Process for treating a medium by the removal or destruction of one or more undesired substances present in said medium, comprising combining hydrogen peroxide and alkali hydroxide in an aqueous solution to form superoxide, and bringing the resultant superoxide-containing solution into contact with said medium. The process is useful for the destruction of halogenated organic pollutants and also for carbon dioxide removal from flue gases. The process can also be applied for soil remediation.

A method for managing and controlling nitrogen emission from a cyclic liquor flow system in a pulp mill (1), the pulp mill (1) comprising a recovery system (20) for recovering heat and chemicals from a pulping process (30), the recovery system (20) comprising a recovery boiler (8) and a nitrogen oxide scrubber (15), the nitrogen oxide scrubber (15) being arranged to remove nitrogen oxide from flue gas (16) from the recovery boiler (8), the method comprising the steps of: —exposing flue gas (16) from the recovery oiler (8) to an oxidizing agent, thereby oxidising nitrogen oxide in the flue gas (16) to higher nitrogen oxides; —contacting the flue gas (16) with an alkaline aqueous scrubber liquid (17) in the nitrogen oxide scrubber (15), thereby absorbing the nitrogen oxides in the scrubber liquid (17) and producing a nitrogen containing scrubber liquid (17); —introducing all or a part of the nitrogen containing scrubber liquid (17) into the cyclic liquor flow system. An arrangement for managing and controlling nitrogen emission from a cyclic liquor flow system in a pulp mill (1) is also disclosed.

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.

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.

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.

The invention relates to a process for preparing alkali carbonate/bicarbonate salts, comprising continuously feeding aqueous alkali hydroxide solution into a gas-liquid contactor; forcing incoming CO.sub.2-containing gas stream through a sparging device submerged in the gas-liquid contactor below the surface level of the aqueous alkali hydroxide solution, to generate bubbles and/or microbubbles; adding hydrogen peroxide in proximity to orifices of the sparging device, from which the bubbles and/or microbubbles evolve, wherein the supply of hydrogen peroxide is adjusted to decrease alkali carbonate formation and increase alkali bicarbonate formation; and continuously discharging an effluent from the gas-liquid contactor and recovering therefrom carbonate and bicarbonate alkali salts predominated by the bicarbonate component. A gas liquid-contactor and an apparatus are also provided by the invention.

An air sterilizing device, comprising: a housing (100), forming an air flow path thereon; an ozone generating unit (200), generating ozone particles to be supplied to the air flow path; a filter cartridge (300), receiving ozone generated by the ozone generating unit (200) to discharge bubbles comprising ozone and hydroxyl radicals; an ultrasonic generating unit (400), connected to the filter cartridge (300) to generate ultrasonic waves; an air supply fan (500), configured to supply air to the air flow path of the housing (100); and a power supply unit, configured to supply power for driving the ozone generating unit (200), the ultrasonic generating unit (400), and the air supply fan (500).

The present invention provides a process of cultivating microalgae and a joint method of same jointed with denitration. During the microalgae cultivation, EM bacteria is added into the microalgae suspension. In the nutrient stream for cultivating microalgae, at least one of the nitrogen source, phosphorus source and carbon source is provided in the form of a nutrient salt. During the cultivation, the pH of the microalgae suspension is adjusted with nitric acid and/or nitrous acid. The joint method includes (1) a step of cultivating microalgae; (2) a separation step of separating a microalgae suspension obtained from step (1) into a wet microalgae (microalgae biomass) and a residual cultivation solution; and (3) a NOx absorbing/immobilizing step of denitrating an industrial waste gas with the residual cultivation solution obtained from step (2). The nutrient stream absorbed with NOx obtained from step (3) is used to provide nitrogen source to the microalgae cultivation of step (1).

The invention discloses methods and apparatus(es) for the removal and control of pollutants such as gases and suspended particulates in the air of an enclosed space or an outdoor environment by passing the air through absorbent media. The absorbent media includes any liquid, solid or combination of liquid and solid media that is capable of absorbing a material in which it comes in contact. In one aspect of the invention, formaldehyde is removed by air sparging through a liquid such as water, optionally containing additional scavenging agents.

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.