Abstract: Method of concentrating aqueous solutions of non-volatile, ionic solutes by extracting water from the solution by means of a polar organic liquid (or a solution of a polar organic liquid and a non-polar organic liquid) at an elevated temperature and cooling the organic liquid to separate a water phase, the extractant and the temperatures being chosen such that water has a relatively high solubility in the extractant at the higher temperature and a relatively low solubility at the lower temperature; the extractant being also chosen to meet certain other criteria such as inertness toward the solution and equipment. Advantage is taken of the diminished activity coefficient of water in polar organic liquids at elevated temperatures and in the case of certain solutions, advantage is also taken of the increased activity coefficient of water in aqueous ionic solution at elevated temperatures.

Abstract: Process of carrying out oxidation-reduction reactions such as oxidation of hydrogen sulfide to sulfur, in which a polyvalent metal chelate with a certain class of polycarboxylic acid is employed, the metal being reduced from a higher valence state to a lower valence state during reduction and back to the higher valence state by oxidation. The class of polycarboxylic acids are those which have a substituent which enhances acidity yet is stable toward oxidation.

Abstract: Presented is an apparatus and method for producing small quantities of chlorine and sodium hydroxide or sodium hypochlorite, useful in many applications where the major investment of a full-blown chemical plant capable of producing tons of product per day is not economically feasible. The apparatus of the invention includes the use of an electrolytic cell embodying an anode chamber charged with an acidic, concentrated sodium chloride solution and a cathode chamber charged with a basic aqueous solution and through which an electric current may be passed under controlled conditions to initiate and maintain a reaction that produces chlorine gas in the anode chamber and hydrogen gas and a solution of sodium hydroxide in the cathode chamber. The anode and cathode chambers are separated by a chemically-resistant ion-exchange membrane permeable only to positively charged ions.

Abstract: Hydrogen sulfide is removed from a gaseous stream by contacting the stream with an aqueous solution of ferric ion chelated with an aminopolycarboxylic acid at a pH of 3.5 to 5, whereby hydrogen sulfide is oxidized to elemental sulfur and chelated ferric ion is reduced to chelated ferrous ion. The solution also contains ammonia or an aliphatic, alicyclic, or heterocyclic primary or secondary amine in a sufficient proportion to maintain chelated ferrous ion in solution at a pH of 3.5 to 5. The chelated ferric ion is regenerated by contacting the solution with a gas containing elemental oxygen.

Abstract: A process for the simultaneous removal of sulfur oxides and nitrogen oxides from power plant stack gases comprising contacting the stack gases with a supported iron oxide catalyst/absorbent in the presence of sufficient reducing agent selected from the group consisting of carbon monoxide, hydrogen, and mixtures thereof, to provide a net reducing atmosphere in the SO.sub.x /NO.sub.x removal zone. The sulfur oxides are removed by absorption substantially as iron sulfide, and nitrogen oxides are removed by catalytic reduction to nitrogen and ammonia. The spent iron oxide catalyst/absorbent is regenerated by oxidation and is recycled to the contacting zone. Sulfur dioxide is also produced during regeneration and can be utilized in the production of sulfuric acid and/or sulfur.