Hydrophilic graft stabilization of layers of crystalline framework structures on polymeric membranes, preparation method and use thereof - Patents.com

Abstract

A water-permeable coated substrate is disclosed that includes a polymeric substrate in contact with a coating that includes a plurality of particles and a crosslinked polymer. Uses of the coated substrate, particularly for water filtration, are also disclosed.

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of priority to U.S. Provisional Patent Application No. 63 / 193,077, filed May 26, 2021, the contents of which are incorporated by reference in their entirety as if fully set forth herein.

[0002] FIELD OF THEINVENTION The present invention, in some embodiments thereof, relates to coated hydrophilic polymeric substrates and their use, for example in filtration membranes. [Background technology]

[0003] Produced water (PW) is a by-product generated in large quantities by extraction processes in the oil and gas industry. PW typically contains organic and inorganic components and is harmful to the environment. It must therefore be treated using efficient and economical methods before release to minimize environmental damage, or reclaimed for industrial or agricultural use as non-potable water, especially in water-stressed regions.

[0004] Surface modification is favorable for mitigating membrane fouling in PW treatment because of its easy processing and negligible environmental impact, which improves the water flux and oil removal efficiency of the resulting membrane.

[0005] The actual industrial application of membranes for PW treatment requires membranes with good performance and stability. Therefore, there is a need to develop membranes with excellent fouling resistance that provide filtration while maintaining high water flux values ​​and oil removal efficiency. Various crystalline framework structure nanoparticles, such as ZIF-8 nanoparticles, have recently emerged as promising functional materials to modify membrane surface properties for water treatment applications due to their unique framework structure, extremely high specific surface area, tunable size, thermal and chemical stability, facile synthesis protocol, and low production cost. However, the integration of crystalline framework structure nanoparticles into polymer membranes is challenging due to the limited stability of these nanoparticles as a separation layer during filtration. Therefore, hydrophilic membranes modified with crystalline framework structure nanoparticles that exhibit fouling resistance, high water flux, and high oil removal efficiency during filtration of PW wastewater are therefore needed. Summary of the Invention

[0006] The present invention, in some embodiments thereof, relates to a hydrophilic polymeric substrate in contact with a composite coating comprising a plurality of crystalline framework structure nanoparticles or microparticles and a crosslinked polymer, and its use in, for example, filtration membranes.

[0007] According to an aspect of some embodiments of the present invention, there is provided a membrane comprising a polymeric membrane in contact with a coating layer comprising a plurality of crystalline framework structures (CFS) and a hydrogel comprising a crosslinked hydrophilic polymer, wherein the membrane is water permeable.

[0008] In one embodiment, the cross-linked hydrophilic polymer comprises a polymer selected from polyacrylates or polymethacrylates.

[0009] In one embodiment, the CFS comprises nanoparticles.

[0010] In one embodiment, the nanoparticles are selected from covalent organic framework (COF) nanoparticles and metal-organic framework (MOF) nanoparticles.

[0011] In one embodiment, the outer surface of the polymer membrane is chemically modified.

[0012] In one embodiment, the chemical modification is with a plurality of surface groups selected from amino and carboxy.

[0013] In one embodiment, the polymethacrylate comprises poly(2-(N-3-sulfopropyl-N,N-dimethylammonium)ethyl methacrylate).

[0014] In one embodiment, the cross-linked hydrophilic polymer is characterized by a degree of cross-linking of about 5%.

[0015] In one embodiment, the film is characterized by one of: (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°; (iv) a water contact angle that is less than the water contact angle of an untreated polymer film.

[0016] In one embodiment, the film is characterized by a water contact angle that is about 13% less than the water contact angle of an untreated polymer film.

[0017] In one embodiment, the membrane has a resistance of about 450 L*m -2 h -1 bar -1 99%, a flux recovery of about 99%, or any combination thereof.

[0018] In one embodiment, the polymeric membrane is selected from an ultrafiltration membrane, a nanofiltration membrane, and a microfiltration membrane.

[0019] In another aspect, a coated substrate is provided that includes a polymeric substrate in contact with a coating comprising a plurality of particles and a crosslinked polymer, the crosslinked polymer is a hydrophilic polymer including an acrylate-based polymer, an exterior surface of the coating is characterized by a water contact angle of less than about 70°, the crosslinked polymer is characterized by a degree of crosslinking of 1-20%, the plurality of particles is characterized by an average particle size of 1 nm-20 μm, and the coated substrate is water permeable.

[0020] In one embodiment, the crosslinked polymer is in the form of a matrix and the plurality of particles are embedded within or coated by the matrix.

[0021] In one embodiment, the crosslinked polymer is characterized by a degree of crosslinking of 2-10%.

[0022] In one embodiment, the polymeric substrate is in the form of a porous water-permeable film.

[0023] In one embodiment, the water permeability is at least 10 L*m -2 h -1 bar -1 The pores contain sufficient porosity to support a pure water flow of a flux of .

[0024] In one embodiment, the porous water permeable film is characterized by an average pore size of 1 to 10 μm.

[0025] In one embodiment, the coating is in the form of a continuous layer characterized by a dry thickness of between 50 nm and 20 μm.

[0026] In one embodiment, the exterior surface of the coating is characterized by a negative zeta potential.

[0027] In one embodiment, the outer surface of the coating is characterized by a surface roughness of 10-40 nm.

[0028] In one embodiment, the weight / weight (w / w) ratio of particles to crosslinked polymer in the coating is from 1:10 to 10:1.

[0029] In one embodiment, the polymer substrate comprises a surface-modified thermoplastic polymer.

[0030] In one embodiment, the surface modified polymer is characterized by a water contact angle that is at least 10° less than a similar polymer substrate comprising an untreated thermoplastic polymer.

[0031] In one embodiment, the surface-modified polymer is characterized by a water contact angle of less than 70°.

[0032] In one embodiment, the thermoplastic polymer is selected from the group consisting of polyacrylonitrile, polyethersulfone, polysulfone, cellulose acetate, polyvinylidene fluoride, polybenzimidazole, inherently microporous polymers, and polyolefins, including any combination and any copolymer thereof.

[0033] In one embodiment, the exterior surface of the coating is characterized by a water contact angle of from about 5° to about 50°.

[0034] In one embodiment, the particles are crystalline framework structure (CFS) particles.

[0035] In one embodiment, the CFS particles include zeolites, metal-organic frameworks (MOFs), and covalent organic frameworks (COFs).

[0036] In one embodiment, the exterior surface of the coating is characterized by reduced microbial adhesion thereto, as compared to a similar substrate without the coating.

[0037] In one embodiment, at least 90% of the exterior surface is in contact with the coating.

[0038] In another aspect, a membrane is provided that includes the coated substrate of the present invention.

[0039] In one embodiment, the water filtration membrane is characterized by a thickness of 10 to 1000 μm.

[0040] In one embodiment, the membrane is characterized by a pore size between 2 nm and 100 nm, and optionally, the membrane is an ultrafiltration membrane.

[0041] In one embodiment, the membrane is characterized by a flux recovery of at least 70%.

[0042] In one embodiment, the membrane is characterized by at least 95% oil rejection.

[0043] In one embodiment, the membrane retains at least 90% of its initial particle content during successive water treatment cycles.

[0044] Unless otherwise defined, all technical and / or scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this invention belongs.Although methods and materials similar or equivalent to those described herein can be used to carry out or test embodiments of the present invention, exemplary methods and / or materials are described below.In case of conflict, the patent specification, including definitions, shall prevail.In addition, the materials, methods, and examples are illustrative only and are not necessarily intended to be limiting.

[0045] Some embodiments of the present invention are described herein, by way of example only, with reference to the accompanying drawings, in which it is emphasized that, with particular reference to the details of the drawings, the details are given by way of example and for illustrative discussion of embodiments of the present invention, in which regard the description, together with the drawings, will make apparent to those skilled in the art how embodiments of the present invention may be practiced. [Brief description of the drawings]

[0046] [Figure 1]1 is a scheme showing the dead-end filtration setup, in which 1: pressure regulator, 2: pressure gauge, 3: stirred cell, 4: supported membrane, 5: magnetic stirrer, and 6: permeate collection vessel. [Diagram 2] FIG. 1 is a scheme illustrating the preparation of hydrostable ZIF-8 modified PAN membranes: (1) hydrolysis to obtain hydrolyzed PAN membrane (Hy), (2) in situ growth of ZIF-8 nanoparticles on the Hy membrane to obtain HyZif membrane, and (3) redox grafting of SBMA / MBA onto the Hy and HyZif membranes to obtain HyG and HyZifG membranes, respectively. [Figure 3A-B] 3A shows the FTIR spectrum of the membrane of the present invention (FIG. 3A) and the XPS wide spectrum of the membrane tested (FIG. 3B). The presence of characteristic functional groups on the membrane confirmed the modification. [Figure 4A-B] 4A and 4B are graphs showing the XRD spectra of the membrane of the present invention (FIG. 4A) and ZIF-8 nanoparticles (FIG. 4B). The characteristic peaks of ZIF-8 particles were shown on the relevant spectra of HyZif and HyZifG membranes (FIG. 4A). [Figure 5A-B] 5A and 5B are images showing EDX elemental mapping of the cross section (FIG. 5A) and surface (FIG. 5B) of a HyZifG film. The elemental map appearance of Zn confirms the presence of ZIF-8 nanoparticles on the film. [Figure 6] 1 is a bar graph showing water contact angle values ​​measured on dry films by the sessile drop method. [Figure 7A-B] 7A and 7B are AFM micrographs (FIG. 7A) and bar graphs (FIG. 7B) showing the surface roughness of the membranes measured by AFM. The RRMS values ​​are provided next to the name of each membrane. The scan area is 5×5 μm. At least three readings from each membrane were measured and the RRMS values ​​were reported as the mean ± SD. FIG. 7A shows an AFM micrograph of an exemplary HyZifG membrane with an RRMS value of 24.6±2.0 nm. [Figure 8] 1 is a bar graph showing the pure water permeability of the prepared membranes. Higher permeability values ​​were recorded for the modified membranes compared to the untreated PAN membrane. [Figure 9]Figure 1 shows the graphs of anti-fouling filtration experiments with PAN, Hy, HyG, and HyZifG membranes using simulated oilfield PW (see solution composition in Table 1). The tests were carried out under a stable initial flux (100 L m-2 h-1) by adjusting the transmembrane pressure (0.1-0.3 bar). The average transmembrane pressures (bar) of the different membranes were 0.25 (PAN), 0.18 (Hy), 0.15 (HyG), and 0.22 (HyZifG). In the figure, W indicates the water filtration step, and PW indicates the simulated oilfield PW filtration step. [Figure 10] Scheme showing the anti-fouling mechanism of HyZifG membranes in the treatment of oilfield PW. The inset shows the proposed structure for the chemical stability of the ZIF-8 layer via coordination interactions between negatively charged sulfonic acid groups and positively charged ZIF-8 nanoparticles. [Figure 11A-D] SEM micrographs of PAN (11A, 11A1), Hy (11C, 11C1), HyG (11A, 11A1), and HyZifG (11D, 11D1) membranes before and after fouling in oilfield PW treatment. Figures 11A, 11B, 11C, and 11D show SEM micrographs of PAN, Hy, HyG, and HyZifG membranes before fouling. Figures 11A1, 11B1, 11C1, and 11D1 show SEM micrographs of PAN, Hy, HyG, and HyZifG membranes after fouling. The HyZifG membrane showed negligible adhesion of foulants to the surface, while the foulant adhesion to the surface of the untreated PAN membrane was significantly higher. The results support the good anti-fouling performance of the HyZifG membrane. The scale bars in all panels represent 5 μm. [Figure 12] FIG. 1 shows FTIR spectra of fresh and used (after fouling experiment) HyZifG membranes, illustrating the stability of the modification layer on the membrane surface. [Figure 13] 1 is a graph showing zeta potential analysis (in 1 mM KCl solution) of PAN, Hy, and HyG membranes. [Figure 14A-C]14A-C are SEM micrographs of PAN (FIG. 14A), HyZif (FIG. 14B), and HyZifG (FIG. 14C) membranes showing the surface morphology of the different membranes disclosed herein compared to untreated PAN membrane. [Figure 15A-D] Micrographs, FTIR and XRD spectra of the synthesized COF-300 nanoparticles. Figures 15A-B are SEM images of COF-300 nanoparticles showing their oblong shape. Figure 15C is the FTIR spectrum of COF-300 nanoparticles showing their characteristic peaks at 1625 cm-1 (attributed to the imine C=N stretch) and 2926 cm-1 (attributed to the alkene CH stretch from the imine), thus confirming their successful synthesis. Figure 15D is the XRD pattern of COF-300 nanoparticles. [Figure 16] 1 is a micrograph showing an SEM image of COF-300 nanoparticles deposited on a hydrolyzed PAN film. [Figure 17] FIG. 14 Scheme showing the preparation of hydrogel-stabilized ZIF-67 modified PAN membranes: (step 1) hydrolysis, (step 2) in situ growth of ZIF-67 nanoparticles, and (step 3) UV graft polymerization of SBMA-co-MBA. [Figure 18] 1 is a bar graph showing water droplet contact angles for untreated PAN membranes and modified membranes of the present invention. [Figure 19A-F] SEM analysis of the surface morphology of (Figure 19A) the PAN membrane, (Figure 19B) the Hy membrane, (Figure 19C) the HyG membrane, (Figures 19D-E) the HyZIF67 membrane, and (Figure 19F) the HyZIF67G membrane. [Figure 20A-B] 20A and 20B are graphs showing the anti-fouling performance of untreated PAN, HyG (10 min UV), and HyZIF67G membranes, as measured by filtering 100 ppm BSA in synthetic secondary wastewater (SSWW) solutions of pH 6.4-6.7 (FIG. 20A) and pH 7.2-7.7 (FIG. 20B). [Figure 21A-B] SEM analysis of the surface morphology of PAN (FIG. 21A) and HyZIF67G (FIG. 21B) membranes after BSA / SSWW fouling (as disclosed in Example 4). [Figure 22] Untreated PAN membrane filtering BSA from synthetic secondary wastewater (SSWW) solution [ka] and HyZIF67G membranes [ka] Long-term anti-fouling filtration experiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0047] The present invention, in some embodiments thereof, relates to a coated polymeric substrate comprising a coating layer comprised of crystalline framework structure nanoparticles and a hydrophilic cross-linked polymer (e.g., in the form of a hydrogel). Further, the present invention, in some embodiments thereof, relates to the use of the coated polymeric substrate as a water filtration membrane.

[0048] Before describing at least one embodiment of the invention in detail, it should be understood that the invention is not necessarily limited in its application to the details set forth in the following description or illustrated by way of examples, as the invention is capable of other embodiments or of being practiced or carried out in various ways.

[0049] The present invention is based, inter alia, on the recognition that crosslinked hydrophilic acrylic polymers can be utilized to stably entrap crystalline framework structure particles (e.g., COF and / or MOF nanoparticles) to obtain a stable composite membrane suitable for water filtration. In some embodiments, the crosslinked hydrophilic acrylic polymer is applied on top of a crystalline framework structure nanoparticle layer 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 (as reflected in water contact angle), chemical and / or mechanical stability, thermal stability, sufficient water permeability, and significantly reduced fouling properties, compared to uncoated (or untreated) 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).

[0050] As used herein, the term "chemical stability" is intended to refer to the property of the coating polymer substrate of the present disclosure to be able to withstand and perform under harsh operating and cleaning conditions, such as high back pressure, strong oxidizing agents, bases, and acids (typically applied in cleaning industrial filtration membranes), high densities of microorganisms (e.g., biological foulants), or, in the context of thermal stability, high temperatures.

[0051] According to an aspect of the present disclosure, there is provided a coated substrate comprising a polymeric substrate in contact with a coating, the coating comprising a plurality of particles and a crosslinked polymer, the crosslinked polymer being a hydrophilic water-wettable polymer characterized by a degree of crosslinking between 1-20%, the plurality of particles being characterized by an average particle size between 1 nm and 20 μm, and the coated substrate being water permeable.

[0052] 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°, including any range therebetween. As used herein, the term "water contact angle" of a crosslinked polymer refers to a physical property of the surface of the crosslinked polymer in the form of a film or 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.

