Caption title. At head of title: Project summary. Distributed to depository libraries in microfiche. "May 1987." "EPA/600-S2-87-020."

"The feasibility of using crosslinked gels in a reversible process for extracting pure water from aqueous waste solutions has been investigated. It has potential for concentrating waste streams that contain hazardous chemicals. Near critical gels have been developed that swell and collapse as a function of process conditions. At low temperature or high pH, these gels swell by absorbing water. During swelling, they exclude larger solutes, including many hazardous materials. Solutes and colloidal pollutants thus may be concentrated to facilitate treatment and disposal. The gels are made from water soluble monomers; they can be easily regenerated by warming or by adding acid to release the purified water. The collapsed gels are separated by filtration and reused. In this study gels have been contacted with solution containing a wide range of different molecular weight solutes and colloids to determine water extraction capacity and efficiency of solute rejection."