Composite membrane and method for producing same

Abstract

The present invention relates to a method for making a composite membrane, comprising impregnating a surface of a porous membrane substrate with an aqueous suspension comprising a mixture of at least one polyamine and at least one phospholipid, and contacting the impregnated surface with an organic phase containing a monomer, thereby depositing a polyamide layer on the impregnated surface. The present invention also relates to a composite membrane comprising at least one porous membrane substrate having nano- or micro-sized pores and at least one polyamide layer disposed on the surface of the porous membrane substrate, the polyamide layer comprising at least one phospholipid dispersed therein, and the polyamide layer being an interfacial polymerization product.

Description

[Technical Field]

[0001] [Priority Claim] This application claims priority to Singapore Patent Application No. 10202003091Q, filed April 2, 2020, which is incorporated herein by reference in its entirety for all purposes.

[0002] The present invention relates to membranes for water filtration. In particular, the present invention relates to composite membranes and methods for making the same. [Background technology]

[0003] Membrane technology is an essential component of various industrial and commercial processes, including, but not limited to, water recovery, seawater desalination, water purification, food processing, manufacturing processes in the pharmaceutical industry, and medical applications. An important application of membrane technology is the production of purified or potable water. The provision of drinking water typically involves the use of reverse osmosis (RO) and / or nanofiltration (NF) membranes. Particularly in the field of water purification / treatment, the use of highly permeable membranes is generally preferred due to a number of benefits. For example, the use of highly permeable membranes can result in reduced capital costs (e.g., because a smaller membrane area is required for a desired level of permeate output), which can result in other advantages, such as space savings due to a smaller membrane device footprint, or reduced energy consumption due to membranes being able to operate at lower pressures.

[0004] A common challenge faced by RO and NF membranes is the requirement to balance the need for increased permeability of water molecules while maintaining acceptable rejection of solutes and / or ions.

[0005] To address this challenge, most thin-film composite (TFC) RO and / or NF membranes have a selective layer deposited on the surface of the membrane substrate to enhance the membrane's water permeability. Such a selective layer may include nanoparticles / water channel compounds. In one example, a biomimetic TFC membrane contains protein-based water-selective channels, such as aquaporins (AQPs). The presence of aquaporins has been observed to increase the membrane's hydrophilicity while maintaining a stable salt rejection level. However, significant obstacles exist for the scale-up or commercialization of such membranes. For example, the production of biological proteins is a challenging endeavor, involving protein expression by a host organism, a process that is difficult to control. Subsequently, a series of protein purification steps are required to obtain the desired protein before incorporation into the membrane, which can lead to relatively high production costs compared to other types of RO / FO membranes.

[0006] Nanocomposite membranes have also been widely studied on a laboratory scale for use in the water treatment industry. Such membranes typically involve the incorporation of nanomaterials into the membrane to alter its physicochemical properties, such as hydrophilicity, porosity, charge density, durability, etc. For example, carbon nanotubes have been embedded in polymeric membranes in the preparation of mixed matrix membranes used in water purification processes. However, such nanocomposite membranes also require complex fabrication processes and face challenges during operation, which can hinder their use. Typical problems encountered during the fabrication or operation of such nanocomposite membranes include, for example, poor dispersion of the nanomaterials in the polymer matrix, aggregation of nanoparticles causing defects on the membrane surface, and the potential for leakage of nanomaterials resulting in toxicity and / or contamination of treated water. Summary of the Invention [Problem to be solved by the invention]

[0007] Therefore, there is a need to provide an alternative method for preparing membranes intended for use in water treatment or purification that ameliorates or avoids the above-mentioned problems.It is yet another object of the present disclosure to provide novel membranes prepared by the methods disclosed herein that are substantially free of biological proteins, such as aquaporins. [Means for solving the problem]

[0008] In one aspect of the present disclosure, there is provided a method for preparing a composite membrane comprising: a) impregnating a surface of a porous membrane substrate with an aqueous suspension comprising a mixture of at least one polyamine and at least one phospholipid; and b) contacting the impregnated surface with an organic phase containing a monomer comprising at least one crosslinking group, thereby depositing a polyamide layer on the impregnated surface, wherein the polyamide layer comprises a phospholipid dispersed therein, and wherein the polyamide layer is an interfacial polymerization product.

[0009] In another aspect of the present invention, there is provided a composite membrane comprising at least one porous membrane substrate having nano-sized or micro-sized pores and at least one polyamide layer disposed on a surface of the porous membrane substrate, wherein the polyamide layer comprises a phospholipid dispersed therein, and the polyamide layer is an interfacial polymerization product.

[0010] Advantageously, it has been observed that the incorporation of phospholipids into the polyamide layer results in an unexpected and substantial improvement in membrane selectivity without impairing the membrane's ability to remove solutes and impurities (e.g., salts) from the water being treated. In particular, it has been found that membranes prepared in accordance with the present disclosure can substantially increase the membrane's permeability to water while maintaining a salt (e.g., NaCl) rejection rate of at least 90% or greater, or preferably about 95% or greater, at an applied pressure of about 2 bar.

[0011] The improved membrane permeability can potentially be attributed to the unique topography of the polyamide selective layer and the presence of lipids. In one embodiment, the formation of leaf-like structures or leaf-like features was observed on a polyamide layer formed from an aromatic polyamine and an aromatic crosslinker in the presence of phospholipids. These leaf-like structures can be characterized as blade-like protrusions extending upward from the bottom surface of the polyamide layer. The bottom surface refers to the surface of the polyamide layer that is attached to the underlying membrane substrate and may be composed of a different polymer, such as polyethersulfone. These protruding leaf-like structures can typically be 200 nm to 4000 nm in height (calculated from the bottom surface of the polyamide layer). It is hypothesized that the presence of these surface structures on the wholly aromatic polyamide layer increases the surface area in contact with water molecules, thereby facilitating water transport through the membrane.

[0012] Furthermore, polyamide layers formed in the presence of phospholipids can also form large interstitial spaces that help focus the transport of water molecules toward and across the underlying membrane substrate. Such an effect can be observed for semi-aromatic polyamide layers less than 100 nm in height formed using aliphatic polyamides and aromatic monomers with at least one crosslinking group in the presence of phospholipids.

[0013] In some embodiments of the present invention, it has been demonstrated that membranes comprising a polyamide layer with embedded phospholipids can achieve water permeability six to eight times higher than comparable membranes lacking the presence of lipids in the selective polyamide layer. Even more advantageously, membranes according to the present invention have been found to be relatively easy and inexpensive to manufacture, while achieving similar permeability / removal performance when compared to currently available aquaporin-containing membranes.

[0014] definition As used herein, the following words and terms shall have the following meanings:

[0015] The term "crosslinker" as used herein should be broadly interpreted to refer to any compound or monomer having functional groups capable of crosslinking. This includes monomers that can be used to link polymer chains via covalent bonds to form a polymer network. The crosslinker may contain reactive functional groups that form covalent bonds to link one or more monomers. The crosslinker itself may be incorporated into the polymer network. In the context of the present invention, a monomer having functional groups capable of crosslinking or a monomer having at least one crosslinking group may be referred to as a "crosslinker."

[0016] The term "monomer," as used herein, may refer to a compound that can chemically react with other molecules, which may or may not be of the same type, to form larger molecules. Monomers may contain functional groups that are capable of forming covalent bonds and reacting with other molecules.

[0017] As used herein, the term "polymer" may refer to a compound that includes multiple repeating units of a monomer. A polymer may also include an infinite number of repeating units of a monomer.

[0018] As used herein, the term "aliphatic" may refer to non-aromatic hydrocarbon compounds, groups, or radicals. These may include saturated or unsaturated hydrocarbons with single, double, or triple carbon-carbon bonds. Aliphatic compounds may also include straight-chain, branched, or cyclic compounds.

[0019] As used herein, the term "acyl" can refer to a radical of the general formula -C(O)R, where R is an alkyl, cycloalkyl, aryl, heterocycloalkyl, or heteroaryl group. Accordingly, the term "acyl halide" refers to a compound having the general formula RC(O)X, where R is an alkyl, cycloalkyl, aryl, heterocycloalkyl, or heteroaryl group, and X is a halide atom, such as F, Cl, Br, or I.

[0020] As used herein, the term "sulfonyl" can refer to the -SO- biradical. Thus, the term "halogenated sulfonyl" can refer to a functional group of formula -SOX, where X is a halide atom, such as F, Cl, Br, or I.

[0021] The term "semi-aromatic" as used herein to describe a polyamide layer, i.e., a "semi-aromatic polyamide layer," can refer to a polyamide layer formed using at least one aromatic monomer and at least one non-aromatic monomer. For example, a semi-aromatic polyamide layer can be formed using an aliphatic polyamine and an aromatic crosslinker, or an aromatic polyamine and an aliphatic crosslinker.

[0022] The term "fully aromatic" as used herein to describe a polyamide layer, i.e., a "fully aromatic polyamide layer," can refer to a polyamide network formed from aromatic monomers. For example, a fully aromatic polyamide layer can be formed from an aromatic crosslinker and an aromatic polyamine.

[0023] As used herein, the terms "apparent height," "height," "thickness," or grammatical variations thereof, when used to describe a polyamide layer, may refer to the distance between the bottom surface of the polyamide layer and the tip of any structure or feature disposed thereon.

