Evaluation of the Effect of Graphite Powder in Decreasing the Internal Resistance for Microbial Fuel Cell Using Soil

Abstract

The graphite powder was added to a microbial fuel cell (MFC) that uses soil to decrease the internal resistance and increase the electric power and electric charge (ampere hour: Ah). The effect of adding the graphite powder to soil MFC is evaluated by experiment and simulation using mathematical models. In this experiment, the total weight of the reddish granular soil and the graphite powder was 1000 g, and ratios of the graphite were set to five values between 0% and 20% by weight. The grain size of the soil was between 3 and 8 mm. The diameter of electrode was 9 cm. The initial chemical oxygen demand (COD) of synthetic wastewater was 1400 mg/L. As a result, the amount of Ah was maximized when 10% of the graphite was mixed. When the amount of the graphite increased, the internal resistance decreased; however, consumption of COD decreased and the microbial reaction decreased. This might be because the graphite covers the surface of the soil, and it disturbs the adsorption of the soil and decreases the biofilms. Therefore, a suitable proportion of the graphite exists, and it was approximately 10% in this experiment.

Evaluation of Methods for Measuring Internal Resistances of Discharging Microbial Fuel Cells

“…However, the one-resistance method has been used instead of the multi-resistance method in the OC and CC modes by our group. The results showed appropriate values of the internal resistances [5].…”

“…Panto et al [3] and Pinto et al [4] remarked that the low power density and restricted output voltage of MFCs limit their industrial applications. Additionally, the high internal resistance of MFCs is a concern [5]. Therefore, these internal resistances of MFCs should be precisely evaluated to enable their analysis and reduction.…”

Integrating microbial fuel cell with sedum green roof for stormwater retention and renewable energy generation

“…Garden soil mixed with graphite powder (Fasco Epoxies, cat# 0819794021036) with a 30:1 ratio was filled in the planter with a 4 cm thickness to cover the anode felt (Figure 8D). Adding graphite powder to a soil MFC could reduce its internal resistance and increase electric power (18). Sedum plants and soil media were added to the planter with a total soil thickness of 14 cm (Figure 8E).…”