Abstract: A semipermeable membrane suitable for reverse osmosis applications is prepared by interfacially reacting on a support an aromatic polyamine containing at least three and, preferably, four aromatic nuclei with a polyfunctional amine-reactive compound such as an aromatic polyacyl halide.

Abstract: High flux semipermeable membranes which comprises the polymerized reaction product within and/or on a porous support backing material may be prepared by contacting the porous support such as a polysulfone with an aqueous solution of a polyamine which may, if so desired, contain a polar aprotic solvent not reactive with the amines, a polyhydric compound and an acid acceptor. The surface of the coated support is freed of excess solution and thereafter contacted with an organic solution of a polyacyl halide for a period of time sufficient to form a polymerized reaction product within and/or on the support material. The resulting composite is then treated with a hydroxy polycarboxylic acid, polyaminoalkylene polycarboxylic acid, suffonic acid, amine salts of acids, amino acid, amino acid salt, polymeric acid and inorganic acid, before drying of the membrane. This will enable the membrane to be stored in a dry manner prior to use thereof in a separation process.

Abstract: Chlorine-resistant semipermeable membranes which comprise an interfacial polymerized reaction product composite on a porous support backing material may be prepared by contacting a porous support material such as polysulfone with an aqueous solution of an aromatic polyamine, said aqueous solution containing a polyhydric compound and an acid acceptor. The coated support material is then contacted with an organic solvent solution of an aromatic polycarboxylic acid halide for a period of time sufficient to form an interfacial polymerized reaction product on the surface of the support material. The resulting composite is then post treated by washing with an alkaline compound, leaching with sodium bisulfite and treating the leached composite with a polyhydric compound. The resultant membrane composite may be used in separation processes such as the desalination of brackish or sea water, trhe membrane being resistant to attack by chlorine which is present in the water.

Abstract: Alcoholic beverages may be passed through a reverse osmosis system to form a permeate and a retentate. The permeate will comprise mainly alcohol and water and will be removed as will a minor portion of the retentate which is recovered as product. The major portion of the retentate is recycled back to the reverse osmosis system to admix with fresh beverage and added water. The product will comprise a beverage containing a lower alcoholic content than was possessed by the fresh beverage. The semipermeable membrane which is utilized in the reverse osmosis process will possess a chloride ion rejection rate greater than about 80% at 400 pounds per square inch net pressure.

Abstract: Low alcohol content beverages may be obtained by passing a high alcohol content beverage through a reverse osmosis system to form a permeate and a retentate. The permeate comprising mainly alcohol and water is removed. A minor portion of the retentate is recovered as product while a major portion of the retentate is recycled back to the reverse osmosis system to admix with fresh beverage and added water.