[0024] As used herein, the term "alkyl group" specifically includes, but is not limited to, monovalent ("alkyl") and divalent ("alkylene") straight- or branched-chain saturated aliphatic groups having at least one carbon atom, or C1-50 alkyl, C1-40 alkyl, C1-30 alkyl, or any number of carbon atoms within these ranges. For example, C1-12 alkyl includes methyl, ethyl, 1-propyl, isopropyl, 1-butyl, 2-butyl, isobutyl, tert-butyl, amyl, 1,2-dimethylpropyl, 1,1-dimethylpropyl, pentyl, isopentyl, hexyl, 4-methylpentyl, 1-methylpentyl, 2-methylpentyl, 3-methylpentyl, 2,2-dimethylbutyl, 3,3-dimethylbutyl, 1,2-dimethylbutyl, 1,3-dimethylbutyl, 1,2,2-trimethylpropyl, 1,1,2- Examples include, but are not limited to, trimethylpropyl, 2-ethylpentyl, 3-ethylpentyl, heptyl, 1-methylhexyl, 2,2-dimethylpentyl, 3,3-dimethylpentyl, 4,4-dimethylpentyl, 1,2-dimethylpentyl, 1,3-dimethylpentyl, 1,4-dimethylpentyl, 1,2,3-trimethylbutyl, 1,1,2-trimethylbutyl, 1,1,3-trimethylbutyl, 5-methylheptyl, 1-methylheptyl, octyl, nonyl, decyl, dodecyl, etc. The group may be a terminal group or a bridging group.

[0025] "Alkenyl" as a group or part of a group may refer to an aliphatic hydrocarbon group that contains at least one carbon-carbon double bond and may be straight-chained or branched, including, but not limited to, at least 2 carbon atoms, 2 to 50 carbon atoms, 2 to 25 carbon atoms, 12 to 24 carbon atoms, or any number of carbons within these ranges in the linear chain. The group may contain multiple double bonds in the linear chain, each of which, where applicable, is independently oriented E, Z, cis, or trans. Exemplary alkenyl groups include, but are not limited to, ethenyl, propenyl, butenyl, pentenyl, hexenyl, heptenyl, octenyl, and nonenyl. The group may be a terminal group or a bridging group.

[0026] As used herein, the term "aromatic group," or variations thereof, such as "aryl" or "arylene," can refer to monovalent ("aryl") and divalent ("arylene") single, polynuclear, conjugated, and fused residues of aromatic hydrocarbons having 6 to 10 carbon atoms. Examples of such groups include phenyl, biphenyl, naphthyl, phenanthrenyl, and the like.

[0027] The term "substantially" does not exclude "completely", for example, a composition that is "substantially free" of Y may be completely free of Y. If desired, the term "substantially" may be excluded from the definition of the present invention.

[0028] Unless otherwise indicated, the terms "comprising" and "comprise," and grammatical variations thereof, are intended to denote "open" or "inclusive" language that not only includes the recited elements, but also permits the inclusion of additional, unrecited elements.

[0029] The term "about" as used herein in connection with the concentration of a formulation component typically means ±5% of the stated value, more typically ±4% of the stated value, more typically ±3% of the stated value, more typically ±2% of the stated value, even more typically ±1% of the stated value, and even more typically ±0.5% of the stated value.

[0030] Throughout this disclosure, certain embodiments may be disclosed in a range format. It is understood that the description in range format is merely for convenience and brevity and should not be construed as an inflexible limit on the disclosed ranges. Accordingly, the description of a range should be construed as including all specifically disclosed subranges and individual numerical values ​​within that range. For example, a description of a range of 1 to 6 should be construed as including specifically disclosed subranges such as 1 to 3, 1 to 4, 1 to 5, 2 to 4, 2 to 6, 3 to 6, etc., and individual numerical values ​​within that range, e.g., 1, 2, 3, 4, 5, and 6. This applies regardless of the breadth of the range.

[0031] Certain embodiments may be broadly and generically described herein. Each of the narrower species and subgeneric groupings falling within the generic disclosure also forms part of this disclosure. This includes generic descriptions of embodiments with a condition or negative limitation excluding any subject matter from the genus, regardless of whether the excluded matter is specifically recited herein.

[0032] The accompanying drawings, in which like reference numerals refer to identical or functionally similar elements throughout the different views, and which, together with the following detailed description, are incorporated in and form a part of this specification, illustrate various embodiments and serve to explain various principles and advantages in accordance with the present embodiments. [Brief explanation of the drawings]

[0033] [Figure 1] 1 is a schematic diagram of an exemplary crossflow membrane filtration system including a membrane module / cell, a pump, a feed line L1, a permeate line L2, a retentate line L3, and pressure gauges P1, P2, and P3. [Figure 2a]Scanning electron micrographs comparing the surface of a control membrane with a wholly aromatic polyamide layer containing no phospholipids (left) and the surface of a composite membrane described herein formed with m-phenylenediamine (MPD) and 1,3,5-benzene-tricarbonyl trichloride (TMC) and having a wholly aromatic polyamide layer with at least one phospholipid, 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC), dispersed therein. [Figure 2b] 1 shows scanning electron micrographs of the cross sections of a wholly aromatic polyamide layer formed without using DOPC, and a wholly aromatic polyamide layer formed using MPD and TMC and containing dispersed DOPC, a phospholipid. [Figure 3a] 1 is a photomicrograph showing the surface tomography of a control membrane with a polyamide layer formed without DOPC, obtained using atomic force microscopy (AFM). [Figure 3b] 1 is an AFM micrograph showing the surface tomography of a membrane comprising a polyamide layer with DOPC dispersed therein. [Figure 4] FIG. 1 shows an exemplary 4-inch membrane module containing 3200 fibers. [Figure 5a] 1 is a graphical representation of the performance of Membrane Module 1 in filtering NEWater reverse osmosis feedwater. Membrane Module 1 is an exemplary membrane module comprising a composite membrane described herein prepared with DOPC and having an effective membrane area of ​​300 cm. As shown on the graph, Jv is a measure of water flux (represented by ○), P inlet is the applied pressure at the inlet (represented by △), and R is the conductivity rejection (represented by □). [Figure 5b] 1 is a graphical representation of the performance of a second membrane module (Membrane Module 2) in filtering NEWater reverse osmosis feedwater. Membrane Module 2 is an exemplary membrane module comprising a composite membrane described herein prepared with DOPC and having an effective membrane area of ​​70 cm. DETAILED DESCRIPTION OF THE INVENTION

[0034] Those skilled in the art will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some elements in illustrations, block diagrams, or flowcharts may be exaggerated relative to other elements to help to improve understanding of the embodiments.

[0035] The following detailed description is merely exemplary in nature and is not intended to limit the invention or the application and uses of the invention. Furthermore, there is no intention to be bound by the preceding background of the invention or any theory presented in the following detailed description.

[0036] In this specification, a) impregnating the surface of a porous membrane substrate with an aqueous suspension comprising a mixture of at least one polyamine and at least one phospholipid; b) contacting the impregnated surface with an organic phase containing a monomer comprising at least one crosslinking group (i.e., a monomer comprising a functional group capable of crosslinking), thereby depositing a polyamide layer on the impregnated surface; Including, A method for preparing a composite membrane is provided, wherein the polyamide layer comprises at least one phospholipid dispersed therein, and the polyamide layer is an interfacial polymerization product.

[0037] The step of impregnating the surface of the porous membrane substrate can be carried out by exposing the surface of the porous membrane substrate to an aqueous suspension containing a mixture of at least one polyamine and at least one phospholipid.The aqueous suspension can be brought into contact with the surface or lumen surface of the porous membrane substrate, and the surface of the porous membrane substrate can be impregnated.A pressure gradient can be optionally applied during the contacting step.Alternatively, the aqueous suspension can be sprayed or poured onto the surface of the membrane.The membrane can also be immersed in the aqueous suspension, and the surface of the porous membrane substrate can be impregnated.

[0038] In an embodiment, when a hollow fiber composite membrane is prepared, the aqueous suspension is flowed or passed through the lumen of the hollow fiber composite membrane to impregnate the surface of the lumen. When a flat membrane is prepared by the disclosed method, the aqueous suspension is poured onto the surface of the flat membrane. Alternatively, the flat membrane may be immersed in the aqueous suspension and the aqueous suspension may be sprayed onto the surface of the flat membrane.

[0039] The porous membrane substrate used in the method described herein can contain nano-sized or micro-sized pores.The porous membrane substrate can be made of organic or inorganic materials, which can be synthetic or naturally occurring.Inorganic porous membranes, including zeolites and ceramic membranes, such as aluminum oxide, silicon carbide, titanium dioxide, and zirconium dioxide, can also be used as substrates in the method described herein.

[0040] In embodiments, the membrane substrate is preferably a synthetic organic porous substrate. Such membranes can be prepared using spinning or casting methods known in the art. During the preparation of the porous membrane substrate, additives can be used at concentrations sufficient to adjust the porosity and / or hydrophilicity of the final membrane substrate. Non-limiting examples of membrane materials that can be used herein include polyethersulfone (PES), polyetherimide (PEI), polysulfone (PSF), polyacrylonitrile (PAN), polyvinylidene difluoride (PVDF), poly(tetrafluoroethylene) (PTFE), polyethylene (PE), polypropylene (PP), polyimide (PI), or copolymers thereof. The porous membrane substrate can preferably comprise polyethersulfone (PES), polyetherimide (PEI), polysulfone (PSF), polyacrylonitrile (PAN), polyvinylidene difluoride (PVDF), or copolymers thereof. In embodiments, the porous membrane substrate is made from polyetherimide (PEI) or polyethersulfone (PES).

[0041] The surface of the porous membrane substrate can be impregnated with an aqueous suspension comprising at least one polyamine and at least one phospholipid. The aqueous suspension can be substantially free of transmembrane proteins or analogs thereof. In particular, the aqueous suspension can be substantially free of aquaporins, and the resulting polyamide layer deposited on the surface of the porous membrane can also be substantially free of aquaporins.

[0042] Advantageously, composite membranes prepared according to the methods disclosed herein exhibit good water permeability and increased solute rejection, even in the absence of transmembrane proteins such as aquaporins. In embodiments, the membranes exhibit a permeability of 5000 cm 2 or 32,000 cm 2 For an exemplary membrane module with an effective area of ​​1000 mbar, a water permeability of up to approximately 6 LMH / bar and a sodium chloride rejection rate of approximately 94% to 96% were observed at a transmembrane pressure difference of 2 bar. The performance of the composite membranes disclosed herein is comparable to aquaporin-based membranes with similar effective areas. This is likely due to the presence of phospholipids, which promote interfacial polymerization and allow for the deposition of polyamide layers with increased effective membrane area or increased interfacial distance between the polyamide layer and the substrate surface. This also increases the membrane's water permeability, independent of the quality of biomolecules such as aquaporins. Therefore, the fabrication and quality of composite membranes can be adjusted and controlled during industrial production.

