A method for removing methane and non-methane volatile organic compound concentrations from a gas stream. The method includes exposing the target gas to a halogen gas and a light from a suitable light source having a wavelength sufficient to activate halogen gas to halogen radicals, wherein the halogen radicals react with the VOC in the target gas to provide the target gas with a removed concentration of VOC as well as a device including a reaction chamber for reacting the halogen radicals with the VOC in the target gas.

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

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.

Processes and systems for producing potassium sulfate as a byproduct of a desulfurization process. Sulfur dioxide is absorbed from a flue gas using an ammonia-containing solution to produce an ammonium sulfate solution that contains dissolved ammonium sulfate. At least a first portion of the ammonium sulfate solution is heated before dissolving potassium chloride therein to form a slurry that contains potassium sulfate crystals and an ammonium chloride solution. The slurry is then cooled to precipitate additional potassium sulfate crystals, after which the potassium sulfate crystals are removed to yield a residual ammonium chloride solution that contains dissolved ammonium chloride and residual dissolved potassium sulfate. Ammonia is then absorbed into the residual ammonium chloride solution to further precipitate potassium sulfate crystals, which are removed to yield a residual ammonium chloride solution that is substantially free of dissolved potassium sulfate.

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.

Disclosed herein are particulate sorbents, such as sorbents that can be used for mercury removal applications. The absorbent can comprise at least one ammonium phosphate and at least one activated carbon selected from unhalogenated activated carbon and halogenated activated carbon, wherein the halogenated activated carbon contains at least one halogen impregnant on its surface. Also disclosed are methods of making sorbents, and methods of mercury removal, e.g., from flue gas generated by coal combustion.

The present disclosure describes a hydrogen sulfide decomposition process for converting hydrogen sulfide into hydrogen gas and sulfur dioxide. Such a process can significantly increase the amount of available hydrogen gas. In fact, if each Claus unit in the U.S. creating elemental sulfur in traditional systems were replaced by this hydrogen sulfide decomposition process, 1.83 million metric tons of hydrogen gas could be produced. This represents about 20% of the annual hydrogen produced in the U.S. for any purpose, recovered and available for reuse. Additionally, if desired, the sulfur dioxide can be further processed to form sulfuric acid.

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

Some aspects of the present disclosure relate to a method comprising obtaining a sorbent polymer composite material, contacting the sorbent polymer composite material with mercury vapor to form a used sorbent polymer composite material; wherein the used sorbent polymer composite material comprises oxidized mercury and wherein the used sorbent polymer composite material emits oxidized mercury vapor; and contacting the used sorbent polymer composite material with a halogen source, so as to result in a treated sorbent polymer composite material. In some embodiments, the treated sorbent polymer composite material emits less than 0.01 g oxidized mercury vapor per minute per gram of the treated sorbent polymer composite, compared to a used sorbent polymer composite, when measured at 65 C. in air having a relative humidity of 95%.

The present disclosure relates to systems and methods of making ammonia using stable ammonia absorbents. The system and method for producing ammonia, comprises a reactor comprising a catalyst that converts at least a portion of nitrogen feed gas and at least a portion of hydrogen feed gas to ammonia (NH3) forming a reaction mixture comprising the ammonia, unreacted nitrogen, and unreacted hydrogen. An absorber configured to selectively absorb ammonia from the reaction mixture at a temperature of about 180 deg. C. to 330 deg. C. and a pressure of about 1-20 bar, the absorber comprising a solid absorbent. Preferably the solid absorbent is at least one metal halide and a solid support. The unabsorbed ammonium, the unreacted nitrogen, and unreacted hydrogen gas are recycled to the reactor.