| abstract |
Thermally reversible, amphoteric microbead matrix ion exchange resins of micron size particles of crosslinked, weak acid cation or weak base anion exchange resin embedded in a matrix of a weak ion exchange resin of opposite form are prepared by suspending micron size particles of a weak ion exchange resin in a mixture of monomers which can be converted to a crosslinked matrix polymer, polymerizing the monomers, and then converting the microbead-matrix resin into active ion exchange form with a particle size of about 0.074-4.00 mm. Preferably the resin has microbeads of crosslinked polyacrylic acid embedded in a matrix of polymerized vinylbenzyl chloride - divinylbenzene aminated with dimethyl amine. These amphoteric resins absorb salts from water in a thermally reversible manner with improved resin capacities and kinetics. They have particular utility in the desalination of brackish waters. |