The living energy recovery system utilises the bacteria from wastewater and brings forth a one-two punch for environmental sustainability efforts. The natural population of bacteria facilitates decontamination of groundwater as it breaks down harmful chemical compounds. Now, new research has proposed a practical way through which this process can also harness renewable energy.
The researchers have made a massive advancement in the Fuel Cell Market as they developed a technology that uses natural bacteria to acquire electrons from organic matter present in the wastewater. This results in the generation of electrical currents.
The study's primary focus was on the bacteria genus Shewanella – a widely studied commodity because of its energy-generating characteristics. They are unique and can grow and thrive in various environments such as seawater, soil, and wastewater. Further, the oxygen levels present in the surroundings do not affect the bacteria.
Shewanella can naturally break down organic waste matter into small molecules, wherein electrons come out as the by-product of the metabolic process. When bacteria grow as films on electrodes, a few of the electrons can be collected, resulting in the formation of a microbial fuel cell that generates electricity. However, it was noticed in previous processes that microbial cells powered through Shewanella oneidensis did not trap enough currents from bacteria to make it applicable for industrial use. This is because only a few electrons could escape the bacteria's membranes and penetrate the electrodes quickly enough to create adequate electrical currents and power.
To counter this problem, the team added silver nanoparticles to electrodes comprising a type of graphene oxide. The nanoparticles release silver ions. The bacteria reduce them to silver nanoparticles with the help of electrons generated from metabolic processes and then merge them into their cells. Once silver particles get inside the bacteria, they act as microscopic transmission wires and trap many electrons. Silver nanoparticles inside the bacteria behave like a unique express lane specially made for electrons enabling one to extract numerous electrons quickly.
As the electron transport efficiency improves, the silver-infused Shewanella film also produces more than 80 percent metabolic electrons. Hence, a power of 0.66 milliwatts per square centimeter is generated - an achievement that is double the current best microbial fuel cells. By demonstrating a way to increase currents and enhance efficiency, the present study may even open a new window of opportunities for sufficient power output.