Abstract: Electrifying separation processes can be an important avenue for integrating renewable energy into traditionally energy processes, and promoting sustainability by minimizing chemical waste. Separation processes play a critical role in water purification, carbon dioxide mitigation, and chemical and biomolecular manufacturing, and can often be the most energy-intensive step in an industrial process. Electrochemical separations offer a sustainable alternative, by regulating kinetics and thermodynamics based primarily on electrical control.
Here, we will discuss the engineering of redox-interfaces for achieving molecular selectivity in electrosorption processes. First, the design of electrochemically-driven binding interactions is presented, by leveraging redox-active polymers as flexible platforms for controlling electronic properties. We present new electrochemical approaches for critical metal recovery and waste recycling, through structural control and tunability of charge-transfer interactions. Second, by asymmetric electrochemical design, electrosorbents and electrocatalysts can be configured to enable reactive separation within the same device, thus lowering overall energy costs and increasing current efficiencies. Finally, we discuss opportunities for the integration of redox-electrochemistry into electrochemical membrane processes such as redox-electrodialysis, for applications in desalination and even biomolecule recovery.
From a fundamental perspective, these concepts point towards an emerging direction in electrochemical interface design – by superimposing specific molecular interactions, we can reach beyond double-layer effects to achieve precision separations. In parallel, through judicious electrochemical engineering, we have demonstrated that reaction and separation steps can be coupled for electrochemical process intensification.
Bio: Xiao Su is an Assistant Professor in Chemical and Biomolecular Engineering at the University of Illinois, Urbana-Champaign. He obtained his Bachelor in Applied Sciences in Chemical Engineering from the University of Waterloo. He completed his PhD in Chemical Engineering from MIT.