[0043] The polyamine may be added at a concentration of about 0.001% to about 10% by weight based on the weight of the aqueous suspension. The aqueous suspension may contain the polyamine at a concentration of about 0.001% to about 10% by weight, or about 0.005% to about 10% by weight, or about 0.01% to about 10% by weight, or about 0.05% to about 10% by weight, or about 0.1% to about 10% by weight, or about 0.1% to about 9% by weight, or about 0.1% to about 8% by weight, or about 0.1% to about 7% by weight, or about 0.1% to about 6% by weight, or about 0.1% to about 5% by weight, or about 0.1% to about 4.5% by weight, or about 0.1% to about 4% by weight, or about 0.15% to about 4% by weight, or about 0.2% to about 4% by weight, or about 0.25% to about 3.5% by weight, or preferably about 0.5% to about 3% by weight, based on the weight of the aqueous suspension. In an embodiment, the polyamine is provided at a concentration of about 1.2% by weight based on the weight of the aqueous suspension.

[0044] The polyamine may be a water-soluble polyamine. The polyamine may contain at least two amine groups. The polyamine may contain 2 to 100 amine groups, or 2 to 90 amine groups, or 2 to 80 amine groups, or 2 to 70 amine groups, or 2 to 60 amine groups, or 2 to 50 amine groups, or 2 to 40 amine groups, or 2 to 30 amine groups, or 2 to 20 amine groups, or 2 to 18 amine groups, or 2 to 16 amine groups, or 2 to 14 amine groups, or 2 to 12 amine groups, or 2 to 10 amine groups, or 2 to 9 amine groups, or 2 to 8 amine groups, or 2 to 7 amine groups, or 2 to 6 amine groups, or 2 to 5 amine groups, or preferably 2 to 4 amine groups. In an embodiment, the polyamine contains two amine groups.

[0045] The amine groups in the polyamine can be independently primary amine groups or secondary amine groups.In embodiments, the polyamine can be a monomer containing at least two amine groups, and the polyamine is a monomer containing at least two amine groups, and the amine groups are independently primary amine groups or secondary amine groups.For example, the polyamine used in the impregnation step can contain two primary amine groups, two secondary amine groups, or one primary amine group and one secondary amine group, i.e., a mixture of primary amine groups and secondary amine groups.In embodiments, the polyamine contains two primary amine groups.

[0046] The polyamine may contain at least two carbon atoms. For example, the polyamine may contain 2 to 500 carbon atoms, or 2 to 450 carbon atoms, or 2 to 400 carbon atoms, or 2 to 350 carbon atoms, or 2 to 300 carbon atoms, or 2 to 250 carbon atoms, or 2 to 200 carbon atoms, or 2 to 180 carbon atoms, or 2 to 160 carbon atoms, or 2 to 140 carbon atoms, or 2 to 120 carbon atoms, or 2 to 100 carbon atoms, or 2 to 90 carbon atoms, or 2 to 80 carbon atoms, or 2 to 70 carbon atoms, or 2 to 60 carbon atoms, or 2 to 50 carbon atoms, or 2 to 40 carbon atoms, or 2 to 30 carbon atoms, or 2 to 20 carbon atoms, or 2 to 10 carbon atoms, preferably 4 to 10 carbon atoms. In some embodiments, the polyamine contains 6 carbon atoms. In other embodiments, the polyamine comprises 4 carbon atoms.

[0047] The polyamine may be an aliphatic, aromatic, or heterocyclic polyamine. The aliphatic polyamine that can be used in the method disclosed herein may contain an alkyl group, an alkenyl group, a cycloalkyl group, or an alkynyl group. The polyamine may preferably be an aromatic polyamine or a heterocyclic polyamine. As demonstrated in the examples, the polymerization of an aromatic polyamine with an aromatic crosslinker advantageously results in the formation of the leaf-like structure disclosed herein, thereby improving the water permeability of the membrane.

[0048] Polyamines include m-phenylenediamine (MPD), m-phenylenediamine-4-methyl, 1,3-cyclohexanebis(methylamine), o-phenylenediamine (OPD), piperazine, p-phenylenediamine (PPD), 1,1'-biphenyl-4,4'-diamine (benzidine), polyethyleneimine, cyclohexane-1,2-diamine, 3,3',5,5'-tetramethylbenzidine, N,N'-diphenylbenzidine, 1,4-diaminonaphthalene, 1,5-diaminonaphthalene, benzene-1, It may be selected from the group consisting of 2,4-triamine, 1,4-diaminocyclohexane, 1,2,4,5-benzenetetramine, 1,8-diaminonaphthalene, 9,10-diaminophenanthrene, N-methyl-1,2-phenylenediamine, 2,5-dimethyl-1,4-phenylenediamine, 2-methyl-1,3-benzenediamine, N,N-dimethyl-1,2-phenylenediamine, [4-(aminomethyl)cyclohexyl]methylamine, 2-aminomethyl-cyclohexylamine, and mixtures thereof.

[0049] Preferred polyamines for the methods disclosed herein include m-phenylenediamine (MPD), m-phenylenediamine-4-methyl, 1,3-cyclohexanebis(methylamine), o-phenylenediamine (OPD), piperazine, p-phenylenediamine (PPD), 1,1'-biphenyl-4,4'-diamine (benzidine), polyethyleneimine, and mixtures thereof. In one embodiment, the aqueous suspension contains m-phenylenediamine. In another embodiment, piperazine was used as the polyamine in the aqueous suspension.

[0050] The aqueous suspension for impregnating the surface of the porous membrane substrate may include at least one phospholipid.

[0051] The concentration of the phospholipid in the aqueous phase may be in the range of about 10 μM to about 10 mM, or about 10 μM to about 9.5 mM, or about 10 μM to about 9.0 mM, or about 10 μM to about 8.5 mM, or about 10 μM to about 8.0 mM, or about 10 μM to about 7.5 mM, or about 10 μM to about 7.0 mM, or about 10 μM to about 6.5 mM, or about 10 μM to about 6.0 mM, or about 10 μM to about 5.5 mM, or about 10 μM to about 5.0 mM, or about 20 μM to about 4.5 mM, or about 30 μM to about 4.5 mM, or about 40 μM to about 4.5 mM, preferably about 50 μM to about 4.0 mM.

[0052] Advantageously, it has been found that the water permeability of composite membranes prepared according to the methods described herein can be optimized by providing an aqueous suspension containing at least one phospholipid at a concentration of about 50 μM to about 4.0 mM. In embodiments, the water permeability of membranes containing the phospholipid 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) is increased by at least about 60%, or preferably at least about 80%, compared to membranes without DOPC. The use of phospholipids to promote the interfacial polymerization reaction is believed to result in polyamide layers with increased effective membrane area, thereby increasing the water permeability of the composite membrane. The dispersion of phospholipids within the deposited polyamide layer is believed to contribute to the expansion of the interstitial space between the polyamide layer and the substrate, facilitating water transport through the membrane.

[0053] Natural or synthetic phospholipids, or mixtures thereof, can be used to prepare the composite membranes described herein. These include naturally occurring phospholipids obtained from eggs, E. coli lipid extracts, soybean lipid extracts, yeast lipid extracts, and mixtures thereof, as well as synthetic phospholipids such as phosphatidylcholine, phosphatidylserine, phosphatidylglycerol, phosphatidylethanolamine, or mixtures thereof. In embodiments, natural phosphatidylcholine was used to prepare the composite thin films. In one embodiment, a porous membrane substrate was impregnated with a suspension of egg phosphatidylcholine (PC).

[0054] The phospholipids suspended in the aqueous phase may contain acyl groups with saturated and / or unsaturated carbon chains.

[0055] The phospholipid has the following formula (I):

[0056] [ka]

[0057] wherein R1 and R2 can independently be a saturated or unsaturated aliphatic group having 10 to 50 carbon atoms, and R3 is

[0058] [ka]

[0059] (which is)

[0060] The saturated or unsaturated aliphatic groups R1 and R2 may independently contain 10 to 50 carbon atoms, or 10 to 45 carbon atoms, or 10 to 40 carbon atoms, or 10 to 35 carbon atoms, or 10 to 30 carbon atoms, or 10 to 28 carbon atoms, or 10 to 26 carbon atoms, or 12 to 26 carbon atoms, preferably 12 to 24 carbon atoms.

[0061] The substituent R1 can be a saturated or unsaturated aliphatic group, preferably having 14 to 24 carbon atoms, and the substituent R2 can be a saturated or unsaturated aliphatic group, preferably having 14 to 24 carbon atoms. In one embodiment, R1 and R2 are both unsaturated aliphatic groups having 17 carbon atoms. In another embodiment, R1 is a saturated aliphatic group having 15 carbon atoms, and R2 is an unsaturated aliphatic group having 17 carbon atoms.

