Urea removal coupled with enhanced electricity generation in single-chambered microbial fuel cells

High concentration of total ammonia nitrogen (TAN) in the form of urea is known to inhibit the performance of many biological wastewater treatment processes. Microbial fuel cells (MFCs) have great potential for TAN removal due to its unique oxic/anoxic environment. In this study, we demonstrated that increased urea (TAN) concentration up to 3940 mg/L did not inhibit power output of single-chambered MFCs, but enhanced power generation by 67% and improved coulombic efficiency by 78% compared to those obtained at 80 mg/L of TAN. Over 80% of nitrogen removal was achieved at TAN concentration of 2630 mg/L. The increased nitrogen removal coupled with significantly enhanced coulombic efficiency, which was observed for the first time, indicates the possibility of a new electricity generation mechanism in MFCs: direct oxidation of ammonia for power generation. This study also demonstrates the great potential of using one MFC reactor to achieve simultaneous electricity generation and urea removal from wastewater.

     

以养殖废水为底料的微生物燃料电池产电性能与水质净化效果

以养殖场沼泥为接种物,构建了乙二胺、三氯化铁改性碳毡阳极的单室无膜微生物燃料电池,探讨了2种阳极改性电池的产电规律,考察了其去除养殖废水中COD、氨氮的效果以及臭味的表观性状变化。结果表明,以葡萄糖为底物时,乙二胺、三氯化铁改性阳极微生物燃料电池在启动20 d和22 d后分别达到稳定,输出电压分别为0.514 V和0.527V(外阻为500Ω),对应输出功率密度分别为332 mW/m2和349 mW/m2。逐渐增大废水投加比例至原水时,2个电池的最大功率密度分别为208 mW/m2和158 mW/m2,COD去除率分别为85%和78%,氨氮去除率分别为52%和45%。此外,养殖废水的臭味去除效果明显。因此,构建的2种改性阳极微生物燃料电池可以利用养殖废水产电,同时使水质得到一定程度的净化。     

不同阳极微生物燃料电池产电性能的比较

微生物燃料电池在处理废水的同时可以产生电能,有希望同时解决废水再利用和能量再产生的问题。采用单室无膜空气阴极微生物燃料电池,处理模拟生活污水,探讨MFC处理模拟废水的效果。研究了以碳布(MFC1)、碳布负载碳纳米管(MFC2)、碳纳米管(MFC3)和泡沫镍(MFC4)作为4种不同的阳极材料,对MFC系统的启动、内阻和产电特性进行比较。结果表明,4种不同阳极MFC在水力停留时间24 h的条件下,对COD有很好的去除作用,其中MFC2的COD去除效率最大,为91.4%。在不影响MFC系统处理废水效果的前提下,实验得到4种阳极MFC系统中MFC2具有最小的内阻,为173.7Ω;并且其功率密度也大于其他3种MFC,达到401.2 mW/m2。     

单室微生物燃料电池处理含铜模拟废水

为了降低废水中重金属的含量,研究了空气阴极单室微生物燃料电池对模拟废水中Cu（II）的去除效果。考察了铜的初始浓度、初始pH值和外加电阻等单因子的影响,从Cu（II）去除率及电压输出等方面进行考核,确定最佳去除条件：SMFC的最大耐受浓度为12.5 mg·L-1,最适Cu（II）还原去除的初始pH值为6.0和低电阻500 Ω。SMFC出水Cu（Ⅱ）浓度低于0.5 mg·L-1,达到《城镇污水处理厂污染物排放标准》（GB18918-2002）中总铜排放标准,拓展了生物电化学系统系统在去除重金属离子废水方面的应用。     

Microbial community composition and electricity generation in cattle manure slurry treatment using microbial fuel cells: effects of inoculum addition

Environmental Science and Pollution Research - Microbial fuel cell (MFC) is a sustainable technology to treat cattle manure slurry (CMS) for converting chemical energy to bioelectricity. In this...     

