Membranes and methods for removing trace metals - Patents.com

Abstract

The present disclosure provides certain porous polymeric membranes coated with cross-linked polymerized monomers, including monomers that have an electric charge when immersed in an organic liquid. The membranes of the present disclosure are useful for removing trace amounts of metal impurities, thereby providing ultra-pure organic liquids.

Description

[Technical field]

[0001] FIELD OF THE DISCLOSURE

[0001] This disclosure relates to films useful for removing trace metals from liquids such as solvents, particularly photoresist chemicals. [Background technology]

[0002]

[0002] Filter products are essential tools in modern industry used to remove unwanted materials from useful fluid streams. Useful fluids that are treated using filters include water, liquid industrial solvents and process fluids, industrial gases used in manufacturing or processing (such as semiconductor manufacturing), and liquids for medical or pharmaceutical applications. Unwanted materials removed from liquids include impurities and contaminants such as particles, microorganisms, and dissolved chemical species. Specific examples of filter applications include use with liquid materials for semiconductor and microelectronic device manufacturing.

[0003]

[0003] To perform the filtering function, the filter includes a filter membrane, which serves to remove unwanted materials from the fluid passing through it. The filter membrane may be in the form of a flat sheet, which may be wound (e.g., spirally), flat, pleated, or disk-shaped, as appropriate. Alternatively, the filter membrane may be in the form of a hollow fiber. The filter membrane may be housed in a housing or otherwise supported such that the fluid to be filtered enters through the filter inlet and must pass through the filter membrane before passing through the filter outlet.

[0004]

[0004] Filter membranes can be constructed with a porous structure with an average pore size that can be selected based on the application of the filter, i.e., the type of filtration performed by the filter. Typical pore sizes are in the micron or submicron range, e.g., from about 0.001 micron to about 10 microns. Membranes with an average pore size of about 0.001 to about 0.05 microns are sometimes classified as ultrafiltration membranes. Membranes with a pore size of about 0.05 to 10 microns are sometimes called microporous membranes.

[0005]

[0005] Filter membranes with pore sizes in the micron or submicron range are effective in removing unwanted materials from a fluid stream by sieving or non-sieving mechanisms, or both. Sieving mechanisms are filtration modes that remove particles from a liquid stream by mechanically retaining them on the surface of the filter membrane, which acts to mechanically impede the movement of the particles and retain them within the filter, thus mechanically preventing the flow of particles through the filter. Typically, the particles may be larger than the filter pores. "Non-sieving" filtration mechanisms are filtration modes in which the filter membrane filters suspended particles or dissolved materials contained in the fluid stream in a manner that is not exclusively mechanical, including, for example, electrostatic mechanisms in which particulate or dissolved impurities are electrostatically attracted and retained on the filter surface and removed from the fluid stream. The particles may be dissolved or may be solids with particle sizes smaller than the pores of the filter media.

[0006]

[0006] The removal of ionic substances, such as dissolved anions or cations, from solution is important in many industries, such as the microelectronics industry, where very low concentrations of ionic contaminants or particles can adversely affect the quality and performance of microprocessors and memory devices.

[0007]

[0007] There remains a need for improved methodologies for removing metal contaminants from organic solvents, in particular for materials that allow for the removal of metal contaminants used in the semiconductor processing industry, such as in photoresist applications, where solvents with very low ionic metal contaminant content, i.e., parts per trillion (PPT) levels, are required. Summary of the Invention

[0008] In summary, the present disclosure provides various porous membranes, membrane assemblies, and filter devices capable of removing trace amounts of metal ions from organic liquids. In some embodiments, the organic liquid can be a solvent used in the manufacture of semiconductor and microelectronic devices, including, but not limited to, solvents used in photolithography applications. In certain embodiments, the membranes of the present disclosure are comprised of poly(tetrafluoroethylene), the membranes being at least partially coated with a polymer prepared from the polymerization of at least one monomer and at least one crosslinker, the at least one monomer being selected from a variety of charged monomers. The membrane assemblies of the present disclosure provide improved metal ion removal efficiency, and the devices of the present disclosure perform well, as they have been found to leach only a small amount of various metal ions, surprisingly less than 0.080 ppb, from the porous polymer membranes contained therein when placed in a solvent in idle mode. The results can be compared to data showing leaching of metal ions from similar membranes having UPE polymer backbones, as shown in the examples below. The coatings described herein are prepared from one or more crosslinkers and one or more monomers that comprise, consist of, or consist essentially of the monomers and crosslinkers described herein. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 illustrates an exemplary filter device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010]

[0010] As used in this specification and the appended claims, the singular forms "a," "an," and "the" include plural referents unless the content clearly dictates otherwise. As used in this specification and the appended claims, the term "or" is generally used in its sense including "and / or" unless the content clearly dictates otherwise.

[0011]

[0011] The term "about" generally refers to a range of numbers considered equivalent to a stated value (e.g., having the same function or result). In many cases, the term "about" may include numbers that are rounded to the nearest significant figure.

[0012] Numerical ranges expressed using endpoints include all numbers subsumed within that range (eg, 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, and 5).

[0013] In a first aspect, the present disclosure provides a membrane assembly comprising: a. a porous membrane comprising poly(tetrafluoroethylene) having a coating thereon, the coating being prepared from the polymerization of at least one monomer and at least one crosslinking agent, the monomer having a positive charge in an organic liquid; b. a porous membrane comprising poly(tetrafluoroethylene), said membrane having a coating thereon, said coating being prepared from the polymerization of at least one monomer and at least one crosslinking agent, said monomer having a negative charge in an organic liquid; Including, The assembly provides a membrane assembly that exhibits greater than 90% total removal efficiency of one or more metal ions selected from lithium, boron, sodium, magnesium, aluminum, potassium, calcium, titanium, vanadium, chromium, manganese, iron, nickel, copper, zinc, molybdenum, silver, tin, barium, and lead ions from a feed stream containing 1 ppb of the metal ion selected from lithium, boron, sodium, magnesium, aluminum, potassium, calcium, titanium, vanadium, chromium, manganese, iron, nickel, copper, zinc, molybdenum, silver, tin, barium, and lead ions.

[0014]

[0014] The membrane assemblies referred to herein are generally pleated packs of two or more membranes stacked together through which the organic liquid passes during operation. Optionally, support materials such as polymeric screens can be placed between the membranes.

[0015] As mentioned above, the porous polytetrafluoroethylene (PTFE) membranes modified herein have been found to provide purified solvents. The underlying PTFE membranes are commercially available and widely available in the market. The PTFE membranes described herein can have a variety of geometric configurations, such as flat sheets, corrugated sheets, pleated sheets, hollow fibers, etc. The porous membranes can have pore structures that are isotropic or anisotropic, skinned or unskinned, symmetrical or asymmetrical, any combination thereof, or can be composite membranes that include one or more retaining layers and one or more supporting layers. Furthermore, the coated porous membranes can be supported or unsupported by webs, nets, cages, etc.

[0016]

[0016] To prepare the membranes of the present disclosure, the methodology of U.S. Patent Publication No. 2020 / 0206691, the entirety of which is incorporated by reference herein, can be utilized.

[0017] That is, specific functional groups having a positive or negative charge can be introduced onto the surface of a polymer membrane by coating the membrane with a coating having the desired pendant functional group.

