Membranes are provided for filtering a gas, in some cases air. Membranes using a highly porous cellulose nano fibrous barrier layer with a highly porous (surface-charged) substrate can exhibit high flux, high retention, and low pressure drop in air filtration of toxic aromatic gases, fumes, bacteria, viruses, dusts, and particulate matters.

A hand-carry gravity-driven water filter with high throughput and water disinfection performance is formed. Membranes used for this water filter can be fabricated using electrospun method and non-solvent induced phase inversion method. A novel composite membrane structure (interwoven composite structure) was designed for further enhances water permeability and mechanical strength. The composite membrane can be composed of nanofibers with different diameter from the same polymer or different polymers. Membrane porosity and surface pore size can be controlled. Silver nanoparticles can be in-situ loaded on the surface of the membranes. The developed filter is effective for removal of a wide range of contaminants (e.g., pathogens, suspended solids and heavy metals). The purification process can be carried out under the drive of gravity (with an option for mechanically-enhanced filtration) without electricity.

A method for controlling fiber cross-alignment in a nanofiber membrane, comprising: providing a multiple segment collector in an electrospinning device including a first and second segment electrically isolated from an intermediate segment positioned between the first and second segment, collectively presenting a cylindrical structure, rotating the cylindrical structure around a longitudinal axis proximate to an electrically charged fiber emitter; electrically grounding or charging edge conductors circumferentially resident on the first and second segment, maintaining intermediate collector electrically neutral; dispensing electrospun fiber toward the collector, the fiber attaching to edge conductors and spanning the separation space between edge conductors; attracting electrospun fiber attached to the edge conductors to the surface of the cylindrical structure, forming a first fiber layer; increasing or decreasing rotation speed of the cylindrical structure to alter the angular cross-alignment relationship between aligned nanofibers in adjacent layers, the rotation speed being altered to achieve a target relational angle.

A method for producing a microstructured air-permeable environmental barrier membrane includes providing a substrate, and structuring a through hole into the substrate, the through hole extending fully through the substrate between two opposite surfaces of the substrate, leaving the through hole uncovered, and depositing one or more nanofibers onto at least one of the two opposite substrate surfaces by applying at least one of an electrospinning or blowspinning method, such that the spun nanofibers combine to a network of nanofibers that forms a free-standing and mechanically compliant nanofibrous membrane covering the previously uncovered through hole.

A dispersion liquid including a fiber material which is capable of forming a porous film having high porosity; a porous film formed using the dispersion liquid; a power storage element including the porous film; and a method for producing a porous film using the dispersion liquid. In the dispersion liquid including the fiber material and an organic solvent, which is used for forming a porous film by applying and drying, the fiber material contains a predetermined amount of a modified cellulose fiber including a carboxy group or a metal salt thereof, and the amount of water in the dispersion liquid is 5% by mass or less.

Titanium dioxide/sulfonated graphene oxide/silver nanoparticle composite membrane and its preparation method and application are disclosed. Mixing graphene oxide, sodium chloroethanesulfonate, and sodium hydroxide uniformly in the water, and then adding concentrated nitric acid to obtain sulfonated graphene oxide; mixing the aqueous solution of said sulfonated graphene oxide with the aqueous solution of silver nitrate, stirring in the dark, then adding ascorbic acid, and continuing to stir to obtain a silver nanoparticle/sulfonated graphene oxide composite material; dispersing said silver nanoparticle/sulfonated graphene oxide composite material in water, and then deposited on said titanium dioxide nanorods arrays by vacuum deposition, and vacuum dried to obtain titanium dioxide/sulfonated graphene oxide/silver nanoparticle composite membrane. The membrane possessed photocatalytic effect under UV light and special wettability: super-hydrophobic oil under water/super-hydrophobic under oil, which could in situ separation and degradation of oil/water emulsion.

A method for removing retroviruses from liquid samples and a nanofiber containing liquid filtration medium that simultaneously exhibits high liquid permeability and high microorganism retention is disclosed. Retroviruses are removed from a liquid by passing the liquid through a porous nanofiber containing filtration medium having a retrovirus LRV greater than about 6, and the nanofiber(s) has a diameter from about 10 nm to about 100 nm. The filtration medium can be in the form of a fibrous electrospun polymeric nanofiber liquid filtration medium mat.

A homogeneous composite substrate includes a woven cloth and at least one fiber membrane. The woven cloth includes a plurality of first fibers. The fiber membrane is disposed on at least one surface of the woven cloth, and the fiber membrane includes a plurality of second fibers, in which a material of the first fibers and a material of the second fibers are the same, a fiber diameter of each first fiber is larger than or equal to 20 ?m and smaller than or equal to 130 ?m, and a fiber diameter of each second fiber is larger than or equal to 3 ?m and smaller than or equal to 10 ?m.

A tunable nanofiber filter device can include a filter housing defining an interior space, the housing having defined therein and inlet and an outlet, each in fluid communication with the interior space, and a plurality of filter laminas disposed within the interior space, each filter lamina including an upper surface, a lower surface, and an aperture defined therethrough. The plurality of filter laminas can be arranged in a stack wherein the opposing surfaces of adjacent filter laminas define a portion of an interlaminar flow space extending between the opposing surfaces. The flow space can be in fluid communication with the apertures of corresponding adjacent filter laminas to form a continuous flow passage extending through the lamina stack from the inlet to the outlet. An array nanofibers can extend into the flow passage from a portion of each filter lamina such that a fluid flowed through the flow passage flows across a portion of said array.

The invention is contemplated for providing polyethylene-based fibers in which elution of metal from polyethylene is suppressed as much as possible. The invention relates to polyethylene-based fibers, composed of at least one kind of polyethylene resin, in which a total of content of metal elements such as Na, K, Ca, Fe, Cu, Mg, Mn, Li, Al, Cr, Ni and Zn contained inside the fibers is 40 ppm or less. Moreover, the invention relates to a nonwoven fabric using the polyethylene-based fibers.