Wetland plant microbial fuel cells for remediation of hexavalent chromium contaminated soils and electricity production

• Published in: Journal of hazardous materials Vol. 365; pp. 137 - 145
• Main Authors: Guan, Chung-Yu, Tseng, Yi-Ho, Tsang, Daniel C.W., Hu, Anyi, Yu, Chang-Ping
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 05.03.2019
• Subjects: Chinese pennisetum; Cr(VI); Electricity production; Graphite carbon felt; Plant microbial fuel cell; Cr(VI); Graphite carbon felt; Electricity production; Plant microbial fuel cell; Chinese pennisetum
• ISSN: 0304-3894; 1873-3336
• DOI: 10.1016/j.jhazmat.2018.10.086

[Display omitted] •Wetland PMFCs efficiently remove soil Cr(VI) and generate electricity.•Bioelectrochemical process is the major mechanism for Cr(VI) removals.•PMFC systems could achieve 99% Cr(VI) and 27.4% total Cr removals in soils.•Graphite carbon felt electrodes could achieve 264% output voltage compared with regular ones in the best performing PMFCs. The plant microbial fuel cell (PMFC) is a novel technology which integrates plants, microbes, and electrochemical elements together to create renewable energy. However, information regarding using the PMFC system to remediate metal-contaminated soils is still limited. In this study, we evaluate the potential of PMFC systems to remediate soils polluted by Cr(VI). We compare different plants and different electrode materials with regard to their electricity generation and Cr(VI) removals under different soil Cr(VI) concentrations. In PMFC systems, the soil pH was transformed from slightly acidic to neutral, and the electrical conductivity was reduced during operation. The removal efficiency of Cr(VI) in soils could reach 99%, and the total Cr of soils could also be reduced. The closed circuit voltage of PMFC systems of Chinese pennisetum using the graphite carbon felt as the electrodes could reach the daily average value of 469.21 mV. PMFC systems have successfully demonstrated the ability to remove Cr(VI) from soils collected from actual metal-contaminated sites. Our results suggest that using PMFCs to remediate contaminated soils is promising, and the effects of decontamination are mostly contributed by bioelectrochemical processes and plant uptake.