A recyclable ceramic catalyst filter, a filtering system including the same, and a method of managing the filtering system are provided. The ceramic catalyst filter has a monolithic structure including a first surface which blocks a first material; and a second surface which removes a second material that passed through the first surface, where the second surface is activated and operates as a catalyst layer which removes the second material in response to energy supplied to the second surface.

The present disclosure provides catalyst compositions and catalytic articles capable of storing and/or reducing nitrogen oxide (NO.sub.x) emissions in engine exhaust, catalyst articles coated with such compositions, and processes for preparing such catalyst compositions and articles. The catalyst compositions include copper and palladium co-exchanged zeolites. Further provided is a process for preparing such co-exchanged zeolites, an exhaust gas treatment system including the catalytic articles disclosed herein, and methods for reducing NO in an exhaust gas stream using such catalytic articles and systems.

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.

Zeolite catalysts and systems and methods for preparing and using zeolite catalysts having the CHA crystal structure are disclosed. The catalysts can be used to remove nitrogen oxides from a gaseous medium across a broad temperature range and exhibit hydrothermal stable at high reaction temperatures. The zeolite catalysts include a zeolite carrier having a silica to alumina ratio from about 15:1 to about 256:1 and a copper to alumina ratio from about 0.25:1 to about 1:1.

A method of converting nitrogen oxides in a gas to nitrogen by contacting the nitrogen oxides with a nitrogenous reducing agent in the presence of a zeolite catalyst containing at least one transition metal, wherein the zeolite is a small pore zeolite containing a maximum ring size of eight tetrahedral atoms, wherein the at least one transition metal is selected from the group consisting of Cr, Mn, Fe, Co, Ce, Ni, Cu, Zn, Ga, Mo, Ru, Rh, Pd, Ag, In, Sn, Re, Ir and Pt.

Disclosed are an extruded honeycomb catalyst, a process for preparing the catalyst, a method for reducing NOx in the exhaust gas from an internal combustion engine by using the catalyst, and a method for treatment of the emission gas generated from power plant comprising exposing the emission gas to the catalyst.

Systems and methods use bimetallic alloy particles for converting hydrogen sulfide (H.sub.2S) to hydrogen (H.sub.2) and sulfur (S), typically during multiple operations. In a first operation, metal alloy composite particles can be converted to a composite metal sulfide. In a second operation, composite metal sulfide from the first operation can be regenerated back to the metal alloy composite particle using an inert gas stream. Pure, or substantially pure, sulfur can also be generated during the second operation.

Processes, systems, and associated control methodologies are disclosed that control the flow of biogas during the biogas cleanup process to create a more consistent flow of biogas through the digester, while also optimizing the output and efficiency of the overall renewable natural gas facility. In representative embodiments, a biogas buffer storage system may be used during the cleanup process to control the pressure and flow rate of biogas. The biogas buffer storage system may monitor and control the biogas flow rate to either bring down or increase the digester pressure, thereby maintaining a normalized biogas flow rate.

The invention relates to an aerogel concrete mixture containing a photocatalyst, a photocatalytically active high-performance aerogel concrete obtainable therefrom and a method for producing same.

Methods and compositions related to a selective catalytic reduction catalyst comprising iron and vanadium, wherein the vanadium is present as (1) one or more vanadium oxides, and (2) metal vanadate of the form Fe.sub.xM.sub.yVO.sub.4 where x=0.2 to 1 and y=1−x, and where M comprises one or more non-Fe metals when y>0.