Use of inorganic ammonium cation salts to maintain the flux and salt rejection characteristics of reverse osmosis and nanofiltration membranes during drying
US5658460A · kind A · utility
48Cited by
8References
6Claims
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Key dates
| Filing date | May 7, 1996 |
| Grant date | Aug 19, 1997 |
| Priority date | — |
| Expiry date | May 7, 2016 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB01D69/1251
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
To prevent the deterioration of the flux and salt rejection characteristics of polyamide, thin-film, composite reverse osmosis membranes when subjected to relatively high temperature drying conditions, an unsubstituted inorganic ammonium cation salt of an acid is incorporated into the process of manufacture. The ammonium salt can be introduced into the process either before or after the membrane is formed by interfacial polymerization so long as it is added before the membrane is heated.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.