2013 R&D 100 Winner
Switchable Polarity Solvents Forward OsmosisThe availability of fresh, clean water remains a significant challenge as the world’s population grows. Osmosis is an effective, proven way to accomplish this, but concentrated solutions have presented difficulty. Idaho National Laboratory’s Switchable Polarity Solvent Forward Osmosis (SPS FO) process leverages the switching qualities of specialized thermolytic salts to purify water from extremely concentrated solutions. Simple and economical, SPS FO may pass a feed stream through a low-energy pretreatment filtering process to remove large particles, unless the source quality permits entering it directly into a forward osmosis (FO) loop. Using a draw solution that contains the salts, the SPS FO uses the higher pressure created by the solute to draw water through a specialized semi-permeable membrane to separate it from the feed. The FO membrane is designed to allow water to pass from the feed solution to the draw solution, while all other materials are retained in the feed. This dilutes the draw solute. Then, the diluted solute is exposed to low-grade heat, which causes the salts to release carbon dioxide and switch to an oily insoluble material that can be easily separated from water.

Water purification technology

Idaho National Laboratory

Development Team

The Switchable Polarity Solvents Forward Osmosis Development Team from Idaho National Laboratory
Aaron Wilson, Principal Developer
Frederick Stewart
Mark Stone