MFC-MBR耦合系统运行效果及产电性能

为了解决膜生物反应器（MBR）运行成本高、膜污染的问题,本研究建立了一个微生物燃料电池（MFC）-MBR耦合系统,通过MFC回收污水中的能量,同时控制膜污染。研究结果表明,耦合系统对COD和NH3-N的去除率分别为（94.6±3.0）%和（90.9±6.9）%,出水水质稳定。由于MFC的耦合作用,使MBR的运行周期由18 d延长至36 d,膜污染得到了明显的减缓。耦合系统中MFC产电性能稳定,电流密度稳定在5.7 A/m3,最大功率密度达到了928.0 mW/m3,循环伏安法（CV）表明,阴极附着的微生物具有良好的电化学催化作用。MFC-MBR耦合系统将污水中的化学能转化为电能从而实现了膜污染的减缓及能量的回收,显示出巨大的发展前景。     

Monitoring a changing Arctic: Recent advancements in the study of sea ice microbial communities

Sea ice continues to decline across many regions of the Arctic, with remaining ice becoming increasingly younger and more dynamic. These changes alter the habitats of microbial life that live within the sea ice, which support healthy functioning of the marine ecosystem and provision of resources for human-consumption, in addition to influencing biogeochemical cycles (e.g. air–sea CO₂ exchange). With the susceptibility of sea ice ecosystems to climate change, there is a pressing need to fill knowledge gaps surrounding sea ice habitats and their microbial communities. Of fundamental importance to this goal is the development of new methodologies that permit effective study of them. Based on outcomes from the DiatomARCTIC project, this paper integrates existing knowledge with case studies to provide insight on how to best document sea ice microbial communities, which contributes to the sustainable use and protection of Arctic marine and coastal ecosystems in a time of environmental change.Supplementary InformationThe online version contains supplementary material available at 10.1007/s13280-021-01658-z.     

Hydrogen fuel and fuel cell technology for cleaner future: a review

Environmental Science and Pollution Research - One of the main problems facing our planetary bodies is unexpected and sudden climate change due to continuously increasing global energy demand,...     

铁碳布空气阴极微生物燃料电池的产电性能

使用铁代替铂作为阴极催化剂,制作含铁碳布空气阴极并构建单室MFC(Fe-C-ACMFC)。以乙酸钠为燃料,通过稳态放电法和循环伏安测试等测试手段,分析了不同铁含量对Fe-C-ACMFC产电性能的影响以及性能最优Fe-C-ACM-FC的连续运行稳定性。结果表明,随着铁含量的增加,Fe-C-ACMFC启动期开路电压(OCV)逐步提高,达到峰值后,随着铁含量的增加而降低;同样,Fe-C-ACMFC极化性能和功率密度等产电性能也随铁含量的增加先升高再降低;当铁含量为0.7 mg/cm2时,MFC的产电性能最优,最大开路电压为593 mV,表观内阻为89Ω,最大功率密度达到12 907 mW/m3,并且经循环伏安测试,电池放电容量几乎没有变化,表明Fe-C-ACMFC的性能比较稳定,能够长期运行。由于铁催化剂价格远远低于铂催化剂,因此,铁碳布空气阴极MFC更利于推广应用。     

共基质下微生物燃料电池同步脱色甲基橙与产电性能

采用双室方形微生物燃料电池(MFC),以葡萄糖作为共基质,研究了共基质浓度对典型偶氮染料甲基橙在MFC阳极室中脱色效率及同步产电的影响。结果表明,在0~1.5 g/L浓度范围内,共基质浓度越大,甲基橙脱色率、COD去除率和最大输出电压越高。在共基质浓度为1.5 g/L,进水甲基橙为300 mg/L的条件下,8 h的脱色率高达95%,且在1 000 Ω外电阻下,最大输出电压达到662 mV;在无共基质条件下,8 h内对300 mg/L甲基橙的脱色率仅为7.5%,最大输出电压仅达到140 mV。厌氧对照实验表明,甲基橙在MFC中可以实现加速脱色,反应8 h后甲基橙在MFC中的脱色率提高了57%。该研究为开发新型MFC降解偶氮染料废水技术提供了理论依据。     

