Utilization of tubular bamboo biochar anode with different lengths in sediment microbial fuel cells

The amount of electricity generated depends on electron transfer, so the length of anode as electrode could be the determining factor for improving the performance of sediment microbial fuel cells (SMFC). In this study, tubular bamboo biochar with different lengths, namely SMFC-A3 (3 cm), SMFC-A6 (6 cm) and SMFC-A9 (9 cm), were used as anode material to reduce cost and carbon footprint in SMFC. We investigated the bioelectricity generation and anoxic sediment remediation from oyster farm of Tongyeong City, South Korea through SMFC system. Tubular bamboo biochar was characterized by elemental analysis (elemental composition), FESEM (morphology), TGA (weight loss) and XRD (crystalline framework). It was found that SMFC performance increased with increasing length of anode to improve the quality of anaerobic sediment (p < 0.05). SMFC-A6 generated the highest voltage of 50 mV among all cases. Polarization curves showed that SMFC-A6 achieved the highest maximum power density of 0.060 mW/m(2), with a fourfold and a onefold increase compared to SMFCA3 and SMFC-A9, respectively. In SMFC-A9, increase in redox potential and decrease in chemical oxygen demand (COD) was observed (-197 mV, 11 mg/L), compared to control case with sediment only (-240 mV, 25 mg/L). Removal efficiency of COD in SMFC-A9 and SMFC-A6 was 67 % and 61 % higher than that in SMFC-A3 (48 %). The result of the study could provide a simple strategy for coastal sediment remediation while generating bioelectricity.