The present disclosure relates to systems and methods for separation of sulfurous material(s) from a multi-component feed stream. The systems and methods can comprise contacting the multi-component feed stream with a solvent in a contacting column so that at least a portion of the sulfurous material(s) is transferred from the multi-component feed stream to the solvent. A stream of a substantially purified gas can thus be provided along with a liquid stream comprising at least a majority of the sulfurous material. In particular, the solvent can comprise liquid carbon dioxide, which can be particularly beneficial for removing sulfurous materials from multi-component feed streams.

According to one embodiment, a gas processing equipment includes an oxygen remover 2 that removes oxygen contained in exhaust gas G, and a gas processing device 3 that processes pretreated exhaust gas G (P), from which the oxygen has been removed by the oxygen remover 2, with a carbon dioxide absorbent solvent S as a treatment agent.

A treatment method for reducing carbon dioxide emission of combustion exhaust gas includes: a caustic soda synthesis step; a treatment step of reducing carbon dioxide emission of combustion exhaust gas; and a recycling step. In the caustic soda synthesis step, a natural sodium carbonate aqueous solution (Na.sub.2CO.sub.3) prepared by dissolving natural sodium carbonate ore powder composed of Na.sub.2CO.sub.3 and NaHCO.sub.3 in a caustic soda aqueous solution is used to generate a caustic soda aqueous solution and calcium carbonate precipitate by a causticization reaction with slaked lime, and solid-liquid separation is performed to obtain a synthetic caustic soda aqueous solution. In the treatment step, the synthetic caustic soda aqueous solution and purified combustion exhaust gas are brought into gas-liquid countercurrent contact so that carbon dioxide in the exhaust gas is absorbed by the synthetic caustic soda aqueous solution and immobilized as sodium carbonate.

A system comprises an electrochemical liquid desiccant regeneration system, a first air contactor, and a second air contactor. The regeneration system comprises a first output stream having a first concentration of liquid desiccant and a second output stream having a second, lower concentration. The first air contactor disposes a first input air stream having a first water concentration in fluid communication with the first output stream to form a first output air stream having a second, lower water concentration and a diluted output stream, which is circulated back into the regeneration system. The second air contactor disposes a second input air stream having a third water concentration in fluid communication with the liquid desiccant output stream to form a second output air stream having a fourth water concentration higher than the third water concentration and a concentrated output stream, which is circulated back into the regeneration system.

A method of removing water from a mixture of hydrogen iodide (HI) and water includes providing a mixture comprising hydrogen iodide and water and contacting the mixture with an adsorbent to selectively adsorb water from the mixture, contacting the mixture with a weak acid to absorb water from the mixture and/or separating the water from hydrogen iodide (HI) by azeotropic distillation to produce anhydrous hydrogen iodide (HI).

Methods of recovering iodine (I.sub.2) from a stream including iodine (I.sub.2) vapor and at least one of: an inert gas and water vapor can include contacting the stream with an alkaline solution to form an iodide salt, contacting the stream with an adsorbent to selectively adsorb water from the stream, contacting the stream with a concentrated acid to absorb the water vapor from the stream, desublimating or condensing the iodine (I.sub.2) vapor to form solid or liquid iodine (I.sub.2), or contacting the stream with a material to condense or de-sublimate the iodine (I.sub.2) vapor from the stream as the material at least one of: absorbs latent heat through a phase change of the material and absorbs sensible heat.

A method of removing water from a mixture of iodine (I.sub.2) and water includes providing a mixture comprising iodine and water and: contacting the mixture with an adsorbent to selectively adsorb water from the mixture, contacting the mixture with a concentrated acid to absorb water from the mixture, separating the water from mixture by distillation, contacting the mixture with a gas that is inert to iodine (I.sub.2), contacting the mixture with hydrogen iodide (HI), or combinations thereof.

The removal of acid gases (e.g., non-carbon dioxide acid gases) using sorbents that include salts in molten form, and related systems and methods, are generally described.

A system comprises a liquid desiccant regeneration system, a first air contactor stage, and a second air contactor stage. The regeneration system has a first stage with a first concentration output and first diluted output, and a second stage with a second concentration output, different from the first concentration output, and a second diluted output. The first air contactor stage is coupled to the first concentrated output to form a first output air stream having a reduced water content and a first diluted air contactor output. The second air contactor stage is coupled to the second concentrated output to form a second output air stream having a reduced water content and a second diluted air contactor output. Both diluted air contactor outputs are recirculated into the regeneration system, and the output air streams are combined.

Methods and systems for converting ammonium waste streams into certifiably Organic ammonium salts having a variety of uses in greenhouse gas-reducing activities are herein described. The resulting ammonium salt compositions can be used to enhance crop yield.