2.3.2 Cathode
Protons which are produced in the anodic chamber transfer into the cathodic
compartment passing the PEM, which completes the electrical current. The different
methods to increase the amount of oxygen in cathodic solutions had been offered
(Park et al. 2002; Rhoads et al. 2005). For instance, using an air pump and a proper
oxidant can successfully increase the amount of oxygen and consequently increase
the output power. Furthermore, using a catalyst such as Ptas an improving agent has
been investigated, but the mentioned materials are not cost-effective to use in MFCs,
so different biocathods have been offered to increase the amount of dissolved
oxygen of solution consequently (Park et al. 2002). Several important process
parameters such as microbial electron transfer, cell metabolism, internal and external
resistance, and cathode oxidation greatly affect generated electron transfer from
anode to cathode part and also MFC’s performance influenced by them (Rahimnejad
et al. 2014).
2.3.3 Proton Exchange Membrane
Proton exchange membrane (PEM) acts as a separator between the cathode and
anode box and is the most effective factor influencing MFCs’ performance (Chen
et al. 2008).
+Likewise, CEM same as PEM is one of the most extended used separators in
MFCs. It’s worth noting that PEMs prevent transferring substrates, minerals, and
oxygen from anodic compartment to cathodic compartment. Although they have
such a beneficial effect on MFCs’ operation, they cause high internal resistance (R in )
which is not known as a positive element. As a result, by removing PEMs which
results reduced R in , stacked MFCs, SC-MFCs, and upflow MFCs have been proposed by recent studies to reinforce their current generation (Chen et al. 2008). Here,
there are some of specific drawbacks related to PEMs as follows (Rozendal et al.
2008): (1) expensive nature; (2) cause lower cathode cell performance; (3) cause
lower efficiency and performance for MFCs; and (4) increase internal resistances.
2.4 MFC and Its Design
In terms of structure, there are different types of constructions for MFCs such as
SC-MFC, DC-MFC, and stacked ones, and each of the mentioned constructions
would be able to be used for specific purposes. In SC-MFCs the cathode is directly
exposed to air, and consequently there’s no need to provide a cathode compartment
for this type of MFCs. DC-MFCs consist of an anode and a cathode compartment
separated by a PEM which is well understood.
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M. Rahimnejad et al.
Protons which are produced in the anodic chamber transfer into the cathodic
compartment passing the PEM, which completes the electrical current. The different
methods to increase the amount of oxygen in cathodic solutions had been offered
(Park et al. 2002; Rhoads et al. 2005). For instance, using an air pump and a proper
oxidant can successfully increase the amount of oxygen and consequently increase
the output power. Furthermore, using a catalyst such as Ptas an improving agent has
been investigated, but the mentioned materials are not cost-effective to use in MFCs,
so different biocathods have been offered to increase the amount of dissolved
oxygen of solution consequently (Park et al. 2002). Several important process
parameters such as microbial electron transfer, cell metabolism, internal and external
resistance, and cathode oxidation greatly affect generated electron transfer from
anode to cathode part and also MFC’s performance influenced by them (Rahimnejad
et al. 2014).
2.3.3 Proton Exchange Membrane
Proton exchange membrane (PEM) acts as a separator between the cathode and
anode box and is the most effective factor influencing MFCs’ performance (Chen
et al. 2008).
+Likewise, CEM same as PEM is one of the most extended used separators in
MFCs. It’s worth noting that PEMs prevent transferring substrates, minerals, and
oxygen from anodic compartment to cathodic compartment. Although they have
such a beneficial effect on MFCs’ operation, they cause high internal resistance (R in )
which is not known as a positive element. As a result, by removing PEMs which
results reduced R in , stacked MFCs, SC-MFCs, and upflow MFCs have been proposed by recent studies to reinforce their current generation (Chen et al. 2008). Here,
there are some of specific drawbacks related to PEMs as follows (Rozendal et al.
2008): (1) expensive nature; (2) cause lower cathode cell performance; (3) cause
lower efficiency and performance for MFCs; and (4) increase internal resistances.
2.4 MFC and Its Design
In terms of structure, there are different types of constructions for MFCs such as
SC-MFC, DC-MFC, and stacked ones, and each of the mentioned constructions
would be able to be used for specific purposes. In SC-MFCs the cathode is directly
exposed to air, and consequently there’s no need to provide a cathode compartment
for this type of MFCs. DC-MFCs consist of an anode and a cathode compartment
separated by a PEM which is well understood.
222
M. Rahimnejad et al.