阳极材料对微生物燃料电池性能影响的研究

以石墨、碳纸、碳布和碳毡为阳极材料,研究不同材料在微生物燃料电池中的产电性能,并利用循环伏安法比较不同材料的电化学活性。结果表明:在电池性能方面,以石墨为阳极微生物燃料电池电压可达0.678V,输出功率为250mW/m2;碳毡电压达0.656V,输出功率204mW/m2,碳纸0.649V,输出功率156mW/m2;碳布最差,电压不稳定,输出功率56mW/m2。循环伏安曲线和电极材料表观吸附量:碳毡作为阳极材料,具有明显的氧化峰和还原峰,对导电微生物具有显著的吸附量,其次是石墨,碳纸次之,最差的是碳布。     

电极材料对微生物燃料电池处理老龄垃圾渗滤液性能的影响

以碳毡和碳布为电极材料,老龄垃圾渗滤液为阳极底物构建生物阴极型微生物燃料电池(MFC),考察碳毡和碳布分别作为阴极和阳极材料时对MFC明在阳极材料相同时,碳毡阴极MFC料相同时,碳布阳极MFC输出电压和功率密度最大(分别为294 mV、95.31 mW/m~3)、化学需氧量和氨氮去除率最大(分别为58.78%、74.38%);阳极、阴极均为碳布的MFC内阻最小(308Ω),阳极、阴极均为碳毡的MFC内阻最大(347Ω)。     

微生物燃料电池阳极材料研究进展

微生物燃料电池（microbial fuel cell,MFC）是一种新型的生物电化学装置,能将可生物降解有机物中的化学能直接转化成电能,而阳极材料性能是影响MFC性能的重要因素之一。通过对阳极材料进行改性和修饰可以有效地增大其比表面积、生物相容性等,以提高其微生物负载率和电子传递速率,进而提高MFC的产电性能。本文全面介绍和总结了近年来国内外关于微生物燃料电池阳极材料的研究进展,分析微生物燃料电池阳极材料在规模放大应用中存在的问题,并对微生物燃料电池阳极材料今后的发展方向进行了展望。     

单室微生物燃料电池产电特性研究

采用石墨板为阴极构建了单室空气阴极微生物燃料电池(MFC),以混合菌种接种,并以乙酸钠和碳酸氢钠为碳源,研究了该MFC在间歇运行条件下的产电性能、电池内阻情况和COD去除率。结果表明,最高输出电压随着周期数增加而增加,由0.075 9 V上升到0.200 6 V,最大输出功率密度为34.80 mW/m2;在一个运行周期内,电池内阻随着时间的延长而逐渐增大,由376.6Ω上升到682.0Ω,电池内阻的增大将导致输出电压降低。COD去除率由起始的49.23%达到最大值86.99%,说明此单室空气阴极微生物燃料电池在产电的同时处理污水的效果也较好。     

电极间距对单室微生物燃料电池处理老龄垃圾渗滤液性能的影响

以体积分数为60%的老龄垃圾渗滤液为单室无膜空气阴极微生物燃料电池底物,考察电极间距分别为1、2、3、4、5 cm时电池产电性能及底物中物污染物的去除效果。结果表明,间距为2 cm时输出电压和最大功率密度最大,间距为4 cm时输出电压和最大功率密度最小;电极间距为1～3 cm时电池内阻随电极间距的增大而增大,而电极间距大于3 cm时电池内阻随电极间距的增大而减小。电极间距为2 cm时,微生物燃料电池(MFC)对老龄垃圾渗滤液中化学需氧量(COD)和氨氮去除率最高;5个电池的库伦效率分别为35.6%、27.6%、35.4%、14.9%和14.9%,单室无膜空气阴极MFC可在一定程度上提高老龄垃圾渗滤液的可生化性。     

处理过的老龄垃圾渗滤液为阴极液的微生物燃料电池性能研究

处理过的老龄垃圾渗滤液与好氧污泥悬浊液的混合液按不同体积配比(0%、25%、50%、75%和100%),作为阴极液,构建生物阴极型微生物燃料电池(MFC),研究其产电特征以及对阳极底物和阴极液中污染物的处理效果。结果表明,处理过的老龄垃圾渗滤液作为阴极液时,MFC对化学需氧量(COD)和氨氮的去除率较其作为阳极液时分别提高2.27倍和42%。处理过的老龄垃圾渗滤液与好氧活性污泥悬浊液的混合液作为阴极液可提高MFC的产电性能和对污染物的去除效果。以体积比为75%的处理过的老龄垃圾渗滤液作为阴极液时,能显著提高MFC产电效果,输出电压和输出功率密度最大,分别为498 mV、295.2 mW/m~3,内阻最小为244Ω,阳极COD去除率最高为44.81%。     

