Electricity Generation Performance of Plant Microbial FuelCells Separately Constructed by Four Wetland Plants

【Objective】Plant-microbial fuel cell (P-MFC) is a sustainable way for renewable energy production, but the electricity generation performance of P-MFC constructed by different plants and its relationship with external environmental factors and individual plant physiology remains to be explored.【Method】In this study, different P-MFCs were constructed by 4 wetland plants, including Brachiaria mutica, Cyperus malaccensis var. brevifolius, Pycreus polystachyus and Paspalum paspaloides. The performance of P-MFCs and their relationships with radial oxygen loss (ROL) and external environmental factors(pH, dissolved oxygen and temperature) were analyzed.【Result】The results showed that the 4 constructed P-MFCs had significantly different performance in voltage output, the average voltage output were 4.25±0.35, 1.57±0.35, 0.20±0.09 and 4.38±0.56 mW/m2 for B. mutica, C. malaccensis var. brevifolius, P. polystachyus and P. paspaloides, respectively. P-MFCs constructed with B. mutica and P. paspaloides produced more energy in general.This may be related to the lower rate of oxygen loss of B. mutica and the lower and stable pH in the cathode of P. paspaloidesMFC. The lower ROL helped to maintain a lower anode potential in B. mutica-MFC, while the lower cathode pH environment contributed to the higher cathode potential in P. paspaloides-MFC.【Conclusion】When constructing P-MFCs from wetland plants, the root features especially the root oxygen physiology should be taken into consideration.