Hydrophilic grafting of a stable crystalline framework layer on a polymer film, method of preparation and use thereof

Abstract

A water permeable coated substrate is disclosed comprising a polymeric substrate in contact with a coating layer, the coating layer comprising a plurality of particles and a crosslinked polymer. Use of the coated substrate, in particular for filtering water, is also disclosed.

Description

[0001] Cross-references to related applications

[0002] This application claims priority to U.S. Provisional Patent Application No. 63 / 193,077, filed May 26, 2021. The contents of the foregoing are incorporated herein by reference in their entirety, as if fully set forth herein. Technical Field

[0003] In some embodiments, the present invention relates to coated hydrophilic polymer substrates and their use, for example, in filter membranes. Background Technology

[0004] Produced water (PW) is a significant byproduct of oil and gas extraction. PW typically contains both organic and inorganic components and is harmful to the environment. Therefore, it must be treated efficiently and economically to minimize environmental damage before being discharged, or it should be recycled as non-potable water for industrial or agricultural uses, especially in water-scarce regions.

[0005] Surface modification is preferred to mitigate membrane fouling in PW treatment because it is easy to process and has negligible environmental impact. It improves the water flux and oil rejection efficiency of the resulting membrane.

[0006] Practical industrial applications of membranes for PW (Potentially Filtrate) treatment require membranes with excellent performance and stability. Therefore, there is a need to develop membranes with superior antifouling properties that provide filtration while maintaining high water flux and oil rejection efficiency. Various crystalline framework nanoparticles, such as ZIF-8 nanoparticles, have recently emerged as promising functional materials for modifying membrane surface properties for water treatment applications due to their unique framework structure, ultra-high specific surface area, tunable size, thermal and chemical stability, ease of synthesis, and low production cost. However, integrating crystalline framework nanoparticles into polymer membranes is challenging because of the limited stability of these nanoparticles as a separation layer during filtration. Therefore, there is a need for a hydrophilic membrane modified with crystalline framework nanoparticles that exhibits antifouling properties, high water flux, and high oil rejection efficiency during PW effluent filtration. Summary of the Invention

[0007] In some embodiments of the present invention, a hydrophilic polymer substrate in contact with a composite coating comprising a plurality of crystalline framework nano or micro particles and cross-linked polymers is described, and its use for, for example, a filter membrane.

[0008] According to one aspect of some embodiments of the present invention, a membrane is provided comprising a polymer membrane in contact with a coating comprising a plurality of crystal framework structures (CFS) and a hydrogel comprising a crosslinked hydrophilic polymer; the membrane is water-permeable.

[0009] In one embodiment, the crosslinked hydrophilic polymer includes a polymer selected from polyacrylates or polymethacrylates.

[0010] In one implementation, CFS comprises nanoparticles.

[0011] In one embodiment, the nanoparticles are selected from covalent organic framework (COF) nanoparticles and metal-organic framework (MOF) nanoparticles.

[0012] In one embodiment, the outer surface of the polymer film is chemically modified.

[0013] In one embodiment, chemical modification is carried out through a plurality of surface groups selected from amino and carboxyl groups.

[0014] In one embodiment, the polymethacrylate comprises poly(2-(N-3-sulfopropyl-N,N-dimethylammonium)methacrylate).

[0015] In one embodiment, the crosslinked hydrophilic polymer is characterized by a crosslinking degree of about 5%.

[0016] In one embodiment, the membrane is characterized by any of the following: (i) a water contact angle of about 7°, (ii) a water contact angle of about 21°, (iii) a water contact angle of less than 51°, or (iv) a water contact angle smaller than that of the original polymer membrane.

[0017] In one embodiment, the membrane is characterized by having a water contact angle that is about 13% smaller than that of the original polymer membrane.

[0018] In one embodiment, the membrane is characterized by any of the following: a pure water flow rate of approximately 450 L / m³. -2 h -1 -bar -1 The flux; the flux recovery rate is approximately 99% or any combination thereof.

[0019] In one embodiment, the polymer membrane is selected from ultrafiltration membranes, nanofiltration membranes, and microfiltration membranes.

[0020] In another aspect, a coating substrate is provided, comprising: a polymer substrate in contact with a coating comprising a plurality of particles and a crosslinked polymer; wherein the crosslinked polymer is a hydrophilic polymer comprising acrylate polymers; the outer surface of the coating is characterized in that the water contact angle is less than about 70°; the crosslinked polymer is characterized in that the degree of crosslinking is between 1% and 20%; the plurality of particles are characterized in that the average particle size is between 1 nm and 20 μm; and the coating substrate is water-permeable.

[0021] In one embodiment, the crosslinked polymer is in the form of a matrix, wherein a plurality of particles are embedded within the matrix or coated by the matrix.

[0022] In one embodiment, the crosslinked polymer is characterized by a degree of crosslinking between 2% and 10%.

[0023] In one embodiment, the polymer substrate is in the form of a porous, water-permeable membrane.

[0024] In one embodiment, the permeable portion includes enough to support a pure water flow rate of at least 10 L*m. -2 h -1 -bar -1 The porosity of the flux.

[0025] In one embodiment, the porous permeable membrane is characterized by an average pore size between 1 and 10 μm.

[0026] In one embodiment, the coating is in the form of a continuous layer, characterized by a dry thickness between 50 nm and 20 μm.

[0027] In one embodiment, the outer surface of the coating is characterized by a negative zeta potential.

[0028] In one embodiment, the outer surface of the coating is characterized by a surface roughness between 10 and 40 nm.

[0029] In one embodiment, the weight ratio (w / w) between the particles in the coating and the crosslinked polymer is between 1:10 and 10:1.

[0030] In one embodiment, the polymer substrate comprises a surface-modified thermoplastic polymer.

[0031] In one embodiment, the surface-modified polymer is characterized by having a water contact angle reduced by at least 10° compared to a similar polymer substrate containing the original thermoplastic polymer.

[0032] In one embodiment, the surface-modified polymer is characterized by a water contact angle of less than 70°.

[0033] In one embodiment, the thermoplastic polymer is selected from: polyacrylonitrile, polyethersulfone, polysulfone, cellulose acetate, polyvinylidene fluoride, polybenzimidazole, inherently microporous polymers, and polyolefins, including any combination thereof and any copolymer thereof.

[0034] In one embodiment, the outer surface of the coating is characterized by a water contact angle between about 5° and about 50°.

[0035] In one implementation, the particles are crystal framework (CFS) particles.

[0036] In one embodiment, the CFS particles include zeolites, metal-organic frameworks (MOFs), and covalent organic frameworks (COFs).

[0037] In one embodiment, the coated outer surface is characterized by reduced microbial adhesion compared to a similar substrate without a coating.

[0038] In one implementation, at least 90% of the outer surface is in contact with the coating.

[0039] In another aspect, a film comprising the coating substrate of the present invention is provided.

[0040] In one embodiment, the water filtration membrane is characterized by a thickness between 10 and 1000 μm.

[0041] In one embodiment, the membrane is characterized by a pore size between 2 nm and 100 nm, optionally wherein the membrane is an ultrafiltration membrane.

[0042] In one embodiment, the membrane is characterized by a flux recovery rate of at least 70%.

[0043] In one embodiment, the membrane is characterized by an oil rejection rate of at least 95%.

[0044] In one embodiment, after continuous water treatment cycles, the membrane retains at least 90% of the initial particle content.

[0045] Unless otherwise defined, all technical and / or scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. While methods and materials similar to or equivalent to those described herein may be used in the practice or testing of embodiments of the invention, exemplary methods and / or materials are described below. In case of conflict, the patent specification (including definitions) shall prevail. Furthermore, materials, methods, and examples are illustrative only and are not intended to be necessarily limiting. Attached Figure Description

[0046] This document describes some embodiments of the invention by way of example only, with reference to the accompanying drawings. Now, detailed reference will be made to the drawings, emphasizing that the details shown are merely examples and are used to illustrate embodiments of the invention. In this regard, those skilled in the art will understand how to practice embodiments of the invention from the description in conjunction with the accompanying drawings.

[0047] In the attached diagram:

[0048] Figure 1 This is a schematic diagram representing a dead-end filtration device. Here, 1: pressure regulator, 2: pressure gauge, 3: stirring tank, 4: membrane with carrier, 5: magnetic stirrer, and 6: permeate collection container.

[0049] Figure 2 Here is a schematic diagram representing the preparation of a water-stable ZIF-8 modified PAN membrane: (1) Hydrolysis to obtain a hydrolyzed PAN membrane (Hy); (2) In-situ growth of ZIF-8 nanoparticles on the Hy membrane to obtain a HyZif membrane; (3) Redox grafting of SBMA / MBA onto the Hy and HyZif membranes to obtain HyG and HyZifG membranes, respectively.

[0050] Figure 3A -B represents the FTIR spectrum of the membrane of this invention. Figure 3A ); and the XPS broadband spectrum of the test film ( Figure 3B The image shows a diagram. The presence of characteristic functional groups on the membrane confirms the modification.

[0051] Figure 4A -B indicates that the membrane of this invention ( Figure 4A ) and ZIF-8 nanoparticles ( Figure 4B The XRD spectrum of ZIF-8 particles is shown in the correlation spectra of HyZif and HyZifG films. Characteristic peaks of ZIF-8 particles are displayed in the correlation spectra of the HyZif and HyZifG films. Figure 4A ).

[0052] Figure 5A -B represents the cross-section of the HyZifG membrane. Figure 5A ) and surface ( Figure 5B The image of the EDX element plot on the film, and the appearance of the Zn element plot, confirms the presence of ZIF-8 nanoparticles on the film.

[0053] Figure 6 A bar chart showing the water contact angle values ​​measured on the dry film using the seat drop method.

[0054] Figure 7A -B is an AFM photomicrograph. Figure 7A ) and a histogram representing the surface roughness of the film as measured by AFM ( Figure 7B The RRMS value is provided next to each membrane name. The scan area is 5 × 5 μm. At least three readings were measured for each membrane to report the RRMS value as the mean ± SD. Figure 7A An AFM micrograph of an exemplary HyZifG membrane with an RRMS value of 24.6 ± 2.0 nm is presented.

[0055] Figure 8 This is a bar chart showing the pure water permeability of the prepared membrane. Compared to the original PAN membrane, the modified membrane recorded a higher permeability value.

[0056] Figure 9This graph shows antifouling filtration experiments conducted on PAN, Hy, HyG, and HyZifG membranes using simulated oilfield PW (see solution composition in Table 1). By adjusting the transmembrane pressure (0.1–0.3 bar), the experiments were conducted at a stable initial flux (100 L·m⁻¹). -2 ·h -1 The tests were conducted under the following conditions. The average transmembrane pressures (in bar) for the different membranes were 0.25 (PAN), 0.18 (Hy), 0.15 (HyG), and 0.22 (HyZifG), respectively. In this paper, W represents the water filtration step, and PW represents the simulated oilfield PW filtration step.

[0057] Figure 10 This is a diagram illustrating the antifouling mechanism of HyZifG membranes in oilfield PW treatment. The inset shows a proposed structure that achieves the chemical stability of the ZIF-8 layer through coordination interactions between negatively charged sulfonic acid groups and positively charged ZIF-8 nanoparticles.

[0058] Figure 11A -D and Figure 11A1 -D1 are SEM micrographs of PAN(11A, 11A1), Hy(11C, 11C1), HyG(11A, 11A1), and HyZifG(11D, 11D1) membranes before and after contamination in oilfield PW treatment. Figure 11A , 11B Images 11C and 11D present SEM micrographs of PAN, Hy, HyG, and HyZifG membranes before fouling. Figure 11A1 , 11B1 Figures 11C1 and 11D1 present SEM micrographs of PAN, Hy, HyG, and HyZifG membranes after fouling. The HyZifG membrane shows negligible contaminant adhesion on its surface, while the original PAN membrane shows significantly higher contaminant adhesion. The results support the good antifouling performance of the HyZifG membrane. Scale bars in all figures represent 5 μm.

[0059] Figure 12 This is a graph showing the FTIR spectra of fresh and (after contamination experiments) used HyZifG membranes, demonstrating the stability of the modified layer on the membrane surface.

[0060] Figure 13 This is a graph showing the zeta potential analysis of PAN, Hy, and HyG films (in 1 mM KCl solution).

[0061] Figure 14A -C is PAN ( Figure 14A ), HyZif Figure 14B ) and HyZifG ( Figure 14CSEM micrographs of the membranes disclosed herein show the different surface morphology compared to the original PAN membrane.

[0062] Figure 15A -D is a micrograph, FTIR, and XRD spectrum of the synthesized COF-300 nanoparticles. Figure 15A -B is a SEM image showing the elliptical shape of the COF-300 nanoparticles. Figure 15C This is the FTIR spectrum of COF-300 nanoparticles, at 1625 cm⁻¹. –1 (attributed to imine C=N stretching) and 2926 cm –1 Their characteristic peaks were shown at (attributed to the CH stretching of the olefins by imine), thus confirming their successful synthesis. Figure 15D This is the XRD pattern of COF-300 nanoparticles.

[0063] Figure 16 This is a micrograph showing a SEM image of COF-300 nanoparticles deposited on a hydrolyzed PAN membrane.

[0064] Figure 17 This is a schematic diagram showing the preparation of a hydrogel-stabilized ZIF-67 modified PAN film: (Step 1) Hydrolysis, (Step 2) In-situ growth of ZIF-67 nanoparticles, (Step 3) UV grafting polymerization of SBMA-co-MBA.

[0065] Figure 18 This is a bar graph showing the water droplet contact angles of the original PAN and the modified membrane of the present invention.

[0066] Figure 19A -F is ( Figure 19A )PAN、( Figure 19B Hy、( Figure 19C HyG、( Figure 19D -E)HyZIF67 and ( Figure 19F SEM analysis of the surface morphology of HyZIF67G film.

[0067] Figure 20A -B is a graph showing the antifouling performance of the original PAN, HyG (10min UV), and HyZIF67G membranes, which filter at pH 6.4-6.7. Figure 20A ) and pH 7.2-7.7 ( Figure 20B The concentration of BSA in the synthetic secondary wastewater (SSWW) solution was measured at 100 ppm.

[0068] Figure 21A -B is PAN after BSA / SSWW contamination ( Figure 21A ) and HyZIF67G membrane ( Figure 21BSEM analysis of the surface morphology of the SEM image (as disclosed in Example 4).

[0069] Figure 22 yes Original PAN and Long-term antifouling filtration experiment of HyZIF67G membrane in synthetic secondary wastewater (SSWW) solution for filtering BSA. Detailed Implementation

[0070] In some embodiments, this invention relates to coated polymer substrates comprising a coating of crystalline framework nanoparticles and a hydrophilically crosslinked polymer (e.g., in the form of a hydrogel). Furthermore, in some embodiments, this invention relates to the use of the coated polymer substrates as water filtration membranes.

[0071] Before explaining at least one embodiment of the present invention in detail, it should be understood that the present invention is not necessarily limited to the details set forth in the following description or exemplified by the embodiments. The present invention can have other embodiments or can be practiced or implemented in various ways.

[0072] This invention is based on the understanding that crosslinked hydrophilic acrylate polymers can be used to stably encapsulate crystalline framework structure particles (e.g., COF and / or MOF nanoparticles) to obtain stable composite membranes suitable for water filtration. In some embodiments, the crosslinked hydrophilic acrylate polymer is applied on top of a layer of crystalline framework structure nanoparticles in contact with a polymer substrate (e.g., in the form of a porous polymer membrane). In some embodiments, the coated polymer substrates disclosed herein are characterized by desired intrinsic properties, including but not limited to enhanced or substantially the same hydrophilicity (reflected by the water contact angle), chemical and / or mechanical stability, thermal stability, sufficient water permeability, and significantly reduced fouling compared to uncoated (or pristine) polymer substrates. In some embodiments, the coated polymer substrates disclosed herein are characterized by desired intrinsic properties suitable for their use as membranes (e.g., water filtration membranes).

[0073] As used herein, the term "chemical stability" refers to the property of the disclosed coated polymer substrate to withstand and function under harsh operating and cleaning conditions, such as high back pressure, strong oxidants, alkalis and acids (typically used for cleaning industrial filter membranes), high density of microorganisms (e.g., biological contaminants), or properties related to thermal stability, high temperatures.

[0074] According to one aspect of the invention, a coating substrate is provided, comprising a polymer substrate in contact with a coating; the coating comprises a plurality of particles and a crosslinked polymer; the crosslinked polymer is a hydrophilic, water-wettable polymer, and is characterized by a degree of crosslinking between 1% and 20%; the plurality of particles are characterized by an average particle size between 1 nm and 20 μm; and wherein the coating substrate is water-permeable.

[0075] In some embodiments, the crosslinked polymer is a hydrophilic polymer characterized by a water contact angle of less than 90°, less than 80°, less than 70°, less than 60°, less than 50°, less than 40°, less than 30°, less than 20°, less than 15°, and any range therebetween. As used herein, the term "water contact angle" for a crosslinked polymer refers to the physical property of the crosslinked polymer surface in the form of a film or a layer deposited on a substrate. The water contact angle of a surface can be determined according to well-known methods, some of which are disclosed in the Examples section below.

[0076] In some embodiments, the crosslinked polymer is derived from a water-soluble monomer. In some embodiments, the crosslinked polymer is derived from a monomer with a water solubility of at least 0.5 g / L, at least 1 g / L, at least 5 g / L, at least 10 g / L, at least 20 g / L, at least 30 g / L, at least 50 g / L, at least 70 g / L, at least 80 g / L, at least 100 g / L, between 1 and 100 g / L, between 10 and 100 g / L, between 10 and 80 g / L, between 10 and 60 g / L, between 20 and 100 g / L, between 20 and 90 g / L, between 20 and 200 g / L, between 10 and 200 g / L, including any range therebetween.

