In a process for the removal of hydrogen chloride and/or sulfur oxides from a landfill gas stream, which contains impurities such as siloxanes, H.sub.2S, organic and inorganic sulfides and volatile organic compounds (VOCs), the heated gas is passed through a siloxane removal bed, where siloxanes are absorbed and then through one or more sulfur removal beds, where hydrogen sulfide and/or organic sulfides are absorbed. The effluent is passed through a reactor containing an oxidation catalyst enabling catalytic oxidation of VOCs, organic and inorganic CI- and/or S-containing compounds, COS and CS.sub.2 to their respective combustion products, and finally the effluent from the reactor is passed through one or more beds, where hydrogen chloride and/or sulfur oxides are absorbed.

The present invention provides an exhaust gas purifying composition containing BEA zeolite containing phosphorus, wherein an amount of phosphorus is such that a molar ratio thereof with respect to Al in the zeolite is 0.5 or greater, and a maintaining factor R.sub.S of a specific surface area of the exhaust gas purifying composition after heating at 980 C. for 25 hours is 35% or greater. Furthermore, the present invention also provides an exhaust gas purifying composition containing phosphorus-containing zeolite, wherein an amount of phosphorus is such that a molar ratio thereof with respect to Al in the zeolite is from 0.5 to 8, and a maintaining factor R.sub.d of a crystallite diameter after heating at 980 C. for 25 hours is 50% or greater. The exhaust gas purifying composition of the present invention has excellent HC purifiability for exhaust gas purification in internal combustion engines such as gasoline engines.

To provide a photocatalyst decomposition apparatus that can supply a liquid phase containing a substance to be decomposed by a photocatalyst and that can perform decomposition of the substance more efficiently than in the related art. A photocatalyst decomposition system according to the invention includes: a gas phase generation apparatus configured to convert a liquid phase containing a decomposition object into a gas phase; and a photocatalyst member configured to come into contact with the gas phase to decompose the decomposition object by light from a light source. The photocatalyst member includes a base material formed of a porous material and a photocatalyst layer provided on a surface of the base material.

The present invention provides an exhaust gas purifying composition containing BEA zeolite containing phosphorus, wherein an amount of phosphorus is such that a molar ratio thereof with respect to Al in the zeolite is 0.5 or greater, and a maintaining factor R.sub.S of a specific surface area of the exhaust gas purifying composition after heating at 980 C. for 25 hours is 35% or greater. Furthermore, the present invention also provides an exhaust gas purifying composition containing phosphorus-containing zeolite, wherein an amount of phosphorus is such that a molar ratio thereof with respect to Al in the zeolite is from 0.5 to 8, and a maintaining factor R.sub.d of a crystallite diameter after heating at 980 C. for 25 hours is 50% or greater. The exhaust gas purifying composition of the present invention has excellent HC purifiability for exhaust gas purification in internal combustion engines such as gasoline engines.

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.

Method for the preparation of a monolithic catalyst for the reduction of nitrogen oxides VOC and carbon monoxide in an off-gas, the catalyst comprises at least one platinum group metal, vanadium oxide, titania and optionally tungsten oxide.

The invention relates to a multitubular reactor for dehydrogenation of liquid phase alcohol dehydrogenation and a method of liquid phase alcohol dehydrogenation. Most of the alcohol dehydrogenation reaction is endothermic reaction, the reaction temperature is high and the equilibrium conversion rate is low.

Ceramic candle filter and use of the filter in the removal of particulate matter in form of soot, ash, metals and metal compounds, together with hydrocarbons and optionally nitrogen oxides being present in process off-gas or engine exhaust gas, wherein a noble metal comprising catalyst is arranged on the permeation side of the filter and/or on the dispersion side of the filter and/or within wall of the filter, said noble metal comprising catalyst contains a noble metal in an amount of between 20 and 1000 ppm/weight of the filter.

A catalytic wall-flow filter for the treatment of an exhaust gas is disclosed. The catalytic wall-flow filter comprise at least a first, a second and a third catalytic layers: the first catalytic layer extends from the inlet-end of the substrate and comprises a first SCR composition; the second catalytic layer is provided in or on the walls of the inlet channels, extending from the inlet-end of the substrate, and comprises a PGM-containing composition; the third catalytic layer is provided in or on the walls of the outlet channels, extending from the outlet-end of the substrate, and comprises a second SCR composition.

A catalyst for producing light aromatics with heavy aromatics, a method for preparing the catalyst, and a use thereof are disclosed. The catalyst comprises a carrier, component (1), and component (2), wherein component (1) comprises one metal element or more metal elements selected from a group consisting of Pt, Pd, Ir, and Rh, and component (2) comprises one metal element or more metal elements selected from a group consisting of IA group, IIA group, IIIA group, IVA group, IB group, IIB group, IIIB group, IVB group, VB group, VIB group, VIIB group, La group, and VIII group other than Pt, Pd, Ir, and Rh. The catalyst can be used for producing light aromatics with heavy aromatics, whereby heavy aromatics hydrogenation selectivity and light aromatics yield can be improved.