[0018]

[0018] Generally, the coating is composed of an organic backbone formed from a specific polymerized monomer. Thus, the coating can be prepared from various monomers having at least one carbon-carbon double bond, including a monomer and a crosslinking agent, by initiating a free radical polymerization reaction, and then providing the coating on the surface of the PTFE membrane. The crosslinking agent is generally a difunctional monomer. The polymerization and crosslinking of the polymerizable monomer onto the porous membrane substrate is carried out such that at least a portion to the entire surface of the porous membrane, including the inner pore surface of the porous membrane, is modified with a crosslinked polymer coating. Therefore, it should be understood that the present disclosure encompasses coating a desired portion (greater than 0% to 100%) of the surface of the porous membrane with a crosslinked polymer composition.

[0019] Exemplary monomers having a positive charge in an organic liquid that can be used for coating in embodiments of the present disclosure include, but are not limited to, 2-(dimethylamino)ethyl acrylate hydrochloride, [2-(acryloyloxy)ethyl]trimethylammonium chloride, 2-aminoethyl methacrylate hydrochloride, N-(3-aminopropyl)methacrylate hydrochloride, 2-(dimethylamino)ethyl methacrylate hydrochloride, [3-(methacryloylamino)propyl]trimethylammonium chloride solution, [2-(methacryloyloxy)ethyl]trimethylammonium chloride, acrylamidopropyltrimethylammonium chloride, 2-aminoethyl methacrylamide hydrochloride, N-(2-aminoethyl)methacrylamide hydrochloride, N-(3-aminopropyl)methacrylamide hydrochloride, diallyldimethylammonium chloride, vinylbenzyltrimethylammonium chloride, allylamine hydrochloride, vinylimidazolium hydrochloride, vinylpyridinium hydrochloride, and vinylbenzyltrimethylammonium chloride, either alone or in combination of two or more thereof. It should be understood that some of the positively charged monomers listed above contain quaternary ammonium groups and are naturally charged in organic solvents, while other positively charged monomers, such as those containing primary, secondary, and tertiary amines, are adjusted to generate a charge by treatment with an acid. Monomers that can be naturally or by treatment positively charged in organic solvents can be polymerized and crosslinked with a crosslinker to form a coating on the porous membrane that is also positively charged when in contact with an organic solvent. In certain embodiments, the monomers that are positively charged in organic liquids are selected from diallyl dimethyl ammonium chloride, diallyl dimethyl ammonium bromide, acrylamidopropyl trimethyl ammonium chloride (CAS number 7398-69-8), acrylamidopropyl trimethyl ammonium bromide, vinylbenzyl trimethyl ammonium chloride (CAS number 26616-35-3), and vinylbenzyl trimethyl ammonium bromide. In certain embodiments, the coating is prepared from the polymerization of diallyl dimethyl ammonium chloride and at least one crosslinker.It should be understood that some of these monomers contain quaternary ammonium groups and are naturally charged in polar solvents, while other monomers with positive charges, such as those containing primary, secondary, and tertiary amines, can be adjusted to generate a charge by treatment with acid. It should also be understood that the free radically polymerized coatings can be prepared using the chloride or hydrochloride forms of the above monomers, or can be converted to different halide or hydrogen halide forms, or converted to hydroxide forms prior to polymerization. Thus, this list of monomers is intended to include variations of the associated anions, i.e., different halides or different halides. In certain embodiments, the coatings are prepared from monomers that include, consist of, or consist essentially of the positively charged monomers described herein (and are used in combination with one or more crosslinkers).

[0020] In a particular embodiment, the coating on the porous PTFE membrane is prepared from a polymerized monomer having a positive charge. It is to be understood that the embodiments of the present disclosure may include multiple polymerized monomers having different (copolymer) or the same (homopolymer) positive charges. In one embodiment, some of the multiple polymerized monomers having a positive charge are the same. In another particular embodiment, some of the multiple polymerized monomers having a positive charge are different from each other. The multiple polymerized monomers having a positive charge may have one or more properties that are different or similar from each other. In a particular embodiment of such a coating, one or more of the polymerized monomers are different from each other to form a copolymer having a positive charge that is crosslinked to other polymerized monomers by a crosslinking agent.

[0021] Examples of negatively charged monomers in organic liquids that can be used for coating include, but are not limited to, 2-ethylacrylic acid, acrylic acid, 2-carboxyethyl acrylate, 3-sulfopropyl acrylate potassium salt, 2-propylacrylic acid, 2-(trifluoromethyl)acrylic acid, methacrylic acid, 2-methyl-2-propene-1-sulfonic acid sodium salt, mono-2-(methacryloyloxy)ethyl maleate, 3-sulfopropyl methacrylate potassium salt, 2-acrylamido-2-methyl-1-propanesulfonic acid, 3-methacrylamidophenylboronic acid, vinylsulfonic acid, vinylphosphonic acid, either alone or in combination of two or more thereof. In certain embodiments, the negatively charged monomer comprises a sulfonic acid. It should be understood that some of the negatively charged monomers listed above contain strong acid groups and are naturally charged in organic solvents, while other negatively charged monomers containing weak acids are adjusted to generate a charge by base treatment. Monomers that are naturally or by treatment negatively charged in organic solvents can be polymerized and crosslinked with at least one crosslinker to form a coating on the porous membrane that is negatively charged in organic solvents. In certain embodiments, the coating is prepared from a monomer selected from 2-methyl-2-propene-1-sulfonic acid salts (such as sodium salts), 2-acrylamido-2-methyl-1-propanesulfonic acid, vinylsulfonic acid, and vinylphosphonic acid, or a salt thereof, and at least one crosslinker.

[0022] In one embodiment, the coating is prepared from a plurality of polymerized monomers having a negative charge. In one embodiment, the coating is prepared from a plurality of polymerized monomers having a negative charge. In one embodiment, the plurality of monomers having a negative charge are the same. In another particular embodiment, the plurality of monomers having a negative charge are different from each other. The plurality of monomers having a negative charge may have one or more properties that are different or similar to each other. In an embodiment of the coating, one or more polymerized monomers having a negative charge are crosslinked with one or more other polymerized monomers having a negative charge. In another embodiment, the coating can be prepared from a combination of positively charged polymerized monomers and negatively charged polymerized monomers crosslinked on the same membrane or on separate membranes. In another embodiment, a porous membrane is coated with crosslinked polymerized monomers having a positive charge, and another separate porous membrane includes crosslinked polymerized monomers having a negative charge. In another embodiment, coatings with positively and negatively charged polymerized monomers are crosslinked and formed on the same porous polymer membrane. In yet another embodiment, the coatings including crosslinked polymerized monomers include monomers that are zwitterionic and have both positive and negative charges on the same monomer in an organic liquid.

[0023]

[0023] Zwitterionic monomers have both positive and negative charges in the same monomer backbone. Non-limiting examples of zwitterionic monomers that can be polymerized and crosslinked on the surface of the membrane include [3-(methacryloylamino)propyl]dimethyl(3-sulfopropyl)ammonium hydroxide, [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl)ammonium hydroxide, 2-(methacryloyloxy)ethyl 2-(trimethylammonio)ethyl phosphate, 1-(3-sulfopropyl)-2-vinylpyridinium hydroxide, and combinations thereof.

[0024] In a further embodiment, a portion of the uncharged monomer from about 0 to about 10 weight percent can be utilized in the polymerization reaction (based on the total weight of the reaction solution). Such monomers are generally ethylenically unsaturated monomers selected from acrylic and methacrylic acid esters, and vinyl compounds.

