A Low Viscosity, High Conductivity Working Fluid for Economic Water Desalination

Advanced economies across the globe increasingly require sustainable and affordable infrastructure to meet the basic needs of their growing populations. An ongoing challenge for engineers is to address this demand with new and better technologies that are both cost competitive with existing infrastructure but also produce lower environmental impacts over their operational lifetimes. Increasingly, climate change has forced some communities in the United States to consider water security as a key component of their infrastructure investment. In these communities, brackish/sea water treatment is seen as part of a solution to ensure sustainable access to a potable water supply. Existing desalination technologies including reverse-osmosis (RO) membranes, however, suffer from poor scalability and high operation costs. Emerging alternatives include flow-assisted capacitive deionization (FACD). This technology promises a balance between scalability and efficient purification. The enabling feature of FACD is a suspension of conducting particles. These particles provide a continuous electrically percolated network, which is necessary to mediate electron transfer from the current collectors to salt from fresh water. Carbon black is frequently used in this application due to its low cost and its physical properties. Unfortunately, while carbon black can provide the necessary electrical performance, its presence has a detrimental effect on the rheology of the active fluids. In the Richards Laboratory at Northwestern, we are developing a low viscosity, high conductivity working fluid that could replace carbon black and improve the economic viability of this promising technology. In this talk, I will outline our synthetic approach and also highlight two key figures of merit for a successful technology.

BioJeffrey Richards earned his Ph. D. from the Department of Chemical Engineering at the University of Washington working for Dr. Lilo D. Pozzo in 2014. After graduation, Jeffrey had the opportunity to join Dr. Norman Wagner's group at the University of Delaware as a postdoctoral scholar in the Department of Biomolecular and Chemical Engineering before starting as a National Research Council (NRC) Fellow at the NIST Center for Neutron Research in Gaithersburg, MD. Jeffrey joined the Department of Chemical & Biological Engineering in September 2018. His lab focuses on understanding the relationship between microstructure and macroscopic properties of soft matter.