The Dow Chemical Company

Robert R Grinstead

Wilmonte A Nasutavicus

H Hunter Paalman

Kenneth C Jones

The invention is a concentric microporous tubular membrane device containing ion exchange or absorbent particles within the annular region formed by the concentric microporous tubular membranes. The device is useful for carrying out ion exchange or absorbent processes such as scavenging metals or organics from wastewater.

Concentric tubular membrane device and process useful in ion exchange or

The invention relates to a cyclic process for the removal of NO.sub.x and SO.sub.x from a gas stream containing NO.sub.x and SO.sub.x. The gas stream is scrubbed with an aqueous reaction solution containing an organic, water-soluble, polymeric chelate containing a polyvalent metal ion. The NO.sub.x is absorbed and in the presence of SO.sub.x, the imidodisulfonate is formed. The aqueous reaction solution containing chelate and imidodisulfonate is contacted with a first membrane separation means, wherein calcium oxide is added to the first permeate stream, resulting in the precipitation of calcium sulfite. The calcium sulfite is filtered from the first permeate stream, the first permeate stream combined with the first non-permeate stream, and the combined stream contacted with a second membrane separation means which removes a portion of the water and other low molecular weight materials, with recycle of the remaining non-permeate stream containing chelate to the scrubber. Water-soluble alkali is added to the process as needed.

Cyclic process for the removal of NO.sub.x and SO.sub.x from gas streams

The present invention relates to a cyclic continuous process and a composition for the removal of hydrogen sulfide from a variety of sour gas streams. The sour gas stream is contacted with an aqueous solution of a water-soluble organic polymeric chelate containing an oxidizing polyvalent metal, e.g., Fe(III). The sulfur in the hydrogen sulfide is converted to elemental sulfur and the iron in the polymeric chelate is reduced. The process includes removal of the elemental sulfur, and an inexpensive method for removing water and excess low molecular weight materials, e.g., materials having molecular weights below 500, preferably using ultrafiltration or dialysis regeneration and recycle of the reactive polyvalent metal.

Process for the removal of H2S from fluid streams using a water soluble

The present invention relates to a cyclic continuous process and a composition for the removal of hydrogen sulfide from a variety of sour gas streams. The sour gas stream is contacted with an aqueous solution of a water-soluble organic polymeric chelate containing an oxidizing polyvalent metal, e.g., Fe(III). The sulfur in the hydrogen sulfide is converted to elemental sulfur and the iron in the polymeric chelate is reduced. The process includes removal of the elemental sulfur, and an inexpensive method for removing water and excess low molecular weight materials, e.g., materials having molecular weights below 500, preferably using ultrafiltration or dialysis, regeneration and recycle of the reactive polyvalent metal.

Process for the removal of H.sub.2 S from fluid streams using a water

The present invention relates to a cyclic continuous process and composition for the removal of NO and SO.sub.2 from a variety of fluid streams. A fluid stream containing NO and SO.sub.2 is contacted with an aqueous solution of water-soluble organic polymeric chelate containing a polyvalent metal, e.g., Fe (II). The NO is catalytically absorbed and in the presence of SO.sub.2, the imidodisulfonate is formed. Optionally, a reducing agent, such as sodium hydrogen sulfide, is added to maintain the polyvalent metal in the reduced state. The process next includes removal of the imidodisulfonate formed. The separation of water and low molecular weight materials and products, e.g. molecular weight below 500, usually occurs by ultrafiltration or dialysis, with recycle and re-use of the polyvalent metal chelate.

Process for the removal of NO from fluid streams using a water soluble

The present invention relates to a cyclic continuous process for the removal of boron ion from aqueous streams. An aqueous stream in contacted with an aqueous solution of a water-soluble organic polymeric chelant. The boron ion is absorbed and chelated. The separation of water and smaller molecules is accomplished by separation means such as ultrafiltration or dialysis. The concentrated aqueous solution is then treated with dilute aqueous mineral acid, followed by the released boron. The chelant is then recycled and reused. Preferred chelants are polymers having pendant N-alkylglucamine or derivative thereof or trihydroxyalkylamines or derivatives thereof. A preferred chelant is N-methylglucamine attached to a commercial FIBRABON 35 polymer using a -2-hydroxypropyl linkage. Additional preferred embodiments are those polymers having trihydroxymethyl amine in the pendant group attached to a FIBRABON 35 polymer backbone. The process is useful to remove toxic boron from agricultural water, industrial waters, waste-water sewage, oil well brine, and the like.