四室微生物燃料电池同步脱氮除碳及产电性能

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NH₄⁺-N质量浓度分别为1 100 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%。     

Alteration of sediment organic matter in sediment microbial fuel cells

The alteration of physico-chemical properties of sediment organic matter (SOM) incubated under current-harvesting conditions as well as no-current producing conditions over 120 days using sediment microbial fuel cell systems was examined. The SOM was microbially oxidized under anaerobic conditions with an electrode serving as a terminal electron acceptor. It was found that SOM around the electrochemically-active electrodes became more humified, aromatic, and polydispersed, and had a higher average molecular weight, along with its partial degradation and electricity generation compared to that for the original sediment. These changes in SOM properties were analogous to those commonly observed in the early stages of the SOM diagenetic process (i.e. humification). Such a humification-like process was evidently more stimulated when electrical current was produced than no-current condition. These new findings associated with microbially-catalyzed electricity generation may present a potential for the energy-efficient remediation, monitoring, and/or management of the geo-environment.     

不同阴极对微生物燃料电池产电性能的影响比较

阴极催化性能及材料对微生物燃料电池(microbial fuel cells,MFCs)的产电特性及制造成本有很大影响。本研究选用金属铂(Pt)、活性炭作为催化剂、聚四氟乙烯(PTFE)和道康宁1-2577作为阴极的扩散层、碳布和不锈钢网作为阴极的基体材料制备得4种阴极,分别考察了相应MFC的产电性能和阴极特性。结果表明,采用传统Pt催化剂+PTFE扩散层+碳布制备成的阴极(Pt-PTC),MFC的最大输出电压为560 mV,最大功率密度为808 mW/m2,而采用活性炭+道康宁1-2577+不锈钢网制备成的阴极(AC-DCS),MFC的最大输出电压为510 mV,最大功率密度为726 mW/m2,两者的MFC产电性能极为接近。SEM结果表明,活性炭催化层表面和道康宁1-2577扩散层分别比Pt催化层及PTFE扩散层的更均匀光滑。阴极线性伏安测定结果表明,AC-DCS与Pt-PTC的电化学氧化性能较为接近。AC-DCS阴极成本仅为Pt-PTC的1/300左右,是一种低成本扩大化生产MFC阴极的新方法。     

Simultaneous bioelectricity generation and decolorization of methyl orange in a two-chambered microbial fuel cell and bacterial diversity

The objectives of this study were to investigate the simultaneous bioelectricity generation and decolorization of methyl orange (MO) in the anode chamber of microbial fuel cells (MFCs) in a wide concentration range (from 50 to 800 mg L^?1) and to reveal the microbial communities on the anode after the MFC was operated continuously for more than 6 months using MO-glucose mixtures as fuel. Interestingly, the added MO played an active role in the production of electricity. The maximum voltage outputs were 565, 658, 640, 629, 617, and 605 mV for the 1 g L^?1 glucose with 0, 50, 100, 200, 300, and 500 mg L^?1 of MO, respectively. The results of three groups of comparison experiments showed that accelerated decolorization of methyl orange (MO) was achieved in the MFC as compared to MFC in open circuit mode and MFC without extra carbon sources. The decolorization efficiency decreased with an increase of MO concentration in the studied concentration range for the dye load increased. A 454 high-throughput pyrosequencing revealed the microbial communities. Geobacter genus known to generate electricity was detected. Bacteroidia class, Desulfovibrio, and Trichococcus genus, which were most likely responsible for degrading methyl orange, were also detected.     

