Provided is a filtration method that includes a cleaning step and involves the use of a porous membrane, wherein the filtration method offers exceptional resistance to cleaning solutions (chemicals) (chemical liquid resistance) and exceptional filtration performance, and has a long service life. A filtration method includes the following steps: a filtration step in which a liquid to be processed that contains a material to be filtered is passed through a porous membrane configured from a resin having a three-dimensional mesh structure, and a filtrate is separated from the material to be filtered; and a cleaning step in which the porous membrane has a cleaning solution passed therethrough or is immersed in the cleaning solution so that the interior of the porous membrane is cleaned.

Provided is a porous polytetrafluoroethylene membrane in which an absolute value of a difference in lightness between one principal surface and the other principal surface is 1.0 or more, where the lightness is lightness L* of CIE 1976 (L*, a*, b*) color space specified in JIS Z8781-4: 2013. The porous polytetrafluoroethylene membrane may be colored black or gray. The porous polytetrafluoroethylene membrane provided can have properties with a reduced coloring-induced deterioration.

Provided are porous polymeric filter membranes comprising a polymer having admixed therein at least one carbonaceous material. The membranes are capable of removing trace amounts of various impurities from a liquid composition, including metal ions, acids, bases, and organic contaminants.

A membrane is described for purifying or separating hydrogen from a multi-component gas stream such as syngas. This membrane uses a molecular pre-treatment, a transition metal, fluorine containing polymer, carbon fibers and carbon matrix sintered on a supportive screen. The membrane may be a bilayer membrane comprised of a layer containing high surface area carbon and another layer containing lower surface area carbon. Methods for purifying hydrogen are also described.

A membrane is described for purifying or separating hydrogen from a multi-component gas stream such as syngas. This membrane uses a molecular pre-treatment, a transition metal, fluorine containing polymer, carbon fibers and carbon matrix sintered on a supportive screen. The membrane may be a bilayer membrane comprised of a layer containing high surface area carbon and another layer containing lower surface area carbon. Methods for purifying hydrogen are also described.

A nanocarbon immobilized membrane (NCIM) is disclosed. The nanocarbon immobilized membrane is sized to purify different organic-water mixtures. The nanocarbon immobilized membrane can be used to purify solvents, fuels, and other organic compounds. Data using heptane-water, octane-water, fuel-water, and paint thinner-water show 99.9% separation efficiency. High organic flux is also seen at relatively low pressure. This approach has numerous applications, including fuel purification, oil spills clean-up, separation of commercial emulsions, and solvent purification.

A nanocarbon immobilized membrane (NCIM) is disclosed. The nanocarbon immobilized membrane is sized to purify different organic-water mixtures. The nanocarbon immobilized membrane can be used to purify solvents, fuels, and other organic compounds. Data using heptane-water, octane-water, fuel-water, and paint thinner-water show 99.9% separation efficiency. High organic flux is also seen at relatively low pressure. This approach has numerous applications, including fuel purification, oil spills clean-up, separation of commercial emulsions, and solvent purification.

Described are filter materials including a polyol ligand, such as n-methylglucamine, and/or a polyphosphonic acid ligand, which are highly effective for filtering metals or metal ions from fluids. The filter materials can be particularly useful to filter basic and acidic fluid compositions, such as those used for wet etching, removing photoresist, and cleaning steps in microelectronic device manufacturing.

Described are filter materials including a polyol ligand, such as n-methylglucamine, and/or a polyphosphonic acid ligand, which are highly effective for filtering metals or metal ions from fluids. The filter materials can be particularly useful to filter basic and acidic fluid compositions, such as those used for wet etching, removing photoresist, and cleaning steps in microelectronic device manufacturing.

Some embodiments of the present disclosure relate to a method of regenerating at least one filter medium comprising: providing at least one filter medium, wherein the at least one filter medium comprises: at least one catalyst material; and ammonium bisulfate (ABS) deposits, ammonium sulfate (AS) deposits, or any combination thereof; flowing a flue gas stream transverse to a cross-section of a filter medium, such that the flue gas stream passes through the cross section of the at least one filter medium, wherein the flue gas stream comprises: NOx compounds comprising: Nitric Oxide (NO), and Nitrogen Dioxide (NO.sub.2); and increasing an NOx removal efficiency of the at least one filter medium after removal of deposits.