A bacterial cellulose-based air filter mesh and use thereof are disclosed. The bacterial cellulose-based air filter mesh comprises a three-layer structure, in which a layer of a bacterial cellulose-based filter mesh is sandwiched by two layers of polymer fiber filter meshes; wherein the polymer fiber filter mesh is a mesh having a uniform grid size formed from polymer fibers by blended-yarn weaving; and the bacterial cellulose-based filter mesh is formed by in-situ synthesis of bacterial cellulose on a non-woven fabric through fermentation by bacteria. The bacterial cellulose-based air filter mesh has better particle filtering effect, better formaldehyde adsorption capacity, better antibacterial performance and good electrostatic capacity; and it can be used for producing gauze windows, air conditioning filters, air purification filters and the like, and has a wide range of applications.

Provided are anti-pathogenic sintered nanoparticle compounds made of zeolite, silver nitrate (AgNO.sub.3), silver dioxide nanoparticles (Ag.sub.2O np), and graphene. Provided are enhanced granulated activated charcoal (EGAC) compounds made of granulated activated charcoal, silver nitrate (AgNO.sub.3), silver dioxide nanoparticles (Ag.sub.2O np), and graphene. Uses of the same are provided, including in enhanced filtration systems and/or pressurized wastewater filtration plants.

A gas filtering medium is composed of hydrophobic polyester fiber as from 20-80% by total weight of textile fibers and 80-20% by total weight of hydrophilic textile fibers and a microfibrillated cellulose fiber in a weight/weight ratio of 1.5-8.5/100 parts by weight of total textile fiber.

A mask with at least one filtering layer that includes a fabric made of non-conductive polymer fibers embedded with nanoparticles of two different metals is provided. The population density of the nanoparticles of the two metals on the surface of non-conductive polymer fibers is configured such that the adjacent nanoparticles of the two metals have an average distance of two micrometers or less. The two different metals are selected such that the electric field intensity generated between the nanoparticles of the two different metal through the aerosol particle inactivates the microorganisms that may be inside the aerosol particle. When an aerosol particle comes into contact with the nanoparticles of the two metals, the aerosol acts as an electrolyte between the two metal types and a potential difference and an electric field is generated, through the aerosol particle, between the nanoparticles of the two metals.

Metal nanoparticle agglomerates may convey biocidal activity to surfaces upon which they are deposited and become adhered, such as various air filtration media. Air filtration media may comprise a plurality of fibers having a plurality of metal nanoparticle agglomerates adhered thereto. The metal nanoparticle agglomerates may comprise a plurality of fused, partially fused, or unfused metal nanoparticles that are associated with one another upon a surface of the plurality of the fibers. Suitable metal nanoparticles for promoting biocidal activity against various pathogens, such as viruses and bacteria, may include copper nanoparticles and/or silver nanoparticles. Masks, inline filters, and air filtration systems may incorporate the air filtration media.

Provided is a protective mask that includes one or more layers of an air-permeable aerogel. The aerogel can be nonmetallic, metallic, metallic oxide, semi-conductive, or any combination thereof. The protective mask can include a nonmetallic interior layer and a metallic or metallic oxide exterior layer surrounding the nonmetallic interior layer. Alternatively, the facemask can include a semi-conductive layer, a power source, and a customizable switch. The pore size of the aerogel can be selected from a size ranging from <1 to 100 nanometers based on intended use. One or more layers can be incorporated into a facemask or respirator filter to protect a user from nanometric airborne particles, harmful chemicals used in industry, and the like. The filter is reusable and the pore size can be customized to deny entry to almost any size of particulate that is desired.

A method for preparing a composite filter medium (1), comprising a step of forming a first filter medium (8) through deposition of nanofibers (4) on a base fabric (2) through an electrospinning process and a step of covering said filter medium (1) by plasma deposition of a coating (7) on said first filter medium (8) in a vacuum chamber (9). According to the invention, after the electrospinning process and before the plasma deposition of the coating (7), a degassing step of the base fabric (2) and of the nanofibers (4) forming the aforementioned first filter medium (8) is provided inside the same chamber (9). With respect to the known filter media, that of the invention offers the advantage of maintaining the desired level of water and oil repellency, due to the formation of a completely polymerized coating strongly adhering to the surface of the base fabric and of the nanofibers.

A combination of nanoparticles applied onto a mask filtration system, exemplarily including 1%-10% graphene; 1%-10% titanium dioxide; 1%-10% zinc oxide; 1%-10% copper oxide; 1%-10% silicon dioxide; and balance solvent is provided.

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.