[0062] Phospholipids that can be used in the methods described herein include 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC), 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE), 1,2-dioleoyl-sn-glycero-3-phospho-rac-(1-glycerol) (DOPG), L-α-phosphatidylcholine (egg PC), 1,2-ditetradecanoyl-sn-glycero-3-phosphocholine (DMPC), 2-oleoyl-1-palmitoyl-sn-glycero-3-phosphocholine (POPC), 1,2-Dilauroyl-sn-glycero-3-phosphocholine (DLPC), 1,2-Dimyristoyl-sn-glycero-3-phosphocholine (DMPC), 1,2-Dipalmitoyl-sn-glycero-3-phosphocholine (DPPC), 1,2-Distearoyl-sn-glycero-3-phosphocholine (DSPC), 1,2-Dilauroyl-sn-glycero-3-phospho-(1'-rac-glycerol) (sodium salt) (DLPG), 1,2-Dimyristoyl-sn-glycero-3-phospho-(1'-rac-glycerol) (sodium salt) ( DMPG), 1,2-dipalmitoyl-sn-glycero-3-phospho-(1'-rac-glycerol) (sodium salt) (DPPG), 1-palmitoyl-2-oleoyl-sn-glycero-3-phospho-(1'-rac-glycerol) (sodium salt) (POPG), 1,2-dimyristoyl-sn-glycero-3-phospho-L-serine (sodium salt) (DMPS), 1,2-dipalmitoyl-sn-glycero-3-phospho-L-serine (sodium salt) (DPPS), 1,2-distearoyl-sn-glycero-3-phospho-L- Serine (sodium salt) (DSPS), 1,2-dioleoyl-sn-glycero-3-phospho-L-serine (sodium salt) (DOPS), 1-palmitoyl-2-oleoyl-sn-glycero-3-phospho-L-serine (sodium salt) (POPS), 1,2-dilauroyl-sn-glycero-3-phosphate (sodium salt) (DLPA), 1,2-dimyristoyl-sn-glycero-3-phosphate (sodium salt) (DMPA), 1,2-dipalmitoyl-sn-glycero-3-phosphate (sodium salt) (DPPA), 1,2-Distearoyl-sn-glycero-3-phosphate (sodium salt) (DSPA), 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphate (sodium salt) (POPA), 1,2-dilauroyl-sn-glycero-3-phosphoethanolamine (DLPE), 1,2-dimyristoyl-sn-glycero-3-phosphoethanolamine (DMPE), 1,2-dipalmitoyl-sn-glycero-3-phosphoethanolamine (DPPE), 1,2-distearoyl-sn-glycero-3-phosphoethanolamine (DSPE), 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoethanolamine (POPE), 1,2-di-O-octadecenyl-3-trimethylammonium propane (chloride salt) (DOTMA), Escherichia coli lipid extract Extract, soybean lipid extract, yeast lipid extract, 1-palmitoyl-2-(dipyrrometheneboron difluoride)undecanoyl-sn-glycero-3-phosphocholine, 1,2-dioleoyl-sn-glycero-3-phospho-(1'-myo-inositol)(ammonium salt) (DOPI), 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoinositol(ammonium salt) (POPI), 1,2-dipalmitoyl-sn-glycero-3-phospho-(1'-myo-inositol)(ammonium salt) (DPPI), 1,1',2,2'-tetraoleoylcardiolipin (TOCL), 1,2-dioleoyl-sn-glycero-3-phosphoethanol (DOPEt), 1,2-dioleoyl-sn-glycero-3-phosphoethanol (DOPEt) (18:0 diethyl PC), or a combination thereof.

[0063] Preferably, the phospholipid can be selected from the group consisting of 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC), 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE), 1,2-dioleoyl-sn-glycero-3-phospho-rac-(1-glycerol) (DOPG), L-α-phosphatidylcholine (egg PC), 1,2-ditetradecanoyl-sn-glycero-3-phosphocholine (DMPC), 2-oleoyl-1-palmitoyl-sn-glycero-3-phosphocholine (POPC), and mixtures thereof. In one embodiment, the phospholipid is 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC). In another embodiment, the phospholipid is 2-ditetradecanoyl-sn-glycero-3-phosphocholine (DMPC).

[0064] After the impregnation step a), excess aqueous suspension may be removed from the surface of the porous membrane substrate. The excess aqueous suspension can be removed by rinsing, gas purging, or blowing before the contacting step b). Gas or compressed air can be used to purge or blow away excess aqueous suspension from the surface of the impregnated porous membrane substrate.

[0065] Alternatively, the removal of excess aqueous suspension can be achieved by rinsing the surface of the impregnated porous membrane substrate with an organic solvent. The organic solvent for rinsing can be a non-polar organic solvent. The organic solvent used for rinsing can be the same solvent as that used for the organic phase in contacting step b). Non-limiting examples of organic solvents that can be used to rinse the surface of the impregnated porous membrane substrate include cyclohexane, hexane, pentane, toluene, diethyl ether, ethyl acetate, chloroform, or dichloromethane. In an embodiment, the surface of the porous membrane substrate was rinsed with cyclohexane before contacting the impregnated membrane substrate with the organic phase containing at least one crosslinking agent.

[0066] The impregnated membrane substrate can then be contacted with an organic phase containing a monomer containing at least one crosslinking group (i.e., a crosslinker) to deposit a polyamide layer on the impregnated surface of the porous membrane substrate.

[0067] The organic phase used in the contacting step b) may be immiscible with the aqueous suspension of the impregnation step a) to promote the interfacial polymerization reaction. Therefore, the organic phase may comprise an organic solvent that is immiscible with water but capable of dissolving the crosslinker. The organic solvent may preferably be non-reactive or inert with the monomer containing at least one crosslinking group. The organic phase may further comprise a non-polar organic solvent. Organic solvents such as cyclohexane, hexane, pentane, toluene, diethyl ether, ethyl acetate, chloroform, or dichloromethane may be used in the organic phase. In an embodiment, the organic phase comprises cyclohexane. The use of an organic solvent immiscible with the aqueous suspension of the contacting step a) in the organic phase of step b) promotes the interfacial polymerization reaction between the two immiscible phases.

[0068] Contacting step b) can be carried out for a time sufficient to deposit a polyamide layer having a thickness of about 500 nm to about 4000 nm. Contacting step b) can be carried out for about 10 seconds to 10 minutes, or about 10 seconds to 9.5 minutes, or about 10 seconds to 9 minutes, or about 10 seconds to 8.5 minutes, or about 10 seconds to 8 minutes, or about 10 seconds to 7.5 minutes, or about 10 seconds to 7 minutes, or about 10 seconds to 6.5 minutes, or about 10 seconds to 6 minutes, or about 10 seconds to 5 minutes, or about 10 seconds to 4.5 minutes, or about 10 seconds to 4 minutes, or about 15 seconds to 4 minutes, or about 20 seconds to 4 minutes, or about 20 seconds to 3.5 minutes, or about 20 seconds to 3 minutes. The impregnated membrane substrate can be contacted with the organic phase for preferably about 30 seconds to 3 minutes.

[0069] The organic phase may include at least one crosslinking agent that reacts with the polyamine. As used herein, the term "crosslinking agent" refers to a monomer containing at least one crosslinking functional group (i.e., a monomer containing a functional group capable of crosslinking) that can be used to covalently bond two or more molecules or monomers to form a polyamide network. The crosslinking agent may be incorporated into the polyamide layer deposited on the substrate.

[0070] The organic phase may contain from about 0.00001% to 2% by weight, or from about 0.00005% to 2% by weight, or from about 0.0001% to 2% by weight, or from about 0.0002% to 2% by weight, or from about 0.0004% to 2% by weight, or from about 0.0006% to 2% by weight, or from about 0.0008% to 2% by weight, or from about 0.001% to 1.8% by weight, or from about 0.001% to 1.6% by weight, based on the weight of the organic phase. %, or about 0.001% to 1.4% by weight, or about 0.001% to 1.2% by weight, or preferably about 0.001% to 1% by weight, or about 0.005% to 1% by weight, or about 0.01% to 1% by weight, or about 0.01% to 0.8% by weight, or more preferably about 0.05% to 0.8% by weight, even more preferably about 0.1% to 0.8% by weight. In embodiments, the crosslinker is provided at a concentration of about 0.15% by weight based on the weight of the organic phase.

[0071] The crosslinker used in the methods described herein can contain one or more reactive functional groups capable of forming covalent bonds with polyamines. The crosslinker contains at least two reactive functional groups, or 2 to 10 reactive functional groups, or 2 to 9 reactive functional groups, or 2 to 8 reactive functional groups, or 2 to 7 reactive functional groups, or 2 to 6 reactive functional groups, or 2 to 5 reactive functional groups, or preferably 2 to 4 reactive functional groups, thereby forming an extended polymer network. In embodiments, the crosslinker contains three reactive functional groups.

[0072] The crosslinker may contain acyl halide or sulfonyl halide groups, preferably at least two acyl halide or sulfonyl halide groups. In an embodiment, a crosslinker having three acyl halide groups was dissolved in the organic phase.

[0073] The crosslinking agent is selected from the group consisting of trimesoyl chloride (1,3,5-benzenetricarbonyl trichloride), terephthalic acid chloride (terephthaloyl dichloride), isophthalic acid chloride (isophthaloyl dichloride), biphenyldicarboxylic acid chloride, naphthalenedicarboxylic acid dichloride, biphenyl-4,4-disulfonyl chloride, 1,3,6-naphthalenetrisulfonyl chloride, phthaloyl dichloride, adipoyl chloride, oxalyl chloride, malonyl chloride, and mixtures thereof. In embodiments, the crosslinking agent is trimesoyl chloride (1,3,5-benzenetricarbonyl trichloride).

[0074] An organic phase containing at least one crosslinker is contacted with the surface of a membrane impregnated with an aqueous mixture of at least one polyamine and at least one phospholipid, resulting in interfacial polymerization. The interfacial polymerization occurs on the surface of the porous membrane substrate, depositing a polyamide layer thereon. A composite membrane structure having a thin polyamide membrane is thereby obtained by the method described herein.

[0075] Accordingly, the present disclosure also provides a composite membrane comprising: a) at least one porous membrane substrate having nano- or micro-sized pores; and b) at least one polyamide layer disposed on a surface of the porous membrane substrate, the polyamide layer comprising at least one phospholipid dispersed therein and being an interfacial polymerization product.

[0076] In particular, the polyamide layer can be formed by interfacial polymerization between two immiscible phases: an aqueous phase containing at least one polyamine and an organic phase containing a monomer containing at least one crosslinking group, the aqueous phase optionally further containing suspended phospholipids, thereby allowing the phospholipids to be dispersed in the resulting polyamide layer.

