Including liquid purification membranes containing carbon materials and their formation methods

Abstract

This application relates to liquid purification membranes comprising carbon-containing materials and methods for forming the same. A porous polymeric filter membrane is provided, the membrane comprising a polymer in which at least one carbon-containing material is mixed. The membrane is capable of removing trace amounts of various impurities from liquid compositions, including metal ions, acids, alkalis, and organic contaminants.

Description

Technical Field

[0001] This disclosure generally relates to the field of liquid purification using membrane technology. Background Technology

[0002] Filter products are essential tools in modern industry for removing unwanted materials from applicable fluids. Applicable fluids treated using filters include water, liquid industrial solvents and process fluids, industrial gases used in manufacturing or processing (e.g., semiconductor manufacturing), and liquids with medical or pharmaceutical applications. Undesirable materials removed from the fluid include impurities and contaminants such as particles, microorganisms, and dissolved chemicals. Specific examples of filter applications include their use with liquid materials in the manufacture of semiconductors and microelectronic devices.

[0003] The field of microelectronic device processing requires steady improvements in processing materials and methods to maintain parallel, stable improvements in microelectronic device performance (e.g., speed and reliability). Opportunities for improving microelectronic device manufacturing exist in all aspects of the manufacturing process, including methods and systems for filtering liquid materials.

[0004] In microelectronic device processing, a wide range of different types of liquid materials are used as process solvents, cleaning agents, and other processing solutions. Many (if not most) of these materials require extremely high levels of purity. For example, the liquid materials (e.g., solvents) used in the photolithography process of microelectronic devices must have extremely high purity. Specific examples of liquids used in microelectronic device processing include those used for spin-on glass (SOG) technology, for back-side anti-reflective coating (BARC) methods, and for photolithography process solutions. Summary of the Invention

[0005] In summary, this disclosure relates to membranes capable of removing impurities, such as alcohols and ammonium hydroxide (i.e., ammonia), from liquid compositions. The membranes are prepared by dispersing a carbon-containing material, such as activated carbon, within a polymer and preparing a filter membrane therefrom. The filter membranes of this disclosure are capable of removing trace amounts of certain amines and metal cations from such solutions. In one particular embodiment, this disclosure provides a membrane comprising a polymer doped with a carbon-containing material of greater than zero and less than about 80% by weight. The membrane is capable of providing liquid solutions of alcohols, such as C1-C4 alkanols, and ammonium hydroxide in extremely high purity. Attached Figure Description

[0006] Figure 1 This is an example of a filter component disclosed herein.

[0007] Figure 2 A graph showing particle retention rate (%) relative to particle loading (per layer %). Detailed Implementation

[0008] Unless otherwise expressly stated, the singular forms “a / an” and “the” as used in this specification and the appended claims include the plural form. Unless otherwise expressly stated, the term “or” as used in this specification and the appended claims is generally used in its sense to include “and / or”.

[0009] The term "about" generally refers to a range of numbers that are considered equivalent to the stated value (e.g., having the same function or result). In many cases, the term "about" may include numbers rounded to the nearest significant figure.

[0010] Numerical ranges expressed using endpoints include all numbers that fall into the range (e.g., 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, and 5).

[0011] To perform the filtration function, a filter may include a filter membrane responsible for removing unwanted materials from the fluid passing through it. Depending on the requirements, the filter membrane may be in the form of a flat sheet, which can be wound (e.g., spiral), flat, pleated, or disc-shaped. Alternatively, the filter membrane may be in the form of hollow fibers. The filter membrane may be housed within a housing or otherwise supported such that the fluid to be filtered enters through the filter inlet and needs to pass through the filter membrane before passing through the filter outlet.

[0012] Filter membranes can be composed of porous structures having an average pore size that can be selected based on the use of the filter, i.e., the type of filtration performed by the filter. Typical pore sizes are in the micrometer or submicrometer range, for example, from about 0.001 micrometers to about 10 μm. Membranes with an average pore size of about 0.001 to about 0.05 micrometers are sometimes classified as ultrafiltration membranes. Membranes with pore sizes between about 0.05 and 10 μm are sometimes referred to as microporous membranes.

[0013] Filter membranes, or simply “membranes” as used herein, with pore sizes in the micrometer or submicrometer range, can effectively remove unwanted material (i.e., impurities) from a fluid flow via a sieving mechanism, a non-sieving mechanism, or both. A sieving mechanism is a filtration method in which particles are removed from the liquid flow by mechanical retention at the surface of the filter membrane. This mechanically interferes with particle movement and retains particles within the filter, thereby mechanically preventing particles from flowing through the filter. Typically, the particles can be larger than the filter pores. A “non-sieving” filtration mechanism is a filtration method in which the filter membrane retains suspended particles or dissolved material contained in the fluid flow through the membrane in a partially mechanical manner. This method includes, for example, an electrostatic mechanism by which particles or dissolved impurities are electrostatically attracted to and retained at the filter surface and removed from the fluid flow; the particles may be soluble or may be solids with a particle size smaller than the pore size of the filter medium.

[0014] Therefore, in a first aspect, this disclosure provides a membrane comprising a polymer doped with a carbon-containing material of greater than zero and less than about 80% by weight, wherein the membrane (a) exhibits a bubble point of about 2 psi to about 200 psi when measured using ethoxy-nonafluorobutane HFE 7200 at a temperature of about 22°C, (b) has an isopropanol flow time of about 20 seconds / 500 ml to about 10,000 seconds / 500 ml when measured at 14.2 psi, and (c) has a G25 particle retention rate of about 25% to about 100%.

[0015] The filter including the membrane can take any desired form suitable for the filtration application. The material forming the filter can be a structural component of the filter itself and provide the desired architecture for the filter. The filter membrane can be porous and can be any desired shape or configuration. The filter membrane itself can be a single article or can be represented by multiple separate articles, such as particles (e.g., resin beads). The membrane is formed from polymeric materials, mixtures of different polymeric materials, or polymeric and non-polymeric materials. Polymeric materials that can be used to form the membranes of this disclosure include hydrophobic or hydrophilic polymers. Suitable polymers include polyamides, polyimides, polyolefins, polyethersulfones, polyacrylates, polyesters, cellulose, cellulose esters, polycarbonates, poly(phenylene ether), poly(styrene), or combinations thereof. For example, the polymeric material of the membrane can be a hydrophobic polymer selected from: ultra-high molecular weight polyethylene; polyethylene; polypropylene; polymethylpentene; polybutene; polyisobutylene; copolymers of two or more of ethylene, propylene, and butene; halogenated polymers; or combinations thereof.

[0016] In certain embodiments, the filter membrane material includes ultra-high molecular weight polyethylene (UPE). UPE filter materials, such as those used in UPE membranes, typically have a molecular weight (weight-average molecular weight) greater than about 1 × 10⁻⁶. 6 Dalton (Da), for example, in about 1×10 6 -9×10 6 Da or 1.5×10 6 -9×10 6 Resin formation within the range of Da. Crosslinking between polyolefin polymers such as polyethylene can be promoted by the use of heat or crosslinking chemicals such as peroxides (e.g., dicumyl peroxide or di-tert-butyl peroxide), silanes (e.g., trimethoxyvinylsilane), or azo compounds (e.g., 2,2'-azobis(2-acetoxypropane)).