[0025] The crosslinking agents are uncharged difunctional (i.e., having two carbon-carbon double bonds) vinyl, acrylic or methacrylic monomer species, optionally with amide functionality. Non-limiting examples of such crosslinking agents include methylene bis(acrylamide), tetraethylene glycol diacrylate, tetraethylene glycol dimethacrylate, divinyl sulfone, divinyl benzene, 1,3,5-triallyl-1,3,5-triazine-2,4,6(1H,3H,5H)-trione 98%, ethylene glycol divinyl ether, divinyl polyethylene glycol, and triallyl amine.

[0026]

[0026] By way of example, polymerization and crosslinking of polymerizable monomers onto a porous membrane substrate can be carried out such that selected portions of the porous membrane or the entire surface, including the inner surface of the porous membrane, are modified with the crosslinked polymer.

[0027] For the free radical polymerization reaction to form the coating, the reagent bath is composed of: (1) at least one polymerizable monomer that is ethylenically unsaturated and has at least one charged moiety; (2) optionally a polymerization initiator; and (3) a crosslinking agent in a polar solvent, such as a water-soluble solvent for these three components, contacted with the porous polymer membrane substrate under conditions that result in polymerization and crosslinking of the monomer and deposition of the resulting crosslinked polymer on the porous polymer membrane substrate. Even if the solvent is a polar solvent, the required degree of membrane surface modification may be obtained. If the monomer is difunctional or has higher functionality, an additional crosslinking agent is not required, but may be used. Representative suitable polar solvents include solvents with a dielectric constant greater than 25° C. at room temperature, such as polyols, such as 2-methyl-2,4-pentanediol, 2,4-pentanedione, glycerin, or 2,2′-thiodiethanol; amides, such as formamide, dimethylformamide, dimethylacetamide; alcohols, such as methanol; and nitro-substituted aromatic compounds, such as nitrobenzene, 2-furaldehyde, acetonitrile, 1-methylpyrrolidone. A particular solvent is selected to dissolve the crosslinker, monomer, and initiator (if present).

[0028]

[0028] An initiator suitable for the above-mentioned monomers and crosslinking agents can be used. For example, suitable photoinitiators include benzophenone, 4-(2-hydroxyethoxy)phenyl-(2-hydroxy-2-propyl)ketone, azoisopropane, or 2,2-dimethoxy-2-phenylacetophenone. Suitable thermal initiators include organic peroxides such as dibenzoyl peroxide, t-butyl hydroperoxide, cumyl peroxide, t-butyl perbenzoate, and azo compounds such as azobisisobutyronitrile (AIBN) or 4,4,'-azobis(4-cyanovaleric acid).

[0029] In certain embodiments, the polymerizable monomer is present in the reaction solution at a concentration of about 2% to about 20%, or about 5% to about 10%, based on the weight of the total solution. The crosslinker is present in an amount between about 2% and about 10%, based on the weight of the polymerizable monomer. Larger amounts of crosslinker can be used. The polymerization initiator is present in an amount between about 1% and about 10%, based on the weight of the polymerizable monomer. As mentioned above, the crosslinker can be utilized without a monomer, thereby functioning as a polymerizable monomer.

[0030] In certain embodiments, the H of the negatively charged membrane of the present disclosure, as measured by titration of ionizable groups, + The ion exchange capacity is about 1 to about 100, about 1 to about 40, or about 1 to about 10 meq H + / m 2 (meq = milliequivalent). Similarly, the positive and negative OH groups of the membrane, measured by titration of ionizable groups, - The ion exchange capacity is about 1 to about 100, about 1 to about 40, or about 1 to about 10 meq H + / m 2 It is a membrane.

[0031] Polymerization and crosslinking can be achieved by exposing the monomer reaction system to ultraviolet (UV) light, a heat source, or ionizing radiation. Polymerization and crosslinking are carried out in an environment where oxygen does not inhibit polymerization or crosslinking. This process can be carried out simply by immersing the film substrate in a solution containing the monomer, crosslinker, and initiator, and sandwiching the film between two UV-transmitting sheets such as polyethylene, or under a blanket of inert gas such as nitrogen, and exposing to UV light. This process can be carried out continuously, and once UV exposure is initiated, the desired crosslinked coating is formed. As mentioned above, the coated film is produced by controlling the reactant concentration and UV exposure.

[0032]

[0032] Thus, in a further aspect, the present disclosure provides a porous membrane comprising poly(tetrafluoroethylene), wherein the membrane has a coating, the coating being prepared from the polymerization of at least one monomer and at least one crosslinking agent, the monomer having a positive charge in an organic liquid. In one embodiment, the monomer is a quaternary ammonium compound having at least one carbon-carbon double bond. In another embodiment, the quaternary ammonium compound is selected from diallyldimethylammonium halides, such as diallyldimethylammonium chloride or diallyldimethylammonium bromide, or vinylbenzyltrimethylammonium chloride or vinylbenzyltrimethylammonium bromide. In a further embodiment, the at least one monomer further comprises a monomer having a negative charge in an organic liquid.

[0033]

[0033] The membranes of the present disclosure may be used individually, or as a combination or assembly of two or more membranes, if desired. As shown in the examples below, a membrane having a positive charge and another membrane having a negative charge used together as a membrane assembly showed superior performance in the removal efficiency of various metal ion contaminants in various organic liquids. Thus, in a further aspect, the present disclosure provides a membrane assembly comprising: a. a porous membrane comprising poly(tetrafluoroethylene) having a coating thereon, the coating being prepared from the polymerization of at least one monomer and at least one crosslinking agent, the monomer having a positive charge in an organic liquid; b. a porous membrane comprising poly(tetrafluoroethylene) and having a coating thereon, the coating being prepared from the polymerization of at least one monomer and at least one crosslinking agent, the monomer having a negative charge in an organic liquid; Including, The membrane assembly exhibits greater than 90% total removal efficiency of one or more metal ions selected from lithium, boron, sodium, magnesium, aluminum, potassium, calcium, titanium, vanadium, chromium, manganese, iron, nickel, copper, zinc, molybdenum, silver, tin, barium, and lead ions from a feed stream containing 1 ppb of metal ions selected from lithium, boron, sodium, magnesium, aluminum, potassium, calcium, titanium, vanadium, chromium, manganese, iron, nickel, copper, zinc, molybdenum, silver, tin, barium, and lead ions.

[0034]

[0034] As shown in the examples below, filter devices including positive and negative electrode membranes have also been shown to significantly reduce leaching of certain metal ions believed to be from the polymer backbone of the membranes. Thus, in a further aspect, the present disclosure provides: a. a porous membrane comprising poly(tetrafluoroethylene), the membrane having a coating thereon, the coating being prepared from the polymerization of at least one monomer and at least one crosslinking agent, the monomer forming a positively charged porous membrane in an organic liquid; b. A porous membrane having a coating thereon, the coating comprising poly(tetrafluoroethylene), the coating being prepared from the polymerization of at least one monomer and at least one crosslinking agent, the monomer being negatively charged in an organic liquid; a plurality of membranes comprising Generate less than 0.080 ppb of metal ions selected from sodium, magnesium, aluminum, potassium, calcium, iron, and zinc ions when immersed in a PGME / PGMEA solution (70:30 by volume) for 8 hours A filter device is provided.