[0077] In some embodiments, the crosslinked polymer comprises a hydrophilic thermoplastic polymer crosslinked by a crosslinking agent. In some embodiments, the crosslinked polymer is in the form of a hydrogel. In some embodiments, the hydrogel comprises a surface-grafted polymer (e.g., a surface-grafted hydrophilic thermoplastic polymer). In some embodiments, the crosslinked polymer is a hydrogel-forming polymer. In some embodiments, the crosslinked polymer is a grafted hydrophilic thermoplastic polymer. In some embodiments, the crosslinked polymer is a grafted polyacrylate. In some embodiments, the hydrophilic thermoplastic polymer comprises an acrylate polymer, including any salts and copolymers thereof. In some embodiments, the hydrophilic thermoplastic polymer is substantially free of polyamino acids and / or polydopamine. In some embodiments, the hydrophilic thermoplastic polymer is primarily composed of an acrylate polymer, including any salts and copolymers thereof.

[0078] In some embodiments, the term "hydrogel" as used herein refers to a non-Newtonian fluid (or semi-solid) comprising a supramolecular structure of cross-linked polymer molecules (e.g., hydrophilic polymers such as polyacrylates or polymethacrylates) and water. In some embodiments, the supramolecular structure is physically bonded to water molecules. In some embodiments, the supramolecular structure is a three-dimensional network of cross-linked polymer chains.

[0079] In some embodiments, the hydrogel or polymer matrix disclosed herein is substantially free of fibers (e.g., CNT fibers, electrospun fibers, polymer fibers, etc.). In some embodiments, the hydrogel or polymer matrix is ​​characterized by a periodic structure. In some embodiments, the hydrogel or polymer matrix has an ordered structure comprising polymer chains distributed therein in a patterned manner (e.g., the entire hydrogel or polymer matrix is ​​characterized by a defined periodic pattern of polymer chains). In some embodiments, the pattern comprises a network. In some embodiments, the polymer chains form a network within the hydrogel or polymer matrix. In some embodiments, the network is characterized by (i) substantially uniform pore size (e.g., the average distance between two adjacent polymer chains); (ii) substantially uniform pore density or distribution pattern within the hydrogel or polymer matrix; or both (i) and (ii).

[0080] In some embodiments, the acrylate polymer includes polyacrylates, esters thereof, alkylated polyacrylates (e.g., polymethacrylate), polyacrylamide, including any copolymers or mixtures thereof. Various acrylate polymers are known in the art. In some embodiments, the acrylate polymer is or includes a graft polymer. In some embodiments, the acrylate polymer is or includes an in-situ graft polymer.

[0081] In some embodiments, the term "acrylate polymer" as defined below refers to a non-crosslinked polymer. In some embodiments, acrylate polymers are represented by Formula 1:

[0082] Where n represents an integer; X represents O, OH, N, NH, or NH2, depending on the valence; R1 and R are either independently absent or represent H or a substituent selected from: alkyl (straight-chain or branched), hydroxyalkyl, haloalkyl, aminoalkyl, cycloalkyl, ethylene glycol, polyethylene oxide, dimethylaminoethyl, trimethylaminoethyl, dimethylaminoethyl-3-sulfopropyl, cyano, nitro, carboxyl, hydroxy, halogen, amino, or any combination thereof. In some embodiments, n represents an integer between 2 and 100,000, including any range therebetween.

[0083] In some embodiments, the acrylate polymers are uncharged polymers. In some embodiments, the acrylate polymers are ionizable polymers (e.g., capable of protonation or deprotonation in water, thereby producing positively or negatively charged polymers, for example, in a pH range of 5 to 8). In some embodiments, the acrylate polymers are inherently charged polymers (e.g., negatively and / or positively charged polymers). In some embodiments, the acrylate polymers are zwitterions.

[0084] In some embodiments, the acrylate polymer is poly(2-(N-3-sulfopropyl-N,N-dimethylammonium) ethyl methacrylate), including any salt or copolymer thereof.

[0085] In some embodiments, the crosslinked polymer is characterized by a degree of crosslinking ranging from 1% to 20%, 1% to 10%, 1% to 8%, 1% to 7%, 2% to 20%, 2% to 10%, 2% to 8%, 1% to 6%, 1% to 5%, 1% to 4.5%, 2% to 5%, 1% to 2.5%, 2.8% to 20%, 2.8% to 10%, 5% to 20%, 5% to 10%, 5.5% to 20%, 5.5% to 10%, 5.5% to 8%, and any range therein. In some embodiments, as disclosed herein, the degree of crosslinking is chosen to obtain a network capable of retaining particles within the coating and to make the coated substrate permeable. Without being bound by any particular theory, it is assumed that a crosslinking degree of 10% or 20% or higher would significantly reduce the permeability of the coated substrate, thus making it less suitable for use as a membrane.

[0086] In some embodiments, the crosslinked polymer comprises a plurality of polymer chains covalently bonded to each other by a crosslinking agent. In some embodiments, the polymer chains comprise thermoplastic polymer chains (also referred to herein as "thermoplastic polymer"). In some embodiments, the crosslinked polymer is in the form of a polymer matrix. In some embodiments, the polymer matrix is ​​an interwoven matrix composed of randomly distributed polymer chains. In some embodiments, the polymer chains are randomly distributed within the matrix. In some embodiments, the matrix is ​​substantially free of aligned or oriented polymer chains. In some embodiments, the matrix is ​​substantially free of polymer chains aligned or oriented in a particular direction. In some embodiments, the thermoplastic polymers constituting the polymer matrix are chemically identical polymers. In some embodiments, the polymer matrix comprises a variety of chemically different polymers. In some embodiments, the polymer matrix comprises a mixture of chemically different polymer species. In some embodiments, the polymer matrix is ​​in the form of a hydrogel containing water molecules bonded to the polymer chains. In some embodiments, the polymer matrix is ​​water-absorbing. In some embodiments, the polymer matrix is ​​swellable. In some embodiments, the coating described herein is capable of absorbing 10% to 1000%, 10% to 100%, 50% to 1000%, 100% to 1000%, 10% to 500% of the initial dry weight of the coating substrate of the present invention, including any range therebetween.

[0087] In some embodiments, the crosslinking agent is or includes a bifunctional molecule (e.g., a diacrylate) capable of reacting with monomers (and / or with propagating polymer chains) to covalently crosslink the polymer chains. Those skilled in the art will understand that, after crosslinking, the crosslinking agent undergoes chemical modification. Therefore, the crosslinked polymer comprises polymer chains covalently bonded by a chemically modified (or derivatized) crosslinking agent. A non-limiting example of a crosslinking agent is N'-methylenebisacrylamide.

[0088] In some embodiments, polymer chains contact the particles described herein to form a coating. In some embodiments, the coating is in the form of a layer. In some embodiments, the coating is in the form of a single layer or multiple different layers. In some embodiments, one or more layers of the coating independently comprise a crosslinked polymer and the particles described herein. In some embodiments, one or more layers of the coating are in the form of a composite material.

[0089] In some embodiments, the particles are embedded within a polymer matrix. In some embodiments, the particles are uniformly distributed within the polymer matrix. In some embodiments, the particles are encapsulated by the polymer matrix. In some embodiments, the particles are physically and / or chemically adsorbed onto or within the polymer matrix.

[0090] In some embodiments, the particles are in the form of a first layer, and the polymer matrix is ​​in the form of a second layer. In some embodiments, the first layer is located on top and bonded to the substrate. In some embodiments, the first layer and / or coating substantially cover at least one surface of the substrate. In some embodiments, substantial coverage includes at least 80%, at least 90%, at least 95%, at least 97%, at least 99%, or at least 99.9% surface coverage of the substrate, including any range therebetween.

[0091] In some embodiments, the second layer is located on top and bonded to the first layer. In some embodiments, the second layer is located on top of the first layer in the form of a coating. In some embodiments, the second layer reinforces the first layer. In some embodiments, the second layer stabilizes the first layer. In some embodiments, the second layer prevents the decomposition of the first layer. In some embodiments, the second layer prevents the separation of the first layer from the substrate. In some embodiments, the second layer stabilizes the first layer. In some embodiments, the second layer (or crosslinked polymer) provides sufficient physical stability to the particles for use with the coated substrate as a filter membrane (e.g., a water filter membrane or a UF membrane). In some embodiments, the second layer (or crosslinked polymer) provides sufficient physical stability to the coated substrate (e.g., by substantially preventing the decomposition of the coating and / or leakage of particles therefrom), wherein the physical stability is sufficient to enable the coated substrate to function as a membrane. In some embodiments, the physical stability is sufficient to support 10 to 1000 L·m -2 ·h -1 ·bar -1 100 to 1000 L·m -2 ·h -1 ·bar -1 100 to 2000 L·m -2 ·h -1 ·bar -1 The water flux within the range, including any range in between. In some embodiments, the coating and the substrate are permeable. In some embodiments, the coated substrate is configured to support 10 to 1000 L·m. -2 ·h -1 ·bar -1 100 to 1000 L·m -2 ·h -1 ·bar -1 100 to 2000 L·m -2 ·h -1 ·bar -1 The water flux within the range, including any range in between.

[0092] In some embodiments, the crosslinked polymer (or second layer) provides barrier properties to the coated substrate, thereby significantly improving its stability. In some embodiments, the crosslinked polymer (or second layer) provides barrier properties to substantially maintain coating integrity. In some embodiments, the crosslinked polymer (or second layer) provides barrier properties to substantially prevent particle leakage therefrom. In some embodiments, the stable coated substrate exhibits substantially no coating decomposition and / or substantially retains the initial particle content within the coating. In some embodiments, the crosslinked polymer (or second layer) substantially retains the initial particle content within the coating. In some embodiments, the physical stability is sufficient to retain at least 80%, at least 90%, at least 95%, at least 97%, or at least 99% of the initial particle content within the coating after consecutive (e.g., at least 2, at least 3, at least 5, at least 10, at least 20, at least 50, at least 100) filtration cycles. Coating integrity is assessed by determining the concentration of particulate components in the filtrate (e.g., in the case of MOF particles, a significantly increased concentration of metal cations in the filtrate indicates coating instability).

[0093] In some embodiments, the term "bonding" refers to any non-covalent bond or interaction, such as an electrostatic bond, dipole-dipole interaction, van der Waals interaction, ionic interaction, hydrogen bond, hydrophobic interaction, π-π stacking, London force, etc. In some embodiments, the non-covalent bond or interaction is a stable bond or interaction, wherein stability is as described herein.

[0094] In some embodiments, the crosslinked polymer is in the form of a network (e.g., a 2D or 3D network structure). In some embodiments, the network is porous, wherein the average pore size of the network is the same as or smaller than the average size of the particles disclosed herein. In some embodiments, the average pore size of the network is at least 10%, at least 100%, at least 500%, at least 1000%, or at least 10,000% smaller than the average size of the particles, including any range therebetween. In some embodiments, the average pore size of the network is between 1 nm and 1 μm, between 1 and 100 nm, between 5 and 100 nm, between 10 and 100 nm, between 1 and 500 nm, between 10 and 500 nm, or between 100 and 1000 nm, including any range therebetween.

[0095] In some embodiments, the term "porous" as used herein refers to a material characterized by porosity, for example, containing pores, voids, voids, or spaces within its network. However, the porous layer may optionally contain additional material in the spaces between the polymer chains, provided that at least a portion of the void volume is not filled with the additional material. In some embodiments, the additional material includes particles disclosed herein.

[0096] In some implementations, porosity is measured as a fraction between 0 and 1 relative to the volume of the coating consisting of voids (or pores).

[0097] In some embodiments, the porosity of the coating is from 0.1 to 0.99.

[0098] In some embodiments, the porosity of the coating is 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, or 0.99, including any value and range therebetween.

[0099] In some embodiments, the coating is permeable. In some embodiments, the porosity of the coating is sufficient to provide permeability. In some embodiments, the porosity of the coating is sufficient to support the water fluxes disclosed herein.

[0100] The term "porosity" refers to a measurement of the pore space in a material, and in some embodiments, it is defined as the fraction of the free volume or pore volume of a material relative to the total volume of the material, determined by well-known physical measurement methods such as N2 adsorption / desorption.

[0101] In some embodiments, the substrate for coating and / or coating of the present invention is a composite material. In some embodiments, the coating is a solid coating. In some embodiments, the substrate for coating and / or coating of the present invention is in the form of a layered composite material. As used herein, a "composite material" is a material made of two or more component materials having significantly different chemical or physical properties when combined to produce substances having properties different from those of individual elements.

[0102] In some embodiments, a composite material refers to a substantially homogeneous material that cannot be easily separated into individual components (e.g., the particles and crosslinked polymers of the present invention). In some embodiments, the composite material exhibits substantially no phase separation or decomposition (also referred to herein as a "stable" composite material). In some embodiments, the composite material exhibits substantially no multilayer structure. In some embodiments, the coating is a single-layer coating.

[0103] In some embodiments, the term "layer" refers to a substantially uniform thickness of material. In some embodiments, a layer or film comprises a single layer or multiple layers. In some embodiments, the terms layer and film are used interchangeably herein.

[0104] In some embodiments, the coating is in the form of different layers bonded to the substrate. In some embodiments, particles and / or cross-linked polymers are bonded to the substrate. In some embodiments, the particles are bonded to the substrate through electrostatic interactions and / or coordination bonds.

[0105] In some embodiments, the coating thickness is any range within the range of 0.05 μm to 100 μm, 0.1 μm to 100 μm, 0.1 μm to 10 μm, 0.05 μm to 10 μm, 0.5 μm to 100 μm, 0.5 μm to 50 μm, 1 μm to 50 μm, 1 μm to 100 μm, 1 μm to 100 μm, 1 μm to 100 μm, 10 μm to 1000 μm, and 100 μm to 1000 μm. In some embodiments, the coating thickness refers to the dry thickness. In some embodiments, the coating exists as a layer of substantially uniform thickness. In some embodiments, the term "thickness" refers to the median of the shortest distance from one side of the coating to the other (e.g., from the inner surface to the outer surface of the coating). Typically, the thickness is measured in orthogonal directions.

[0106] In some embodiments, the coating comprises an inner surface facing the substrate and an outer surface facing the surrounding environment. In some embodiments, the outer surface of the coating is primarily composed of a cross-linked polymer. In some embodiments, the inner surface of the coating is primarily composed of particles disclosed herein. In some embodiments, the outer surface of the coating is characterized by any one of the following: (i) a negative zeta potential; (ii) a surface roughness between 10 and 40 nm; or both (i) and (ii). In some embodiments, the outer surface of the coating is further characterized by a water contact angle of less than 90°, less than 80°, less than 70°, less than 60°, less than 50°, less than 40°, less than 30°, less than 20°, less than 15°, or any range therein. In some embodiments, the outer surface of the coating is further characterized by a water contact angle between about 5° and about 50°, about 5° and about 60°, about 5° and about 10°, about 10° and about 50°, about 10° and about 40°, about 5° and about 30°, about 5° and about 40°, about 10° and about 30°, and about 30° and about 60°, and any range therein. As used herein, “water contact angle” describes the angle formed by water relative to the outer surface of the coating at the point where the free surface of a stationary liquid contacts the horizontal surface of the coating.

[0107] Typically, but not entirely, to measure the contact angle, a drop of water is formed on the tip of a hypodermic needle attached to a spiral syringe. The syringe is secured to a support, which reduces any irregularities resulting from manual droplet deposition. The substrate is then raised using the Y-control of the stage until it contacts the water droplet. The droplet is then brought into the microscope's field of view and focus by the X-Y translation of the stage, and an image is captured. The contact angle is calculated using methods known in the art.

[0108] In some embodiments, the outer surface of the coating is characterized by a negative zeta potential in the following ranges: between -1 and -60, between -1 and -20, between -5 and -30, between -5 and -20, between -5 and -10, between -10 and -30, between -10 and -60, between -1 and -40, between -1 and -50, between -5 and -50, between -5 and -60, between -5 and -40, between -1 and -20, and between -20 and -30 mV, including any range therebetween (e.g., when measured at pH values ​​between 4 and 9). In some embodiments, the outer surface of the coating is characterized by a larger negative zeta potential compared to the original (uncoated) substrate, wherein the negative zeta potential is at least 1 mV greater, at least 5 mV greater, or at least 10 mV greater, including any range therebetween.

[0109] In some embodiments, the outer surface of the coating is characterized by a surface roughness between 10 and 40 nm, between 10 and 100 nm, between 1 and 40 nm, between 1 and 100 nm, between 1 and 30 nm, between 10 and 20 nm, between 20 and 100 nm, and any range therein.

[0110] The term "roughness" used in this article relates to the irregularity of surface texture. Irregularity refers to the peaks and valleys of a surface.

[0111] In some implementations, roughness values ​​are calculated using AA (arithmetic mean) and RMS (root mean square). The AA method uses the absolute value of the deviation during averaging, while the RMS method uses the squared value of the deviation during averaging.

[0112] In some embodiments, the coating disclosed herein consists primarily of the crosslinked polymer and particles disclosed herein.

[0113] In some embodiments, the weight ratio (w / w) between the particles in the coating and the crosslinked polymer is between 1:10 and 1:10,000; between 1:10 and 10:1; between 1:10 and 1:1000; between 1:10 and 1:100; between 1:1 and 1:100; between 1:10 and 1:50; between 1:50 and 1:1000; between 1:50 and 1:10,000; between 1:100 and 1:1000; between 1:100 and 1:1000. The ranges are: between 10,000, between 100:1 and 1:1, between 50:1 and 1:1, between 10:1 and 1:1, between 80:1 and 1:1, between 80:1 and 10:1, between 100:1 and 10:1, between 100:1 and 20:1, between 100:1 and 50:1, between 50:1 and 30:1, between 30:1 and 10:1, between 10:1 and 5:1, between 5:1 and 1:1, and inclusivity.

[0114] In some embodiments, the w / w concentration of particles in the coated substrate is between 0.001% and 30%, between 0.01% and 30%, between 0.1% and 30%, between 0.1% and 20%, between 0.1% and 10%, between 0.1% and 5%, between 1% and 30%, between 1% and 20%, between 5% and 30%, between 5% and 20%, between 1% and 5%, between 0.5% and 10%, between 0.5% and 20%, between 0.01% and 1%, between 1% and 10%, and any range therein.

