Effect Of Graphene Modified Electrode On Electricity Generation In Microbial Fuel Cells

Microbial fuel cell (MFC) as a clean production, is a kind of reactor which can convertchemical energy to electricity through the catalytic reaction of anaerobic microorganisms, itcan treat organic wastewater while producing electricity. Currently, many simple organiccompounds have been employed as MFC fuels such as glucose, acetic acid, ethanol, etc.These cells can run well and effectively degrade organics.Acetaminophen (APAP) is a typical PPCPs pollutants, when ingested, only a small partof them metabolized in human body, most of them discharged into water bodies viaprototype. In this paper, the electricity generation of MFCs was employed as the mainresearch object, with graphene as main material to modify anode and cathode of MFCs, tostudy the electricity generation and influencing factors of modified MFCs. Meanwhile,acetaminophen was adopted as anode target pollutants for degradation and electricityproduction research, access to the following main conclusions:1. Graphene modified cathode(1) A two-chamber fuel cell was constructed with copper as cathode, stainless steel wiremesh as the anode, using graphene dispersion modified cathode by different dispersants. Itfound that electricity production of CMC-graphene-MFC system was superior toPEG4000-graphene-MFC system, and their maximum power density (PA) were4.33timesand1.56times to unmodified MFC respectively.(2) To study the effect of copper cathode area and APAP concentration on electricitygeneration, results showed that the best PAvalue was obtained when cathode area was2×3cm2, and the output voltage can reach higher when APAP concentration was400mg/L.(3) Carbon cloth cathode was employed to build dual chamber MFC based on coppercathode/MFC. SEM results showed that modified cathode surface accumulated morereduction products than unmodified cathode. CV curve showed that the peak current increasedafter cathode modified by graphene. These results further demonstrated the electricitygeneration of modified cathode cells were superior to unmodified cells.2. Graphene modified anodeCopper sheet, carbon cloth and stainless steel wire mesh were employed as anoderespectively with carbon cloth as cathode to build dual-chamber MFC. Results showed thatgraphene modified anode could improve PAvalues. PAvalues of modified copper/MFC,carbon cloth/MFC, stainless steel wire mesh/MFC system were39.63μW,9.67μW,101.20μW, which were17times,1.20times and1.51times to the unmodified cells respectively. 3. APAP kinetic analysis(1) Three kinetic equations were adopted to fit the degradation process of APAP ingraphene modified copper cathode/MFC and carbon cloth cathode/MFC system. Resultsshowed that the degradation of APAP in both systems fitted to zero order kinetic equation, thisshows that the degradation of APAP were independent to APAP concentration, which mayrelate to surface properties of graphene modified cathode.(2) Using three kinetic equations to fit the degradation process of APAP in graphenemodified copper anode/MFC, carbon cloth anode/MFC and stainless steel wire mesh anode/MFC system. Results found that the degradation of APAP in copper/MFC and carboncloth/MFC system fitted to zero order kinetic equation, while the degradation of APAP instainless steel mesh/MFC systems met first kinetic equation. This shows that the degradationof APAP were independent to APAP concentration in copper/MFC and carbon cloth/MFCsystem, which may relate to their surface properties of graphene modified anode, and thedegradation of APAP was related to APAP concentration in stainless steel wire mesh/MFCsystem.