摘要
Increasing energy demands and environmental pollution concerns press for sustainable and environmentally friendly technologies.Soil microbial fuel cell(SMFC)technology has great potential for carbon-neutral bioenergy generation and self-powered electrochemical bioremediation.In this study,an in-depth assessment on the effect of several carbon-based cathode materials on the electrochemical performance of SMFCs is provided for the first time.An innovative carbon nanofibers electrode doped with Fe(CNFFe)is used as cathode material in membrane-less SMFCs,and the performance of the resulting device is compared with SMFCs implementing either Pt-doped carbon cloth(PtC),carbon cloth,or graphite felt(GF)as the cathode.Electrochemical analyses are integrated with microbial analyses to assess the impact on both electrogenesis and microbial composition of the anodic and cathodic biofilm.The results show that CNFFe and PtC generate very stable performances,with a peak power density(with respect to the cathode geometric area)of 25.5 and 30.4 mW m^(−2),respectively.The best electrochemical performance was obtained with GF,with a peak power density of 87.3 mW m^(−2).Taxonomic profiling of the microbial communities revealed differences between anodic and cathodic communities.The anodes were predominantly enriched with Geobacter and Pseudomonas species,while cathodic communities were dominated by hydrogen-producing and hydrogenotrophic bacteria,indicating H_(2)cycling as a possible electron transfer mechanism.The presence of nitrate-reducing bacteria,combined with the results of cyclic voltammograms,suggests microbial nitrate reduction occurred on GF cathodes.The results of this study can contribute to the development of effective SMFC design strategies for field implementation.
基金
This research was supported by the EU Horizon 2020 project GREENER(Grant Agreement No 826312).The authors wish to thank:Jakub Dziegielowski and Bongkyu Kim,from the University of Bath,for their suggestions and help on assembling and setting-up the SMFCs,Anna Salvian and Simone Krings,from the University of Surrey,for their assistance in DNA extraction.
