(Zhang et al. 2016). Not only have oxidation of organic compounds been achieved,
but inorganic compounds have also been oxidized (Asaoka et al. 2012; Buatier de
Mongeot et al. 1998); although this does not enter into Fenton reactions, it shows
that it is a good option to use the combination of adsorption and oxidative processes
simultaneously.
5.5.2 Adsorption Assisted by an Oxidative Method
Unlike oxidative catalytic adsorption, the adsorption processes assisted by an oxidative method do not carry out the adsorption-oxidation process simultaneously;
rather, these are a process train, that is, it passes from one process to another, the
most common order being oxidation followed by adsorption. The reason for this
arrangement is due to the adsorption of degraded elements that present a lower risk
than the original contaminants before the oxidation process (Wang et al. 2010).
The degradation of contaminants by these assisted methods is usually greater than
that of oxidative catalytic adsorption since it is easier to control both processes
separately you can get efficiencies of up to 98% mineralization (Akrout et al. 2015),
although the operating time is significantly longer. Furthermore, it must be dealt with
that the adsorption process can be inhibited if it is not selective since part of the
reactants and byproducts of the reactions compete to occupy active sites, resulting in
a not very efficient removal (Kurniawan and Lo 2009). See Fig. 5.1.
5.6 Sustainable Energy from an Integrated Microbial Fuel
Cells-Electro-Fenton System
Since the electro-Fenton process is highly effective in the removal of refractory
effluents, the energy output from such systems is not always very much concentrated. A few reports on bioelectro-Fenton systems that can efficiently function as
effluent removal and the corresponding energy outputs are tabulated in the table: 3. It
can be seen that mostly the power output is of the order of 2 mWm
À2 . Even though
the energy output is low in bioelectroFenton system, being an integrated technique, it
has the advantage of the dual application. If we consider the design of microbial fuel
cells, the electrodes are mostly made of low-cost graphite/carbon-based materials
and wastewater is used as an electrolyte. This is a very cheaper prototype for the
production of electric power (Yu et al. 2018; Zhao and Kong 2018). But for the
practical implementation of bioelectroFenton in day-to-day life, the usage of power
from microbial fuel cells (MFCs) is very difficult since the energy production is not
constant and it will not be enough for operating devices. Alternatively, MFCs can be
used for powering some specific applications like MFC integrated sensors, metal ion
removal from wastewater through electrochemical reduction, dye degradation and
132
S. M. Sathianesan Vimala et al.
but inorganic compounds have also been oxidized (Asaoka et al. 2012; Buatier de
Mongeot et al. 1998); although this does not enter into Fenton reactions, it shows
that it is a good option to use the combination of adsorption and oxidative processes
simultaneously.
5.5.2 Adsorption Assisted by an Oxidative Method
Unlike oxidative catalytic adsorption, the adsorption processes assisted by an oxidative method do not carry out the adsorption-oxidation process simultaneously;
rather, these are a process train, that is, it passes from one process to another, the
most common order being oxidation followed by adsorption. The reason for this
arrangement is due to the adsorption of degraded elements that present a lower risk
than the original contaminants before the oxidation process (Wang et al. 2010).
The degradation of contaminants by these assisted methods is usually greater than
that of oxidative catalytic adsorption since it is easier to control both processes
separately you can get efficiencies of up to 98% mineralization (Akrout et al. 2015),
although the operating time is significantly longer. Furthermore, it must be dealt with
that the adsorption process can be inhibited if it is not selective since part of the
reactants and byproducts of the reactions compete to occupy active sites, resulting in
a not very efficient removal (Kurniawan and Lo 2009). See Fig. 5.1.
5.6 Sustainable Energy from an Integrated Microbial Fuel
Cells-Electro-Fenton System
Since the electro-Fenton process is highly effective in the removal of refractory
effluents, the energy output from such systems is not always very much concentrated. A few reports on bioelectro-Fenton systems that can efficiently function as
effluent removal and the corresponding energy outputs are tabulated in the table: 3. It
can be seen that mostly the power output is of the order of 2 mWm
À2 . Even though
the energy output is low in bioelectroFenton system, being an integrated technique, it
has the advantage of the dual application. If we consider the design of microbial fuel
cells, the electrodes are mostly made of low-cost graphite/carbon-based materials
and wastewater is used as an electrolyte. This is a very cheaper prototype for the
production of electric power (Yu et al. 2018; Zhao and Kong 2018). But for the
practical implementation of bioelectroFenton in day-to-day life, the usage of power
from microbial fuel cells (MFCs) is very difficult since the energy production is not
constant and it will not be enough for operating devices. Alternatively, MFCs can be
used for powering some specific applications like MFC integrated sensors, metal ion
removal from wastewater through electrochemical reduction, dye degradation and
132
S. M. Sathianesan Vimala et al.