[0077] The aqueous phase containing at least one polyamine and at least one suspended phospholipid may be substantially free of transmembrane proteins and their analogs, such as aquaporins. This results in a deposited polyamide layer that may also be substantially free of such proteins. Specifically, the polyamide layer formed by the interfacial polymerization reaction does not contain aquaporins.

[0078] The interfacial polymerization reactions described herein can result in the deposition of a polyamide layer having a rough surface. In embodiments, the formation of ridges and valleys is observed on the surface of the deposited polyamide layer. The composite membrane can comprise a polyamide layer having a height of about 50 nm to 4000 nm, and can be a wholly aromatic or semi-aromatic polyamide layer.

[0079] Surprisingly, when an aqueous phase containing at least one phospholipid and one aromatic polyamine is used in combination with an aromatic crosslinker in the interfacial polymerization reaction, a wholly aromatic polyamide layer with larger leaf-like features or structures is obtained. The formation of such a "wholly aromatic" polyamide layer results in an increase in the apparent height or thickness of the polyamide layer. Specifically, the height of a wholly aromatic polyamide layer formed in the presence of a phospholipid can range from about 200 nm to about 4000 nm, measured from the surface of the porous membrane substrate (i.e., the bottom surface of the polyamide layer) to the top of the polyamide layer. The presence of leaf-like features or structures is believed to increase the effective membrane area of ​​the composite, thereby facilitating the passage of water molecules through the membrane. This advantageously contributes to an increase in water permeability of about 60% or more for composite membranes containing a wholly aromatic polyamide layer.

[0080] The formation of these leaf-like features and the increase in thickness of the polyamide layer are believed to be due to the dispersion of phospholipids in the aqueous phase during the interfacial polymerization reaction. In comparison, exemplary polyamide layers with larger leaf-like structures formed in the presence of phospholipids exhibit heights of 200 nm to 4000 nm and surface roughnesses of 208 ± 50 nm. This is a significant improvement over films formed without phospholipids, which typically exhibit apparent heights of approximately 200 nm to 1000 nm and surface roughnesses of 152 ± 66 nm.

[0081] Furthermore, it has been surprisingly found that the water permeability of composite membranes comprising a semi-aromatic polyamide layer is similarly increased compared to membranes formed without phospholipids. In contrast to the fully aromatic polyamide layers described above, the apparent height of such semi-aromatic layers formed from aliphatic piperazines and aromatic crosslinkers in the presence of phospholipids is typically less than 100 nm. It is hypothesized that the increased permeability of such semi-aromatic polyamide layers is due to the expansion of the interstitial space between the polyamide layer and the surface of the substrate, which allows the passage of water molecules through the membrane.

[0082] Thus, the composite membranes disclosed herein can have a thickness of 200 nm to 4000 nm when a wholly aromatic polyamide layer containing phospholipids is obtained, or a thickness of less than 100 nm when a semi-aromatic polyamide layer with dispersed phospholipids is formed. The wholly aromatic polyamide layer can have large leaf-like structures or features, while the semi-aromatic polyamide layer can be observed as a thin, uniform to wavy structure.

[0083] Advantageously, the presence of phospholipids promotes the reaction between the two monomers, resulting in a highly cross-linked polyamide layer that contributes to high solute rejection rates of about 94% to 97% at low operating pressures of about 2 bar, despite the high water permeability of the membrane. 2 and 32,000 cm 2It was demonstrated that membrane modules having an effective area of ​​about 1000 kJ / bar and a water permeability of about 6 LMH / bar maintained sodium chloride rejection rates of about 94% to 97%. The low solute passage rate and high water permeability of the composite membranes can also be observed from the ratio of solute permeability to water permeability (B / A ratio), which is about 5 kPa for the composite membranes described herein and 17 kPa for the membranes formed without the phospholipids described herein.

[0084] When used to filter wastewater containing organic contaminants, the composite membrane advantageously maintained high solute rejection and water permeability for up to 120 days. 2 and 300cm 2 A membrane module with an effective area of ​​approximately 1000 mW exhibited a water flux of approximately 20 LMH and a solute rejection rate of approximately 96.5% at an applied pressure of 2.9 bar to 3.5 bar when used to filter wastewater containing approximately 7 mg / L to 8 mg / L of total organic matter. This performance was maintained for 120 days before the membrane needed to be cleaned and replaced.

[0085] Thus, the present disclosure provides a method for preparing a composite membrane having a polyamide layer deposited on the surface of a porous membrane substrate. The polyamide layer can be formed by an interfacial polymerization reaction between two immiscible phases: an aqueous phase containing a mixture of at least one polyamine and at least one phospholipid, and an organic phase containing a crosslinker. The composite membranes described herein advantageously exhibit low solute passage rates despite high water permeability.

[0086] The composite membranes described herein can be used to fabricate a variety of membrane modules as operationally desired. In embodiments, hollow fiber or flat sheet membranes were prepared comprising the composite membranes described herein. [Example]

[0087] Example 1 Polyetherimide (PEI) hollow fiber substrate with a lumen coated with a polyamide layer containing 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) Materials and Methods chemicals 1,2-Dioleoyl-sn-glycero-3-phosphocholine (DOPC, 25 mg / ml, Avanti Polar Lipids, Alabama, USA) was used to prepare an aqueous mixture containing both MPD and lipid. Polyetherimide (PEI Ultem 1000, GE Plastic, USA) and N-methyl-2-pyrrolidone (NMP, >99.5%, CAS#872-50-4, Merck Chemicals, Singapore) were used as the substrate material and solvent, respectively.

[0088] Ultrapure water and tap water were used as the bore fluid and external coagulant, respectively.

[0089] 1,3,5-Benzene-tricarbonyl trichloride (TMC, CAS#4422-95-1, Sigma-Aldrich) and m-phenylenediamine (MPD, CAS#108-45-2, Sigma-Aldrich) were used as monomers for interfacial polymerization.

[0090] Cyclohexane (CAS#110-82-7, Merck Chemicals, Singapore) was used as the solvent for TMC.

[0091] Sodium chloride (Merck) was used as the feed solution for the salt rejection tests.

[0092] Membrane preparation Hollow fiber PEI substrates with inner and outer diameters of 800 μm and 1000 μm were fabricated under dry and wet spinning conditions. Different numbers of fibers were assembled into modules of different sizes. For example, 5 to 30 fibers were assembled into half-inch modules. The modules were then vertically fixed on iron supports with extension clamps. DOPC from a 20 mM stock solution was mixed with the MPD solution. In the interfacial polymerization step, a 1.2 wt% MPD solution containing DOPC at concentrations of approximately 50 μM to approximately 4 mM was contacted with the luminal surface of the PEI fibers. Subsequently, excess MPD solution was removed by pumping fresh cyclohexane onto the luminal surface. Next, a 0.15 wt% TMC cyclohexane solution was pumped onto the luminal surface to react with the MPD residue. The as-prepared membrane modules were dried in air and then immersed in ultrapure water for storage.

[0093] Membrane performance The water permeability and salt rejection of the membrane module were then measured. Ultrapure water was used to test the water permeability of the membrane, and a 500 mg / L NaCl feed solution was used to measure the sodium chloride rejection.

[0094] A pressure of 2 bar was applied across the membrane module, and a cross-flow velocity of approximately 20 cm / s was maintained using a gear pump. All measurements were carried out at room temperature (23±1°C).

[0095] The same conditions (i.e., 2 bar, 23±1° C.) were applied to measure the water permeability and salt rejection of a control membrane prepared according to the method above except that no DOPC was present in the MPD solution.

[0096] The results of the water permeability and desalination performance of the membranes are shown in Table 1. The membrane incorporating DOPC (PEI-DOPC) showed a much higher water permeability (8.5±1.5 L / m 2 / hour / bar (LMH / bar) compared to the control membrane (1.1±0.2 LMH / bar).

[0097] The addition of DOPC lipids also improved NaCl rejection from 90% to over 95%. The solute permeability to water permeability ratio (B / A) of the PEI-DOPC membrane decreased to approximately 5 kPa. This low value indicates a very low solute passage rate despite the high water permeability of this DOPC-based membrane. In contrast, it is noteworthy that the corresponding ratio for the control membrane was 17, at least three times higher. This is a completely unexpected result.

[0098] [Table 1]

[0099] Membrane characterization Field emission scanning electron microscope (FESEM) and atomic force microscope (AFM) were used to characterize the morphology of the membrane selective layer.

[0100] The membrane samples were freeze-dried (JSM-7600F, JEOL, Japan) and coated with a uniform layer of platinum before FESEM imaging at 2 kV (coating was performed at a voltage of 20 mV and for 45 seconds). To obtain cross-sections of the membranes, they were fractured in liquid nitrogen before drying. The surface roughness of the membranes was measured using an AFM (Park XE-100, Korea). Micrographs with a scan size of 10 μm × 10 μm and a resolution of 128 pixels were obtained in Non-Contact Mode™.

[0101] FESEM images (Figure 2) show that the polyamide selective layer of the lipid-based membrane has a larger leaf-like structure when compared to the control membrane (no DOPC).

[0102] The larger leaf-like structure resulted in a significantly larger overall "thickness" of approximately 0.5 μm to 4 μm. This may also contribute to an increased effective surface area in contact with the water feed. AFM micrographs are shown in Figures 3a and 3b. Notably, while small "ridge and valley" structures were observed for the control membrane, the DOPC-incorporated membrane exhibited a relatively large surface structure with higher and / or longer ridges and deeper, wider grooves (valleys), resulting in the appearance of leaf-like features. This result is consistent with the observations from FESEM images. The results showed that the root-mean-square roughness for the lipid-based membrane and the control membrane were 208 ± 50 nm and 152 ± 66 nm, respectively, indicating that the surface of the composite membrane formed with phospholipids was rougher. The rougher surface and leaf-like features of the composite membrane formed with phospholipids likely contribute to a larger effective membrane area, facilitating water transport through the membrane.

