两类阴极菌群微生物燃料电池降解硝酸盐研究

Biocathode degradation of nitrate by two different cathode floras of microbial fuel cells

文章以硝酸盐溶液为阴极的电子受体,在阴极室中分别接种活性污泥混合菌和纯反硝化单菌株,构成生物阴极微生物燃料电池(microbial fuel cell,简称MFC)A-MFC和B-MFC。实验结果表明:在外接电阻为100Ω情况下,A-MFC和B-MFC最大输出电压分别为119.6mV和117.2mV,硝酸盐在B-MFC阴极室的平均反硝化速率为2.19mg/(L·d),比A-MFC中的平均反硝化速率1.86mg/(L·d)略高;扫描电镜观察到A-MFC和B-MFC的阴极碳布纤维丝表面形貌存在差异,A-MFC中碳布被孔状结构物覆盖,而B-MFC阴极碳布被片层状结构物所覆盖;同时发现A-MFC的阴极碳布循环伏安法CV曲线上均出现了明显的还原峰,表明A-MFC阴极碳布上的微生物进行了催化还原反应,而且阴极溶液均出现1对明显的氧化还原电对,说明阴极溶液中确实存在氧化还原介体进行微生物与电极间传递电子。

With the nitrate solution as the electron acceptor ,mixed bacteria from activated sludge and pure denitrifying bacteria were inoculated in the cathode chamber ,and two kinds of biocathode micro-bial fuel cells（MFCs） named A-MFC B-MFC were built .The experimental results showed that the maximum output voltages of A-MFC and B-MFC were 119.6 mV and 117.2 mV respectively when the external resistance was 100 Ω .The average denitrification rate in B-MFC was 2.19 mg/（L ＆#183; d） and the average denitrification rate in A-MFC was 1.86 mg/（L ＆#183; d） .The cathode carbon cloth surface morphology of A-MFC was different from that of B-MFC according to scanning electron microscope observation ,and the carbon cloth in A-MFC was covered by macroporous structure ,however the car-bon cloth in B-MFC was covered by lamellar structure .It was also found that there were an obvious reduction peak in the cyclic voltammetry（CV） curve of A-MFC cathode carbon cloth and an oxidation-reduction pair in the cathode solution of A-MFC .The results showed that there were catalytic reduc-tion reaction in A-MFC and there was electron transferring between microorganisms and cathode elec-trode in solution .