Electrically Conducting Membranes for Water Treatment Applications
We have developed a range of electrically conducting carbon nanotube-polymer composite membranes suitable for most membrane-based water treatment applications, including reverse osmosis, nanofiltration, ultrafiltration, forward osmosis, and membrane distillation. By applying an external electrical potential to the membrane surface we can prevent many fouling events, including biofouling, organic and colloidal fouling, and mineral scaling. In addition, we take advantage of the membrane's inherent electrical conductivity to drive a range of electrochemcial reactions, which can be used to destroy/transform aqueous contaminants. We are using our membranes to treat industrial and domestic wastewater, with the goal of creating a sustainable wastewater recycling process that produces clean, safe and abundent water at an affordable rate.
The separation of oil, and in particular, emulsified oil, from water remains one of the most challenging water treatment processes. This separation is critical for a range of industries, including environmental spill remediation (such as during the Macondo oil spill), wastewater treatment, and industrial wastewater recycling. While effective at removing even the smallest emulsified oil droplets, membranes tend to foul very rapidly, making them difficult to use for this separation process. We have developed several techniques that enable us to separate many kinds of oil from water using membrane technology. We are continuously investigating new methods and contaminated waters, and applying our knowledge towards finding innovative solutions.
New Membrane Materials Through Electropolymerization
Electropolymerization, where a polymerization reaction is driven by the application of an electrical potential to a conductive surface, is a well-established technique that has been used extensively in the fabrication of sensors for small molecules, ions, and gases. Electropolymerization can facilitate the formation of many types of polymers, including polyethers, polyesters, and polyamides, from a wide variety of monomer precursors. Depending on monomer choice, the electropolymerized material can form either electrically inert, thin, dense and smooth polymers ideally suited for RO and NF applications, or electrically active, porous and hydrophilic polymers suitable for UF or MD applications. In this project, we explore the use of electropolymerization for creating smooth, dense, oxidant-resistant polymers that maintain the transport properties necessary for RO and NF processes, including high salt rejection and high water flux, as well as highly porous reactive polymers useful in UF and MD applications.
Material Fabrication and Characterization
We are continuously developing new membrane materials with improved physical and chemical properties for a variety of separation methods, including membrane distillation, forward osmosis, gas separations, and packed columns. We use a range of surface and electrochemical analytical tools to characterize these materials, with the goal of solving some of the most pressing problems facing separation processes.
In addition to small-scale material fabrication and testing, we have developed the means to form and test pilot-scale membranes (in flat sheet configuration), and are engaged in piloting the application of electrically conducting UF and NF membranes for industrial wastewater treatment, and in a seperate project, demonstrating the use of Pickering emulsions coupled to UF membranes for oil/water separations under arctic conditions.