This invention relates to methods and compositions for removing contaminants from fluids, for example, the removal of mercury contaminants by oxidation. The compositions and methods provided herein are robust and accomplish efficient removal of contaminants from fluid streams without the need for relatively expensive activated carbon. In addition, the methods and compositions of the present invention do not pose risks to the safety of workers through the injection of highly toxic, highly corrosive elemental bromine to directly oxidize the mercury. The compositions and methods of the present invention are versatile and apply to a wide range of contaminants including, but not limited to, mercury, lead, cadmium, thallium, and hydrogen sulfides. Further, the compositions and methods contained herein are capable of efficient contaminant removal over a wide range of temperatures and pressures.

A contaminant reducing device is provided. The contaminant reducing device comprises: an exhaust gas tube for supplying exhaust gas from a combustion engine; a cleaning water supply tube for supplying cleaning water; a scrubber for spraying cleaning water, which is supplied through the cleaning water supply tube, to exhaust gas supplied through the exhaust gas tube; an oxidation unit connected to the exhaust gas tube so as to oxidize the exhaust gas by discharging electricity, emitting ultraviolent rays, or spraying an oxidizer; and a cleaning water discharge tube for discharging cleaning water from inside the scrubber.

Methods related generally to the removal of atmospheric pollutants from the gas phase, are provided, as well as related apparatus, processes and uses thereof. A single-stage air scrubbing apparatus is provided that includes at least one reaction vessel, at least one introduction duct, and a turbulence component, wherein a residence time is sufficient to allow the conversion of at least one atmospheric pollution compound to at least one other compound, molecule or atom. In some embodiments, the at least one atmospheric pollution compound comprises nitrogen oxide, sulfur oxide or a combination thereof. Additionally, methods of removing atmospheric pollution compounds from a waste gas stream are disclosed that include introducing a waste gas stream and at least one additional gas stream, mist stream, liquid stream or combination thereof into a single-stage air scrubbing apparatus at a flow rate sufficient to allow for conversion of the at least one atmospheric pollution compound.

The present disclosure is directed to the use of elemental or speciated iodine and bromine to control total mercury emissions.

A method for controlling mercury emissions within a FGD system, the method includes preparing a treatment composition for application on FGD system components, the treatment composition comprising a biocide, applying the treatment composition to an FGD system, wherein the FGD system includes an FGD scrubber, monitoring the bacterial load present within the FGD system, and optimizing the operating conditions of an aqueous system to determine when additional treatment is required.

A device controls levels of carbon dioxide and water in a controlled environment. The device comprises a first electrode chamber, which receives an input fluid comprising first concentrations of carbon dioxide and water and is configured to deliver a first output fluid having concentrations of carbon dioxide and water lower than the first concentrations to a first environment, and a second electrode chamber having an outlet configured to deliver a second output fluid having third concentrations of carbon dioxide and water to a second environment. A reduction catalyst layer in the first electrode chamber reduces carbon dioxide and water in the input fluid to form ionic carrier species, an ion-transporting membrane is positioned between the first and second electrode chambers and comprises carrier species, and an oxidation catalyst layer in the second electrode chamber oxidizes the ionic carrier species to form carbon dioxide and water.

The present disclosure relates to a flue gas treatment system (e.g. a multi-pollutant flue gas treatment system) for removal of greenhouse gases such as SO.sub.2, NO, NO.sub.2, H.sub.2S, HCl, water and CO.sub.2 as well as heavy metals (e.g. mercury, arsenic, bismuth, cadmium, lead and/or selenium) from the flue gases of fossil-fueled utility and industrial plants by reacting the raw flue gas, firstly, with chlorine in a gas-phase oxidation reaction and recovering the resulting products as marketable products, and then, secondly, treating the cleaned gas, which includes CO.sub.2, with a Sabatier reaction to produce a hydrocarbon fuel (e.g. methane). The system also includes an electrolytic unit for electrolyzing HCl to produce hydrogen gas for the Sabatier reaction as well as chlorine gas, which may then be recycled into the reactor.

The present invention provides a method and apparatus for removing mercury from gases such as those discharged from roasters and other heat producing systems. In embodiments the method comprises reacting the mercury with dissolved molecular chlorine, and may also comprise reacting the mercury with mercuric chloride to yield mercurous chloride. The mercurous chloride may be removed by precipitation. There are also disclosed apparatuses for implementing the method.

A pollutant reduction device and method are provided. The pollutant reduction device comprises: an exhaust gas pipe for discharging exhaust gas of a combustion engine; a cleaning water supply pipe for supplying cleaning water; a scrubber for spraying the cleaning water, which is supplied through the cleaning water supply pipe, at the exhaust gas flowing in through the exhaust gas pipe; and a cleaning water discharge pipe for discharging the cleaning water inside the scrubber and supplying the same to a ballast water tank.

One aspect of the invention relates to a method comprising a single-stage conversion of an atmospheric pollutant, such as NO, NO.sub.2 and/or SO.sub.x in a first stream to one or more mineral acids and/or salts thereof by reacting with nonionic gas phase chlorine dioxide (ClO.sub.2.sup.0), wherein the reaction is carried out in the gas phase. Another aspect of the invention relates to a method comprising first adjusting the atmospheric pollutant concentrations in a first stream to a molar ratio of about 1:1, and then reacting with an aqueous metal hydroxide solution (MOH). Another aspect of the invention relates to an apparatus that can be used to carry out the methods disclosed herein. The methods disclosed herein are unexpectedly efficient and cost effective, and can be applied to a stream comprising high concentration and large volume of atmospheric pollutants.