Lehigh University

Surapol Padungthon

Arup K SenGupta

Michael German

Jinze Li

The present invention includes a novel salt-free water softening method that utilizes an exchange medium (such as a gel exchange polymer, a macroporous exchange polymer, or an inorganic cation exchanger) that is pre-loaded with a polyvalent cation that has low solubility in aqueous phase at nearly neutral pH. The method of the invention does not require use of a sodium salt or mineral acid in the regeneration of the exchange medium.

Ion exchange methods for treating water hardness

Polymeric anion exchanger are used as host materials in which sub-micron sized hydrated Zr(IV) oxides (HZrO) particles are irreversibly dispersed within the ion exchange medium, such as beads or fibers. The HZrO can be impregnated into the pore structure of resin by mixing the parent anion exchange resin with zirconium solution prepared by pre-calcined zirconium oxide dissolved in concentrated mixture of alcohol and acid, and then followed by precipitation of HZrO particles within the resin by using alkaline solution. Since the anion exchangers have positively charged such as quaternary ammonium functional groups, anionic ligands such as arsenate, fluoride can transport in and out of the gel phase without subjected to the Donnan exclusion effect. Consequently, anion exchanger-supported HZrO submicron particles exhibit significantly greater capacity to remove arsenic and fluoride in comparison with parent anon exchange resins. Known cation exchange resins as support materials do not offer high arsenic or fluoride removal capacity.

Hybrid anion exchanger impregnated with hydrated zirconium oxide for selective removal of contaminating ligand and methods of manufacture and use thereof

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Bethlehem, PA, United States of America

Surapol Padungthon