Enhancement of electrode properties using carbon dots functionalized magnetite nanoparticles for azo dye decolorization in microbial fuel cell

Technology integration of nanomaterials with microbial fuel cell (MFC) have led to simultaneous degradation of recalcitrant dyes and energy extraction from textile wastewater. Limited electron transfer capacity and hydrophobicity of electrode are the bottlenecks for enhancing the performance of MFC. Nanomaterials can provide surface functionalities for electron transfers and serve as catalyst for pollutant degradation. In this paper, magnetite nanoparticles functionalized with carbon dots (Fe3O4@CDs) were used to enhance the electron transfer capacity of the electrodes due to numerous surface-active functional groups of CDs and the reversible redox reaction of Fe2+/Fe3+. Polydopamine (PDA) was used as binder to coat Fe3O4@CDs onto the surface of carbon felt (CF) electrodes in a sono-chemical reaction, favoring to form biocompatible electrodes. Charge transfer resistance of Fe3O4@CDs@PDA-CF was 5.02Ω as compared to 293.34Ω of unmodified CF. Fe3O4@CDs@PDA-CF installed MFC could achieve almost 98% dye degradation efficiency within 48 h and 18.30 mW m-2 power output as compared to 77% dye degradation and 0.34 mW m-2 power output by unmodified CF electrode MFC. Moreover, metagenomic analysis of microbial consortia developed in Fe3O4@CDs@PDA-CF MFC showed enrichment of electrogenic and dye degrading microbial communities of Achromobacter. Delftia, Geobacter and Pseudomonas.