T. Alan Hatton

T. Alan Hatton, Ph.D.
Massachusetts Institute of Technology
Department of Chemical Engineering

Abstract: Electrochemical Modulation of Sorbents for Selective CO₂ Separation Processes
The undisputed warming of the planet and increasing ocean acidification, with their strong implications for global climate and eco system changes, can be attributed to the increasing accumulation of anthropogenic CO₂ in both the atmosphere and in ocean waters.  Strategies to mitigate these effects cannot rely simply on accelerated use of renewable energy resources to replace fossil fuels, but must include the capture of CO₂ both at concentration from point sources, and at low concentrations from the ambient air or oceans, with subsequent subsurface sequestration or utilization. Traditional means for CO₂ capture and release generally rely on either chemical or physical interactions with sorbents with subsequent temperature or pressure changes to release the captured CO₂ and regenerate the sorbent. Isothermal operations that obviate or significantly reduce the heat integration requirements in these processes could potentially have significant advantages over the traditional methods in terms of complexity, energetics and cost of the overall capture operation. 

Electrochemically based technologies relying primarily on renewable energy resources for the capture and release of CO₂ under isothermal conditions may prove to be a reliable approach for addressing the environmental crises facing the world.  These approaches are suitable for both point-of-use gas emissions mitigation, and for removal of CO₂ from the atmosphere and ocean waters, where it has been accumulating for decades.  Examples include an indirect approach, in which an electrochemically released species (e.g., copper ions, protons) displaces the CO₂ bound to a chemical sorbent via competitive complexation; the CO₂ and the sorbents are regenerated when the species is re-captured in the cathode chamber of an electrochemical cell, leaving the sorbent free to be cycled back to the absorber.  An alternative approach exploits the complexation of an electroactive moiety directly with the CO₂ upon activation by electrochemical reduction, with subsequent release of the CO₂ when the agent is re-oxidized on reversal of the applied cell voltage.  The thermodynamic and electrochemical principles underlying these processes will be discussed, with examples from both the direct and indirect approaches. In general, these electrochemically based technologies hold promise for tackling the climate change challenges that we, and future generations, must face.

Biography:
T. Alan Hatton is the Ralph Landau Professor and Director of the David H. Koch School of Chemical Engineering Practice at the Massachusetts Institute of Technology.  He obtained his BSc and MSc degrees in Chemical Engineering at the University of Natal, Durban, South Africa, and worked at the Council for Scientific and Industrial Research in Pretoria for three years before attending the University of Wisconsin, Madison, to obtain his PhD.  He is currently Co-Director of the MIT Energy Initiative Low Carbon Energy Center for Carbon Capture, Utilization and Storage.  His research interests encompass self-assembly of surfactants and block copolymers, synthesis and functionalization of magnetic nanoparticles, and the exploitation of stimuli-responsive materials for chemical, environmental and pharmaceutical processing applications, with a particular current emphasis on electrochemically mediated operations for carbon dioxide capture.