Effects of biofilm growth on the electrochemical behavior of graphite anodemodified with polyaniline in microbial fuel cells

The effect of bacterial colonies on graphite sheet (Gr) and electrochemically modified graphite sheetwith polyaniline (PAN-Gr) was carefully investigated in view of pseducapacitive and stable current ofbioanode at a microbial fuel cell (MFC). The electrochemical behavior of bionodes at MFC wasstudied by chronoamperometry, chronopotentiometry, cyclic voltammetry and electrochemicalimpedance spectroscopy (EIS). The OCP determination of bioanodes showed that the graphite modifiedwith polyaniline starts from a more positive potential and reaches its minimum potential in a shortertime, while the potential of the graphite decreases more slowly, indicating a better growth of thebiofilm on the PAN-Gr bionanode. The cyclic voltammetry investigation of PAN-Gr bioanode duringvarious days proved that with the growth of bacteria and the formation of biofilm during time, the areaunder curve of the voltammogram is increased, which can be attributed to the increasing of capacitanceof the bionanode originated from pseducapacitive behavior of polyaniline. EIS studies showed that thegrowth of bacteria on the surface of the PAN- Gr bioanode not only significantly decreases chargetransfer resistance, but also increases capacitance of the bioanode compared to unmodified graphiteelectrode.

کلیدواژه ها:

biofilm ، graphite anode ، microbial fuel cell ، Chronoamperometry ، Supercapacitor ، Polyaniline