[0017] Exemplary halogenated polymers include polytetrafluoroethylene (PTFE), polychlorotrifluoroethylene (PCTFE), fluorinated ethylene polymer (FEP), polyhexafluoropropylene, and polyvinylidene fluoride (PVDF).

[0018] In one embodiment, the porous membrane is asymmetric. In one example of an asymmetric membrane, the pore size on one facet and region of the membrane is larger than the pore size on the opposite facet and region. In another example, an asymmetric structure may exist where the pore size on opposite faces (and regions) of the membrane is larger, while the central region of the membrane has a smaller pore size than either facet (e.g., an hourglass pore size distribution). In other embodiments, the microporous membrane may have a substantially symmetrical pore structure over its thickness (approximately the same pore size over the membrane thickness).

[0019] In some embodiments, the filter membrane may be a composite membrane comprising two or more porous polymeric membranes, which may be made of the same or different materials and / or have the same or different structures. As described herein, at least one porous polymeric membrane of the composite membrane contains a carbon-containing material. For example, the filter membrane may include a first porous polymeric membrane comprising the membrane of this disclosure, having a carbon-containing material, and a second filter material that does not include the membrane of this disclosure, or differs from the membrane of this disclosure in some respects, such as containing different polymers, different types or amounts of carbon-containing material, having different pore structures, etc. Additional filter material layers are also possible, incorporating various combinations of polymers with or without carbon-containing material, wherein at least one layer is the membrane of this disclosure. Thus, the composite membrane can be considered a multilayer membrane having a first filter layer in contact with a second filter layer. As a specific example, the composite membrane may be a co-cast or co-folded membrane of a first polymer and a second polymer, wherein one or both of these polymer layers contain a carbon-containing material.

[0020] Therefore, in a particular embodiment, this disclosure provides a composite filter comprising:

[0021] A first filter material and a second filter material, wherein the outer surface of the first filter material is in contact with the outer surface of the second filter material.

[0022] The first filter material comprises a porous polymer membrane, the porous polymer membrane comprising a polymer incorporating a carbon-containing material of greater than zero and less than about 80% by weight.

[0023] Furthermore, the second filter material is different from the first filter material.

[0024] The outer surface of the first filter material can be the output-facing surface (in the direction of flow through the composite membrane), and the outer surface of the second filter material can be the input-facing surface, and vice versa.

[0025] As used herein, a “porous polymeric membrane” is a polymeric solid containing pores (e.g., micropores), which are interconnected channels extending from one surface of the membrane to the opposite surface. These channels typically provide a tortuous path or channel through which the liquid to be filtered must pass. When a particle-containing fluid passes through the membrane, any particles contained in the liquid larger than the pore size are prevented from entering the microporous membrane or are trapped within the pores of the microporous membrane (i.e., removed by a sieving filtration mechanism). Particles smaller than the pore size are also trapped or absorbed onto the pore structure and can be removed, for example, by a non-sieving filtration mechanism.

[0026] The membrane disclosed herein comprises a carbon-containing material distributed throughout the membrane structure. The carbon-containing material may include, for example, activated carbon, carbon black, graphene, and carbon nanotubes. For example, activated carbon is an adsorbent that can be derived from any carbon-containing precursor capable of being converted into activated carbon. Examples of such carbon-containing precursors include wood, corn cobs, kelp, coffee beans, rice husks, fruit pits, peat, lignite, coconut shells, petroleum and / or coal tar pitch, coke, carbon black, phenolic resins, polyvinyl chloride, etc. The morphology of the carbon-containing material incorporating the polymer with the porous polymer membrane is not particularly critical and may be selected from powders, particles, fibers, flakes, etc. In one embodiment, the carbon-containing material is in powder, particle, or extruded form.

[0027] For example, carbon-containing materials can be activated carbon, which is a solid microporous material with a high surface area, mainly composed of elemental carbon, and in the case of lignin-derived carbon-containing materials, further containing trace amounts of other trace elements originally found in the carbon-containing precursor materials that form activated carbon. Furthermore, activated carbon can be derived from fully synthetic (i.e., petrochemical) sources, such as polystyrene, poly(dichloroethylene), or poly(dichloroethylene)-methyl acrylate copolymers, provided that in any case, the final activated carbon surface has the necessary porosity to be effective in the methods of this disclosure as taught herein. In this case, activated carbon is a microcrystalline, non-graphite form of carbon processed to increase its porosity. The surface area of ​​activated carbon depends on its pore volume. The surface area per unit volume decreases with increasing individual pore size, thus maximizing the surface area by increasing the number of very small pores and / or limiting the number of large pores. Pore size is defined by the International Union of Pure and Applied Chemistry as micropores (pore width < 2 nm), mesopores (pore width 2–50 nm), and macropores (pore width > 50 nm). Furthermore, in this type of activated carbon, micropores and mesopores contribute to the adsorption capacity of the activated carbon, while macropores actually reduce the density and may be detrimental to the adsorption efficiency of the activated carbon (based on carbon volume).

[0028] In one embodiment of this disclosure, the carbon-containing material will be in powder or particulate form. Such carbon-containing materials can be purchased in this desired form or can be milled or jet-milled to obtain the desired particle size before being added to the polymeric material used to manufacture the membrane. In some embodiments, porous polymeric membranes comprising polymers as disclosed herein will be incorporated with greater than zero to about 80%, for example, about 1 to about 60 wt%, 2 wt% to about 40 wt%, or 5 wt% to about 20 wt% of carbon-containing material. To maintain the structural integrity or physical form of the membrane, a lower content of carbon-containing material, such as activated carbon, may be preferred.

[0029] Furthermore, the carbon-containing material and / or polymer of the porous polymeric membrane will preferably have less than about 65 μg of extractable organic compounds and / or metal ions. This level of purity of the components can be achieved by cleaning with a suitable solvent prior to membrane formation using techniques known to those skilled in the art. Lower impurity content, for example, less than 50 μg, would be even more preferred.

[0030] In some embodiments, the porous polymeric membrane is in the form of a sheet or hollow fiber. In some embodiments, the sheet or hollow fiber can have any useful thickness, for example, in the range of about 35 μm to about 400 μm, about 80 μm to about 350 μm, or about 120 μm to about 310 μm, or about 160 μm to 270 μm, or any range and subrange thereof. The porous polymeric membrane sheet can be used as a flat sheet membrane or can be wrinkled to form a pleated membrane.

[0031] In a particular embodiment, the carbon-containing material is activated carbon. Activation of the carbon-containing material can be performed by known methods. For example, the carbon-containing material can be activated with oxidizable chemicals such as zinc chloride, phosphoric acid, sulfuric acid, calcium chloride, sodium hydroxide, potassium dichromate, potassium permanganate, etc. (chemical activation); or with steam, propane gas, exhaust gas from the combustion of a mixture of CO2 and H2O, carbon dioxide gas, etc. (gas activation). See, for example, U.S. Patent No. 6,589,904, which is incorporated herein by reference in its entirety. Alternatively, commercially available activated carbon can be used, such as activated carbon products from Calgon Carbon, which are available as powder or granules. In one embodiment, after grinding, the median average particle size of the activated carbon is about 30 μm to about 60 μm, or about 45 μm. In another embodiment, the activated carbon will have a particle size greater than or equal to about 800 μm. 2 / g of surface area.

