Composition for catalytic removal of hydrogen sulfide from gases

Abstract

A composition for use in an oxidation-reduction process for effecting the catalytic oxidation of hydrogen sulfide gas comprising a water soluble ferric iron salt and at least two iron chelating agents, preferably as an alkaline aqueous chelated iron solution, with at least one of said iron chelating agents being an amine compound selected from the group consisting of polyamino polycarboxylic acids, polyamino alkyl polycarboxylic acids, polyamino hydroxyalkyl polycarboxylic acids, and poly(phosphonoalkyl) amines, and their alkali metal salts, such as the sodium salt of ethylenediamine tetraacetic acid, and another of said iron chelating agents being selected from the group of polyhydroxy compounds consisting of monosaccharides, disaccharides, reduced monosaccharides, reduced disaccharides, monosaccharide acids, disaccharide acids, and their alkali metal salts, such as sorbitol. An alkaline aqueous chelated iron solution is prepared by dissolving a water soluble ferric iron salt in water, adding to the solution the required amine-type and polyhydroxy-type iron chelating agents, and to this solution is added an alkaline material, such as sodium hydroxide or sodium carbonate, to provide a concentrate which can be diluted with water as required to obtain an operating solution having the desired pH and iron content for a selected process.