Promoting electricity generated from sediment-based microbial fuel cells and remediation of copper-containing sediments using plant radial oxygen loss and root exudates

Abstract

This study uses root exudates and radial oxygen loss (ROL) produced by plants to increase the amount of power produced by sediment microbial fuel cells (SMFCs) and improve copper removal. Among the three plants tested, which are commonly found in wetlands, Ipomoea aquatica produces the highest yield of root exudates and ROL, with respective values of 8.54 mg/(g‧d) and 2.1 μmol/(g‧h) at 50-mg/L Cu inhibition. The maximum power density of an SMFC with 450 mg/kg of copper-containing sediment and Ipomoea aquatica planted at the anode is 58.4 mW/m3, which is three times greater than that of an SMFC with Ipomoea aquatica planted at the cathode. This demonstrates that plant root exudates provide anodic microorganisms with easily decomposed organic matter, which increases the amount of power. The presence of a bioelectrochemical process is demonstrated by the presence of Cu(II) reduction deposits on the cathode surface. According to the findings, planting Ipomoea aquatica at the anode produces more electricity and removes slightly less copper than planting it at the cathode. It is concluded that planting Ipomoea aquatica at the anode is more effective than planting it at the cathode.