3-Aminopropyltriethoxysilane Complexation with Iron Ion Modified Anode in Marine Sediment Microbial Fuel Cells with Enhanced Electrochemical Performance

Anode modification plays a key role in higher power output in marine sediment microbial fuel cells (MSMFCs). A low-molecular organosilicon compound (3-aminopropyltriethoxysilane) was grafted onto the surface of carbon felt using chemical method and a composite modified anode was prepared through organic ligands coordination Fe 3+ for better electro-chemical performance. Results show that the biofilm resistance of the composite modified anode (2707 δ) is 1.3 times greater than that of the unmodified anode (2100 Ω), and its biofilm capacitance also increases by 2.2 times, indicating that the composite modification promotes the growth and attachment of electroactive bacteria on the anode. Its specific capacitance (887.8 F m −2 ) is 3.7 times higher than that of unmodified anode, generating a maximum current density of 1.5 Am −2 . In their Tafel curves, the composite modified anodic exchange current density (5.25×10 −6 A cm −2 ) is 5.8 times bigger than that of unmodified anode, which suggests that the electrochemical activity of redox, anti-polarization ability and electron transfer kinetic activity are significantly enhanced. The marine sediment microbial fuel cell with the composite modified anode generates the higher power densities than the blank (203.8 mWm −2 versus 45.07 mWm −2 ), and its current also increases by 4.4 times. The free amino groups on the anode surface expands a creative idea that the modified anode ligates the natural Fe(III) ion in sea water in the MSMFCs for its higher power output.