Abstract: A catalyst for catalytic reduction of nitrogen oxide using at least one reducing agent selected from the group consisting of a hydrocarbon and an oxygen-containing organic compound is described, which includes an oxide represented by formula (V):A.sup.5.sub.x B.sup.3.sub.3-x C.sup.4.sub.3 O.sub.7 (V)wherein A.sup.5 represents at least one element selected from the group consisting of La, Y, Ce, Pr, Nd, Sm, Eu, and Gd; B.sup.3 represents at least one element selected from the group consisting of Ba, Sr, Ca, Mg, Pb, Zn, and Ag; C.sup.4 represents at least one element selected from the group consisting of Mn, Co, Fe, Ni, Cr, Cu, V, Mo, W, Ti, Zr, Nb, Pd, Rh, Ru, and Pt; and x is a number of from 0 to 1, supported on a solid acid carrier.

Abstract: A TiO.sub.2 containing catalyst for denitrizing nitrogen oxides in the presence of a hydrocarbon as a reducing agent is disclosed. There are also disclosed denitrizing catalysts which contain zeolite or perovskite structure complex compound.

Abstract: A catalyst for ozone decomposition which comprises:(a) at least one selected from the group consisting of clay and carbon;(b) manganese dioxide; and optionally(c) titanium dioxide; and/or(d) at least one oxide of a metal selected from the group consisting of Cu, Co, Fe, Ni and Ag.A further catalyst for ozone decomposition which comprises:(a) at least one oxide of a metal selected from the group consisting of alkali metals and alkaline earth metals;(b) manganese dioxide; and optionally(c) titanium dioxide; and/or(d) at least one selected from the group consisting of clay and carbon.

Abstract: Regeneration of an ozone decomposing reactor which comprises:a catalyst structure composed of a carrier having at least one passage extending therethrough for allowing an ozone containing fluid to pass through the catalyst structure and a catalyst and an electroconductive material carried in or on the carrier; andelectrodes attached to the catalyst structure to electrify the structure, whereby to decompose ozone at elevated temperatures and regenerating deactivated structure by electrifying and heating.The carrier is either a ceramic honeycomb mold or a fiber board.

Abstract: A process for removing nitrogen oxides from an exhaust gas by bringing the exhaust gas containing nitrogen oxides into contact with at least one catalyst selected from a polyvalent metal phosphate, a polyvalent metal sulfate or an aluminate of a transition metal of the 4th period of the Periodic Table in an oxidizing atmosphere containing excess oxygen and in the presence of a hydrocarbon or an oxygen containing organic compound. There is also disclosed a process for removing nitrogen oxides from an exhaust gas which comprises bringing the exhaust gas into contact with the above catalyst and then with an oxidation catalyst.

Abstract: A catalyst for ozone decomposition which comprises:(a) at least one selected from the group consisting of clay and carbon;(b) manganese dioxide; and optionally(c) titanium dioxide; and/or(d) at least one oxide of a metal selected from the group consisting of Cu, Co, Fe, Ni and Ag.A further catalyst for ozone decomposition which comprises:(a) at least one oxide of a metal selected from the group consisting of alkali metals and alkaline earth metals;(b) manganese dioxide; and optionally(c) titanium dioxide; and/or(d) at least one selected from the group consisting of clay and carbon.

Abstract: The present invention provides a deodorizing method for removing malodorant components by oxidative destruction with ozone in the presence of a catalyst comprising a first component, which is a metal oxide, and a second component which is at least one member selected from the group consisting of titanium dioxide, silver oxide, silica and gold, or a catalyst comprising manganese dioxide and clay.Also, the present invention provides a deodorizing catalyst having its active components carried in a layer, having a thickness of 10 to 200 .mu.m, on the carrier, thereby stably removing malodorant components at a high rate, even when the reaction conditions are changed.

Abstract: A catalyst for decomposing ozone comprising a carrier and a catalytic active substance having ozone resolvability carried thereon in a thickness of 10 to 200 .mu.m. Consequently, ozone can efficiently be removed. The invention also includes the catalytic active substance or ozone adsorption substance which is contained in the carrier, such that the combination of the carrier and its contained material has ozone resolvability or ozone adsorbing ability in itself. Accordingly, the combination of these two features allows the thickness of the catalytic active substance carried on a carrier surface to be reduced to the range from 5 to 100 .mu.m. Thus, improved productivity, durability of the catalyst and ozone removing efficiency are provided.