[0035] It should also be understood that the method of the present disclosure includes removing metal contaminants from a range of organic liquids, which may be liquids, either alone or in combination of two or more. Non-limiting examples of organic liquids include cyclohexanone, isopentyl ether, propylene glycol monomethyl ether acetate (PGMEA), methyl isobutyl carbinol, N-butyl acetate, methyl-2-hydroxyisobutyrate, a mixture of propylene glycol monomethyl ether (PGME) and PGMEA (mixing ratio 7:3, surface tension 27.7 mN / m), either alone or in combination of two or more. Particular embodiments include, but are not limited to, water-immiscible organic liquids, such as cyclohexanone and PGMEA. In one embodiment, water-immiscible means that it dissolves in water up to 19.8 g per 100 ml of water.

[0036]

[0036] Therefore, the membranes, membrane assemblies, and filter devices of the present invention are useful for removing metal ion contaminants from organic liquids. Embodiments of the present disclosure include removing metal contaminants from a combination of different organic liquids. Particular embodiments include solvents used in photoresists. Examples of solvents used in photoresists include, but are not limited to, liquids such as methyl amyl ketone, ethyl-3-ethoxypropionate, propylene glycol methyl ether (PGME), propylene glycol methyl ether acetate (PGMEA), methanol, ethyl acetate, ethyl lactate, and the like, which may be used alone or in combination of two or more.

[0037]

[0037] The methods of the present disclosure are not limited by the order, frequency, or sequence of the various acts or steps, unless specified, and may be repeated as necessary.

[0038] As stated above, the method is not limited to any particular order or sequence, and may be repeated as necessary, unless otherwise specified. In another embodiment, the membrane having the cross-linking monomer with a negative charge is the first membrane, and the membrane having the cross-linking monomer with a positive charge is the second membrane. Furthermore, a combination of polymerized monomers with positive and negative charges may be coated onto the porous polymeric membrane. In another embodiment, the coating with polymerized monomers with positive and negative charges is on the same membrane. In one embodiment, the first membrane of the two-layer membrane stack may include a coating with polymerized monomers with positive and negative charges on the same membrane. In another embodiment, the second membrane of the two-layer membrane stack may include a coating with polymerized monomers with positive and negative charges on the same membrane. Unless otherwise specified, the sequence, frequency, or order may be altered. It should be understood that the first and second membranes may effectively remove metal contaminants differently or with different efficiencies from each other.

[0039] Another embodiment includes a method of removing metal contaminants from an organic liquid by passing the organic liquid through a porous polymeric membrane assembly having multiple layers. The porous polymeric membrane assembly includes a first layer (or membrane) and a second layer (or membrane). The first layer includes a coating including one or more cross-linked polymerized monomers having a positive charge. The second layer includes a coating including one or more cross-linked polymerized monomers having a negative charge. The organic liquid has a low concentration of metal contaminants after passing through the porous polymeric membrane. In certain embodiments, the organic liquid includes a liquid used in photoresists. A combination of polymerized monomers having positive and negative charges can be coated onto a layer of the polymeric membrane. It should be understood that different layers of the membrane and the apparatus containing the membrane can effectively remove metal contaminants differently or with different efficiencies from one another.

[0040] In a particular embodiment, the metal contaminants removed include Li, Na, Mg, Al, K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Sr, Mo, Ag, Cd, Sn, Ba, and Pb ions, either alone or in combination of two or more. In another embodiment, metal contaminants such as Al, Ca, Cr, Cu, Fe, Pb, Mg, Mn, Ni, K, Na, Sn, Ti, and Zn are removed either alone or in combination of two or more. In a particular embodiment, metal contaminants such as Fe, Ni, Cr, Cu, and Al are removed either individually or in combination of two or more. In one embodiment, metal contaminants such as Fe, Ni, and Cr are removed either individually or in combination of two or more. In one embodiment, the removal efficiency of metal contaminants such as Al, Ca, Cr, Cu, Fe, Pb, Mg, Mn, Ni, K, Na, Sn, Ti, Zn, etc., for removing metal contaminants from a water-immiscible organic liquid after passing the water-immiscible organic liquid through a porous membrane or porous membrane assembly is about 90%, about 92%, about 95%, or about 97% for removing metal contaminants from a water-immiscible organic liquid. In the example shown below, the removal efficiency of metal contaminants from a water-immiscible organic liquid is about 90%, about 92%, about 95%, or about 97% for removing metal contaminants from a water-immiscible organic liquid when the membrane area is 1000 cm. 2 The apparatus was filled with 1200 ml of each liquid solution. In certain embodiments, the metal contaminant removal efficiency is greater than 90%, 92%, 95%, 97%, and approaches 100%, as detailed in Table 2 below. In other words, the metal contaminant concentration in the organic liquid feed stream for one or more of the metal species listed above is reduced by about 99%, 98%, 97%, 96, 95%, 94%, 93%, 92%, 91%, 90%, or 85% of the initial feed concentration after passing through one or more of the coated porous PTFE membranes. In some embodiments, the metal contaminant concentration in the organic liquid feed stream is 150 ppbv / v or less, and the removal of metal contaminants is greater than 1000 cm as described herein. 2 The concentration of metal contaminants is measured by passing an organic liquid feed stream through an apparatus containing a porous membrane coated with 100% ethanol at a flow rate of 60 milliliters per minute (ml / min) and measuring the treated organic liquid output. In both cases, references herein to metal contaminants include both metallic (i.e., zero valent) and ionic metal contaminants.

[0041] In some embodiments, as shown in Example 6 below, a filter device including one or more coated porous PTFE membranes produces less than 0.080 ppb of at least one metal ion selected from sodium, magnesium, aluminum, potassium, calcium, iron, and zinc ions when immersed in a PGME / PGMEA solution (70:30 by volume) for 8 hours. In some embodiments, a filter device so immersed for 8 hours produces less than 0.080 ppb of each metal ion selected from sodium, magnesium, aluminum, potassium, calcium, iron, and zinc ions.

[0042]

[0042] In another aspect, the present invention provides a filtration device comprising one or more of the membranes of the present invention. An example of a filter structure comprising a pleated cylindrically coated filter membrane can be prepared to include the following components, any of which may be included in the filter structure but may not be required: a rigid or semi-rigid core supporting the pleated cylindrically coated filter membrane at the inner opening of the pleated cylindrically coated filter membrane; a rigid or semi-rigid cage supporting or surrounding the exterior of the pleated cylindrically coated filter membrane at the exterior of the pleated cylindrically coated filter membrane; an optional end piece or "pack" disposed at each of the two opposite ends of the pleated cylindrically coated filter membrane; and a filter housing including an inlet and an outlet. The filter housing can be of any useful and desired size, shape, and material, and can preferably be made of a suitable polymeric material.

[0043]

[0043] As an example, FIG. 1 shows a filter component 30 that is comprised of a pleated cylindrical component 10, an end piece 22, and other optional components. The cylindrical component 10 includes a filter membrane 12, as described herein, and is pleated. In some embodiments, the filter membrane 12 is a membrane assembly of multiple membranes with optional separator material disposed between the individual membranes. The end piece 22 is attached (e.g., "potted") to one end of the cylindrical filter component 10. The end piece 22 can preferably be made of a melt-processable polymeric material. A core (not shown) can be disposed in the interior opening 24 of the pleated cylindrical component 10, and a cage (not shown) can be disposed on the exterior of the pleated cylindrical component 10. A second end piece (not shown) can be attached ("potted") to a second end of the pleated cylindrical component 30. The resulting pleated cylindrical component 30, including two opposing potted ends and an optional core and cage, is placed into a filter housing that includes an inlet and an outlet, because all fluid entering the inlet must pass through the filtration membrane 12 before exiting the filter through the outlet.

