Dr. Xiao Su, University of Urbana-Champaign

Host: Dr. Anderson

Innovations in separation technologies are critical to our supply-chain security, and to guarantee clean air and water. Redox-electrochemistry, which has been key to energy storage and sensing technologies, can play an important role in enabling of selective electrochemical separations. Electrochemical separations can promote sustainability through the integration of renewable energy, plug-and-play modularity, and elimination of secondary waste. Here, we discuss chemical and materials design strategies to impart electrochemically-controlled selectivity, reversibility, and enhance capacity for adsorption and membrane-based separations.

First, we discuss recent advances from our group on the design of redox-(co)polymers for imparting selectivity towards critical element recovery, materials recycling, and environmental remediation. Through synthetic control of redox-active moieties, we can superimpose non-covalent interactions onto electrodes that reach beyond double-layer effects, and achieve specificity towards target species. Areas of application include critical elements, transition metals, and persistent contaminants of concern, especially long-chain and short-chain PFAS. In particular, we showcase how co-operative design of interactions in redox-copolymer can enhance selectivity beyond homopolymer structure, and the synergistic role of solvation, electrostatics, and charge-transfer in selective ion binding. Next, we translate these approaches to innovate separation processes in chemical manufacturing, including the electrochemical recycling of homogeneous organometallic catalysts, and designing chiral interfaces for redox-mediated enantioselective interactions. We show that by “programming” the polymer structure, we can access precise control over binding and release towards structurally similar species.

Finally, we discuss considerations in device assembly and electrochemical engineering to coupled reaction and separation systems, to eventually lead towards process intensification. Our work highlights the tremendous versatility of electrochemical separations, and its potential for decarbonization and sustainability across major areas of chemical and biochemical manufacturing, resource recovery and recycling, environmental management, and water purification.