Proposed is a multi-layer filtration system including a metal catalyst filter unit, a carbon filter unit, and an inorganic compound filter unit. The metal catalyst filter unit includes at least one among metals including Ni, Co, Fe, Cu, Cr, Mg, Zn, Ba, Au, Ag, Pd, Pt, Ru, Mn, and Ti, oxides thereof, and mixtures thereof. The carbon filter unit includes at least one of activated carbon or activated carbon fiber. The inorganic compound filter unit includes an inorganic compound capable of adsorbing toxic gas. The multi-layer filtration system has good removal effect for toxic gas. A filter module including the multi-layer filtration system and a gas mask including the multi-layer filtration system are also proposed.

A face mask and a removable insert, the insert being constructed primarily of cidal metal or cidal metal alloy wherein the cidal metal or cidal metal alloy is the major structural component of the insert. The insert is positioned on the face mask to cover at least a portion of the wearer's mouth and nose when the mask is worn on the wearer's face. The insert has a filtering portion comprising cidal metal mesh or cidal metal alloy mesh to provide cidal action, air purification, and self-disinfection.

The present invention relates to a filter unit (100, 301) for filtering a fluid (105) for the operation of a fuel cell. The filter unit (100, 301) comprises at least one filter element (101) filled with a filter material (103) comprising cyclodextrin. The presented Invention also relates to a fuel cell system, to the use of cyclodextrin to filter a fluid for the operation of a fuel cell system, and to a method for operating a fuel cell system.

The present invention relates to a filter assembly for filtering a body fluid comprising a filter holder and a filter system downstream of the filter holder; wherein the filter system and the filter holder are in contact with each other, wherein the filter system comprises a cuboid frame structure with six rectangular surface areas A1-A6, and wherein five of the six surface areas A1-A5 are covered by a filtering media, and wherein the sixth surface area A6 is in contact with the filter holder.

Air filters, and air filter devices for use in helicopters, and methods of use, are disclosed.

Described herein is an antiviral face mask and methods of use thereof to inactivate a virus in contact with the face mask. The face mask may include a fibrous material with silicon nitride powder impregnated therein and a layer surrounding the fibrous material. In some embodiments, silicon nitride is present in the fibrous material at a concentration of about 30 wt. % to about 50 wt. %.

A mask assembly comprising a face covering portion, a pocket connected to the face portion and positioned to cover a wearer’s nose and mouth, where in a filter is removably inserted into the pocket, the filter comprising a porous hydrophobic and lipophobic layer, a diamond - like carbon coated copper layer, and a non- woven fabric layer. A filter containing at least one porous hydrophobic and lipophobic layer, at least one diamond like carbon coated copper layer interposed between two non-woven fabric layers, and at least one additional non- woven fabric layer. A filter comprising at least one porous hydrophobic and lipophobic layer, at least one diamond - like carbon coated copper layer, and at least one non - woven fabric layer, the at least diamond-like carbon coated layer is between the at least one porous hydrophobic and lipophobic layer and at least one non - woven fabric layer.

The invention relates to a filtering material permeable to air and impermeable to oral, nasal and/or ocular human liquid aqueous excretions, comprising at least one bundle, referred to as a hydrophobic bundle, of at least two hydrophobic sheets which are superimposed and each formed by porous paper, having a gsm substance less than 30 g/m.sup.2, each hydrophobic sheet being formed by cellulose fibres, referred to as cross-linked cellulose fibres, which are connected to each other by hydrogen bonds and by covalent bonds which are formed with at least one group of cross-linking atoms, characterised in that at least some of the hydroxyls of the cross-linked cellulose fibres which are not engaged in hydrogen bonds and which are accessible to the gases form a covalent bond with an acyl group with a hydrophobic chain.

An object of the present invention is to provide a chemical liquid purification method by which a chemical liquid capable of inhibiting the occurrence of short in a semiconductor substrate manufactured by a photolithography process is obtained. Another object of the present invention is to provide a chemical liquid manufacturing method and a chemical liquid. The chemical liquid purification method of the present invention includes a purification step of filtering a liquid to be purified by using a filter, in which a filter satisfying a condition 1 or a condition 2 in the following test is used as the filter. Test: 1,500 ml of a test liquid formed of the organic solvent is brought into contact with the filter for 24 hours under a condition of 23° C., and a content of particles containing at least one kind of metal selected from the group consisting of Fe, Al, Cr, Ni, and Ti in the test liquid after the contact satisfies a predetermined condition.

A filter insert, a sample vial incorporating a filter insert, a method of using a sample vial containing a filter insert for chemical analysis, and a sample vial kit including a filter insert. The filter insert includes a cylindrical body having a proximal end, a protrusion extending radially from the proximal end of the cylindrical body and configured to set on the open end of a sample vial, a distal end, a cavity extending longitudinally through the cylindrical body from the proximal end to the distal end, and a filter assembly coupled with the distal end of the cylindrical body.