A gas exchange device for filtering a gas is provided. The gas exchange device includes a gas-intake channel having a gas-intake-channel inlet and a gas-intake-channel outlet, a gas-exhaust channel disposed aside the gas-intake channel and including a gas-exhaust-channel inlet and a gas-exhaust-channel outlet, a purification unit disposed in the gas-intake channel for filtering the gas passing through the gas-intake channel, a gas-intake guider and a gas-exhaust guider for guiding the gas, a driving controller disposed in the gas-intake channel near the gas-intake guider for controlling enablement and disablement of the purification unit, the gas-intake guider and the gas-exhaust guider, and a gas detection main body for detecting the gas and generating detection data.

A desulfurization and denitration method includes adding an aqueous solution of a chlorate, an aqueous solution of a peroxide, and an aqueous solution of sulfuric acid to a chlorine dioxide generator to obtain gaseous chlorine dioxide, and mixing the gaseous chlorine dioxide with air to obtain a mixed gas. The gaseous chlorine dioxide is 4-10 vol % of the mixed gas. The method includes letting the mixed gas come into contact with a flue gas to obtain an oxidized flue gas. A molar ratio of the gaseous chlorine dioxide in the mixed gas to nitric oxide in the flue gas is 1-1.8. The final step includes passing the oxidized flue gas to the desulfurization and denitration tower and mixing the oxidized flue gas with a spray of an alkaline absorbent dry powder, and spraying water into the desulfurization and denitration tower to obtain a desulfurized and denitrated flue gas.

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.

A method for the reduction and prevention of mercury emissions into the environment from combusted fossil fuels or other off-gases with the use of peracetic acid is disclosed. The peracetic acid is used for the capture of mercury from the resulting flue gases using a flue gas desulfurization system or scrubber. The method uses peracetic acid in conjunction with a scrubber to capture mercury and lower its emission and/or re-emission with stack gases. The method allows the use of coal as a cleaner and environmentally friendlier fuel source as well as capturing mercury from other processing systems.

The present disclosure provides systems and methods useful in capture of one more moieties (e.g., carbon dioxide) from a gas stream (i.e., direct air capture). In various embodiments, the systems and methods can utilize at least a scrubbing unit, a regeneration unit, and an electrolysis unit whereby an alkali solution can be used to strip the moiety (e.g., carbon dioxide) from the gas stream, the removed moiety can be regenerated and optionally purified for capture or other use, and a formed salt can be subjected to electrolysis to recycle the alkali solution back to the scrubber for re-use with simultaneous production of one or more further chemicals.

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

Various embodiments disclosed relate to sorbents for the oxidation and removal of mercury. The present invention includes removing mercury from a mercury-containing gas using a halide-promoted and optionally ammonium-protected sorbent that can include carbon sorbent, non-carbon sorbent, or a combination thereof.

The disclosure relates generally to reducing mercury emissions from a coal power plant. Specifically, a method for treating a gas stream containing mercury is provided that includes injecting a mercury oxidant or absorbent and a carrying agent into a gas stream that was produced by heating or burning a carbonaceous fuel comprising mercury. The carrying agent vaporizes after being injected into the gas stream. The mercury oxidant or absorbent and a carrying agent may be injected before passing the gas stream into a gas 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.

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.