Scientists discover new behavior of membranes that could lead to unprecedented separations

Until now, scientists believed there was a limit to the sharpness of the separation of solutes in water or other fluids that they could achieve with a porous membrane, not only because of variations in pore size but also because of a phenomenon called hindered transport – the internal resistance of the fluid as a solute tries to go through a pore. Now, researchers from the U.S. Department of Energy’s Argonne National Laboratory and the University of Chicago have shown that by using an isoporous membrane, in which all the pores are the same size (approximately 10 nanometers), and by giving the solutes multiple chances to get through the pores, it is possible to surmount hindered transport limitations.