The present study
reports about the fabrication of a three-dimensional
(3D) macroporous steel-based scaffold as an anode to promote specifically
bacterial attachment and extracellular electron transfer to achieve
power density as high as 1184 mW m–2, which is far
greater than that of commonly used 3D anode materials. The unique
3D open macroporous configuration of the anode and the microstructure
generated by the composite coating provide voids for the 3D bacterial
colonization of electroactive biofilms. This is attributed to the
sizeable interfacial area per unit volume provided by the 3D corrugated
electrode that enhanced the electrochemical reaction rate compared
to that of the flat electrode, which favors the enhanced mass transfer
and substrate diffusion at the electrode/electrolyte interface and
thereby increases the charge transfer by reducing the electrode overpotential
or interfacial resistance. In addition, bacterial infiltration into
the interior of the anode renders large reaction sites for substrate
oxidation without the concern of clogging and biofouling and thereby
improves direct electron transfer. A very low overpotential (−27
mV) with a very low internal resistance (7.104 Ω cm2) is achieved with the fabricated microbial fuel cell (MFC) that
has a modified 3D corrugated electrode. Thus, easier and faster charge
transfer at the electrode–electrolyte interface is confirmed.
The study presents a revolutionary practical approach in the development
of highly efficient anode materials that can ensure easy scale-up
for MFC applications.
The present paper reports for the first time the development and application of novel Zn wetted CeO 2 (Zn/ CeO 2 ) composite galvanic zinc coating to combat microbial induced corrosion (MIC). Zinc metal−metal interaction causes the effective incorporation of composite into the galvanic coating and accordingly increases the active sites for antibiofouling activity. The developed coatings are explored for their anticorrosion/antibiofouling characteristics toward MIC induced by cultured seawater consortia. Enhanced antibiofouling activity of the composite galvanic coating is achieved due to the tuned content of 28 wt % Zn and 34 wt % of Ce. High charge transfer resistance as high as 4.0 × 10 14 Ω cm 2 and low double layer capacitance as low as 3.99 × 10 −8 F are achieved by tuning the structure and composition of the coating. The synergistic effect of Zn and Ce ensures the stability and corrosion resistance of the coatings in a corrosive bacterial environment. Evident decreases in the bacterial attachment and biofilm formation are illustrated using antibiofouling assay. The antibiofouling activity is attributed to the effective reduction of Ce 4+ to Ce 3+ and the shuttling characteristics of oxidation state of CeO 2 . This impairs the cellular respiration and results in bacterial death. Thus, it can be used as an effective coating to protect the steel based equipment in corrosive marine environments to combat marine microorganisms and their interactions. The present study also paves the scope for exploration of similar effective protective systems.
The
present paper reports for the first time the construction of
a sugar cane bagasse-mediated double-chambered microbial fuel cell
(MFC), consisting of a novel bioanode of an iron/titanium Ni–P
composite. This anode could facilitate uninterrupted extracellular
electron transfer (EET) from bacteria (mixed culture). The Ni–P
composite anode had a significant corrosion resistance and enhanced
electrocatalytic activity. The corrosion rate was reduced to 0.187
mmpy, which was 3 times less than that of the noncomposite anode.
A steady decrease in internal resistance from 3.84 × 103 Ω to 2.94 × 102 Ω was achieved with
the incorporation of the iron/titanium-based composite on the anode
surface. The presence of Fe (III) ion centers in the composite surface
favored electroactive biofilm formation and enhanced the capacitive
nature of the anode, thereby accelerating EET. The constructed MFC
showed an internal resistance as low as 1.12 × 10–2 Ω in comparison with the control MFC. This led to a very high
power density of ∼2.1 W/m2, which was 20% higher
than that of the control MFC, while a stacked MFC obtained a maximum
open-circuit potential of 3.2 V with power density and current density
outputs of 6.3 W/m2 and 2.7 mA/m2, respectively.
Even though an extensive amount of literature is available in this
field, this report is the first of its kind because it includes such
a simple reproducible system that can be extended to other similar
systems.
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