Dry-scrubbing media compositions, methods of preparation and methods of use are provided. The compositions contain activated alumina and magnesium oxide. Optionally, activated carbon and other impregnates, such as hydroxides of group 1A metals, are included. The compositions exhibit improved efficiency and capacity for the removal of compounds, such as hydrogen sulfide, from an air-stream. The compositions are particularly useful for reducing or preventing the release of toxic gaseous compounds from the areas such as landfills, petroleum storage areas, refineries, drinking water systems, sewage treatment facilities, swimming pools, hospital morgues, animal rooms, and pulp and paper production sites.

The present invention relates to a process for the treatment of a gas stream containing nitrogen oxides comprising the steps of: (1) providing a gas stream containing one or more nitrogen oxides; (2) contacting the gas stream provided in step (1) with a transition metal containing zeolitic material having a BEA-type framework structure for reacting one or more of the nitrogen oxides; wherein the zeolitic material is obtainable from an organotemplate-free synthetic process, as well as to an apparatus for the treatment of a gas stream comprising containing nitrogen oxides.

A process for the removal of nitrous oxide (N.sub.2O) contained in a process off-gas in an axial flow reactor. The process includes the steps of (a) adding an amount of reducing agent into the process off-gas; (b) in a first stage passing in axial flow direction the process off-gas admixed with the reducing agent through a first monolithic shaped catalyst active in decomposing nitrous oxide by reaction with the reducing agent to provide a gas with a reduced amount of nitrous oxide and residual amounts of reducing agent; and (c) in a second stage passing the gas with a reduced amount of nitrous oxide and residual amounts of the reducing agent in axial flow direction through a second monolithic shaped catalyst active in oxidation of the residual amounts of the reducing agent.

Disclosed herein are catalyst compositions for removing formaldehyde, volatile organic compounds, and other pollutants from an air flow stream. In one embodiment, a catalyst composition comprises manganese oxide particles and rare earth metal catalyst particles.

Described is a process for the treatment of a gas stream containing nitrogen oxides. The process comprises the steps of: (1) providing a gas stream containing one or more nitrogen oxides; (2) contacting the gas stream provided in step (1) with a transition metal containing zeolitic material having a BEA-type framework structure for reacting one or more of the nitrogen oxides; wherein the zeolitic material is obtainable from an organotemplate-free synthetic process. Also described is an apparatus for the treatment of a gas stream comprising containing nitrogen oxides.

Described is a selective catalytic reduction material comprising a spherical particle including an agglomeration of crystals of a molecular sieve. The catalyst is a crystalline material that is effective to catalyze the selective catalytic reduction of nitrogen oxides in the presence of a reductant at temperatures between 200 C. and 600 C. A method for selectively reducing nitrogen oxides and an exhaust gas treatment system are also described.

An apparatus (1) for supplying a gas mixture to a patient, having a gas inlet line (30) with a gas inlet orifice (30a) that splits into a first gas line (31) and a second gas line (32); at least one permeation module (33) arranged on the second gas line (32), the said permeation module (33) having a feed port (33a) in fluidic communication with the second gas line (32), a retentate port (33b) and a permeate port (33c); a third gas line (34) in fluidic communication with the retentate port (33b) of the permeation module (33); a fourth gas line (35) in fluidic communication with the permeate port (33c) of the permeation module (33), and coupling fluidically to the said first gas line (31); and a source (360) of air in fluidic communication with the first gas line (31) and the fourth gas line (35).

Disclosed herein are base metal catalyst devices for removing ozone, volatile organic compounds, and other pollutants from an air flow stream. A catalyst device includes a housing, a solid substrate disposed within the housing, and a catalyst layer disposed on the substrate. The catalyst layer includes a first base metal catalyst at a first mass percent, a second base metal catalyst at a second mass percent, and a support material impregnated with at least one of the first base metal catalyst or the second base metal catalyst.

A nitric acid production process, comprising tertiary abatement of N2O and NOx on a tail gas withdrawn from an absorption stage, said abatement including passing the tail gas over a sequence of a deN2O stage comprising a Fe-z catalyst and a deNOx stage comprising a V2O5-TiO2 catalyst in the presence of gaseous ammonia, wherein the tail gas at the inlet of deN2O stage and the tail gas at the inlet of deNOx stage have a temperature greater than 400 C.

A novel method and device for the destruction of nitrous oxide in gases such as those resulting from exhaled breath during dental, medical, and veterinary procedures are described. The method employs processing steps including the collection of gases containing constituents such as water vapor, carbon dioxide, oxygen, nitrogen, and nitrous oxide from exhaled breath or from ambient room air, optional removal of moisture from the collected gas, catalytic decomposition of nitrous oxide gas to nitrogen and oxygen, heat exchange to reduce high temperatures in gases exiting the reactor, and sorbents to remove traces of reaction byproducts. Instrumentation and controls are employed to monitor and regulate temperatures, pressures, gas compositions, and flow rates while also providing measures to automatically shut down in the event of off-nominal conditions. The method and device are capable of operating with variable anesthetic or patient exhaled breath flow rates while inducing no significant pressure or vacuum on the patient as they exhale. The method is carried out in a compact device suitable for operation in dental offices, hospitals, and other locations where nitrous oxide is administered as an anesthetic.