Improvements in or relating to the removal of ionizable materials from aqueous solutions such as sugar solutions

摘要

Ion-exchange resins used in the treatment of aqueous liquids may be of the quaternary ammonium type described in Specification 654,706 or may be prepared by haloalkylating polystyrene, preferably with a chloromethyl ether and converting the product to a quaternary ammonium compound by treatment with a tertiary amine, preferably trimethylamine. Other resins which may be used are the cross-linked polymers made by copolymerization of acrylic, methacrylic or maleic acid with a divinyl aromatic compound, preferred resins being those prepared by the suspension copolymerization of from 90 to 97 1/2 parts of acrylic or methacrylic acid with from 2 1/2 to 10 parts of divinyl benzene.ALSO:Ionizable materials are removed from aqueous solutions such as gelatine solutions (see Group V), or from sugar solutions or milk (see Group VI), by passing the liquid through a bed of anion-exchange resin containing quaternary ammonium groups and then through a bed of cation-exchange resin. The quaternary ammonium groups may be attached through methylene groups to aromatic rings in the resin, which may be a styrene polymer or a styrene-divinyl-benzene copolymer. The polar groups of the cation exchange resin may be carboxylic acid groups which may be in a mixed acid and sodium salt form; the resin itself may be a cross-linked polymer of a polymerizable acid, preferably acrylic, methacrylic, or maleic acid; or a copolymer of divinyl benzene and methacrylic acid. The solution may be passed through alternating beds of anion- and cation-exchange resin. Specification 654,706 is referred to