Disclosed is method for removing carbonyl sulphide and/or carbon disulphide from a sour gas stream. The method comprises subjecting the gas stream to simultaneous contact with an absorption liquid, such as an aqueous amine solution, and with a catalyst suitable for hydrolyzing carbonyl sulphide and/or carbon disulphide. To this end, the invention also provides a reactor system wherein both an absorption liquid and a catalyst are present. In a preferred embodiment, the catalyst is a heterogeneous catalyst present on or in an absorption column, either coated on the trays of a column with trays, or contained in the packing of a packed column.

Provided is a catalyst including: a support including titanium oxide; an active catalyst component including vanadium oxide; and a co-catalyst including antimony and cerium, in which the catalyst is included in a deNox reduction reaction that decomposes nitrogen oxide. The catalyst may improve sulfur poisoning tolerance characteristics while improving the deNox efficiency at a temperature in a wide range from low temperature to high temperature.

Provided is a catalyst including: a support including titanium oxide; an active catalyst component including vanadium oxide; and a co-catalyst including antimony and cerium, in which the catalyst is included in a deNox reduction reaction that decomposes nitrogen oxide. The catalyst may improve sulfur poisoning tolerance characteristics while improving the deNox efficiency at a temperature in a wide range from low temperature to high temperature.

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.

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.

The invention provides a method of reducing the amount of nitrogen oxide components in a process gas stream comprising: a) contacting a deNO.sub.X catalyst with the process gas in the presence of ammonia which results in the conversion of nitrogen oxide components as well as a decline in the NO.sub.X conversion over the deNO.sub.X catalyst; and b) regenerating the deNO.sub.X catalyst to improve the NO.sub.X conversion by contacting the deNO.sub.X catalyst at a temperature in the range of from 250 to 390 C. with a flow of ammonia that is reduced relative to the flow of ammonia in step a) and process gas, air or a mixture thereof.

The invention provides a method of reducing the amount of nitrogen oxide components in a process gas stream comprising: a) contacting a deNO.sub.X catalyst with the process gas in the presence of ammonia which results in the conversion of nitrogen oxide components as well as a decline in the NO.sub.X conversion over the deNO.sub.X catalyst; and b) regenerating the deNO.sub.X catalyst to improve the NO.sub.X conversion by contacting the deNO.sub.X catalyst at a temperature in the range of from 250 to 390 C. with a flow of ammonia that is reduced relative to the flow of ammonia in step a) and process gas, air or a mixture thereof.

Photocatalytic materials with a composite photocatalyst of a metal oxide impregnated with elemental metal particles, can be embedded into a hydrophilic polymer having pores with diameters of less than 2 nm, to provide a useful water remediation and/or purification product. The metal oxide may be WO.sub.3, CeO.sub.2, Bi.sub.2O.sub.3, NiO, TiO.sub.2, and/or ZnO, and the elemental metal particles, impregnated or compounded into the metal oxide, may be Fe, Co, Ni, Cu, Ag, Ce, Mn, Mo, V, Bi, Sn, W, Nb, Pd, and/or Pt. The photocatalytic materials may be easily removed and/or retrieved after use, and can effectively combat both chemical and biological contamination and/or fouling of water as well as the membranes composed of the photocatalytic material.

Photocatalytic materials with a composite photocatalyst of a metal oxide impregnated with elemental metal particles, can be embedded into a hydrophilic polymer having pores with diameters of less than 2 nm, to provide a useful water remediation and/or purification product. The metal oxide may be WO.sub.3, CeO.sub.2, Bi.sub.2O.sub.3, NiO, TiO.sub.2, and/or ZnO, and the elemental metal particles, impregnated or compounded into the metal oxide, may be Fe, Co, Ni, Cu, Ag, Ce, Mn, Mo, V, Bi, Sn, W, Nb, Pd, and/or Pt. The photocatalytic materials may be easily removed and/or retrieved after use, and can effectively combat both chemical and biological contamination and/or fouling of water as well as the membranes composed of the photocatalytic material.

A process for the cleaning of a lean gas stream contaminated with volatile organic compounds (VOCs) and/or sulfur-containing compounds comprises the steps of adding ozone to the contaminated lean gas stream, subjecting the ozone-containing lean gas stream to ultraviolet irradiation, thereby transforming VOCs to particles, maintaining the irradiated gas stream in a stay zone for a sufficient time to allow aerosol particle growth, and passing the gas stream through a catalytic bag filter at a temperature down to room temperature to remove the formed particles and eliminate any remaining ozone. The bag filter has been made catalytic by impregnation with one or more metal oxides in which the metals are selected from V, W, Pd and Pt, supported on TiO.sub.2.