四室微生物燃料电池同步脱氮除碳及产电性能

Simultaneous nitrogen and carbon removal and electricity generation in fourchamber microbial fuel cell

微生物燃料电池近年来被证实可以用来同步脱氮,然而微生物燃料电池中阴阳极室通常以不同成分的污水作为底物。为了实现废水脱氮,往往需要进行出水调配或停曝等复杂的操作。为解决上述问题,本研究构建了阴极硝化耦合阳极反硝化的四室微生物燃料电池(four chamber microbial fuel cell,FC-MFC),阳极室与阴极室之间用阳离子交换膜(cation exchange membrane,CEM)与阴离子交换膜(anion exchange membrane,AEM)进行交替分隔。在浓度差作用下离子进行定向迁移,最终实现阳极室有机物和氨氮的同步去除。探讨了阳极COD(即进水碳氮比)对FC-MFC产电及污染物去除效果的影响,并分析FC-MFC的氮去除途径。结果表明:随着阳极室COD的增加,各MFC模块的产电周期、峰值输出电压和最大功率密度随之增加,同时阳极室COD和TN的去除率也呈上升趋势,该系统对高碳氮比污水具有良好的抵抗负荷。当进水COD和NH_(4)^(+)-N质量浓度分别为1100 mg·L^(−1)和100 mg·L^(−1)时,4个MFC模块的峰值输出电压介于526~619 mV,最大功率密度为103.47~121.00 mW·m^(−2),阳极室COD去除率和TN去除率分别高达94%和96%以上。氮去除途径分析结果表明,阳极室微生物吸附代谢作用、阴极室内源反硝化、阴极室通过AEM迁移至后序位阳极室进行反硝化过程分别贡献了25.96%~25.97%、0.91%~5.18%、68.87%~73.20%。

The microbial fuel cell(MFC)has been demonstrated to be a promising method for nitrogen removal.However,in traditional MFC,the anode and cathode chambers utilize distinct wastewater components as substrates,requiring intricate processes,such as effluent allocation or stopping aeration,to achieve nitrogen removal.Here,we show the concept of simultaneous nitrification and denitrification that occurs in separate anode and cathode chambers rather than in the same cathode chamber.Cathodic nitrification coupled to anode denitrification for nitrogen removal was achieved in a four-chamber microbial fuel cell(FC-MFC).This system employed cation exchange and anion exchange membranes to alternate between anode and cathode chambers.This promoted the directional migration of ions under concentration gradients,which facilitated the concurrent removal of organic matter and ammonia in the anode chamber.The impact of anode COD on MFC power generation and pollutant removal efficiency was investigated and the nitrogen removal pathway of this FC-MFC system was examined.The results showed that the power generation cycles,peak output voltages and maximum power densities of each MFC module increased with the increase of anode COD,along with the increased removal rates of COD and TN in the anode chamber.Notably,this system demonstrated an excellent resilience to high carbon-nitrogen ratio wastewater.When the influent COD and NH_(4)^(+)-N concentrations were 1100 mg·L^(−1)and 100 mg·L^(−1),respectively,the peak output voltages were 526~619 mV and maximum power densities were 103.47~121.00 mW·m^(−2)for four MFC modules,the COD and TN removal rates in the anode chamber were over 94%and 96%,respectively.Nitrogen removal pathway analysis revealed that microbial adsorption and metabolism in the anode chamber,endogenous denitrification in the cathode chamber,and the AEM-mediated denitrification process in the post-order anode chamber contributed 25.96%~25.97%,0.91%~5.18%,and 68.87%~73.20%to nitrogen removal,respectively.