170
A. Arkatkar et al.
century (Schröder 2012) when the research was initiated for development in nearly
all aspects of MFC technology. In this reactor, the activity of oxidation and reduction
of electrons was separated in two chambers. In one chamber substrate was oxidized
by the microbes to generate electrons. These electrons were channelized to travel
in the second chamber; in this chamber either they will reduce a chemical or react
with air/oxygen. The chambers will be separated internally by means of a proton
permeable membrane (PEM) that allows the passage of protons toward the adjacent
chamber. The proton and electron combine with air/oxygen to form water (Logan
2008).
The different parts of MFC have their application in different fields. The anode
chamber, where the waste substrate is degraded mostly serves as a treatment facility.
The cathode chamber where the electrons and protons ultimately unite can be used as
a recovery system for different metals, (Liang et al. 2011; Rikame et al. 2018; Song
et al. 2016) as a biomass generation unit, (Gajda et al. 2015) as a hydrogen generation
unit (Ogawa et al. 2018), etc. Based on its application MFC is often conjoined with
other treatment facilities like septic tank, (Alzate-Gaviria et al. 2016) osmotic fuel
cell, (Qin and He 2017; Qin et al. 2015), etc.
2 Limitations of MFC
The MFC reactor has proven to treat domestic wastewater up to the level of an
activated sludge reactor (ASR) used in a wastewater treatment (WWT) plant (Asai
et al. 2017). The major setback for the commercialization of this technology is its
ability to produce limited power. The efficiency loss during scale-up process, higher
cost of PEM and the internal resistances in a reactor are thought to be the hindering factors behind the marketing of this technology (Logan et al. 2006; Mathuriya
et al. 2018). The various aspects taken into consideration for the reduction of these
internal resistances are (a) Designs of reactors; (b) Membranes; (c) Biofilms, and (d)
Electrodes.
The designs of reactors are majorly changing to reduce the internal resistance
in the MFC reactors. The work has been extensively done by researchers at Penn
State University (Logan et al. 2006) and Bristol Robotics Laboratory, West England
University (Ieropoulos et al. 2005). The researchers are also shifting from the lab scale
double chamber reactor to more feasible single chamber, air-cathode reactors because
its small size offers easy handling and mass experimentation with it at the laboratory
level. The different designs and structures are always casted as per the requirement of
the end application of this technology. The next aspect “membranes” are the costliest
part of the reactor. Membrane less reactors (Zhou et al. 2018; Zhu et al. 2011) and
ceramic membranes (Ghadge et al. 2014; Ieropoulos et al. 2013; Winfield et al. 2016)
are being studies for the replacement of costlier proton exchange membranes in the
reactors. The working force behind the technology is biofilm (Arkatkar et al. 2019).
The work on isolation of capable exoelectrogen is going on worldwide; the microbes
like Shewanella sp., Geobacter sp., etc. are studied in depth for understanding the
A. Arkatkar et al.
century (Schröder 2012) when the research was initiated for development in nearly
all aspects of MFC technology. In this reactor, the activity of oxidation and reduction
of electrons was separated in two chambers. In one chamber substrate was oxidized
by the microbes to generate electrons. These electrons were channelized to travel
in the second chamber; in this chamber either they will reduce a chemical or react
with air/oxygen. The chambers will be separated internally by means of a proton
permeable membrane (PEM) that allows the passage of protons toward the adjacent
chamber. The proton and electron combine with air/oxygen to form water (Logan
2008).
The different parts of MFC have their application in different fields. The anode
chamber, where the waste substrate is degraded mostly serves as a treatment facility.
The cathode chamber where the electrons and protons ultimately unite can be used as
a recovery system for different metals, (Liang et al. 2011; Rikame et al. 2018; Song
et al. 2016) as a biomass generation unit, (Gajda et al. 2015) as a hydrogen generation
unit (Ogawa et al. 2018), etc. Based on its application MFC is often conjoined with
other treatment facilities like septic tank, (Alzate-Gaviria et al. 2016) osmotic fuel
cell, (Qin and He 2017; Qin et al. 2015), etc.
2 Limitations of MFC
The MFC reactor has proven to treat domestic wastewater up to the level of an
activated sludge reactor (ASR) used in a wastewater treatment (WWT) plant (Asai
et al. 2017). The major setback for the commercialization of this technology is its
ability to produce limited power. The efficiency loss during scale-up process, higher
cost of PEM and the internal resistances in a reactor are thought to be the hindering factors behind the marketing of this technology (Logan et al. 2006; Mathuriya
et al. 2018). The various aspects taken into consideration for the reduction of these
internal resistances are (a) Designs of reactors; (b) Membranes; (c) Biofilms, and (d)
Electrodes.
The designs of reactors are majorly changing to reduce the internal resistance
in the MFC reactors. The work has been extensively done by researchers at Penn
State University (Logan et al. 2006) and Bristol Robotics Laboratory, West England
University (Ieropoulos et al. 2005). The researchers are also shifting from the lab scale
double chamber reactor to more feasible single chamber, air-cathode reactors because
its small size offers easy handling and mass experimentation with it at the laboratory
level. The different designs and structures are always casted as per the requirement of
the end application of this technology. The next aspect “membranes” are the costliest
part of the reactor. Membrane less reactors (Zhou et al. 2018; Zhu et al. 2011) and
ceramic membranes (Ghadge et al. 2014; Ieropoulos et al. 2013; Winfield et al. 2016)
are being studies for the replacement of costlier proton exchange membranes in the
reactors. The working force behind the technology is biofilm (Arkatkar et al. 2019).
The work on isolation of capable exoelectrogen is going on worldwide; the microbes
like Shewanella sp., Geobacter sp., etc. are studied in depth for understanding the