[0103] Scalability The performance of membrane modules made with different numbers of fibers is summarized in Table 2. The membrane area was 26 cm 2 ~3.2m 2 (4 inch module, see Figure 4). Using the inventive membrane synthesis method described herein, small modules (300 cm 2 It has been found that a permeability of about 8±1.5 LMH / bar can be maintained for modules (areas below) and that permeabilities of up to 6 LMH / bar can be achieved for larger modules (i.e., 2 inch and 4 inch modules).

[0104] Sodium chloride rejection is maintained at 94%-96% for all module sizes at a low applied pressure of 2 bar. At an increased operating pressure of 5 bar, salt rejection rates of over 97% can be achieved.

[0105] The performance of the aquaporin-based membranes was compared to lipid-containing membranes of the present invention, and the data are shown in Table 2 below.

[0106] The entries ABM_1 and ABM_2 in Table 2 refer to PEI membrane substrates coated (lumen surface) with a polyamide selective layer containing the protein aquaporin Z (AQP-Z), a commercially available protein (UniProtKB-P60844) derived from Escherichia coli (K12 strain). AQP-Z was reconstituted into vesicles / proteoliposomes before incorporation into the membrane selective layer. The molar ratio of AQP-Z to lipid was 1:400 for ABM_1 and ABM_2, respectively.

[0107] The entries PEI_500 and PEI_3200 refer to PEI membranes with lipid-containing polyamide layers prepared according to the method described above, with PEI_500 scaled up to a 2-inch module containing 500 hollow fibers and PEI_3200 scaled up to a 4-inch module containing 3200 hollow fibers.

[0108] In particular, it is observed that both the ABM and the lipid-based membranes of the present invention exhibit comparable water permeability and salt rejection rates.

[0109] Because the substrate used to fabricate both membranes is the same (i.e., PEI), one might expect that thin film layers formed with the addition of lipids or AQPs would yield similar performance in terms of permeability and solute rejection. However, one advantage of the lipid-containing membranes of the present invention is that the composite membranes are not dependent on the properties or quality of the biomolecules. Instead, the permeability / rejection performance of the composite membranes described herein can be easily fine-tuned, for example, by adjusting the concentration of lipids in the aqueous phase during synthesis. In contrast, the performance of AQP-based membranes is highly dependent on the biological properties and purity of the proteins used.

[0110] [Table 2]

[0111] For the above measurements, water permeability was tested using ultrapure water at an applied pressure of 2 bar. Sodium chloride rejection was tested using a 500 mg / L NaCl solution at an applied pressure of 2 bar, and a 1000 mg / L NaCl solution at an applied pressure of 5 bar.

[0112] Industrial Testing The long-term performance of the lipid-based membrane was tested using actual wastewater collected from a wastewater treatment plant in Singapore. This was the UF filtrate of secondary effluent, also known as NEWater RO feed. The total organic carbon (TOC) content of the feedwater was approximately 7 mg / L to 8 mg / L. During long-term operation, the feedwater was changed every 10 to 14 days. System flushing was performed when the feedwater was changed, and chemical cleaning (acid / base) was performed monthly.

[0113] The membrane flux and rejection performance are shown in Figures 5a and 5b. During 120 days of operation, the water flux was maintained at 20 ± 1 LMH at an applied pressure of 2.9 bar to 3.5 bar. The freshly inserted or cleaned membrane can achieve a conductivity rejection of 96%, which increases to about 98% after one day of operation. This may be due to the formation of a thin layer of foulants deposited on the membrane surface, which helps to seal microdefects in the membrane or enhance electrostatic interactions.

[0114] After each cleaning, the removal rate returned to approximately 96%, demonstrating the effectiveness of the cleaning. A TOC removal rate of approximately 96.5 ± 0.5% was maintained throughout the run.

[0115] Example 2 Polyetherimide (PEI) hollow fiber substrate coated with a polyamide selective layer containing L-α-phosphatidylcholine (egg PC) The method of membrane preparation was the same as that used in Example 1, except that egg PC was used instead of DOPC.

[0116] The membrane performance of egg PC-containing membranes is shown in Table 3. Similar to the DOPC-based membranes, the addition of egg PC to the MPD solution was found to increase the membrane water permeability and salt rejection compared to a control membrane prepared similarly but without the presence of egg PC.

[0117] The water permeability of the membrane loaded with egg PC can reach about 8 LMH / bar, and the sodium chloride rejection rate increases to about 94% at an applied pressure of 2 bar.

[0118] [Table 3]

[0119] For the measurements in Table 3, five fibers were assembled into a half-inch membrane module (membrane effective area approximately 26 cm 2 The water permeability was measured with ultrapure water, and the salt rejection was measured with a 500 mg / L NaCl feed solution. The applied pressure was 2 bar.

[0120] Example 3 PEI hollow fiber substrate coated with a polyamide layer containing 1,2-ditetradecanoyl-sn-glycero-3-phosphocholine (DMPC) In this example, the phospholipid 1,2-ditetradecanoyl-sn-glycero-3-phosphocholine ("DMPC") was used for membrane preparation. The synthesis method was the same as in Examples 1 and 2, in which a selected polyamide layer was formed on the lumen of a PEI hollow fiber substrate. The only difference was the change in lipid type.

[0121] Similarly, a control membrane was synthesized using the same protocol, except that DMPC was not present in the aqueous phase. Compared to the control membrane formed without lipid, the DMPC-containing membrane exhibits an increase in water permeability of approximately 6.3 LMH / bar compared to 1.1 LMH / bar for the control membrane. NaCl rejection also improved from 90% to approximately 95.5%, as summarized in Table 4 below. DMPC / PEI-1 and DMPC-PEI-2 are two replicates fabricated under the same conditions.

[0122] [Table 4]

[0123] The effective membrane area is approximately 30.6 cm per module. 2 (5 fibers per module). Permeability (LMH / bar) was measured using ultrapure water. 500 mg / L NaCl feed was used for salt rejection measurements. Applied pressure was 2 bar.

[0124] Example 4 Polyethersulfone (PES) hollow fiber substrate coated with a polyamide layer containing egg PC The membrane preparation procedure was the same as in Example 2, except that a polyethersulfone (PES) porous membrane was used as the support layer.

[0125] PES hollow fiber substrates were fabricated by dry jet-wet spinning based on the non-solvent-induced phase separation (NIPS) method. The resulting fibers had inner / outer diameters of 780 μm / 1100 μm. The interfacial polymerization used to form the selective layer was the same as that described in Example 2.

[0126] Two half-inch membrane modules, each containing five PES fibers, were used for the performance evaluation. The effective membrane area was approximately 26 cm for both modules. 2 One module contained PES fibers coated with a polyamide layer containing egg PC, and the other module contained control PES fibers (no egg PC).

[0127] The water permeability was measured with ultrapure water and the salt rejection was measured with a 500 mg / L NaCl feed solution. The applied pressure was 2 bar.

[0128] The addition of egg PC to the MPD solution was found to significantly increase the water transport efficiency, as shown in Table 5. The water permeability increased to 4 LMH / bar for egg PC-based RO membranes with PES substrates compared to 0.8 LMH / bar in the absence of egg PC.

[0129] As in the previous example, NaCl rejection improved from 92% to 96% when egg PC was present.

[0130] [Table 5]

[0131] Example 5 Polyetherimide (PEI) flat substrate with a DOPC-containing polyamide layer The lipid-based membranes of the present invention can also be provided in a flat plate configuration.

[0132] In this example, a flat membrane substrate consisting of a PEI layer on a nonwoven fabric was used. A dope solution consisting of PEI and NMP was poured onto the nonwoven fabric (supported by a glass plate) and a 150 μm-high casting blade was applied to create a thin film on the glass. The coated film was then quickly immersed in a tap water bath, causing phase inversion and forming a membrane substrate.

[0133] The polyamide selective layer was then formed by interfacial polymerization using MPD and TMC. As in the previous example, DOPC was added to the MPD solution so that the aqueous mixture used in the interfacial polymerization reaction contained lipid.

[0134] A comparison of the DOPC-based membrane with the control membrane (no added DOPC) is shown in Table 6. It can be seen that the hydraulic conductivity increased by approximately 60%, and the NaCl rejection rate also improved from 91.5% to 93.6% with the addition of lipid.

[0135] [Table 6]

[0136] For performance evaluation, a 500 mg / L NaCl feed was used for salt rejection measurements. The applied pressure was 10 bar.

[0137] The membrane filtration cell is approximately 42 cm 2(Sterlitech's CF042 membrane cell).

[0138] Standard deviations are based on the results of at least two independent samples.

[0139] Example 6 Nanofiltration (NF) membranes with PEI hollow fiber substrates coated with a DOPC-containing polyamide layer In this example, PEI hollow fibers were used as the membrane substrate.

[0140] To fabricate DOPC-based NF membranes (PEI-DOPC-NF), the luminal surface of the substrate was first contacted with a piperazine (PIP) solution containing DOPC for 30 min.

[0141] Excess PIP solution was washed from the luminal surface by pumping fresh cyclohexane through the hollow fiber.

[0142] Finally, a cyclohexane solution containing TMC was delivered to the inner surface of the lumen to react with the PIP residues to form an NF-removing layer.

[0143] As a control, a NF membrane without DOPC was also prepared and named PEI-control-NF.

[0144] The performance of these NF membranes is shown in Table 7. Two commercially available NF membranes are also listed for comparison. GE-Osmonics HL is a commercially available NF membrane provided by GE, and NTR-7450 NF membrane was supplied by Nitto Denko Corporation.

[0145] The PEI-control-NF membrane (without lipid) exhibited a water permeability of 15 LMH / bar but a low rejection of 80.2% for MgSO. In comparison, the membrane according to the present invention ("PEI-DOPC-NF") exhibited slightly better water permeability (15.5 LMH / bar) and significantly better salt rejection (93.3% based on MgSO).

[0146] Furthermore, it is noteworthy that both NF membranes (control and DOPC-containing) outperformed the commercial membrane in terms of the balance between water permeability and solute rejection, even at significantly lower operating pressures.

