The
graphite fiber fabric (GFF), modified using different methods,
was studied as an anode for enhanced bioelectrochemical methane production.
The electrical conductivity of the GFF was significantly improved
by loading the multiwall carbon nanotube (MWCNT) on the GFF surface
via electrophoretic deposition (EPD) or the sonication method. The
surface-modified GFF anodes were obtained by further processing to
form a scaffold layer of exfoliated graphite (EG) and the MWCNT mixture
using coal tar pitch or epoxy as the binder. In the batch bioelectrochemical
reactor, the lag time for the GFF control anode was about 15.5 days
in the methane production during the enrichment of electrochemically
active bacteria (EAB). Interestingly, the lag time for the modified
anode was increased more by the EPD treatment (20.8–23.3 days)
than by the sonication (17.1–18.4 days) and was increased more
by the epoxy binder (EB) (18.4–23.3 days) than by the coal
tar pitch binder (CB) (17.1–20.8 days). However, the accumulated
methane production of all modified GFF anodes increased by 12–70%
more than the production of the GFF control anode after the enrichment
of EAB. The highest values of the maximum methane production rate
(47.4 mL CH4/g COD·d) and the methane yield (322.0
mL CH4/g CODr) were obtained from the anode
modified using the CB after the EPD. On the basis of the electrochemical
analysis, the nickel loaded by the EPD has a catalytic activity for
the bioelectrochemical electron transfer, and the CB has a biocompatiblity
higher than that of the EB on the GFF surface. The GFF anode modified
with a scaffold layer of EG and MWCNT after the EPD treatment improves
bioelectrochemical methane production.