[0053] In some embodiments, the crosslinked polymer is derived from a water soluble monomer, hi some embodiments, the crosslinked polymer is derived from a monomer having 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, 1-100 g / L, 10-100 g / L, 10-80 g / L, 10-60 g / L, 20-100 g / L, 20-90 g / L, 20-200 g / L, 10-200 g / L, including any range therebetween.

[0054] In some embodiments, the crosslinked polymer comprises a hydrophilic thermoplastic polymer crosslinked via 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-based polymer, including any salts and any copolymers thereof. In some embodiments, the hydrophilic thermoplastic polymer is substantially devoid of polyamino acids and / or polydopamine. In some embodiments, the hydrophilic thermoplastic polymer consists essentially of an acrylate-based polymer, including any salts and any copolymers thereof.

[0055] In some embodiments, the term "hydrogel" as used herein refers to a non-Newtonian fluid (or semi-solid) that comprises a supramolecular structure of cross-linked polymer molecules (e.g., a hydrophilic polymer such as polyacrylate or polymethacrylate) and water. In some embodiments, the supramolecular structure physically binds the water molecules. In some embodiments, the supramolecular structure is in the form of a three-dimensional network of cross-linked polymer chains.

[0056] In some embodiments, the hydrogel or polymer matrix disclosed herein is substantially devoid 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 with polymer chains distributed in a pattern therein (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) a substantially uniform pore size (e.g., the average distance between two adjacent polymer chains), (ii) a substantially uniform pore density or distribution pattern within the hydrogel or polymer matrix, or both (i) and (ii).

[0057] In some embodiments, the acrylate-based polymer comprises polyacrylate, its ester, alkylated polyacrylate (e.g., polymethacrylate), polyacrylamide, including any copolymer or any mixture thereof. A variety of acrylate polymers are known in the art. In some embodiments, the acrylate-based polymer is or comprises a graft polymer. In some embodiments, the acrylate-based polymer is or comprises an in-situ graft polymer.

[0058] In some embodiments, the term "acrylate-based polymer" refers to a non-crosslinked polymer, as defined below. In some embodiments, the acrylate-based polymer has Formula 1: [ka] wherein n represents an integer, X represents O, OH, N, NH, or NH2 as permitted by valence, and R1 and R each independently represent absent, H, or a substituent selected from alkyl (linear or branched), hydroxyalkyl, haloalkyl, aminoalkyl, cycloalkyl, glycol, polyethyleneoxide, dimethylaminoethyl, trimethylaminoethyl, dimethylaminoethyl-3-sulfopropyl, cyano, nitro, carboxy, hydroxy, halo, amino, or any combination thereof. In some embodiments, n represents an integer ranging from 2 to 100,000, including any range therebetween.

[0059] In some embodiments, the acrylate-based polymer is an uncharged polymer. In some embodiments, the acrylate-based polymer is an ionizable polymer (e.g., capable of undergoing protonation or deprotonation in water, resulting in a positively or negatively charged polymer, e.g., at a pH in the range of 5-8). In some embodiments, the acrylate-based polymer is an intrinsically charged polymer (e.g., a negatively and / or positively charged polymer). In some embodiments, the acrylate-based polymer is a zwitterionic polymer.

[0060] In some embodiments, the acrylate-based polymer is poly(2-(N-3-sulfopropyl-N,N-dimethylammonium)ethyl methacrylate), including any salt or any copolymer thereof.

[0061] In some embodiments, the crosslinked polymer is characterized by a degree of crosslinking of 1-20%, 1-10%, 1-8%, 1-7%, 2-20%, 2-10%, 2-8%, 1-6%, 1-5%, 1-4.5%, 2-5%, 1-2.5%, 2.8-20%, 2.8-10%, 5-20%, 5-10%, 5.5-20%, 5.5-10%, 5.5-8%, including any range therebetween. In some embodiments, the degree of crosslinking is such that it provides a mesh capable of retaining particles within the coating and permitting water permeability of the coated substrate as disclosed herein. Without wishing to be bound by a particular theory, it is hypothesized that a degree of crosslinking of 10%, or 20% or more significantly reduces the water permeability of the coated substrate, thus rendering the coated substrate less suitable for use as a membrane.

[0062] In some embodiments, the crosslinked polymer comprises multiple polymer chains covalently bonded to each other via a crosslinker. In some embodiments, the polymer chains comprise thermoplastic polymer chains (also used 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 entangled matrix made up of randomly distributed polymer chains. In some embodiments, the polymer chains are randomly distributed within the matrix. In some embodiments, the matrix is ​​substantially devoid of aligned or oriented polymer chains. In some embodiments, the matrix is ​​substantially devoid of aligned or oriented polymer chains in a particular direction. In some embodiments, the thermoplastic polymers comprising the polymer matrix are chemically identical polymers. In some embodiments, the polymer matrix comprises multiple chemically distinct polymers. In some embodiments, the polymer matrix comprises a mixture of chemically distinct polymer species. In some embodiments, the polymer matrix is ​​in the form of a hydrogel comprising water molecules attached to the polymer chains. In some embodiments, the polymer matrix is ​​hydrophilic. In some embodiments, the polymer matrix is ​​swellable. In some embodiments, the coatings described herein can absorb 10-1000%, 10-100%, 50-1000%, 100-1000%, 10-500% water based on the initial dry weight of the coated substrate of the present invention, including any range therebetween.

[0063] In some embodiments, the crosslinker is or includes a bifunctional molecule (e.g., bisacrylate) that can react with the monomer (and / or the growing polymer chain) to covalently crosslink the polymer chain. One skilled in the art will understand that upon crosslinking, the crosslinker undergoes chemical modification. Thus, the crosslinked polymer includes polymer chains covalently bonded via a chemically modified (or derivatized) crosslinker. A non-limiting example of a crosslinker is N'-methylenebisacrylamide.

[0064] In some embodiments, the polymer chains contact the particles described herein, thereby forming 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 separate layers. In some embodiments, one or more layers of the coating independently comprise the crosslinked polymer and particles described herein. In some embodiments, one or more layers of the coating is in the form of a composite material.

[0065] In some embodiments, the particles are embedded within the polymer matrix. In some embodiments, the particles are homogeneously distributed within the polymer matrix. In some embodiments, the particles are surrounded by the polymer matrix. In some embodiments, the particles are physisorbed and / or chemisorbed on or within the polymer matrix.

[0066] 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 on and attached to the substrate. In some embodiments, the first layer and / or coating substantially covers at least one surface of the substrate. In some embodiments, substantially covering includes at least 80%, at least 90%, at least 95%, at least 97%, at least 99%, at least 99.9% surface coverage of the substrate, including any range therebetween.

[0067] In some embodiments, the second layer is on top of and bonded to the first layer. In some embodiments, the second layer is in the form of a coating on the first layer. 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 first layer from collapsing. In some embodiments, the second layer prevents the first layer from peeling off the substrate. In some embodiments, the second layer stabilizes the first layer. In some embodiments, the second layer (or crosslinked polymer) provides the particles with sufficient physical stability for use of the coated substrate as a filtration membrane (e.g., a water filtration membrane or UF membrane). In some embodiments, the second layer (or crosslinked polymer) provides physical stability to the coated substrate (e.g., by substantially preventing the coating from collapsing and / or the particles from leaking therefrom), where the physical stability is sufficient for implementation of the coated substrate as a membrane. In some embodiments, the physical stability is between 10 and 1000 L m, including any range therebetween. -2 h -1 Bar -1 , 100~1000L m -2 h -1 Bar -1 , 100~2000L m -2 h -1 Bar -1 In some embodiments, the coating and substrate are water permeable. In some embodiments, the coated substrate is sufficient to support a water flux in the range of 10 to 1000 L m, including any range therebetween. -2 h -1 Bar -1 , 100~1000L m -2 h -1 Bar -1 , 100~2000L m -2 h -1 Bar -1 The water flow rate is configured to support a water flux in the range of 100 .mu.m to 100 .mu.m.

[0068] In some embodiments, the crosslinked polymer (or second layer) provides a barrier property to the coated substrate, thereby substantially increasing its stability. In some embodiments, the crosslinked polymer (or second layer) provides a barrier property that substantially maintains the integrity of the coating. In some embodiments, the crosslinked polymer (or second layer) provides a barrier property that substantially prevents leakage of particles therefrom. In some embodiments, a stable coated substrate is substantially free of coating collapse and / or substantially maintains the initial content of particles in the coating. In some embodiments, the crosslinked polymer (or second layer) substantially maintains the initial content of particles in the coating. In some embodiments, the physical stability is sufficient to maintain at least 80%, at least 90%, at least 95%, at least 97%, at least 99% of the initial content of particles in the coating upon successive (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. The integrity of the coating can be assessed by determining the concentration of components of the particles in the filtrate (e.g., when MOF particles are implemented, a significant increase in the concentration of metal cations in the filtrate indicates instability of the coating).

[0069] In some embodiments, the term "bound" refers to any non-covalent bond or interaction, such as electrostatic bonds, dipole-dipole interactions, van der Waals interactions, ionotropic interactions, hydrogen bonds, hydrophobic interactions, pi-pi stacking, London forces, etc. In some embodiments, the non-covalent bond or interaction is a stable bond or interaction, where stable is as described herein.

[0070] In some embodiments, the crosslinked polymer is in the form of a mesh (e.g., a 2D or 3D mesh structure). In some embodiments, the mesh is porous and the average pore size of the mesh is the same as or smaller than the average size of the particles disclosed herein. In some embodiments, the average pore size of the mesh is at least 10%, at least 100%, at least 500%, at least 1000%, at least 10,000% smaller than the average size of the particles, including any ranges therebetween. In some embodiments, the average pore size of the mesh is 1 nm to 1 μm, 1 to 100 nm, 5 to 100 nm, 10 to 100 nm, 1 to 500 nm, 10 to 500 nm, 100 to 1000 nm, including any ranges therebetween.

[0071] In some embodiments, the term "porous" as used herein refers to a material characterized by porosity, e.g., containing pores, holes, voids, or spaces within its network. However, the porous layer may optionally contain additional material in the spaces between the polymer chains, so long as at least a portion of the volume of the voids is not filled by the additional material. In some embodiments, the additional material comprises particles disclosed herein.

[0072] In some embodiments, porosity is measured as the fraction, between 0 and 1, of the volume of the coating that consists of voids (or pores).

[0073] In some embodiments, the porosity of the coating is between 0.1 and 0.99.

[0074] 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.

[0075] In some embodiments, the coating is water permeable. In some embodiments, the porosity of the coating is sufficient to provide the coating with water permeability. In some embodiments, the porosity of the coating is sufficient to support water flux at the fluxes disclosed herein.

[0076] The term "porosity" refers to a measure of the void space in a material, and in some embodiments is defined as the ratio of the free or pore volume of a material to the total volume of the material, as determined by well-known physical measurements such as N2 adsorption / desorption.

[0077] In some embodiments, the coating and / or coating substrate of the present invention is a composite material. In some embodiments, the coating is a solid coating. In some embodiments, the coating and / or coating substrate of the present invention is in the form of a layered composite. As used herein, a "composite material" is a material made from two or more constituent materials that have significantly different chemical or physical properties that, when combined, create a material with properties different from the individual elements.

[0078] In some embodiments, a composite refers to a substantially homogenous material that cannot be easily separated into individual components (e.g., particles and crosslinked polymers of the present invention). In some embodiments, the composite is substantially free of phase separation or collapse (also referred to herein as a "stable" composite). In some embodiments, the composite is substantially devoid of a multi-layer structure. In some embodiments, the coating is a single layer coating.

[0079] In some embodiments, the term "layer" refers to a material of substantially uniform thickness. 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.

[0080] In some embodiments, the coating is in the form of a separate layer attached to the substrate. In some embodiments, the particles and / or the crosslinked polymer are attached to the substrate. In some embodiments, the particles are attached to the substrate via electrostatic interactions and / or coordination bonds.

[0081] In some embodiments, the coating has a thickness 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 10 μm, 10 μm to 1000 μm, 100 μm to 1000 μm, including any range therebetween. In some embodiments, the thickness of the coating refers to the dry thickness. In some embodiments, the coating is in the form of a layer characterized by a substantially uniform thickness. In some embodiments, the term "thickness" refers to the median of the shortest distance from one side of the coating layer to the other side of the coating layer (e.g., from the inner surface to the outer surface of the coating). Typically, the thickness is measured in an orthogonal direction.

[0082] 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 substantially composed of a crosslinked polymer. In some embodiments, the inner surface of the coating is substantially composed of particles disclosed herein. In some embodiments, the outer surface of the coating is characterized by either (i) a negative zeta potential, (ii) a surface roughness of 10-40 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°, including any range therebetween. In some embodiments, the exterior surface of the coating is further characterized by a water contact angle of about 5° to about 50°, about 5° to about 60°, about 5° to about 10°, about 10° to about 50°, about 10° to about 40°, about 5° to about 30°, about 5° to about 40°, about 10° to about 30°, about 30° to about 60°, including any range therebetween. As used herein, "water contact angle" refers to the angle that water forms with the exterior surface of the coating where the free surface of a stationary liquid contacts the horizontal surface of the coating.

[0083] Typically, but not exclusively, to measure contact angle, a drop of water is formed on the tip of a hypodermic needle attached to a screw syringe. The syringe is fixed to a stand, which reduces irregularities caused by manual dropping. The substrate is then raised using the Y control of the stage until it touches the drop. The xy translation of the stage then brings the drop into the field of view and focus of the microscope, and an image is acquired. The contact angle is calculated by methods known in the art.

[0084] In some embodiments, the exterior surface of the coating is characterized by a negative zeta potential in the range of -1 to -60 mV, -1 to -20 mV, -5 to -30 mV, -5 to -20 mV, -5 to -10 mV, -10 to -30 mV, -10 to -60 mV, -1 to -40 mV, -1 to -50 mV, -5 to -50 mV, -5 to -60 mV, -5 to -40 mV, -1 to -20 mV, -20 to -30 mV, including any range therebetween (e.g., when measured at a pH in the range of 4 to 9). In some embodiments, the exterior surface of the coating is characterized by a more negative zeta potential compared to the untreated (uncoated) substrate, where more is at least 1 mV, at least 5 mV, at least 10 mV more negative zeta potential, including any range therebetween.

[0085] In some embodiments, the exterior surface of the coating is characterized by a surface roughness of 10-40 nm, 10-100 nm, 1-40 nm, 1-100 nm, 10-30 nm, 10-20 nm, 20-100 nm, including any range therebetween.

[0086] The term "roughness" as used herein relates to irregularities in a surface texture. The irregularities are the peaks and valleys of the surface.

[0087] In some embodiments, the roughness value is calculated by AA (arithmetic average) and RMS (root mean square). The AA method uses the absolute value of the deviation in the averaging procedure, while the RMS method utilizes the squared value of the deviation in the averaging process.

[0088] In some embodiments, the coatings disclosed herein consist essentially of the crosslinked polymers and particles disclosed herein.

[0089] In some embodiments, the weight / weight (w / w) ratio of particles to crosslinked polymer in the coating is from 1:10 to 1:10,000, 1:10 to 10:1, 1:10 to 1:1000, 1:10 to 1:100, 1:1 to 1:100, 1:1 to 1:100, 1:10 to 1:50, 1:50 to 1:1000, 1:50 to 1:10,000, including any range therebetween. , 1:100~1:1000, 1:100~1:10,000, 100:1~1:1, 50:1~1:1, 10:1~1:1, 80:1~1:1, 80:1~10:1, 100:1~10:1, 100:1~20:1, 100:1~50:1, 50:1~30:1, 30:1~10:1, 10:1~5:1, 5:1~1:1.

[0090] In some embodiments, the w / w concentration of the particles in the coated substrate is 0.001-30%, 0.01-30%, 0.1-30%, 0.1-20%, 0.1-10%, 0.1-5%, 1-30%, 1-20%, 5-30%, 5-20%, 1-5%, 0.5-10%, 0.5-20%, 0.01-1%, 1-10%, including any range therebetween.