[0115] In some embodiments, the particles are porous crystalline particles. In some embodiments, the particles are crystalline framework structures (CFS). In some embodiments, the particles are nanoparticles. In some embodiments, the particles are nanoparticle CFS. In some embodiments, the particles are adsorbents (e.g., nanoparticle adsorbents). In some embodiments, the particles are characterized by having porosity sufficient to absorb water contaminants (e.g., inorganic salts—such as nitrate anions, hydrophobic materials—such as hydrocarbons, organic solvents, oils, etc.). In some embodiments, the particles or CFS comprise metal-organic frameworks (MOFs), covalent organic frameworks (COFs), or any combination thereof. In some embodiments, the CFS is substantially crystalline. In some embodiments, the CFS is substantially free of amorphous particles or amorphous substances. In some embodiments, the CFS is substantially crystalline. In some embodiments, the CFS comprises a metal in a crystalline state. In some embodiments, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, at least 95%, at least 99%, or at least 99.5% of the metal in the CFS by weight (or atomic percentage) is in a crystalline state. In some embodiments, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, at least 95%, at least 99%, and at least 99.5% of the metal in the coated substrate of the present invention, by weight (or atomic percentage), is in a crystalline state. In some embodiments, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, at least 95%, at least 99%, and at least 99.5% of the CFS in the coated substrate of the present invention, by weight (or atomic percentage), is in a crystalline state. In some embodiments, the presence (and / or crystallinity) of particles in the coated substrate can be determined by XRD or FT-IR. Exemplary XRD / FT-IR spectra of the coated substrates are presented herein.

[0116] Exemplary particles include, but are not limited to, COF-102, COF-103, COF-105, COF-108, and COF-300 particles, zeolite imidazole framework (ZIF) particles, such as ZIF-L, ZIF-8, ZIF-67, or any combination thereof. Other porous crystalline particles (such as CFS or any other organic, inorganic, or metal-organic porous crystalline particles) are well known in the art.

[0117] In some embodiments, the particles are characterized by an average particle size between 1 nm and 20 μm, between 1 nm and 10 μm, between 1 nm and 1 μm, between 1 nm and 5 μm, between 10 nm and 20 μm, between 10 nm and 10 μm, between 10 nm and 1 μm, between 10 nm and 5 μm, between 1 nm and 100 nm, between 1 nm and 1000 nm, between 1 nm and 500 nm, between 10 nm and 500 nm, between 500 nm and 20 μm, between 500 nm and 10 μm, between 500 nm and 5 μm, between 500 nm and 3 μm, and any range therein.

[0118] In some embodiments, particles are bonded to a substrate to obtain a dense layer (e.g., a first layer). In some embodiments, the first layer is characterized by a thickness between 100 nm and 10 μm, between 500 nm and 10 μm, between 700 nm and 10 μm, between 1 and 10 μm, between 1 and 5 μm, between 500 nm and 5 μm, between 100 nm and 5 μm, between 100 nm and 1 μm, between 500 nm and 3 μm, and any range therein.

[0119] In some embodiments, the particles are stably bonded to a substrate to form the coating substrate of the present invention, characterized by sufficient stability as described herein. In some embodiments, the particles are in-situ grown particles. In some embodiments, the particles are attached to the substrate via electrostatic bonds, non-covalent bonds, and / or coordination bonds.

[0120] In some embodiments, the particles are stably bonded to the chemically modified substrate. In some embodiments, the substrate is a porous substrate. In some embodiments, the outer surface of the substrate is chemically modified. In some embodiments, the chemical modification includes a variety of surface groups, including carboxyl, amino, amide, hydroxyl, or any combination thereof. In some embodiments, the chemical modification includes ionizable groups, wherein the ionization is as described herein. In some embodiments, the chemical modification provides a negative surface charge to the substrate. In some embodiments, the chemically modified substrate is characterized by having a larger negative zeta potential compared to the original substrate, wherein the larger negative zeta potential is at least 1 mV, at least 5 mV, at least 10 mV, at least 20 mV, at least 30 mV, or any range therein.

[0121] In some embodiments, the chemically modified substrate is characterized by a pH value between 3.5 and 5.5 or an isoelectric point of about 4.

[0122] In some embodiments, chemical modification provides binding affinity to the outer surface of the substrate, wherein the binding affinity is sufficient to promote particle attachment thereto. In some embodiments, the chemically modified substrate is characterized by a significantly enhanced binding affinity to particles compared to the virgin substrate. In some embodiments, the binding affinity of the chemically modified substrate is enhanced by at least 2, 10, 100, 1000, or 10000 times relative to the virgin substrate.

[0123] In some embodiments, the substrate is primarily composed of a thermoplastic polymer. In some embodiments, the substrate includes a hydrophobic polymer. In some embodiments, the thermoplastic polymer is a hydrophobic polymer (e.g., characterized by a water contact angle greater than 90°, or between 90° and 160°). In some embodiments, the thermoplastic polymer is a hydrophilic polymer (e.g., characterized by a water contact angle less than 90°, or between 1° and 90°). In some embodiments, the thermoplastic polymer is selected from fluorinated polymers, such as polyvinylidene fluoride, polysulfone, polyols, polyethersulfone, polyamides, polyesters, cellulose acetate, nitrocellulose, polybenzimidazole, PVP, inherently microporous polymers, polyolefins, including any copolymers thereof, and any mixtures thereof. In some embodiments, the polyolefin includes polyethylene, polypropylene, polymethylpentene (PMP), polybutene-1 (PB-1); ethylene-octene copolymer, stereoblock polypropylene, propylene-butane copolymer, low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), very low-density polyethylene (VLDPE), ultra-low-density polyethylene (ULDPE), medium-density polyethylene (MDPE), high-density polyethylene (HDPE), including any copolymers and mixtures thereof.

[0124] In some embodiments, the polyol includes polyvinyl alcohol (PVA), ethylene-vinyl alcohol copolymer (EVOH), or both.

[0125] Exemplary polymers with inherent microporosity well known in the art include, but are not limited to: PIM-1, PIM-EA-TB, PIM-PY, PIM-EA-TB-H2 and PIM-7 or any combination thereof.

[0126] In some embodiments, the inherently microporous polymer is characterized by a pore size range between about 1 nm and about 10 nm, and / or a surface area between about 700 and 1000 m². 2 g -1 Between, including any range within.

[0127] In some embodiments, the surface-modified substrate is characterized by a water contact angle of less than 90°, less than 80°, less than 70°, less than 60°, less than 50°, less than 40°, less than 30°, less than 20°, less than 15°, between 10 and 90°, between 10 and 70°, between 5 and 70°, between 10 and 60°, between 15 and 60°, between 20 and 60°, between 20 and 70°, between 30 and 70°, between 15 and 40°, between 15 and 50°, between 15 and 30°, and any range thereof.

[0128] In some embodiments, the surface-modified substrate is characterized by a lower water contact angle of at least 5°, at least 10°, at least 20°, or at least 30° compared to the virgin substrate. In some embodiments, the virgin substrate comprises the same thermoplastic polymer, and the outer surface of the virgin substrate is not modified. In some embodiments, the virgin substrate is an unmodified substrate composed essentially of an unmodified (or virgin) thermoplastic polymer.

[0129] In some embodiments, the substrate comprises a hydrophilic thermoplastic polymer selected from polyacrylonitrile, polyethersulfone, nitrocellulose, including any copolymers or mixtures thereof. In some embodiments, the terms "hydrophilic" and "water-wettable" are used interchangeably herein. Other hydrophilic (and / or water-wettable) polymers are well known in the art. In some embodiments, the hydrophilic thermoplastic polymer is characterized by a water contact angle of less than 90°, less than 80°, less than 70°, less than 60°, less than 50°, less than 40°, less than 30°, less than 20°, and any range therein.

[0130] In some embodiments, the substrate is a porous substrate. In some embodiments, the substrate includes a plurality of pores, characterized in that the pore size is 2 to 100 nm, 10 to 100 nm, 5 to 100 nm, 20 to 100 nm, 30 to 100 nm, 2 to 50 nm, 50 to 100 nm, 5 to 80 nm, or any range therein. In some embodiments, the substrate includes a plurality of pores, characterized in that the average pore size is 5 nm to 300 nm, for example, 5 nm, 10 nm, 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, 100 nm, 150 nm, 200 nm, 250 nm, 300 nm, 350 nm, 400 nm, 450 nm, or 500 nm, or any value or range therein.

[0131] In some embodiments, the porosity of the substrate is 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, or 0.99, including any value and range therebetween. In some embodiments, the porous substrate is in the form of a membrane (e.g., a filter membrane or an ultrafiltration membrane) configured to support the water flux described herein.

[0132] In some embodiments, the disclosed coated substrate is characterized by a density of 0.05 g / cm³. 3 Up to 2g / cm 3 Within the range. In some embodiments, the disclosed coated substrate is characterized by a density of 0.1 g / cm³. 3 Up to 1g / cm 3 Within the range. In some embodiments, the disclosed coated substrate is characterized by a density of 0.2 g / cm³. 3 Up to 0.8 g / cm 3 Within the range.

[0133] In some embodiments, the disclosed coating substrate is characterized by a density of 0.05 g / cm³. 3 0.1g / cm 3 0.2g / cm 3 0.3g / cm 3 0.4g / cm 3 0.5g / cm 3 0.6g / cm 3 0.7g / cm 3 0.8g / cm 3 0.9g / cm 3 1g / cm 3 1.1g / cm 3 1.2g / cm 3 1.3g / cm 3 1.4g / cm 3 1.5g / cm 3 1.6g / cm 3 1.7g / cm 3 1.8g / cm 3 1.9g / cm 3 or 2g / cm 3 This includes any values ​​and ranges within it.

[0134] In some embodiments, the disclosed coated substrate is characterized in that its mechanical strength, thermal stability, and / or water permeability are substantially the same as those of the original substrate. In some embodiments, the water permeability of the coated substrate is reduced relative to the original substrate by the following ranges: 10% to 70%, 10% to 50%, 10% to 30%, 10% to 20%, and any values ​​and ranges therein.

[0135] As used in this article, the term "mechanical strength" refers to overall and desired strength, such as fracture strength, stiffness, flexibility, and / or toughness.

[0136] In some embodiments, the thermal stability of the coated substrate is predetermined by the melting points of the substrate and the crosslinked polymer. In some embodiments, the coated substrate exhibits thermal stability up to, for example, at least about 100°C, at least 150°C, up to about 200°C, up to about 300°C, or up to about 400°C, including any values ​​and ranges therein.

[0137] membrane

[0138] In another aspect, an article of article comprising a substrate coated herein is provided. Exemplary articles of article include, but are not limited to, agricultural equipment, containers, various agricultural equipment, building components, water treatment equipment and components thereof, organic waste treatment equipment and components thereof, microelectronic equipment, microelectromechanical devices, photovoltaic equipment, or microfluidic devices.

[0139] In some embodiments, the article is a filter membrane.

[0140] In some embodiments, the article is a water filtration membrane as defined herein, used for the selective separation of chemical species (e.g., nitrates and / or organic lipophilic molecules, such as organic solvents, oils, hydrocarbons, etc.), particularly for the selective purification of contaminated water (e.g., produced water).

[0141] As shown in the Examples section below, the filtration membrane exhibits improved oil retention and flux recovery compared to the original membrane. Furthermore, the exemplary membrane of this invention shows virtually no biofouling after prolonged operation.

[0142] In some embodiments, the disclosed membrane does not have an additional polymer layer (such as a polymer on top of the outer surface of the carrier substrate or coating).

[0143] In some implementations, the membrane can withstand a certain degree of applied pressure or force, as described below.

[0144] In some embodiments, the term "filtration membrane" as used herein refers to a membrane characterized by its molecular weight cutoff value and / or retention value for inorganic salts and / or small organic molecules.

[0145] In some embodiments, the molecular weight cutoff value of the membrane is about 2 kDa, about 10 kDa, about 50 kDa, about 100 kDa, about 150 kDa, about 160 kDa, about 170 kDa, about 180 kDa, about 190 kDa, about 200 kDa, about 250 kDa, about 300 kDa, about 340 kDa, about 350 kDa, about 400 kDa, between about 2 and about 300 kDa, between about 2 and about 200 kDa, and any range therein.

[0146] In some embodiments, the disclosed membrane is a microfiltration, ultrafiltration, or nanofiltration membrane. As further demonstrated in the Examples section below, the unique morphology and composition of the disclosed membrane (e.g., the substrate coated according to the present invention) can promote high membrane permeability. Specifically, the inventors have successfully implemented the disclosed coatings on ultrafiltration membranes, as exemplified in the Examples section. Therefore, it is contemplated that the disclosed coatings are suitable for application on polymer ultrafiltration membranes, and further suitable for application on nanofiltration membranes, and selectively suitable for application on microfiltration membranes.

[0147] In some implementations, "high permeation rate" means a permeation rate of at least about 10 to at least about 600 L / m² per bar applied. 2 h, or approximately 10 to 600 L / m per bar applied. 2 h, or approximately 30 to 600 L / m per bar applied. 2 h, for example, the applied dose is at least about 10 L / m 2 h, the applied bar is at least about 30 L / m 2 h, the applied bar is at least about 60 L / m 2 h, the applied bar is at least about 100 L / m 2 h, the applied amount is at least approximately 150 L / m 2 h, the applied amount is at least about 200 L / m 2 h, the applied amount is at least approximately 250 L / m 2 h, the applied bar is at least about 300 L / m 2 h, the applied bar is at least about 350 L / m 2 h, the applied dose is at least approximately 400 L / m²h, the applied dose is at least approximately 450 L / m²h. 2 h, the applied amount is at least about 500 L / m 2 h, the applied bar is at least about 448 L / m 2 The permeability of h, including any range therein.

[0148] In some embodiments, the disclosed membrane is characterized by having substantially the same or increased permeability compared to a primary membrane (e.g., a similar membrane without coating). In some embodiments, the disclosed membrane is characterized by increased permeability compared to a primary membrane, wherein the increase is about 5%, about 10%, about 13%, about 15%, about 20%, about 30%, about 40%, about 50%, or any range therein.

[0149] In some embodiments, the disclosed membrane is a water filtration membrane, characterized by a thickness between 50 and 1000 μm, between 50 and 200 μm, between 200 and 500 μm, between 200 and 1000 μm, between 10 and 100 μm, between 10 and 100 μm, between 1 and 1000 μm, between 1 and 100 μm, between 10 and 500 μm, between 100 and 1000 μm, between 100 and 500 μm, between 500 and 1000 μm, and any range thereof.

[0150] In some embodiments, the disclosed membrane is an ultrafiltration membrane, characterized by a pore size between 2 and 100 nm, between 10 and 100 nm, between 5 and 100 nm, between 20 and 100 nm, between 30 and 100 nm, between 2 and 50 nm, between 50 and 100 nm, between 5 and 80 nm, and any range therein.

[0151] In some embodiments, the disclosed membrane is characterized by a flux recovery rate of at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, at least 97%, at least 98%, at least 98.5%, at least 99%, 70% to 95%, 70% to 99%, 70% to 98.5%, and any range therein.

[0152] In some embodiments, the disclosed membrane is characterized by an oil rejection rate of at least 50%, at least 60%, at least 70%, at least 75%, at least 80%, at least 90%, at least 93%, at least 95%, at least 96%, at least 97%, at least 99%, at least 98%, at least 99.5%, at least 99.7%, at least 99.9%, or at least 99.99%, including any range therein.

[0153] In some embodiments, the disclosed membrane is stable when exposed to any of the following (e.g., substantially retains its initial particle content, the coating substantially does not decompose or separate from the substrate, there is no contamination, and substantially retains any of the following: size, porosity, permeability, physical properties such as elasticity, selectivity, oil retention): continuous water treatment cycles (e.g., 2, 3, 5, 7, 10, 20, 50, 100, between 2 and 100, between 2 and 10, between 2 and 20, between 2 and 50, and any range therein); temperatures up to 300°C, up to 200°C, up to 150°C, up to 100°C, or between -30 and 200°C, between 0 and 200°C, between -30 and 300°C, between -30 and 150°C, between 0 and 300°C, and any range or value therein). In some embodiments, the term "stable" refers to the membrane's ability to maintain its structural, physical-mechanical, and / or chemical integrity. In some implementations, a membrane is said to be stable if it does not decompose and / or dissociate substantially, as is described herein.

[0154] In studying the activity of the membrane disclosed herein, the inventors unexpectedly discovered that the membrane exhibits high antifouling activity, and therefore can be advantageously incorporated into filtration systems that require such activity.

[0155] In this document, “anti-biofouling activity” or “antifouling activity” refers to the ability to inhibit (prevent), reduce or delay biofilm formation or microbial adhesion to the outer surface of a coated substrate (e.g., the membrane disclosed herein).

[0156] As used in this article, the term "biofilm" refers to an aggregate of living cells that adhere to each other and / or are fixed to a surface as colonies. Cells are often embedded in an extracellular polymeric substance (EPS) autocrine matrix—also known as "mucus"—a polymeric, viscous mixture of nucleic acids, proteins, and polysaccharides.

[0157] In the context of this embodiment, the living cells that form biofilms can be cells of single-celled microorganisms (prokaryotes, archaea, bacteria, eukaryotes, protists, fungi, algae, Euglena, protozoa, dinoflagellates, apical complexes, trypanosomes, amoebas, etc.), or cells of multicellular organisms where biofilms can be considered as cell communities (similar to the case of single-celled organisms), or lower forms of tissues.

[0158] In the context of this embodiment, the cells originate from microorganisms, and the biofilm is a biofilm of microorganisms (such as bacteria and fungi). Microbial cells growing in a biofilm are physiologically distinct from the "planktonic form" of cells in the same organism; in contrast, the planktonic form is a single cell that can float or swim in a liquid medium. Biofilms can undergo several life cycle steps, including initial attachment, irreversible attachment, one or more maturation stages, and dispersion. The phrase "anti-biofilm formation activity" refers to the ability of a substance to influence the prevention of biofilm formation by bacteria, fungi, and / or other cells, and / or to influence the rate at which biofilms of bacteria, fungi, and / or other cells accumulate on the membrane surface.

