采用聚3,4-乙烯二氧噻吩(PEDOT)修饰石墨阳极,采用恒电位仪、扫描电子显微镜、能谱仪对其进行表征,并探讨其在U型微生物燃料电池(MFC)中影响海洋产电菌Shewanella sp. S2产电的机制.结果表明:电化学法合成的PEDOT呈片状覆盖在石墨表面,并带有一些颗粒状凸起(直径约200 nm).PEDOT修饰后,MFC表观内阻从471 Ω下降到390 Ω; 稳定期的电流密度(173.6 mA/m2)是未修饰MFC(74.4 mA/m2)的2.33倍.扫描电镜结果显示,PEDOT修饰显著提高了产电菌在阳极表面的吸附量.由于电极表面的粗糙度远小于细菌尺寸,推测MFC产电能力的提高主要是由于PEDOT与产电菌间的电荷相互作用而不是电极表面粗糙度.
In this study,poly(3,4-ethylenedioxythiophene)(PEDOT)was used to modify the graphite anode.The modified graphite anode was characterized with potentiostat,scanning electron microscope(SEM),energy disperse spectroscopy(EDS)and its effects on current generation of U-shaped microbial fuel cells(MFCs)were evaluated.The results showed that PEDOT was electrochemically polymerized and covered mainly in a sheet-like form with 200 nm-size dots on the anode surface.Polarization tests of the MFCs showed that,compared with the unmodified anode,apparent internal resistance declined from 471 Ω to 390 Ω.Consequently,the current density at the plateau stage was enhanced greatly(by 2.33 times),i.e.,173.6 mA/m2 for PEDOT modified type vs. 74.4 mA/m2 for the unmodified type.SEM analysis showed that there were more Shewanella sp. S2 cells adsorbed on the anode surface of the PEDOT modified type than that of the unmodified type.The overall results confirmed that it was mainly the charge interaction between PEDOT and exoelectrogens rather than the roughness improving marine MFC current production,because the roughness of both modified and unmodified anodes were much smaller than the size of S2 cells.
