The use of a composition including at least one acido-basic neutralising agent for decontaminating an atmosphere contaminated by a corrosive gas, the acido-basic neutralising agent having at least 2 pKa's and being characterised by: pKa 1≤pKa 2, pKa 1>2, pKa 2<12, 4<½ (pKa 1+pKa 2)<10 pKa 1, representing the smallest of the basic pKa's and pKa 2 representing the largest of the acidic pKa's. Also, a method for decontaminating an atmosphere contaminated by a corrosive gas comprising the spraying of the neutralising agent, and to a decontamination device.

A method for reducing pollution in exhaust gases and a system for treating exhaust gas are provided. The method includes the step of treating an exhaust gas stream with a treating fluid. In one application, the treating fluid is injected by spraying droplets into the exhaust gas stream. A system for treating exhaust gas includes a reagent, and a nozzle to spray the reagent into the exhaust gas stream.

A treatment composition for remediating for remediating H.sub.2S and other contaminant(s) in contaminated gasses comprising: an aqueous hydroxide solution containing at least one hydroxide compound at a collective concentration of 35-55 weight percent of the aqueous hydroxide solution; at least one organic acid selected from the group consisting of fulvic acid and humic acid; and a chelating agent, wherein the aqueous hydroxide solution constitutes at least 80 wt % of the treatment composition, the at least one organic acid constitutes 0.1-3 wt % of the treatment composition, the chelating agent constitutes 0.1-6 wt % of the treatment composition, and a pH of the treatment composition is at least 12.0.

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.

A carbon dioxide fixation method includes a step of preparing a calcium-containing substance containing calcium, a step of preparing a calcium extraction substance for extracting calcium ions from the calcium-containing substance by a reaction with the calcium-containing substance to produce a calcium-containing intermediate, a step of producing a gel including the calcium-containing intermediate, by mixing the calcium-containing substance and the calcium extraction substance, a step of supplying a basic substance and carbon dioxide to the gel including the calcium-containing intermediate to precipitate calcium carbonate which is slightly soluble, and a step of removing the precipitated calcium carbonate.

A treatment process for remediating H.sub.2S and other contaminants in liquids includes: partially filling a closed vessel with a contaminated liquid containing ≥5 ppm H.sub.2S with a head space above the liquid within the vessel where gasses released from the liquid from the liquid collect; separately providing a treatment composition in the head space so that the gasses from the liquid may contact the treatment composition; and permitting the contact between the vapors from the liquid and the treatment composition to continue until a collective concentration of H.sub.2S in the liquid and in the head space is <5 ppm. The treatment composition includes an aqueous solution containing at least one hydroxide compound, a collective concentration of the at least one hydroxide compound in the aqueous solution is in a range of 35-55 weight %, and the aqueous solution constitutes at least 80 weight % of the treatment composition.

The invention disclosed herein relates to an odor control system including features to allow a media scrubber to function to treat a humid, or saturated, or superheated exhaust stream. In some embodiments, the system disclosed herein can capture a humid, or saturated, or superheated exhaust stream, such as from a kettle vent, and dilute the exhaust with fresh air to lower the temperature of the combined air flow below its dew point. Water is drained from the system as it condenses in the system. The combined air flow can be further diluted and/or treated according to embodiments disclosed herein such that the exhaust stream, after having excess water removed, will have a relative humidity (RH) value enabling it to be run through a media scrubber.

There are provided methods for treating a gas having an undesirable odor. The methods comprise contacting the gas with an acidic aqueous oxidizing composition having a pH of about 2.0 to about 3.0 and comprising at least one cation of a metal; a sequestering agent; and H.sub.2O.sub.2 and submitting the gas and the composition to UV radiation when the gas and the composition are contacting each other, wherein the treatment permits to reduce by at least 60% intensity of the undesirable odor.

Methods and systems for capturing and storing carbon dioxide are disclosed. In some embodiments, the methods include the following: mixing materials including magnesium or calcium with one or more acids and chelating agents to form a magnesium or calcium-rich solvent; using the organic acids derived from biogenic wastes as acids or chelating agents; generating carbonate ions by reacting a gas including carbon dioxide with a carbonic anhydrase biocatalyst; reacting the solvent with the carbonate ions to form magnesium or calcium carbonates; recycling a solution containing the biocatalyst after forming magnesium or calcium carbonates for re-use in the generating step; using the magnesium and calcium carbonates as carbon neutral filler materials and using the silica product as green filler materials or inexpensive absorbents.

A recombinant microorganism including a genetic modification that increases activity of nitric oxide reductase in the recombinant microorganism, a composition for reducing a concentration of nitric oxide in a sample, the composition including the recombinant microorganism, and a method of reducing a concentration of nitric oxide in a sample, are disclosed.