[0147] [Table 7]

[0148] a. For the above results, the water permeability of the NF membrane was measured using ultrapure water at an applied pressure of 2 bar. b. For salt rejection tests, a 1000 mg / L MgSO4 feed solution was used to measure salt rejection for all four membranes. c. The membrane effective area is approximately 30.6 cm for PEI-DOPC-NF and PEI-control-NF. 2 (5 fibers), 42 cm for GE-Osmonics HL membrane and NTR-7450 membrane 2 It was. d. When a similar operating pressure of 7.6 bar or higher is used for the DOPC-PEI-NF membrane, the membrane rejection rate for MgSO4 is estimated to be greater than 98.5%.

[0149] Example 7 Osmotically driven (OD) membranes based on PEI hollow fiber substrates coated with a DOPC-containing polyamide layer A porous PEI substrate was developed to fabricate lipid-based osmotically driven (OD) membranes. This substrate has a lower density structure compared to RO / NF membrane substrates. The preparation of the removal layer was similar to that described in Example 1. The control membrane (without lipid) and lipid-based membranes are named OD membrane and DOPC-OD membrane, respectively.

[0150] A comparison of the two membranes is shown in Table 8. It can be seen that the addition of DOPC resulted in a more permeable selective layer (about 5.8 LMH / bar for the DOPC-OD membrane compared to 4.1 LMH / bar for the OD membrane).

[0151] When the membranes were operated in forward osmosis (FO) mode (active layer on the feed side, AL-FS orientation), the water flux was 30 LMH and 25 LMH, i.e., the addition of DOPC resulted in a 20% increase in water flux. In pressure retarded osmosis (PRO) studies (active layer on the draw side, AL-DS orientation) with an applied pressure of 12.5 bar on the draw side, the power density (W / m) was 1.27 for the DOPC-based OD membranes. 2 ) can be increased by about 8%.

[0152] [Table 8]

[0153] For the above tests, the OD membrane and DOPC-OD membrane were assembled into membrane modules each consisting of 15 fibers. Each module was approximately 40.6 cm 2 (The inner and outer diameters of the fibers are 392 μm and 605 μm, respectively).

[0154] The RO test used a 500 mg / L NaCl feed solution delivered at a cross-flow rate of 200 ml / min. The applied pressure was 2 bar.

[0155] For the FO test, the feed ultrapure water was circulated at 100 ml / min (lumen) and the 1 M NaCl draw solution was circulated at 1000 ml / min (shell).

[0156] For the PRO test, ultrapure water feed was circulated at 1000 ml / min (shell) and 1 M NaCl working solution was circulated at 100 ml / min (lumen). The applied pressure on the working solution side was 12.5 bar. [Industrial Applicability]

[0157] The methods for preparing the composite membranes described herein can be used for the industrial production and assembly of membrane modules that can be used in water filtration systems. The absence of transmembrane proteins in the preparation of the composite membranes disclosed herein allows for better quality control to be achieved during the industrial fabrication of the composite membranes.

[0158] The composite membranes obtained by the methods described herein can be used as nanofiltration membranes and osmotically driven membranes in water filtration and purification systems.

[0159] Therefore, it can be seen that the composite membrane and method of manufacturing the same according to the present embodiment have the advantage of providing a composite membrane having high water permeability while maintaining low solute passage. While exemplary embodiments have been presented in the above detailed description of the invention, it should be understood that many variations exist.

[0160] Furthermore, it should be understood that the exemplary embodiments are merely examples and are not intended to limit the scope, applicability, operation, or configuration of the invention in any way. Rather, the foregoing detailed description is intended to provide those skilled in the art with a convenient roadmap for practicing the exemplary embodiments of the invention, and it will be understood that various changes can be made in the function and arrangement of elements and methods of operation described in the exemplary embodiments without departing from the scope of the invention as defined in the appended claims.

Claims

1. 1. A method for preparing a composite membrane, comprising: a) impregnating the surface of a porous membrane substrate with an aqueous suspension comprising a mixture of at least one polyamine and at least one phospholipid; b) contacting the impregnated surface with an organic phase containing a monomer comprising at least one crosslinking group selected from an acyl halide group, a sulfonyl halide group, or a combination thereof, thereby depositing a polyamide layer on the impregnated surface; Including, 10. A method for preparing a composite membrane, wherein said polyamide layer comprises said at least one phospholipid dispersed therein, said polyamide layer being an interfacial polymerization product.

2. The method of claim 1 , wherein the monomer comprises at least two acyl halide or sulfonyl halide groups.

3. 3. The method of claim 1 or 2, wherein, prior to contacting step b), excess aqueous suspension is removed from the surface of the porous membrane substrate by a rinsing or blowing step.

4. 4. The method according to claim 1, wherein the aqueous suspension comprises the phospholipid in a molar concentration of 10 μM to 10 mM.

5. 5. The method according to claim 1, wherein the aqueous suspension comprises the phospholipids in a molar concentration of from 50 μM to 4 mM.

6. 6. The method according to any one of claims 1 to 5, wherein the aqueous suspension comprises the polyamine in a concentration of from 0.001% to 10% by weight.

7. 7. The method according to any one of claims 1 to 6, wherein the aqueous suspension comprises the polyamine in a concentration of from 0.5% to 3% by weight.

8. The method of any one of claims 1 to 7, wherein the aqueous suspension is free of transmembrane proteins.

9. The method of claim 8 , wherein the aqueous suspension is aquaporin-free.

10. The phospholipid may be 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC), 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE), 1,2-dioleoyl-sn-glycero-3-phospho-rac-(1-glycerol) (DOPG), L-α-phosphatidylcholine (egg PC), 1,2-ditetradecanoyl-sn-glycero-3-phosphocholine (DMPC), 2-oleoyl-1-palmitoyl-sn-glycero-3-phosphocholine (POPC), 1,2-dilauroyl-sn- Glycero-3-phosphocholine (DLPC), 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC), 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC), 1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC), 1,2-dilauroyl-sn-glycero-3-phospho-(1'-rac-glycerol) (sodium salt) (DLPG), 1,2-dimyristoyl-sn-glycero-3-phospho-(1'-rac-glycerol) (sodium salt) (DMPG), 1,2 -dipalmitoyl-sn-glycero-3-phospho-(1'-rac-glycerol) (sodium salt) (DPPG), 1-palmitoyl-2-oleoyl-sn-glycero-3-phospho-(1'-rac-glycerol) (sodium salt) (POPG), 1,2-dimyristoyl-sn-glycero-3-phospho-L-serine (sodium salt) (DMPS), 1,2-dipalmitoyl-sn-glycero-3-phospho-L-serine (sodium salt) (DPPS), 1,2-distearoyl-sn-glycero-3-phospho-L-serine (sodium salt) thorium salt) (DSPS), 1,2-dioleoyl-sn-glycero-3-phospho-L-serine (sodium salt) (DOPS), 1-palmitoyl-2-oleoyl-sn-glycero-3-phospho-L-serine (sodium salt) (POPS), 1,2-dilauroyl-sn-glycero-3-phosphate (sodium salt) (DLPA), 1,2-dimyristoyl-sn-glycero-3-phosphate (sodium salt) (DMPA), 1,2-dipalmitoyl-sn-glycero-3-phosphate (sodium salt) (DPPA), 1,2-distearoyl-sn-glycero-3-phosphate (sodium salt) (DSPA), 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphate (sodium salt) (POPA), 1,2-dilauroyl-sn-glycero-3-phosphoethanolamine (DLPE), 1,2-dimyristoyl-sn-glycero-3-phosphoethanolamine (DMPE), 1,2-dipalmitoyl-sn-glycero-3-phosphoethanolamine (DPPE), 1,2-distearoyl-sn-glycero-3-phosphoethanolamine (DSPE), 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoethanolamine (POPE), 1,2-di-O-octadecenyl-3-trimethylammonium propane (chloride salt) (DOTMA), Escherichia coli lipid extract Soybean lipid extract, yeast lipid extract, 1-palmitoyl-2-(dipyrrometheneboron difluoride)undecanoyl-sn-glycero-3-phosphocholine, 1,2-dioleoyl-sn-glycero-3-phospho-(1'-myo-inositol) (ammonium salt) (DOPI), 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoinositol (ammonium salt) The method according to any one of claims 1 to 9, wherein the hydroxybenzoate is selected from the group consisting of 1,2-dipalmitoyl-sn-glycero-3-phospho-(1'-myo-inositol) (POPI), 1,2-dipalmitoyl-sn-glycero-3-phospho-(1'-myo-inositol) (ammonium salt) (DPPI), 1,1',2,2'-tetraoleoylcardiolipin (TOCL), 1,2-dioleoyl-sn-glycero-3-phosphoethanol (DOPEt), 1,2-dioleoyl-sn-glycero-3-phosphoethanol (DOPEt) (18:0 diethylPC), or a combination thereof.

11. 11. The method of claim 10, wherein the phospholipid is selected from the group consisting of 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC), 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE), 1,2-dioleoyl-sn-glycero-3-phospho-rac-(1-glycerol) (DOPG), L-α-phosphatidylcholine (egg PC), 1,2-ditetradecanoyl-sn-glycero-3-phosphocholine (DMPC), 2-oleoyl-1-palmitoyl-sn-glycero-3-phosphocholine (POPC), and mixtures thereof.

12. The phospholipid has the formula (I): 【Chemistry 1】 (In the formula, R １ represents a saturated or unsaturated aliphatic group having 14 to 24 carbon atoms, R ２ represents a saturated or unsaturated aliphatic group having 14 to 24 carbon atoms, R ３ teeth, 【Chemistry 2】 The method of any one of claims 1 to 11, wherein

13. 13. The method of any one of claims 1 to 12, wherein the polyamine is a monomer comprising at least two amine groups, the amine groups being independently primary or secondary amine groups.

14. 14. The method of claim 13, wherein the polyamine is selected from the group consisting of m-phenylenediamine (MPD), m-phenylenediamine-4-methyl, 1,3-cyclohexanebis(methylamine), o-phenylenediamine (OPD), piperazine, p-phenylenediamine (PPD), 1,1'-biphenyl-4,4'-diamine (benzidine), polyethyleneimine, and mixtures thereof.