[0091] 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 sufficient porosity 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 devoid of amorphous particles or amorphous materials. 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%, at least 99.5% by weight (or atomic percentage) of the metal in the CFS 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%, at least 99.5% by weight (or atomic percentage) of the metal in the coated substrate of the present invention 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%, at least 99.5% by weight of the CFS in the coated substrate of the present invention is in a crystalline state. In some embodiments, the presence of particles (and / or crystallinity) in the coated substrate can be determined by XRD, FT-IR. Exemplary XRD / FT-IR spectra of coated substrates are presented herein.

[0092] Exemplary particles include, but are not limited to, COF-102, COF-103, COF-105, COF-108, and COF-300 particles, zeolite-like imidazole structure (ZIF) particles such as ZIF-L, ZIF-8, ZIF-67, or any combination thereof.Other porous crystalline particles (e.g., CFS, or any other organic, inorganic, or metal-organic porous crystalline particles) are well known in the art.

[0093] In some embodiments, the particles are characterized by an average particle size of 1 nm to 20 μm, 1 nm to 10 μm, 1 nm to 1 μm, 1 nm to 5 μm, 10 nm to 20 μm, 10 nm to 10 μm, 10 nm to 1 μm, 10 nm to 5 μm, 1 nm to 100 nm, 1 nm to 1000 nm, 1 nm to 500 nm, 10 nm to 500 nm, 500 nm to 20 μm, 500 nm to 10 μm, 500 nm to 5 μm, 500 nm to 3 μm, including any range therebetween.

[0094] In some embodiments, the particles are bonded to the substrate to obtain a dense layer (e.g., a first layer), in some embodiments, the first layer is characterized by a thickness of 100 nm to 10 μm, 500 nm to 10 μm, 700 nm to 10 μm, 1 to 10 μm, 1 to 5 μm, 500 nm to 5 μm, 100 nm to 5 μm, 100 nm to 1 μm, 500 nm to 3 μm, including any range therebetween.

[0095] In some embodiments, the particles are stably attached to the substrate, thus forming a 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, non-covalent, and / or coordinate bonds.

[0096] In some embodiments, the particles are stably bound 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 comprises a plurality of surface groups including carboxy, amino, amide, hydroxy, or any combination thereof. In some embodiments, the chemical modification comprises an ionizable group, where ionizable is as described herein. In some embodiments, the chemical modification provides the substrate with a negative surface charge. In some embodiments, the chemically modified substrate is characterized by a more negative zeta potential compared to an untreated substrate, where more negative zeta potential is at least 1 mV, at least 5 mV, at least 10 mV, at least 20 mV, at least 30 mV, including any range therebetween.

[0097] In some embodiments, the chemically modified substrate is characterized by an isoelectric point at a pH value of 3.5 to 5.5, or about 4.

[0098] In some embodiments, the chemical modification provides binding affinity to the outer surface of the substrate, and the binding affinity is sufficient to facilitate attachment of the particles thereto. In some embodiments, the chemically modified substrate is characterized by significantly enhanced binding affinity to the particles compared to the untreated substrate. In some embodiments, the binding affinity of the chemically modified substrate is enhanced by at least 2, 10, 100, 1000, or 10000 times compared to the untreated substrate.

[0099] In some embodiments, the substrate consists essentially of a thermoplastic polymer. In some embodiments, the substrate comprises a hydrophobic polymer. In some embodiments, the thermoplastic polymer is a hydrophobic polymer (e.g., characterized by a water contact angle of 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 of less than 90°, or between 1° and 90°). In some embodiments, the thermoplastic polymer is selected from fluorinated polymers such as polyvinylidene fluoride, polysulfones, polyols, polyethersulfones, polyamides, polyesters, cellulose acetate, nitrocellulose, polybenzimidazole, PVP, inherently microporous polymers, polyolefins, including any copolymers and any mixtures thereof. In some embodiments, polyolefins include polyethylene, polypropylene, polymethylpentene (PMP), polybutene-1 (PB-1), ethylene-octene copolymers, stereoblock polypropylene, propylene-butane copolymers, low density polyethylene (LDPE), linear low density polyethylene (LLDPE), very low density polyethylene (VLDPE), very low density polyethylene (ULDPE), medium density polyethylene (MDPE), high density polyethylene (HDPE), including any copolymers and any mixtures thereof.

[0100] In some embodiments, the polyol comprises polyvinyl alcohol (PVA), ethylene vinyl alcohol copolymer (EVOH), or both.

[0101] Exemplary intrinsic microporosity polymers are known in the art and include, but are not limited to, PIM-1, PIM-EA-TB, PIM-PY, PIM-EA-TB-H2, and PIM-7, or any combination thereof.

[0102] In some embodiments, the intrinsically microporous polymer has a pore size range of about 1 nm to about 10 nm, and / or about 700 to 1000 nm, including any range therebetween. 2 ·g -1It is characterized by a surface area of

[0103] 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°, 10-90°, 10-70°, 5-70°, 10-60°, 15-60°, 20-60°, 20-70°, 30-70°, 15-40°, 15-50°, 15°-30°, including any range therebetween.

[0104] In some embodiments, the surface-modified substrate is characterized by a water contact angle that is at least 5°, at least 10°, at least 20°, or at least 30° lower compared to the untreated substrate. In some embodiments, the untreated substrate comprises the same thermoplastic polymer, and the exterior surface of the untreated substrate is unmodified. In some embodiments, the untreated substrate is an unmodified substrate that consists essentially of unmodified (or untreated) thermoplastic polymer.

[0105] In some embodiments, the substrate comprises a hydrophilic thermoplastic polymer selected from polyacrylonitrile, polyethersulfone, nitrocellulose, including any copolymers and any mixtures thereof. In some embodiments, the terms "hydrophilic" and "water-wettable" are used interchangeably herein. Additional 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°, including any range therebetween.

[0106] In some embodiments, the substrate is a porous substrate. In some embodiments, the substrate comprises a plurality of pores characterized by a pore size of 2-100 nm, 10-100 nm, 5-100 nm, 20-100 nm, 30-100 nm, 2-50 nm, 50-100 nm, 5-80 nm, including any range therebetween. In some embodiments, the substrate comprises a plurality of pores characterized by an average pore size of 5 nm to 300 nm, e.g., 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, including any value or range therebetween.

[0107] 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 values ​​and ranges therebetween. In some embodiments, the porous substrate is in the form of a membrane (e.g., a filtration membrane or an ultrafiltration membrane) configured to support water flux as described herein.

[0108] In some embodiments, the disclosed coating substrate has a coating density of 0.05 g / cm 3 ~2g / cm 3 In some embodiments, the disclosed coated substrates are characterized by a density in the range of 0.1 g / cm 3 ~1g / cm 3 In some embodiments, the disclosed coated substrates are characterized by a density in the range of 0.2 g / cm 3 ~0.8g / cm 3 It is characterized by a density in the range of

[0109] In some embodiments, the disclosed coating substrates have a coating density of 0.05 g / cm, including any value and range therebetween. 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 2 g / cm 3 It is characterized by its density.

[0110] In some embodiments, the disclosed coated substrates are characterized by substantially the same mechanical strength, thermal stability, and / or water permeability as the untreated substrate, hi some embodiments, the water permeability of the coated substrate is reduced by 10-70%, 10-50%, 10-30%, 10-20% compared to the untreated substrate, including any value and range therebetween.

[0111] The term "mechanical strength" as used herein means overall desirable strength, such as breaking strength, stiffness, flexibility, and / or toughness.

[0112] 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 about 150° C., up to about 200° C., up to about 300° C., or up to about 400° C., including any values ​​and ranges therebetween.

[0113] film In another aspect, an article is provided that includes the coated substrate disclosed herein. Exemplary articles include, but are not limited to, agricultural equipment, containers, agricultural equipment, architectural elements, water treatment devices and components thereof, organic waste treatment devices and components thereof, microelectronic devices, microelectromechanical devices, photovoltaic devices, or microfluidic devices.

[0114] In some embodiments, the article is a filtration membrane.

[0115] In some embodiments, the article is a water filtration membrane as defined throughout this specification for the selective separation of chemical species (e.g., nitric acid, and / or organic lipophilic molecules such as organic solvents, oils, hydrocarbons, etc.), particularly for the selective purification of contaminated water (e.g., produced water).

[0116] As demonstrated in the Examples section below, the filtration membranes exhibit improved oil rejection and flux recovery compared to untreated membranes. Additionally, exemplary membranes of the present invention are substantially free of biofouling during extended operation.

[0117] In some embodiments, the disclosed membranes lack an additional polymer layer (such as a polymer on the outer surface of a supporting substrate, or coating).

[0118] In some embodiments, the membrane can withstand some applied pressure or force, as described below.

[0119] In some embodiments, the term "filtration membranes," as used throughout this specification, refers to membranes that are characterized by their molecular weight cutoff and / or their retention values ​​for inorganic salts and / or small organic molecules.

[0120] In some embodiments, the molecular weight cutoff 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, about 2 to about 300 kDa, about 2 to about 200 kDa, including any range therebetween.

[0121] In some embodiments, the disclosed membrane is a microfiltration, or ultrafiltration, or nanofiltration membrane.As further demonstrated in the Examples section below, the unique morphology and composition of the disclosed membrane (e.g., the coating substrate of the present invention) can facilitate high membrane permeation rates.Specifically, the inventors have successfully implemented the above-disclosed coating on an ultrafiltration membrane, as illustrated in the Examples section.Therefore, it is hypothesized that the disclosed coating can be suitable for application to polymeric ultrafiltration membranes, and even nanofiltration membranes, and optionally microfiltration membranes.

[0122] In some embodiments, a "high permeation rate" is at least about 10 to at least about 600 L / m per bar of application, including any range therebetween. 2 h, or about 10 to about 600 L / m per bar of application 2 h, or about 30 to about 600 L / m per bar of application 2 h, e.g., at least about 10 L / m per bar of application 2 h, at least about 30 L / m per bar of application 2 h, at least about 60 L / m per bar of application 2 h, at least about 100 L / m per bar of application 2 h, at least about 150 L / m per bar of application 2 h, at least about 200 L / m per bar of application 2 h, at least about 250 L / m per bar of application 2 h, at least about 300 L / m per bar of application 2 h, at least about 350 L / m per bar of application 2h, at least about 400 L / m per bar of application 2 h, at least about 450 L / m per bar of application 2 h, at least about 500 L / m per bar of application 2 h, at least about 448 L / m per bar of application 2 h permeation rate.

[0123] In some embodiments, the disclosed membranes are characterized by substantially the same or increased water permeability compared to an untreated membrane (e.g., a similar membrane without a coating). In some embodiments, the disclosed membranes are characterized by increased water permeability compared to an untreated membrane, where the increase is about 5%, about 10%, about 13%, about 15%, about 20%, about 30%, about 40%, about 50% increase, including any range therebetween.

[0124] In some embodiments, the disclosed membranes are water filtration membranes characterized by a thickness of 50-1000 μm, 50-200 μm, 200-500 μm, 200-1000 μm, 10-1000 μm, 10-100 μm, 1-1000 μm, 1-100 μm, 10-500 μm, 100-1000 μm, 100-500 μm, 500-1000 μm, including any range therebetween.

[0125] In some embodiments, the disclosed membranes are ultrafiltration membranes characterized by pore sizes between 2-100 nm, 10-100 nm, 5-100 nm, 20-100 nm, 30-100 nm, 2-50 nm, 50-100 nm, 5-80 nm, including any range therebetween.

[0126] In some embodiments, the disclosed membranes are characterized by a flux recovery 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%, 70-95%, 70-99%, 70-98.5%, including any range therebetween.

[0127] In some embodiments, the disclosed membranes are characterized by an oil removal 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%, at least 99.99%, including any ranges therebetween.

[0128] In some embodiments, the disclosed membrane is stable (e.g., substantially retains initial particle content, is substantially free of collapse, separation of coating from substrate, fouling, and substantially maintains any of its physical properties such as dimensions, porosity, permeability, elasticity, selectivity, oil removal) upon its exposure to successive water treatment cycles (e.g., 2, 3, 5, 7, 10, 20, 50, 100, 2-100, 2-10, 2-20, 2-50, including any ranges therebetween), up to 300°C, up to 200°C, up to 150°C, up to 100°C, or any one of temperatures of -30-200°C, 0-200°C, -30-300°C, -30-150°C, 0-300°C, including any ranges or values ​​therebetween). In some embodiments, the term "stable" refers to the ability of the membrane to maintain its structural, physico-mechanical, and / or chemical integrity. In some embodiments, a membrane is said to be stable if there is a substantial absence of degradation and / or dissociation, where substantial is as described herein.

[0129] While studying the activity of the membranes of the present disclosure as described herein, the inventors surprisingly discovered that the membranes exhibit high anti-fouling activity and therefore may be beneficially incorporated into filtration systems where such activity is desirable.

[0130] As used herein, "anti-biofouling activity" or "anti-fouling activity" refers to the ability to inhibit (prevent), reduce, or delay biofilm formation or microbial attachment to the exterior surface of a coated substrate (e.g., a membrane disclosed herein).

[0131] The term "biofilm" as used herein refers to an aggregate of living cells attached to each other and / or immobilized on a surface as a colony. The cells are often embedded within a matrix of autocrine extracellular polymeric substances (EPS), also called "slime", which is a sticky polymeric mixture of nucleic acids, proteins, and polysaccharides.

[0132] In the context of this embodiment, the living cells that form the biofilm may be cells of unicellular microorganisms (prokaryotes, archaea, bacteria, eukaryotes, protists, fungi, algae, euglena, protozoa, dinoflagellates, apicomplexa, trypanosoma, amoeba, etc.), or cells of multicellular organisms, in which case the biofilm may be considered as a colony of cells (as in the case of unicellular organisms) or as a subform of tissue.

[0133] In the context of this embodiment, the cells are of microbial origin, and the biofilm is a biofilm of microorganisms, such as bacteria and fungi. The cells of microorganisms that grow in biofilms are physiologically different from the "planktonic" cells of the same organism, which in contrast are single cells that can float or swim in a liquid medium. Biofilms can go through several life cycle steps, including initial attachment, irreversible attachment, one or more maturation stages, and detachment. The phrase "anti-biofilm formation activity" refers to the ability of a substance to affect the prevention of the formation of biofilms of bacteria, fungi, and / or other cells, and / or to affect the reduction of the rate of accumulation of biofilms of bacteria, fungi, and / or other cells on the outer surface of a membrane.

[0134] In some embodiments, the biofilm comprises bacterial cells, hi some embodiments, the bacterial cells are of a bacteria selected from the group consisting of all gram-positive and gram-negative bacteria.

[0135] In some embodiments, the Gram-negative biofilm forming bacteria may be selected from the group of species including, but not limited to, Proteus, Enterobacter, Citrobacter, Shigella, Escherichia, Edwardsiella, Aeromonas, Plesiomonas, Moraxella, Alcaligenes, and Pseudomonas.

[0136] As demonstrated below, membranes as described herein have been shown to exhibit anti-biofilm activity and thus can prevent, delay, or reduce the formation or mass of biofilms. Thus, membranes as described herein can be effectively incorporated into filtration systems that include anti-biofilm formation activity where such activity is beneficial (e.g., required or desired).

[0137] As used herein, the term "prevent" in relation to biofilm formation indicates that biofilm formation is essentially abolished or the appearance of biofilm is 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%, including any values ​​and ranges therebetween, as compared to an untreated membrane.

[0138] Alternatively, prevent means that the appearance of biofilm is reduced, for example, by at least 99.9%, 95%, 93%, 90%, 80%, 70%, 60%, 30%, 15%, 10%, or 5%, as compared to an untreated membrane. Methods for determining the level of appearance of biofilm are known in the art.

[0139] In some embodiments, the amount of biofilm formed by bacterial cells on an article (e.g., a filtration membrane) or a filtration system comprising the same in the presence of a growth medium for 24 hours is greater than or equal to 10 5 In some embodiments, this is less than 10 4 Less than 10 CFU 3 Less than 10 CFU 2In some embodiments, the membranes of the invention exposed to successive filtration cycles have a maximum of 10 CFU per square centimeter of membrane surface. 5 CFU, up to 10 4 CFU, up to 10 3 CFU, up to 10 2 CFU, up to 10 CFU, or even lower.

[0140] As described throughout this specification, such articles of manufacture 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.

[0141] According to some embodiments of the present invention, the compositions presented herein are packaged in packaging material and identified in or on the packaging material for use in reducing or preventing the formation of biofilms and / or disrupting biofilms in or on a substrate.

