title: Kinetics of phase separation for polyethylene glycol-phosphate two-phase systems.
abstract: Phase separation times for polyethylene glycol (PEG)-4000-phosphate aqueous two-phase systems were studied, for small scale (5-g) and large scale (1300-g) systems, as a -function of the stability ratio. Profiles of dispersion height for both large and small scale systems were represented as a fraction of the initial height and were found to be independent of the geometrical dimensions of the separator. Furthermore, by plotting time as a fraction of the initial height the total time of separation can be calculated for a given height of system at a particular stability ratio. This generalization is important for the design of large scale aqueous two-phase separators. Phase separation times were also found to be dependent on which of the phases is continuous. A characteristic change in phase separation time was also observed at the phase inversion point (i.e., where the dispersed phase changes to a continuous phase and vice versa) and this point tends toward higher volume ratios as the tie-line length (TLL) is increased. Furthermore, the phase inversion point at each TLL corresponds to a fixed phosphate concentration.
authors.affiliation: Biochemical Engineering Laboratory, The University of Reading, Reading, England.
authors.forename: A
authors.initials: A
authors.lastname: Kaul
authors.forename: R A
authors.initials: RA
authors.lastname: Pereira
authors.forename: J A
authors.initials: JA
authors.lastname: Asenjo
authors.forename: J C
authors.initials: JC
authors.lastname: Merchuk