The effects of carbon electrode surface properties on bacteria attachment and start up time of microbial fuel cells

Surface roughness, porosity and contact angles of different carbon paper materials (TORAYpaper with PTFE from 0% to 60% of and SGL paper with 0% and 20% of PTFE) suitable aselectrodes in microbial fuel cells were investigated. The changes of contact angle betweendry and clean anode surfaces and the ones after exposure to wastewater were measuredusing different liquids (pure water and sodium acetate solutions). The results showed thatbacterial attachment to the carbon papers caused a significant decrease in the contactangle, shifting the surface property from highly hydrophobic to slightly hydrophobic oreven hydrophilic. The quantity of biofilm attached on the anode surface decreased withthe increase in PTFE content. Positive correlation between dry biomass content and theamount of pores at the small scale (5–10 lm) was observed. The start up time of MFCswas shortened by using the carbon anodes without PTFE or with low PTFE content(the carbon anodes with high PTFE contents had longer start up time. After several cyclesof MFC operation, the performances became similar (20–30 mV of differences) regardlessof the carbon anode used.