[0159] In some embodiments, the biofilm comprises bacterial cells. In some embodiments, the bacterial cells have bacteria selected from all Gram-positive and Gram-negative bacteria.

[0160] In some embodiments, the Gram-negative biofilm-forming bacteria may be selected from the following group of species, such as, but not limited to, Proteus, Enterobacter, Citrobacter, Shigella, Escherichia, Edwardsiella, Aeromonas, Orthomonas, Moraxella, Alcaligenes, and Pseudomonas.

[0161] As shown below, the membranes described herein exhibit anti-biofilm activity, thus preventing, delaying, or reducing biofilm formation or biofilm quality. Therefore, the membranes described herein can be effectively incorporated into filtration systems containing them, where anti-biofilm formation activity is beneficial (e.g., necessary or desirable).

[0162] As used herein, in the context of biofilm formation, the term “prevent” means that biofilm formation is substantially eliminated or reduced by at least 20%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, or at least 90% of the occurrence of biofilm compared to the original membrane, including any values ​​and ranges in between.

[0163] Alternatively, prevention means that the presence of biofilm is reduced to at least 99.9%, 95%, 93%, 90%, 80%, 70%, 60%, 30%, 15%, 10%, or 5% compared to the original membrane. Methods for determining the level of biofilm presence are known in the art.

[0164] In some embodiments, when a growth medium is present for 24 hours, the amount of biofilm formed on the disclosed article (e.g., a filter membrane) or a filtration system containing articles with bacterial cells is less than 10. 5 CFU. In some implementations, it is below 10. 4 CFU, below 10 3 CFU, below 102 CFU or even lower. In some embodiments, the membranes of the present invention exposed to continuous filtration cycles are characterized by a microbial load of up to 10 CFU per square centimeter of membrane surface. 5 CFU, maximum 10 4 CFU, maximum 10 3 CFU, maximum 10 2 CFU, up to 10 CFU or even lower.

[0165] As described herein, such manufactured articles include, but are not limited to, processing equipment, medical devices, packaging and containers, agricultural equipment, building components, water treatment systems and components thereof, and organic waste treatment systems and components thereof.

[0166] According to some embodiments of the present invention, the compositions provided herein are packaged in packaging material and are printed on or in the packaging material to reduce or prevent the formation of biofilms and / or destroy biofilms in or on a substrate.

[0167] In some embodiments, the disclosed membrane is sterilized and used for aseptic applications.

[0168] Alternatively, the disclosed membrane may be incorporated into any article described herein during the manufacture of the article.

[0169] In one embodiment of the invention, a method for reducing the concentration of contaminants in a fluid (e.g., polluted water, PW, wastewater, etc.) is provided, comprising the step of contacting the fluid with a disclosed article (e.g., a filter membrane). In some embodiments, the contact includes filtration (e.g., by circulating polluted water through the article in a continuous mode; or in a batch mode). In some embodiments, the contact step is further repeated one or more times.

[0170] According to another aspect of the invention, a method for treating contaminated water is provided, comprising contacting the contaminated water with a membrane of the invention under suitable conditions, thereby reducing the concentration of one or more contaminants in the contaminated water. In some embodiments, the method is used to treat contaminated water to obtain treated water. In some embodiments, the terms "treated water" and "reclaimed water" are used interchangeably herein.

[0171] In some implementations, recycled water refers to water suitable for recycling. Obviously, the term "recycled water" includes water that at least meets the regulatory standards of any particular jurisdiction, allowing it to be recycled or treated into reservoirs or natural water sources such as lakes, ponds, seas, and oceans. Specifically, regulatory standards specify maximum amounts of common contaminants such as metals, heavy metals, nitrogenous species, and phosphorus species. More specifically, the term "recycled water" can include water with different thresholds for contaminants such as phosphorus species.

[0172] In some embodiments, the contaminated water used herein includes wastewater from the dairy industry, olive oil mills, wineries, pig farms, cattle sheds, slaughterhouses, fruit and vegetable processing industries, or soybean or coffee bean industries, or combinations thereof. In some embodiments, the wastewater is recreational water from coastal beaches, lakes, rivers, or ponds. In some embodiments, the wastewater includes dairy wastewater.

[0173] In some embodiments, contaminated water includes drinking water or its source, wherein the drinking water or its source is derived from rivers, lakes, reservoirs, ponds, streams, groundwater, springs, surface water and / or seawater or combinations thereof.

[0174] In some embodiments, the method is used to reduce the concentration of contaminants in contaminated water. In some embodiments, reduction includes eliminating at least 50%, at least 60%, at least 70%, at least 75%, at least 80%, at least 90%, at least 93%, at least 95%, at least 96%, at least 97%, at least 99%, at least 98%, at least 99.5%, at least 99.7%, at least 99.9%, at least 99.99%, or any range thereof, of the initial contaminant concentration in the contaminated water. In some embodiments, reduction includes eliminating 70% to 99.7%, 80% to 99.7%, 90% to 99.7%, 95% to 99.7%, or 70% to 99.99%, of the initial contaminant concentration in the contaminated water, or any range thereof. In some embodiments, reduction includes completely eliminating the contaminant in the contaminated water (e.g., to obtain treated water with a contaminant concentration below its detection limit).

[0175] The disclosed method is effective for treating one or more contaminant components, such as inorganic water contaminants (e.g., phosphorus species, such as phosphates, diphosphates, polyphosphates, etc.; nitrogen species, such as nitrates, nitrogen oxides, nitrites), organic components, such as hydrocarbons, and / or organic compounds. Examples of organic and hydrocarbon contaminant components that can be treated according to the invention include, but are not limited to, petroleum (crude oil, including top-coated crude oil), organic acids—such as benzoic acid, ketones, aldehydes, aromatic components—including phenols, etc., organic materials containing heteroatoms such as nitrogen, sulfur, and halogens, such as chlorides, dyes, polymeric materials—including, but not limited to, carbohydrates (e.g., polysaccharides), proteins, fatty acids, and mixtures thereof. Other contaminants that can be treated in this method include, for example, but not limited to, materials that are active ingredients or products in manufacturing processes, such as cyanide or hydrazine, or process byproducts, organic pesticides, herbicides, wastewater pollution, and pesticides generated from soil leaching due to continuous water use in agriculture (e.g., fruit and vegetable production, especially under arid to semi-arid climatic conditions).

[0176] definition

[0177] As used herein, the term "alkyl" describes an aliphatic hydrocarbon that includes both straight-chain and branched groups. In some embodiments, the alkyl group has 1 to 20 carbon atoms, between 1 and 10, between 1 and 5, between 5 and 10, between 10 and 15, between 15 and 20, or any range therein.

[0178] In some embodiments, the alkyl group has 21 to 100 carbon atoms, and more preferably 21 to 50 carbon atoms. Whenever a numerical range is stated herein, such as “21-100,” it means that the group—in this case, an alkyl group—can contain 21, 22, 23, etc., and up to 100 carbon atoms. In the context of this invention, a “long alkyl group” is an alkyl group having at least 20 carbon atoms in its main chain (the longest path of continuously covalently linked atoms). Thus, a short alkyl group has 20 or fewer main chain carbons. Alkyl groups can be substituted or unsubstituted, as defined herein.

[0179] As used herein, the term "alkyl" also includes saturated or unsaturated hydrocarbons, and therefore the term further includes alkenyl and ynyl groups.

[0180] The term "alkenyl" describes an unsaturated alkyl group as defined herein, having at least two carbon atoms and at least one carbon-carbon double bond. Alkenyl groups may be substituted with one or more substituents or remain unsubstituted, as described above.

[0181] As defined herein, the term "alkynyl" is an unsaturated alkyl group having at least two carbon atoms and at least one carbon-carbon triple bond. The alkynyl group may be substituted with one or more substituents or may remain unsubstituted, as described above.

[0182] The term "cycloalkyl" describes an all-carbon monocyclic or fused-ring (i.e., a ring sharing a pair of adjacent carbon atoms) group in which one or more rings do not have a fully conjugated π-electron system. Cycloalkyl groups can be substituted or unsubstituted, as described herein. Furthermore, the term "cycloalkyl" further includes heterocyclic rings, as described herein.

[0183] The term "aryl" describes an all-carbon monocyclic or fused polycyclic (i.e., a ring sharing adjacent carbon atom pairs) group having a fully conjugated π-electron system. Aryl groups can be substituted or unsubstituted, as described herein.

[0184] The term "alkoxy" describes both O-alkyl and -O-cycloalkyl, as defined herein.

[0185] The term “aryloxy group” describes -O-aryl groups, as defined herein.

[0186] Each of the alkyl, cycloalkyl, and aryl groups in the general formula herein may be substituted with one or more substituents, wherein each substituent may be independently, for example, halogen, alkyl, alkoxy, cycloalkyl, nitro, amino, hydroxyl, thiol, thioalkoxy, carboxyl, amide, aryl, and aryloxy, depending on the substituted group and its position in the molecule. Other substituents are also considered.

[0187] The terms “halogen ion,” “halogen,” or “halogen group” describe fluorine, chlorine, bromine, or iodine.

[0188] The term “haloalkyl” describes an alkyl group as defined herein, which is further substituted with one or more halogen groups.

[0189] The term “haloalkoxy” describes an alkoxy group as defined herein, which is further substituted with one or more halogen groups.

[0190] The term "hydroxyl (hydroxyl or hydroxy)" describes the -OH group.

[0191] The terms “thiol” or “mercapto-thiol” describe the -SH group.

[0192] The term “thioalkoxy” describes -S-alkyl and -S-cycloalkyl as defined herein.

[0193] The term “thioaryloxy” describes -S-aryl and -S-heteroaryl as defined herein.

[0194] The term "amino" describes the -NR'R" group, where R' and R" are as described herein.

[0195] The term "heterocyclic group" describes a monocyclic or fused-ring group having one or more atoms such as nitrogen, oxygen, and sulfur in one or more rings. The ring may also have one or more double bonds. However, rings do not have a fully conjugated π-electron system. Representative examples are piperidine, piperazine, tetrahydrofuran, tetrahydropyran, morpholine, etc.

[0196] The term “carboxyl” or “carboxylic acid ester” describes a -C(O)OR’ group, where R’ is hydrogen, alkyl, cycloalkyl, alkenyl, aryl, heteroaryl (by cyclic carbon bonding) or heterocyclic (by cyclic carbon bonding), as defined herein.

[0197] The term "carbonyl" describes the -C(O)R' group, where R' is as defined above.

[0198] The above terms also include their thio derivatives (thiocarboxyl and thiocarbonyl).

[0199] The term “thiocarbonyl” describes the -C(S)R' group, where R' is as defined above.

[0200] The “thiocarboxyl” group describes the -C(S)OR’ group, where R’ is as defined herein.

[0201] The “sulfinyl” group describes the -S(O)R' group, where R' is as defined herein.

[0202] The “sulfonyl” or “sulfonate” group describes the -S(O)2R’ group, where R’ is as defined herein.

[0203] The “carbamoyl” or “carbamate” group describes the -OC(O)NR'R” group, where R' is as defined herein and R” is as defined by R'.

[0204] The "nitro" group refers to the -NO2 group.

[0205] The term "amide" as used in this article includes both C-amides and N-amides.

[0206] As defined above for these phrases, the term “C-amide” describes the -C(O)NR'R" terminal group or the -C(O)NR'- linking group, where R' and R" are as defined herein.

[0207] As defined above for these phrases, the term “N-amide” describes the -NR”C(O)R’ terminal group or the -NR’C(O)- linking group, where R’ and R” are as defined herein.

[0208] As used herein, the term "carboxylic acid derivatives" includes carboxyl, amide, carbonyl, acid anhydride, carbonate, and carbamate groups.

[0209] "Cyano" or "nitrile" refers to the -CN group.

[0210] As defined above for these phrases, the terms “azo” or “diazo” describe the -N=NR’ terminal group or the -N=N- linking group, where R’ is as defined above.

[0211] As defined above for these phrases, the term “guanidine” describes the -R'NC(N)NR"R"' terminal group or the -R'NC(N)NR"- linking group, where R', R" and R'" are as defined herein.

[0212] As used in this article, the term "azide" refers to the -N3 group.

[0213] The term “sulfonamide” refers to the -S(O)2NR'R” group, where R' and R” are as defined herein.

[0214] The terms “phosphonoyl” or “phosphonate” describe the -OP(O)-(OR')2 group, where R' is as defined above.

[0215] The term "phosphine" describes the -PR'R" group, where R' and R" are as defined above.

[0216] The term "alkylaryl" describes an alkyl group as defined herein, which is substituted with an aryl group as described herein. An exemplary alkylaryl group is a benzyl group.

[0217] The term "heteroaryl" describes a monocyclic (e.g., C5-C6 heteroaryl ring) or fused-ring (i.e., a ring sharing adjacent atomic pairs) group having one or more atoms such as, for example, nitrogen, oxygen, and sulfur in the ring (one or more), and further having a fully conjugated π-electron system. In some embodiments, the terms "heteroaryl" and "C5-C6 heteroaryl" are used interchangeably herein. Examples of heteroaryl groups include, but are not limited to, pyrrole, furan, thiophene, imidazole, oxazole, thiazole, pyrazole, pyridine, pyrimidine, quinoline, isoquinoline, and purine. Heteroaryl groups may be substituted or unsubstituted by one or more substituents as described above. Representative examples are thiadiazole, pyridine, pyrrole, oxazole, indole, purine, etc.

[0218] As used herein, the terms “halogen group” and “halogen ion”, which are referred to interchangeably herein, describe a halogen atom that is fluorine, chlorine, bromine, or iodine, and are also referred to herein as fluorine group, chlorine group, bromine group, and iodine group.

[0219] The term "haloalkyl" describes an alkyl group as described above that is further substituted with one or more halogen groups.

[0220] As used herein, the term "substituted" or the term "substituent" refers to one or more (e.g., 2, 3, 4, 5, or 6) substituents, wherein the substituent(s) are as described herein. In some embodiments, the term "substituted" or the term "substituent" includes one or more substituents selected from: (C0-C6)alkyl-aryl, (C0-C6)alkyl-heteroaryl, (C0-C6)alkyl-(C3-C8)cycloalkyl, optionally substituted C3-C8 heterocyclic, halogen, NO2, CN, OH, CONH2, CONR2, CNNR2, CSNR2, CONH-OH, CONH-NH2, NHCOR, NHCSR, NHCNR, -NC(=O)OR, -NC(=O)NR, -NC(=S)OR, -NC(=S)NR, SO2R, SOR, -SR, SO2OR, SO2N(R)2, -NHN R2, -NNR, C1-C6 haloalkyl, optionally substituted C1-C6 alkyl, NH2, NH(C1-C6 alkyl), N(C1-C6 alkyl)2, C1-C6 alkoxy, C1-C6 haloalkoxy, hydroxy(C1-C6 alkyl), hydroxy(C1-C6 alkoxy), alkoxy(C1-C6 alkyl), alkoxy(C1-C6 alkoxy), C1-C6 alkylNR2, C1-C6 alkylSR, CONH(C1-C6 alkyl), CON(C1-C6 alkyl)2, CO2H, CO2R, -OCOR, -OCOR, -OC(=O)OR, -OC(=O)NR, -OC(=S)OR, -OC(=S)NR or combinations thereof.

[0221] As used herein, the term "C1-C6 alkyl" includes any C1-C6 alkyl-related compound, referring to any straight-chain or branched alkyl chain containing 1 to 6, 1 to 2, 2 to 3, 3 to 4, 4 to 5, or 5 to 6 carbon atoms (inclusive). In some embodiments, the C1-C6 alkyl includes any one or any combination of methyl, ethyl, propyl, butyl, pentyl, isopentyl, hexyl, and tert-butyl. In some embodiments, the C1-C6 alkyl described herein further includes an unsaturated bond located at the 1st, 2nd, 3rd, 4th, 5th, or 6th position of the C1-C6 alkyl group.

[0222] The term "(C1-C6) haloalkyl" describes a C1-C6 alkyl group as defined herein that is further substituted with one or more halogen groups such as chlorine, bromine, and / or fluorine. In some embodiments, the C1-C6 haloalkyl group is selected from: -CX3, -CHX2, -CH2X, -CH2-CX3, -CH2-CHX2, -CH2-CH2X, where X represents a halogen group. In some embodiments, the C1-C6 haloalkyl group is selected from: -CF3, -CHF2, -CH2F, -CH2-CF3, -CH2-CHF2, -CH2-CH2F.

[0223] Each R' and R independently represents hydrogen, or is selected from optionally substituted C1-C. 10 Alkyl, optionally substituted C3-C 10 cycloalkyl, optionally substituted C3-C 10 Heterocyclic groups, optionally substituted heteroaryl groups, optionally substituted aryl groups, or combinations thereof.

[0224] General Concepts

[0225] As used herein, the terms “about” or “approximately” refer to ±10%.

[0226] The terms “comprise,” “comprising,” “include,” “including,” “having,” and their synonyms mean “including but not limited to.”

[0227] The term "composed of" means "including and limited to".

[0228] The term "consistent primarily of" means that the composition, method, or structure may include additional ingredients, steps, and / or portions, provided that the additional ingredients, steps, and / or portions do not materially alter the fundamental and novel characteristics of the claimed composition, method, or structure.

[0229] The term “exemplary” is used herein to mean “used as an example, illustration, or description.” Any implementation described as “exemplary” is not necessarily to be construed as being more preferred or advantageous than other implementations and / or excluding features incorporated into other implementations.

[0230] The term "optional" is used herein to mean "provided in some embodiments but not in others." Any particular embodiment of the invention may include a number of "optional" features unless these features conflict with each other.

[0231] Unless the context clearly specifies otherwise, the singular forms “a,” “an,” and “the” as used herein include plural referents. For example, the terms “a compound” or “at least one compound” can include multiple compounds, including mixtures thereof.

