Some embodiments of the present disclosure relate to a method of regenerating at least one filter medium comprising: providing at least one filter medium, wherein the at least one filter medium comprises: at least one catalyst material; and ammonium bisulfate (ABS) deposits, ammonium sulfate (AS) deposits, or any combination thereof; flowing a flue gas stream transverse to a cross-section of a filter medium, such that the flue gas stream passes through the cross section of the at least one filter medium, wherein the flue gas stream comprises: NOx compounds comprising: Nitric Oxide (NO), and Nitrogen Dioxide (NO.sub.2); and increasing an NOx removal efficiency of the at least one filter medium after removal of deposits.

Disclosed in certain embodiments is a sulfur tolerant catalytic system that includes a catalytic material coated onto a substrate. Certain embodiments are directed to a method of preparing a sulfur-tolerant catalyst.

Provided are: a complex oxide that exhibits high redox ability even at low temperatures, has excellent heat resistance, and stably retains these characteristics even on repeated oxidation and reduction at high temperature; a method for producing the same; and an exhaust gas purification catalyst. The inventive complex oxide contains more than 0 but no more than 20 parts by mass of Si, calculated as SiO.sub.2, per total 100 parts by mass of rare earth metal elements including Ce, calculated as oxides; and has a characteristic such that when it is subjected to temperature-programmed reduction (TPR) measurement in a 10% hydrogen-90% argon atmosphere at from 50° C. to 900° C. with the temperature increasing at a rate of 10° C./min, followed by oxidation treatment at 500° C. for 0.5 hours, and then temperature-programmed reduction measurement is performed again, its calculated reduction rate at and below 400° C. is at least 1.5%.

A filter includes a filter medium having an average pore size of 1 to 5 mm, and photocatalyst particles deposited on the filter medium. The photocatalyst particle contains a titanium compound particle and a metal compound bonded to the surface of the titanium compound particle with an oxygen atom. The metal compound contains a metal atom and a hydrocarbon group. The titanium compound particle has absorption at wavelengths of 450 nm and 750 nm in the visible absorption spectrum of the titanium compound particle.

The present application relates to a process for treating the off gas from a carbon black process, said process comprising the steps of: providing an off gas from a carbon black process, reacting said off gas in a first reaction step forming water and S, and condensing the S at a temperature Tcon where S is in a liquid phase and the water is in gas form thereby achieving a gaseous stream comprising water and a liquid stream comprising S, and wherein the first reaction step is carried out over a monolith catalyst.

A catalyst article including a substrate with an inlet side and an outlet side, a first zone and a second zone, where the first zone includes a passive NOx adsorber (PNA), and an ammonia slip catalyst (ASC) comprising a platinum group metal on a support and a first SCR catalyst; where the second zone includes a catalyst selected from the group consisting of a diesel oxidation catalyst (DOC) and a diesel exotherm catalyst (DEC); and where the first zone is located upstream of the second zone. The first zone may include a bottom layer with a blend of: (1) the platinum group metal on a support and (2) the first SCR catalyst; and a top layer with a second SCR catalyst, the top layer located over the bottom layer.

A method of reducing NO.sub.x in tail gas obtained during startup of a plant for preparing nitric acid may involve heating the tail gas from a starting temperature T.sub.0, through a threshold temperature T.sub.G, to an operating temperature T.sub.B at which steady-state operation of the plant can occur (T.sub.0<T.sub.G<T.sub.B). NO.sub.x-containing tail gas may be passed through a storage medium and at least partially stored while the temperature of the tail gas is lower than the threshold temperature T.sub.G. The NO.sub.x may be released, preferably when the temperature of the tail gas has attained the threshold temperature T.sub.G. The NO.sub.x may be combined with a reducing agent in the presence of an SCR catalyst after the temperature of the tail gas has exceeded the threshold temperature T.sub.G, but not before, resulting in catalytic reduction of at least a portion of the NO.sub.x.

Method for treating a gaseous feedstock containing molecular oxygen and one or more volatile compounds, which method comprises the following steps: a) bringing said gaseous feedstock containing molecular oxygen and one or more volatile organic compounds into contact with a monolith comprising silica and titanium dioxide, said monolith comprising a type-I macropore volume, of which the diameter of the pores is greater than 50 nm and less than or equal to 1000 nm, of between from 0.1 to 3 ml/g, and a type-II macropore volume, of which the diameter of the pores is greater than 1 μm and less than or equal to 10 μm, of between from 1 to 8 ml/g; b) irradiating said monolith with at least one irradiation source producing at least one wavelength lower than 400 nm in order to convert said volatile organic compounds into carbon dioxide, said step b) being carried out at a temperature between −30° C. and +200° C. and at a pressure between 0.01 MPa and 70 MPa.

The invention relates to a photocatalytic carbon dioxide reduction method carried out in liquid and/or gas phase under irradiation, using a photocatalyst containing a first semiconductor, particles comprising one or more metallic-state elements M, and a second semiconductor SC, wherein the method is carried out by contacting a feedstock containing the CO.sub.2 and at least one sacrificial compound with the photocatalyst, then irradiating the photocatalyst such that the CO.sub.2 is reduced, and oxidising the sacrificial compound in order to produce an effluent containing at least in part C1 or above carbon molecules other than CO.sub.2.

A NO.sub.x absorber catalyst for treating an exhaust gas from a diesel engine. The NO.sub.x absorber catalyst comprises a first NO.sub.x absorber material comprising a molecular sieve catalyst, wherein the molecular sieve catalyst comprises a noble metal and a molecular sieve, and wherein the molecular sieve contains the noble metal; a second NO.sub.x absorber material comprising palladium (Pd) supported on an oxide of cerium; and a substrate having an inlet end and an outlet end.