fig3

Figure 3. (A) A schematic of a MES reactor showing the replacement of a conventional submerged flat cathode with an electrically conductive, catalytic, and porous hollow-fiber (CCPHF) cathode. (B) Nyquist plots of Ni-PHF and Ni-PHF/CNT in sterile blank medium. The inset is the equivalent circuit for EIS fitting. (C) Comparison of CO₂ adsorption capability of Ni-PHF and Ni-PHF/CNT cathodes. SEM images taken at the end of batch 8 for the cathodic biofilms developed on (D) Ni-CCPHF cathodes of an experimental reactor and (E) Ni-CCPHF that was used only as a gas-transfer membrane for CO₂ delivery (left) and served only as a cathode (right). (F) Electron transfer, measured acetate production, and current consumption of the Ni-PHF cathode (left) and the Ni-PHF/CNT cathode (middle), both with direct CO₂ delivery through the pores of the hollow fibers. MES performance of the Ni PHF/CNT cathode (right) with CO₂ bubbled into the medium. This figure is quoted with permission from Alqahtani et al.^[22] and Bian et al.^[101].