Home > Articles > Published articles > Microbial electrosynthesis of acetate from CO2 in three-chamber cells with gas diffusion biocathode under moderate saline conditions |
Date: | 2023 |
Abstract: | The industrial adoption of microbial electrosynthesis (MES) is hindered by high overpotentials deriving from low electrolyte conductivity and inefficient cell designs. In this study, a mixed microbial consortium originating from an anaerobic digester operated under saline conditions (∼13 g L−1 NaCl) was adapted for acetate production from bicarbonate in galvanostatic (0. 25 mA cm−2) H-type cells at 5, 10, 15, or 20 g L−1 NaCl concentration. The acetogenic communities were successfully enriched only at 5 and 10 g L−1 NaCl, revealing an inhibitory threshold of about 6 g L−1 Na+. The enriched planktonic communities were then used as inoculum for 3D printed, three-chamber cells equipped with a gas diffusion biocathode. The cells were fed with CO2 gas and operated galvanostatically (0. 25 or 1. 00 mA cm−2). The highest production rate of 55. 4 g m−2 d−1 (0. 89 g L−1 d−1), with 82. 4% Coulombic efficiency, was obtained at 5 g L−1 NaCl concentration and 1 mA cm−2 applied current, achieving an average acetate production of 44. 7 kg MWh−1. Scanning electron microscopy and 16S rRNA sequencing analysis confirmed the formation of a cathodic biofilm dominated by Acetobacterium sp. Finally, three 3D printed cells were hydraulically connected in series to simulate an MES stack, achieving three-fold production rates than with the single cell at 0. 25 mA cm−2. This confirms that three-chamber MES cells are an efficient and scalable technology for CO2 bio-electro recycling to acetate and that moderate saline conditions (5 g L−1 NaCl) can help reduce their power demand while preserving the activity of acetogens. |
Grants: | Agència de Gestió d'Ajuts Universitaris i de Recerca 2021/SGR-01352 European Commission 101029266 European Commission 101000441 |
Rights: | Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial, la distribució, i la comunicació pública de l'obra, sempre que no sigui amb finalitats comercials, i sempre que es reconegui l'autoria de l'obra original. No es permet la creació d'obres derivades. |
Language: | Anglès |
Document: | Article ; recerca ; Versió publicada |
Subject: | Acetobacterium ; Bioelectrochemical system ; Conductivity ; Electrochemical cell design ; Gas diffusion electrode |
Published in: | Environmental science and ecotechnology, Vol. 16 (October 2023) , art. 100261, ISSN 26664984 |
10 p, 4.1 MB |
Supplementary data 7 p, 548.3 KB |