[0044]

[0044] Example

[0045] Example 1

[0046] This example demonstrates how to modify the surface of a porous polyethylene (UPE) membrane with a coating containing polymerized monomers that carry a negative charge (negative UPE membrane).

[0045]

[0047] A surface modification monomer solution was made containing the following components: 0.3% Irgacure 2959, 6% methanol, 5.6% acrylamidomethylpropanesulfonic acid (AMPS), 2.5% methylenebisacrylamide (MBAm) crosslinker, and 85.6% water (the percentages in these examples are weight percents based on the total weight of the polymerization solution mixture).

[0046]

[0048] Porous UPE membranes surface-modified with a coating having a negatively charged polymerized monomer are produced by the following method. First, a disk of 47 mm UPE porous membrane (84 μm thick, average bubble point 27 psi in isopropanol (IPA), Entegris, Inc.) was wetted with IPA solution for 25 seconds. (In the bubble point test method, a sample of porous polymer filter membrane is immersed and wetted in a liquid with known surface tension, and gas pressure is applied to one side of the sample.) The gas pressure is gradually increased. The minimum pressure at which gas flows through the sample is called the bubble point. To determine the bubble point of a porous material, a sample of the porous material is immersed and wetted in isopropanol at a temperature of 20-25 °C (e.g., 22 °C). Gas pressure is applied to one side of the sample using compressed air, and the gas pressure is gradually increased. The membrane was then washed using an exchange solution containing 10% hexylene glycol and 90% water to remove the IPA. The porous membrane disk was then introduced into the surface modification monomer solution and left submerged for 2 minutes. The porous membrane disk was removed from the surface modification monomer solution and placed between clear polyethylene sheets. Excess solution was removed by laying the polyethylene / membrane disk / polyethylene sandwich flat on a table and rolling a rubber roller over it. The polyethylene sandwich was then taped to a transport unit and the assembly was transported through a Fusion Systems broadband UV exposure experimental unit that emits wavelengths from 200 to 600 nm. The exposure time was controlled by the speed at which the assembly passed through the UV unit. In this example, the assembly was moved through the UV chamber at a speed of 10 feet per minute. After exiting the UV unit, the membrane was removed from the sandwich and immediately placed in DI water and allowed to soak for 5 minutes. The treated membrane sample was then transferred to methanol and allowed to soak for 5 minutes. After this soaking procedure, the membrane was allowed to dry on a holder in an oven operated at 50 °C for 10 minutes. The water flow time for the membrane modified as described above was 400 seconds / 500 mL. H + The ion exchange capacity is measured by titration of ionizable groups and is 2 4.2 meq H per +(meq = milliequivalents). The resulting membrane is hydrophilic and spontaneously wets when submerged in deionized water.

[0047]

[0049] Example 2

[0050] This example shows how to modify the surface of a porous polyethylene (UPE) membrane with a coating containing a polymerized monomer that has a positive charge (positive UPE membrane). A surface modification monomer solution was made containing the following components: 0.3% Irgacure 2959, 10% methanol, 5.5% (3-acrylamidopropyl)trimethylammonium chloride (APTAC), 2.0% N,N-dimethylacrylamide (DMAM), 1.5% methylenebisacrylamide (MBAm) crosslinker, and 80.7% water.

[0048]

[0051] Porous PTFE membranes surface modified with a coating having a negatively charged polymerized monomer are produced by the following method. First, a 47 mm disk of PTFE porous membrane (84 um thick, 27 psi average bubble point in IPA) is wetted with IPA solution for 25 seconds. The membrane is then washed using an exchange solution containing 10% hexylene glycol and 90% water to remove the IPA. The porous membrane disk is then introduced into the surface modification monomer solution and left submerged for 2 minutes. The porous membrane disk is removed from the surface modification monomer solution and placed between clear polyethylene sheets. Excess solution is removed by laying the polyethylene / membrane disk / polyethylene sandwich flat on a table and rolling a rubber roller over it. The polyethylene sandwich is then taped to a transport unit and the assembly is transported through a Fusion Systems broadband UV exposure experimental unit emitting wavelengths between 200 and 600 nm. Exposure time was controlled by the speed at which the assembly passed through the UV unit. In this example, the assembly was moved through the UV chamber at a speed of 10 feet per minute. After coming out of the UV unit, the membrane was removed from the sandwich and immediately placed in DI water and allowed to soak for 5 minutes. The treated membrane sample was then transferred to methanol and allowed to soak for 5 minutes. After this soaking procedure, the membrane was dried on a holder in an oven operated at 50°C for 10 minutes. The water flow time for the membrane modified as above was 780 seconds / 500 mL. OH - The ion exchange capacity was determined by titration of ionizable groups and was 2.5 meq OH. - / m 2 The resulting membrane was determined to be hydrophilic and spontaneously wetted when submerged in deionized water.

[0049]

[0052] Example 3

[0053] This example demonstrates how to modify the surface of a porous polytetrafluoroethylene (PTFE) membrane with a coating having a polymerized monomer that has a negative charge (negatively charged PTFE membrane).

[0050]

[0054] A surface modification monomer solution was made containing the following components: 0.3% Irgacure 2959, 10% methanol, 5.6% acrylamidomethylpropanesulfonic acid (AMPS), 2.5% methylenebisacrylamide (MBAm) crosslinker, and 81.6% water (by weight).

[0051]

[0055] Porous PTFE membranes surface modified with a coating having a negatively charged polymerized monomer are produced by the following method. First, a disk of 47 mm PTFE porous membrane (60 um thick, 25 psi average bubble point in IPA) is wetted with IPA solution for 25 seconds. The membrane is then washed using an exchange solution containing 10% hexylene glycol and 90% water to remove the IPA. The porous membrane disk is then introduced into the surface modification monomer solution and left submerged for 2 minutes. The porous membrane disk is removed from the surface modification monomer solution and placed between clear polyethylene sheets. Excess solution is removed by laying the polyethylene / membrane disk / polyethylene sandwich flat on a table and rolling a rubber roller over it. The polyethylene sandwich is then taped to a transport unit and the assembly is transported through a Fusion Systems broadband UV exposure experimental unit that emits wavelengths between 200 and 600 nm. Exposure time was controlled by the speed at which the assembly passed through the UV unit. In this example, the assembly was moved through the UV chamber at a speed of 10 feet per minute. After exiting the UV unit, the membrane was removed from the sandwich and immediately placed in DI water and allowed to soak for 5 minutes. The treated membrane sample was then transferred to methanol and allowed to soak for 5 minutes. After this soaking procedure, the membrane was dried on a holder in an oven operated at 50°C for 10 minutes. The water flow time for the membrane modified as above was 250 seconds / 500 mL. + The ion exchange capacity was determined by titration of ionizable groups and was found to be 3.2 meq H+ / m 2 The resulting membrane was determined to be hydrophilic and spontaneously wetted when submerged in deionized water.

[0052]

[0056] Example 4

[0057] This example demonstrates how to modify the surface of a porous polytetrafluoroethylene (PTFE) membrane with a coating having a polymerized monomer with a positive charge (positive PTFE membrane).