[0032] The porous polymeric membranes disclosed herein can be prepared by combining a polymeric material with a carbon-containing material to load and disperse the desired carbon-containing material into the polymeric component. Depending on the desired polymer, a dissolving or dispersing solvent can also be used, with or without heating. For example, polymers such as polysulfone can be dissolved in a suitable solvent, such as N-methylpyrrolidone (NMP), to which a non-solvent, such as isopropanol, is added to form a coating or varnish. Activated carbon can be added to this mixture, and the resulting mixture is homogenized by vigorous stirring. The mixture can then be applied to a glass plate and immersed in a non-solvent. In other words, dip casting can be used to form porous polymeric membranes containing incorporated carbon-containing materials. Alternatively, in the case of polymers with different solubility characteristics, such as high molecular weight polyethylene, such polymers can be dispersed together with carbon-containing materials in, for example, dioctyl phthalate (DOP) and mineral oil, thus producing a slurry. The slurry can then be extruded into sheets, treated with various liquids to remove the mineral oil and dioctyl phthalate, and dried to form a porous polymeric membrane in sheet form. In other words, once the carbon-containing material has been dispersed within the polymer matrix, the membrane disclosed herein can be prepared using known temperature-induced phase separation (TIPS) or solvent-induced phase separation (SIPS) processes used in forming polymer sheets containing thermoplastic polymers.

[0033] Therefore, in another aspect, this disclosure provides a method for preparing a porous polymeric membrane in sheet form for filtering liquids containing organic and metal ion impurities, wherein the porous polymeric membrane comprises a polymer in which a carbon-containing material, such as activated carbon, is dispersed, the method comprising the following steps:

[0034] Combining a carbon-containing material with a flowable form of a polymer, wherein the polymer has been (i) blended with an effective amount of at least one solvent and / or dispersant to provide a flowable form; and / or (ii) heated to a temperature sufficient to provide a flowable form;

[0035] Physically dispersing carbon-containing materials into a polymer, thereby providing a polymer composition in which carbon-containing materials are dispersed; and

[0036] When present, remove the solvent or dispersant from the polymer composition, and / or cool the polymer composition during casting or extrusion into sheets;

[0037] The porous polymer membrane is capable of removing up to about 60% to about 100% of amine contaminants and about 75% to about 95% of metal ion contaminants from liquids.

[0038] In one embodiment of this method, the polymer is selected from polyamide, polyimide, polyolefin, polyethersulfone, polyacrylate, polyester, cellulose, cellulose ester, polycarbonate, poly(phenylene ether), polystyrene, or combinations thereof. In another embodiment, the polymer is selected from ultra-high molecular weight polyethylene; polyethylene; polypropylene; polymethylpentene; polybutene; polyisobutylene; copolymers of two or more of ethylene, propylene, and butene; polytetrafluoroethylene; polychlorotrifluoroethylene; fluorinated ethylene polymers; polyhexafluoropropylene; polyvinylidene fluoride; polyamide; polyimide; polysulfone; polyethersulfone; polyarylsulfone; polyacrylate; polyester; nylon; cellulose; cellulose ester; polycarbonate; polysulfone; poly(phenylene ether); poly(styrene); or combinations thereof.

[0039] Referring to porous polymeric membranes as described herein, such membranes may be characterized by physical features, including pore size, bubble point, and porosity. In this regard, porous polymeric membranes may have any pore size that allows the membrane to function effectively as a membrane, such as those described herein, including pore sizes (average pore size) sometimes considered as microporous or ultrafiltration membranes. Examples of useful porous polymeric membranes have an average pore size in the range of about 0.001 μm to about 1 or 2 μm, for example, 0.01 to 0.8 μm, where the pore size is selected based on one or more factors, including: the particle size or type of impurities to be removed, pressure and pressure drop requirements, and the viscosity requirements of the liquid being processed by the filter. The average pore size of ultrafiltration membranes can range from 0.001 μm to about 0.05 μm. Pore size is often reported as the average pore size of porous materials and can be measured using known techniques, such as mercury porosimetry (MP), scanning electron microscopy (SEM), liquid displacement microscopy (LLDP), or atomic force microscopy (AFM).

[0040] Bubble point is also a known characteristic of porous membranes. According to the bubble point test method, a sample of a porous polymer filter membrane is immersed in and wetted with a liquid having a known surface tension, and air pressure is applied to one side of the sample. The air pressure is gradually increased. The minimum pressure required for gas to flow through the sample is called the bubble point. As a specific method for determining the bubble point of porous polymeric materials, a sample of the porous material is immersed in and wetted with ethoxy-nonafluorobutane HFE 7200 (available from 3M) at a temperature of 20-25°C (e.g., 22°C). Air pressure is applied to one side of the sample using compressed air, and the air pressure is gradually increased. The minimum pressure required for gas to flow through the sample is called the bubble point. All bubble point values ​​provided herein were measured using this procedure. Examples of useful or preferred bubble point values ​​of porous polymeric filter membranes according to this specification, measured using the procedures described above, may be in the following ranges: about 2 to about 200 psi, about 2 to about 150 psi, about 2 to about 100 psi, about 10 to about 200 psi, about 10 to about 150 psi, about 10 to about 100 psi, about 10 to about 40 psi, about 20 to about 200 psi, about 20 to about 150 psi, about 20 to about 100 psi, about 40 to about 200 psi, about 40 to about 150 psi, about 40 to about 100 psi, about 60 to about 200 psi, about 60 to about 150 psi, about 60 to about 100 psi, about 80 to about 200 psi, about 80 to about 150 psi, about 100 to about 200 psi, about 100 to about 150 psi, about 150 to about 200 psi, or any and all ranges between them. The porous polymeric membranes described herein can have any porosity to make them effective as described herein. Example porous polymeric membranes can have relatively high porosities, such as at least 60%, 70%, or 80%. As used herein and in the field of porous materials, the “porosity” (sometimes also referred to as void fraction) of a porous material is a measure of the percentage of void (i.e., “empty”) space in the total volume of the material, and is calculated as the fraction of the void volume of the material to the total volume of the material. A material with 0% porosity is entirely solid.

[0041] The porous polymeric filter membrane disclosed herein is applicable to any type of industrial or life science process that requires high-purity liquid materials as input. Non-limiting examples of such processes include processes for fabricating microelectronic or semiconductor devices, a specific example being methods for filtering liquid processing materials (e.g., solvents or solvent-containing liquids) used in semiconductor lithography. Examples of contaminants present in process liquids or solvents used to fabricate microelectronic or semiconductor devices may include metal ions dissolved in the liquid, solid particles suspended in the liquid, and gel or coagulated materials present in the liquid (e.g., generated during lithography).

[0042] As discussed above, porous polymeric membranes can be single-layered or multi-layered, and can be combined with another filter material to form a composite filter membrane. In either case, the filter membrane can be used to remove dissolved or suspended contaminants or impurities from a liquid by means of a sieving mechanism or a non-sieving mechanism, and preferably by a combination of non-sieving and sieving mechanisms, allowing the liquid to flow through the filter membrane.

