摘要 |
A process for removing a solvent from a source solution, said process comprising a) contacting the source solution with one side of a selectively permeable membrane, b) contacting a draw solution having a higher osmotic pressure (higher solute concentration) than the source solution with the opposite side of the membrane, such that solvent from the source solution passes across the membrane to dilute the draw solution by direct osmosis, c) removing solvent from the diluted draw solution to regenerate the draw solution, and d) recycling the regenerated draw solution to step a), characterised in that a portion of the draw solution is discarded or treated before and/or after the draw solution is regenerated in step c) so as to reduce the concentration of any solute species present in the draw solution from the source solution.
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