Abstract: The present invention provides an exhaust gas treating method by which exhaust gas is passed through a catalyst layer at an areal velocity of 100 to 5000 m.sup.3 /m.sup.2 .multidot.hr to selectively produce carbon monoxide from particulates contained in the exhaust gas, so that nitrogen oxides contained in the exhaust gas are removed by the carbon monoxide thus produced. The exhaust gas treating method of the present invention can readily and securely remove particulates and nitrogen oxides contained in exhaust gas, i.e., two primary causes of air pollution, by merely passing the exhaust gas through a catalyst layer at a specific areal velocity.

Abstract: A denitrizing catalyst with comprises:(a) a zeolite represented by the general formula (I)H.sub.A M.sub.B [(AlO.sub.2).sub.X .multidot.(SiO.sub.2).sub.Y ].multidot.2H.sub.2 0wherein M is an alkali metal or an alkaline earth metal, and A+nB=X wherein n is a valency of the metal M, in amounts of 80-99.9% by weight; and(b) at least one metal or at least one oxide of metals selected from the group consisting of Ru, Rh, Pd, Ag, Pt, Au, Co, Cu, Cr and Ni, in amounts of 0.1-20% by weight.A further denitrizing catalyst which comprises a zeolite represented by the general formulaH.sub.A (M.sup.1).sub.B (M.sup.2).sub.c [(AlO.sub.2).sub.X .multidot.(SiO.sub.2).sub.Y ].multidot.2H.sub.Z Owherein M.sup.1 is an alkali metal or an alkaline earth metal, M.sup.2 is a metal selected from the group consisting of Ru, Rh, Pd, Ag, Pt, Au, Co, Cu, Cr and Ni, A+n.sub.1 B+n.sub.2 C=X wherein n.sub.1 and n.sub.2 are valecies of the metals M.sup.1 and M.sup.2, respectively.

Abstract: There is provided a method of producing titanium oxides which comprises: admixing an aqueous solution of titanium tetrachloride with sulfuric acid in a molar ratio of sulfuric acid to titanium tetrachloride of at least 0.5 adding an alklai to the resultant solution to produce titanium hydroxide; and drying and calcining the titanium hydroxide. A further method is provided which comprises: adding a solution of an alkali to an aqueous solution of titanium tetrachloride having a concentration of not more than 2.5 moles/l at temperatures of not less than 50.degree. C., thereby to substantially thermally hydrolyze the titanium tetrachloride and to produce titanium hydroxide; and drying and calcining the titanium hydroxide.

Abstract: The present invention relates to a particulate removing catalyst filter in which an oxidizing catalyst is carried on the surface portions of an air-permeable substrate to a depth, based on the substrate and the catalyst, of up to 19% measured from the exposed surface of the catalyst through which the exhaust gas is adapted to be passed, and to a particulate removing catalyst filter in which a catalyst is carried on a thin wire net or metallic plate having a plurality of fine through-holes. The exhaust gas from a diesel engine is forcibly passed through the filter, thereby to remove particulates in the exhaust gas.

Abstract: There is disclosed an ozone decomposing reactor which comprises:a catalyst structure composed of a carrier having at least one passage extending therethrough for allowing an ozone containing fluid to pass through the catalyst structure and a catalyst and an electroconductive material carried in or on the carrier; andelectrodes attached to the catalyst structure to electrify the structure, whereby to decompose ozone at elevated temperatures.The carrier is either a ceramic honeycomb mold or a fiber board.

Abstract: There is disclosed an ozone decomposing reactor which comprises:an air permeable carrier containing a catalyst and an electroconductive material therein or thereon; andelectrodes attached to the sheet to electrify and heat the sheet, whereby to decompose ozone at elevated temperatures.A fibrous sheet or a foamed material is used as the air permeable carrier.

Abstract: A denitrizing catalyst which comprises:(a) an alkali metal oxide or an alkaline earth metal oxide in amounts of 50-90% by weight as oxides;(b) at least one metal oxide selected from the group consisting of Co.sub.3 O.sub.4, Cu.sub.2 O, Cr.sub.2 O.sub.3, Mn.sub.2 O.sub.3, NiO, PbO, Bi.sub.2 O.sub.3, MoO.sub.2, Al.sub.2 O.sub.3, SiO.sub.2, ZrO.sub.2, Fe.sub.2 O.sub.3, TiO.sub.2, WO.sub.3, MoO.sub.3, SnO.sub.2 and ZnO in amounts of 5-50% by weight as oxides; and(c) at least one metal or at least one oxide of metals selected from the group consisting of Ru, Rh, Pd, Ag, Pt and Au in amounts of 0.01-10% by weight as metals.Nitrogen oxides contained in waste gases are denitrized effectively by putting the gases into contact with the catalysts in the absence or presence of carbon monoxide as a reducing agent.

