Forming a treated switchable polymer and use thereof in a forward osmosis system
AssigneesQueen's University at Kingston, Forward Water Technologies
InventorsPhilip G. Jessop, Michael Cunningham, Pascale Champagne, Sarah Ellis, Ryan Dykeman, Charles Honeyman, Amy Holland, Tobias Robert, Bhanu Mudraboyina
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Abstract
A forward osmosis system is disclosed which use a polymer switchable between a neutral form and an ionized form. The switchable polymer has a higher osmotic pressure at the ionized form than the neutral form, the ratio between the former and the latter is ≥2. There is also disclosed a method for treating the polymer such that the ratio is improved. Use of polymers for forward osmosis is also disclosed.
Claims41
A process of forming a treated switchable polymer, comprising:
- providing a switchable polymer that is switchable between a first form and a second form, the switchable polymer comprising switchable moieties, each switchable moiety being switchable between a neutral form associated with the first form of the switchable polymer, and an ionized form associated with the second form of the switchable polymer,
- the switchable polymer
- (i) having ≥3 mmol switchable moieties per gram of switchable polymer,
- (ii) having a pKaH of about 7 to about 14, and
- (iii) being resistant to hydrolysis;
- treating the switchable polymer to remove non-polymeric and/or oligomeric contaminants;
- and
- forming a treated switchable polymer that is switchable between a third form and a fourth form, the neutral form of each switchable moiety being associated with the third form of the treated switchable polymer, and the ionized form of each switchable moiety being associated with the fourth form of the treated switchable polymer,
- the third form of the treated switchable polymer having a first osmotic pressure in aqueous solution, and the fourth form of the treated switchable polymer having a second osmotic pressure in aqueous solution, the ratio of the second osmotic pressure divided by the first osmotic pressure being ≥2,
- the treated switchable polymer
- (iv) being substantially water soluble in the fourth form.
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A forward osmosis system, comprising:
- a draw solution comprising a switchable polymer switchable between a neutral form and an ionized form, wherein
- the neutral form is associated with a first osmotic pressure,
- the ionized form is associated with a second osmotic pressure, and
- the second osmotic pressure is higher than the first osmotic pressure;
- and
- a feed solution in fluid communication with the draw solution, the feed solution comprising a feed solvent that is the same as the solvent of the draw solution, and the feed solution being separated from the draw solution by a semipermeable membrane that is selectively permeable to the solvent,
- wherein at least a portion of the feed solvent permeates from the feed solution to the draw solution when the polymer is in the ionized form to produce a concentrated feed solution and a diluted draw solution,
- wherein a ratio between the second osmotic pressure and the first osmotic pressure is ≥2.
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A process for treating a switchable polymer switchable from a neutral form associated with a first osmotic pressure and an ionized form associated with a second osmotic pressure such that a ratio between the second osmotic pressure and the first osmotic pressure is increased, the process comprising treating the switchable polymer to remove non-polymeric and/or oligomeric contaminants.
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Dependencies are inferred from the claim text.