Poorly conductive biochar boosting extracellular electron transfer for efficient volatile fatty acids oxidation via redox-mediated mechanism.
Sci Total Environ
; 809: 151113, 2022 Feb 25.
Article
em En
| MEDLINE
| ID: mdl-34688743
ABSTRACT
This study explored the performances, and associated mechanisms of biochar promoting volatile fatty acids (VFA) oxidation via extracellular electron transfer (EET) pathway. It was found that in a bioelectrochemical system, adding biochar suspension remarkably enhanced electricity generation whatever acetate or propionate used as an electron donor. The maximum current density in biochar-assisted groups reached 1.6-2.2 A/m2, which were 69.2-220.0% higher than that of control groups. The lower electrical resistance of anode in biochar-assisted groups was potentially attributed to the formed biofilm dominated by electro-active Geobacteraceae, and the electron donor type depending on dominant genus. In specific, with biochar assistance, Desulfuromonas enriched from 1.1% to 25.0% when acetate as an electron donor, and the relative abundance of Geobacter increased from 4.6% to 31.7% as dominant genus in propionate-added group. Electrochemical analysis uncovered that biochar hardly elevated sludge electrical conductivity, while the excellent redox-based electron exchange transfer capacity likely made biochar as a transient electron acceptor, which was more accessible than anode to support the metabolism of electroactive bacteria in the initial stage. Meanwhile, the porous surface area of biochar particle likely provided a "bridge" between suspended sludge and anode, to support a more directional evolution of electroactive bacteria on anode. This dual-function of biochar achieved a sustainable VFA oxidation via EET-based pathway.
Palavras-chave
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Elétrons
/
Ácidos Graxos Voláteis
Idioma:
En
Revista:
Sci Total Environ
Ano de publicação:
2022
Tipo de documento:
Article