| Patent Number |
Title Of Patent |
Date Issued |
| 5658460 |
Use of inorganic ammonium cation salts to maintain the flux and salt rejection characteristics o |
August 19, 1997 |
| 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 th |
| 4964998 |
Use of treated composite polyamide membranes to separate concentrated solute |
October 23, 1990 |
| A method of separating water of reduced concentration of a selected solute via reverse osmosis, wherein the selected solute is sulfuric acid, sodium hydroxide, isopropanol, sodium nitrate or another solute having a much higher solute passage than sodium chloride. The reverse osmosis memb |
| 4960518 |
Treatment of composite polyamide membranes with compatible oxidants |
October 2, 1990 |
| A reverse osmosis membrane having improved rejection of sulfuric acid and/or isopropanol is described. The membrane is prepared by treating a crosslinked, polyamide discriminating layer with a compatible oxidizing reagent, such as peracetic acid, periodic acid or chloramine, whereby the |
| 4960517 |
Treatment of composite polyamide membranes via substitution with amine reactive reagents |
October 2, 1990 |
| A reverse osmosis membrane having improved rejection of sulfuric acid and/or isopropanol is described. The membrane is prepared by treating a crosslinked, polyamide discriminating layer with an amine-reactive reagent selected from a carboxylic acid ester, a carboxylic acid anhydride, an |
| 4895661 |
Alkali resistant hyperfiltration membrane |
January 23, 1990 |
| A novel hyperfiltration membrane and process for making the same is described. The membrane is useful for processing copper electroless solutions to concentrate for re-use salts of chelating agents. The membrane can be prepared by crosslinking a water-compatible polymer in the presen |
| 4888116 |
Method of improving membrane properties via reaction of diazonium compounds or precursors |
December 19, 1989 |
| A method of improving the properties of a reverse osmosis membrane having a polyamide discriminating layer containing residual aromatic primary amine groups is described. In this method, the polyamide discriminating layer of the membrane is treated with an aqueous solution of a reagent w |
| 4834886 |
Process for making alkali resistant hyperfiltration membrane and resulting product |
May 30, 1989 |
| A novel hyperfiltration membrane and process for making the same is described. The membrane is useful for processing copper electroless solutions to concentrate for re-use salts of chelating agents. The membrane can be prepared by crosslinking a water-compatible polymer in the presen |
| 4824574 |
Novel water softening process using membranes |
April 25, 1989 |
| A novel water softening membrane and process for making the same is described. The membrane can be prepared by treating a polyamide reverse osmosis membrane with a strong mineral acid followed by treatment with a rejection enhancing agent. The resulting membrane at transmembrane pres |
| 4812270 |
Novel water softening membranes |
March 14, 1989 |
| A novel water softening membrane and process for making the same is described. The membrane can be prepared by treating a polyamide reverse osmosis membrane with a strong mineral acid followed by treatment with a rejection enhancing agent. The resulting membrane at transmembrane pres |
| 4812238 |
Membranes prepared via reaction of diazonium compounds or precursors |
March 14, 1989 |
| An improved reverse osmosis membrane and process for making the same is described. The membrane is prepared by treating a polymer bearing primary amine groups with nitrous acid or a diazonium compound so as to react the resulting diazonium groups with other groups present. The resulting |
| 4765897 |
Polyamide membranes useful for water softening |
August 23, 1988 |
| A novel water softening membrane and process for making the same is described. The membrane can be prepared by treating a polyamide reverse osmosis membrane with a strong mineral acid followed by treatment with a rejection enhancing agent. The resulting membrane at transmembrane pres |
| 4277344 |
Interfacially synthesized reverse osmosis membrane |
July 7, 1981 |
| Good salt rejection and flux characteristics can be obtained with reverse osmosis membranes made from crosslinked, interfacially polymerized aromatic polyamides, particularly poly(arylenepolyamine aromaticpolycarboxylamides) such as poly(phenylenediamine trimesamide). The aromatic po |
| 4259183 |
Reverse osmosis membrane |
March 31, 1981 |
| A composite permselective membrane is prepared by reaction of a film or layer containing cycloaliphatic polyfunctional secondary amines with a triacyl halide or its mixture with a diacyl halide. The membrane is useful in separating components of fluid mixtures or solutions, such as the |
| 4039440 |
Reverse osmosis membrane |
August 2, 1977 |
| A reverse osmosis membrane is prepared by reaction of a film or layer of polyethylenimine with a polyfunctional reagent whose functional groups are capable of reacting with amine groups. The polyfunctional reagent is preferably a water-soluble, aromatic or heterocyclic compound having ac |
