Chemically Selective Membrane Separations

Size selective membrane separations have demonstrated exemplary energy-efficiencies. The success of seawater desalination by reverse osmosis (RO) is a clear example of the energy savings and sustainability that can be realized by replacing traditional separation processes with a size-selective membrane separation. At its inception, RO desalination consumed almost three times more energy than equivalent thermal desalination methods such as multistage flash distillation (MSF). However, over the past forty years, due to fundamental technological advances, the energy demand of seawater RO has fallen dramatically; and it now requires about half the energy of MSF. Unfortunately, the reliable performance of chemically selective membranes lags behind significantly.

This gap in performance needs to be addressed if sustainable membrane separations are to be used to isolate similarly sized molecules (e.g., chiral molecules) or to remove dilute contaminants (e.g., endocrine disrupting chemicals) from drinking water. In order to accomplish this, we will focus our efforts on the fundamental thermodynamic and transport phenomena of chemically selective permeation through polymeric membranes before applying that knowledge toward engineering a high performance membrane for directed applications. By looking closely into the structure-property-performance relationships of model systems with a systematic combination of transport testing and materials characterization, we will be able to answer key fundamental questions about what physical and chemical membrane properties (e.g., solute-membrane affinity and membrane pore size) enable the chemically selective transport of solutes through polymeric membranes.