[0043] Such porous polymer membranes have been found to be useful for removing metal ion contaminants as well as organic contaminants such as amines, to provide liquid compositions of extremely high purity. Exemplary liquid compositions are materials containing, for example, organic solvents such as alcohols and ketones, and dissolved ammonia, i.e., NH4OH. In this regard, reference to ammonia or simply "ammonia" is understood to mean an aqueous solution of NH4OH containing any concentration of ammonia. Therefore, in another aspect, this disclosure provides a purified liquid composition comprising one or more ketones or alcohols, wherein the purified composition contains no more than about 2000 ppb of organic amine impurities. In one embodiment, the organic amine impurity is selected from triethylamine, N,N-diisopropylamine, heptamine, and 3,3,5,5-tetramethylbenzidine. In another embodiment, the alcohol is a C1-C4 alcohol, such as isopropanol.

[0044] Furthermore, various metallic impurities can also be removed using the porous polymeric membranes described herein. In some embodiments, the resulting purified liquid composition contains metal ions, such as cations of magnesium, aluminum, titanium, vanadium, manganese, nickel, copper, zinc, molybdenum, silver, cadmium, tin, and lead, in total amounts not exceeding about 12 ppb.

[0045] In one particular embodiment, the purified liquid composition comprises not less than 99.99% by weight of isopropanol, the composition comprising a total of not more than about 2000 ppb of amines and a total of not more than about 12 ppb of metal ions. In another embodiment, the purified liquid composition comprises NH4OH, wherein the composition contains not more than about 2000 ppb of impurities selected from triethylamine, isopropylamine, heptamine, N,N-diisopropylethylamine and tetramethylbenzidine.

[0046] Therefore, the porous polymer membranes of this disclosure enable processes or methods for filtering or purifying various liquids and organic compositions. Accordingly, in another aspect, this disclosure provides a method for preparing a purified liquid composition comprising (a) one or more ketones or alcohols, or (b) ammonia. In one embodiment, the composition contains an impurity of not more than 2000 ppb, the impurity being selected from one or more of triethylamine, N,N-diisopropylamine, heptamine, N,N-diisopropylethylamine, and 3,3,5,5-tetramethylbenzidine. This purified composition can be obtained by a method comprising exposing the liquid composition to be purified to one or more of the porous polymer membranes of this disclosure, the liquid composition comprising (i) one or more ketones or alcohols or (ii) NH4OH, and at least one organic amine impurity selected from one or more of the following: triethylamine, N,N-diisopropylamine, heptamine, and N,N-diisopropylethylamine, and 3,3,5,5-tetramethylbenzidine. In one embodiment, the purified composition comprises not less than about 99.99% by weight of a ketone or alcohol (e.g., isopropanol), or ammonia. Exposure to the porous polymer membrane can be achieved by actively passing the liquid composition through the membrane or simply immersing the membrane in the liquid composition to be purified. In another embodiment, the purified composition contains a total of no more than 12 ppb of metal ions.

[0047] Therefore, the porous polymeric membranes described herein can be used to purify various types of liquid compositions, such as liquid chemicals (including solvents) used or useful in semiconductor or microelectronics manufacturing applications. For example, the liquid composition may contain liquid chemicals or a combination of liquid chemicals and one or more impurities, optionally further comprising various additional components, such as polymeric materials for photoresists. The porous polymeric membranes of this disclosure can effectively remove all or most impurities (i.e., unwanted substances) from liquid compositions. Examples of suitable liquid chemicals include, but are not limited to, methyl pentyl ketone, ethyl 3-ethoxypropionate, propylene glycol methyl ether (PGME), propylene glycol methyl ether acetate (PGMEA), propylene glycol monomethyl ether (PGME) and PGMEA (e.g., 7:3), methanol, ethyl acetate, ethyl lactate, and combinations thereof. Other examples include organic amines such as hydroxylamine, monoethanolamine (MEA), triethanolamine (TEA), morpholine, N-methyldiethanolamine (MDEA), N-monomethylethanolamine (MMEA), N-ethylaminoethoxyethanol, 2-(2-aminoethoxy)ethanol, tetraethylammonium hydroxide (TEAH), tetrabutylammonium hydroxide (TBAH), and combinations thereof. Other examples of liquid chemicals from which impurities can be removed by the porous polymeric membranes of this disclosure include n-butyl acetate (nBA), isopropanol (IPA), 2-ethoxyethyl acetate (2EEA), xylene, cyclohexanone, methyl isobutyl methanol (MIBC), methyl isobutyl ketone (MIBK), isoamyl acetate, and undecane. Other process liquids, such as deionized water, hydrogen peroxide, hydrochloric acid, sulfuric acid, and mixtures thereof, can also be purified using the porous polymeric membranes described herein. Therefore, using the disclosed membrane, impurities such as metal ions and / or organic impurities such as fluorinated organic compounds can be removed from liquid compositions such as acids, bases, peroxides, liquid chemicals (including those containing polymers) and mixtures thereof.

[0048] Therefore, the membrane of this disclosure is capable of purifying certain liquid compositions as described herein to provide an extremely pure composition having, after filtration, amounts of impurities such as amine / organic and metal ion contaminants close to the detection limit. Thus, in another aspect, this disclosure provides a purified liquid composition comprising:

[0049] a) One or more ketones or alcohols, or

[0050] b) Ammonia water,

[0051] The composition contains no more than 2000 ppb of one or more impurities selected from triethylamine, isopropylamine, heptamine, N,N-diisopropylethylamine, and tetramethylbenzidine.

[0052] A composition obtained by exposing a liquid composition requiring purification to one or more porous polymeric membranes as described herein, wherein the liquid composition comprises

[0053] i) one or more ketones or alcohols, or

[0054] ii) Ammonia water, and at least one amine impurity selected from one or more of triethylamine, isopropylamine, N,N-diisopropylamine, heptamine and 3,3,5,5-tetramethylbenzidine.

[0055] Retention rate test

[0056] "Particle retention" or "coverage" refers to the percentage of particles removed from a fluid flow by a membrane placed in the fluid path of the fluid flow. The particle retention determined according to the following procedure is referred to as the "G25 particle retention". The particle retention of a 47 mm membrane disc can be measured as follows: a sufficient amount of a feed aqueous solution of 0.1% Triton X-100 containing 8 ppm of polystyrene particles (purchased from Duke Scientific G25B) with a nominal diameter of approximately pH 5 is passed through the membrane at a constant flow rate of 7 mL / min to achieve 1% monolayer coverage, and the permeate is collected. Unless otherwise specified, the G25 particle retention is determined using a 1% monolayer. The concentration of polystyrene particles in the permeate can be used to calculate the absorption rate of the permeate. The particle retention is then calculated using the following equation:

[0057]

[0058] The number of particles (#) required to achieve 1% single-layer coverage can be calculated from the following equation:

[0059]

[0060] in:

[0061] a = Effective membrane surface area

[0062] d p =Particle diameter

[0063] n = % Single layer

[0064] As used herein, “nominal diameter” refers to the particle diameter as determined by photon correlation spectroscopy (PCS), laser diffraction, or optical microscopy. Typically, the calculated or nominal diameter is expressed as the diameter of a sphere having the same projected area as the projected image of the particle. PCS, laser diffraction, and optical microscopy techniques are well-known in their respective fields. See, for example, Jillavenkatesa, A. et al.; “Particle Size Characterization”; NIST Recommended Practice Guide; NIST Special Publication 960-1; January 2001.

