Three-dimensional amino modification carbon nanotubes/graphene composite aerogel anode enhanced Geobacter enrichment and performance in microbial electrochemical systems

Regulating anode structure and component are necessary to the operation of the microbial electrochemical system (MES). In this work, graphene-based amino modification carbon nanotubes composite aerogel is prepared through simple hydrothermal reduction method. It is proved that the three-dimensional (3D) structure can provide a plenty of sites for microorganisms growth. The carbon nanotubes inserted in the graphene sheets can provide more paths for electron conduction in the anode and can enhance the electron transfer process. The introduction of amino groups promote the population of Geobacter in anode biofilm and further enhance the performance of the system. The maximum power density of the MES equipped with the composite anode can reach 944.3 W m−3, higher than previously reported high-output MESs with 3D graphene-based anodes. Meanwhile, the maximum current density of the system (2637.8 A m−3) increases 39.9% compared to the control anode system (1586.3 A m−3). The graphene-based amino modification carbon nanotubes composite anode in this study shows great potential for enhancing the performance of MES.