Process for removing boron ions from aqueous solutions

The present invention relates to a cyclic continuous process and composition for the removal of metal ions, particularly transition metal ions, from aqueous solutions a fluid stream containing the metal ions is contacted with an aqueous solution of a water soluble organic polymeric chelant. The metal is chelated by the chelant: The separation of water and low molecular weight products (molecular weight less than 500) is accomplished usually by dialysis or ultrafiltration. The metal ion is then released using dilute mineral acid and collected. The water-soluble chelant is then recycled. The metal ions chelated removed included iron, cobalt, copper, vanadium, cadmium, nickel, zinc, lead, and aluminum. A preferred chelant is one having a pendant pyridine group in conjunction with alkyl amine groups, e.g., --N(R)--CH.sub.2 --C.sub.5 H.sub.4 N, where R is alkyl.

Process and composition for removal of metal ions from aqueous solutions

The present invention relates to a cyclic continuous process and compositon for the removal of NO and SO.sub.2 from a variety of fluid streams. A fluid stream containing NO and SO.sub.2 is contacted with an aqueous solutin of water-soluble organic polymeric chelate containing a polyvalent metal, e.g., Fe (II). The NO is catalytically absorbed and in the presence of SO.sub.2, the imidodisulfonate is formed. Optionally, a reducing agent, such as sodium hydrogen sulfide, is added to maintain the polyvalent metal in the reduced state. The process next includes removal of the imidodisulfonate formed. The separation of water and low molecular weight materials and products, e.g. molecular weight below 500, usually occurs by ultrafiltration or dialysis, with recycle and re-use of the polyvalent metal chelate.

Process for the removal of NO from fluid streams using a water-soluble

Resins bearing picolylamine moieties selectively adsorb iodide ions from acidic aqueous solutions. The iodide can be readily eluted from the resin with base. Particularly useful resins are obtained by reacting chloromethylated styrene-divinylbenzene copolymers with N-(2-hydroxyethyl)-2-picolylamine or bis-(2-picolyl)amine.

Iodine adsorption via picolylamine ion exchange resins

An extractant system comprising (a) a high molecular weight alkylaromatic sulfonic acid and (b) a chelating amine having a pKa of from about 3 to about 9 in a solvent which is essentially immiscible with water, said system being useful for the selective extraction of desired metals, e.g., cobalt, nickel or copper ions from aqueous acidic ore leach liquors.

Metallurgical extractant system

Extraction of copper, nickel and cobalt using alkylaromatic sulfonic

Nitro-substituted 2-(2-hydroxyphenyl)benzoxazoles of the formula ##STR1## wherein one of R.sup.3 and R.sup.4 is --NO.sub.2 and the other is --H, --NO.sub.2 or alkyl of 1 to 20 carbons and R.sup.1 and R.sup.2 independently are --H or alkyl of 1 to 20 carbons, with the proviso that R.sup.1, R.sup.2, R.sup.3 and R.sup.4 contain a total of at least 7 carbons, are acidic, oil soluble compounds having utility for extraction of copper from strongly acidic ore leaches. Excellent selectivity for copper over iron is exhibited by the subject compounds.

Nitro-substituted benzoxazoles having utility as metallurgical

New chelate exchange resins capable of selective recovery of copper, nickel, and other valuable metals from an acidic aqueous leach liquor are prepared by reacting a crosslinked haloalkyl polymer matrix resin (I) with certain aminopyridines (II) to give a resin (III) ##STR1## with pendent methyleneaminopyridine groups attached to the matrix resin. Particularly useful resins are obtained by reacting chloromethylated styrene-divinylbenzene copolymer beads with an aminomethylpyridine, such as 2-picolylamine, N-methyl-2-picolylamine, N-(2-hydroxyethyl)-2-picolylamine, N-(2-methylaminoethyl)-2-picolylamine, or bis-(2-picolyl)amine. At a typical copper ore leach liquor pH of about 2, the picolylamine resins will absorb 15-30 mg copper/ml resin with a 5-10 fold selectivity for copper over ferric iron.

Water-insoluble chelate exchange resins from aminopyridines and process

Water insoluble chelate exchange resins having a crosslinked polymer

Mono or dicarboxylic acids containing from two to four carbon atoms are extracted from dilute aqueous solutions with an organic liquid comprising one or more of the following extractants: dialkyl alkyl phosphonates, alkyl dialkyl phosphinates, trialkyl phosphine oxides, dialkyl alicyclic amidophosphates, dialkyl sulfoxides and tetralkyl ureas. An improved method for removing carboxylic acid contaminants from aqueous effluents or recycle streams is provided.

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Walnut Creek, CA, United States of America

Robert R Grinstead