[0065] In some embodiments, the G25 particle retention rate is in the following ranges: about 25% to about 100%, about 25% to about 99%, about 25% to about 97%, about 25% to about 95%, about 25% to about 90%, about 25% to about 85%, 50% to about 100%, about 50% to about 99%, about 50% to about 97%, about 50% to about 95%, about 50% to about 90%, about 50% to about 85%, about 70% to about 100%, about 70% to about 99%, about 70% to about 97%, about 70% to about 95%, about 70% to about 90%. About 70% to about 85%, 75% to about 100%, about 75% to about 99%, about 75% to about 97%, about 75% to about 95%, about 75% to about 90%, about 75% to about 85%, 80% to about 100%, about 80% to about 99%, about 80% to about 97%, about 80% to about 95%, about 80% to about 90%, about 80% to about 85%, 85% to about 100%, about 85% to about 99%, about 85% to about 97%, about 85% to about 95%, about 85% to about 90%, about or all ranges and subranges therein.

[0066] In some embodiments, the membrane disclosed herein has a G25 particle retention rate (i.e., at 1% monolayer) within any range disclosed above, and also has a G25 particle retention rate at 5% monolayer within the ranges of: about 60% to about 80%, about 60% to about 75%, about 60% to about 70%, about 65% to about 80%, about 65% to about 75%, about 70% to about 80%, or all ranges and subranges thereof.

[0067] The filter membranes described herein can have relatively low flow times, preferably in combination with relatively high bubble points, and good filtration performance (e.g., measured by particle retention, dye binding capacity, or both). Examples of useful or preferred isopropanol flow times are below about 20,000 seconds / 500 ml, for example below about 4,000 or 2,000 seconds / 500 ml.

[0068] The membrane flow time of isopropanol (IPA) reported in this article can be measured at 14.2 psi and 21 °C, when 500 ml of isopropanol (IPA) fluid passes through an effective surface area of ​​13.8 cm². 2 The required time for the membrane to be formed on the 47mm membrane disk is determined. In some embodiments, the flow time is within the following ranges: approximately 20 seconds / 500 ml to approximately 10,000 seconds / 500 ml, approximately 20 seconds / 500 ml to approximately 5,000 seconds / 500 ml, approximately 20 seconds / 500 ml to approximately 1,000 seconds / 500 ml, approximately 20 seconds / 500 ml to approximately 800 seconds / 500 ml, approximately 20 seconds / 500 ml to approximately 500 seconds / 500 ml, approximately 100 seconds / 500 ml to approximately 10,000 seconds / 500 ml, approximately 100 seconds / 500 ml to approximately 5,000 seconds / 500 ml, approximately 100 seconds / 500 ml to approximately 1,000 seconds / 500 ml, approximately 100 seconds / 500 ml to approximately 800 seconds / 500 ml, approximately 100 seconds / 500 ml to approximately 500 seconds / 500 ml, approximately 500 seconds / 500 ml to approximately 10,000 seconds / 500 ml. 00 seconds / 500 ml, approximately 500 seconds / 500 ml to approximately 5,000 seconds / 500 ml, approximately 500 seconds / 500 ml to approximately 1,000 seconds / 500 ml, approximately 500 seconds / 500 ml to approximately 800 seconds / 500 ml, approximately 845 seconds / 500 ml to approximately 10,000 seconds / 500 ml, approximately 845 seconds / 500 ml to approximately 5,000 seconds / 500 ml, approximately 84 5 seconds / 500 ml to about 1,665 seconds / 500 ml, about 845 seconds / 500 ml to about 1,000 seconds / 500 ml, about 1,000 seconds / 500 ml to about 10,000 seconds / 500 ml, about 1,000 seconds / 500 ml to about 5,000 seconds / 500 ml, about 20 seconds / 500 ml to about 2,500 seconds / 500 ml, or all ranges and subranges thereof.

[0069] In some embodiments, the membrane described herein may have a flow time approximately equal to or greater than that of the same filter membrane without carbon-containing material. In other words, the incorporation of carbon-containing material does not have a materially negative impact on the flow characteristics of the filter membrane, but still improves the filtration function of the filter membrane, especially the non-sieving filtration function of the membrane, for example, depending on the pore size, as measured by dye binding capacity, particle retention rate, or both.

[0070] The porous polymeric filter membranes described herein can be incorporated into larger filter structures, such as multilayer filter assemblies or cartridges for filtration systems. The filtration system places the filter membrane (e.g., as part of a multilayer filter assembly or as part of a cartridge) within a filter housing to expose the membrane to the flow path of the liquid composition, such that at least a portion of the liquid composition flow passes through the porous polymeric filter membrane comprising a carbon-containing material, thereby removing a quantity of impurities or contaminants from the liquid composition. The structure of the multilayer filter assembly or cartridge may include one or more of various additional materials and structures supporting the filter membrane within the filter assembly or cartridge to allow fluid to flow from the filter inlet through the membrane (including the filter layer) and through the filter outlet, thereby passing through the filter membrane as it passes through the filter. The filter membrane supported by the filter assembly or cartridge can be in any suitable shape, such as a pleated cylinder, a cylindrical gasket, one or more non-pleated (flat) cylindrical sheets, pleated sheets, etc.

[0071] A specific example of a filter structure comprising a porous polymeric membrane in the form of a pleated cylinder can be prepared to include any of the following components, which may be included in the filter construction but are not required: a rigid or semi-rigid core supporting the interior of the pleated cylindrical porous polymeric membrane; a rigid or semi-rigid cage supporting or surrounding the exterior of the pleated cylindrical coated membrane; optional end pieces or "discs" located at each of the two opposite ends of the pleated cylindrical coated membrane; and a filter housing including an inlet and an outlet. The filter housing may have any suitable and desired size, shape, and material, and is preferably made of a suitable polymeric material.

[0072] As an example, Figure 1 A filter assembly 30 is shown, which is a combination of a pleated cylindrical assembly 10 and end pieces 22, as well as other optional components. The cylindrical assembly 10 includes a pleated filter membrane 12 as described herein. The end piece 22 is attached (e.g., “canned”) to one end of the cylindrical filter assembly 10. The end piece 22 may preferably be made of a melt-processable polymeric material. A core (not shown) may be placed at an internal opening 24 of the pleated cylindrical assembly 10, and a cage (not shown) may be placed around the external periphery of the pleated cylindrical assembly 10. A second end piece (not shown) may be attached (“canned”) to a second end of the pleated cylindrical assembly 10. The resulting filter assembly 30, having two opposing canned ends and optional core and cage, can then be placed in a filter housing including an inlet and an outlet and configured such that all fluid entering the inlet must pass through the filter membrane 12 before leaving the filter at the outlet.