[0142] In some embodiments, the disclosed membranes are sterilized and used in aseptic applications.

[0143] Alternatively, the disclosed membranes can be incorporated into any of the articles of manufacture described herein during manufacture of the article of manufacture.

[0144] In one embodiment of the present invention, a method is provided for reducing the concentration of contaminants in a fluid (e.g., contaminated water, PW, wastewater, etc.) comprising contacting the fluid with an article (e.g., a filtration membrane) of the present disclosure. In some embodiments, the contacting comprises performing filtration (e.g., in a continuous mode by circulation of the contaminated water through the article, or in a batch mode). In some embodiments, the contacting is repeated one or more further times.

[0145] According to another aspect of the present invention, there is provided a method for treating contaminated water, comprising contacting the contaminated water with the membrane of the present invention under suitable conditions, thereby reducing the concentration of one or more contaminants in the contaminated water. In some embodiments, the method for treating contaminated water thereby obtains treated water. In some embodiments, the terms "treated water" and "reclaimed water" are used interchangeably herein.

[0146] In some embodiments, reclaimed water refers to water suitable for recycling. It should be clear that the term "reclaimed water" encompasses water that at least meets the regulatory standards in a particular jurisdiction, so that the reclaimed water can be recycled or disposed of in a reservoir or natural water source, such as a lake, pond, sea, ocean, etc. In particular, the regulatory standards specify maximum amounts of common contaminants (e.g., metals, heavy metals, nitrogen species, phosphorus species, etc.). Specifically, the term "reclaimed water" may encompass water with different thresholds of contaminants, such as phosphorus species.

[0147] In some embodiments, contaminated water, as used herein, comprises wastewater from dairy farms, olive oil mills, wineries, pig farms, cattle farms, 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 comprises dairy wastewater.

[0148] In some embodiments, the contaminated water comprises drinking water or a source thereof, the drinking water or a source thereof being derived from a river, lake, reservoir, pond, stream, groundwater, spring, surface water, and / or seawater, or a combination thereof.

[0149] In some embodiments, the method is for reducing a contaminant concentration in the contaminated water. In some embodiments, reducing 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%, of the initial contaminant concentration in the contaminated water, including any ranges therebetween. In some embodiments, reducing includes eliminating 70-99.7%, 80-99.7%, 90-99.7%, 95-99.7%, 70-99.99%, of the initial contaminant concentration in the contaminated water, including any ranges therebetween. In some embodiments, reducing includes completely eliminating the contaminant from the contaminated water (e.g., to obtain a treated water having a contaminant concentration below its detection limit).

[0150] The disclosed method is effective in treating one or more contaminant components, such as inorganic water contaminants (e.g., phosphorus species such as phosphate, diphosphate, polyphosphate, nitrogen species such as nitrate, nitrogen oxide, nitrous acid, etc.), organic components such as hydrocarbons, and / or organic-based components. Examples of organic and hydrocarbon contaminant components that may be treated according to the present invention include, but are not limited to, petroleum (crude oil including top-water crude oil), organic acids such as benzoic acid, aromatic components including ketones, aldehydes, phenols, etc., organic materials containing heteroatoms such as nitrogen, sulfur, and halogens such as chloride, pigments, polymeric materials including but not limited to carbohydrates (e.g., polysaccharides), proteins, fatty acids, and mixtures thereof. Other contaminants that may be treated with the present process include, but are not limited to, materials that are active ingredients or products of manufacturing processes, or by-products of processes, such as, but not limited to, cyanides or hydrazines, organic insecticides, herbicides, sewage pollution, and pesticides resulting from soil leaching due to continuous water use in agriculture, e.g., fruit and vegetable production, especially in arid to semi-arid climates.

[0151] definition As used herein, the term "alkyl" refers to an aliphatic hydrocarbon, including straight chain and branched chain groups. In some embodiments, the alkyl group has 1-20, 1-10, 1-5, 5-10, 10-15, 15-20 carbon atoms, including any range therebetween.

[0152] In some embodiments, the alkyl group has 21-100 carbon atoms, more preferably 21-50 carbon atoms. Whenever a numerical range, for example "21-100", is stated herein, it is implied that the group, in this case the alkyl group, may contain up to 100 carbon atoms, such as 21 carbon atoms, 22 carbon atoms, 23 carbon atoms, etc. In the context of the present invention, a "long chain alkyl" is an alkyl having at least 20 carbon atoms in its backbone (the longest path of consecutive covalently bonded atoms). Thus, a short chain alkyl has 20 or fewer backbone carbons. The alkyl may be substituted or unsubstituted as defined herein.

[0153] The term "alkyl," as used herein, also includes saturated or unsaturated hydrocarbons, and thus, this term further includes alkenyls and alkynyls.

[0154] The term "alkenyl" refers to an unsaturated alkyl, as defined herein, having at least two carbon atoms and at least one carbon-carbon double bond. The alkenyl may be unsubstituted or substituted by one or more substituents, as described above.

[0155] The term "alkynyl" refers to an unsaturated alkyl group, as defined herein, having at least two carbon atoms and at least one carbon-carbon triple bond. The alkynyl group may be unsubstituted or substituted with one or more substituents, as described above.

[0156] The term "cycloalkyl" refers to an all-carbon monocyclic or fused ring (i.e., rings that share adjacent pairs of carbon atoms) group in which one or more of the rings does not have a fully conjugated pi-electron system. Cycloalkyl groups can be substituted or unsubstituted as described herein. Furthermore, the term "cycloalkyl" further encompasses heterocyclyl rings, as described herein.

[0157] The term "aryl" refers to an all-carbon monocyclic or fused polycyclic (i.e., rings which share adjacent pairs of carbon atoms) group having a completely conjugated pi-electron system. Aryl groups can be substituted or unsubstituted as indicated herein.

[0158] The term "alkoxy" refers to both an --O-alkyl and an --O-cycloalkyl group, as defined herein.

[0159] The term "aryloxy" refers to -O-aryl, as defined herein.

[0160] Each of the alkyl, cycloalkyl, and aryl groups in the general formulas herein can be substituted with one or more substituents, each of which can be, independently, for example, halide, alkyl, alkoxy, cycloalkyl, nitro, amino, hydroxyl, thiol, thioalkoxy, carboxy, amido, aryl, and aryloxy, depending on the group substituted and its position in the molecule. Additional substituents are also contemplated.

[0161] The terms "halide," "halogen," or "halo" refer to fluorine, chlorine, bromine, or iodine.

[0162] The term "haloalkyl" refers to an alkyl group, as defined herein, further substituted with one or more halide.

[0163] The term "haloalkoxy" refers to an alkoxy group, as defined herein, further substituted with one or more halide.

[0164] The terms "hydroxyl" or "hydroxy" refer to an --OH group.

[0165] The term "mercapto" or "thiol" refers to a -SH group.

[0166] The term "thioalkoxy" refers to both an --S-alkyl group, and an --S-cycloalkyl group, as defined herein.

[0167] The term "thioaryloxy" refers to both an --S-aryl and an --S-heteroaryl group, as defined herein.

[0168] The term "amino" refers to a -NR'R'' group, with R' and R'' as described herein.

[0169] The term "heterocyclyl" refers to a monocyclic or fused ring group having one or more atoms such as nitrogen, oxygen, and sulfur in the ring(s). The ring may also have one or more double bonds. However, the ring does not have a completely conjugated pi-electron system. Representative examples are piperidine, piperazine, tetrahydrofuran, tetrahydropyran, morpholino, etc.

[0170] The term "carboxy" or "carboxylate" refers to the group -C(O)OR', where R' is hydrogen, alkyl, cycloalkyl, alkenyl, aryl, heteroaryl (bonded through a ring carbon), or heterocyclyl (bonded through a ring carbon), as defined herein.

[0171] The term "carbonyl" refers to the group --C(O)R', where R' is as defined above.

[0172] The above terms also include thio derivatives thereof (thiocarboxy and thiocarbonyl).

[0173] The term "thiocarbonyl" refers to a -C(S)R' group, where R' is as defined above.

[0174] A "thiocarboxy" group refers to a -C(S)OR' group, where R' is as defined herein.

[0175] A "sulfinyl" group refers to a -S(O)R' group, where R' is as defined herein.

[0176] A "sulfonyl" or "sulfonate" group refers to a -S(O)2R' group, where R' is as defined herein.

[0177] A "carbamyl" or "carbamate" group refers to an --OC(O)NR'R'' group, where R' is as defined herein and R'' is as defined for R'.

[0178] A "nitro" group refers to a -NO2 group.

[0179] The term "amide" as used herein includes C-amide and N-amide.

[0180] The term "C-amide" refers to a -C(O)NR'R'' terminal group or a -C(O)NR'- linking group, as these terms are defined above, where R' and R'' are as defined herein.

[0181] The term "N-amido" refers to an -NR"C(O)R' terminal group or an -NR'C(O)- linking group, as these terms are defined above, where R' and R" are as defined herein.

[0182] The term "carboxylic acid derivatives" as used herein includes carboxy, amide, carbonyl, anhydride, carbonate, and carbamate.

[0183] A "cyano" or "nitrile" group refers to a --CN group.

[0184] The terms "azo" or "diazo" refer to an --N.dbd.NR' terminal group or an --N.dbd.N- linking group, as these terms are defined above, with R' as defined above.

[0185] The term "guanidine" refers to the -R'NC(N)NR''R''' terminal group or the -R'NC(N)NR''- linking group, as these terms are defined above, where R', R'', and R''' are as defined herein.

[0186] As used herein, the term "azido" refers to the group --N3.

[0187] The term "sulfonamide" refers to a -S(O)2NR'R'' group, with R' and R'' as defined herein.

[0188] The term "phosphonyl" or "phosphonate" refers to an -OP(O)-(OR')2 group with R' as defined above.

[0189] The term "phosphinyl" refers to a -PR'R'' group, with R' and R'' as defined above.

[0190] The term "alkylaryl" refers to an alkyl, as defined herein, substituted by an aryl, as described herein. An exemplary alkylaryl is benzyl.

[0191] The term "heteroaryl" refers to a monocyclic (e.g., C5-C6 heteroaryl ring) or fused ring (i.e., rings sharing adjacent pairs of atoms) group having one or more atoms, such as nitrogen, oxygen, and sulfur, in the ring(s) and further having a fully conjugated pi-electron system. In some embodiments, the terms "heteroaryl" and "C5-C6 heteroaryl" are used interchangeably herein. Non-limiting examples of heteroaryl groups include pyrrole, furan, thiophene, imidazole, oxazole, thiazole, pyrazole, pyridine, pyrimidine, quinoline, isoquinoline, and purine. Heteroaryl groups can be substituted or unsubstituted by one or more substituents, as described above. Representative examples are thiadiazole, pyridine, pyrrole, oxazole, indole, purine, and the like.

[0192] As used herein, the terms "halo" and "halide," which are considered interchangeable herein, refer to an atom of the halogens, i.e., fluorine, chlorine, bromine, or iodine, also referred to herein as fluoride, chloride, bromide, and iodide.

[0193] The term "haloalkyl" refers to an alkyl group, as defined above, further substituted with one or more halide.

[0194] As used herein, the term "substituted" or "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 "substituent" refers to any of (C0-C6)alkyl-aryl, (C0-C6)alkyl-heteroaryl, (C0-C6)alkyl-(C3-C8)cycloalkyl, optionally substituted C3-C8 heterocyclyl, 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, SON(R)2, -NHNR2, -NNR, C1-C6 haloalkyl, optionally substituted C3-C8 heterocyclyl, 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, SON(R), -NHNR2, -NNR, C1-C6 haloalkyl, optionally substituted C3-C8 heterocyclyl, and optionally containing one or more substituents selected from 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.

[0195] As used herein, the term "C1-C6 alkyl", including any C1-C6 alkyl related compound, refers to any straight or branched alkyl chain containing 1-6, 1-2, 2-3, 3-4, 4-5, 5-6 carbon atoms, including any range therebetween. In some embodiments, C1-C6 alkyl includes any of methyl, ethyl, propyl, butyl, pentyl, isopentyl, hexyl, and tert-butyl, or any combination thereof. In some embodiments, C1-C6 alkyl as described herein further includes an unsaturated bond, the unsaturated bond being located at the 1, 2, 3, 4, 5, or 6 position of the C1-C6 alkyl.

[0196] The term "(C1-C6)haloalkyl" refers to a C1-C6 alkyl group, as defined herein, further substituted with one or more halides, such as chloro, bromo, and / or fluoro. In some embodiments, the C1-C6 haloalkyl is selected from the group including -CX3, -CHX2, -CH2X, -CH2-CX3, -CH2-CHX2, -CH2-CH2X, where X represents a halo group. In some embodiments, the C1-C6 haloalkyl is selected from the group including -CF3, -CHF2, -CH2F, -CH2-CF3, -CH2-CHF2, -CH2-CH2F.

[0197] Each R′ and R independently represents hydrogen or an optionally substituted C1-C 10 Alkyl, optionally substituted C3-C 10 Cycloalkyl, optionally substituted C3-C 10 It is selected from the group comprising heterocyclyl, optionally substituted heteroaryl, optionally substituted aryl, or a combination thereof.

[0198] General rules: As used herein, the term "about" or "approximately" refers to ±10%.

[0199] The terms "comprises," "comprising," "includes," "including," "having" and their conjugations mean "including but not limited to."

[0200] The term "consisting of" means "including and limited to."

[0201] The term "consisting essentially of" means that a composition, method, or structure may include additional components, steps, and / or moieties, but only if the additional components, steps, and / or moieties do not materially alter the basic and novel characteristics of the claimed composition, method, or structure.

[0202] The word "exemplary" is used herein to mean "serving as an example, instance, or illustration." Any embodiment described as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments and / or does not necessarily exclude the incorporation of features from other embodiments.

[0203] The word "optionally" is used herein to mean "is provided in some embodiments and is not provided in other embodiments." Any particular embodiment of the invention may include multiple "optional" features unless such features are inconsistent.

[0204] As used herein, the singular forms "a," "an," and "the" include plural references unless the context clearly dictates otherwise. For example, the term "a compound" or "at least one compound" can include multiple compounds, including mixtures thereof.

[0205] Throughout this application, various embodiments of the present invention may be presented in a range format. It should be understood that the description in range format is merely for convenience and brevity and should not be construed as an inflexible limitation on the scope of the present invention. Thus, the description of a range should be considered to have all possible subranges specifically disclosed and individual numerical values ​​within that range. For example, a description of a range such as 1-6 should be considered to have specifically disclosed subranges such as 1-3, 1-4, 1-5, 2-4, 2-6, 3-6, and individual numbers within that range, for example, 1, 2, 3, 4, 5, and 6. This applies regardless of the breadth of the range.

[0206] Whenever a numerical range is given herein, it is intended to include any stated numerical value (fractional or integer) within the given range. The phrases "ranging / ranges between" a first given number and a second given number, and "ranging / ranges from" a first given number to a second given number, are used interchangeably herein and are intended to include the first and second given numbers and all fractions and integers therebetween.

[0207] As used herein, the term "method" refers to methods, means, techniques, and procedures for accomplishing a given task, including, but not limited to, methods, means, techniques, and procedures that are known to or readily developed by practitioners of the chemical, pharmacological, biological, biochemical, and medical arts from known methods, means, techniques, and procedures.

[0208] As used herein, the term "treating" includes arresting, substantially inhibiting, slowing or reversing the progression of a condition, substantially ameliorating the clinical or cosmetic symptoms of a condition, or substantially preventing the appearance of clinical or cosmetic symptoms of a condition.

[0209] It will be understood that certain features of the invention that are for clarity described in the context of separate embodiments may also be provided in combination in a single embodiment. Conversely, various features of the invention that are for brevity described in the context of a single embodiment may also be provided separately or in any suitable subcombination or as suitable in any other described embodiment of the invention. Certain features described in the context of various embodiments are not to be considered essential features of those embodiments unless the embodiment is inoperable without those elements.

[0210] Various embodiments and aspects of the present invention as delineated above and as claimed in the claims section below find experimental support in the following examples.

[0211] Working Example Reference is now made to the following examples which, together with the above descriptions, illustrate the invention in a non-limiting manner.

