Culligan International Company

Frank A Brigano

Arthur Katzakian

Charles E Grix

Donald C McGehee

Stanley F Rak

William J Soucie

Processes for deionization and demineralization of a fluid containing ions comprising: (a) Loading an amine or ammonia buffer onto a first weakly acidic cation exchange resin to occupy cation exchange sites and to form a first bed comprising a first amine-buffered resin; (b) Passing said fluid containing ions through said first bed comprising said first amine-buffered resin and exchanging cations of said fluid for amine cations of said first amine-buffered resin to form a first effluent comprising an anion-buffer salt complex; (c) Passing said anion-buffer salt complex through a first weakly basic anion exchange resin where an anion portion of said anion-buffer salt complex is split from said anion-buffer salt complex by adsorption of said anion portion onto said weakly basic anion exchange resin to form a second effluent comprising buffer in free hydrated base form; (d) Passing said buffer in free hydrated base form to a second weakly acidic cation exchange resin where said buffer loads onto said second weakly acidic cation exchange resin as in step (a) and repeating the process of steps (b)-(d); and (e) Regenerating said first weakly acidic cation exchange resin with an organic acid.

Processes for deionization and demineralization of fluids

Processes for deionization and demineralization of a fluid containing ions comprising:

The method of purifying spent brine from the regeneration of ion exchange resin, for example resin in water softeners. The method comprises acidifying the spent brine to a pH of less than 3 with an acid other than sulfuric acid, which acid is preferably chosen from at least one acid which forms a calcium salt that is more water soluble than calcium sulfate. One passes the brine through a nanofiltration membrane to purify the brine by separating from it a waste stream which comprises the majority of the polyvalent ions present, so that the purified brine has most of its contaminating polyvalent ions removed.

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Hoffman Estates, IL, United States of America

Frank A Brigano