Principle and efficiency of microbial fuel cell power generation

In most studies, the microbial fuel anode is attached to the air cathode.

The voltage is calculated by Ohm's law.

The surface area of the anode is its geometric area.

Open circuit measurement.

Short circuit measurement.

Flow field and fluid dynamics of direct microbial fuel cells

In the direct microbial fuel cell, the cathode chamber and the anode chamber constitute two different flow fields, which provide a place for microbial growth, reproduction and catalysis, while the microbial fuel cell also uses the battery electrode to replace the original natural electron acceptor of the microorganism, through the continuous transfer of electrons to generate electricity.

The electrons generated by the microbial oxidized fuel are transferred to the anode through the cell membrane associated group or through the REDOX mediator and then transferred to the cathode through the external circuit. In the cathode region electrons reduce electron acceptors (such as oxygen) and then combine with protons transferred through the proton exchange membrane to form water

Flow field: During the entire process of using organic matter to generate electricity in microbial fuel cells, biocatalytic particles or microorganisms constantly move in the flow field, accelerating the rapid renewal of reaction particles on the electrode surface and promoting the transfer of electrons on the anode surface.

Structure, design and assembly of direct microbial fuel cells

The structural design and assembly of direct microbial fuel cells is the key to their application. Microbial fuel cells are generally divided into two categories: one cell type and two cell type. The two-compartment microbial fuel cell is widely used, which has an anode chamber and a cathode chamber.

Separator materials: At present, the separator materials used by microbial fuel cells are mainly: proton membrane, salt bridge, glass beads, glass fiber and carbon paper, etc., and proton membrane is widely used. At present, the commonly used carbon paper is Taiwan carbon energy brand.

In terms of diaphragm materials, the structure of two-compartment microbial fuel cells is complex, and the mass transfer resistance of one-compartment microbial fuel cells is less than that of two-compartment microbial fuel cells because of the omission of cathode chamber. Attempts have been made to hot-press the cathode and the proton membrane together to reduce the resistance of proton transfer in the cathode chamber. The surface of carbon cloth electrode is coated or sprayed with proton exchange resin to make cathode - proton film type and anode - proton film - cathode type microbial fuel cell electrode.

Research battery materials should be considered

The problems of biological reaction system, as mentioned above, mainly involve the electrical production performance of microorganisms, media engineering, and the electron transfer path in the process of microbial degradation of organic and inorganic pollutants, which affect the performance of microbial system;

The relationship between the structure of the microbial fuel cell itself and the pollutant treatment capacity and the material properties of the microbial fuel cell.

Cathode materials: The commonly used cathode materials for microbial fuel cells are carbon paper, carbon cloth and carbon yarn, graphite, graphite plate and graphite rod. Recent research and development of new materials are often based on the above mentioned materials to improve.

Anode materials: Unlike the typical anode reactions used in chemical fuel cells, microbial fuel cells have a more complex reaction on the anode due to the involvement of microorganisms and chemicals. Therefore, the anode material must also have good biological adaptability, excellent electrical conductivity, corrosion resistance, high specific surface area and high porosity.

Diaphragm material: In laboratory scale microbial fuel cell experiments, well-known membranes, such as proton exchange membrane (Nation-liT), cation exchange membrane (CEM-1-UltrexTM CMI7000), anion exchange membrane (Fumasep FAD), bipolar membrane (Fumasep FBM), etc. But in practice, some membranes without electrical properties, such as microfiltration membranes, have also been introduced as an option for microbial fuel cell research.

Model calculation of microbial fuel cell

Based on the Monod equation, the anode chamber can be regarded as a microbial reactor. Using the theory of microbial electrochemistry, the relationships among parameters of matrix degradation, microbial growth and power generation capacity can be expressed by mathematical models.

In the microbial fuel cell process system, the main problems existing in the application process control are as follows:

The reaction process of microbial fuel cell is complex. The whole processing process is composed of several operating units, in the same unit and a number of completely different reactions, including physicochemical and electrobiological reactions.

Many of the parameters that affect the characteristics of the system are difficult to control (such as instantaneous flow, organic input changes, toxic input and inlet temperature, etc.).