[0053]

[0058] A surface modification monomer solution was made containing the following components: 0.3% Irgacure 2959, 10% methanol, 4% (3-acrylamidopropyl)trimethylammonium chloride (APTAC), 4% diallyldimethylammonium chloride (DADMAC), 2.5% methylenebisacrylamide (MBAm) crosslinker, and 79.2% water.

[0054]

[0059] Porous PTFE membranes surface modified with a coating having a negatively charged polymerized monomer are produced by the following method. First, a 47 mm disk of PTFE porous membrane (60 um thick, 24 psi average bubble point in IPA) is wetted with IPA solution for 25 seconds. The membrane is then washed using an exchange solution containing 10% hexylene glycol and 90% water to remove the IPA. The porous membrane disk is then introduced into the surface modification monomer solution and left submerged for 2 minutes. The porous membrane disk is removed from the surface modification monomer solution and placed between clear polyethylene sheets. Excess solution is removed by laying the polyethylene / membrane disk / polyethylene sandwich flat on a table and rolling a rubber roller over it. The polyethylene sandwich is then taped to a transport unit and the assembly is transported through a Fusion Systems broadband UV exposure experimental unit that emits wavelengths between 200 and 600 nm. Exposure time was controlled by the speed at which the assembly passed through the UV unit. In this example, the assembly was moved through the UV chamber at a speed of 10 feet per minute. After coming out of the UV unit, the membrane was removed from the sandwich and immediately placed in DI water and allowed to soak for 5 minutes. The treated membrane sample was then transferred to methanol and allowed to soak for 5 minutes. After this soaking procedure, the membrane was dried on a holder in an oven operated at 50°C for 10 minutes. The water flow rate of the membrane modified as above was 370 sec / 500 mL. OH -The ion exchange capacity was determined by titration of ionizable groups and was 3.2 meq OH. - / m 2 The resulting membrane was determined to be hydrophilic and spontaneously wetted when submerged in deionized water.

[0055]

[0060] Example 5: Metal Removal Efficiency in Various Photolithography Solvents

[0061] This example demonstrates the ability of a porous polyethylene (UPE) membrane surface-modified with a coating having a polymerized monomer with a negative charge, a porous UPE membrane surface-modified with a coating having a polymerized monomer with a positive charge, and a membrane assembly of a porous polytetrafluoroethylene (PTFE) membrane surface-modified with a coating having a polymerized monomer with a negative charge and a porous polytetrafluoroethylene (PTFE) membrane surface-modified with a coating having a polymerized monomer with a positive charge to reduce metals in solvents commonly used in photolithography.

[0056]

[0062] 47 mm coupons of different purifiers, negative UPE membrane (prepared according to Example 1), positive UPE membrane (prepared according to Example 2), and positive PTFE membrane (prepared according to Example 4) / negative PTFE membrane (prepared according to Example 3) assemblies were used to evaluate metal removal performance in different polar and non-polar solvents such as propylene glycol methyl ether (PGME) / propylene glycol methyl ethyl acetate (PGMEA) (70 / 30), propylene glycol methyl ethyl acetate (PGMEA), cyclohexanone (CHN), and n-butyl acetate (n-BA). The purification membrane assemblies were first pre-cleaned and then mounted on clean PFA (perfluoroalkoxy) coupon holders. Each test solvent was spiked with a known concentration (1 ppb containing 21 metals) using Conostan® OilStandard S-21 from SCP Science. Samples were collected downstream of the purification membrane assemblies at volume intervals of 50 mL, 100 mL, and 150 mL. Feed and filtrate samples were analyzed using an Agilent ICPMS 8900 to evaluate metal removal performance among the three purification devices. Results are shown in percent removal in Tables 1a-d for individual metals and in Table 2 for total metals. From the data presented below, the positive PTFE membrane / negative PTFE membrane performs as well or better than the negative and positive UPE membranes for all metals in all solvents tested. Table 2 summarizes the average total metal removal efficiencies in various solvents commonly used in photolithography. While the positive UPE membrane can remove a subset of metals from various solvents and the negative UPE membrane can also remove a subset of metals from various solvents, the positive PTFE membrane / negative PTFE membrane metal purification membrane assembly can achieve removal efficiencies of over 90% across a wide range of solvent polarities.

[0057]

[0063] Total metal concentration in 150 ml of filtrate (spiked at 1 ppb of each metal)

[0064] Table 1a PGME / PGMEA (70 / 30; volume:volume) TIFF2025505426000002.tif111170

[0058]

[0065] Table 1b PGMEA TIFF2025505426000003.tif111170

[0059]

[0066] Table 1c n-Butyl acetate TIFF2025505426000004.tif111170

[0060]

[0067] Table 1d Cyclohexanone TIFF2025505426000005.tif111170

[0061]

[0068] Table 2: Comparison of metal removal efficiency of negative UPE membranes, positive UPE membranes, and positive PTFE membranes / negative PTFE membranes TIFF2025505426000006.tif51170

[0062]

[0069] As shown in the table above, the combination of the positive and negative PTFE membranes unexpectedly demonstrated superior metal removal efficiency and total metal removal efficiency over the UPE membrane.

[0063]

[0070] Example 6: Idle Immersion Study

[0071] A new assembly of negative UPE membrane (made according to Example 1) and positive PTFE membrane (made according to Example 4) / negative PTFE membrane (made according to Example 3) was placed in an Optimizer® D capsule (Entegris, Inc.) format, immersed in PGME / PGMEA (70 / 30) and left idle for periods of time (1 hour, 8 hours, and 24 hours) to investigate metal leaching from an idle purifier. Both purifiers were filled with solvent and left to soak for the first hour. After 1 hour, samples were taken for ICPMS analysis. Then, both lines and the Optimizer D were emptied and filled with a new blend of PGME / PGMEA (70 / 30) and left to soak for 8 hours and finally for 24 hours. Samples were tested using an Agilent ICPMS 8900. Table 3 below shows the metal leaching behavior over time between the negative UPE membrane and the positive PTFE membrane / negative PTFE membrane when removing metal ions of Na, Mg, Al, K, Ca, Fe, and Zn under idle soak conditions in PGME / PGMEA (70 / 30). The negative UPE membrane shows significant metal levels at 1 hour compared to the positive PTFE membrane / negative PTFE membrane for common metals such as Fe, Zn, and Ca. In the case of the negative UPE membrane, metals appear to be leached even after 24 hours of soaking, while the positive PTFE membrane / negative PTFE membrane does not show any metal leaching behavior over time, with the same levels of metals seen from 1 hour to 8 hours and up to 24 hours.

[0064]

[0072] Table 3: TIFF2025505426000007.tif47170

[0065]

[0073] As shown in Table 3, the combination of the positive and negative PTFE membranes unexpectedly had better overall leaching behavior than the UPE membranes.

[0066]

[0074] Aspects

[0075] In a first aspect, the present disclosure provides a method for producing a method for manufacturing a pharmaceutical composition comprising: a. a porous membrane comprising poly(tetrafluoroethylene), the membrane having a coating thereon, the coating being prepared from the polymerization of at least one monomer and at least one crosslinking agent, the monomer having a positive charge in an organic liquid; b. A porous membrane comprising poly(tetrafluoroethylene), the membrane having a coating thereon, the coating being prepared from the polymerization of at least one monomer and at least one crosslinking agent, the monomer forming a negative charge in an organic liquid. a plurality of membranes comprising A membrane assembly is provided that exhibits greater than 90% total removal efficiency of one or more metal ions selected from lithium, boron, sodium, magnesium, aluminum, potassium, calcium, titanium, vanadium, chromium, manganese, iron, nickel, copper, zinc, molybdenum, silver, tin, barium, and lead ions from a feed stream containing 1 ppb of the metal ion selected from lithium, boron, sodium, magnesium, aluminum, potassium, calcium, titanium, vanadium, chromium, manganese, iron, nickel, copper, zinc, molybdenum, silver, tin, barium, and lead ions.