MnO2为阴极催化剂的微生物燃料电池处理城市垃圾渗滤液研究

主要针对城市垃圾热解预处理过程所产生的渗滤液进行研究。首先改变城市垃圾堆放温度和堆放时间,发现城市垃圾于40℃堆放6 d后所得的渗滤液中生物需氧量(Biological Oxygen Demand,BOD)、氨氮浓度约为20800、1410 mg/L,B/C比、B/N比分别为0.32和14.8,营养物质较均衡,易于生化处理,且将其进行微生物燃料电池(Microbial Fuel Cell,MFC)处理时,电池可获得0.29 V的稳定输出电压。随后,以上述渗滤液为MFC阳极基质,考察廉价易得的Mn O2作为阴极催化剂对空气阴极单室MFC电池性能以及渗滤液中有机污染物去除率的影响。结果发现,由于Mn O2催化氧还原,加速了MFC阴极接受电子的速度,使得MFC电池性能有较大提高。其中,MFC的最大功率密度由0.16 W/m3提高到0.88 W/m3,而电池稳定输出电压明显升高至0.43 V,且阳极渗滤液中BOD和NH4+-N去除率也分别达72.9%和91.6%,比对照MFC分别提高8.1%和5.0%。     

外加直流电场对微生物燃料电池阳极微生物的影响研究

为考察外加直流电场作用对微生物燃料电池阳极微生物的影响,采用双室型MFC反应器,在启动开始时分别加以-5,-3,-1,0,+1,+3,+5 V的直流电场,作用时间依次取2 min,30 min,1 h,24 h。结果表明,外加直流电场能够对微生物燃料电池阳极室内微生物的生长产生影响,作用时间为30 min时效果较为明显,提高作用时间后效果变化不大;±1 V的电场强度作用促进微生物的生长;较低的直流电场(±1 V)作用能够促进微生物燃料电池的阳极生物挂膜,且负电场促进效果更好,而较高的直流电场(+3 V和±5 V)作用不利于甚至损害阳极生物挂膜。     

单室空气阴极微生物燃料电池处理模拟生活废水同步产电研究

以某生活污水处理站厌氧池活性污泥为混合菌种,以葡萄糖为模拟生活废水,构建单室微生物燃料电池.利用微生物燃料电池实验生活废水降解与同步产电.实验结果表明:当葡萄糖浓度控制10mmol·L-1,pH值为7,温度控制在35℃时,其输出电压最大为0.486V,COD去除率最高为46.11％.微生物燃料电池(MFC)具有最佳的电化学性能.     

污水反硝化除磷产电装置启动研究

反硝化除磷产电装置以连续流双污泥反硝化除磷工艺为基础,以厌氧池和中沉池分别作为微生物燃料电池的阳极室和阴极室,以模拟的生活污水作为处理对象。反硝化除磷产电装置稳定运行2个月后,COD、氨氮和磷的平均去除率分别为65.56%,57.16%和53.79%,最高去除率分别达到了75%,75%和65%,产生的电压和电流强度的平均值分别为0.58 V和6.31 m A,最高电压值达到了0.7 V。反硝化除磷产电装置的成功启动与运行,不仅去除了生活污水中的COD、氨氮和磷,同时产生了稳定的电能,实现了反硝化除磷与微生物燃料电池的耦合,为反硝化除磷产电工艺的深入研究奠定了基础。     

Enhanced current production of the anode modified by microalgae derived nitrogen-rich biocarbon for microbial fuel cells

In this study, nitrogen-rich biocarbon derived from carbonized Chlorella pyrenoidosa (CCP) was proposed to enhance the current generation from the anode of microbial fuel cells (MFCs). The results revealed that the carbon cloth decorated by CCP (CCP-CC) achieved the highest bioelectrocatalytic current density of 13.44 ± 0.34 A m⁻² after the successful startup, which was 12% and 22% higher than those with carbon black (CB-CC) and the bare carbon cloth (CC), respectively. The results can be attributed to the advantages of CCP-CC over CB-CC and CC in terms of a higher active biomass content, a much smaller charge transfer resistance resulting from the facilitated direct electron transfer due to the presence of N-containing functional groups in CCP and the enhanced mediated electron transfer caused by the larger surface area of the CCP-CC anode for the flavin mediator adsorption.     

