Filter media comprising non-woven fiber webs and having one or more advantageous structural properties are generally described. In some embodiments, a filter media and/or non-woven fiber web described herein has one or more properties that are both beneficial and easily obtainable by undulating the non-woven fiber web, such as by performing a creping procedure. This property may be characteristic of the procedure employed to form the undulations (e.g., creping and/or microcreping), or may be attainable via one or more methods of undulation.

Disclosed is a filter medium useful for flue gas filtering that comprises a non-woven fibrous web having at least 80 weight percent of meta-aramid fibers and from 0.1 to 20 weight percent of meta-aramid fibrids, based on weight of fibers and fibrids. The non-woven fibrous web can have average pore size of 20 to 80 micrometers, maximum pore size of 100 micrometers, dry Mullen burst strength of at least 7 kg/cm.sup.2, retention of 80% of the dry Mullen burst strength after acid cycling, a filtration efficiency of at least 95% for 2.5 micron particle, and/or a shrinkage of less than 2% after being heated in a dry oven at 205 ° C. for 2 hours. A method of making the filter medium comprises wet-laying a furnish of the meta-aramid fibers and the meta-aramid fibrids; drying to form the non-woven fibrous web; preferably, calendering; and optionally saturating with binder resin and curing.

A spinel-reinforced magnesium oxide-based foam ceramic filter that is obtained by coating onto a polyurethane foam carrier a slurry of light calcined magnesium oxide-based ceramic comprising a nanometer lanthanum oxide sintering aid, and then drying and sintering. A method for preparing the foam ceramic filter comprising: 1) preparing a ceramic slurry having a solid content of 60%-70% by dosing 15%-25% by mass of a nanometer alumina sol, 0.8%-1.5% by mass of a rheological agent, and the balance magnesium oxide ceramic powder comprising a nanometer lanthanum oxide sintering aid, and then adding absolute ethanol and ball milling to mix until uniform; 2) soaking a polyurethane foam template into the ceramic slurry, squeezing by a roller press the polyurethane foam template to remove redundant slurry therein to make a biscuit, and then removing the ethanol solvent in a ventilation chamber at a temperature of 40° C.-50° C. to dry the biscuit; 3) putting the dried biscuit into a sintering furnace, elevating the temperature to 1350° C.-1550° C. and performing a high temperature sintering, cooling to the room temperature with the furnace to obtain the magnesium oxide-based ceramic foam filter.

Provided are: a filter medium with high dust collection efficiency, low pressure loss, and a long lifespan; and a filter material used for the filter medium. This composite structure includes ultrafine fibers having a fiber diameter of less than 500 nm, and beads. The outermost surface of the composite structure has at least 500/mm.sup.2 of beads with a diameter of 5 μm or more. The ultrafine fibers and the beads preferably have the same component.

Provided are an air filter medium and an air filter product that can have a long life. The air filter medium includes a filter medium layer that includes first fibers having an average fiber diameter of not less than 5 μm and not greater than 50 μm and second fibers disposed in gaps between the first fibers and having an average fiber diameter of not less than 30 nm and not greater than 1 μm.

A filter media having lignite-derived activated carbon, polyacrylic acid (PAA), a commercially available copper-zinc alloy, and polydiallyldimethylammonium chloride (PolyDADMAC) or Luviquat®, which is Poly[(3-methyl-1-vinylimidazolium chloride)-co-(1-vinylpyrrolidone)], combined and used as suitable replacement for TOG bituminous coal-based activated carbon, silver, and PolyDADMAC. Functional groups in lignite-based activated carbon interact with the polyacrylic acid. Functional groups such as calcium, iron, or aluminum oxide/hydroxide of lignite-based activated carbon interact with PAA, and help hold the PolyDADMAC in place. The additional presence of a copper-zinc alloy enhances the filter anti-microbiological performance.

The present invention provides a formulation and method for preparing a fibrous material comprising nanofibers. The formulation comprises (a) at least one polymer, (b) at least one solvent in which the at least one polymer is dissolved to provide a polymer solution, and (c) at least one functional additive that imparts functionality to the fibrous material. The at least one functional additive is dissolvable or suspensible in the polymer solution. The formulation is able to remove or reduce the concentration of bacteria, viruses and heavy metals while maintaining high filtration efficiency. The invention also relates to a fibrous material prepared by the formulation and applications of the fibrous material.

Producing a filtration body formed of a layered double hydroxide having a crystallite size of 20 nm or less carried on a carrier including a thermally fusible fiber is described. The carrier is prepared that has a first mesh carrier having a first mesh size and a second mesh carrier provided above the first mesh carrier. The second mesh carrier has a second mesh size larger than the first mesh size. A layered double hydroxide in the form of granules is supplied toward the second mesh carrier. The first mesh carrier carries the layered double hydroxide that has passed through the second mesh carrier. The carrier is shaken so that a portion of the layered double hydroxide (e.g., at least one granule) passes through the first and second mesh carriers. Thereafter, the layered double hydroxide carried on the first mesh carrier is adhered by thermally fusing the thermally fusible fiber.

Filter media and filters comprising a fibrous material, a bonding material, and a flame-resistant treatment composition are disclosed herein. Methods of making and using the same are also disclosed herein.

The present disclosure relates to a mask having improved capability of blocking harmful substances, the mask including: a mask main body including at least one main body sheet; and an earring unit which is formed on both side surfaces of the mask main body, and including a coating layer which is formed on at least one surface of the main body sheet and comprises a TiO.sub.2-based nonphotocatalyst that is activated without irradiation of the solar light to decompose the harmful substances, wherein the nonphotocatalyst comprises: titanium dioxide (TiO.sub.2) having a band gap of 3.0 to 3.2 eV; and a transition metal doped with the titanium dioxide, and generates electrons through a spontaneous reaction by making Gibbs free energy change values into negative numbers.