[0232] Throughout this application, various embodiments of the invention may be presented in a range format. It should be understood that the range format description is for convenience and brevity only and should not be construed as a strict limitation of the scope of the invention. Therefore, the range description should be considered to have specifically disclosed all possible subranges and individual numerical values ​​within that range. For example, a description of a range such as 1 to 6 should be considered to have 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 numbers within that range, such as 1, 2, 3, 4, 5, and 6. This applies regardless of the range width.

[0233] Wherever a range of numbers is referred to herein, it means that any referenced number (fraction or integer) within the range is included. The phrases “range between the first and second indicator numbers” and “range from the first to the second indicator number” are used interchangeably herein and mean that the first and second indicator numbers, as well as all fractions and integers in between, are included.

[0234] As used herein, the term “method” means, means, techniques and procedures for accomplishing a given task, including but not limited to methods, means, techniques and procedures known to practitioners in the fields of chemistry, pharmacology, biology, biochemistry and medicine, or methods, means, techniques and procedures that can be readily developed based on methods, means, techniques and procedures of inhibition.

[0235] As used in this article, the term “treatment” includes abolishing, substantially suppressing, slowing or reversing disease progression, substantially improving the clinical or aesthetic symptoms of the disease, or substantially preventing the occurrence of the clinical or aesthetic symptoms of the disease.

[0236] It should be understood that certain features of the invention described in the context of separate embodiments for clarity may also be provided in combination in a single embodiment. Conversely, various features of the invention described in the context of a single embodiment for brevity may also be provided individually or in any suitable sub-combination, or suitably provided as in any other described embodiment of the invention. Certain features described in the context of various embodiments should not be considered essential features of those embodiments unless the embodiment would not function without these elements.

[0237] The various embodiments and aspects of the invention as described above and claimed in the appended claims are experimentally supported in the following examples.

[0238] Example

[0239] The invention is now illustrated in a non-limiting manner with reference to the following embodiments, which, together with the foregoing description, illustrate the invention.

[0240] Materials and methods

[0241] The PAN ultrafiltration flat sheet membrane (model UN050) was obtained from Zhongke Ruiyang Membrane Technology Co., Ltd. (Beijing, China). [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl)ammonium hydroxide (SBMA; determined to be approximately 95%), N,N'-methylenebisacrylamide (MBA; approximately 99%), zinc nitrate hexahydrate (Zn(NO3)2·6H2O, approximately 99%), sodium dodecyl sulfate (SDS, approximately 98.5%), and calcium chloride (approximately 98%) were all obtained from Sigma Aldrich (Saint Louis, MO, USA); 2-methylimidazole (2-MIM, approximately 98%) and dodecane (approximately 99+%) were from Tokyo Chemical Industry (Tokyo, Japan); potassium metabisulfite (K2S2O5, approximately 97%) and potassium persulfate (K2S2O8, approximately 99+%) were from Acros. Organics (USA); ethanol (EtOH), methanol (MeOH), sodium chloride (approx. 99.5+%), sodium hydroxide (approx. 99%), and sodium bicarbonate (approx. 99.7+%) were from Bio-Lab Ltd. (Israel); and anhydrous sodium sulfate (approx. 99%) and magnesium chloride hexahydrate (approx. 99%) were from CARLO ERBAReagents (France). Unless otherwise stated, all solutions were prepared in distilled water.

[0242] Membrane modification

[0243] Before membrane modification, the original PAN membrane was washed with distilled water, and then modified according to the following description. The original PAN membrane (active surface area: 0.0095 m²) was... 2 Hydrolysis was performed by treating the membrane with 500 mL of 2M NaOH aqueous solution at 65°C for 1 h, followed by thorough washing with distilled water until the pH was neutral. The hydrolyzed membrane is referred to here as the Hy membrane.

[0244] As follows, ZIF-8 nanoparticles were grown in situ on the active side of a Hy membrane at ambient temperature. The Hy membrane was cultured with shaking in a Zn(NO3)2·6H2O aqueous solution (1.25 g in 50 mL) for 12 hours. The Zn(NO3)2·6H2O aqueous solution was discarded, the membrane was washed with distilled water for 15 seconds, treated with a 2-MIM aqueous solution (2.75 g in 50 mL) with shaking for 1 hour, and then gently washed three times with a 50% MeOH aqueous solution. The Hy membrane with in-situ grown ZIF-8 nanoparticles is called a HyZif membrane.

[0245] Redox-initiated graft polymerization was carried out on the active side of Hy and HyZif membranes at ambient temperature. The membranes (active surface area: 0.00785 m²) were first treated with a 1.0 M SBMA (40 mL) aqueous solution containing 5 wt.% MBA (as a crosslinking agent) under shaking. 2 Incubate for 7.5 min; then add 5 mL each of 0.1 M K₂S₂O₅ and 0.1 M K₂S₂O₈ aqueous solutions sequentially, and continue shaking for 30 min. Terminate the reaction by discarding the reaction mixture and thoroughly washing the membrane with distilled water. The Hy-grafted membrane and HyZif-grafted membrane are referred to as the HyG membrane and HyZifG membrane, respectively.

[0246] FTIR spectra of the film surface were captured using an ATR-FTIR spectrometer (VERTEX 70, Bruker Optiks GmbH, Ettlingen, Germany). XPS analysis was performed under ultra-high vacuum conditions using an X-ray photoelectron spectrometer (ESCALAB 250, Thermo Fisher Scientific, USA) equipped with an Al Kα X-ray source and monochromator to determine the surface chemical composition of the film. XRD analysis involved measurements at 3°min in the 2θ range of 10°–38°. –1 Cu Kα radiation was performed at a scanning rate of k = (D / Max Ultima II, Rigaku Corporation, Japan). The membrane surface was observed by SEM using a JSM-IT200 instrument (JEOL, Japan). EDX element plots of the surface and cross-sectional views of the HyZifG membrane were also performed. The hydrophilicity of the membrane was investigated by measuring the contact angle of a 2 μL droplet using an OCA-20 contact angle system (DataPhysics Instruments, Filderstadt, Germany). The zeta potential of the membrane was measured at different pH values ​​in an asymmetric clamping cell using a SurPASS electric analyzer (Anton Paar, Graz, Austria). The membrane surface was observed by SEM using a NanoWizard 4 microscope (JPK Instruments, Bruker Nano GmbH, Berlin, Germany). TM The surface roughness of the membrane was examined by AFM by scanning a 5×5 μm membrane region in the mode. At least three regions of each membrane were scanned to obtain the root mean square roughness (Rm). RMS The value is taken as the average ± SD.

[0247] Pure water permeability

[0248] The pure water permeability of the membrane was measured at 1 bar using a dead-end filtration device. Figure 1 Measurements were performed after filtration for at least 30 minutes until a constant flux was reached, and the pure water permeability of each membrane was calculated using equation (1):

[0249] Pure water permeability = V / (A×Δt) (1)

[0250] Where V is the volume of permeate water (L), and A is the effective membrane area (0.00134m²). 2 ), and Δt is the duration (h). At least three readings are taken for each membrane, and the respective pure water permeability values ​​are reported as average ± SD.

[0251] Antifouling performance and oil retention efficiency of membranes used in oilfield PW treatment

[0252] The antifouling performance and oil retention efficiency of the membrane were evaluated using a simulated oilfield PW solution based on the composition of real oilfield PW. The solution had a pH of 6.5 and contained dodecane as the oil component, with the major ion concentrations typical of oilfield PW, and SDS as the surfactant (detailed composition is given in Table 1). The solution was prepared by vigorous stirring for 12 h. The oil droplet size distribution in the prepared simulated oilfield PW was measured by dynamic light scattering (DLS; ALV / CGS-8F Goniometer System, ALV-GmbH, Germany). Based on measurements conducted by the inventors, the oil droplet size distribution of the simulated oilfield PW ranged from 42 nm to 226 nm (data not shown). It was noted that the simulated oilfield PW still exhibited an oil droplet size distribution between 42.5 nm and 220 nm after two days of stirring, similar to the droplet size distribution at the start of the filtration experiment. Therefore, it can be inferred that the feed solution remained stable during the filtration experiment.

[0253] Table 1. Composition of PW in simulated oilfield

[0254] dodecane <![CDATA[g·L –1 ]]> 1.0 chloride <![CDATA[g·L –1 ]]> 5.2 bicarbonate <![CDATA[g·L –1 ]]> 0.2 sulfates <![CDATA[g·L –1 ]]> 1.0 sodium <![CDATA[g·L –1 ]]> 2.0 calcium <![CDATA[g·L –1 ]]> 1.0 magnesium <![CDATA[g·L –1 ]]> 0.4 SDS <![CDATA[g·L –1 ]]> 0.1 pH - 6.5

[0255] Using simulated oilfield PW, the antifouling performance of PAN, Hy, HyG, and HyZifG membranes was evaluated through dead-end mode filtration experiments (see [link]). Figure 1 First, distilled water was filtered through each membrane for 1 hour to obtain a stable initial water flux (approximately 100 L·m). -2 ·h -1 ), represented as J W0 Next, three filtration cycles (fouling, membrane cleaning, and water flux measurement) are performed. Each cycle includes the following steps: Step 1 – Filter the simulated oilfield PW for 3 hours, recording the flow rate every minute. At regular time intervals, the collected permeate is added back to the stirred filter tank to maintain a constant feed solution concentration throughout the process; Step 2 – Discard the oilfield PW and filter with 80 L distilled water / m³. 2 Membrane agitation for 15 minutes to clean the membrane (note that the distilled water washing step is not included in the filtration cycle time); Step 3 – Measure the water flux of the clean membrane for 1 hour, with cycles 1, 2, and 3 expressed in J. W1 J W2 and J W3 (L·m -2 ·h -1 Equation (1) is used to calculate the water flux. To clarify the membrane's antifouling performance, Equation (2) is used to calculate the FRR of the i-th (i = 1, 2, 3) filtration cycle:

[0256]

[0257] The oil retention efficiency (R) of these films was calculated using equation (3). exp ),

[0258]

[0259] Where C p and C f The values ​​represent the permeate and feed oil concentrations, respectively, measured using a total organic carbon (TOC) analyzer (Multi N / C 2100S, AnakitikJena GmbH, Germany).

[0260] The stability of the methacrylate hydrogel-grafted ZIF-8 layer on the HyZifG membrane was examined by comparing FTIR spectra and DXE elemental analysis before and after the contamination experiment. Furthermore, ZIF-8 nanoparticles leached from the HyZifG membrane were detected by collecting retained samples (15 minutes after the start of the contamination filtration experiment) and permeate samples (at regular time intervals) and analyzing them using inductively coupled plasma optical emission spectrometry (ICP-OES, SPECTROARCOS, AMETEK, Inc., USA). The limits of detection and quantitation for zinc by ICP-OES were 1 ppb and 10 ppb, respectively.

[0261] A HyZifG membrane was selected for long-term antifouling experiments. Simulated oilfield produced water was used as the contaminant solution for 10 filtration cycles. The filtration scheme was the same as described above.

[0262] Example 1

[0263] Preparation of ZIF-8 modified film and stabilization of ZIF-8 layer

[0264] Hydrophilic carrier membranes should provide higher flux, better oil rejection and lower fouling than hydrophobic membranes. Therefore, PAN membranes were chosen as porous carriers because of their higher hydrophilicity than PVDF carriers. In addition, the continuous ZIF-8 nanoparticle layer formed by in-situ growth on the membrane surface requires the presence of surface ligand groups, such as carboxyl groups. Therefore, the original PAN membrane was partially hydrolyzed (Scheme 1, Step 1) to introduce surface carboxyl groups to provide sufficient anchoring sites, thereby forming a continuous ZIF-8 nanoparticle layer on the membrane surface (Scheme 1, Step 2)

[34] . SEM analysis showed that the ZIF-8 nanoparticle layer covered the surface of the Hy membrane ( Figure 14A -C). It is worth noting that the in-situ growth of ZIF-8 nanoparticles was carried out on the membrane surface under conditions compatible with the porous UF membrane (in water at room temperature).

[0265] Finally, to chemically stabilize the ZIF-8 layer, a cross-linked zwitterionic hydrogel containing sulfonic acid groups was introduced. Redox-initiated graft polymerization introduced a methacrylate zwitterionic hydrogel onto the ZIF-8 layer to maintain its integrity and stability. Figure 2 (Step 3). The coating of the ZIF-8 nanoparticle layer with the redox-grafted methacrylate hydrogel can be seen in SEM images (Figs. S4-E). The membrane was characterized using various techniques to elucidate its physicochemical properties and its performance in oilfield PW processing was investigated.

[0266] Figure 3 shows the FTIR spectrum of the modified membrane compared to the original PAN membrane. The FTIR spectrum of the original PAN membrane is at 1451 cm⁻¹. –1 and 2245cm –1 A peak is observed at this location, corresponding to the C–N stretching of the -C≡N group. Further, at 2939 cm⁻¹... –1 The peak at 1737 cm⁻¹ corresponds to C–H stretching. –1 The additional peak at 1565 cm⁻¹ corresponds to carbonyl-C=O stretching (in carboxylic acids or esters) and is likely due to additives present in commercial PAN films. Hydrolysis of the PAN film (Hy film) results in a peak at 1565 cm⁻¹. –1 and 1668cm –1 The prominent peak at 1405 cm⁻¹ corresponds to the NH group in carboxamide and carbonyl (C=O) [39,40], and the peak at 1405 cm⁻¹. –1 The new peak at 3200-3500 cm⁻¹ indicates the presence of carboxyl groups on the surface of the Hy membrane

[40] . Furthermore, the peak at 3200-3500 cm⁻¹... –1 The peaks appearing between these peaks correspond to the O–H moieties of the carboxyl groups on the membrane surface. The appearance of these peaks confirms the partial hydrolysis of the PAN membrane. In-situ growth of ZIF-8 nanoparticles on the Hy membrane provides the HyZif membrane (Figure 3), at 683 cm⁻¹ –1 758cm –1 1378cm –1 and 2870cm –1 Characteristic peaks of ZIF-8 nanoparticles were observed at 1043 cm⁻¹, corresponding to the stretching vibrations of ZnO bonds in octahedral coordination, the bending vibrations of the imidazole ring, the bending vibrations of the -CH₃ group in 2-methylimidazolium, and the aliphatic C–H stretching of the imidazole ring, respectively. The presence of these peaks confirms the presence of ZIF-8 nanoparticles on the membrane surface. Grafting poly(methacrylate) hydrogel onto the Hy membrane provides the HyG membrane with characteristic peaks at 1043 cm⁻¹. –1 (Sulfonate S=O stretching), 1229cm –1 (CO–NH stretching vibration of the amide group), 1672 cm⁻¹ –1 (amide C=O), 1729cm –1The peak at (ester C=O stretching) and the peak corresponding to the stretching vibration of NH in the amide group of poly(MBA-co-SBMA) at 3250–3450 cm⁻¹ –1 The presence of broad peaks between these peaks confirms the presence of grafted methacrylate hydrogel on the membrane surface. The FITR spectrum of the HyZifG membrane exhibits characteristic peaks from ZIF-8 nanoparticles (observed in the FTIR spectrum of the HyZif membrane) and characteristic peaks from the grafted methacrylate hydrogel (observed in the FTIR spectrum of the HyG membrane), confirming the modification of the membrane by both ZIF-8 nanoparticles and the grafted hydrogel. These different groups on the membrane surface affect the membrane's surface properties, thereby influencing its separation performance, as described later.

[0267] The surface elemental composition of the prepared membrane was quantified using XPS analysis (Table S1).

[0268] Table S1. Surface elemental composition (atomic %) of different films obtained by XPS analysis a

[0269] PAN 75.73 4.89 19.38 Nd Nd Hy 71.91 12.57 15.52 Nd Nd HyG 67.03 19.31 10.75 2.92 Nd HyZif 66.71 5.28 19.06 Nd 8.95 HyZifG 76.91 13.27 6.63 1.41 1.78

[0270] a Nd, not detected.

[0271] The broad XPS spectrum of these films also shows Figure 3B The results indicate that the O content increases with the hydrolysis of the original PAN membrane, suggesting a higher prevalence of oxygen-rich surface groups on the Hy membrane compared to the original PAN membrane. By grafting polymethacrylate hydrogel, the HyG membrane exhibits increased S content due to the sulfonic acid groups in the SBMA polymer, confirming the membrane modification by the grafted methacrylate hydrogel. Zinc appears in the HyZif membrane, accompanied by low oxygen and high nitrogen content, confirming the in-situ growth of ZIF-8 nanoparticles on the membrane surface. Grafting the ZIF-8 layer onto the HyZif membrane with methacrylate hydrogel (HyZifG membrane) resulted in a decrease in zinc content, the reappearance of sulfur, and an increase in oxygen content in the HyZifG membrane. Therefore, XPS surface analysis confirmed the successful membrane modification.

[0272] Figure 4 shows the XRD spectra of the prepared films. The PAN film spectrum has three peaks, with the peak at 2θ = 18° characteristic of the hexagonal crystals of PAN, and the other two peaks at 2θ = 22.8° and 26.1° likely attributable to the crystalline phase of the PAN film. These peaks were also observed in the Hy and HyG films, with slightly different intensities. Compared to the original film, the peak intensity at 2θ = 22.8° in the HyZif and HyZifG films was significantly reduced, due to the presence of the ZIF-8 nanoparticle coating, which masked the underlying PAN support. The HyZif film provided several diffraction peaks at 2θ = 7.5°, 10.5°, and 12.8° attributable to the ZIF-8 nanoparticles, corresponding to (011), (002), and (112) reflections, respectively (the XRD spectrum of the original ZIF-8 nanoparticles is shown in Figure 4). Figure 4B (As shown). In addition, two diffraction peaks appeared at 2θ = 17.8° and 26.1°, corresponding to (222) and (134) reflections, respectively, which are consistent with the peaks recorded in the original PAN spectrum. These peaks were also recorded on the HyZifG film, confirming that the PAN film was integrally modified by the ZIF-8 layer grafted with methacrylate hydrogel.

