| Rapidly developing bioelectrochemical systems,such as microbial fuel cells（MFCs）,are part of a diverse platform of future sustainable energy and chemical production technologies.The MFCs is a promising tool for the degradation of organic pollutants and simultaneous electricity recovery,the characteristics of anode has been regarded as one of the key factors to influence the MFC performances.Currently,the inferior anode is unable to match with cathode’s high oxygen reduction reaction performance,which makes it hard to satisfy the requirements for practical applications.Hence,more efforts will be taken to explore the anode performance.This study has been carried out based on anode biocompatibility with electrical conductivity and electron transfer efficiency,biofilm prefabrication,the different conditional regulation as well as the application on MFC has been included.The results are as followed:（1）A biocompatible,conductive,and high electron transfer ability anode was fabricated by electrodepositing polypyrrole/anthraquinone-2,6-disulphonic disodium salt onto nitric acid-soaked carbon felt.Results showed that the multi-modified anode outperformed the pristine one in biomass,electrical conductivity,and exchange current density with better performance between 2.4 and 3.3 times.The multi-modified anode（applied with 0.12 C/cm2 total charge density）showed the highest peak current density（2.86 mA）,the largest amount of biomass loading（0.44 mg/cm2）,the most favoured electrical conductivity（0.33 S/cm）,and exchange current density(3.65×10-3 A/m2),as a result,the maximum power density of the MFC equipped with the anode delivered a 2.2-fold increase over that of the control（1060.3 mW/m2 vs.477.6 mW/m2）,and thus has great potential to be used as an anode for high-power MFCs.It is proposed that integrating biocompatibility with electrical conductivity and electron transfer efficiency through multi-modification could form high-performance anode.（2）Based on simple consecutive electrochemical selection procedure,anode biofilms acclimatization and enriching process can be accelerated and ultimately realized.The results showed that the performance of anodes were closely related with the ways and time（duration）of prefabrication,while the prefabricated anode CF-8v outperformed the control one in cyclic voltammetry,Tafel plot,and electrochemical impedance spectroscopy tests.The maximum power density（1163.07 mW/m2）of the MFC equipped with the anode CF-8v delivered a 1.79-fold increase over that of the control;also,the maximum output 0.54 V,1.42 times higher than the unfabricated one,can be achieved in 60 min.An analysis of the three-dimensional metabolic structure of the biofilms over time showed that both types of biofilms developed a live outer-layer that covered a dead inner-core.This two-layer structure appeared to be mostly a result of relatively low anodic current densities compared to other studies.During biofilm development,the live layer reached a constant thickness,whereas dead cells continued to accumulate near the electrode surface.This result indicated that only the live outer-layer of biofilm was responsible for current generation and suggested that the dead inner-layer continued to function as an electrically conductive matrix. |
