Soil Microbial Fuel Cell with Hydrophilic Treated Buckypaper Anodes

Abstract

Fossil fuels, the primary source of energy supply in modern society, are both unsustainable and damaging to the environment. The most cost-effective way to reduce the use of fossil fuels is to switch to renewable energy sources. Soil microbial fuel cells (SMFC) are a green energy production method because they use electron-generating bacteria in the soil to obtain electrical energy from organic matter. One way to improve the output of SMFCs is to increase the specific surface area of the anodes. The larger specific surface area allows more electrons to be received from the bacteria. In this study, bucky paper (BP) was utilized as the anode of SMFC. BP is a freestanding film fabricated from multi-walled carbon nanotubes (CNT) by vacuum filtration method. CNT has a high specific surface area and electrical conductivity. BP is also considered to be mechanically stable in soil due to its CNT network structure. However, the surface of the BP is hydrophobic. In SMFCs, the hydrophobic surface of the anode is a fatal disadvantage in terms of the affinity of microorganisms. Thus, heat treatment and UV ozone treatment were employed to make the surface of BP hydrophilic, and their output in SMFCs was investigated. As a result, SMFCs using UV-ozone-treated BPs as anodes produced the highest power density of 28.8 μW/cm². Also, unlike thermal treatment, UV ozone treatment did not damage the CNT structure. Hence, in this experiment, the output power of the SMFC was stable for at least 140 hours.