Transient modeling of electrochemically assisted CO₂ capture and release

The present work aims to develop a model of a new electrochemical CO2 separation and release technology. We present a one-dimensional transient model of an electrochemical cell for point source CO2 capture and release, which mainly focuses on the simultaneous mass transport and complex chemical reactions associated with the separation process. For concreteness, we use an ionic liquid (IL) with 2 M thiolate anion (RS−) in 1 M disulfide (RSSR) as an electrolyte in the electrochemical cell to capture, transport and release CO2 under standard operating conditions. We computationally solved the model to analyze the time-dependent behavior of CO2 capture and electro-migration transport across the cell length. Given high nonlinearity of the system, we used a finite element method (FEM) to numerically solve the coupled mass transport equations. The model describes the concentration profiles by taking into account the individual transport of all participating species, charged as well as neutral. The model predicts performance characteristics of electrochemically assisted CO2 capture and release in terms of faradaic efficiency and cell current density as the cell dynamics evolves and approaches the steady state. The model provides an opportunity to better understand electrochemically assisted CO2 capture and release, and when coupled with experimental results will provide an early assessment of feasibility for large-scale application in realistic conditions.