Abstract
Salt in polyethylene glycol (PEG)/salt aqueous two-phase systems was excluded by PEG and concentrated in the solvent volume available for dissolution of salt (PEG-free solvent). The concentration of salt in the PEG-free solvent of the PEG-rich phase was the same as that at the critical point regardless of the compositions of the PEG/salt two-phase systems. This explained that the phase separation of PEG/salt two-phase systems occurs when the concentration of salt in the PEG-free solvent reaches its solubility limit. The concentration of salt required in the PEG-free solvent for the phase separation was lower with higher molecular weight of PEG. The solubility of salt in the PEG-free solvent decreased with increases in the molal surface tension increment of salt. The solubility limit of salt in the PEG-free solvent was 0.93 M for ammonium sulfate, 0.77 M for potassium phosphate, 0.75 M for sodium tartrate, 0.67 M for sodium phosphate, and 0.53 M for potassium citrate.
Original language | English |
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Pages (from-to) | 181-191 |
Number of pages | 11 |
Journal | Physics and Chemistry of Liquids |
Volume | 38 |
Issue number | 2 |
DOIs | |
Publication status | Published - 2000 |
Keywords
- Aqueous two-phase system
- Excluded volume
- PEG
- Phase separation
- Solubility of salt
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Physical and Theoretical Chemistry
- Materials Chemistry