[0073] Example

[0074] Example 1: Preparation of a porous polymer membrane containing ultra-high molecular weight polyethylene (UPE) and activated carbon

[0075] A 15% (w / w) dispersion of UPE (ultra-high molecular weight polyethylene) in a mixture of DOP (dioctyl phthalate) and mineral oil was prepared at room temperature, with 5% (w / w) powdered activated carbon added to the mixture. The average particle size of the UPE polymer was approximately 120 nm. The mineral oil had a viscosity of 68 CP at 40 °C and a specific gravity of 0.86 at 25 °C. The three-component mixture with a viscous slurry consistency was fed into a Brabender twin-screw mixer / extruder with a pair of 42 mm slotted counter-rotating screws L / D-(7:1). A Zenith gear pump and a 5" wide die are also connected to the extruder for extruding the melt blend into sheet form. The temperature of each extrusion zone is set between 180°C and 260°C. The volumetric output of the melt blend from the extruder is 46 cc / min. The extruded film is quenched on rotating chrome-plated cooling rollers, with the temperature controlled at 90°C by circulating a thermostatic fluid through the rollers. The quenched film is wound up by an electric winder at approximately 6 ft / min and spun with highly porous, lightweight polypropylene. Interlaced nonwoven fabric material was used. To extract mineral oil from the quenched gel membrane, interlaced rollers were placed in a metal frame and clamped, and the frame was placed in a Baron-Blakslee degreasing agent containing hydrofluoroethane (HFE) for reflux extraction. The extraction time was between 12 and 24 hours. The membrane was then dried at room temperature to remove the extractant and further heat-set at 100°C for 5 minutes. During drying and heat setting, the membrane was constrained by the material itself. This helped prevent excessive shrinkage of the membrane.

[0076] This general procedure can also be used to prepare other levels of activated carbon, such as 20% or 50% (w / w). Using the above method, it was found that the separated porous polymeric UPE membranes containing 5%, 20%, and 50% (w / w) activated carbon had the IPA (isopropanol) flow times and bubble point values ​​shown in Table 1.

[0077] Table 1

[0078]

[0079]

[0080] Example 2: Preparation of porous polymeric membranes containing polysulfone and activated carbon

[0081] M at room temperature wA 12% (w / w) polyphenylene sulfone (PPSU) resin with a strength of 50,700 Da was dissolved in N-methyl-2-pyrrolidone (NMP). Isopropanol (IPA) was slowly added to this solution to form a coating (paint) solution. 5% to 10% (w / w) powdered activated carbon was added to the resulting mixture and dispersed in the mixture using a hand-held homogenizer for 5–10 minutes. The resulting coating mixture was then applied to a glass plate using a 7-mil knife, and the porous polysulfone membrane containing the incorporated activated carbon was separated by dip-casting into a non-solvent.

[0082] Example 3: Determination of the filtration retention rate of G25 beads on a porous UPE membrane containing activated carbon.

[0083] G25 particle retention was determined in the UPE membrane using the method described above (at pH 5). Ultra-high molecular weight polyethylene membranes containing activated carbon were prepared using the method described in Example 1. G25 particle retention was calculated for monolayers of 0.5%, 1%, 1.5%, 2%, 3%, 4%, and 5%. The porous UPE membrane containing activated carbon exhibited improved G25 bead retention compared to the porous UPE membrane without activated carbon. Bead retention increased at 5% and 20% activated carbon loadings compared to the porous UPE membrane without activated carbon. The results are depicted in Table 2 and plotted on [the graph / plotting table]. Figure 2 middle.

[0084] Table 2 -G25 particle retention rate

[0085] UPE containing 5% activated carbon UPE containing 20% ​​activated carbon UPE Comparison 0.5% single layer 88.9％ 95.2％ 82.2％ 1% single layer 83.4％ 90.6％ 74.8％ 1.5% single layer 79.9％ 86.6％ 73.7％ 2% single layer 76.8％ 83.5％ 67.3％ 3% single layer 72.9％ 80.3％ 31.7％ 4% single layer 70.0％ 76.9％ 23.8％ 5% single layer 69.2％ 74.5％ 12.3％

[0086] Example 4: Determination of organic matter removal in IPA using a porous UPE membrane containing activated carbon

[0087] The following example demonstrates the removal of organic impurities from isopropanol (IPA) using a UPE membrane containing activated carbon. A porous UPE membrane containing activated carbon was prepared using a method similar to that shown in Example 1, and then cut into 47 mm membrane samples. To determine the filtration efficiency for organic matter removal, the membrane samples were immersed in an IPA solution with added organic impurities (2 ppm for each contaminant). The removal efficiency was determined using GC-MS. The results are described in Table 3 for organic matter removal (%).

[0088] Table 3 - Static organic matter removal efficiency in isopropanol (IPA)

[0089]

[0090]

[0091] As shown, porous UPE membranes containing activated carbon exhibit efficient organic matter removal compared to the UPE control. Using a 50% carbon-modified membrane, 100% removal of amine-based impurities, such as tetramethylbenzidine (TMB) and heptamine, is achieved. UPE membranes containing non-activated carbon do not remove the same impurities. Similarly, large-chain hydrocarbons are also effectively removed (>95%) compared to UPE alone.

[0092] Example 5: Determination of organic matter removal in 29% ammonia using a porous UPE membrane containing activated carbon.

[0093] The following example demonstrates the removal of organic impurities from a 29% ammonia solution. A UPE membrane containing activated carbon was prepared using a method similar to that in Example 1, and membrane samples were cut into 47 mm pieces. To determine the removal efficiency of the filtered organic matter, the membrane samples were immersed in a 29% ammonia solution, incorporating organic impurities, and subjected to a 24-hour static immersion test. The removal efficiency was determined using LC-QToF and is shown in Table 4.

[0094] Table 4 -Removal of organic matter from ammonia

[0095]

[0096] As shown, porous UPE membranes containing activated carbon removed all target impurities from ammonia compared to porous UPE membranes without activated carbon. The removal efficiency increased with increasing amounts of activated carbon in the membrane.

[0097] Example 6: Determination of metal removal from IPA using a porous UPE membrane containing activated carbon

[0098] The following examples are general examples demonstrating metal removal from UPE membranes using organic solvents such as isopropanol (IPA), propylene glycol methyl ether (PGME), (2-methoxy-1-methylethyl acetate), propylene glycol monomethyl ether acetate (PGMEA), and OK73. TM (70 / 30 blend of propylene glycol methyl ether acetate / propylene glycol methyl ether (PGMEA / PGME)) and cyclohexanone.

[0099] A porous UPE membrane containing activated carbon was prepared using a method similar to that shown in Example 1, and the membrane was then cut into 47 mm diameter discs (samples). The membrane was first washed several times with 10% HCl, then rinsed with DI water, and finally soaked in 10% HCl overnight and equilibrated with deionized water. For each solvent, the 47 mm sample was immersed in a solution containing aqueous metal standards of 21 to 28 metals (SCP Science) to achieve a target concentration of 5 ppb for each total metal. The feed and filtrate samples were then analyzed by an Agilent 8800 ICP-MS (inductively coupled plasma-mass spectrometer) to determine the membrane's ability to remove metal ions from these solvents. The results are shown in Tables 5-9.

[0100] Table 5 Metal removal from IPA was determined using a porous UPE membrane containing activated carbon.

[0101] IPA (removal percentage)

[0102]

[0103]

[0104] Table 6 Metal removal from PGMEA was determined using a porous UPE membrane containing activated carbon.

[0105] PGMEA (Removal %)

[0106]

[0107] Table 7 Metal removal from PGME was determined using a porous UPE membrane containing activated carbon.

[0108] PGME (removal %)

[0109]

[0110]

[0111] Table 8 Metal removal from OK73 was determined using a porous UPE membrane containing activated carbon.

