An electronic microbicidal air filter is provided as an ambient air filter in aeration supports or ventilation grids and as an air filter for PPE protection masks. The filter includes an UVC luminaire (2), a power module (3), activation sensors (4), internal structure (5) with walls defining filtering chambers (6) with exposure membranes (7) sandwiched between the chambers (6) under the luminaire (2), so that the chambers (6) determine a winding zigzag path for the air that passes therethrough, while the particles carried by the air are irradiated by the luminaire (2) directly. The functional elements in the internal structure (5) of chambers (6) are integrated in an encapsulation (9) that surrounds the external part of the assembly and defines a sealed space for the functional and support elements at the ends of the structure (5).

Filter media comprising a pre-filter layer and related components, systems, and methods associated therewith are provided. In some embodiments, the pre-filter layer may be designed to impart desirable properties to the filter media, such as a high gamma and/or long service life, while having relatively minimal or no adverse effects on another property of the filter media that is important for a given application. For instance, a pre-filter layer may be used to improve the upstream removal of fine particulate matter, which may clog a downstream efficiency layer comprising submicron fibers and reduce filtration performance. The pre-filter layer may be configured to increase service life and/or increase the gamma of the filter media. Filter media, as described herein, may be particularly well-suited for applications that involve filtering air, though the media may also be used in other applications.

An air filter medium includes a first porous PTFE membrane and a second porous PTFE membrane. The air filter medium (10) has a first main surface and a second main surface, and the first porous PTFE membrane and the second porous PTFE membrane are arranged so that an air flow moving from the first main surface to the second main surface passes through the first porous PTFE membrane and subsequently through the second porous PTFE membrane. A thickness of the first porous PTFE membrane is in the range of 4 to 40 μm and a specific surface area of the first porous PTFE membrane is 0.5 m.sup.2/g or less.

A filter may remove PM.sub.2.5 and/or other airborne pollutants, which filter has fibers of an average diameter of no more than 500 nm, the fibers of at least 90 wt. % polyacrylonitrile, relative to all fibers in the filter; and a catalyst of at least 90 wt. % TiO.sub.2, relative to all catalytic metals in the filter, dispersed onto the fibers. The fibers need not be charged. The TiO.sub.2 may be condensed or precipitated onto the fibers out of a liquid containing the TiO.sub.2 and the fibers by simple methods. The catalyst may be activated by UV irradiation to decompose particulate matter having an average particle size of 2.5 μm or less, i.e., PM.sub.2.5, and/or other airborne pollutants from air. Such filters may be implemented around areas of vehicle traffic, e.g., as elements of traffic lights, and may be used to controllably purify polluted air.

Included are methods and systems for recycling a gas emitted from non-aqueous cleaning. An example method includes contacting a contaminated equipment with a non-aqueous cleaning material; wherein the spent non-aqueous cleaning material emits the gas. The method further comprises capturing the emitted gas, filtering the emitted gas, and recycling the emitted gas into the non-aqueous cleaning material.

An ambient air purification device has a filter device arranged in a filter receiving region of its housing. The filter device has a main filter element and a prefilter element, each having a circumferential frame device. A clamping force generating device is provided in the housing to exert an axial clamping force on the frame device of the main filter element resting, when mounted, at the frame device of the prefilter element. The clamping force is transmitted to the frame device of the prefilter element and presses the latter seal-tightly via a seal against a circumferential contact shoulder of the filter receiving region to seal the filter device in the filter receiving region. The frame device of the main filter element is sealed indirectly by the frame device of the prefilter element in relation to the housing and has no seal location of its own in relation to the housing.

Filter media and filters, such as air filters, face masks, gas turbine and compressor air intake filters, panel filters and the like, are provided that include nanoparticles dispersed throughout at least a portion of the filter media. A filter media comprises a fiber substrate with a first surface and an opposing second surface. The filter media includes nanoparticles disposed within the fiber substrate at least between the first and second surfaces such that an area density of the nanoparticles decreases from the first surface towards the second surface. This density gradient formed by the nanoparticles through at least a portion of the substrate improves the performance characteristics of the filter. The nanoparticles increase the overall surface area within the fiber substrate, which may increase its filtration efficiency and allows for the capture of submicron contaminants without significantly compromising other factors, such as pressure drop or air flow through the filter.

A nanofiber filter includes: a first support having a front surface and a rear surface opposite to the front surface; a first nanofiber filter layer disposed on the rear surface of the first support; a second nanofiber filter layer disposed on a rear surface of the first nanofiber filter layer; a third nanofiber filter layer disposed on a rear surface of the second nanofiber filter layer; and a second support disposed on a rear surface of the third nanofiber filter layer.

Disclosed herein are filtration articles comprising a porous ceramic structure comprising a plurality of channels separated by a plurality of porous interior walls, and a nanomembrane disposed on at least a portion of a surface of the porous ceramic structure, wherein the nanomembrane comprises nanoparticles of at least one inorganic oxide, and wherein the nanoparticles are present in a concentration ranging from about 0.001 g/L to about 1 g/L based on the total volume of the porous ceramic structure. Methods for making such filtration articles and methods for filtering a particulate from a fluid using such filtration articles are also disclosed herein.

Described here is an air filter comprising a substrate and a network of polymeric nanofibers deposited on the substrate, wherein the air filter a removal efficiency for PM.sub.2.5 of at least 70% when a light transmittance is below 50%. Also described here is an electric air filter comprising a first layer adapted to receive a first electric voltage, wherein the first layer comprises an organic fiber coated with a conductive material. Further described is an air filter for high temperature filtration, comprising a substrate and a network of polymeric nanofibers deposited on the substrate, wherein the air filter has a removal efficiency for PM.sub.2.5 of at least 70% at a temperature of a least 70° C.