Semipermeable composite membranes, their manufacture, and use
US4753725A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 11, 1981 |
| Grant date | Jun 28, 1988 |
| Priority date | — |
| Expiry date | Sep 11, 2001 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB01D2323/30
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
Semipermeable composite membranes containing on one surface of a porous support a superficial thin film having semipermeable properties. The film contains polyvinyl alcohol (PVA)/polyvinyl alcohol-copolymers (PVA-copolymers) modified by at least radicals containing ionizable groups are provided. The modification steps comprise e.g. reacting PVA/PVA-copolymer films with PA0 (a) a monomeric organic compound containing at least two functional groups, PA0 (b) a linear or branched polyfunctional oligomer or polymer, and PA0 (c) a compound containing cross-linking and ionizable groups. The novel membranes show good mechanical, temperature and pH-stabilities and are suitable, for example, for separating monovalent ions of low ionic weight from polyvalent ions of low or high ionic weight or for separating ionic compounds from non-ionic compounds or from ionic compounds which have a different molecular weight or opposite charge. They can be used for example for separating salts from organic compounds (dyes) or in waste-water treatment.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.