Carbonate Regeneration Using a Membrane Electrochemical Cell for Efficient CO2 Capture

Abstract

The use of atmospheric CO2 as a chemical feedstock is a promising way to decarbonize the chemical and transportation sectors, which currently rely heavily on fossil fuels. This transition demands new technologies to reduce the energy required to capture and separate CO2. Here, we develop and demonstrate an alternative method of carbonate solution regeneration using an anion exchange membrane electrochemical cell. This process simultaneously regenerates the CO2 capture solution on the feed side, while enriching a stream of H2 with CO2 on the permeate side of the cell. Preliminary results show a CO2 transport faradaic efficiency of 50% (100% CO32- transport) when supplying a pure K2CO3 solution at current densities up to 60 mA·cm-2. A small cathode gap benefited cell operation by preventing membrane transport of OH-, although with an increased ohmic resistance. This represents a step forward in the application of electrochemistry to drive processes that are critical to CO2 valorization.