[0273] EDX elemental mapping was performed on the cross-section and surface of the HyZifG membrane to explore the distribution of ZIF-8 nanoparticles on the membrane. Figure 5A -B shows the microstructure of C, N, O, and Zn on the HyZifG membrane. Elemental zinc is a characteristic component of ZIF-8 nanoparticles, and the presence of a ZIF-8 layer stabilized by a methacrylate hydrogel layer on the membrane surface is confirmed.

[0274] The surface charge of the membrane is crucial for separation applications, and the zeta potential of PAN, Hy, and HyG membranes was measured using the flow potential method. Figure 13 At pH values ​​above 4.0, all membranes exhibited a net negative surface charge, with the pristine PAN and Hy membranes showing the largest negative values. However, the Hy membrane exhibited a steep titration slope in the pH range of 3.0–5.5 (isoelectric point of pH 4.0), typical of carboxyl titration, clearly indicating a high concentration of carboxyl groups on the Hy membrane surface. Redox-initiated graft polymerization on the Hy membranes yielded the HyG membrane, which exhibited a generally reduced negative surface charge (lower negative zeta potential) compared to the pristine membrane. This is likely due to the zwitterionic-neutral nature of the SBMA monomer used in the polymerization reaction and partial masking of the membrane surface. Zeta potential measurements confirmed the successful hydrolysis of the pristine PAN membrane and subsequent modification with a methacrylate hydrogel. Furthermore, at pH 6.5 (the working pH for the antifouling experiment), the HyZifG membrane had a zeta potential of -14.5 ± 0.6 mV, indicating that all studied membranes possessed negative zeta potential values ​​at the working pH.

[0275] Surface roughness is an important property of membranes used in separation applications and can influence the tendency of membrane fouling. Membrane surface roughness is measured using AFM, expressed as R0. RMS (Figure 7). R of the original PAN film. RMS The value is 26.2±1.8 nm, and the R of the Hy film is... RMS The roughness of the HyG membrane decreased to 21.3 ± 1.4 nm, indicating that hydrolysis smoothed the membrane surface. The roughness was further reduced to 16.9 ± 1.0 nm due to the coating of a methacrylate hydrogel layer via redox-initiated graft polymerization. AFM analysis was performed in water, where the hydrogel layer swelled, and thus a smooth surface was expected. The in-situ growth of ZIF-8 nanoparticles on the Hy membrane surface increased the roughness of the HyZif membrane to 30.6 ± 2.5 nm due to the heterogeneous surface formed by ZIF-8 nanoparticles. Compared to the Hy membrane, the redox grafting of the methacrylate hydrogel reduced the surface roughness of the HyZifG membrane to 24.6 ± 2.0 nm, consistent with the reduced roughness of the HyG membrane. The interaction between membrane wettability and roughness will affect its separation performance in treating oilfield PW and its antifouling behavior, which will be discussed later.

[0276] Example 2

[0277] Membrane performance

[0278] The performance of the exemplary membrane of the present invention (prepared according to the above method) in oilfield PW treatment was studied in terms of pure water permeability, antifouling properties and oil retention efficiency.

[0279] Pure water permeability

[0280] High purity water permeability is desirable for separation applications. Figure 8 The pure water permeability of the prepared membrane is shown. The pure water permeability of the PAN membrane is 396.1 ± 6.5 L·m⁻¹. -2 ·h -1 ·bar -1 The pure water permeability of the Hy and HyG membranes increased to 546.5 ± 8.3 L·m⁻¹, respectively. -2 ·h -1 ·bar -1 (Increased by 138%) and 676.2 ± 8.7 L·m -2 ·h -1 ·bar -1 (An increase of 171%). This increase in pure water permeability can be attributed to the hydrophilicity of the membrane, as can be seen from its water contact angle value. This is due to the presence of water-absorbing functional groups on the membrane surface, as discussed in the FTIR study (Figure 3). The pure water permeability of the HyZifG membrane was 447.9 ± 6.7 L·m⁻¹. -2 ·h -1 ·bar-1 The hydrophilicity is approximately 13% higher than that of the original PAN membrane, consistent with its higher hydrophilicity, which is desirable for separation applications. Due to its relatively low hydrophilicity (higher water contact angle), the pure water permeability of HyZifG is lower than that of Hy and HyG membranes.

[0281] Antifouling properties of oilfield PW filters

[0282] The composition and properties of petroleum-derived waste (PW) produced in the oil and gas industry vary depending on the geographical location and drilling technology used. The inventors compiled information from various locations and designed a test solution with a typical oilfield PW chemical composition in terms of major ions, pH, and salinity, using dodecane as the hydrocarbon component (see Table 1 for composition and properties). Antifouling experiments were conducted using PAN, Hy, HyG, and HyZifG membranes to simulate oilfield PW, elucidating the specific antifouling contributions of PAN hydrolysis, redox-induced graft polymerization, and the ZIF-8 layer to the overall membrane performance.

[0283] Figure 9 The filtration of different membranes in a simulated oilfield PW was demonstrated to determine their membrane antifouling behavior. By adjusting the pressure, all membranes achieved a stable initial permeate flux (100 L·m⁻¹). -2 ·h -1 As the fouling experiments proceeded, the flux of each membrane varied according to its antifouling properties. Figure 9 Three filtration cycles are shown. The antifouling behavior of the membranes is expressed as FRR in Table 2. It is clear from the data that the original PAN membrane is easily fouled, as the FRR decreases significantly with each fouling cycle (FRR for the first, second, and third fouling cycles are 49.9 ± 0.9%, 29.4 ± 0.6%, and 8.1 ± 0.7%, respectively). The Hy and HyG membranes (modified by hydrolysis and graft polymerization, respectively) provide FRR values ​​that gradually increase compared to the original PAN membrane, indicating that all modification steps contribute to the antifouling behavior. The FRR values ​​of the Hy membrane (69.9 ± 1.4%, 55.2 ± 1.5%, and 40.1 ± 1.7% for the first, second, and third fouling cycles, respectively) are higher than the calculated values ​​for the original PAN membrane, and the FRR values ​​of the HyG membrane are 82.5 ± 1.3%, 73.8 ± 1.6%, and 61.7 ± 1.5%, respectively. Therefore, the observed trend is FRR(HyG) > FRR(Hy) > FRR(PAN), reflecting the hydrophilicity and surface roughness of the Hy and HyG membranes. Hydrophilic membranes with smooth surfaces facilitate the formation of a hydration layer on the membrane surface, thereby resisting fouling deposition and exhibiting high antifouling performance. The inventors observed that the hydrophilicity of the membrane (as can be seen from the water contact angle value)... Figure 6 ) and surface smoothness (film surface roughness, R RMSThe values ​​(Figure 7) follow the trend HyG>Hy>PAN, consistent with their antifouling performance. Significantly, the HyZifG membrane exhibits superior antifouling performance in filtering oilfield PW (pollution), demonstrating excellent antifouling capabilities, as shown by the FRR values ​​of 99.5±0.5%, 99.1±0.7%, and 98.5±0.6% in the first, second, and third fouling cycles, respectively. The HyZifG membrane shows remarkable ability to immediately recover its original flux with only slight loss after cleaning the membrane surface by washing (stirring in distilled water for 15 min).

[0284] The excellent antifouling behavior of the HyZifG membrane can be attributed to the presence of a methacrylate hydrogel-grafted ZIF-8 layer on the membrane surface, which is hydrophilic and highly resistant to the adhesion of oily contaminants. Furthermore, the low MWCO value (Table S2) caused by the methacrylate hydrogel-grafted ZIF-8 layer on the HyZifG membrane surface prevents oily contaminants from clogging the pores and preferentially allows water to permeate through the membrane, resulting in high water flux. Figure 10 Therefore, HyZifG membranes exhibit the best antifouling performance.

[0285] Table 2. PW in each simulated oilfield a Flux recovery rate (FRR) of PAN, Hy, HyG, and HyZifG after filtration cycle. Value surface The value is shown as mean ± SD, n = 3.

[0286]

[0287] a The chemical composition of the solution is detailed in Table 1.

[0288] SEM studies of the membrane surfaces before and after filtration further support the observed trend in the antifouling performance of membrane-filtered oilfield PWs (Figure 11). SEM images show that the surface of the pristine PAN membrane exhibits the highest amount of contaminant adhesion. In contrast, the HyZifG membrane shows negligible contaminant adhesion, supporting its superior antifouling performance in oilfield PWs. As determined by comparing the FTIR spectra of the membranes before and after the fouling experiment, the HyZifG membrane remained stable even after three 4-h filtration cycles. Figure 12The FTIR spectrum of the filtered HyZifG membrane showed all the major characteristic peaks of the ZIF-8 nanoparticles observed with the fresh membrane (before the start of the fouling experiments), confirming that the ZIF-8 layer on the membrane surface remained intact even after all filtration experiments. Furthermore, the EDX elemental composition of the fresh and used HyZifG membranes remained almost identical (Table S3), indicating the stability of the ZIF-8 layer under the methacrylate hydrogel on the HyZifG membrane. Further, Zn in the retained and permeate was measured using ICP-OES. 2+ The concentration was used to examine the leaching of ZIF-8 nanoparticles from the HyZifG membrane during the contamination experiment. ICP-OES analysis did not detect Zn in the retained and permeate below the detectable limit of ICP (1 ppb). 2+ This means that the water stability of the ZIF-8 layer in the HyZifG membrane was tested during the antifouling filtration experiment and at the ICP analysis threshold.

[0289] The oil retention efficiency (R) of the prepared membrane was found to be... exp The oil rejection rates (MWCOs) of the HyZifG membrane followed the same trend as their antifouling performance. The HyZifG membrane had the highest MWCO value (99.7 ± 0.3%), followed by the HyG membrane (97.5 ± 0.6%), the Hy membrane (96.9 ± 0.7%), and the original PAN membrane (96.5 ± 0.5%). The rejection rates of the different membranes trended in line with their MWCO values ​​(Table S2). The original PAN membrane had the highest MWCO value (325.4 kDa) and showed an oil rejection rate of 96.5 ± 0.5%. On the other hand, the HyZifG membrane had the lowest MWCO value (265.2 kDa), showing the highest oil rejection rate (99.7 ± 0.3%), followed by the HyG membrane (97.5 ± 0.6%) and the Hy membrane (96.9 ± 0.7%), with MWCO values ​​of 305.6 and 310.7 kDa, respectively. Clearly, size exclusion was the dominant separation mechanism for the four tested membranes. The superior oil rejection efficiency of the HyZifG membrane can be attributed to the presence of the ZIF-8 layer, which leads to a decrease in the MWCO value, thereby hindering the passage of oil through the membrane [10,51,52]. The membrane rejection for ions in simulated PW solutions was measured using ICP analysis of the feed and permeate, and is given in Table S4. The obtained rejection values ​​ranged from 1% to 16%, with the highest rejection value measured for the HyZifG membrane. For the UF membrane, a lower rejection value for inorganic ions is expected.

[0290] The antifouling performance of the HyZifG membrane was tested for 42 hours (10 filtration cycles) and the results are presented in... Figure 13In the filtration process, the HyZifG membrane exhibited an FRR of 90.3% after 10 filtration cycles. The gradual decrease in FRR after each cycle can be attributed to fouling over time. Notably, the oil retention efficiency remained >99% throughout the filtration period. These results clearly demonstrate the excellent suitability of the HyZifG membrane for treating oilfield produced water.

[0291] The performance of the HyZifG membrane in treating oilfield PW was compared with previously reported membranes for treating oily wastewater. The performance of the exemplary membrane of the present invention is illustrated in Table 3. As shown in Table 3, the exemplary HyZifG membrane of the present invention exhibits excellent antifouling capability (FRR of approximately 90.3%) and oil retention efficiency (>99%) in oilfield PW treatment.

[0292] Table 3. Performance of HyZifG in treating PW in oil fields as described in this paper.

[0293]

[0294] In summary, the results presented and discussed here demonstrate the successful design and fabrication of the HyZifG membrane, showcasing its excellent antifouling properties, high water flux, high oil removal efficiency, and stability during filtration. Therefore, the polyacrylonitrile membrane with a methacrylate hydrogel-grafted ZIF-8 layer, prepared using the described simple method, shows promise for the separation and treatment of petroleum waste (PW) in oilfields.

[0295] Molecular weight cutoff (MWCO) analysis

[0296] Use polyethylene glycol (M) n =35 kDa; Sigma Aldrich, MO, USA) and polyethylene oxide (Mn = 100, 200, 400 and 600 kDa; Sigma Aldrich, MO, USA) were used as molecular markers to determine the MWCO of the membrane. 1 g·L⁻¹ of each molecular marker was prepared in Milli-Q water. -1 Solution, and use at 1 bar at room temperature. The agitated dead-end filter (300 rpm) was used to filter the material through a membrane. The feed concentration (C) was measured using a TOC analyzer (Multi N / C, 2100S, Anaritikjena, Germany). f ) and permeate (C p The total organic carbon (TOC) concentration of the solution was measured, along with the concentration of the molecular marker in the feed and permeate. The percentage rejection of the marker was calculated using the following equation (S1) and plotted against its molecular weight:

[0297]

[0298] The MWCO value (defined as the molecular weight at 90% rejection) for each membrane was calculated from the relationship between rejection and molecular weight. The MWCO values ​​for different membranes are given in Table S2.

[0299] Table S2. MWCO data for different membranes

[0300] PAN 325.4 Hy 310.7 HyG 305.6 HyZifG 265.2

[0301] Table S3. EDX elemental composition of fresh and used HyZifG membranes (in mass %)

[0302] C 54.89±0.36 55.02±0.55 N 18.36±0.50 18.34±0.47 O 19.28±0.29 19.22±0.37 S 2.97±0.05 2.96±0.06 Zn 4.50±0.11 4.46±0.15

[0303] Table S4. Ion rejection rates (%) of different membranes

[0304] PAN 4.6 2.7 2.6 2.2 1.4 Hy 5.3 3.6 3.0 2.5 1.9 HyG 8.3 5.4 4.1 4.0 2.9 HyZifG 15.3 8.7 8.4 7.6 6.8

[0305] Example 3

[0306] COF-300 nanoparticles stabilized on polymer membranes for efficient removal of PFAS contaminants from polluted water.

[0307] COF-300 nanoparticles were prepared as follows: 0.053 mmol of tetrakis(4-aminophenyl)methane (TAPM) was completely dissolved in 1,4-dioxane, and the mixture was heated at 50-60 °C for 5 min. After cooling the solution to room temperature, 1.7 mmol of acetic acid and water were mixed and added to the above mixture. Terephthalaldehyde (TPA; 0.089 mmol) was dissolved in dioxane and added to the TAPM solution. The mixture was kept at 120 °C for 72 h. The reaction mixture was cooled to room temperature. The resulting yellow solid was then washed according to the following procedure: (1) centrifuged 3 times with 1,4-dioxane; (2) shaken in 1,4-dioxane for 24 h; (3) centrifuged to discard the 1,4-dioxane; (4) centrifuged 3 times with isopropanol; (5) shaken in isopropanol for 24 h; (6) centrifuged to discard the isopropanol. Finally, the solid was vacuum dried at 60 °C for 24 h.

[0308] The morphology of the prepared nanoparticles was characterized by scanning electron microscopy (SEM), their chemical functionality was characterized by Fourier transform infrared spectroscopy (FTIR), and their crystallinity was characterized by X-ray diffraction (XRD). The SEM image (Figure 15(AB)) shows the elliptical shape of the COF nanoparticles. The FTIR spectra of the prepared nanoparticles are shown in... Figure 1 -C shows that COF-300 nanoparticles at 1625 cm⁻¹ -1 (attributed to imine C=N stretching) and 2926 cm -1The characteristic peaks at (attributed to the CH stretching of the olefins by imines) confirmed their structure [Uribe-Romo et al. Journal of the American Chemical Society 131 (2009) 4570-4571]. Other important peaks were also recorded at 947 cm⁻¹. –1 (Aromatic CH out-of-plane vibration of TAPM), 1007 cm⁻¹ –1 (TAPM's aromatic CH plane in-plane curvature), 1480cm –1 (Aromatic C-ring stretching of benzene ring), 1512cm –1 (Aromatic ring stretching of the benzene ring in TAPM) and 1836 cm –1 (Aromatic CH bending overtones).

[0309] Figure 15-D shows the XRD pattern of COF-300 nanoparticles. Characteristic peaks appear at 6.3° (110), 8.8° (200), 12.5° (220), 13.9° (211), 16.6° (301), 18.9° (321), 19.9° (420), 20.8° (411), 24.5° (501), 26° (521), 28.3° (422), 29.1° (611), and 30.5° (512) [Uribe-Romo et al. Journal of the American Chemical Society 131 (2009) 4570-4571], confirming the successful synthesis of COF-300 nanoparticles. The PAN UF membrane was hydrolyzed as described above (Example 1, and materials and methods).

[0310] Then, COF-300 nanoparticles were deposited on the hydrolyzed PAN membrane via vacuum filtration. The loading of COF-300 nanoparticles was 20 μg·cm³. -2 . Figure 16 SEM images of COF-300 nanoparticles deposited on the membrane surface are shown. Next, as described above, redox-initiated graft polymerization was performed on the membrane surface (Example 1, Materials and Methods). FTIR analysis revealed characteristic peaks in both the methacrylate hydrogel and the COF-300 nanoparticles, confirming the success of the membrane modification.

[0311] The separation performance of the modified membrane was measured. The pure water permeability was 68.6 L·m⁻¹. –2 ·h –1 ·bar –1Furthermore, the removal efficiency of PFOA was determined by filtering real groundwater samples contaminated with PFOA. The groundwater samples were collected from a well (Yad Mordechai-1) near Yad Mordechaikibbutz, and their composition is shown in Table 4. The groundwater was contaminated with PFOA at a concentration of 500 ppb. The modified membrane removed 67.6% of the PFOA and 74.3% of the nitrate from the contaminated real groundwater samples, with a permeate flux of 52.9 L·m⁻¹. –2 ·h –1 (Under 2 bars).