[0067]

[0076] In a second aspect, the present disclosure provides an assembly of the first aspect, wherein the assembly exhibits greater than 90% overall removal efficiency for all metal ions selected from lithium, boron, sodium, magnesium, aluminum, potassium, calcium, titanium, vanadium, chromium, manganese, iron, nickel, copper, zinc, molybdenum, silver, tin, barium, and lead ions.

[0068]

[0077] In a third aspect, the present disclosure provides an assembly of the first or second aspect, wherein the metal ions are selected from iron, nickel, chromium, copper, and aluminum Al ions.

[0069]

[0078] In a fourth aspect, the present disclosure provides an assembly of the first or second aspect, wherein the metal ions are selected from manganese ions, magnesium ions, and zinc ions.

[0070]

[0079] In a fifth aspect, the present disclosure provides the assembly of the first, second, or third aspect, wherein the metal ions are selected from iron ions, nickel ions, and chromium ions.

[0071]

[0080] In a sixth aspect, the present disclosure provides the assembly of the first, second or fourth aspect, wherein the metal ion is a manganese ion.

[0072]

[0081] In a seventh aspect, the present disclosure provides the assembly of the first, second or fourth aspect, wherein the metal ion is a magnesium ion.

[0073]

[0082] In an eighth aspect, the present disclosure provides the assembly of the first, second, or third aspect, wherein the metal ion is a zinc ion.

[0074]

[0083] In a ninth aspect, the present disclosure provides an assembly of any of the preceding aspects, wherein the monomer having a positive charge in the organic liquid is a quaternary ammonium compound having at least one carbon-carbon double bond.

[0075]

[0084] In a tenth aspect, the present disclosure provides the assembly of the ninth aspect, wherein the quaternary ammonium compound is selected from diallyldimethylammonium chloride, diallyldimethylammonium bromide, vinylbenzyltrimethylammonium chloride, and vinylbenzyltrimethylammonium bromide.

[0076]

[0085] In an eleventh aspect, the present disclosure provides an assembly of any of the preceding aspects, wherein the crosslinker is selected from methylene bis(acrylamide), tetraethylene glycol diacrylate, tetraethylene glycol dimethacrylate, divinyl sulfone, divinyl benzene, 1,3,5-triallyl-1,3,5-triazine-2,4,6(1H,3H,5H)-trione 98%, ethylene glycol divinyl ether, divinyl polyethylene glycol, and triallylamine.

[0077]

[0086] In a twelfth aspect, the present disclosure provides an assembly of any of the previous aspects, wherein the feed stream comprises a PGME / PGMEA solution (70:30 by volume), PGMEA, n-butyl acetate, or cyclohexanone.

[0078]

[0087] In a thirteenth aspect, the present disclosure provides a filter device comprising the assembly of any of the preceding aspects.

[0079]

[0088] In a fourteenth aspect, the present disclosure provides a method for producing a method for treating a cancer cell comprising: a. a porous membrane comprising poly(tetrafluoroethylene), the membrane having a coating thereon, the coating being prepared from the polymerization of at least one monomer and at least one crosslinking agent, the monomer forming a positively charged porous membrane in an organic liquid; b. A porous membrane having a coating thereon, the coating comprising poly(tetrafluoroethylene), the coating being prepared from the polymerization of at least one monomer and at least one crosslinking agent, the monomer being negatively charged in an organic liquid; a plurality of membranes comprising The filter device produces less than 0.080 ppb of at least one metal ion selected from sodium, magnesium, aluminum, potassium, calcium, iron, and zinc ions when immersed in a PGME / PGMEA solution (70:30 by volume) for 8 hours.

[0080]

[0089] In a fifteenth aspect, the present disclosure provides a filter device of the fourteenth aspect, wherein the positively charged monomer is a quaternary ammonium compound having at least one carbon-carbon double bond.

[0081]

[0090] In a sixteenth aspect, the present disclosure provides a filter device of the fifteenth aspect, wherein the quaternary ammonium compound is selected from diallyldimethylammonium chloride, diallyldimethylammonium bromide, vinylbenzyltrimethylammonium chloride, and vinylbenzyltrimethylammonium bromide.

[0082]

[0091] In a seventeenth aspect, the present disclosure provides a filter device of any of the fourteenth to sixteenth aspects, wherein the cross-linking agent is selected from methylene bis(acrylamide), tetraethylene glycol diacrylate, tetraethylene glycol dimethacrylate, divinyl sulfone, divinyl benzene, 1,3,5-triallyl-1,3,5-triazine-2,4,6(1H,3H,5H)-trione 98%, ethylene glycol divinyl ether, divinyl polyethylene glycol, and triallylamine.

[0083]

[0092] In an eighteenth aspect, the present disclosure provides a filter device of any of the fourteenth to seventeenth aspects, wherein the device produces less than 0.080 ppb of metal ions of each of sodium, magnesium, aluminum, potassium, calcium, iron, and zinc ions.

[0084]

[0093] In a nineteenth aspect, the present disclosure provides a porous membrane comprising poly(tetrafluoroethylene), the membrane having a coating, the coating being prepared from polymerization of at least one monomer and at least one crosslinker, the monomer having a positive charge in an organic liquid, the monomer being a quaternary ammonium compound having at least one carbon-carbon double bond.

[0085]

[0094] In a twentieth aspect, the present disclosure provides the membrane of the nineteenth aspect, wherein the quaternary ammonium compound is selected from diallyldimethylammonium chloride, diallyldimethylammonium bromide, vinylbenzyltrimethylammonium chloride, and vinylbenzyltrimethylammonium chloride, and vinylbenzyltrimethylammonium bromide.

[0086]

[0095] In a twenty-first aspect, the present disclosure provides the membrane of the nineteenth or twentieth aspect, wherein the at least one monomer further comprises a monomer that has a negative charge in the organic liquid.

[0087]

[0096] In a twenty-second aspect, the present disclosure provides a membrane of any of the nineteenth to twenty-first aspects, wherein the monomer having a negative charge in an organic liquid is selected from 2-ethylacrylic acid, acrylic acid, 2-carboxyethyl acrylate, 3-sulfopropyl acrylate potassium salt, 2-propylacrylic acid, 2-(trifluoromethyl)acrylic acid, methacrylic acid, 2-methyl-2-propene-1-sulfonic acid sodium salt, mono-2-(methacryloyloxy)ethyl maleate, 3-sulfopropyl methacrylate potassium salt, 2-acrylamido-2-methyl-1-propanesulfonic acid, 3-methacrylamidophenylboronic acid, vinylsulfonic acid, acrylamidomethylpropanesulfonic acid, and vinylphosphonic acid.

[0088]

[0097] In a twenty-third aspect, the present disclosure provides the membrane of the twenty-second aspect, wherein the monomer having a negative charge in the organic liquid is acrylamidomethylpropanesulfonic acid.