[0112] OK73 TM (Remove %)

[0113]

[0114] Table 9 Metal removal from cyclohexanone was determined using a porous UPE membrane containing activated carbon.

[0115] Cyclohexanone (removed %)

[0116]

[0117] Metal removal efficiency of porous polymeric membranes containing activated carbon was tested using S21 and S28 metal standards from Inorganic Ventures. As demonstrated, carbon-containing membranes remove metals better from organic solvents compared to aqueous solutions. Metal removal using UPE membranes containing 20% ​​(w / w) activated carbon has proven to have higher removal efficiencies (>80%) in most organic solvents compared to aqueous solutions, particularly for metals such as copper (Cu), zinc (Zn), molybdenum (Mo), silver (Ag), cadmium (Cd), and lead (Pb).

[0118] Example 7: Determination of metal removal from dilute peroxides and DIW

[0119] This example demonstrates the ability of porous polymer membranes containing activated carbon to reduce metals in solvents such as dilute hydrogen peroxide and deionized water (DIW) under static immersion conditions.

[0120] The porous UPE membrane containing activated carbon (0.2 μm) prepared as described above was cut into 47 mm discs. These membrane discs were then conditioned by washing several times with 10% HCl and 70% IPA, then soaked overnight in 10% HCl, equilibrated with deionized water, and dried at room temperature. Inorganic Venture Capital Corporation (IV-62491) standard metals were added to the above solvents at a target concentration of 5 ppb for each metal. To determine the metal removal efficiency of static immersion, 20 mL of the metal-doped solvent solution was placed in a PFA bottle containing a 47 mm dried membrane disc and rotated for 18 hours. After 18 hours, the membrane discs were removed, and the metal concentrations in the solvent containing the metal and the supernatant samples of each solvent membrane were determined using ICP-MS. The results are shown in Table 10.

[0121] Table 10 -Removal % from DIW and dilute peroxides

[0122] Added metals Removal % from DIW Removal % from 1% H2O2 Li 0％ 0％ Be 29％ 11％ Na 0％ 0％ Mg 0％ 0％ Al 0％ 0％ K 0％ 0％ Ca 0％ 0％ Ti 46％ 84％ V 88％ 38％ Cr 0％ 0％ Mn 0％ 0％ Fe 0％ 20％ Co 1％ 22％ Ni 0％ 0％ Zn 0％ 0％ Cu 0 0％ Ge 39％ 38％ As 87％ 0％ Sr 41％ 53％ Mo 95％ 99％ Ag 99％ 98％ Cd 36％ 36％ In 0％ 27％ Sn 92％ 99％ Sb 40％ 17％ Ba 35％ 74％ Ta 94％ 100％ W 99％ 98％ Tl 22％ 8％ Pb 22％ 91％

[0123] As shown, effective metal removal was observed. For the metals that were not removed, it is believed that the activated carbon incorporated in the PE film will also cause the metals to detach.

[0124] Example 8: Metal removal from SC1 (DIW:NH4OH:H2O2 (5:1:1))

[0125] This example demonstrates the ability of a porous UPE membrane containing activated carbon to remove target metals from corrosive applications, such as SC1, under static immersion conditions. Nine target metals (Al, Ca, Cr, Cu, Fe, Mn, Ni, Ti, and Zn) from Inorganic Ventures (IV-62491) were added to a freshly prepared SC1 solution at a concentration of 5 ppb for each metal. A 47 mm membrane disk was cut and washed overnight in 10% HCl / 70% IPA, followed by equilibration with deionized water. The membrane disk was further purified with the freshly prepared SC1 solution and then immersed in the aforementioned metal-doped solution for 16 hours. After 16 hours, the membrane disk was removed, and the metal removal efficiency was measured by ICP-MS. The results are reported as removal percentage (%) in Table 11.

[0126] Table 11 -Removal % from SC1

[0127]

[0128] Example 9: Removal of organic pollutants from DIW

[0129] The following example demonstrates the removal of organic impurities from DIW. A porous UPE membrane containing activated carbon was prepared using a method similar to that shown in Example 1, and then cut into 47 mm membrane disks. The removal percentage of organic impurities was determined by immersing the membrane disks in 20 ml of DIW solution containing the target impurities, and the removal efficiency was measured by LC-QToF. The results are summarized in Table 12.

[0130] Table 12 -Removal from DIW %

[0131]

[0132] aspect

[0133] In a first aspect, the porous polymeric membrane comprises a polymer incorporating a carbon-containing material of greater than zero and less than about 80% by weight, wherein the membrane exhibits:

[0134] (a) When measured using ethoxy-nonafluorobutane HFE 7200 at a temperature of approximately 22°C, the bubble point is approximately 2 psi to approximately 200 psi.

[0135] (b) Isopropanol flow time from approximately 20 seconds / 500 mL to approximately 10,000 seconds / 500 mL when measured at 14.2 psi, and

[0136] (c) G25 particle retention of approximately 25% to approximately 100%.

[0137] According to the second aspect of the first aspect, the carbon-containing material mentioned therein is selected from the group consisting of: activated carbon, carbon black, carbon nanotubes, and graphene.

[0138] According to the third aspect of the first or second aspect, the carbon-containing material therein is in the form of powder, particulate material, fiber or sheet.

[0139] According to the fourth aspect of any of the foregoing aspects, the G25 particles are retained at 5% of the monolayer, which is approximately 65% ​​to approximately 80%.

[0140] According to the fifth aspect of any of the foregoing aspects, the membrane described therein exhibits a bubble point of about 10 psi to about 40 psi.

[0141] According to the sixth aspect of any of the foregoing, the membrane described therein exhibits an isopropanol flow time of approximately 845 seconds / 500 ml to approximately 1665 seconds / 500 ml when measured at 14.2 psi.

[0142] According to the seventh aspect of any of the foregoing aspects, the polymer contains less than about 65 μg / g of extractable organic compounds and / or metal ions.

[0143] According to the eighth aspect of any of the foregoing aspects, the polymer is not polysulfone or poly(tetrafluoroethane).

[0144] According to the ninth aspect of any of the foregoing aspects, the polymer is mixed with about 10 to about 80% by weight of the carbon-containing material.

[0145] According to the tenth aspect of any of the preceding aspects, the membrane has a thickness of about 35 to about 400 μm.

[0146] According to the eleventh aspect of any of the preceding aspects, the polymer is selected from the group consisting of: polyamides, polyimides, polyolefins, polyethersulfones, polyacrylates, polyesters, cellulose, cellulose esters, polycarbonates, poly(phenylene ether), poly(styrene), halogenated polymers, and combinations thereof.

[0147] In the twelfth aspect, the filter comprises a porous polymeric membrane according to technical solution 1.

[0148] In the thirteenth aspect, the composite membrane comprises a first porous polymer membrane and a second porous polymer membrane.

[0149] The outer surface of the first porous polymer membrane is in contact with the outer surface of the second porous polymer membrane.

[0150] The first porous polymer membrane comprises a first polymer in which a first carbon-containing material is mixed in greater than zero and less than about 80% by weight.

[0151] The second porous polymer membrane is different from the first porous polymer membrane.

[0152] According to the fourteenth aspect of the thirteenth aspect, the outer surface of the first porous polymer membrane is the output-facing surface, and the outer surface of the second porous polymer membrane is the input-facing surface.

