Fig. 5: Summary of the experimental concentrating cycles performed under 20, 40, 50, 100 and 150 mA cm−2 current densities and p1 = 0.5, 0.4, 0.3, 0.2 and 0.1 bar.
From: Low energy carbon capture via electrochemically induced pH swing with electrochemical rebalancing
TA is total alkalinity and DIC is dissolved inorganic carbon. Electrolytes comprised 10 mL of 0.11 M DSPZ in 1 M KCl (negolyte) and 35 mL of 0.1 M K4Fe(CN)6 and 0.04 M K3Fe(CN)6 in 1 M KCl (posolyte). The error bars refer to standard deviation. a CO2 molar deacidification, acidification, and cycle work vs. p1 for current densities indicated above the bars, in mA cm−2. In both (a) and (b) the horizontal axis is categorical, and each shadowed region refers to a single p1 value. b ΔDICflow,3→1 vs p1 for various current densities. c Deacidification work vs. p1 for various current densities. The “x” markers refer to measured data. The deacidification work of the cycles under pure N2 is used for p1 = 0.0 bar. d Acidification work vs. p1 for various current densities. The “x” markers refer to measured data. For each current density, the acidification work at p1 = 0.0 bar (“o” markers) is chosen to be the average value of the work obtained at other p1 values at the same current density. e CO2 molar deacidification, acidification and cycle work vs. current density for p1 = 0.1, 0.3 and 0.5 bar. The curves are fitted using a Tafel model. f Extrapolated CO2 molar deacidification, acidification and cycle work for p1 = 0.4 mbar. Extrapolation is performed using deacidification and acidification work at 0.0 bar p1 in (c) and (d), and divided by ΔDICTA–eq,3→1 at p1 = 0.4 mbar obtained from Fig. 4a and Supplementary Fig. 2b. The solid line refers to a Tafel model fit of CO2 molar cycle work vs. current density assuming TA3’i = 0.11 M (ΔDIC3→1 = 0.049 M) and the dashed line refers to the same fitting but assuming TA3′i = 0.0 M (ΔDIC3→1 = 0.097 M).
