An alkaline aqueous ferric iron salt solution is disclosed. Generally, the alkaline aqueous ferric iron salt solution comprises ferric ions (Fe.sup.3+), potassium ions (K.sup.+), carbonate ions (CO.sub.3.sup.2−), bicarbonate ions (HCO.sub.3.sup.−), hydroxide ions (OH.sup.−), optionally nitrate ions (NO.sub.3.sup.−). Further, a molar ratio of the potassium ions to the ferric ions is generally at least 5.0. The ferric iron is complexed with carbonate, bicarbonate or both to form a water-soluble complex that is anionic in nature and highly soluble in the alkaline aqueous ferric iron salt solution at pH above 8.5, and a pH of the alkaline aqueous ferric iron salt solution is at least 8.5.

The invention relates to a process for separating off and/or recovering nitrogen compounds, in particular for separating off ammonia and/or recovering or producing nitrogen fertilizer, from a liquid or sludge substrate, in which a liquid or sludge substrate is introduced into a degassing vessel to which subatmospheric pressure is applied and ammonia gas formed is introduced by means of a vacuum pump into at least one scrubber which is located downstream of the degassing vessel and to which subatmospheric pressure is applied and into which acid is introduced, wherein the acid or an ammonium salt-containing liquid obtained in the at least one scrubber is taken off from the at least one scrubber, cooled and subsequently sprayed back into the at least one scrubber. The invention further relates to a plant for carrying out such a process.

A method for capturing CO.sub.2 comprising dissolving at least one pure amino acid (AA) in water without the use of a catalyst for establishing protonation of an amino group of the amino acid, adding at least one base solution to the amino acid and water solution to deprotonate the protonated amino group of the amino acid and forming an amino acid-XOH—H.sub.2O wherein X is sodium or potassium, and subjecting CO.sub.2 to the amino acid-XOH—H.sub.2O to form new nanomaterials is provided. A regenerable nanofiber is disclosed comprising a NaHCO.sub.3 nanofiber, a KHCO.sub.3 nanofiber, or an amino acid nanofiber made from subjecting a CO.sub.2 gas to an amino acid aqueous solvent. Preferably, the amino acid aqueous solvent is one or more of a Gly-NaOH—H.sub.2O, an Ala-NaOH—H.sub.2O, a Phe-NaOH—H.sub.2O, a Gly-KOH—H.sub.2O, an Ala-KOH—H.sub.2O, and a Phe-KOH—H.sub.2O.

The present invention provides processes for filtering undesired chemicals in streams of contaminated air for supply to confined areas. The processes provide (1) contacting air with a filter comprising by volume from about 5% to about 95% impregnated zirconium hydroxide, from about 5% to about 95% activated impregnated carbon, and optionally, up to about 50% ammonia removal material; and (2) supplying the contacted air to a confined area.

A flue gas desulfurization unit is converted from operating with lime or magnesium enhanced lime under inhibited oxidation into a unit that operates using limestone under inhibited oxidation conditions. A ball mill grinding unit may be installed to crush the limestone thereby producing a suspended slurry of fine limestone particles which is pumped to the reaction vessel. When installed, the ball mill may be installed in the process immediately downstream of the existing slaking equipment. The suspended solution may be maintained at a pH in the range of 3.0 to 6.5, optimally at approximately 5.0 to increase the dissolution rate of the limestone reagent produced by the ball mill. The post-conversion process may also require the addition of organic acids and oxidation inhibitors to achieve better SO.sub.2 removal from the flue gas.

Disclosed herein is a system for purifying air; for the capture of solid residues (soot), and the transformation of CO.sub.x and NO.sub.x (and even methane) present in contaminated air generated by industrial combustion.

The purifying air system comprises an air entrance (c); a first module (A), made up of mechanical filters; a second module (B), downwards from the first module (A), and it corresponds to a series of small reactors with molecular converters (nucleophile chemical agents) to capture and transform carbon oxides (CO.sub.x) and nitrogen oxides (NO.sub.x); and an exit for decontaminated air (D).

The invention relates to a method for cleaning the process gas in soldering installations and solder suction systems, in particular for reducing the abietic acid in the process gas, wherein the process gas to be cleaned is conducted through a cleaning system which contains one or more of the following compounds (cleaning compounds): a) carboxylic acids with reducing properties, namely oxalic acid, formic acid, citric acid and/or ascorbic acid: b) metal compounds of higher oxidation states, namely manganates, permanganates, chromates and/or dichromates; c) alcohols which can be convened into the carboxylic acids mentioned in a) by means of oxidation; d) basic lime compounds.

Disclosed are methods and systems for removing submicron particles from a gas stream, in particular from urea prilling off-gas, wherein a Venturi ejector is used. A method comprises contacting a gas stream containing submicron particles in a Venturi ejector with an injected high velocity scrubbing liquid to provide a pumping action, wherein the scrubbing liquid has an initial velocity of at least 25 m/s and wherein the ratio of scrubbing liquid and gas flow is between 0.0005 and 0.0015 (m.sup.3/h)/(m.sup.3/h).

A water generation system for generating liquid water from a process gas containing water vapor is disclosed. In various embodiments, the water generation systems comprise a solar thermal unit, a condenser and a controller configured to operate the water generation system between a loading operational mode and a release operational mode for the production of liquid water. A method of generating water from a process gas is disclosed herein. In various embodiments, the method comprises flowing a process gas into a solar thermal unit, transitioning from the loading operational mode to a release operational mode; flowing a regeneration fluid into the solar thermal unit and the condenser during the release operational mode; and, condensing water vapor from the regeneration fluid to produce liquid water.

In accordance with some embodiments herein, a filtering product is provided. The filtering product includes titanium dioxide (TiO.sub.2), cetrimonium bromide (CTAB) and ascorbic acid (C.sub.6H.sub.8O.sub.6). The filtering product may be used for filtering smoke of a water pipe. Alternatively and/or additionally, the filtering product may be used for filtering gas.