Articles and methods relating to filter media are generally provided. In some embodiments, a filter media has an irregular surface structure. For instance, the filter media may comprise a plurality of peaks that are irregular in one or more ways. A ratio of a peak height standard deviation to an average peak height may be greater than or equal to 0.05, and/or a ratio of a peak spacing standard deviation to an average peak spacing may be greater than or equal to 0.08. In some embodiments, a filter media comprises a non-woven fiber web having a layer thickness of greater than 0.3 mm and/or a stiffness of less than or equal to 100 mg.

This disclosure describes a high performing (including, for example, high efficiency and low pressure drop) filter media. The filter media includes a support layer and a layer of fine fibers wherein at least some of the fine fibers in the fine fiber layer having an average diameter at least 3 times the average fiber diameter of a smaller fine fiber in the fine fiber layer. The fine fiber layer may include multiple layers of fine fibers. In some aspects, the smaller fine fiber may be present in the same layer of fine fibers as the larger fine fibers. Additionally or alternatively, the larger fine fibers may be present in a first layer of fine fibers and the smaller fine fibers may be present in a second layer of fine fibers.

The present disclosure provides a unique fine fiber material that is formed from a fiber-forming polyamide with a fluorochemical urethane additive, a method of making such fiber material, as well as filter media and filter elements including such fibers.

A fabrication method for a water-absorbent filter includes obtaining a homogenized tragacanth suspension by dissolving tragacanth in a solvent, where the solvent may include distilled water, ethyl acetate, acetic acid, and formic acid, obtaining a support layer by coating a stainless steel mesh with a thin layer of a hydrophobic polymer, coating a stainless steel mesh with the thin layer of the hydrophobic polymer comprising electrospinning a hydrophobic polymer solution onto the stainless steel mesh, forming a tragacanth nanofibrous web on the support layer by electrospinning the homogenized tragacanth suspension onto the support layer, and cross-linking the tragacanth nanofibrous web by exposing the tragacanth nanofibrous web to a saturated vapor of a cross-linking agent.

A multi-layered replaceable filter assembly (100) and a microfilter assembly (200) for providing safety from external exposure. The multi-layered micro filter assembly includes plurality of filter membranes. A first filter membrane (104) prevents particles greater than 10 micron from entering the multi-layered replaceable filter assembly (100). A second filter membrane (106) has embedded activated carbon that destroys micro-organisms including viruses and bacteria. As we go further downstream, the fiber density per cm keeps increasing with the filter membranes. A fifth filter membrane (112) made up of a combination of crabyon fiber and electro-spun nano fibers provides comfort and anti-allergic effect. A sixth filter membrane (114) lowers the velocity of air that occurs from breathing and a method thereof.

Filter media comprising nanofibers and related components, systems, and methods associated therewith are provided. In some embodiments, a filter media may comprise a first fiber web and a second fiber web designed to impart beneficial properties to the filter media. For instance, in some embodiments, the first fiber web may provide high particulate efficiency and the second fiber web may provide suitable capacity. In some embodiments, the first and second fiber webs may have certain properties (e.g., water contact angle, surface energy) that are similar or substantially the same. The similarities between the first and second fiber webs may serve to enhance the structural stability of the filter media under various conditions (e.g., high temperature, high pressure, steam sterilization) and/or permeability to certain fluids (e.g., water). Filter media, as described herein, may be particularly well-suited for applications that involve liquid filtration.

Articles and methods involving filter media are generally provided. In certain embodiments, the filter media includes at least a first layer, a second layer, and an adhesive resin positioned between the first layer and the second layer. In some embodiments, the first layer may be a pre-filter layer or a support layer. The second layer may, for example, comprise fibers formed by a solution spinning process and/or may comprise fine fibers. In some embodiments, the adhesive resin may be present in a relatively low amount and/or may have a low glass transition temperature. The filter media as a whole may have one or more advantageous properties, including one or more of a high stiffness, a high bond strength between the first layer and the second layer, a high gamma, and/or a low increase in air resistance after being subjected to an IPA vapor discharge. The filter media may be, for example, a HEPA filter and/or an ULPA filter.

A fibrous mat is provided for use in taking a metabolome sample and for use in desorption of the metabolome sample. The fibrous mat includes an open network of at least one polymer-based nanofiber. The diameter of the at least one nanofiber ranges between 50 nm and 1500 nm, and a cover layer is provided at a top and/or at a bottom of the open network of at least one nanofiber to exclude particles with a size larger than 2000 Da from interacting with the open network of at least one nanofiber by blocking and/or excluding access to these particles.

The present disclosure provides an electrospinning method for fabricating a nanofiber air filter with a minimized pressure drop. The method comprises following steps:S1. dissolving a specified amount of powder polymer material in a solvent, and magnetically stirring a resulting solution; adding the solution to a syringe connected with a microneedle by a plastic tube, and pumping the solution by the syringe into an electrospinning machine;S2. allowing the electrospinning machine to work under a high voltage, such that the solution generates nanofibers; the nanofibers are interweaved to fabricate air filters for removing particles in air with a particle removal efficiency η(V.sub.m, t.sub.n) and pressure drop ΔP(V.sub.m, t.sub.n), V.sub.m is electrospinning voltage and t.sub.n is electrospinning time; andS3. finding optimal electrospinning voltage V.sub.opt and optimal electrospinning time t.sub.opt, such that an air filter fabricated by V.sub.opt and t.sub.opt can achieve target particle removal efficiency η.sub.tar and minimized pressure drop ΔP.sub.min.

A method for preparing a porous nano-fiber heterostructure photocatalytic filter screen includes: preparing a noble metal nanostructure with tunable spectra and a heterostructure composite photocatalyst of a photocatalytic material; and preparing a large area and multilayer porous nano-fiber filter screen structure, while utilizing a scattering enhancement effect of metal nanoparticles in an porous optical fiber to realize repeated conduction of sunlight in the optical fiber and finally interact with the composite photocatalyst on a surface to improve photocatalytic efficiency. Preparation of the heterostructure composite photocatalyst with a wide spectral response of and tunable visible to infrared band spectra is realized, at the same time, with reference to high adsorbability, high light transmission of nanometer fiber and unique optical characteristics of metal nanoparticles, an air purification filter screen with a high sunlight utilization rate and a high catalytic degradation capability is creatively provided.