[0212] material and method PAN ultrafiltration flat sheet membranes (model UN050) were obtained from RisingSun Membrane Technology (Beijing, China). [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl)ammonium hydroxide (SBMA; content approx. 95%), N,N'-methylenebisacrylamide (MBA; approx. 99%), zinc nitrate hexahydrate (Zn(NO3)2·6H2O, approx. 99%), sodium dodecyl sulfate (SDS, approx. 98.5%), and calcium chloride (approx. 98%) were obtained from Sigma Aldrich (Saint Louis, MO, USA). 2-Methylimidazole (2-MIM, approx. 98%) and dodecane (approx. 99+%) were obtained from Tokyo Chemical Industry (Tokyo, Japan). Potassium metabisulfite (K2S2O5, approx. 97%) and potassium persulfate (K2S2O8, approx. 99+%) were obtained from Acros. Organics (USA), ethanol (EtOH), methanol (MeOH), sodium chloride (~99.5+%), sodium hydroxide (~99%), and sodium bicarbonate (~99.7+%) were obtained from Bio-Lab Ltd. (Israel), anhydrous sodium sulfate (~99%) and magnesium chloride hexahydrate (~99%) were obtained from CARLO ERBA Reagents (France). All solutions were prepared in distilled water unless otherwise stated.

[0213] Membrane modification Prior to membrane modification, the untreated PAN membrane was washed with distilled water and then modified as follows: Untreated PAN membrane (active surface area: 0.0095 m 2 ) was hydrolyzed by treatment with 500 mL of 2 M aqueous NaOH at 65° C. for 1 h, then washed extensively with distilled water to neutral pH. The hydrolyzed membrane is referred to herein as the Hy membrane.

[0214] ZIF-8 nanoparticles were grown in situ on the active side of Hy membranes at ambient temperature as follows: Hy membranes were incubated in aqueous Zn(NO3)2·6H2O (1.25 g in 50 mL) for 12 h with shaking. The aqueous Zn(NO3)2·6H2O solution was discarded, and the membranes were washed with distilled water for 15 s, treated with aqueous 2-MIM (2.75 g in 50 mL) for 1 h with shaking, and then gently washed three times with 50% aqueous MeOH. Hy membranes containing in situ grown ZIF-8 nanoparticles are referred to as HyZif membranes.

[0215] 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 m 2 ) was first treated with 1.0 M SBMA aqueous solution (40 mL) containing 5 wt.% MBA (as a cross-linking agent) for 7.5 min with shaking, then 0.1 M K2S2O5 aqueous solution and 0.1 M K2S2O8 aqueous solution (5 mL each) were added in sequence, and shaking was continued for 30 min. The reaction was terminated by discarding the reaction mixture and washing the membrane thoroughly with distilled water. The Hy membrane and HyZif-grafted membrane are referred to as HyG membrane and HyZifG membrane, respectively.

[0216] FTIR spectra of the membrane surfaces were obtained using an ATR-FTIR spectrometer (VERTEX 70, Bruker Optiks GmbH, Ettlingen, Germany). XPS analysis was performed using an X-ray photoelectron spectrometer (ESCALAB 250, Thermo Fisher Scientific, USA) equipped with an Al Kα X-ray source and a monochromator under ultra-high vacuum conditions to determine the surface chemical composition of the membranes. XRD analysis included Cu Kα radiation (k = 1.54 Å) at a scan rate of 3° / min and in the 2θ range of 10°-38° (D / Max Ultima II, Rigaku Corporation, Japan). The membrane surfaces were observed by SEM using a JSM-IT200 instrument (JEOL, Japan). EDX elemental mapping of the surface and cross-sectional views of the HyZifG membranes was also performed. The hydrophilicity of the membranes was studied by measuring the water droplet contact angle with an OCA-20 Contact Angle System (DataPhysics Instruments, Filderstadt, Germany) using a 2 μL droplet of distilled water. The zeta potential of the membranes was measured at different pH values ​​in an asymmetric clamp cell using a SurPASS electrokinetic analyzer (Anton Paar, Graz, Austria). The surface roughness of the membranes was examined by AFM by scanning a 5 × 5 μm membrane area in QI™ mode with a NanoWizard 4 microscope (JPK Instruments, Bruker Nano GmbH, Berlin, Germany). At least three areas of each membrane were scanned to obtain the root mean square roughness (R ) as the mean ± SD. RMS ) value was obtained.

[0217] Pure water permeability The pure water permeability of the membrane was measured at 1 bar using the dead-end filtration configuration (Figure 1). The measurements were performed after achieving constant flux for at least 30 minutes of filtration and are given by Equation (1): Pure water permeability=V / (A×Δt) (1) The pure water permeability of each membrane was calculated using the formula: where V is the volume of permeate (L), A is the effective membrane area (0.00134 m2), and Δt is the duration (h). At least three readings were taken for each membrane, and each pure water permeability value is reported as the mean ± SD.

[0218] Fouling resistance and oil removal efficiency of membranes for oilfield PW treatment The fouling resistance and oil removal efficiency of the membranes 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, major ions in concentrations typical for oilfield PW, and SDS as a surfactant (detailed composition is shown in Table 1). The solution was prepared by vigorously stirring for 12 h. The oil droplet size distribution of the prepared simulated oilfield PW was measured by dynamic light scattering (DLS; ALV / CGS-8F goniometer system, ALV-GmbH, Germany). Based on measurements performed by the inventors, the simulated oilfield PW had an oil droplet size distribution in the range of 42 nm to 226 nm (data not shown). It is noted that the simulated oilfield PW also had an oil droplet size distribution in the range of 42.5 nm to 220 nm after 2 days of stirring, which was similar to the oil droplet size distribution at the beginning of the filtration experiment. It can therefore be inferred that the feed solution remained stable during the filtration experiment.

[0219] [Table 1]

[0220] The fouling resistance of the PAN, Hy, HyG, and HyZifG membranes was evaluated by a dead-end filtration experiment using a simulated oil field PW (see Figure 1). First, distilled water was passed through each membrane for 1 hour and then filtered. W0 The stable initial water flux (approximately 100 L m -2 h -1) was achieved. Three filtration cycles were then performed (foulant filtration, membrane cleaning, and water flux measurement). Each cycle included the following steps: Step 1 - Simulated oilfield PW was filtered for 3 h and the flux was recorded every minute. At regular time intervals, the collected permeate was returned to the stirred filtration cell to keep the feed solution concentration constant throughout the steps. Step 2 - The oilfield PW was discarded and the membrane was rehydrated with 80 L distilled water / m 2 The membrane was cleaned by agitation for 15 min (note that the distilled water washing step was not included in the filtration cycle time). Step 3 - The water flux of the cleaned membrane was measured for 1 h, which was 1 J for cycle numbers 1, 2, and 3, respectively. W1 , J W2 , and J. W3 (L m -2 h -1 The water flux was calculated using equation (1). To account for the membrane fouling resistance, the FRR was calculated using equation (2):

number

[0221] The oil removal efficiency (R exp ) into equation (3)

number

[0222] The stability of the methacrylate hydrogel-grafted ZIF-8 layer on the HyZifG membrane was examined by comparing FTIR spectra and EDX elemental analysis before and after the fouling experiment. Furthermore, the leaching of ZIF-8 nanoparticles from the HyZifG membrane was detected by collecting the retentate (15 min after the start of the fouling filtration experiment) and permeate (at fixed time intervals) and analyzing them using an inductively coupled plasma optical emission spectrometer (ICP-OES, SPECTRO ARCOS, AMETEK, Inc., USA). The detection and quantification limits of ICP-OES for zinc are 1 ppb and 10 ppb, respectively.

[0223] The HyZifG membrane was selected to carry out long-term anti-fouling experiments. Ten filtration cycles were carried out using simulated oil field produced water as the foulant solution. The filtration protocol was the same as that described above.

[0224] Example 1 Preparation of ZIF-8 modified membranes and stabilization of ZIF-8 layers A hydrophilic support membrane should provide high flux, excellent oil rejection, and lower fouling than hydrophobic membranes. Therefore, PAN membrane was selected as the porous support due to its higher hydrophilicity than PVDF support. Furthermore, the continuous ZIF-8 nanoparticle layer on the membrane surface formed by in situ growth requires the presence of surface coordination groups such as carboxyl groups. Therefore, the untreated PAN membrane was partially hydrolyzed to introduce surface carboxyl groups (Scheme 1, step 1) to provide sufficient anchoring sites to form a continuous ZIF-8 nanoparticle layer on the membrane surface (Scheme 1, step 2)

[34] . The coverage of the Hy membrane surface by the ZIF-8 nanoparticle layer can be seen by SEM analysis (Figure 14A-C). It is pertinent to note that the in situ growth of ZIF-8 nanoparticles was performed on the membrane surface under conditions compatible with porous UF membranes (room temperature in water).

[0225] Finally, a cross-linked zwitterionic hydrogel containing sulfonic acid groups was introduced to chemically stabilize the ZIF-8 layer. Redox-initiated graft polymerization introduced a methacrylate zwitterionic hydrogel on top of the ZIF-8 layer to maintain the integrity and stability of the ZIF-8 layer (Figure 2, step 3). The coating of the ZIF-8 nanoparticle layer with the redox-grafted methacrylate hydrogel can be seen in the SEM images (Figure S4E). The membranes were characterized using various techniques to elucidate their physicochemical properties and their performance in oilfield PW treatment was studied.

[0226] Figure 3 shows the FTIR spectrum of the modified membrane compared to an untreated PAN membrane. The FTIR spectrum of the untreated PAN membrane shows a band at 1451 cm, which corresponds to the C-N stretch of the -C≡N group. -1 and 2245 cm -1 In addition, it had a peak at 2939 cm -1 The peak at 1737cm corresponds to the CH stretching. -1 An additional peak at 1565 cm corresponds to the carbonyl-C=O stretch (in carboxylic acid or ester) and may be due to additives present in commercial PAN films. Hydrolysis of PAN films (Hy films) is accompanied by a peak at 1565 cm corresponding to the NH group in the carboxamide and the carbonyl group (C=O). -1 and 1668 cm -1 [39, 40], as well as the prominent peak at 1405 cm, which indicates the carboxyl groups on the Hy membrane surface. -1

[40] Furthermore, a new peak was observed in the range of 3200–3500 cm -1 The peaks appearing at 671 cm correspond to the OH moieties of the carboxyl groups on the film surface. The appearance of these peaks confirmed the partial hydrolysis of the PAN film. In situ growth of ZIF-8 nanoparticles on the Hy film provided the HyZif film (Figure 3), which showed peaks at 683 cm, corresponding to the stretching vibration of the octahedral coordinated ZnO bond, the bending vibration of the imidazole ring, the bending vibration of the -CH group in 2-methylimidazole, and the aliphatic CH stretching of the imidazole ring, respectively. -1 , 758cm -1 , 1378cm -1, and 2870 cm -1 The appearance of these peaks confirmed the presence of ZIF-8 nanoparticles on the membrane surface. Grafting of poly(methacrylate) hydrogel onto the Hy membrane showed peaks at 1043 cm -1 (Sulfonic acid S=O stretching), 1229cm -1 (CO-NH stretching vibration of amide group), 1672cm -1 (amide C=O), 1729cm -1 (ester C=O stretching) peak and 3250-3450 cm corresponding to the stretching vibration of NH in the amide group of poly(MBA-co-SBMA). -1 The appearance of these peaks confirmed the presence of the grafted methacrylate hydrogel on the membrane surface. The FTIR spectrum of the HyZifG membrane had peaks characteristic of ZIF-8 nanoparticles (observed in the FTIR spectrum of the HyZif membrane) and peaks originating from the grafted methacrylate hydrogel (observed in the FTIR spectrum of the HyG membrane), confirming the modification of the membrane with ZIF-8 nanoparticles and grafted hydrogel. These various groups on the membrane surface affect the surface properties of the membranes and therefore their separation performance, as will be discussed later.

[0227] The surface elemental composition of the prepared films was quantified using XPS analysis (Table S1).

[0228] [Table 2]

[0229] The XPS wide spectrum of these membranes is also shown in Figure 3B. It can be inferred from the results that the O content increased upon hydrolysis of the untreated PAN membrane, indicating the presence of oxygen-rich surface groups on the high Hy membrane compared to the untreated PAN membrane. Upon grafting of poly(methacrylate) hydrogel, the HyG membrane showed a higher S content due to sulfonic acid groups in the SBMA polymer, which confirms the membrane modification with the grafted methacrylate hydrogel. The appearance of Zn in the HyZif membrane was accompanied by a decrease in oxygen content and an increase in nitrogen content, confirming the in situ grown ZIF-8 nanoparticles on the membrane surface. Grafting on the HyZif membrane with methacrylate hydrogel (HyZifG membrane) masked the ZIF-8 layer, which led to a decrease in Zn content, the appearance of sulfur, and an increase in oxygen in the HyZifG membrane. Thus, the XPS surface analysis confirms the successful modification of the membrane.

[0230] Figure 4 shows the XRD spectra of the prepared films. The spectrum of the PAN film had three peaks, a peak at 2θ=18° characteristic of the hexagonal crystals of PAN, and two other peaks at 2θ=22.8° and 26.1°, possibly due to the crystalline phase of the PAN film. These peaks were also observed in the Hy and HyG films, although with slight variations in intensity. The intensity of the peak at 2θ=22.8° was substantially reduced in the HyZif and HyZifG films compared to the untreated film, due to the presence of a coating layer of ZIF-8 nanoparticles that masked the underlying PAN support. The HyZif film provided several diffraction peaks at 2θ=7.5°, 10.5°, and 12.8°, which correspond to the (011), (002), and (112) reflections, respectively (the XRD spectrum of the untreated ZIF-8 nanoparticles is shown in Figure 4B). In addition, two diffraction peaks appeared at 2θ = 17.8° and 26.1°, corresponding to the (222) and (134) reflections, respectively, which matched the peaks recorded in the spectrum of untreated PAN. These peaks were also recorded in the HyZifG film, confirming the overall modification of the PAN film with the methacrylate hydrogel-grafted ZIF-8 layer.

[0231] EDX elemental mapping of the cross-section and surface of the HyZifG membrane was performed to investigate the distribution of ZIF-8 nanoparticles on the membrane. Figure 5A-B shows the microscopic maps of C, N, O, and Zn on the HyZifG membrane. The element Zn is a unique component of ZIF-8 nanoparticles, confirming the presence of a ZIF-8 layer stabilized by a methacrylate hydrogel layer on the membrane surface.

[0232] The surface charge of the membrane is important for separation applications, and the zeta potential of the PAN, Hy, and HyG membranes was measured using the streaming potential method (Figure 13). All membranes had a net negative surface charge at pH values ​​above 4.0, with the untreated PAN and Hy membranes exhibiting the most negative values. However, the Hy membrane showed a steep titration gradient in the pH range of 3.0-5.5 (the isoelectric point is at pH 4.0), which is typical for carboxyl titration and clearly indicates a high concentration of carboxyl groups on the Hy membrane surface. Redox-initiated graft polymerization on the Hy membrane provided the HyG membrane, which showed an overall reduction in negative surface charge (smaller negative zeta potential) compared to the untreated membrane, probably due to the zwitterionic-neutral nature of the SBMA monomer used in the polymerization reaction and partial masking of the membrane surface. The zeta potential measurements confirm the successful hydrolysis of the untreated PAN membrane and its subsequent modification with methacrylate hydrogel. Furthermore, at pH 6.5, which was the working pH for the anti-fouling experiments, the zeta potential value of the HyZifG membrane was −14.5 ± −0.6 mV, indicating that all studied membranes had negative zeta potential values ​​at the working pH.

[0233] Surface roughness is an important property of membranes used in separation applications and can affect the tendency of membrane fouling. AFM was used to measure the roughness of RMS The surface roughness of the film was measured from the surface roughness points of the film (Fig. 7). The untreated PAN film had an R of 26.2 ± 1.8 nm. RMSvalues, which decreased to 21.3 ± 1.4 nm for the Hy membrane, indicating that hydrolysis smoothed the membrane surface. The roughness was further reduced to 16.9 ± 1.0 nm for the HyG membrane by methacrylate hydrogel layer coating via redox-initiated graft polymerization. AFM analysis was performed in water, where the hydrogel layer is expected to swell and thus provide a smooth surface. 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 non-uniform surface formed by the ZIF-8 nanoparticles. Redox grafting with 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 compared to the Hy membrane. The interplay between the wettability and roughness of the membrane will affect its separation performance for treating oilfield PW, as will be discussed later, and its anti-fouling behavior.