High-capacity polyaniline-coated molybdenum oxide composite as an effective catalyst for enhancing the electrochemical performance of the microbial fuel cell

Microbial fuel cells (MFCs) are a promising technology, which can generate electrical energy by utilizing the organic compound as fuels through central metabolism system of exo-electrogenic bacteria. Anodes have been intensively explored for the development of high-performance MFCs as an alternative to conventional electrodes. Modified anodes were synthesized by the coating of molybdenum oxide (MoO₂) and polyaniline (PANI) composites on the carbon cloth (CC) surface. MoO₂/PANI electrocatalyst anodes have high capacitance and electrical conductivity, experimentally affirmed by cyclic voltammetry (CV)and charge-discharge analysis. The as-prepared modified anodes were found to efficiently enhance the performance of MFCs by facilitating the extracellular electron transfer from bacteria to the anode. MFCs with MoO₂/PANI (1:2 w/w) electrocatalyst anode delivered a maximum power density (PD) of 1101 mW/m², which was 7.8 times higher than unmodified CC anode. EIS results indicate that the composite MoO₂/PANI has also responsible for decreasing the interfacial charge transfer resistance which leads to the improvement in electron transfer between microbes and the modified anode. The results found in the present study will help in the design optimization of novel anode materials to deliver improved PD from MFCs.     

Landfill leachate: A promising substrate for microbial fuel cells

Landfill leachate emerges as a promising feedstock for microbial fuel cells (MFCs). In the present investigation, direct air-breathing cathode-based MFCs are fabricated to investigate the maximum open circuit potential from landfill leachate. Three MFCs that have different cathode areas are fabricated and studied for 17 days under open circuit conditions. The maximum open circuit voltage (OCV) of the cell is observed to be as high as 1.29 V which is the highest OCV ever reported in the literature using landfill leachate. The maximum cathode area specific power density achieved in the reactor is 1513 mW m^?2. Further studies are under progress to understand the origin of high OCV obtained from landfill leachate-based MFCs.     

Power generation and organics removal from wastewater using activated carbon nanofiber (ACNF) microbial fuel cells (MFCs)

Carbon-based materials are the most commonly used electrode material for anodes in microbial fuel cell (MFC), but are often limited by their surface areas available for biofilm growth and subsequent electron transfer process. This study investigated the use of activated carbon nanofibers (ACNF) as the anode material to enhance bacterial biofilm growth, and improve MFC performance. Qualitative and quantitative biofilm adhesion analysis indicated that ACNF exhibited better performance over the other commonly used carbon anodes (granular activated carbon (GAC), carbon cloth (CC)). Batch-scale MFC tests showed that MFCs with ACNF and GAC as anodes achieved power densities of 3.50 ± 0.46 W/m³ and 3.09 ± 0.33 W/m³ respectively, while MFCs with CC had a lower power density of 1.10 ± 0.21 W/m³ In addition, the MFCs with ACNF achieved higher contaminant removal efficiency (85 ± 4%) than those of GAC (75 ± 5%) and CC (70 ± 2%). This study demonstrated the distinct advantages of ACNF in terms of biofilm growth and electron transport. ACNF has a potential for higher power generation of MFCs to treat wastewaters.     

Three-dimensional graphitic mesoporous carbon-doped carbon felt bioanodes enables high electric current production in microbial fuel cells

Microbial fuel cells (MFCs) represent a new approach that can simultaneously enhance the treatment of waste streams and generate electricity. Although MFCs represent a promising technology for renewable energy production, they have not been successfully scaled-up mainly due to the relatively-low electricity generation and high cost associated with MFCs operation. Here, we investigated whether graphitic mesoporous carbon (GMC) decoration of carbon felt would improve the conductivity and biocompatibility of carbon felt anodes, leading to higher biomass attachment and electricity generation in MFCs fed with an organic substrate. To test this hypothesis, we applied 3 different GMC loading (i.e., 2, 5, and 10 mg/cm² of anode surface area) in MFCs compared to control MFCs (with pristine carbon felt electrodes). We observed that the internal resistances of modified anodes with GMC were 1.2–2.3-order of magnitude less than pristine carbon felt anode, leading to maximum power densities of 70.3, 33.3, and 9.8 mW/m² for 10, 5, and 2 mg/cm²-doped anode, respectively compared to only 3.8 mW/m² for the untreated carbon felt. High-throughput sequencing revealed that increasing the GMC loading rate was associated with enriching more robust anode-respiring bacteria (ARB) biofilm community. These results demonstrate that 3-D GMC-doped carbon felt anodes could be a potential alternative to other expensive metal-based electrodes for achieving high electric current densities in MFCs fed with organic substrates, such as wastewater. Most importantly, high electron transfer capability, strong chemical stability, low cost, and excellent mechanical strength of 3-D GMC-doped carbon felt open up new opportunities for scaling-up of MFCs using cheap and high-performance anodes.     

