Effect of Amino Acid Addition in Marine Sediment on Electrochemical Performance in Microbial Fuel Cells

As exogenous substances, L-methionine, L-threonine and L-lysine were added into the marine sediment to construct marine sediments microbial fuel cells (MSMFCs) and the effects on the anodic electrochemical activity were following investigated. The results show that the addition of the amino acid increases anodic electrochemical activity, and the anode in L-methionine modified sediment presents better performance than others. The specific capacitance of anode in L-methionine modified sediment (192.00 F cm(-2)) is 4.0 times bigger than that of anode in unmodified sediment, generating a maximum current density of 2.560x10(-4) A cm(-2). In their Tafel curves, the anodic exchange current density in the L-methionine modified sediment (2.14x10(-6) A cm(-2)) is 93.04 times higher than that of unmodified anode, which suggests that the electrochemical activity of redox, anti-polarization ability and electron transfer kinetic activity are improved significantly. The MSMFC with L-methionine modified sediment generates the higher power densities than the blank (143.2 mW m(-2) versus 59.2 mW m(-2)), and its current also increases by 2.8 times. This demonstrates that L-methionine provides a practical advantage on the anodic electrochemical and battery performance. Therefore, amino acids are good tools to evaluate its power generation of the MSMFCs.