微波预处理污泥上清液为燃料的微生物燃料电池的影响因素研究

以微波预处理的剩余污泥上清液做为燃料,经过30 d成功地启动了单室无膜燃料电池.考察了可能影响输出功率密度的相关因素.结果表明,电池阳极面积越大,输出功率密度反而越小.阴阳极距离从5 cm缩小到0.5 cm时,输出功率密度先增加后降低,在距离为2 cm时,输出功率密度达到最大值282.7 mW/m2,说明阴阳极距离过近...     

串联补给式微生物燃料电池加速处理含铜废水

微生物燃料电池（microbial fuel cells,MFC）可用于处理有机废水并同时处理污水中的重金属。为了对MFC处理含铜废水进行优化,采用了KMnO4-MFC与Cu-MFC串联,通过前者产生的较高电压对后者处理含铜废水过程提供电压和功率的补给并获得额外电能,结果表明,KMnO4-MFC在KMnO4浓度为0.5、1、2 g·L-1时输出最大功率密度分别为288、433、700 mW·m-2,而Cu-MFC在Cu2+浓度为10 mg·L-1时最大功率密度仅为218.75 mW·m-2,二者串联能够明显加快Cu-MFC对Cu2+的回收速率,串联时Cu2+的回收率可达98%,24 h回收率可达91.7%,与单独Cu-MFC相比速率提高1倍。串联后,该种方法在加速铜回收过程的同时还能获得额外的电能,其最高输出功率可达143 mW。     

石墨烯/碳化钴钼复合材料作为微生物燃料电池阴极催化剂的研究

用改良Hummers法和碳热还原法分别制备了石墨烯和碳化钴钼。用透射电镜（TEM）、扫描电子显微镜（SEM）和X射线衍射仪（XRD）表征了材料的形貌和结构。用循环伏安（CV）表征了其氧还原（ORR）催化性能,结果表明,复合材料的氧还原峰电流和起峰电位均大大优于单一材料。旋转圆盘电极（RDE）实验表明复合材料的氧还原反应为高效的四电子转移过程。含有6 mg·cm-2石墨烯/碳化钴钼复合材料作为阴极催化剂的微生物燃料电池（MFCs）最大功率密度为418 mW·m-2,达到商业铂碳的68.3%。因此,廉价的石墨烯/碳化钴钼复合材料作为MFCs阴极氧还原催化剂具有巨大的应用潜力。     

纳米铁对微生物燃料电池启动的影响

设置3组不同阳极底物的微生物燃料电池（microbial fuel cell,MFC）：无添加污泥（对照组）、含化学合成零价纳米铁的污泥（c-nZVI组）和含绿色合成零价纳米铁的污泥（g-nZVI组）,拟探究不同来源零价纳米铁（nZVI）对MFC启动的影响。3组MFC经由5个周期启动,实验结果表明,在c-nZVI组和g-nZVI组的启功阶段,高浓度的绿色合成零价纳米铁和化学合成零价纳米铁均对MFC的输出电压产生抑制作用,当MFC成功启动后,零价纳米铁对MFC的输出电压影响不明显。此外,COD去除率、SEM和电化学表征数据表明,绿色合成零价纳米铁相比于化学合成零价纳米铁在电极表面富集程度、对电极表面性质改变以及产电菌活性的抑制作用更弱。     

高盐高浓度废水微生物燃料电池的启动

通过加入不同比例的乙醇辅助高盐高浓度废水条件下微生物燃料电池(microbial fuel cells,MFC)的启动实验,发现在加入乙醇的微生物燃料电池的启动,较不加入乙醇的微生物燃料电池的启动更容易。分别进行了乙醇加入量(经换算后所得COD值)为原水COD值的0%、5%、10%、15%和20%这5组实验,通过比较得出,乙醇加入量为原水COD值10%左右时,启动最佳。     

Enhanced nickel removal and synchronous bioelectricity generation based on substrate types in microbial fuel cell coupled with constructed wetland: performance and microbial response

Environmental Science and Pollution Research - In this study, an attempt was made to clarify the impact of substrates on the microbial fuel cell coupled with constructed wetland (CW-MFC) towards...