Regeneration of strong-base anion-exchange resins by sequential chemical displacement
US6448299B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Jan 25, 2000 |
| Grant date | Sep 10, 2002 |
| Priority date | — |
| Expiry date | Jan 25, 2020 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB01J49/57
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
A method for regenerating strong-base anion exchange resins utilizing a sequential chemical displacement technique with new regenerant formulation. The new first regenerant solution is composed of a mixture of ferric chloride, a water-miscible organic solvent, hydrochloric acid, and water in which tetrachloroferrate anion is formed and used to displace the target anions on the resin. The second regenerant is composed of a dilute hydrochloric acid and is used to decompose tetrachloroferrate and elute ferric ions, thereby regenerating the resin. Alternative chemical displacement methods include: (1) displacement of target anions with fluoroborate followed by nitrate or salicylate and (2) displacement of target anions with salicylate followed by dilute hydrochloric acid. The methodology offers an improved regeneration efficiency, recovery, and waste minimization over the conventional displacement technique using sodium chloride (or a brine) or alkali metal hydroxide.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.