Ion expulsion ultrafiltration method
AssigneeThe Board of Regents of the University of Oklahoma
InventorsSherril D. Christian, Edwin E. Tucker, John F. Scamehorn
Life of this patent
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Abstract
A method for reducing the concentration of target co-ions in a liquid feed mixture comprising target co-ions and counter-ions by adding a colloid such as a polyelectrolyte or surfactant comprising a colloidal ion and colloidal counter-ions to the feed mixture wherein the colloidal ion has the same type of charge as the target co-ion. The feed mixture containing the colloid is filtered through an ultrafiltration membrane having pores small enough to block the passage of the colloidal ion.
Claims20
A method for reducing the concentration of target co-ions in a retentate of a liquid feed mixture comprising dissociated target co-ions and counter-ions, wherein the target co-ions and the counter-ions are oppositely charged, comprising:
- adding to the feed mixture a sufficient amount of a colloid having a molecular weight greater than 10,000 comprising at least one colloidal counter-ion and a highly charged colloidal ion, wherein the colloid at least partially dissociates in the feed mixture to create an excess of free colloidal counter-ion to target co-ions, the colloidal ion being characterized by the same type of charge as the target co-ion and the colloidal counter-ion having the same type of charge as the counter-ion, and
- wherein the target co-ion is sized to pass through the pores of an ultrafiltration membrane and the colloidal ion is sized such that the colloidal ion cannot pass through the pores of the ultrafiltration membrane;
- and
- filtering at least a portion of the target co-ions through the ultrafiltration membrane.
A method for recovering a target co-ion from a liquid feed mixture comprising dissociated target co-ions and counter-ions, wherein the target co-ions and the counter-ions are oppositely charged, comprising:
- adding to the feed mixture a sufficient amount of a colloid having a molecular weight greater than 10,000 comprising a highly charged colloidal ion and a colloidal counter-ion, wherein the colloid at least partially dissociates in the feed mixture to create an excess of free colloidal counter-ion to target co-ions, the colloidal ion being characterized as having the same type of charge as the target co-ion and the colloidal counter-ion having the same type of charge as the counter-ion;
- and
- filtering at least a portion of the target co-ions and a portion of the feed mixture through an ultrafiltration membrane having pores, wherein the portion of the target co-ion and the portion of the feed mixture passing through the pores of the membrane forms a permeate solution, and
- wherein the target co-ion is sized to pass through the pores of the ultrafiltration membrane and the colloidal ion is sized such that the colloidal ion cannot pass through the pores of the ultrafiltration membrane;
- and
- recovering the target co-ion from the permeate solution.
Dependencies are inferred from the claim text.