A filter section of a heating, ventilation, and air conditioning (HVAC) system includes a plurality of filters arranged in series relative to a flow path of air through the filter section. The plurality of filters includes at least one movable filter transformable between an extended position arranged within the flow path of air and a retracted position removed from the flow path of air. At least one movement mechanism is operably coupled to the at least one movable filter to transform the at least one movable filter between the extended position and the retracted position.

A supported catalyst for decomposing an organic substance that includes a support and a catalyst particle supported on the support. The catalyst particle contains a perovskite-type composite oxide represented by A.sub.xB.sub.yM.sub.zO.sub.w, where the A contains at least one selected from Ba and Sr, the B contains Zr, the M is at least one selected from Mn, Co, Ni and Fe, y+z=1, x≥0.995, z≤0.4, and w is a positive value satisfying electrical neutrality. A film thickness of a catalyst-supporting film supported on the support and containing the catalyst particle is 5 μm or more, or a supported amount as determined by normalizing a mass of the catalyst particle supported on the support by a volume of the support is 45 g/L or more.

A process for the purification of CO.sub.2 from chlorinated hydrocarbons and non-chlorinated hydrocarbons, comprising: contacting a CO.sub.2 stream with a chromium oxide catalyst, wherein the stream comprises the CO.sub.2, and impurities, wherein the impurities comprise the non-chlorinated hydrocarbons and the chlorinated hydrocarbons; forming a purified CO.sub.2 stream by interacting the impurities with the chromium oxide catalyst to form additional CO.sub.2 and chromium chloride; and regenerating the chromium oxide catalyst by contacting the chromium chloride with an oxygen containing gas stream.

Described is a device (1) for reducing pollutants in a gaseous mixture comprising: •a containment body (2) having an inlet portion (3) for the gaseous mixture and an outlet portion (4) for the gaseous mixture, the containment body (2) imposing on the gaseous mixture a fixed direction of flow (D), •at least one filtering unit (10) comprising a photocatalytic filter (7) interposed, along the fixed direction of flow (D), between a first light source (6a) and a second light source (6b), both having a wavelength in the visible spectrum (400-700 nm), the photocatalytic filter (7) comprising a photocatalytic nanoparticle coating and the nanoparticle coating comprising titanium dioxide doped with a nitrogen doping agent. •a unit (5) for straightening the flow before the filtering unit (10).

A compact air purification apparatus which can improve an acetaldehyde removal performance and of which the size can be reduced is provided. A compact air purification apparatus using a photocatalyst includes a housing, a photocatalyst member that is disposed in the housing and contains titanium oxides, a light emitting unit that is disposed in the housing to irradiate the photocatalyst member with ultraviolet light and includes a plurality of LED elements, and a fan that circulates air inside the housing.

One object is to provide a useful aldehyde decomposition catalyst, and an exhaust gas treatment apparatus and an exhaust gas treatment method using the aldehyde decomposition catalyst that achieve low cost and sufficient aldehyde decomposition performance with a small amount of the catalyst. An aldehyde decomposition catalyst of the present invention is made of a zeolite in a cation form NH.sub.4 having a structure of CHA or MOR and carrying Cu.

The mixing nozzle has a throat section, a diffuser section, a gas nozzle section, a first liquid suction port, a liquid nozzle section, a second liquid suction port, a baffle plate, and a jetting port. The first liquid suction port liquidly absorbs the solution in the water storage pool from a side of the gas nozzle section toward the gas nozzle tip. The liquid nozzle section extends to the downstream side of the gas nozzle section with intervening the first liquid suction port. The second liquid suction port liquidly absorbs the solution in the water storage pool from a side of the liquid nozzle section toward the liquid nozzle tip. The baffle plate is provided such that the mixed flow mixed in the diffuser section collides in front of a downstream end of the diffuser section, and divides and reverses the mixed flow.

One object is to provide an aldehyde decomposition catalyst, and an exhaust gas treatment apparatus and an exhaust gas treatment method using the aldehyde decomposition catalyst that achieve low cost and sufficient aldehyde decomposition performance with a small amount of the catalyst. An aldehyde decomposition catalyst of the present invention is made of a zeolite in a cation form NH.sub.4 having a structure selected from MFI and BEA and carrying at least one metal selected from the group consisting of Cu, Mn, Ce, Zn, Fe, and Zr.

An exhaust gas treatment device capable of treating exhaust gas of a gas turbine or a gas engine includes an exhaust gas treatment catalyst comprising a perovskite composite oxide containing at least Ag and Dy in an A site and at least Mn in a B site.

Provided herein is a device for removing residual hydrogen peroxide or hydrazine from an effluent gas stream which includes a metal oxide scrubber material configured to react with residual process gases under increased temperatures. Also provided are systems and methods of using the same.