[0234] Example 2 Membrane performance The performance of the exemplary membranes of the present invention (prepared according to the above process) in oilfield PW treatment was studied in terms of pure water permeability, anti-fouling property, and oil removal efficiency.

[0235] Pure water permeability High pure water permeability is desirable for separation applications. Figure 8 shows the pure water permeability of the prepared membranes. The pure water permeability of the PAN membrane was 396.1 ± 6.5 L·m-2·h-1·bar-1, which increased to 546.5 ± 8.3 L·m-2·h-1·bar-1 (138% increase) and 676.2 ± 8.7 L·m-2·h-1·bar-1 (171% increase) for the Hy and HyG membranes, respectively. These increases in pure water permeability can be attributed to the hydrophilicity of the membranes, evident from their water contact angle values, due to the presence of hydrophilic 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-2·h-1·bar-1, about 13% higher than that of the untreated PAN membrane, consistent with its high hydrophilicity and desirable for separation applications. The pure water permeability of HyZifG was lower than that of the Hy and HyG membranes due to its relatively low hydrophilicity (high water contact angle).

[0236] Fouling resistance for oilfield PW filtration The composition and properties of PW from the oil and gas industry vary depending on the geographic location of the field and the drilling technique used. The inventors collected information from various fields and test solutions were designed with chemical compositions typical of oilfield PW in terms of major ions, pH, and salinity, using dodecane as the hydrocarbon component (see Table 1 for detailed composition and properties). Anti-fouling experiments were conducted by filtering simulated oilfield PW through PAN, Hy, HyG, and HyZifG membranes to elucidate the specific anti-fouling contributions of PAN hydrolysis, redox-initiated graft polymerization, and the overall performance of the ZIF-8 layer on the membrane.

[0237] Figure 9 shows the filtration of simulated oilfield PW through different membranes to determine the anti-fouling behavior of those membranes. The stable initial permeate flux (100 L m -2 h -1) were obtained for all membranes by adjusting the pressure. As the fouling experiment progressed, the flux of each membrane changed depending on its anti-fouling properties. Three filtration cycles are shown in Figure 9. The anti-fouling behavior of the membranes is presented in terms of FRR in Table 2. It is evident from the data that the untreated PAN membrane was prone to fouling as the FRR decreased significantly with each fouling cycle (FRR = 49.9 ± 0.9%, 29.4 ± 0.6%, and 8.1 ± 0.7% for the first, second, and third fouling cycles, respectively). The Hy and HyG membranes (modified by hydrolysis and graft polymerization, respectively) provided stepwise improved FRR values ​​compared to the untreated PAN membrane, indicating that every modification step aided the anti-fouling behavior. The FRR values ​​of the Hy membranes (69.9 ± 1.4%, 55.2 ± 1.5%, and 40.1 ± 1.7%, for the first, second, and third fouling cycles, respectively) were higher than those calculated for the untreated PAN membrane, while the FRR values ​​of the HyG membranes were 82.5 ± 1.3%, 73.8 ± 1.6%, and 61.7 ± 1.5%, respectively. Thus, the observed trend was FRR(HyG) > FRR(Hy) > FRR(PAN), reflecting the hydrophilicity and surface roughness of the Hy and HyG membranes. A hydrophilic membrane with a smooth surface facilitates the formation of a hydration layer on the membrane surface, which resists the deposition of foulants, and thus exhibits high anti-fouling properties. The inventors found that the hydrophilicity of the membranes (evident from the water contact angle values, Figure 6) and the smoothness of the surface (surface roughness of the membrane, R RMS It was observed that the flux density (Fr) values ​​(Figure 7) of the HyZifG membranes followed the trend HyG>Hy>PAN, consistent with their anti-fouling performance. Significantly, the HyZifG membrane exhibited outstanding anti-fouling performance for filtration of oilfield PW (foulants) with excellent anti-fouling ability indicated by FRR values ​​of 99.5±0.5%, 99.1±0.7%, and 98.5±0.6% for the first, second, and third fouling cycles, respectively. The HyZifG membrane showed an exceptional ability to recover its original flux with only minor loss immediately after cleaning of the membrane surface by washing (15 min agitation in distilled water).

[0238] The good anti-fouling behavior of the HyZifG membrane can be attributed to the presence of the methacrylate hydrogel-grafted ZIF-8 layer on the membrane surface, which is hydrophilic and provides strong resistance to the adhesion of oily foulants to the membrane surface. Furthermore, the low MWCO value (Table S2) due to the presence of the methacrylate hydrogel-grafted ZIF-8 layer on the HyZifG membrane can prevent the clogging of pores by oily foulants and allow water to permeate the membrane preferentially, resulting in a high water flux of the membrane (Figure 10). Therefore, the HyZifG membrane showed the best anti-fouling performance.

[0239] [Table 3]

[0240] The observed trends in the anti-fouling performance of the membranes for the filtration of oilfield PW were further supported by SEM studies of their surfaces before and after filtration (Figure 11). The SEM images show that the surface of the untreated PAN membrane had the highest amount of foulant deposition. In contrast, the HyZifG membrane showed negligible foulant deposition, supporting its superior anti-fouling properties for oilfield PW. The HyZifG membrane remained stable even after three 4-h filtration cycles, as determined by comparing the FTIR spectra of the membrane before and after the fouling experiment (Figure 12). The FTIR spectrum of the HyZifG membrane after filtration showed all the major characteristic peaks of ZIF-8 nanoparticles observed using the virgin membrane (before the start of the fouling experiment), confirming that the ZIF-8 layer on the membrane surface remained unchanged even after performing all the filtration experiments. Moreover, the EDX elemental composition of the virgin and used HyZifG membranes remained almost the same (Table S3), indicating the stability of the ZIF-8 layer beneath the methacrylate hydrogel on the HyZifG membrane. Furthermore, the leaching of ZIF-8 nanoparticles from the HyZifG membrane during the fouling experiments was confirmed by the ZnO / ... 2+ The concentration of Zn in the retentate and permeate was examined by ICP-OES. 2+was not detected below the detectable limit of ICP (1 ppb), implying the hydrostability of the ZIF-8 layer in the HyZifG membrane below the ICP analytical threshold during anti-fouling filtration experiments.

[0241] The oil removal efficiency (R exp ) were found to follow the same trend as their anti-fouling performance. The HyZifG membrane had the highest value (99.7 ± 0.3%), followed by the HyG membrane (97.5 ± 0.6%), Hy membrane (96.9 ± 0.7%), and untreated PAN membrane (96.5 ± 0.5%). The trend of the rejection values ​​of the different membranes is consistent with their MWCO values ​​(Table S2). The untreated PAN membrane had the highest MWCO value (325.4 kDa) and showed an oil rejection value of 96.5 ± 0.5%. Meanwhile, the HyZifG membrane had the lowest MWCO value (265.2 kDa), which showed the highest oil rejection value (99.7 ± 0.3%), followed by the HyG membrane (97.5 ± 0.6%) and Hy membrane (96.9 ± 0.7%), which had MWCO values ​​of 305.6 and 310.7 kDa, respectively. Clearly, size exclusion is the dominant separation mechanism by the four membranes tested. The superior oil rejection efficiency of the HyZifG membrane can be attributed to the presence of a ZIF-8 layer, which leads to a lower MWCO value and thus prevents oil from passing through the membrane [10, 51, 52]. The rejection percentages of ions in simulated PW solutions by the membranes were measured using ICP analysis of the feed and permeate and are shown in Table S4. The obtained rejection values ​​ranged from 1% to 16%, with the highest rejection values ​​measured for the HyZifG membrane. The low rejection values ​​of inorganic ions are as expected for UF membranes.

[0242] The anti-fouling performance of the HyZifG membrane was tested for 42 hours (10 filtration cycles) and is shown in Figure 13. After 10 filtration cycles, the HyZifG membrane exhibited an FRR value of 90.3%, where the gradual decrease in the FRR value after each filtration cycle can be attributed to the clogging of pores by foulants over time. Notably, the oil removal efficiency remained >99% throughout the entire filtration duration. These results clearly indicate that the HyZifG membrane exhibits promising suitability for the treatment of oilfield produced water.

[0243] The performance of the HyZifG membrane in treating oilfield PW is comparable to that of previously reported membranes for oily wastewater treatment. The performance of the exemplary membrane of the present invention is demonstrated in Table 3. As shown in Table 3, the exemplary HyZifG membrane of the present invention exhibited excellent anti-fouling ability (FRR about 90.3%) and oil removal efficiency (>99%) for oilfield PW treatment.

[0244] [Table 4]

[0245] Overall, the results show, discuss and demonstrate here the successful design and preparation of HyZifG membranes, as well as that the membranes have excellent anti-fouling properties, high water flux, high oil removal efficiency, and stability during filtration. The described polyacrylonitrile membranes with methacrylate hydrogel-grafted ZIF-8 layers, prepared using a facile method, are therefore promising for the separation and treatment of oilfield PW.

[0246] Molecular Weight Cut-Off (MWCO) Analysis The MWCO of the membrane was determined by polyethylene glycol (M n = 35 kDa; Sigma Aldrich, MO, USA) and polyethylene oxide (M n = 100, 200, 400, and 600 kDa; Sigma Aldrich, MO, USA) were used as molecular markers. The concentration of each molecular marker at 1 g L -1 Solutions were prepared separately in Milli-Q water and filtered separately through the membrane at room temperature using an Amicon® stirred dead-end filtration cell (300 rpm) at 1 bar. The concentrations of the molecular markers were determined using a TOC analyzer (Multi N / C, 2100S, Analytikjena, Germany) to measure the concentration of the feed solution (C f ) and permeation solution (C p The total organic carbon (TOC) concentration of the markers was measured in the feed and permeate by measuring the TOC concentration of the markers. The rejection of the markers was calculated using the following equation (S1) and plotted against their molecular weight:

number

[0247] For each membrane, the MWCO value, defined as the molecular weight at 90% rejection, was calculated from the rejection vs. molecular weight graph. The MWCO values ​​of different membranes are shown in Table S2.

[0248] [Table 5]

[0249] [Table 6]

[0250] [Table 7]

[0251] Example 3 Stabilized COF-300 nanoparticles on polymer membranes for efficient removal of PFAS contaminants from contaminated water 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 the solution was cooled 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 maintained at 120 °C for 72 h. The reaction mixture was allowed to cool to room temperature. The resulting yellow solid was then washed as per the following protocol: (1) centrifugation three times using 1,4-dioxane, (2) shaking in 1,4-dioxane for 24 h, (3) centrifugation and discarding 1,4-dioxane, (4) centrifugation three times using isopropanol, (5) shaking in isopropanol for 24 h, (6) centrifugation and discarding isopropanol. Finally, it was dried in vacuum at 60°C for 24 hours.

[0252] The prepared nanoparticles were characterized for their morphology by scanning electron microscopy (SEM), for their chemical functionality by Fourier transform infrared spectroscopy (FTIR), and for their crystallinity by X-ray diffraction (XRD) spectroscopy. The SEM images (Figure 15(A-B)) show the oblong shape of the COF nanoparticles. The FTIR spectrum of the prepared nanoparticles is shown in Figure 1-C and shows a peak at 1625 cm -1 (attributed to the imine C=N stretching), and 2926 cm -1 (attributed to the imine-derived alkene C-H stretching) characteristic peaks of COF-300 nanoparticles, confirming their structure [Uribe-Romo et al. Journal of the American Chemical Society 131 (2009) 4570-4571]. Other important peaks are also seen at 947 cm -1 (Aromatic CH out-of-plane vibration from TAPM), 1007 cm -1 (Aromatic CH in-plane bending from TAPM), 1480cm -1 (aromatic C-C ring stretch from phenyl ring), 1512 cm -1 (aromatic ring stretching from the phenyl ring in TAPM), and 1836 cm -1 (aromatic CH bending overtones).

[0253] Figure 15D shows the XRD pattern of COF-300 nanoparticles. Characteristic peaks appeared 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. PAN UF membrane was hydrolyzed as described above (Example 1 and Materials and Methods).

[0254] The COF-300 nanoparticles were then deposited on the hydrolyzed PAN membrane by vacuum filtration. The amount of COF-300 nanoparticles was 20 μg cm -2 Figure 16 shows the SEM image of COF-300 nanoparticles deposited on the membrane surface. Redox-initiated graft polymerization was then carried out on the membrane surface as described above (Example 1 and Materials and Methods). Successful membrane modification was confirmed by FTIR analysis, which showed characteristic peaks of methacrylate hydrogel and characteristic peaks of COF-300 nanoparticles.

[0255] The separation performance of the modified membrane was measured. The pure water permeability was 68.6 L m -2 h -1 Bar -1 Furthermore, the PFOA removal efficiency was determined by filtering real groundwater samples spiked with PFOA. The groundwater samples were collected from a well near Kibbutz Yad Mordechai (well Yad Mordechai-1) and their composition can be seen in Table 4. The groundwater was spiked with PFOA at a concentration of 500 ppb. The modified membrane removed 67.6% of PFOA and 74.3% of nitric acid from the spiked real groundwater sample with a permeate flux of 52.9 L m (at 2 bar). -2 h -1 It was.

[0256] [Table 8]

[0257] Cross-linking degree evaluation The inventors have produced the coated membranes disclosed herein using 2.5 and 5 wt. % MBA crosslinker in addition to hydrophilic monomers during graft polymerization as a means to stabilize functional nanoparticles on the membrane surface without interfering with its separation performance.

[0258] The fouling resistance of the modified membrane was examined by measuring the flux after filtration of PFAS-contaminated water and subsequent washing with water, and the flux recovery was 96%, indicating the excellent fouling resistance tendency of the modified membrane. The membrane stability was also examined by recording the FTIR spectrum of the used modified membrane and comparing it with the spectrum before filtration, and the comparison suggested that the spectrum remained the same, indicating that the modified (COF-300 / methacrylate hydrogel) layer remained unchanged after performing the large-scale filtration experiment. These results demonstrated the effectiveness of the membrane of the present invention modified by a methacrylate hydrogel-stabilized COF-300 nanoparticle layer for the efficient removal of PFOA from contaminated groundwater.

[0259] Further examples of COF-300 nanoparticles deposited on PAN membranes (PAN RS50 membranes) were prepared with different surface densities on the membrane: 187, 93, and 23 μg / cm. 2 The inventors have succeeded in producing PAN membranes with nanoparticles of COF nanoparticles of about 0.5 μm in length. Furthermore, different surface densities resulted in similar top views of the top layer of nanoparticles.

[0260] Results of nanoparticle stabilization without the use of crosslinkers To further justify the importance of using MBAA crosslinker in grafting, initial experiments were performed to stabilize a layer of ZIF-8 nanoparticles on the membrane surface without using a crosslinker in the redox-initiated graft polymerization. The stability of the nanoparticle layer on the modified membrane was examined by performing EDS elemental analysis on unused and used (after filtration experiments) membrane samples. It was found that the composition of zinc (a component of ZIF-8 nanoparticles) decreased from 4-5 wt.% to less than 0.1 wt.%, indicating that the hydrogel (without crosslinker) was not suitable for stabilizing the nanoparticle layer on the membrane surface. It is noteworthy that the composition of zinc in the membrane modified with crosslinked hydrogel remained the same (4-5 wt.%) after extensive filtration experiments. Based on the above, the importance of using crosslinked polymers in the coating of the present invention should be understood. It is assumed that the optimal crosslinking degree of the polymers disclosed herein is 1-20%. Alternatively, the w / w ratio and / or molar ratio of the polymer to the crosslinker is 1-20% as disclosed herein.

[0261] Furthermore, the inventors have successfully prepared various CFSs on polymer membranes stabilized by graft copolymers as disclosed herein.

