Engineer Introduces Thermally-Reversible Polymer to Desalination

According to, 780 million people lack access to clean water. The need to provide access to clean water is one of the National Academy of Engineering’s Grand Challenges for Engineering.


At noon this Thursday, Sept 12, Dr. Xinying Wang will present “Polymer Assisted Forward Osmosis for Desalination and Water Reuse,” at U of I’s Mechanical Engineering Building, Rm. 218 (1206 W Green St. in Urbana, IL).


This webinar, as part of the ISTC’s Sustainable Technology Seminar Series “Sustainability in Action,” will be broadcast live and also archived on our website for later viewing. If you cannot attend the event at Rm. 218 MEB, you may view the webinar live by registering at: It will also be viewable live at the ISTC Conference Room at 1 Hazelwood Dr., Champaign, IL.


Dr. Wang is a Chemical Engineer at the Illinois Sustainable Technology Center, Prairie Research Institute. The following is his abstract for the seminar:


“Forward osmosis (FO) for dewatering/desalination applications has received increasing interest due to its potential use of low grade thermal energy, ability to operate at low pressure, and  reduced tendency to foul. Developments in FO are primarily focused on two areas: (a) expanding the availability of draw solutions that generate high osmotic pressure; are easily separated from water using physical and/or chemical means; are non-corrosive, nontoxic, and chemically stable; exhibit near neutral pH; and are inexpensive and (b) developing membranes that exhibit high flux and suitable salt rejection under FO conditions. In this presentation we focus on the challenges of draw solution utilization and regeneration.


In this presentation, we will talk about a forward osmosis desalination process that employs a temperature-reversible polymer to recycle the draw solute. In our work, a high concentration MgSO4 solution is used as draw solution. After forward osmosis, the diluted draw solution is mixed with a thermally-reversible polymer, poly (propyleneoxide) –co-poly (ethyleneoxide). This polymer extracts water from the diluted draw solution and the whole solution forms two phases, a polymer-water phase and a concentrated MgSO4 solution phase (bottom). The bottom MgSO4 solution phase is recycled back to the forward osmosis module, while the polymer-water phase is heated above the polymer’s cloudy point (60⁰C) to recycle the polymer and to produce clean water.  Experimental details on the process will be presented.”