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19 Reaping of Bio-Energy from Waste Using Microbial Fuel Cell Technology

to the MFC in DET method. In MET, electrons are transferred by electrochemical

method, which is possibly metabolized by the microbes. The anaerobic bacteria

should act as a biocatalyst in MFC when acting as electron acceptors, by using

the way of facultative respiration species [14]. Recently, plenty of research reports

related to electrochemically active bacteria (EAB) are emerging. In MFC, several

microorganisms produce small amount of energy. With the presence of a mediator,

the electron transfer from the bacterial shell to anode shell is made easy. But, many

type of microorganisms can employ electron transfer directly from substrate to

electrode surface without mediator [15].

19.2.1.1

Electrode Materials in MFC

Electrode material is one of the unique performance in MFC for adhesion of

microorganism, electrochemical efficiency, and electron transfer. If the researchers

choose to use cost effective materials, the MFC will yield high electricity and

possible commercialization of MFC along with the environmental applications.

However, the electrode materials should have properties such as stability, durability,

electrical conductivity, surface area, porosity, cost effective, and ease of access for

effective operation of MFC.

Anode Material

Anode materials should have the following qualities such as (i) good

electrical conductivity, (ii) low resistance, (iii) chemical stability and anticorrosion,

(iv) high surface area, (v) robust biocompatibility, (vi) suitable mechanical strength,

and (vii) toughness. Most of the MFC studies are presented with carbon electrode

material. Carbon material-based anodes are in several varieties such as carbon cloth,

carbon paper, graphite rod, carbon felt, and graphite fiber brush [16]. The simplest

carbon anode used in MFC is graphite rod, in the interest of their excellent electrical

conductivity and low cost. Initially, materials made of carbon were used in hydrogen

fuel cell. Later, these materials were utilized in MFC for better performance while

decrease electrode distance and internal resistance. The performance of few non-

corrosive metals is assessed, and it does not produce more efficiency than carbon

materials.

Cathode Material The vital aspect of MFC is to control electricity generation. Elec-

trode support, catalyst, and air diffusion layer form the cathode in a typical MFC.

Generally, in MFC, the anode electrode materials can also be used as cathode elec-

trode material. However, the possible cathode material must have the properties of

good electric conductivity, high mechanical strength, and efficient catalytic nature

[17]. Commonly, MFC will be operated in Neutral state pH and ambient tempera-

ture conditions. At this phase, the oxygen reduction rate is very low. So, it limits the

performance of MFC. For vigorous reactions at cathode chamber in MFC, the car-

bonaceous materials must be revised with additional catalyst. In most of the MFC

operations, platinum is placed as a chief element because it plays a major role in

maintaining the survival of cathode catalyst which has high efficiency of oxygen

reduction rate. By using expensive cathode materials as catalyst in MFC, restricts

the commercialization of MFC technology. While using low quality water in MFC