Pyrolyzing pyrite and microalgae for enhanced anode performance in microbial fuel cells

Developing low-cost and high-performance anodes is of great significance for wider applications of microbial fuel cells (MFCs). In this study, microalgae and pyrite were co-pyrolyzed (P/MC) and then coated on carbon felt (CF) with PTFE as a binder. P/MC modification resulted in increased electroactive surface area, superhydrophilicity and higher biocompatibility. Besides, the P/MC-CF anode reduced the charge transfer resistance from 35.1 Ω to 11.4 Ω. The highest output voltage and the maximum power density of the MFC equipped with the P/MC-CF anode were 657 mV and 1266.7 mW/m², respectively, which were much larger than that of the MFC with the CF anode (530 mV, 556.7 mW/m²). The P/MC-CF anode also displayed higher columbic efficiency (39.41%) than the CF anode (32.37%). This work suggests that pyrolyzing microalgae with pyrite is a promising method to enhance the performance of MFCs.     

Effect of hydrogen producing mixed culture on performance of microbial fuel cells

This study examined the influence of H₂-producing mixed cultures on improving power generation using air-cathode microbial fuel cells (MFCs) inoculated with heat-treated anaerobic sludge. The MFCs installed with graphite brush anode generated higher power than the MFCs with carbon cloth anode, regardless heat treatment of anaerobic sludge. When the graphite brush anode-MFCs were inoculated selectively with H₂-producing bacteria by heat treatment, power production was not improved (about 490 mW/m²) in batch mode operation, but for slightly increased in carbon cloth anode-MFCs (from 0.16 to 2.0 mW/m²). Although H⁺/H₂ produced from H₂-producing bacteria can contribute to the performance of MFCs, suspended biomass did not affect the power density or potential, but the Coulombic efficiency (CE) increased. A batch test shows that propionate and acetate were used effectively for electricity generation, whereas butyrate made a minor contribution. H₂-producing mixed cultures do not affect the improvement in power generation and seed sludge, regardless of the pretreatment, can be used directly for the MFC performance.     

Different modified multi-walled carbon nanotube–based anodes to improve the performance of microbial fuel cells

To clearly illustrate the activity effect of multi-walled carbon nanotubes (MWCNTs) and their functionality on anodic exoelectrogen in microbial fuel cells (MFCs), the growth of E. coli and anode biofilm on MWCNT-, MWCNTCOOH and MWCNTNH₂ modified anodes were compared with a bare carbon cloth anode. The activity effect was characterized by the amount of colony-forming units (CFUs), activity biomass, morphology of biofilms and cyclic voltammetric (CV). The results showed that MWCNTs, MWCNT-COOH and MWCNT-NH₂ exhibited good biocompatibility on exoelectrogenic bacteria. The performance of MFCs were improved through the introduction of MWCNT-modified anodes, especially in the presence of COOH/NH₂ groups. The MFCs with the MWCNTCOOHmodified anode achieved a maximum power density of 560.40 mW/m², which was 49% higher than that obtained with pure carbon cloth. In conclusion, the positive effects of MWCNTs and their functionality were evaluated for promoting biofilm formation, biodegradation and electron transfer on anodes. Specifically, the MWCNTCOOHmodified anode demonstrated the largest application potential for the development of MFCs.     

β-FeOOH modified carbon monolith anode derived from wax gourd for microbial fuel cells

The preparation of high-performance anode materials is of significance for enhanced power generation in microbial fuel cells (MFCs). Herein, porous carbon monolith was prepared by simple freeze drying of wax gourd and subsequent pyrolysis (WGC). β-FeOOH was coated on WGC to further improve the performance of the anode (β-FeOOH/WGC). The maximum power density of the MFCs with WGC and β-FeOOH/WGC anode was 913.9 and 1355.1 mW/m² respectively, which was much higher than that of the control (558.2 mW/m²). WGC possessed three-dimensional pore structure, nitrogen and oxygen-containing functional groups, which endowed it with satisfactory bacterial loading. Improved MFC performance after β-FeOOH modification could be ascribed to two aspects: β-FeOOH enhanced the electrochemical activity and decrease the transfer resistance; β-FeOOH was conducive to exoelectrogens formation. This study demonstrated that the synthesis of β-FeOOH modified carbon monolith anode offered an efficient route to enhance the power generation of MFCs.