[0089]

[0098] In a twenty-fourth aspect, the present disclosure provides a filter device including the membrane of any of the nineteenth to twenty-third aspects.

[0090]

[0099] In a twenty-fifth aspect, the present disclosure provides a method for removing metal contaminants from an organic liquid, the method comprising passing the liquid through (i) a membrane assembly of any one of the first to twelfth aspects, (ii) a filter device of any one of the thirteenth to eighteenth aspects, or (iii) a membrane of any one of the nineteenth to twenty-third aspects.

[0091]

[0100] Although several exemplary embodiments of the present disclosure have been described above, those skilled in the art will readily appreciate that still other embodiments may be made and used within the scope of the claims appended hereto. Numerous advantages of the disclosure covered in this document have been set forth in the foregoing description. It will be understood, however, that this disclosure is, in many respects, merely illustrative. The scope of the disclosure is, of course, defined in the language in which the appended claims are expressed.

Claims

1. a. a porous membrane comprising poly(tetrafluoroethylene), the membrane having a coating thereon, the coating being prepared from the polymerization of at least one monomer and at least one crosslinking agent, the monomer having a positive charge in an organic liquid; b. a porous membrane comprising poly(tetrafluoroethylene), the membrane having a coating thereon, the coating being prepared from the polymerization of at least one monomer and at least one crosslinking agent, the monomer having a negative charge in an organic liquid; Including, 1. A membrane assembly exhibiting greater than 90% total removal efficiency of one or more metal ions selected from lithium, boron, sodium, magnesium, aluminum, potassium, calcium, titanium, vanadium, chromium, manganese, iron, nickel, copper, zinc, molybdenum, silver, tin, barium, and lead ions from a feed stream containing 1 ppb of the metal ion selected from lithium, boron, sodium, magnesium, aluminum, potassium, calcium, titanium, vanadium, chromium, manganese, iron, nickel, copper, zinc, molybdenum, silver, tin, barium, and lead ions.

2. 10. The assembly of claim 1, exhibiting greater than 90% overall removal efficiency for all metal ions selected from lithium, boron, sodium, magnesium, aluminum, potassium, calcium, titanium, vanadium, chromium, manganese, iron, nickel, copper, zinc, molybdenum, silver, tin, barium, and lead ions.

3. 3. The assembly according to claim 1 or 2, wherein the metal ions are selected from iron ions, nickel ions, chromium ions, copper ions and aluminium Al ions.

4. 3. The assembly according to claim 1 or 2, wherein the metal ions are selected from manganese ions, magnesium ions, and zinc ions.

5. 3. The assembly according to claim 1 or 2, wherein the metal ions are selected from iron ions, nickel ions and chromium ions.

6. 6. The assembly according to claim 1, wherein the monomer having a positive charge in the organic liquid is a quaternary ammonium compound having at least one carbon-carbon double bond.

7. 7. The assembly of claim 6, wherein the quaternary ammonium compound is selected from diallyldimethylammonium chloride, diallyldimethylammonium bromide, vinylbenzyltrimethylammonium chloride, and vinylbenzyltrimethylammonium bromide.

8. 8. The assembly of claim 1, wherein the crosslinking agent is selected from methylene bis(acrylamide), tetraethylene glycol diacrylate, tetraethylene glycol dimethacrylate, divinyl sulfone, divinyl benzene, 1,3,5-triallyl-1,3,5-triazine-2,4,6(1H,3H,5H)-trione 98%, ethylene glycol divinyl ether, divinyl polyethylene glycol, and triallylamine.

9. 9. The assembly of any one of claims 1 to 8, wherein the feed stream comprises a PGME / PGMEA solution (70:30 by volume), PGMEA, n-butyl acetate, or cyclohexanone.

10. A filter device comprising an assembly according to any one of claims 1 to 9.

11. 1. A filter device comprising a plurality of membranes, a. a porous membrane comprising poly(tetrafluoroethylene), the membrane having a coating thereon, the coating being prepared from the polymerization of at least one monomer and at least one crosslinking agent, the monomer having a positive charge in an organic liquid; b. a porous membrane comprising poly(tetrafluoroethylene), the membrane having a coating thereon, the coating being prepared from the polymerization of at least one monomer and at least one crosslinking agent, the monomer having a negative charge in an organic liquid; Including, A filter device that produces less than 0.080 ppb of at least one metal ion selected from sodium, magnesium, aluminum, potassium, calcium, iron, and zinc ions when immersed in a PGME / PGMEA solution (70:30 by volume) for 8 hours.

12. 12. The filter device of claim 11, wherein the positively charged monomer is a quaternary ammonium compound having at least one carbon-carbon double bond.

13. 13. The filter device of claim 12, wherein the quaternary ammonium compound is selected from diallyl dimethyl ammonium chloride, diallyl dimethyl ammonium bromide, vinyl benzyl trimethyl ammonium chloride, and vinyl benzyl trimethyl ammonium bromide.

14. 14. The filter device of any one of claims 11 to 13, wherein the cross-linking agent is selected from methylene bis(acrylamide), tetraethylene glycol diacrylate, tetraethylene glycol dimethacrylate, divinyl sulfone, divinyl benzene, 1,3,5-triallyl-1,3,5-triazine-2,4,6(1H,3H,5H)-trione 98%, ethylene glycol divinyl ether, divinyl polyethylene glycol, and triallyl amine.

15. 15. The filter device of any one of claims 11 to 14, producing less than 0.080 ppb of metal ions from each of sodium, magnesium, aluminum, potassium, calcium, iron, and zinc ions.

16. 1. A porous membrane comprising poly(tetrafluoroethylene), the membrane having a coating; The coating is prepared from the polymerization of at least one monomer and at least one crosslinker; The monomer has a positive charge in the organic liquid; The monomer is a quaternary ammonium compound having at least one carbon-carbon double bond. Porous membrane.

17. 17. The membrane of claim 16, wherein the quaternary ammonium compound is selected from diallyldimethylammonium chloride, diallyldimethylammonium bromide, vinylbenzyltrimethylammonium chloride, vinylbenzyltrimethylammonium chloride, and vinylbenzyltrimethylammonium bromide.

18. 20. The membrane of claim 17, wherein the at least one monomer further comprises a monomer that has a negative charge in the organic liquid.

19. 19. The membrane of any one of claims 16 to 18, wherein the monomer having a negative charge in the organic liquid is selected from 2-ethylacrylic acid, acrylic acid, 2-carboxyethyl acrylate, 3-sulfopropyl acrylate potassium salt, 2-propylacrylic acid, 2-(trifluoromethyl)acrylic acid, methacrylic acid, 2-methyl-2-propene-1-sulfonic acid sodium salt, mono-2-(methacryloyloxy)ethyl maleate, 3-sulfopropyl methacrylate potassium salt, 2-acrylamido-2-methyl-1-propanesulfonic acid, 3-methacrylamidophenylboronic acid, vinylsulfonic acid, acrylamidomethylpropanesulfonic acid, and vinylphosphonic acid.

20. 20. The membrane of claim 19, wherein the monomer having a negative charge in the organic liquid is acrylamidomethylpropanesulfonic acid.

21. A filter device comprising a membrane according to any one of claims 16 to 20.

22. 23. A method for removing metal contaminants from an organic liquid, comprising passing the liquid through (i) a membrane assembly according to any one of claims 1 to 9, (ii) a filter device according to any one of claims 10 to 15 and 21, or (iii) a membrane according to any one of claims 16 to 20.

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