Acoustic demixing of aqueous two-phase systems

<p align="justify">Aqueous two-phase systems demix slowly due to similar physical properties. This is one of the major
drawbacks for their adaptation for industrial scale
extraction of enzymes. In the present work, a method to
accelerate the demixing rates of these systems, employ-
ing a traveling acoustic wave ®eld is reported for the ®rst
time. Phase-demixing for three systems, viz. polyethyl-
ene glycol (PEG)/sodium sulfate, PEG/potassium
phosphate and PEG/maltodextrin were studied. The
acoustically assisted process decreased the demixing time
signi®cantly (about 2- to 3-fold in PEG/salt systems and
about 2-fold in the PEG/maltodextrin system), com-
pared to that in gravity alone. Ultrasonication appar-
ently enhanced the coalescence of the dispersed phase
droplets due to the mild circulation currents it caused in
the dispersion. This in turn enhanced the rate of
demixing due to the increased migration velocity of the
larger droplets.</p>