[0312] Table 4. Composition of contaminated groundwater samples collected from Yad Mordechai kibbutz

[0313] nitrates 70 <![CDATA[mg·L –1 ]]> bicarbonate 265 <![CDATA[mg·L –1 ]]> boron 0.2 <![CDATA[mg·L –1 <!-- 27 -->]]> bromide 0.6 <![CDATA[mg·L –1 ]]> calcium 78 <![CDATA[mg·L –1 ]]> chloride 150 <![CDATA[mg·L –1 ]]> Fluorides 0.7 <![CDATA[mg·L –1 ]]> Potassium 4.1 <![CDATA[mg·L –1 ]]> sodium 87 <![CDATA[mg·L –1 ]]> sulfates 43 <![CDATA[mg·L –1 ]]> DO 8.1 <![CDATA[mg·L –1 ]]> EC 1050 <![CDATA[μS·cm –1 ]]> pH 7.5 -

[0314] Crosslinking degree evaluation

[0315] In addition to using hydrophilic monomers, the inventors also used 2.5 and 5 wt.% MBA crosslinking agents during graft polymerization to manufacture the coating membrane disclosed herein as a way to stabilize the functional nanoparticles on the membrane surface without impairing its separation performance.

[0316] The antifouling performance of the modified membrane was examined by measuring the flux after filtration of PFAS-contaminated water and subsequent washing with water. A flux recovery rate of 96% indicates excellent antifouling properties. Membrane stability was also examined by recording the FTIR spectrum of the modified membrane and comparing it with the spectrum before filtration. This comparison showed that the spectra remained consistent, indicating that the modified (COF-300 / methacrylate hydrogel) layer remained intact after extensive filtration experiments. These results demonstrate that the membrane modified with a methacrylate hydrogel-stabilized COF-300 nanoparticle layer effectively removes PFOA from contaminated groundwater.

[0317] Further examples of COF-300 nanoparticles deposited on PAN films (PAN RS50 films) have been prepared. The inventors have successfully fabricated nanoparticles with different surface densities of 187, 93, and 23 μg / cm³ on the film. 2 The PAN film. The COF nanoparticles have a length of approximately 0.5 μm. Furthermore, the different surface densities result in similar top views of the nanoparticle top layer.

[0318] Results of stabilizing nanoparticles without using crosslinking agents

[0319] To further demonstrate the importance of using MBAA crosslinking agents in grafting, we conducted preliminary experiments to stabilize a layer of ZIF-8 nanoparticles on a membrane surface in redox-initiated graft polymerization without any crosslinking agent. The stability of the nanoparticle layer on the modified membrane was examined by EDS elemental analysis of fresh and used (after filtration experiments) membrane samples. The composition of zinc (a component of ZIF-8 nanoparticles) was found to decrease from 4-5 wt.% to less than 0.1 wt.%, indicating that the hydrogel (without crosslinking agent) is unsuitable for stabilizing the nanoparticle layer on the membrane surface. Notably, the zinc composition in the membrane modified with the crosslinked hydrogel remained the same (4-5 wt.%) after numerous filtration experiments. Based on the above, the criticality of using crosslinked polymers in the coatings of this invention should be recognized. It is speculated that the optimal degree of crosslinking of the polymers disclosed herein is between 1 and 20%. Alternatively, as disclosed herein, the w / w ratio and / or molar ratio between the polymer and the crosslinking agent is between 1 and 20%.

[0320] Furthermore, the inventors have successfully prepared various CFS on polymer films, which are stabilized by the graft copolymers disclosed herein.

[0321] For example, ZIF-8 nanoparticles in situ grown on a PAN film with a molecular weight cutoff of 325.4 kDa; ZIF-67 nanoparticles in situ grown on a PAN film with a molecular weight cutoff of 105 kDa; Co / Zn-based ZIF-L nanoparticles (particle size between 1 and 10 μm) in situ grown on a PAN film with a molecular weight cutoff of 105 kDa; Zn-based ZIF-L particles (particle size between 1 and 5 μm) in situ grown on a polyether sulfone (PES) film with a molecular weight cutoff of 75 kDa; and ZIF-8 nanoparticles in situ grown on a PES film with a molecular weight cutoff of 50 kDa have been successfully prepared and stabilized by graft copolymers as disclosed herein.

[0322] Example 4

[0323] Ultrafiltration water treatment membrane

[0324] Material

[0325] Nanofiltration (NF90 and NF200) and polyacrylonitrile (PAN) ultrafiltration sheet membranes were supplied by DuPont FilmTec Co. (Midland, MI, USA) and Zhongke Ruiyang Membrane Technology Co., Ltd. (Beijing, China), respectively. Tris(hydroxymethyl)aminomethane (Tris buffer, 99.8%) was purchased from Acros Organics Co. (St. Janssen-Pharmaceuticalaan 3a, B-2440 Geel, Belgium). Dopamine hydrochloride (99%) and fluorinated monomers of 2,2,3,4,4,4-hexafluorobutyl methacrylate were obtained from Thermo Fisher Scientific (St. Shore, Lancashire, UK). [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl)ammonium hydroxide (SBMA, 95%), N,N'-methylenebis(acrylamide) (MBA, 99%), and cobalt(II) nitrate hexahydrate (98%) were obtained from Sigma-Aldrich Chemical Co. (St. Louis, MO, USA). 2-Methylimidazole (2-MIM, 98%) was purchased from Tokyo Chemical Industry (Tokyo, Japan). All chemicals used in this study were not further purified.

[0326] Hexane, anhydrous ethanol, anhydrous methanol, and isopropanol (IPA) were purchased from Bio-Lab Ltd. (Jerusalem, Israel). Photoinitiator benzophenone (BP, 99%) and bovine serum albumin (98%) were obtained from Sigma-Aldrich Chemical Co. (St. Louis, MO, USA). Potassium hydroxide flakes were purchased from Bio-Lab Ltd. (Jerusalem, Israel).

[0327] Barium chloride dihydrate (99%), potassium nitrate (99%), calcium chloride dihydrate (99%), ferric(III) nitrate nonahydrate (98%), zinc sulfate heptahydrate (ZnSO4·7H2O), sodium fluoride (99%), and sodium tetraborate (99%) were purchased from Sigma-Aldrich Chemical Co. (St. Louis, MO, USA). Sodium chloride (98%) and anhydrous magnesium sulfate (99%) were purchased from Bio-Lab Ltd. (Jerusalem, Israel) and Carlo Erba Reagents Co. (Sabadell, Barcelona, ​​Spain), respectively. Deionized (DI) water was used in all experiments unless otherwise specified.

[0328] Modification of PAN-UF composite membranes by hydrogel-stabilized MOFs

[0329] Hydrolysis of PAN membrane. The original PAN membrane (surface area 0.00541 m²) was subjected to hydrolysis. 2 The membrane was washed with water overnight, and then hydrolyzed at 60°C and 300 rpm with 1M KOH aqueous solution for 1 h. The membrane was then rinsed with deionized water for up to 14 days to neutralize the pH of the solution. The resulting membrane was named the Hy membrane.

[0330] A ZIF-67 nanoparticle layer was formed in situ on a Hy membrane. An aqueous solution of Co(NO3)2·6H2O (0.44 g, 30 mL) was prepared and incubated with the Hy membrane at 25 °C with continuous shaking at 85 rpm for 12 h. The Co(NO3)2·6H2O aqueous solution was then discarded, and the membrane was washed with DI water for 1 min with shaking. Then, the membrane was incubated with an aqueous solution of 2-methylimidazolium (2-MIM) organic linker (0.974 g, 30 mL) with continuous shaking at 85 rpm for 9 h. The 2-MIM solution was discarded, and the membrane was washed three times with flowing DI water. The Hy membrane with the in-situ grown ZIF-67 nanoparticles was named HyZIF67.

[0331] Graft polymerization was performed using zwitterionic methacrylate monomers. Hy and HyZIF67 membranes were surface modified by graft polymerization under UV irradiation for 5, 7.5, and 10 min. First, the membranes were incubated with BP photoinitiator (0.05 M and 0.1 M, in 30 mL of 80% ethanol / water solution) for 10 min and 30 min, respectively. The BP solution was then discarded, and the membrane surface was washed with water for 1 min with shaking at 85 rpm to remove residual BP. Next, the membranes were incubated with a 0.8 M SBMA solution containing 0.04 M MBA as a crosslinking agent in 30 mL of water solution with shaking. The SBMA / MBA solution was incubated on the membrane surface for 30 seconds at 25 °C, followed by UV grafting. The process was kept in darkness before irradiation to avoid UV activation. The membranes were then irradiated with 50% UV light intensity for 5, 7.5, and 10 min. The grafted membranes were removed and immediately rinsed with DI water to remove any unreacted and ungrafted SBMA monomers and chains from the membrane surface. The SBMA-co-MBA-grafted Hy and HyZIF67 membranes were designated HyG membrane and HyZIF67G membrane, respectively, and stored in DI water overnight for further evaluation and analysis.

[0332] Inductively coupled plasma optical emission spectrometry (ICP-OES; SPECTRO ARCOS, AMETEK, Inc., USA) was used to determine the elemental composition of samples by measuring the emission spectra of solutions introduced into plasma. This method was operated using argon, air, and nitrogen. ICP-OES was performed 15 min after the start of the filtration experiment to determine the concentration of the constituent element Co of the ZIF-67 nanoparticles in the feed and permeate solutions. At least two measurements were performed on the feed and permeate of the HyZIF67G membrane for analysis, and the average values ​​are presented in this study.

[0333] Atomic force microscopy. Using a microscope equipped with NanoWizard 4 in QI... TM The surface roughness of the films was measured using atomic force microscopy (AFM) in tapping mode (JPK Instruments, Bruker Nano GmbH, Berlin, Germany). AFM was operated in both air and humid atmospheres. Root mean square (RMS) roughness values ​​were calculated for a 5 μm × 5 μm area on the film surface of at least three distinct regions for each film. RMS roughness values ​​are reported as mean ± standard deviation (SD).

[0334] Bradford protein assay. Bradford protein assay was performed using a rapid-start Bradford dye reagent concentrate (Bio-Rad Laboratories GmbH, Feldkirchen, Germany) for protein quantification. 100 mg / L... -1 BSA solution was filtered through a modified membrane for 1 hour. After filtration, 10 mL of BSA-water solution from both the feed and permeate was collected. The absorbance of BSA present in both the feed and permeate in at least five samples was measured at 595 nm using a UV-Vis spectrophotometer (Infinite M200 plate reader, Tecan, Australia). Each sample preparation followed a low BSA concentration curve protocol, where 800 μL of sample was first vortexed with 200 μL of Bradford reagent for a few seconds, and after 5 minutes, the sample was placed on a Costar 48 flat transparent plate for absorbance measurement. BSA concentrations of 1, 5, 10, and 15 mg·L⁻¹ were plotted. -1 The calibration curve of BSA absorbance.

[0335] Pure water permeability measurement. The pure water permeability (PWP) of NF and PAN membranes was evaluated using a stainless steel dead-end filter system with an effective area of ​​0.00134 m². 2 A single membrane (4.13 cm in diameter). A schematic diagram of the experimental filtration equipment is shown in... Figure 1 It is displayed in the middle.

[0336] PWP evaluation of PAN membranes. The same dead-end filtration equipment was used for the PAN membranes. PWP measurements were obtained after a steady-state water flux was achieved at a pressure of 2 bar following a compaction time of 1–2 hours. Permeate was collected at constant intervals of 15 min for at least 1 hour, and measurements were recorded for each membrane. The PWP of the membranes was calculated using equation (3.1).

[0337] This study selected BSA contaminants as model contaminants to examine membrane performance. The membrane's antifouling properties were evaluated using the same dead-end filtration equipment described herein. A 100 mg·L⁻¹ solution was used. - Three types of waste solutions were prepared by dissolving 1BSA contaminants in the following background solutions: 1) water, 2) 20 mM NaCl, and 3) synthetic secondary wastewater (SSWW). The SSWW solutions were prepared based on the composition of actual secondary effluent wastewater at the Shafdan Wastewater Treatment Plant in Israel between July and August 2015, and are depicted in Table 5. Initially, the pristine PAN and modified membrane were pressurized at 2 bar for 1–2 hours to obtain a steady-state flow rate for one of the three background solutions. Filtration experiments were conducted by obtaining approximately 100 L·m³. -2 ·h -1 Starting with the steady-state permeation flux (J0), J0 was recorded at 3-minute intervals for each membrane using each background solution for 30 minutes.

[0338] Next, fouling experiments were conducted on PAN, HyG, and HyZIF67G membranes using BSA / DI water (pH approximately 5.85), BSA / NaCl (pH approximately 6.55), or BSA / SSWW (pH approximately 6.76 and pH approximately 7.43), respectively. Each fouling solution was filtered, and flux (J) was recorded every 3 minutes. t After filtration for 1 hour, the contaminated membrane was washed with DI water for 15 minutes with stirring and without any applied pressure. Finally, background solution was introduced, and the flux (J) of the washed membrane was measured every 3 minutes. c ), lasting for 30 minutes. Calculate the yield in L·m using equation (3.3). -2 ·h -1 Membrane permeation flux in units

[0339]

[0340] Where V is the permeate volume (grams), and A is the effective surface area of ​​the membrane (m²). 2 ), where t is the duration of the filtering interval (h).

[0341] To evaluate the antifouling properties of the PAN-modified membrane, flux recovery was measured using equation (3.4).

[0342]

[0343] Where J0(L·m) -2 ·h -1 J is the permeate flux before membrane fouling. c (L·m -2 ·h -1 () is the permeation flux after cleaning the contaminated membrane.

[0344] Preparation of Synthetic Secondary Wastewater Effluent. A synthetic solution simulating the chemical properties of secondary treatment effluent from the Shafdan Wastewater Treatment Plant in Tel Aviv, Israel, was prepared. The composition of SSWW can be found in Table 3.1. After dissolving the relevant salts, the prepared solution was stirred for at least 6 hours before introducing BSA for pollution experiments.

[0345] Table 5. Composition of the effluent solution from synthetic secondary wastewater (SSWW)

[0346]

[0347]

[0348] Hydrogel-stabilized zeolite imidazole framework-67 nanoparticles on PAN ultrafiltration membranes

[0349] A porous PAN membrane was selected to stabilize in-situ grown ZIF-67 nanoparticles via UV graft polymerization of a methacrylate hydrogel layer, thereby improving the membrane's antifouling properties. The PAN membrane was hydrolyzed with KOH solution, resulting in carboxyl groups on the membrane surface (referred to as the Hy membrane). The Hy membrane was used as the substrate for in-situ grafting of ZIF-67 nanoparticles (referred to as HyZIF67). The surface of the HyZIF67 membrane was further modified with SBMA methacrylate monomers using UV graft polymerization; the resulting membrane was designated HyZIF67G. Figure 17 Stable ZIF-67 nanoparticles were prepared on PAN membranes via UV grafting of zwitterionic methacrylate hydrogel monomers. Hy membranes were UV-grafted using the same monomers to obtain HyG membranes as a reference membrane. Figure 17 ).

[0350] Four film modification schemes were established and compared throughout the study. Each scheme was designed to optimize specific parameters, such as BP initiator concentration, UV irradiation time, and BP incubation time. In schemes 1 and 2, UV irradiation times were maintained at 5 min and 10 min, respectively, while the BP photoinitiator concentration (0.05 M) and BP incubation time (10 min) remained constant. In schemes 3 and 4, BP incubation times were set to 10 min and 30 min, respectively, while the BP photoinitiator concentration (0.1 M) and UV irradiation time (10 min) remained constant. Schemes 1–4 are described in Table 6.

[0351] Table 6. Main parameters used in the preparation of SBMA monomers for UV grafting onto modified HyZIF67 membranes, including BP concentration, BP incubation time, and UV irradiation time.

[0352]

[0353] To confirm the synthesis and formation of ZIF-67 nanoparticles on the PAN membrane surface and the UV grafting of methacrylate copolymers onto the modified membrane, FTIR, EDX, XRD, WCA, SEM, and AFM analyses were performed. More specifically, membrane surface functional groups were confirmed by FTIR, and the presence of characteristic elements and membrane surface crystallinity were investigated using EDX and XRD, respectively. Water contact angle analysis revealed the hydrophilicity of the membrane, while SEM and AFM analyses characterized the surface morphology and roughness of the synthesized nanoparticles and the modified membrane, respectively.

[0354] The presence of organic functional groups on the surface of the original PAN film and the modified film was investigated by ATR-FTIR spectroscopy. In the original PAN film, at 1452 cm⁻¹... -1 and 2240cm -1 The peak at that point is attributed to the nitrile stretching vibration of -C≡N. 71,72,73 And 1741cm -1 The peak at that point is related to carbonyl (C=O) stretching, which may be due to carboxylic acids or esters resulting from additives used during the preparation of commercial PAN films.

[0355] The PAN membrane was hydrolyzed with an alkaline KOH solution; the FTIR spectrum of the Hy membrane showed that the surface nitrile groups were converted to carboxyl groups, which is consistent with the reaction at 1729 cm⁻¹. -1 and 1672cm -1 This is related to the new peak that appeared at 1563cm. -1Another peak appears (as a shoulder peak), which may be related to the NH group in the carboxamide (caused by the alkaline hydrolysis of the PAN membrane converting the -CN group into the -CONH2 group). The spectrum of the hydrolyzed PAN membrane provides strong evidence that -CN was successfully converted into COOH and CONH2 groups during alkaline hydrolysis.

[0356] The FTIR spectrum of the HyG membrane at 1042 cm⁻¹ -1 and 1181cm -1 Peaks were detected at 1668 cm⁻¹, which were attributed to the symmetric and asymmetric vibrations of the sulfonate groups (-SO₃⁻) of the SBMAUV grafted polymer on the Hy film, respectively. Furthermore, a peak was detected at 1668 cm⁻¹. -1 and 1727cm -1 The appearance of the peak may be related to the amide and ester vibrations of C=O. Notably, the peak at 956 cm⁻¹... -1 and 1448cm -1 The peaks at these locations are characteristic of the CN stretching vibrations of the quaternary ammonium groups. The appearance of these peaks confirms that the poly(SBMA-co-MBA) polymer was successfully grafted onto the Hy membrane.

