Facilitating the electrochemical characterization and biofilm enrichment through anode modification in microbial fuel cells

Abstract

Poor anodic performance is a significant obstacle for scalable applications of air-cathode microbial fuel cells (MFCs), and it can be significantly improved with graphite anodic surface modifications. Morphological and electrochemical performance of modified anode with reduced graphene oxide rGO), polyaniline (PANI), carbon nanotubes (CNTs), each mixed with plant powder, showed improvement in electron transfer rate and anodic biocapacitance over unmodified anode in MFC. PANI-modified anode showed maximum power generation (149.7 mW/cm2) over other variations in MFCs. The highest COD percentage removal was obtained by the PAIN-modified anode (91.9%) followed by the CNTs-modified anode (86.7%) and the rGO-modified anode (82.4%). Electrochemical analyses revealed the enhancement in redox current generation with low charge transfer resistance with enrichment in electrogens in anodic biofilm using such anode modifiers, especially PANI, than unmodified anode in MFC. Biological and physiological analyses also support favoring electrogenic microbial activities and community structure towards the electroactive response and secretion of extracellular polymeric substances (EPS) for mediating electrons with modified anode conditions. Thus, the PANI-modified anode can be a promising and a sustainable anode candidate for MFC's long-term stability and scalable applications. Likewise, it could potentially be utilized as an innovative approach for developing a high-performance anode with extended operation for COD reduction in wastewater.