[0262] For example, ZIF-8 nanoparticles grown in-situ on a PAN membrane with a molecular weight cut-off value of 325.4 kDa, ZIF-67 nanoparticles grown in-situ on a PAN membrane with a molecular weight cut-off value of 105 kDa, Co / Zn-based ZIF-L nanoparticles (particle size 1 to about 10 μm) grown in-situ on a PAN membrane with a molecular weight cut-off value of 105 kDa, Zn-based ZIF-L particles (particle size 1 to about 5 μm) grown in-situ on a polyethersulfone (PES) membrane with a molecular weight cut-off value of 75 kDa, and ZIF-8 nanoparticles grown in-situ on a PES membrane with a molecular weight cut-off value of 50 kDa were successfully prepared and stabilized by graft copolymers as disclosed herein.

[0263] Example 4 Ultrafiltration Water Treatment Membrane material Nanofiltration (NF90 and NF200) and polyacrylonitrile (PAN) ultrafiltration flat sheet membranes were provided by DuPont FilmTec Co. (Midland, MI, USA) and RisingSun Membrane Technology (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 2,2,3,4,4,4-hexafluorobutyl methacrylate fluorinated monomer 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 the study were not further purified.

[0264] Hexane, absolute ethanol, absolute methanol, and isopropanol (IPA) were purchased from Bio-Lab Ltd. (Jerusalem, Israel). Photoinitiator benzophenone (BP, 99%), and bovine serum albumin (98%) foulant were obtained from Sigma-Aldrich Chemical Co. (St. Louis, MO, USA). Potassium hydroxide flakes were purchased from Bio-Lab Ltd. (Jerusalem, Israel).

[0265] Barium chloride dihydrate (99%), potassium nitrate (99%), calcium chloride dihydrate (99%), iron(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 stated.

[0266] Modification of PAN UF composite membrane with hydrogel-stabilized MOF Hydrolysis of PAN membrane. Surface area 0.00541 m 2 The untreated PAN membrane was washed with water overnight and then hydrolyzed with 1M KOH aqueous solution at 60° C. for 1 h at 300 rpm. 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 Hy membrane.

[0267] In-situ formation of ZIF-67 nanoparticle layer on Hy membrane. Aqueous Co(NO3)2·6H2O solution (0.44 g in 30 mL) was prepared and incubated with Hy membrane for 12 h at 25 °C under continuous shaking at 85 rpm. The aqueous Co(NO3)2·6H2O solution was then discarded and the membrane was washed with DI water for 1 min under shaking. The membrane was then incubated with aqueous 2-methylimidazole (2-MIM) organic linker solution (0.974 g in 30 mL) for 9 h under continuous shaking at 85 rpm. The 2-MIM solution was discarded and the membrane was washed three times with running DI water. The Hy membrane with in-situ grown ZIF-67 nanoparticles was named HyZIF67.

[0268] Graft polymerization using zwitterionic methacrylate monomers. Hy and HyZIF67 membranes were surface modified by graft polymerization using UV irradiation for 5, 7.5, and 10 min. The membranes were first incubated with BP photoinitiator (0.05M and 0.1M in 30 mL of 80% ethanol / water solution) for 10 and 30 min. The BP solution was then discarded and the membrane surface was washed with water with shaking at 85 rpm for 1 min to remove residual BP. Afterwards, the membranes were incubated with 0.8 M SBMA solution containing 0.04 M MBA crosslinker in 30 mL of aqueous solution with shaking. The incubation time of the SBMA / MBA solution on the membrane surface was 30 s at 25° C. before UV grafting. The process was kept in dark conditions to avoid UV activation before irradiation. The membranes were then UV irradiated for 5, 7.5, and 10 min at 50% UV light intensity. The grafted membranes were taken out and immediately rinsed with DI water to remove unreacted and ungrafted SBMA monomers and chains from the membrane surface. The SBMA-co-MBA grafted Hy and HyZIF67 membranes were named HyG and HyZIF67G membranes, respectively, and stored in DI water overnight for further evaluation and analysis.

[0269] Inductively Coupled Plasma Optical Emission Spectroscopy Analysis. An inductively coupled plasma optical emission spectrometer (ICP-OES; SPECTRO ARCOS, AMETEK, Inc., USA) was used to determine the elemental composition of the samples by measuring the emission spectrum when the solution was introduced into the plasma. The method uses argon, air, and nitrogen gases for its operation. The ICP-OES was operated to determine the concentration of Co, a constituent element of the ZIF-67 nanoparticles, in the feed and permeate solutions 15 minutes after the start of the filtration experiment. At least two measurements from the feed and permeate of the HyZIF67G membrane were taken for analysis, and the average values ​​were presented in this study.

[0270] Atomic Force Microscopy. The surface roughness of the films was measured by atomic force microscopy (AFM) in QI™ mode using a NanoWizard 4 microscope (JPK Instruments, Bruker Nano GmbH, Berlin, Germany). The AFM was operated in tapping mode in both air and humid atmosphere. The root mean square (RMS) roughness values ​​in a 5 μm×5 μm area of ​​the film surface were calculated for at least three different areas of each film. The RMS roughness values ​​were reported as the mean ± standard deviation (SD).

[0271] Bradford protein assay. The Bradford protein assay was performed by using Quick Start Bradford dye reagent concentrate for protein quantification (Bio-Rad Laboratories GmbH, Feldkirchen, Germany). 100 mg L -1 of BSA solution was filtered through the modified membrane for 1 h. 10 mL of aqueous BSA solution from the feed and permeate were collected after filtration. The absorbance of BSA present in at least 5 samples of the feed and permeate was measured at 595 nm using a UV-Vis spectrophotometer (Infinite M200 plate reader, Tecan, Australia). Each sample preparation followed the low BSA profile concentration protocol, where 800 μL of sample was first vortexed with 200 μL of Bradford reagent for a few seconds, and after 5 min, the sample was placed in a costar 48 flat transparent plate for absorbance measurement. A calibration curve of BSA absorbance was performed at 1, 5, 10, and 15 mg L -1 The results are plotted against the BSA concentration.

[0272] Pure water permeability measurement. The pure water permeability (PWP) of NF membrane and PAN membrane was measured at 0.00134m 2 A stainless steel dead-end filtration cell configuration containing a single membrane with an effective area of ​​1000 nM (diameter 4.13 cm) was used for the evaluation. A schematic diagram of the experimental filtration configuration is shown in Figure 1.

[0273] Evaluation of the PWP of PAN membranes. The same dead-end filtration configuration was used for the PAN membranes. PWP measurements were taken after obtaining a steady water flux after a compression time of 1-2 hours at 2 bar. Water permeabilities were collected at regular intervals of 15 minutes over a period of 1 hour and the measured values ​​were recorded for each membrane. The PWP of the membranes was calculated using equation (3.1).

[0274] The BSA foulant was selected as a model foulant to examine the membrane performance in this study. The fouling resistance of the membranes was evaluated using the same dead-end filtration configuration described herein. Three types of fouling solutions were added at 100 mg L -1 The BSA foulants were created by dissolving 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 from the Shafdan Wastewater Treatment Plant in Israel during July–August 2015 and are shown in Table 5. First, the untreated PAN membrane and the modified membrane were compressed at 2 bar to obtain a steady-state flux for 1–2 h in one of the three background solutions. Filtration experiments were performed at approximately 100 L m -2 h -1 The experiment started by obtaining a steady state permeate flux (J0) of 0.01 ml / min, and J0 was recorded for each membrane over a period of 30 min at successive 3 min intervals with each of the background solutions.

[0275] Next, fouling experiments were carried out on the PAN, HyG, and HyZIF67G membranes separately using BSA / DI water (pH 5.85), BSA / NaCl (pH 6.55), or BSA / SSWW (pH 6.76 and pH 7.43) solutions. Each fouling solution was filtered and the flux (J t ) was recorded at 3 min intervals for 1 h. After 1 h of filtration, the fouled membrane was cleaned with DI water for 15 min with stirring and no pressure. Finally, the background solution was introduced and the flux (J) of the cleaned membrane was measured. c ) was measured at 3-minute intervals over a 30-minute period. -2 h -1The unit membrane permeate flux is calculated using equation (3.3):

number

[0276] To evaluate the fouling resistance of the PAN modified membrane, the flux recovery was calculated using Equation (3.4),

number

[0277] Preparation of synthetic secondary wastewater effluent. A synthetic solution was prepared simulating the chemistry of the secondary treatment effluent of the Shafdan Wastewater Treatment Plant in the Tel Aviv district of Israel. The composition of the SSWW can be seen in Table 3.1. After dissolving the relevant salts, the prepared solution was stirred for at least 6 hours before the introduction of BSA for the fouling experiments. [Table 9]

[0278] Hydrogel-stabilized zeolitic imidazole framework-67 nanoparticles on PAN ultrafiltration membranes Porous PAN membrane was selected to stabilize in situ grown ZIF-67 nanoparticles via UV graft polymerization of methacrylate hydrogel layer to improve the fouling resistance of the membrane. PAN membrane was hydrolyzed by KOH solution resulting in carboxyl groups on the membrane surface (named Hy membrane). Hy membrane was used as the substrate for grafting in situ ZIF-67 nanoparticles (named HyZIF67). HyZIF67 membrane surface was further modified with SBMA methacrylate monomer using UV graft polymerization technique and the resulting membrane was named HyZIF67G. Preparation of stabilized ZIF-67 nanoparticles on PAN membrane by UV grafting of zwitterionic methacrylate hydrogel monomer is shown in Figure 17. UV grafting of Hy membrane with the same monomer was performed as a reference membrane to obtain HyG membrane (Figure 17).

[0279] Four variants of membrane modification were established and compared throughout the study. Each protocol was set to optimize certain parameters, such as BP initiator concentration, UV irradiation time, and BP incubation time. In the first and second protocols, the UV irradiation time was kept at 5 and 10 min, respectively, while the BP photoinitiator concentration (0.05 M) and BP incubation time (10 min) were kept constant. In protocols 3 and 4, the BP incubation time was set at 10 and 30 min, respectively, while the BP photoinitiator concentration (0.1 M) and UV irradiation time (10 min) were kept constant. Protocols 1 to 4 are listed in Table 6.

[0280] [Table 10]

[0281] To confirm the synthesis and formation of ZIF-67 nanoparticles on the surface of PAN membranes and the UV grafting of methacrylate copolymers on the modified membranes, FTIR, EDX, XRD, WCA, SEM, and AFM analyses were performed. More specifically, the membrane surface functional groups were confirmed by FTIR, and the presence of characteristic elements and the crystallinity of the membrane surface were studied using EDX and XRD, respectively. The surface morphology and roughness of the synthesized nanoparticles and modified membranes were characterized by SEM and AFM analyses, respectively, while the water contact angle analysis gave insight into the hydrophilicity of the membranes.

[0282] The presence of organic functional groups on the surface of the untreated PAN membrane and the modified membrane was investigated by ATR-FTIR spectroscopy. -1 and 2240 cm -1 The peak is the nitrile stretching vibration of -C≡N. 71、72、73 Due to 1741cm -1 The peak at is associated with carbonyl group (C=O) stretching, which can be attributed to carboxylic acids or esters from additives used during the preparation of commercial PAN membranes.

[0283] The hydrolysis of the PAN film was carried out in an alkaline KOH solution, and the FTIR spectrum of the Hy film showed a peak at 1729 cm -1 and 1672 cm -1 This indicates the conversion of surface nitrile groups to carboxylic acid groups, which is associated with the appearance of a new peak at 1563 cm (as a shoulder). -1 which may be related to the NH group in the carboxamide (resulting from the conversion of -CN groups to -CONH2 groups by alkaline hydrolysis of the PAN film). The spectrum of the hydrolyzed PAN film provided strong evidence for the successful conversion of -CN groups to COOH and CONH2 groups during the alkaline hydrolysis process.

[0284] The FTIR spectrum of the HyG film shows a peak at 1042 cm -1 and 1181 cm -1The peak was detected, which was due to the sulfonic acid group (-SO3 - ) are assigned to the symmetric and asymmetric vibrations of 1668 cm -1 and 1727 cm -1 The appearance of the peak at 956 cm was likely associated with the C=O vibrations of amides and esters. -1 and 1148 cm -1 The peaks in Fig. 1 are characteristic peaks of the C-N stretching vibration of the quaternary ammonium group. The appearance of these peaks confirms the successful grafting of poly(SBMA-co-MBA) polymer onto the Hy membrane.

[0285] The film with in-situ grown ZIF-67 nanoparticles (HyZIF67) exhibited a 995 cm -1 , 1143cm -1 , and 1304 cm -1 More specifically, a new peak at 995 cm -1 and 1143 cm -1 The peak at 1304 cm can be assigned to the CN bending vibration. -1 The peak at can be attributed to the aromatic stretching modes of the whole imidazole ring.

[0286] Finally, the FTIR spectrum of the HyZIF67G membrane confirmed the grafting of poly(SBMA-co-MBA) on the membrane coated with ZIF-67 nanoparticles. The spectrum of HyZIF67G showed characteristic peaks of both ZIF-67 nanoparticles and methacrylate polymers compared with the FTIR spectra of the HyZIF67 and HyG membranes. To confirm the presence of ZIF-67 nanoparticles on the membrane surface, the FTIR spectra of both the PAN and HyZIF67 membranes were analyzed at 400 cm -1 ~600cm -1 The FTIR spectrum was recorded at a wavenumber of 426 cm, which is attributed to the Co-N stretching vibration of the ZIF-67 nanoparticles on the film surface. -1, which confirms that ZIF-67 nanoparticles are present on the HyZIF67 membrane.

[0287] Elemental composition by energy dispersive X-ray spectroscopy The surfaces of the films were also analyzed using EDX spectroscopy (Table 7). Compared to the untreated PAN film, the hydrolyzed films showed an increase in oxygen content, consistent with carboxyl groups obtained by hydrolysis of the nitrile groups in the PAN film.

[0288] The presence of sulfur on the surface of the HyG membrane and the increased oxygen content compared to the Hy membrane were attributed to the sulfonic acid groups of SBMA and its high oxygen content, respectively, implying successful UV grafting of methacrylate SBMA polymer on the Hy membrane.

[0289] Co 2+ appeared on the HyZIF67 membrane, accompanied by a decrease in oxygen content and an increase in nitrogen content, indicating the presence of ZIF-67 nanoparticles on the HyZIF67 membrane surface.

[0290] EDX analysis of the HyZIF67G membrane showed the presence of both sulfur and cobalt, which originated from the methacrylate SBMA grafted polymer and the ZIF-67 nanoparticles, respectively. Thus, the EDX results further support the success of the membrane modification according to FIG. 17.

[0291] [Table 11]

[0292] Film analysis by X-ray diffraction The XRD spectra of PAN, Hy, HyG, HyZIF67, and HyZIF67G are shown in Figure 4.5. The set of diffraction planes (001, 005, and 111) of the untreated PAN film has three dominant peaks at 2θ of 17.6°, 22.8°, and 25.9°, respectively, which are attributed to the crystalline structure of PAN. More specifically, the (001) plane is characteristic of the hexagonal structure of PAN, while the (005) and (111) planes are attributed to the crystallinity of the polymer chains of PAN. The characteristic peaks of ZIF-67 nanoparticles appeared at 2θ = 7.34°, 10.32°, 12.6°, 14.63°, and 16.48°, corresponding to the (011), (002), (112), (022), and (013) reflections. The appearance of these peaks indicates the successful synthesis of ZIF-67 nanoparticles and their attachment to the membrane surface, as confirmed by XRD, which shows the pattern of ZIF-67 crystals synthesized after surface modification.

[0293] Wettability of untreated and modified membranes The effect of different membrane modifications on the wettability of the membrane surface was evaluated by water contact angle measurements. Planar water drop contact angles of PAN, Hy, HyG, HyZIF67, and HyZIF67G membranes were measured as shown in Figure 18. The Hy membrane showed a decrease in water contact angle from 52.2°±0.7° for untreated PAN to 30.9°±2.6° upon hydrolysis. The increase in surface hydrophilicity can be attributed to the high concentration of carboxyl groups on the membrane surface.

[0294] The HyG membrane exhibited a water contact angle of 39.2°±1.9°, higher than that of the Hy membrane (30.9°±2.6°) but significantly lower than that of the untreated PAN. This was attributed to the presence of hydrophilic grafted hydrogel containing sulfonic acid groups of the zwitterionic SBMA polymer. This therefore indicates the successful UV grafting of the methacrylate polymer. The properties of both the Hy and HyG membranes implied an improvement in the hydrophilicity of the membrane surface.