[0357] A film containing in-situ grown ZIF-67 nanoparticles (HyZIF67) at 995 cm⁻¹ -1 1143cm -1 and 1304cm -1 New peaks were observed at 995 cm⁻¹, which are attributed to the stretching and bending of the 2-methylimidazole ligand in the ZIF-67 nanoparticles. More specifically, at 995 cm⁻¹... -1 and 1143cm -1 The peak at 1304 cm⁻¹ can be attributed to CN bending vibration. -1 The peak at that point can be attributed to the aromatic stretching mode of the entire imidazole ring.

[0358] Finally, the FTIR spectrum of the HyZIF67G film confirmed the grafting of poly(SBMA-co-MBA) onto the film coated with ZIF-67 nanoparticles. Compared with the FTIR spectra of HyZIF67 and HyG, the HyZIF67G spectrum exhibited characteristic peaks of both ZIF-67 nanoparticles and the methacrylate polymer. To confirm the presence of ZIF-67 nanoparticles on the film surface, the FTIR spectra of PAN and HyZIF67 films at 400 cm⁻¹ were recorded. -1 and 600cm -1 FTIR spectra between wavenumbers. FTIR spectra at 426 cm⁻¹. -1 A characteristic peak was observed at the point, which is attributed to the Co-N stretching vibration of ZIF-67 nanoparticles on the membrane surface, confirming the presence of ZIF-67 nanoparticles on the HyZIF67 membrane.

[0359] Determination of elemental composition by energy-dispersive X-ray spectroscopy

[0360] The membrane surface was also analyzed using EDX spectroscopy (Table 7). Compared with the original PAN membrane, the hydrolyzed membrane showed an increase in oxygen content, which is consistent with the carboxyl groups obtained from the hydrolysis of nitrile groups in the PAN membrane.

[0361] Compared to the Hy membrane, the presence of sulfur and the increase in oxygen content on the surface of the HyG membrane are due to the sulfonic acid groups of SBMA and its high oxygen content, respectively, which means that the UV grafting of methacrylate SBMA polymer on the Hy membrane was successful.

[0362] Co appeared on the HyZIF67 membrane. 2+ Meanwhile, the oxygen content decreased and the nitrogen content increased, indicating the presence of ZIF-67 nanoparticles on the surface of the HyZIF67 membrane.

[0363] EDX analysis of the HyZIF67G film revealed the presence of both sulfur and cobalt, derived from the methacrylate-SBMA grafted polymer and ZIF-67 nanoparticles, respectively. Therefore, according to... Figure 17 The EDX results further support the success of the membrane modification.

[0364] Table 7. EDX analysis of the surfaces of the original and modified membranes (in mass percentage).

[0365] PAN 80.47 4.9 14.63 Nd Nd Hy 76.35 7.43 16.22 Nd Nd HyG 62.91 17.34 14.50 5.25 Nd HyZIF67 59.89 4.29 29.69 Nd 6.13 HyZIF67G 62.25 16.79 13.13 3.82 1.02

[0366] Film analysis by X-ray diffraction

[0367] The XRD spectra of PAN, Hy, HyG, HyZIF67, and HyZIF67G are shown in Figure 4.5. A set of diffraction planes (001, 005, and 111) of the original PAN film exhibit three major peaks at 2θ of 17.6°, 22.8°, and 25.9°, which is attributed to the crystalline structure of PAN. More specifically, plane (001) is characteristic of the hexagonal structure of PAN, while planes (005) and (111) are attributed to the crystallinity of the PAN polymer chains. Characteristic peaks of the ZIF-67 nanoparticles appear at 2θ = 7.34°, 10.32°, 12.6°, 14.63°, and 16.48°, corresponding to reflections at (011), (002), (112), (022), and (013). The appearance of these peaks indicates that ZIF-67 nanoparticles were successfully synthesized and attached to the film surface, which was confirmed by XRD patterns of the synthesized ZIF-67 crystals after surface modification.

[0368] Wettability of the original and modified membranes

[0369] The effects of different membrane modifications on membrane surface wettability were evaluated using water contact angle measurements. For example... Figure 18As shown, the static water droplet contact angles of PAN, Hy, HyG, HyZIF67, and HyZIF67G membranes were measured. The Hy membrane showed a decrease in water contact angle from 52.2° ± 0.7° for the original PAN membrane to 30.9° ± 2.6° after hydrolysis. The increased surface hydrophilicity can be attributed to the high concentration of carboxyl groups on the membrane surface.

[0370] The HyG membrane exhibits a water contact angle of 39.2° ± 1.9°, which is higher than that of the Hy membrane (30.9° ± 2.6°) but much lower than that of the original PAN. This is attributed to the presence of a hydrophilic grafted hydrogel containing sulfonic acid groups from a zwitterionic SBMA polymer. Therefore, this indicates successful UV grafting of the methacrylate polymer. The properties of both the Hy and HyG membranes imply increased hydrophilicity of the membrane surface.

[0371] Due to the incorporation of hydrophobic ZIF-67 nanoparticles on the membrane surface, the water contact angle of the HyZIF67 membrane increased to 62.1° ± 2.6°. The ZIF-67 nanoparticles also increased the surface roughness, which contributed to the increased water contact angle. On the other hand, the HyZIF67G membrane exhibited a water contact angle of 50.3° ± 3.3°, which is lower than that of the HyZIF67 membrane (and therefore more easily wetted), indicating that the zwitterionic hydrophilic hydrogel successfully coated with ZIF67 nanoparticles.

[0372] Surface morphology

[0373] Figure 19A -F depicts SEM images of the top surfaces of the original PAN, Hy, and HyG films. It can be seen that all surfaces exhibit a smooth morphology. Figure 19D -E shows the surface morphology of ZIF-67 nanoparticles in situ grown on two different HyZIF67 films, in which a layer of ZIF-67 nanoparticles adherently covers the surface. As confirmed by SEM analysis, the size of the in-situ grown ZIF-67 nanoparticles is approximately 1 μm. SEM images of the ZIF-67 nanoparticle layer coated by UV graft polymerization of methacrylate SBMA hydrogel (HyZIF67G film) are also shown. Figure 19F The results show that the methacrylate hydrogel completely covers the ZIF-67 nanoparticles.

[0374] Surface roughness analysis using atomic force microscopy

[0375] To further understand the surface morphology, we performed AFM analysis on the roughness of the pristine and modified membranes. Rrms values ​​were estimated based on AFM images with at least two readings for each modifier, with the scan area for each membrane set to 5 × 5 μm. All AFM analyses were performed in water (wet conditions), except for the HyZIF67 membrane, which was analyzed under dry conditions. The importance of surface roughness stems from its correlation with membrane fouling behavior and its impact on separation performance. The surface roughness of the pristine PAN and Hy membranes was measured, with Rrms values ​​of 24.5 ± 1.8 nm and 18.7 ± 0.9 nm, respectively. Compared to PAN, the Hy membrane exhibited a smoother surface. The HyG membrane showed a smoother roughness with an Rrms value of 20.2 ± 1.8 nm, slightly higher than that of the Hy membrane.

[0376] In comparison, the HyZIF67 film was found to have a significantly higher roughness than the Hy film. MOF deposition on the surface further increased the roughness to 91.8 ± 0.9 nm. However, the HyZIF67G film showed a decrease in surface roughness of 51.9 ± 3.7 nm compared to HyZIF67, highlighting the effect of the presence of the methacrylate hydrogel layer. The surface roughness of the HyZIF67 and HyZIF67G films indicates that the HyZIF67G film derives its combined properties from the grafted methacrylate layer and the formation of ZIF-67.

[0377] Separation performance of modified membranes

[0378] The separation performance of the HyG membrane and the exemplary HyZIF67G membrane of the present invention was investigated by measuring their permeability and antifouling properties using a simulated urban wastewater solution. The pure water permeability of the HyG membrane showed a high PWP of 311.8 ± 5.9 L·m⁻²·h⁻¹·bar⁻¹. The stable HyZIF67G membrane showed a slight decrease, exhibiting a PWP of 205.4 ± 3.7 L·m⁻²·h⁻¹·bar⁻¹.

[0379] Furthermore, cobalt in the permeate was analyzed to examine the stability of ZIF-67 nanoparticles on the modified HyZIF67G membrane. The cobalt ion concentrations in the feed and permeate during PWP filtration experiments with the HyZIF67G membrane were determined by ICP analysis. Our findings indicate that the cobalt concentration in the feed is below the detection limit of ICP, and the cobalt concentration in the permeate is relatively low. 2+ The concentration of cobalt is very low: 82 ppb. This low concentration of cobalt indicates good stability of the ZIF-67 nanoparticle layer on the surface of the grafted HyZIF67G film.

[0380] Antifouling performance of modified membranes during secondary treatment of municipal wastewater filtration

[0381] Secondary wastewater effluent contains high organic loads, which seriously impacts the environment. Furthermore, treating it using membrane technology leads to severe organic pollution problems. To investigate membrane treatment of secondary wastewater, in our study, we simulated a synthetic secondary wastewater solution containing organic pollutants to mimic real wastewater effluent. Antifouling experiments were conducted by filtration of a BSA-containing SSWW solution through a membrane using a dead-end filter. The composition of the simulated SSWW solution was as described above. Antifouling experiments were performed by filtering BSA solutions from DI water, BSA solutions in a 20 mM NaCl solution (with the same ionic strength as SSWW), and BSA solutions from the SSWW solution.

[0382] Filtration tests were conducted on the original PAN membrane and the HyZIF67G membrane. Initially, the filtration of BSA in the water was tested; 100 mg·L⁻¹ was introduced. -1 A BSA aqueous solution was used as the feed solution, and a single filtration experiment lasted for 2 hours, followed by washing with DI water for 15 minutes with stirring but without pressure. Upon contact with the BSA solution, the PAN membrane exhibited a significant decrease in permeation flux, while the HyZIF67G membrane experienced a relatively smaller decrease in permeation flux.

[0383] Further antifouling experiments were conducted by filtering BSA from a 20 mM NaCl solution using both PAN and HyZIF67G membranes. Similarly, after filtering a 20 mM NaCl solution containing 100 ppm BSA, the PAN membrane exhibited a significant decrease in permeate flux, while the HyZIF67G membrane showed improved antifouling performance and a smaller decrease in permeate flux compared to the original PAN membrane. In summary, regarding final flux and antifouling performance, the HyZIF67G membrane prepared using scheme 3 (Table 6) demonstrated superior performance with an FRR of 99.5% compared to the original membrane. Furthermore, the HyZIF67G membranes prepared according to schemes 1, 2, and 4 were compared with the HyZIF67G membrane prepared using scheme 3 (Table 6), and their performance was comparable, with FRRs ranging from 90% to 99%.

[0384] To evaluate the BSA antifouling performance of the modified membranes when filtering SSWW effluent (Table 5), the permeation flux of PAN, HyG, and HyZIF67G membranes was examined and measured when filtering 100 ppm of BSA contaminants in SSWW solutions with pH values ​​of 6-7. Figure 20AThe results showed that both HyG and HyZIF67G membranes exhibited improved antifouling properties when filtering BSA / SSWW solutions, as these membranes (I) reduced the rate of initial flux decline and (II) increased the steady-state flux at the end of fouling operation compared to the original unmodified membrane. While HyZIF67G and HyG membranes showed similar antifouling performance, HyG exhibited a 15% reduction in PWP compared to HyZIF67G membranes, indicating that HyZIF67G membranes demonstrated the best performance in terms of overall transportability and antifouling properties. Figure 20B The antifouling performance of PAN, HyG, and HyZIF67G membranes at pH values ​​of 7.15-7.7 was demonstrated.

[0385] The BSA rejection value of the HyZIF67G membrane (scheme 3) was measured using Bradford assay. The BSA concentrations in the feed and permeate after filtration were 100 mg / L. -1 and 3.334 mg·L -1 Based on equation (4.1), the BSA rejection rate of the HyZIF67G membrane is 96.7%.

[0386]

[0387] Where C P and C F These represent the concentrations of BSA in the permeate and feed solution, respectively.

[0388] The surface morphology of the membrane after the BSA / SSWW antifouling filtration experiment was examined using SEM, indicating that the membrane surface morphology was different; SEM micrographs ( Figure 21A -B) shows several aggregates on the surfaces of the PAN, Hy, and HyG membranes. The pristine PAN membrane exhibits significant contaminant adhesion. In contrast, the HyZIF67G membrane shows negligible contaminant adhesion, demonstrating its excellent antifouling properties.

[0389] HyZIF67G membrane provides long-lasting antifouling performance for secondary municipal wastewater treatment.

[0390] The dead-end configuration of the experimental tank was used for long-term antifouling performance testing; the permeate flux of PAN and HyZIF67G membranes was tested in a long-term BSA filtration experiment in SSWW solution (Table 5). A total of 10 cycles of the fouling experiment were conducted, with each cycle lasting 2 hours. Before starting the filtration cycle, SSWW was used as feed and filtration was carried out for an additional 0.5 hours while permeability was measured, and the permeate flux was calibrated to 100 L·m³. -2 ·h -1Then, each cycle began with filtering an SSWW solution containing 100 ppm BSA, recording the permeation flux every 3 minutes for 1 hour. Afterward, the BSA / SSWW solution was discarded, and the fouled membrane was washed with DI water for 15 minutes with stirring but without pressure. Then, the SSWW solution was filtered for 15 minutes, with flux measurements continued for an additional 0.5 hours. Figure 22 ).

[0391] based on Figure 22 The original PAN membrane exhibited a significant decrease in flux after 10 cycles of filtering SSWW contaminant solution containing BSA; measurements showed that the flux recovery rate of the PAN membrane was 57.4%, compared to 73.2% for the HyZIF67G membrane. This further demonstrates the influence of surface functionalization of grafted SBMA incorporating ZIF-67 nanoparticles on the membrane's fouling tendency.

[0392] After 10 filtration cycles of synthetic secondary wastewater effluent containing bovine serum albumin, the HyZIF67G membrane exhibited improved antifouling properties, with a flux recovery rate of 73.2% compared to 57.4% of the original membrane.

[0393] After each filtration cycle, it was observed that hydraulic cleaning removed reversible contaminants, while irreversible contaminants accumulated on the membrane surface, leading to a decline in membrane performance. Compared to the original membrane (54 L·m⁻¹), [the performance deteriorated]. -2 ·h -1 Compared to the HyZIF67G membrane, the steady-state flux after 10 cycles of filtration experiments showed a higher permeability (73 L·m³). -2 ·h -1 This further demonstrates that BSA contaminants have the lowest affinity for the HyZIF67G membrane surface and can provide ideal antifouling performance.

[0394] Compared to commercial membranes, the HyZIF67G membrane of this invention exhibits high overall performance, with a good PWP (47.6 L·m⁻¹) at 2 bar when using SSWW solution. -2 ·h -1 ·bar -1 The high flux recovery rate (89%) indicates that the addition of ZIF-67 nanoparticles to the HyG membrane demonstrates excellent antifouling performance during wastewater treatment.

[0395] Therefore, the exemplary membrane of the present invention (HyZIF67G) was characterized by FTIR, EDX, and XRD, confirming the presence of ZIF-67 nanoparticles and zwitterionic methacrylate hydrogel on the membrane surface. Compared with the original PAN membrane, the HyZIF67G membrane exhibits higher hydrophilicity.

[0396] After 10 filtration cycles of synthetic secondary wastewater effluent doped with bovine serum albumin, the HyZIF67G membrane exhibited improved antifouling properties: the flux recovery rate after 10 filtration cycles was 73.2%, significantly higher than the 57.4% of the original membrane. Furthermore, the BSA rejection rate of the HyZIF67G membrane was approximately 97%. SEM images of the fouled membrane showed that the amount of contaminants adhering to the surface of the HyZIF67G membrane after filtration was negligible compared to modified membranes or PAN membranes without ZIF-67 nanoparticles, indicating that the HyZIF67G membrane possesses excellent antifouling properties.

[0397] Therefore, the membranes disclosed herein may be used for high-efficiency UF filtration in water treatment applications, such as treating recycled secondary municipal wastewater effluent, oil / water separation, whey protein concentration, and dye / salt separation.

[0398] Although the invention has been described in conjunction with specific embodiments, many alternatives, modifications, and variations will be apparent to those skilled in the art. Therefore, the invention is intended to include all alternatives, modifications, and variations falling within the spirit and broad scope of the appended claims.

[0399] All publications, patents, and patent applications mentioned in this specification are incorporated herein by reference in their entirety, to the same extent that each individual publication, patent, or patent application is specifically and individually incorporated herein by reference. Furthermore, any reference cited or designated in this application should not be construed as an admission that such reference is prior art to the present invention. The use of section headings should not be construed as inherently limiting.

Claims

1. A membrane comprising a polymer membrane in contact with a coating, the coating comprising a plurality of nanoparticles and a hydrogel containing a crosslinked hydrophilic polymer, the nanoparticles being metal-organic framework (MOF) nanoparticles, the crosslinked hydrophilic polymer being selected from polyacrylate or polymethacrylate; wherein the crosslinked hydrophilic polymer is grafted and polymerized to the outer surface of the polymer membrane; the membrane is water-permeable, and wherein the membrane is prepared by the following steps: Step 1: Surface chemical modification of the polymer film is performed by hydrolysis, carboxylation, or amination; Step 2: In-situ growth of MOF nanoparticles on the surface of the surface chemically modified polymer film; Step 3: Surface graft polymerization of hydrophilic monomers such as acrylate or methacrylate with a crosslinking agent to form the hydrogel on the membrane surface.

2. The membrane according to claim 1, wherein the polymethacrylate is poly(2-(N-3-sulfopropyl-N,N-dimethylammonium)methacrylate).

3. The membrane according to claim 1, wherein the polymer membrane is a polyacrylonitrile membrane.

4. The membrane according to claim 1, wherein the crosslinking agent is N,N'-methylenebisacrylamide (MBA).

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