[0153] According to the thirteenth or fourteenth aspect, the fifteenth aspect is a co-cast membrane of a first porous polymer membrane and a second porous polymer membrane.

[0154] In the sixteenth aspect, the filter comprises the composite membrane according to claim 13.

[0155] In a seventeenth aspect, a method for preparing a porous polymeric membrane, the porous polymeric membrane comprising a polymer incorporating a carbon-containing material, the method comprising:

[0156] a. Combining a carbon-containing material with a flowable form of a polymer, wherein the polymer has been (i) blended with an effective amount of at least one solvent and / or dispersant to provide a flowable form; and / or (ii) heated to a temperature sufficient to provide a flowable form;

[0157] b. Dispersing a carbon-containing material into a polymer, thereby providing a polymer composition in which a carbon-containing material is incorporated; and

[0158] c. If present, remove the solvent or dispersant, and / or cool the polymer composition to form the porous polymeric membrane.

[0159] According to the seventeenth aspect and the eighteenth aspect, the polymer is selected from polyamide, polyimide, polyolefin, polyethersulfone, polyacrylate, polyester, cellulose, cellulose ester, polycarbonate, poly(phenylene ether), poly(styrene), halogenated polymers or combinations thereof.

[0160] According to the 19th aspect of the 17th or 18th aspect, the polymer contains a carbon-containing material of greater than zero and less than about 80% by weight.

[0161] In the twentieth aspect, the method for removing impurities from a liquid composition comprises:

[0162] The liquid composition is brought into contact with the porous polymer membrane according to claim 1, wherein the liquid composition comprises liquid chemicals and one or more impurities, and

[0163] A purified liquid composition comprising the liquid chemical and a reduced amount of the one or more impurities is formed.

[0164] According to the 21st aspect of the 20th aspect, the liquid chemical is a ketone or an alcohol.

[0165] According to the 22nd aspect of the 20th or 21st aspect, the liquid chemicals are organic materials selected from the group consisting of: methyl pentyl ketone, ethyl 3-ethoxypropionate, propylene glycol methyl ether (PGME), propylene glycol methyl ether acetate (PGMEA), propylene glycol monomethyl ether (PGME) and PGMEA (e.g., 7:3), methanol, ethyl acetate, butyl lactate, n-butyl acetate (nBA), isopropanol (IPA), 2-ethoxyethyl acetate (2EEA), xylene, cyclohexanone, methyl isobutyl methanol (MIBC), methyl isobutyl ketone (MIBK), isoamyl acetate, undecane and combinations thereof.

[0166] According to aspect 23 of aspects 20 to 22, the liquid chemicals are amine solvents selected from the group consisting of: ammonia, hydroxylamine, monoethanolamine (MEA), triethanolamine (TEA), morpholine, N-methyldiethanolamine (MDEA), N-monomethylethanolamine (MMEA), N-ethylaminoethoxyethanol, 2-(2-aminoethoxy)ethanol, tetraethylammonium hydroxide (TEAH), tetrabutylammonium hydroxide, and combinations thereof.

[0167] According to the 24th aspect of aspects 20 to 23, the liquid chemicals are deionized water, hydrogen peroxide, hydrochloric acid, sulfuric acid, or combinations thereof.

[0168] According to aspect 25 of aspects 20 to 24, the one or more impurities mentioned therein are metal ions, acids, bases, peroxides, or organic contaminants.

[0169] According to aspect 26 of aspects 20 to 25, the purified liquid composition contains not less than 99.99% by weight of liquid chemicals and one or more impurities totaling not more than about 2000 ppb.

[0170] According to aspect 27 of aspects 20 to 26, one or more impurities include organic amine impurities selected from triethylamine, N,N-diisopropylamine, heptamine, and 3,3,5,5-tetramethylbenzidine.

[0171] According to aspect 28 of aspects 20 to 27, one or more impurities contain metal ions, and the purified liquid composition contains metal ions in total not exceeding about 12 ppb.

[0172] According to the 29th aspect of the 28th aspect, the metal ions are selected from the group consisting of: magnesium, aluminum, titanium, vanadium, manganese, nickel, copper, zinc, molybdenum, silver, cadmium, tin, lead and combinations thereof.

[0173] In the thirtieth aspect, the purified liquid composition is purified according to the method described in claim 20.

Claims

1. A porous polymeric membrane comprising a polyolefin polymer in which more than 20% by weight and less than 80% by weight of a carbon-containing material is mixed, wherein the average particle size of the carbon-containing material is in the range of 30 μm to 60 μm, wherein the porous polymeric membrane exhibits: (a) Bubble points from 2 psi to 200 psi when measured using ethoxy-nonafluorobutane HFE 7200 at 22°C. (b) Isopropanol flow time from 20 sec / 500 mL to 10,000 sec / 500 mL when measured at 14.2 psi, and (c) 25% to 100% G25 particle retention.

2. The porous polymer membrane according to claim 1, wherein the polyolefin polymer is ultra-high molecular weight polyethylene.

3. The porous polymeric membrane according to claim 2, wherein the membrane has an isopropanol flow time of 500 sec / 500 mL to 2500 sec / 500 mL when measured at 14.2 psi.

4. The porous polymeric membrane according to claim 2, wherein the membrane has a bubble point of 10 psi to 40 psi when measured using nonafluorobutane HFE 7200 at a temperature of 22°C.

5. The porous polymeric membrane according to claim 2, wherein the membrane has a G25 particle retention rate of 65% to 80% at 5% monolayer.

6. The porous polymer membrane according to claim 2, wherein the porous polymer membrane has a thickness of 80 μm to 350 μm.

7. The porous polymer membrane according to claim 1, wherein the carbon-containing material is selected from the group consisting of: activated carbon, carbon black, carbon nanotubes, and graphene.

8. The porous polymer membrane according to claim 1, wherein the carbon-containing material is in the form of powder or particulate material.

9. A filter comprising a porous polymeric membrane according to any one of claims 1-8.

10. A composite membrane comprising a first porous polymer membrane and a second porous polymer membrane, The outer surface of the first porous polymer membrane is in contact with the outer surface of the second porous polymer membrane, wherein the first porous polymer membrane is a porous polymer membrane according to any one of claims 1-8, and wherein the second porous polymer membrane is different from the first porous polymer membrane.

11. A method for preparing a porous polymeric membrane according to any one of claims 1-8, the method comprising: a. Combining the carbon-containing material with the polyolefin polymer in a flowable form, wherein the polyolefin polymer has been (i) mixed with an effective amount of at least one solvent and / or dispersant to provide the flowable form; and / or (ii) heated to a temperature sufficient to provide the flowable form; b. Dispersing the carbon-containing material into the polyolefin polymer to provide a polyolefin polymer composition in which the carbon-containing material is mixed; and c. If present, remove the solvent or dispersant, and / or cool the polyolefin polymer composition to form the porous polymeric membrane.

12. A method for removing impurities from a liquid composition, the method comprising: The liquid composition is contacted with the porous polymeric membrane according to any one of claims 1-8, wherein the liquid composition comprises liquid chemicals and one or more impurities, and To form a purified liquid composition comprising the liquid chemical and a reduced amount of the one or more impurities.

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