Removal of petroleum hydrocarbon-contaminated soil using a solid-phase microbial fuel cell with a 3D corn stem carbon electrode modified with carbon nanotubes.

Solid-phase microbial fuel cell (SMFC) can accelerate the removal of organic pollutants through the electrons transfer between microorganisms and anodes in the process of generating electricity. Thus, the characteristics of the anode material will affect the performance of SMFCs. In this study, corn stem (CS) is first calcined into a 3D macroporous electrode, and then modified with carbon nanotubes (CNTs) through electrochemical deposition method. Scanning electron microscope analysis showed the CS/CNT anode could increase the contact area on the surface. Furthermore, electrochemical impedance spectroscopy and cyclic voltammetry analysis indicated the electrochemical double-layer capacitance of the CS/CNT anode increased while its internal resistance decreased significantly. These characteristics are crucial for increasing bacterial adhesion capability and electron transfer rate. The maximum output voltage of the SMFC with CS/CNT anode was 158.42 mV, and the removal rate of petroleum hydrocarbon (PH) reached 42.17%, 2.72 times that of unmodified CS. In conclusion, CNT-modified CS is conducive to improve electron transfer rate and microbial attachment, enhancing the removal efficiency of PH in soil.