纳米Fe3O4对沼液MFC产电特性与有机物降解影响

Effect of nano-Fe3O4 on electrical production characteristics andorganic degradation of methane MFC

摘要:

为了提高微生物燃料电池（MFC）对沼液中有机质的降解和产电效率，将纳米Fe3O4与MFC结合，对比研究了纳米Fe3O4以Fe3O4@生物炭和Fe3O4@碳毡两种不同介入方式对MFC性能的影响。结果表明，两种方式均可成功启动MFC，且产电效率远高于无纳米Fe3O4介入的空白实验，最高电压分别为699和707 mV，最高电压均持续时间长达10 d。Fe3O4@碳毡与Fe3O4@生物炭介入下MFC最大功率密度分别为700和578 mW/m2，相较于未使用纳米Fe3O4的MFC提高了43%和31%。将Fe3O4@碳毡作为阳极电极得到的化学需氧量（COD）降解率最高，为51.76%；直接投加Fe3O4@生物炭对NH4+-N的降解影响最大，投加Fe3O4@生物炭后NH4+-N含量由（6800.14±57.86） mg/L降至（689.14±37.29） mg/L，NH4+-N降解率达到89.87%。纳米Fe3O4参与的MFC微生物群落结构合理，两种介入方式均刺激了主要水解细菌梭菌纲（Clostridia）的生长富集。随着纳米Fe3O4的位置变化，Clostridia的相对丰度在以Fe3O4@生物炭和Fe3O4@碳毡介入的MFC中分别达到61.11%、50.98%。二者的电活化细菌中β-变形菌纲（Betaproteobacteria）含量最高，并且在反应后碳毡上发现了反硝化细菌芽孢八叠球菌属（Sporosarcina）。

Abstract:

In order to improve the degradation of organics in biogas slurry and electricity production of Microbial Fuel Cell (MFC), the combination of nano-Fe3O4 with MFC was proposed, loading nano-Fe3O4 on anode carbon felt (Fe3O4@carbon felt) and loading nano-Fe3O4 on biochar (Fe3O4@biochar) into the anode chamber. The performance of MFCs were comparatively studied. The results showed that the MFC both loading methods could successfully start, and the power production efficiency was much higher than that of the blank experiment without the intervention of nano-Fe3O4, with the maximum voltage of 699 and 707 mV, respectively, and the both maximum voltage value lasted up to 10 d. The maximum power density was increased by 43% and 31% in the Fe3O4@carbon felt (700 mW/m2) and Fe3O4@biochar (578 mW/m2) approaches, respectively, compared to that MFC without the use of Fe3O4 nanoparticles. The highest chemical oxygen demand (COD) degradation rate of 51.76% was obtained by using Fe3O4@carbon felt as the anode electrode; the direct application of Fe3O4@biochar had the greatest effect on the degradation of ammonium nitrogen, which decreased from (6800.14±57.86) mg/L to (689.14±37.29) mg/L after the application of Fe3O4@biochar, with a degradation rate of 89.87%.The microbial community structure of the MFC with the participation of nano-Fe3O4 tended to be rationalized, and both participation methods stimulated the growth of the main hydrolytic bacteria Clostridia. With the position of nano-Fe3O4 changing, the relative abundance of Clostridia in the MFC with Fe3O4@biochar directly inputting into the anode chamber and the MFC with Fe3O4@carbon felt as the anode electrode reached to 61.11% and 50.98%, respectively. Both had the highest content of Betaproteobacteria in electroactivation and denitrifying bacteria Sporosarcina was found on the post-reaction carbon felt.