the step S1, the aromatic acyl chloride is one or a mixture of more of trimesoyl chloride, naphthalene ring triacyl chloride, other aromatic polybasic sulfonyl chloride or derivatives thereof.
7. The method for producing a polyolefin-based polyamide composite membrane produced by the ipsi-back diffusion interfacial polymerization according to claim 4, wherein: in the step S1, the alkane solvent is one or more solvents selected from n-hexane, n-pentane, isododecane and isohexadecane.
8. The method for producing a polyolefin-based polyamide composite membrane produced by the ipsi-back diffusion interfacial polymerization according to claim 4, wherein: in the step S1, the concentration of the aqueous phase solution is 0.01-5 wt%, the concentration of the surfactant in the aqueous phase solution is 0.001-1 wt%, and the concentration of the organic phase solution is 0.001-1 wt%.
9. The method for producing a polyolefin-based polyamide composite membrane produced by the ipsi-back diffusion interfacial polymerization according to claim 4, wherein: in the step S2, the infiltration time of the water phase is 1-15 min, and the contact time of the organic phase in the step S3 is 1-8 min.
10. The method for producing a polyolefin-based polyamide composite membrane produced by the ipsi-back diffusion interfacial polymerization according to claim 4, wherein: in the step S4, the drying temperature is 30-80 ℃ and the drying time is 5-20 min.
CN202410073910.6A 2024-01-18 2024-01-18 Polyolefin-based polyamide composite membrane prepared by iso-side transmembrane anti-diffusion interfacial polymerization and preparation method thereof Pending CN117959950A (en)

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Publication number Priority date Publication date Assignee Title
CN119215680A (en) * 2024-10-29 2024-12-31 福安新友环保科技有限公司 Polyamide composite nanofiltration membrane prepared by reverse diffusion interfacial polymerization across polyolefin-based membrane and preparation method thereof

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN119215680A (en) * 2024-10-29 2024-12-31 福安新友环保科技有限公司 Polyamide composite nanofiltration membrane prepared by reverse diffusion interfacial polymerization across polyolefin-based membrane and preparation method thereof

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