阴极硝化耦合阳极反硝化实现微生物燃料电池技术脱氮

微生物燃料电池(MFC)是一种将废水中化学能转化为电能的技术,近年来被证实可以用来同步脱氮。目前,NH4+-N的硝化与反硝化多是在MFC阴极室进行,其存在曝气条件下反硝化菌难以富集的问题,造成反硝化速度慢。为解决上述问题,本研究旨在构建一种基于阴离子交换膜的(AEM)MFC,即AEM-MFC,使阴极好氧硝化过程产生的NO2-与NO3-能通过阴离子交换膜迁移至厌氧阳极室,并在厌氧阳极室发生还原,使得反硝化不需在好氧阴极室进行。结果表明,当阴极投加200 mg/L NH4+-N时,AEM-MFC能在66 h完全去除总氮,而同样条件下基于阳离子交换膜(CEM)的MFC,即CEM-MFC,则需要26 d达到相同的脱氮效果。在阴极室投加不同浓度NH4+-N(从50到500 mg/L)条件下,AEM-MFC连续运行7个月,其产电与脱氮效果稳定。相比于传统生物脱氮方法,AEM-MFC不需要在运行过程中在加入酸或碱调节pH,所需COD/N较少,并能够同时回收电能。

Cathode nitrification coupled to anode denitrification for nitrogen removal in a dual-chamber microbial fuel cell using anion exchange membrane

The microbial fuel cell (MFC) technology has been demonstrated to be a promising method for nitrogen removal with simultaneous power generation;however,most of the previous studies concerned simultaneous nitrification and denitrification (SND) in the aerated cathode chamber of an MFC,whereas the enrichment of cathodic denitrifying bacteria in the presence of aeration was difficult.Here,we show the concept of SND that occurs in separate anode and cathode chambers,rather than in the same cathode chamber.Cathode nitrification coupled to anode denitrification for nitrogen removal was achieved in a MFC with the help of an anion-exchange membrane (AEM) which enabled nitrate and nitrite as a result of cathode nitrification to transfer from the aerobic cathode chamber to the anaerobic anode chamber.When the ammonium with a concentration of 200 NH4+-N mg/L was fed to the cathode chamber,the AEM-MFC allowed complete nitrogen removal within 66 hrs,significantly lower than the time of 26 days required for the MFC with a cation-exchange membrane (CEM-MFC) that was operated under the identical conditions.Moreover,the AEM-MFC was stably run over a seven-month period with successive feedings of ammonium with different concentrations (e.g.,from 50 to 500 NH4+-N mg/L),exhibiting insignificant variations in performance of nitrogen removal and power generation.The results showed that the AEM-MFC offers the pronounced advantages including no requirement of adding acids or alkalis for pH adjustment,less COD for denitrification and energy production as compared to the traditional biological method for nitrogen removal.