[0295] The water contact angle of the HyZIF67 membrane was increased to 62.1° ± 2.6° by the incorporation of hydrophobic ZIF-67 nanoparticles on the membrane surface. ZIF-67 nanoparticles also increased the surface roughness, which contributed to the increase in the water contact angle. On the other hand, the HyZIF67G membrane showed a contact angle of 50.3° ± 3.3°, which is lower (and therefore more wettable) than the HyZIF67 membrane, supporting the successful coating of ZIF67 nanoparticles with the zwitterionic hydrophilic hydrogel.

[0296] Surface Morphology Figures 19A-F show SEM images of the top surface of pristine PAN, Hy, and HyG membranes. It can be seen that all surfaces exhibit smooth surface morphology. Figures 19D-E show the surface morphology of in situ grown ZIF-67 nanoparticles on two different HyZIF67 membranes, where a layer of ZIF-67 nanoparticles cohesively covers the surface. The size of the in situ grown ZIF-67 nanoparticles is about 1 μm, as confirmed by SEM analysis. The SEM image of the ZIF-67 nanoparticle layer coated by UV graft polymerization of methacrylate SBMA hydrogel (HyZIF67G membrane, Figure 19F) shows the complete coverage of the ZIF-67 nanoparticles by the methacrylate hydrogel.

[0297] Surface roughness by atomic force microscope analysis For further insight into the surface morphology, we performed AFM analysis of the roughness of the untreated and modified films. rms The values ​​were estimated based on AFM images of at least two readings from each modification, and the scan area of ​​each membrane was set to 5 × 5 μm. All AFM analyses were performed in water (wet condition), except for HyZIF67 membrane, where the analysis was performed in dry condition. The importance of surface roughness comes from its correlation with the fouling behavior of membranes, and its impact on separation performance. The surface roughness of untreated PAN and Hy membranes was measured and their R rms The values ​​were 24.5 ± 1.8 nm and 18.7 ± 0.9 nm, respectively. The Hy film showed a smooth surface compared to the PAN. The HyG film had an R of 20.2 ± 1.8 nm, which was slightly higher than the Hy film. rmsIt showed a smooth roughness having a value.

[0298] In contrast, a much higher roughness was determined for the HyZIF67 membrane compared to the Hy membrane. With the deposition of MOFs on the surface, the roughness further increased to 91.8 ± 0.9 nm. However, the HyZIF67G membrane showed a decrease in surface roughness to 51.9 ± 3.7 nm compared to HyZIF67, highlighting the influence of the presence of the methacrylate hydrogel layer. The surface roughness of the HyZIF67 and HyZIF67G membranes indicated that HyZIF67G obtained a combination of features from the grafted methacrylate layer and the ZIF-67 formation.

[0299] Separation performance of modified membranes The separation performance of the HyG membrane of the present invention and the exemplary HyZIF67G membrane were investigated by measuring their water permeability and fouling resistance using a simulated municipal wastewater solution. The pure water permeability of the HyG membrane was 311.8 ± 5.9 L m -2 h -1 Bar -1 The stabilized HyZIF67G membrane showed a slight decrease, with a PWP of 205.4 ± 3.7 L m -2 h -1 Bar -1 The PWP was shown.

[0300] Furthermore, analysis of cobalt in the permeate was performed 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 of the HyZIF67G membrane were determined by ICP analysis. Our findings were that the cobalt concentration in the feed was below the detection limit of ICP, and the Co concentration in the permeate was below the detection limit of ICP. 2+ The concentration of cobalt was very low, 82 ppb, indicating good stability of the ZIF-67 nanoparticle layer on the grafted HyZIF67G membrane surface.

[0301] Fouling resistance of modified membranes during filtration of secondary treated municipal wastewater Secondary treated municipal wastewater effluent contains high organic matter content that has serious impacts on the environment. Moreover, its treatment using membrane technology causes serious organic fouling problems. To study membrane treatment of secondary wastewater, in this study, we simulated a synthetic secondary wastewater solution containing organic foulants to mimic a real wastewater effluent. Anti-fouling experiments were performed by filtering a SSWW solution containing BSA through the membrane using a dead-end filtration cell. The composition of the simulated SSWW solution is described above. Anti-fouling experiments were performed by filtering a BSA solution in DI water, BSA in 20 mM NaCl solution (same ionic strength as SSWW), and BSA in SSWW solution.

[0302] Filtration was tested for untreated PAN and HyZIF67G membranes. First, filtration of BSA in water was tested, at 100 mg L -1 of BSA solution was introduced as the feed solution, and one filtration experiment lasted for 2 h, followed by rinsing with DI water for 15 min under stirring and no pressure. Upon contact with the BSA solution, the PAN membrane showed a severe decrease in permeate flux, while the HyZIF67G membrane experienced a relatively small decrease in permeate flux.

[0303] Further anti-fouling experiments were performed by filtering BSA in 20 mM NaCl solution through PAN and HyZIF67G membranes. Similarly, after filtration of 20 mM NaCl solution mixed with 100 ppm BSA, the PAN membrane showed a severe drop in permeate flux, while the HyZIF67G membrane showed improved anti-fouling performance and a smaller drop in permeate flux compared to the untreated PAN membrane. In conclusion, in terms of final flux and anti-fouling performance, the HyZIF67G membrane prepared by the third protocol (Table 6) showed superior performance with an FRR of 99.5% compared to the untreated membrane. Furthermore, the HyZIF67G membranes prepared according to protocols 1, 2, and 4 were compared to the HyZIF67G membrane prepared by the third protocol (Table 6), resulting in comparable performance with an FRR ranging from about 90 to about 99%.

[0304] To evaluate the BSA anti-fouling performance of the modified membranes while filtering SSWW effluent (Table 5), the permeate flux of the PAN, HyG, and HyZIF67G membranes was examined and measured during filtration of 100 ppm BSA foulant in SSWW solution at pH 6-7. Figure 20A shows that the HyG and HyZIF67G membranes showed improved anti-fouling performance when filtering BSA / SSWW solution because, compared to the untreated unmodified membrane, these membranes (I) lowered the percentage of initial flux decline and (II) increased the value of steady-state flux at the end of the fouling run. Although the HyZIF67G and HyG membranes showed similar anti-fouling performance, the HyG membrane showed 15% lower PWP compared to the HyZIF67G membrane, indicating that the HyZIF67G membrane performed best in terms of overall transport properties and anti-fouling performance. The anti-fouling performance of the PAN membrane, HyG membrane, and HyZIF67G membrane at pH 7.15 to 7.7 is shown in Figure 20B.

[0305] The BSA rejection value of the HyZIF67G membrane (third protocol) was measured using the Bradford assay. The BSA solution concentrations in the feed and permeate were 100 mg L−1, respectively. -1 and 3.334 mg L -1 Based on equation (4.1), the BSA rejection of the HyZIF67G membrane was 96.7%.

number

[0306] The surface morphologies of the membranes after the BSA / SSWW anti-fouling filtration experiments were examined using SEM, which showed different membrane surface morphologies, and the SEM micrographs (Figures 21A-B) showed some aggregates on the surfaces of the PAN, Hy, and HyG membranes. There was some foulant deposition on the surface of the untreated PAN membrane. Meanwhile, the foulant deposition was negligible for the HyZIF67G membrane, confirming its excellent anti-fouling performance.

[0307] Long-term fouling resistance of HyZIF67G membranes for secondary municipal wastewater treatment The experimental cell with dead-end filtration configuration was used for long-term anti-fouling performance experiments, and the permeate flux of the PAN and HyZIF67G membranes was tested in long-term BSA filtration experiments in SSWW solution (Table 5). A total of 10 cycles of fouling experiments were performed, with the duration of each cycle filtration being 2 h. Before starting the filtration cycle, the permeate flux was measured at 100 L m using SSWW as the feed solution. -2 h -1 and filtered for an additional 0.5 hours while measuring the flux. Each cycle then began with the filtration of a SSWW solution containing 100 ppm BSA while recording the flux transmittance every 3 minutes for 1 hour. The BSA / SSWW solution was then discarded and the fouled membrane underwent a 15 minute long wash using DI water with agitation but no pressure. The SSWW solution was then filtered for 15 minutes and for an additional 0.5 hours while measuring the flux (FIG. 22).

[0308] Based on Figure 22, the untreated PAN membrane showed severe flux degradation after 10 cycles of filtration of the SSWW foulant solution containing BSA, and the measurements showed that the flux recovery of PAN was 57.4% compared to 73.2% for the HyZIF67G membrane, which further demonstrated the effect of surface functionalization of grafted SBMA incorporating ZIF-67 nanoparticles on the fouling tendency of the membrane.

[0309] After 10 filtration cycles of synthetic secondary wastewater effluent spiked with bovine serum albumin, the HyZIF67G membrane exhibited improved anti-fouling properties with a flux recovery value of 73.2%, compared to 57.4% recovery for the untreated membrane.

[0310] It was observed that after each filtration cycle, hydraulic washing removed reversible fouling, while irreversible fouling accumulated on the membrane surface, resulting in a decrease in membrane performance. After 10 cycles of filtration experiments, the untreated membrane (54 L m -2 h -1 ) compared to the steady-state flux of the HyZIF67G membrane with a higher permeability value (73 L m -2 h -1 ) further suggested that the affinity between the BSA foulant and the HyZIF67G membrane surface was the lowest, which may provide desirable anti-fouling performance.

[0311] Compared to commercial membranes, the HyZIF67G membrane of the present invention generally exhibits better PWP (47.6 L m ) at 2 bar using SSWW solution. -2 h -1 Bar -1 ) and high flux recovery (89%), indicating that the addition of ZIF-67 nanoparticles to the HyG membrane exhibits outstanding anti-fouling performance during wastewater treatment.

[0312] Thus, an exemplary membrane of the present invention (HyZIF67G) was characterized by FTIR, EDX, and XRD to confirm the presence of ZIF-67 nanoparticles and zwitterionic methacrylate hydrogel on the membrane surface. The HyZIF67G membrane exhibited high hydrophilicity compared to untreated PAN membranes.

[0313] After 10 filtration cycles of synthetic secondary wastewater effluent spiked with bovine serum albumin, the HyZIF67G membrane exhibited improved anti-fouling properties. The flux recovery value after 10 filtration cycles was 73.2%, much higher than the 57.4% of the untreated membrane. Furthermore, the BSA rejection of the HyZIF67G membrane was about 97%. SEM images of the fouled membrane showed that the HyZIF67G membrane experienced negligible foulant deposition on its surface after filtration compared to the modified membrane without ZIF-67 nanoparticles or the PAN membrane, which explains the superior anti-fouling properties of the HyZIF67G membrane.

[0314] Therefore, the membranes disclosed herein can potentially be used for efficient UF filtration in water treatment applications such as treatment of reclaimed secondary municipal wastewater effluent, oil / water separation, whey protein concentration, and pigment / salt separation.

[0315] While the present invention has been described in conjunction with specific embodiments thereof, it is evident that many alternatives, modifications, and variations will be apparent to those skilled in the art. Accordingly, it is intended to embrace all such alternatives, modifications, and variations that fall within the spirit and broad scope of the appended claims.

[0316] All publications, patents, and patent applications mentioned herein are incorporated herein by reference in their entirety to the same extent as if each individual publication, patent, or patent application was specifically and individually indicated to be incorporated herein by reference. Furthermore, citation or identification of any reference in this application shall not be construed as an admission that such reference is available as prior art to the present invention. To the extent section headings are used, they should not be construed as necessarily limiting.

Claims

1. A membrane comprising a polymer film in contact with a coating layer comprising a plurality of crystalline framework structures (CFS) and a hydrogel comprising a crosslinked hydrophilic polymer, wherein the membrane is water permeable.

2. The membrane according to claim 1, wherein the crosslinked hydrophilic polymer comprises a polymer selected from polyacrylate or polymethacrylate.

3. The membrane according to claim 1 or 2, wherein the CFS comprises nanoparticles.

4. The membrane according to claim 3, wherein the nanoparticles are selected from covalent organic framework (COF) nanoparticles and metal-organic framework (MOF) nanoparticles.

5. The membrane according to claim 1, wherein the outer surface of the polymer film is chemically modified.

6. The membrane according to claim 5, wherein the chemical modification is by a plurality of surface groups selected from amino and carboxy.

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

8. The membrane according to claim 1, wherein the crosslinked hydrophilic polymer is characterized by a crosslinking degree of about 5%.

9. The membrane according to claim 1, characterized by any one of (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°, and (iv) a water contact angle smaller than that of the untreated polymer film.

10. The membrane according to claim 9, characterized by a water contact angle about 13% smaller than that of the untreated polymer film.

11. Approximately 450 L*m －２ h －１ bar －１ The membrane according to claim 1, characterized by any one of a pure water flow rate of about 450 L*m / h, a flux recovery rate of about 99%, or any combination thereof.

12. The membrane according to claim 1, wherein the polymer membrane is selected from ultrafiltration membranes, nanofiltration membranes, and microfiltration membranes.

13. A coated substrate 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 an acrylate-based polymer, the outer surface of the coating is characterized by a water contact angle of less than about 70°, the crosslinked polymer is characterized by a crosslinking degree of 1-20%, the plurality of particles are characterized by an average particle size of 1 nm to 20 μm, and the coated substrate is water permeable. Coated substrate.

14. The crosslinked polymer is in the form of a matrix, and the plurality of particles are embedded in the matrix or coated by the matrix, the coating substrate according to claim 13.

15. The crosslinked polymer is characterized by a crosslinking degree of 2 to 10%, the coating substrate according to claim 13 or 14.

16. The polymer substrate is in the form of a porous water-permeable film, the coating substrate according to claim 13.

17. The water permeability is at least 10 L·m －２ h －１ bar －１ The coating substrate according to claim 13, which includes a porosity sufficient to support pure water flow with a flux of.

18. The porous water-permeable film is characterized by an average pore diameter of 1 to 10 μm, the coating substrate according to claim 16 or 17.

19. The coating is in the form of a continuous layer characterized by a dry thickness of 50 nm to 20 μm, the coating substrate according to claim 13.

20. The outer surface of the coating is characterized by a negative zeta potential, the coating substrate according to claim 13.

21. The outer surface of the coating is characterized by a surface roughness of 10 to 40 nm, the coating substrate according to claim 13.

22. The weight / weight (w / w) ratio of the particles to the crosslinked polymer in the coating is 1:10 to 10:1, the coating substrate according to claim 13.

23. The polymer substrate includes a surface-modified thermoplastic polymer, the coating substrate according to claim 13.

24. The surface-modified polymer is characterized by a water contact angle at least 10° smaller compared to a similar polymer substrate including an untreated thermoplastic polymer, the coating substrate according to claim 23.

25. The surface-modified polymer is characterized by a water contact angle of less than 70°, the coating substrate according to claim 23 or 24.

26. The thermoplastic polymers include any combination and any copolymer thereof, and are selected from the group consisting of polyacrylonitrile, polyethersulfone, polysulfone, cellulose acetate, polyvinylidene fluoride, polybenzimidazole, intrinsically microporous polymer, and polyolefin, the coating substrate according to claim 13.

27. The outer surface of the coating is characterized by a water contact angle of about 5° to about 50°, the coating substrate according to claim 13.

28. The coating substrate according to claim 13, wherein the particles are crystalline framework structure (CFS) particles.

29. The coating substrate according to claim 28, wherein the CFS particles include zeolite, metal-organic framework (MOF), and covalent organic framework (COF).

30. The coating substrate according to claim 13, wherein the outer surface of the coating is characterized by reduced microbial adhesion thereto as compared to a similar substrate without the coating.

31. The coating substrate according to claim 13, wherein at least 90% of the outer surface is in contact with the coating.

32. A film comprising the coating substrate according to claim 13.

33. The film according to claim 32, which is a water filtration film characterized by a thickness of 10 to 1000 μm.

34. The film according to claim 32 or 33, wherein the film is characterized by a pore size of 2 nm to 100 nm, and optionally, the film is an ultrafiltration membrane.

35. The film according to claim 32, which is characterized by a flux recovery rate of at least 70%.

36. The film according to claim 32, which is characterized by an oil removal of at least 95%.

37. The film according to claim 32, wherein the film retains at least 90% of the initial particle content during continuous water treatment cycles.

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