A method for producing and using an alkaline aqueous ferric iron carbonate solution is disclosed. The method broadly comprises reacting at least one ferric iron salt reagent with at least one alkali metal carbonate salt reagent and forming an alkaline aqueous ferric iron carbonate solution comprising an aqueous-soluble, ferric iron carbonate complex. The reacting generally includes reacting a solid with an aqueous solution. The reacting may include reacting a solid comprising one or both of the ferric iron salt reagent and alkali metal carbonate salt reagent with an aqueous solution. A method for removing reduced sulfur compounds from a reduced sulfur-containing fluid is also disclosed.

The structured catalyst for oxidation for exhaust gas purification includes a support having a porous structure constituted by a zeolite-type compound, and at least one type of oxidation catalyst that is present in the support and selected from the group consisting of metal and metal oxide, the support having channels that communicate with each other, and the oxidation catalyst being present in at least the channels of the support.

A composite, zone-coated, dual-use ammonia (AMOX) and nitric oxide oxidation catalyst (12) comprises: a substrate (5) having a total length L and a longitudinal axis and having a substrate surface extending axially between a first substrate end (I) and a second substrate end (O); two or more catalyst washcoat zones (1; 2) comprised of a first catalyst washcoat layer (9) comprising a refractory metal oxide support material and one or more platinum group metal components supported thereon and a second catalyst washcoat layer (11) different from the first catalyst washcoat layer (9) and comprising a refractory metal oxide support material and one or more platinum group metal components supported thereon, which two or more catalyst washcoat zones (1; 2) being arranged axially in series on and along the substrate surface, wherein a first catalyst washcoat zone (1) having a length L.sub.1, wherein L.sub.1<L, is defined at one end by the first substrate end (I) and at a second end (13) by a first end (15) of a second catalyst washcoat zone (2) having a length L.sub.2, wherein L.sub.2<L, wherein the first catalyst washcoat zone (1) comprises a first refractory metal oxide support material and one or more platinum group metal components supported thereon; and the second catalyst washcoat zone comprises a second refractory metal oxide support material and one or more platinum group metal components supported thereon; and a washcoat overlayer (G) extending axially from the first substrate end for up to 200% of the axial length of the underlying first catalyst washcoat layer, which washcoat overlayer comprising a particulate metal oxide loading of >48.8 g/l (>0.8 g/in.sup.3), wherein the particulate metal oxide is an aluminosilicate zeolite including at least one of copper, iron and manganese, wherein a total platinum group metal loading in the first catalyst washcoat zone (1) defined in grams of platinum group metal per litre of substrate volume (g/l) is different from the total platinum group metal loading in the second catalyst washcoat zone (2).

The invention relates to a catalyst comprising a mixture of AFX-structure and BEA-structure zeolites and at least one additional transition metal, to the process for preparing same and to the use thereof for the selective catalytic reduction of NOx in the presence of a reducing agent such as NH.sub.3 or H.sub.2.

Disclosed is a method of controlling an air supply system for a fuel cell. The air supply system includes a fuel cell stack, an air channel to supply air to an inlet of the fuel cell stack, a gas adsorption unit disposed on the air channel and configured to adsorb oxygen contained in air introduced into the air channel. In particular, the method includes: determining whether a power generation operation of the fuel cell stack is resumed; when the power generation operation of the fuel cell stack is resumed, controlling a voltage source to apply a voltage to the gas adsorption unit; and supplying air to the fuel cell stack through the air channel in a state in which the voltage is applied to the gas adsorption unit.

A particulate filter having a porous ceramic honeycomb structure with a first end, a second end, and a plurality of walls having wall surfaces defining a plurality of inner channels. Filtration material deposits are disposed on one or more of the wall surfaces of the honeycomb body. The highly porous deposits provide durable high clean filtration efficiency with small impact on pressure drop through the filter.

A catalyst composition for treating an exhaust gas, the catalyst composition comprising a molecular sieve, the molecular sieve comprising exchanged copper and exchanged manganese.

Proposed is a pretreatment desulfurization method for marine fuel oil. The method includes a step of preparing a pretreatment desulfurization agent including (a) at least one oxide selected from the group consisting of SiO2, Al2O3, Fe2O3, TiO2, MgO, MnO, CaO, Na2O, K2O, and P2O3, (b) at least one metal selected from the group consisting of Li, Cr, Co, Ni, Cu, Zn, Ga, Sr, Cd, and Pb, and (c) at least one liquid composition selected from the group consisting of sodium tetraborate (Na2B4O7.10H2O), sodium hydroxide (NaOH), sodium silicate (Na2SiO3). and hydrogen peroxide (H2O2). The method also includes a step of feeding the pretreatment desulfurization agent to a fuel supply line through which marine fuel oil is supplied to a marine engine at a certain ratio so that a fluid mixture containing the marine fuel oil and the pretreatment desulfurization agent is supplied to the marine engine, thereby adsorbing and removing sulfur oxides during combustion of the fluid mixture.

A process is presented to treat a process gas stream containing hydrogen sulfide using a reverse jet absorber with a liquid treatment solution containing a chelated metal catalyst. A treat gas substantially free of the hydrogen sulfide is separated from a spent liquid treatment solution containing elemental sulfur which can then be regenerated in an oxidation vessel where it is contacted with an oxygen containing gas to convert the spent liquid treatment solution to a regenerated liquid treatment solution that can be recycled for introduction into the reverse jet absorber.

Zeolite catalysts and systems and methods for preparing and using zeolite catalysts having the CHA crystal structure are disclosed. The catalysts can be used to remove nitrogen oxides from a gaseous medium across a broad temperature range and exhibit hydrothermal stable at high reaction temperatures. The zeolite catalysts include a zeolite carrier having a silica to alumina ratio from about 15:1 to about 256:1 and a copper to alumina ratio from about 0.25:1 to about 1:1.