Provided is a combustion system using a catalyst having better denitration efficiency at low temperatures, during a selective catalytic reduction reaction in which ammonia is used as a reducing agent.

This combustion system comprises: a combustion device that combusts fuel; an exhaust path through which flows exhaust gas generated from the combustion of fuel in the combustion device; a dust collection device that is arranged on the exhaust path and collects soot/dust in the exhaust gas; and a denitration device that is arranged on the exhaust path and removes nitrogen oxides from the exhaust gas by means of a denitration catalyst, wherein the denitration device is arranged downstream of the dust collection device on the exhaust path, and the denitration catalyst contains vanadium oxide, has a carbon content of 0.05 wt % or more, and has a defect site in which oxygen deficiency occurs in a crystal structure.

The invention relates to a composition for mineralising carbon dioxide and nitrogen oxide gases, which comprises a mixture of magnesium (between 1 and 25%), iron (between 1 and 23%), calcium monoxide (between 1 and 25%), titanium dioxide (between 0.1 and 11%) and silicon dioxide (between 16 and 75%), with a particle diameter between 100 nm and 4000 μm. The composition causes the mineralisation of carbon dioxide (CO.sub.2) and of the gaseous chemical compounds known as “nitrogen oxides” (NO.sub.x) in the atmosphere. This composition can be added or mixed as an additive in paints, dyes, resins and elastic polymers (gum and natural rubber) in parts with wear, and for any type of covering.

The present invention discloses a method of preparing a catalyst for low-temperature synergistic catalytic purification of NO.sub.x and HCN in a flue gas, and the use thereof. Citric acid is dissolved in ethanol to obtain a citric acid/ethanol solution; tetrabutyl titanate is added, mixed uniformly to obtain a tetrabutyl titanate-citric acid/ethanol solution; glacial acetic acid is added dropwise to react for 30-40 min to obtain a solution A; the metal salt solution was added dropwise into the solution A, mixed uniformly and added with nitric acid, ammonium hydroxide is added dropwise to adjust the pH value, and the temperature is raised at a constant speed to obtain a gel B; dried and then then baked at a temperature of 300-500° C. for 3-4 h, cooled in the furnace, pulverized, tableted and sieved to obtain the catalyst for the low-temperature synergistic catalytic purification of NO.sub.x and HCN in the flue gas.

Method for reducing the content of nitrogen oxides NOx and nitrous oxide N2O in an input gas, comprising the steps of: treating said gas with a first amount of a NOx reducing agent in a first de-NOx catalytic bed; treating the effluent of said first de-NOx catalytic bed in at least one de-N2O catalytic bed for removal of N2O; treating the effluent of said at least one de-N2O catalytic bed with a second amount of a NOx reducing agent in a second de-NOx catalytic bed.

Visible-light response hybrid aerogel and a preparation method and application thereof in waste gas processing are disclosed. Dicyandiamide is taken as a precursor and is calcined in two times to prepare a carbon nitride nanosheet; the carbon nitride nanosheet is dispersed in water, silver metavanadate quantum dots are subjected to in-situ growth to prepare a silver metavanadate quantum dot/carbon nitride nanosheet composite material; the silver metavanadate quantum dot/carbon nitride nanosheet composite material and graphene oxide carry out hydrothermal reaction, and are then frozen and dried to prepare silver metavanadate quantum dot/carbon nitride nanosheet/graphene hybrid aerogel which is the visible-light response hybrid aerogel. The problems of large reduction dosage, serious secondary pollution, complexity in operation and the like generated when waste gas is processed by a traditional flue gas denitration technology are overcome.

The present invention relates to a titania-based selective catalytic reduction (SCR) catalyst article which shows comparable or better performance to those which contain vanadium. In particular, the invention relates to the provision of a titania-based SCR catalyst article comprising ceria and niobia and to methods of making these catalysts.

Provided is a combustion system using a catalyst having better denitration efficiency at low temperatures, during a selective catalytic reduction reaction in which ammonia is used as a reducing agent.

This combustion system comprises: a combustion device that combusts fuel; an exhaust path through which flows exhaust gas generated from the combustion of fuel in the combustion device; a dust collection device that is arranged on the exhaust path and collects ash dust/dust in the exhaust gas; and a denitration device that is arranged on the exhaust path and removes nitrogen oxides from the exhaust gas by means of a denitration catalyst, wherein the denitration device is arranged downstream of the dust collection device on the exhaust path, and the denitration catalyst contains vanadium oxide including vanadium pentoxide and has a defect site in which an oxygen atom is deficient in a crystal structure of the vanadium pentoxide.

It is an object to provide a regenerated denitration catalyst whose denitration performance is restored compared with a denitration catalyst before use, utilizing a spent denitration catalyst, and a method for manufacturing the same. In a regenerated denitration catalyst according to the present disclosure, a spent denitration catalyst including a first titanium oxide as a main component, and a second titanium oxide are mixed. The spent denitration catalyst is already used in a denitration reaction in which nitrogen oxides in a gas are decomposed into nitrogen and water using a reducing agent. The second titanium oxide has a larger specific surface area per unit weight than the first titanium oxide. A content of the second titanium oxide based on a total weight of the first titanium oxide and the second titanium oxide is preferably 10% by weight or more and 90% by weight or less.

A catalyst for the conversion of NO.sub.X comprising iron chabazite and iron beta zeolite and a method of reducing the NOX concentration in a process gas stream comprising contacting the process gas stream with the catalyst. The catalyst is especially useful for high temperature deNO.sub.X conversion.

Indoor and outdoor air purifier including:—a fan for suctioning air and conveying it into—an air treatment duct suitable to disintegrate the toxic and pollutant components present in the air and then reintroducing the air, purified by now, into the external environment through one of the grids; within the duct, at least the following being installed: ∘ filters in any alveolar ceramic alloy treated with a titanium dioxide TiO.sub.2 nano-coating suitable to disintegrate the pollutant substances by a photocatalytic process activated thanks to ∘ LED lights, each of which installed in proximity to a corresponding filter, suitable to start the pollutant molecules disintegration photocatalytic process, reintroducing only the harmless substances into the atmosphere.