Abstract: A denitrizing catalyst which comprises:(a) an alkali metal oxide or an alkaline earth metal oxide in amounts of 50-90% by weight as oxides;(b) at least one metal oxide selected from the group consisting of Co.sub.3 O.sub.4, Cu.sub.2 O, Cr.sub.2 O.sub.3, Mn.sub.2 O.sub.3, NiO, PbO, Bi.sub.2 O.sub.3, MoO.sub.2, Al.sub.2 O.sub.3, SiO.sub.2, ZrO.sub.2, Fe.sub.2 O.sub.3, TiO.sub.2, WO.sub.3, MoO.sub.3, SnO.sub.2 and ZnO in amounts of 5-50% by weight as oxides; and(c) at least one metal or at least one oxide of metals selected from the group consisting of Ru, Rh, Pd, Ag, Pt and Au in amounts of 0.01-10% by weight as metals.Nitrogen oxides contained in waste gases are denitrized effectively by putting the gases into contact with the catalysts in the absence or presence of carbon monoxide as a reducing agent.

Abstract: There is provided a method of producing titanium-oxides which comprises: admixing an aqueous solution of titanium tetrachloride with sulfuric acid in amounts of at least 0.5 times is moles as the titanium tetrachloride; adding an alkali to the resultant solution to produce titanium hydroxide; and drying and calcining the titanium hydroxide. A further method is provided which comprises: adding a solution of an alkali to an aqueous solution of titanium tetrachloride having a concentration of not more than 2.5 moles/l at temperatures of not less than 50.degree. C., thereby to substantially thermally hydrolyze the titanium tetrachloride and to produce titanium hydroxide; and drying and calcining the titanium hydroxide.

Abstract: A catalyst for ozone decomposition which comprises: at least one oxide of a metal selected from the group consisting of Cu, Mn, Co, Fe and Ni; and at least one oxide of a metal selected from the group consisting of Ti and Ag, and/or Au.A further catalyst freed from deterioration in activity even when it is used under severe conditions, which comprises: a ternary metal oxide represented by the formula of xMnO.sub.z.yAg.sub.z O.zTiO.sub.z wherein weight proportion coordinates (x, y, z) of the oxide on a triangular diagram are either on sides of a triangle formed by connecting three points (20, 10, 70), (80, 10, 10) and (20, 70, 10) with straight lines or within the traingle, as seen in FIG. 1.

Abstract: A method of producing ceramic honeycomb structures which comprises: the first step of preparing a ceramic plastic composition which comprises admixing and kneading a ceramic material with water, a polyalkylene glycol monoether and an organic binder; the second step of extruding the ceramic plastic composition into a wet green mold of a honeycomb structure having openings extending therethrough; the third step of passing a high humidity air through the openings to evaporate the substantial amount of the water in the green mold; the fourth step of passing heated air to evaporate the substantial amount of the polyalkylene glycol monoether from the green mold; and the fifth step of calcining the mold.The method is suitably applicable to the production of ceramic honeycomb structures as a catalyst structure or a catalyst carrier structure therefor which contains a material acting as an oxidation catalyst.

Abstract: A catalyst for denitrizing nitrogen oxides contained in waste gases in the presence of arsenic compounds, which comprises: titanium and vanadium therein in weight ratios of oxides of titanium to oxides of vanadium ranging from 99.9:0.1 to 92.0:8.0, the vanadium being concentratedly contained in the surface layer of the catalyst up to 200 .mu.m in depth from the surface of the catalyst in concentrations of at least about 1.5 times as much as the concentrations of vanadium throughout the catalyst.The catalyst may further contain therein at least one of tungsten and zirconium.The catalyst preferably has micropores of about not less than about 50 .ANG. in amounts of 0.25-0.40 ml/g, and micropores of about 50-100 .ANG. in radius in amounts of about 10-40% by volume and micropores of about 1000-60000 .ANG. in radius in amounts of not less than about 10% by volume, respectively, based on the total volume of the micropores of not less than about 50.ANG. in radius.