15. 15. The method of any one of claims 1 to 14, wherein the monomer comprising at least one crosslinking group is selected from the group consisting of trimesoyl chloride (1,3,5-benzenetricarbonyl trichloride), terephthalic acid chloride, isophthalic acid chloride, biphenyldicarboxylic acid chloride, naphthalenedicarboxylic acid dichloride, biphenyl-4,4'-disulfonyl chloride, 1,3,6-naphthalenetrisulfonyl chloride, and mixtures thereof.

16. 16. The method according to any one of claims 1 to 15, wherein the organic phase comprises the monomer comprising at least one crosslinking group in a concentration of from 0.00001% to 2% by weight.

17. 17. The method according to any one of claims 1 to 16, wherein the organic phase comprises the monomer comprising at least one crosslinking group in a concentration of from 0.001% to 1% by weight.

18. 18. The method of any one of claims 1 to 17, wherein said contacting step (b) is carried out for a time sufficient to deposit said polyamide layer to a thickness of from 50 nm to 4000 nm.

19. 19. The method of claim 18, wherein said contacting step b) is carried out for a period of from 10 seconds to 10 minutes.

20. 20. The method according to any one of claims 1 to 19, wherein the polyamide layer is a wholly aromatic polyamide layer having a thickness of 200 nm to 4000 nm, or the polyamide layer is a semi-aromatic polyamide layer having a thickness of less than 100 nm.

21. 21. The method of any one of claims 1 to 20, wherein the organic phase further comprises an organic solvent that does not react with the monomer comprising at least one crosslinking group.

22. a) at least one porous membrane substrate having nano-sized or micro-sized pores; b) at least one polyamide layer disposed on a surface of the porous membrane substrate; Equipped with A composite membrane, wherein the polyamide layer comprises at least one phospholipid dispersed therein, and the polyamide layer is an interfacial polymerization product.

23. 23. The composite membrane of claim 22, wherein the polyamide layer is formed by interfacial polymerization between two immiscible phases.

24. 24. The composite membrane of claim 23, wherein the two immiscible phases comprise an aqueous phase containing at least one polyamine and an organic phase containing a monomer comprising at least one crosslinking group selected from an acyl halide group, a sulfonyl halide group, or a combination thereof.

25. 25. The composite membrane of claim 24, wherein the monomer comprises at least two acyl halide or sulfonyl halide groups.

26. 25. The composite membrane of claim 24, wherein the aqueous phase further comprises a phospholipid suspended therein.

27. A composite membrane according to any one of claims 22 to 26, wherein said phospholipids are provided in said aqueous phase at a molar concentration of between 10 μM and 10 mM.

28. 28. The composite membrane according to any one of claims 22 to 27, wherein the aqueous suspension comprises the phospholipids in a molar concentration of from 50 μM to 4 mM.

29. 29. The composite membrane of any one of claims 22 to 28, wherein the interfacial polymerization occurs on the surface of the porous membrane substrate, whereby the polyamide layer is deposited thereon.

30. The phospholipid may be 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC), 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE), 1,2-dioleoyl-sn-glycero-3-phospho-rac-(1-glycerol) (DOPG), L-α-phosphatidylcholine (egg PC), 1,2-ditetradecanoyl-sn-glycero-3-phosphocholine (DMPC), 2-oleoyl-1-palmitoyl-sn-glycero-3-phosphocholine (POPC), 1,2-dilauroyl-sn- Glycero-3-phosphocholine (DLPC), 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC), 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC), 1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC), 1,2-dilauroyl-sn-glycero-3-phospho-(1'-rac-glycerol) (sodium salt) (DLPG), 1,2-dimyristoyl-sn-glycero-3-phospho-(1'-rac-glycerol) (sodium salt) (DMPG), 1,2 -dipalmitoyl-sn-glycero-3-phospho-(1'-rac-glycerol) (sodium salt) (DPPG), 1-palmitoyl-2-oleoyl-sn-glycero-3-phospho-(1'-rac-glycerol) (sodium salt) (POPG), 1,2-dimyristoyl-sn-glycero-3-phospho-L-serine (sodium salt) (DMPS), 1,2-dipalmitoyl-sn-glycero-3-phospho-L-serine (sodium salt) (DPPS), 1,2-distearoyl-sn-glycero-3-phospho-L-serine (sodium salt) thorium salt) (DSPS), 1,2-dioleoyl-sn-glycero-3-phospho-L-serine (sodium salt) (DOPS), 1-palmitoyl-2-oleoyl-sn-glycero-3-phospho-L-serine (sodium salt) (POPS), 1,2-dilauroyl-sn-glycero-3-phosphate (sodium salt) (DLPA), 1,2-dimyristoyl-sn-glycero-3-phosphate (sodium salt) (DMPA), 1,2-dipalmitoyl-sn-glycero-3-phosphate (sodium salt) (DPPA), 1,2-distearoyl-sn-glycero-3-phosphate (sodium salt) (DSPA), 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphate (sodium salt) (POPA), 1,2-dilauroyl-sn-glycero-3-phosphoethanolamine (DLPE), 1,2-dimyristoyl-sn-glycero-3-phosphoethanolamine (DMPE), 1,2-dipalmitoyl-sn-glycero-3-phosphoethanolamine (DPPE), 1,2-distearoyl-sn-glycero-3-phosphoethanolamine (DSPE), 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoethanolamine (POPE), Escherichia coli lipid extract, soybean lipid extract, yeast lipid extract, 1-palmitoyl-sn-glycero-3-phosphoethanolamine Lumitoyl-2-(dipyrrometheneboron difluoride)undecanoyl-sn-glycero-3-phosphocholine, 1,2-dioleoyl-sn-glycero-3-phospho-(1'-myo-inositol) (ammonium salt) (DOPI), 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoinositol (ammonium salt) (POPI), 1,2-dipalmitoyl-sn-glycero-3-phospho-(1'-myo-inositol) (ammonium salt) (DPPI), 1,1',2,2'-tetraoleoylcardiolipin (TOCL), 1,2-dioleoyl-sn-glycero-3-phosphoethanol (DOPEt), 1,2-dioleoyl-sn-glycero-3-phosphoethanol (DOPEt) (18:0 The composite membrane according to any one of claims 22 to 29, wherein the polymer is selected from the group consisting of PEG-100, ...

31. 31. The composite membrane of any one of claims 22 to 30, wherein the phospholipid is selected from the group consisting of 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC), 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE), 1,2-dioleoyl-sn-glycero-3-phospho-rac-(1-glycerol) (DOPG), L-α-phosphatidylcholine (egg PC), 1,2-ditetradecanoyl-sn-glycero-3-phosphocholine (DMPC), 2-oleoyl-1-palmitoyl-sn-glycero-3-phosphocholine (POPC), and mixtures thereof.

32. The phospholipid has the formula (I): 【Transformation 3】 (In the formula, R １ represents a saturated or unsaturated aliphatic group having 14 to 24 carbon atoms, R ２ represents a saturated or unsaturated aliphatic group having 14 to 24 carbon atoms, R ３ teeth, 【Chemistry 4】 32. The composite membrane of any one of claims 22 to 31, wherein

33. 33. The composite membrane of any one of claims 24 to 32, wherein the polyamine comprises at least two amine groups, which are independently primary amine groups or secondary amine groups.

34. 34. The composite membrane of claim 33, wherein the polyamine is selected from the group consisting of m-phenylenediamine (MPD), m-phenylenediamine-4-methyl, 1,3-cyclohexanebis(methylamine), o-phenylenediamine (OPD), piperazine, p-phenylenediamine (PPD), 1,1'-biphenyl-4,4'-diamine (benzidine), polyethyleneimine, and mixtures thereof.

35. 25. The composite membrane of claim 24, wherein the monomer comprising at least one crosslinking group is selected from the group consisting of trimesoyl chloride (1,3,5-benzenetricarbonyl trichloride), terephthalic acid chloride, isophthalic acid chloride, biphenyldicarboxylic acid chloride, naphthalenedicarboxylic acid dichloride, biphenyl-4,4'-disulfonyl chloride, 1,3,6-naphthalenetrisulfonyl chloride, and mixtures thereof.

36. 25. The composite membrane of claim 24, wherein the organic phase further comprises an organic solvent that does not react with the monomer comprising at least one crosslinking group.

37. 25. The composite membrane of claim 24, wherein the organic phase comprises the monomer comprising at least one crosslinking group at a concentration of 0.00001% to 2% by weight.

38. 25. The composite membrane of claim 24, wherein the organic phase comprises the monomer comprising at least one crosslinking group at a concentration of 0.001% to 1% by weight.

39. 39. The composite membrane of any one of claims 24 to 38, wherein the surface of the porous membrane substrate is first impregnated with the aqueous phase comprising the polyamine and the phospholipid, and then the impregnated porous membrane substrate is contacted with the organic phase, thereby resulting in interfacial polymerization.

40. 40. The composite membrane of any one of claims 22 to 39, wherein the porous membrane substrate comprises polyethersulfone, polyetherimide, polysulfone, polyacrylonitrile, polyimide, polyvinylidene fluoride, polypropylene, poly(tetrafluoroethylene), or copolymers thereof.

41. 41. The composite membrane of any one of claims 22 to 40, wherein the polyamide layer is free of transmembrane proteins.

42. 42. The composite membrane of claim 41, wherein the polyamide layer does not contain an aquaporin.

43. 43. The composite membrane of any one of claims 22 to 42, wherein the polyamide layer is a wholly aromatic polyamide layer having a thickness of 200 nm to 4000 nm, or the polyamide layer is a semi-aromatic polyamide layer having a thickness of less than 100 nm.

44. A hollow fiber membrane comprising the composite membrane of any one of claims 22 to 43.

45. A flat membrane comprising a composite membrane described in any one of claims 22 to 43.

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