Several liquid-phase extraction technologies employing environmentally beni
gn phase- or micelle-forming polymers in aqueous solution have the potentia
l to replace volatile organic compounds in classical solvent extraction tec
hnologies. The examples reviewed here include aqueous biphasic system's, cl
oud-point extraction, micellar extraction, and thermoseparating polymer sys
tems. The apparent similarities of these systems, their phase-separating pr
operties, and their ability to solubilize a wide variety of solutes ranging
from metal ions, organic compounds, and biologicals are discussed. Some co
mparative data from the literature whereby the solvating power of these sys
tems may be compared to traditional solvents are presented along with new d
ata on the polarity of the phases in typical aqueous biphasic systems. The
need for additional comparative data in this area and the need to demonstra
te the validity of the approach in operational processes are emphasized. A
"toolbox" approach to implementing environmentally benign polymers in clean
separations science and technology could lead to new and better solvent ex
traction systems.