好氧生物阴极型微生物燃料电池的同时硝化和产电的研究

Simultaneous Electricity Generation and Nitrification in a Microbial Fuel Cell with Aerobic Biocathode

在两室型微生物燃料电池的阴极室接种硝化菌实现了同时硝化和产电.硝化过程和产电过程在同一区域实现,不仅能够充分利用曝气的溶解氧,节省曝气能源消耗,而且硝化过程产生的额外的质子,有效地避免了产电过程所造成的阴极pH值升高.运行稳定期间MFC的最大电流和最大功率密度分别为47mA和45.50W/m3,当进水氨氮浓度为153.4mg/L时,硝化速率为5.98mg/(L·d).硝化菌会与产电菌竞争溶解氧,但当溶解氧浓度控制在3.5～5.0mg/L时,硝化过程未对产电产生明显影响.无缓冲溶液的条件下,加入氨氮时的阴极电势比未加入氨氮时的阴极电势高124mV,且阴极电势变化的阶段与氨氮降解的过程是一一对应的.H+离子的理论计算表明,硝化过程产生的H+离子(8.14×10-3mol)与产电过程消耗H+离子(8.54×10-3mol)数量相当,证实了硝化作用中产生的H+离子能够补偿阴极室由于产电造成的H+离子的消耗,维持系统pH值的稳定.

The present study demonstrated simultaneous electricity generation and nitrification in a two-chamber microbial fuel cell （MFC） with aerobic biocathode seeded with nitrifying bacteria.Nitrification process and power production simultaneously happening in the same region not only saved energy consumption of aeration by making the best use of oxygen,but also produced additional proton by nitrification process,which effectively prevented alkaline at the cathode caused by power production.The maximum nominal current and maximum power density were 47 mA and 45.50 W /m3,respectively.The NH 4＋-N removal rate was 5.98 mg /（L·d） when NH 4＋-N concentration was 153.4 mg /L.The nitrifying bacteria competed with electrochemically-active bacteria for oxygen.However,the nitrification was of little effect on bioelectricity production when oxygen concentration was as high as 3.5-5.0 mg /L.The average cathodic voltage with addition of NH 4＋-N was 124 mV higher than that of without NH 4＋-N addition when no buffer was added in the medium.Cathodic variations were corresponded with nitrification process.The theoretical calculation of H＋ ion proved that,the additional H＋ ion produced by nitrification process （8.14 × 10-3 mol） was similar with the H＋ ion consumed by power production process （8.54 × 10-3 mol）,which confirmed that nitrification could compensate the pH gradient caused by bioelectricity process in the cathode,and maintained the stable pH value to a certain extent.