The present invention relates to a systems and methods for improved removal of one or more species in a process stream, such as combustion product stream formed in a power production process. The systems and methods particularly can include contacting the process stream with an advanced oxidant and with water.

A gas processing apparatus includes a duct, a partition plate and a liquid supply. The duct has therein a flow path through which a gas passes. The partition plate is configured to divide the flow path into multiple spaces, and is formed of a porous material, through which the gas passes, configured to retain a liquid. The liquid supply is configured to supply a dissolving liquid configured to dissolve a target component contained in the gas to the partition plate. The gas passing through the flow path is brought into contact with the dissolving liquid retained in the partition plate.

A method for improving indoor air quality in a room, comprising drawing air from the room and guiding the air into a gas/liquid contactor charged with aqueous alkali hydroxide/H.sub.2O.sub.2 solution, passing the air through a perforated membrane installed in the gas/liquid contactor below the surface level of the aqueous alkali hydroxide/H.sub.2O.sub.2 solution, such that bubbles produced travel through said solution, and getting treated air with improved quality from said gas/liquid contactor, said treated air is characterized by having: reduced carbon dioxide levels; and/or reduced VOC levels; and/or reduced microbiological load. An air purifier to carry out the method is also provided.

A process for recovering nitric acid or salts thereof, comprising: contacting, in the presence of water, an water-immiscible ionic liquid of the formula [A.sup.+][X.sup.−], wherein [A.sup.+] represents a phosphonium or ammonium cation and [X.sup.−] represents a counter anion which is NO.sub.3.sup.−, an halide anion displaceable by NO.sub.3.sup.−, or both, with a fluid which contains HNO.sub.3 and at least one more mineral acid, or precursors of said acids, and partition, under mixing, said acids between aqueous and organic phases and form nitrate-loaded ionic liquid of the formula [A.sup.+][NO.sub.3.sup.−].sub.z>0.25 where Z indicates a molar amount of nitrate held in the ionic liquid beyond the positions occupied by the nitrate counter ions; separating the so-formed mixture into an organic phase comprising a nitrate-loaded ionic liquid of the formula [A.sup.+][NO.sub.3.sup.−].sub.z>0.25 and an aqueous phase consisting of a nitrate-depleted aqueous solution that contains the other mineral acid(s); stripping the nitric acid from said nitrate-loaded ionic liquid to create an aqueous nitrate solution and regenerate ionic liquid of the formula [A.sup.+][NO.sub.3.sup.−].sub.z≥0 with reduced nitrate loading, or unloaded [A.sup.+][NO.sub.3.sup.−].sub.z=0 ionic liquid.

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.

Some embodiments of the present disclosure relate to a method of regenerating at least one filter medium comprising: providing at least one filter medium, wherein the at least one filter medium comprises: at least one catalyst material; and ammonium bisulfate (ABS) deposits, ammonium sulfate (AS) deposits, or any combination thereof; flowing a flue gas stream transverse to a cross-section of a filter medium, such that the flue gas stream passes through the cross section of the at least one filter medium, wherein the flue gas stream comprises: NOx compounds comprising: Nitric Oxide (NO), and Nitrogen Dioxide (NO.sub.2); and increasing an NOx removal efficiency of the at least one filter medium after removal of deposits.

A system, a use of such a system and a multi system for cleaning exhaust gas from a combustion engine. The system comprises a first exhaust gas scrubber to communicate with a scrubber water circulation tank. A first outlet of the first exhaust gas scrubber is connectable to a first inlet of the scrubber water circulation tank, and a first inlet of the first exhaust gas scrubber is connectable to a first outlet of the scrubber water circulation tank, to enable circulation of scrubber water between the scrubber water circulation tank and the first exhaust gas scrubber. An air supply device feeds air into the first exhaust gas scrubber to aerate the scrubber water during its passage through the first exhaust gas scrubber. Accordingly, a second inlet of the first exhaust gas scrubber is arranged to be connected to an outlet of the air supply device.

A method of reducing hydrogen sulfide content in a medium is disclosed. The method may include the steps of contacting a medium containing hydrogen sulfide with an effective amount of hydrogen peroxide, contacting the medium with an oxidizing agent, converting the hydrogen sulfide to sulfate, and reducing the hydrogen sulfide content in the medium. The medium may be a gas or a liquid.

A method for preparing Cl—SO.sub.2NHSO.sub.2Cl including a step of chlorinating sulphamic acid with at least one chlorinating agent and at least one sulphur-containing agent, the method resulting in a flow F1, preferably liquid, including Cl—SO.sub.2NHSO.sub.2Cl and a gas stream F2 including HCl and SO.sub.2, the method including a step a) of treating the gas stream F2. Also, a method for preparing LiFSl including the abovementioned method for preparing Cl—SO.sub.2NHSO.sub.2Cl.

An oxidation-reduction desulfurization system includes a reactor vessel with sour gas inlet at the bottom and a gas outlet at the top. A primary stage phase separator includes a vertically-oriented pipe with an inlet located inside the reactor vessel. The ratio of the reactor vessel diameter to the pipe inlet diameter is in a range of 2:1 to 5:1. Surface foam and non-gaseous multi-phase mixture including emulsion flow into a partially gas-filled upper section of the vertically-oriented pipe and freefall to a lower level, thereby facilitating mechanical breaking of the foam and the emulsion. A secondary stage phase separator connected to the gas outlet separates non-gaseous surge from sweet gas. Valves and a controller automatically maintain target levels of the non-gaseous multi-phase mixture and non-gaseous surge.