Microbial fuel cell(MFC)technology has emerged as an effective solution for energy insecurity and bioremediation.However,identifying suitable components(particularly separators or membranes)with the required propertie...Microbial fuel cell(MFC)technology has emerged as an effective solution for energy insecurity and bioremediation.However,identifying suitable components(particularly separators or membranes)with the required properties,such as low cost and high performance,remains challenging and restricts practical application.Commercial membranes,such as Nafion,exhibit excellent performance in MFC.However,these membranes have high production costs,which considerably increase the overall MFC unit cell cost.Among the numerous types,the separators or membranes developed from biopolymers and naturally occurring earthen sources have proven to be a novel and efficient concept due to their natural abundance,cost-effectiveness(approximately$20 m^(-2),$5 m^(-2),and$1 kg-1for biopolymers,ceramics,and earthensources,respectively),structural properties,proton transportation,manufacturing and modification ease,and environmental friendliness.In this review,we emphasize cost-effective renewable green materials(biopolymers,bio-derived materials,and naturally occurring soil,clay,ceramics or minerals)for MFC applications for the first time.Biopolymers with good thermal,mechanical,and water retention properties,sustainability,and environmental friendliness,such as cellulose and chitosan,are typically preferred.Furthermore,the modification or introduction of various functional groups in biopolymers to enhance their functional properties and scale MFC power density is explored.Subsequently,separator/membrane development using various bio-sources(such as coconut shells,banana peels,chicken feathers,and tea waste ash)is described.Additionally,naturally occurring sources such as clay,montmorillonite,and soils(including red,black,rice-husk,and Kalporgan soil)for MFC were reviewed.In conclusion,the existing gap in MFC technology was filled by providing recommendations for future aspects based on the barriers in cost,environment,and characteristics.展开更多
Surface electropositivity and low internal resistance are important factors to improve the anode performance in microbial fuel cells(MFCs). Nitrogen doping is an effective way for the modification of traditional carbo...Surface electropositivity and low internal resistance are important factors to improve the anode performance in microbial fuel cells(MFCs). Nitrogen doping is an effective way for the modification of traditional carbon materials. In this work, heat treatment and melamine were used to modify carbon felts to enhance electrogenesis capacity of MFCs. The modified carbon felts were characterized using X-ray photoelectron spectroscopy(XPS), scanning electron microscope(SEM), atomic force microscopy(AFM)and malvern zeta potentiometer. Results show that the maximum power densities under heat treatment increase from 276.1 to 423.4 m W/m^2(700 °C) and 461.5 m W/m^2(1200 °C) and further increase to472.5 m W/m^2(700 °C) and 515.4 m W/m^2(1200 °C) with the co-carbonization modification of melamine.The heat treatment reduces the material resistivity, improves the zeta potential which is beneficial to microbial adsorption and electron transfer. The addition of melamine leads to the higher content of surface pyridinic and quaternary nitrogen and higher zeta potential. It is related to higher MFCs performance. Generally, the melamine modification at high temperature increases the feasibility of carbon felt as MFCs' s anode materials.展开更多
Nitrogen and sulfur co-doped porous nanocarbon (ZIF-C-N-S) catalyst was successfully synthesized derived from ZIF-8 and thiourea precursors.The electrochemical measurements indicate that the as-obtained ZIF-C-N-S cata...Nitrogen and sulfur co-doped porous nanocarbon (ZIF-C-N-S) catalyst was successfully synthesized derived from ZIF-8 and thiourea precursors.The electrochemical measurements indicate that the as-obtained ZIF-C-N-S catalyst exhibits higher electrocatalytic activity for oxygen reduction reaction (ORR) in alkaline electrolyte and superior durability-longer than commercial Pt/C catalyst.The enhancment of electrocatalytic activity mainly be come from the open pore structure,large specific surface area as well as the synergistic effect resulted from the co-doping of N and S atoms.In addition,the ZIF-C-N-S catalyst is also used as the air cathode catalyst in the microbial fuel cell (MFC) device.The maximum power density and stable output voltage of ZIF-C-N-S based MFC are 1315 mW/m2 and 0.48 V,respectively,which is better than that of Pt/C based MFC.展开更多
Microbial fuel cells(MFCs)have gained remarkable attention as a novel wastewater treatment that simultaneously generates electricity.The low activity of the oxygen reduction reaction(ORR)remains one of the most critic...Microbial fuel cells(MFCs)have gained remarkable attention as a novel wastewater treatment that simultaneously generates electricity.The low activity of the oxygen reduction reaction(ORR)remains one of the most critical bottlenecks limiting the development of MFCs.To date,although research on biochar as an electrocatalyst in MFCs has made tremendous progress,further improvements are needed to make it economically practical.Recently,biochars have been considered to be ORR electrocatalysts with developmental potential.In this review,the ORR mechanism and the essential requirements of ORR catalysts in MFC applications are introduced.Moreover,the focus is to highlight the material selection,properties,and preparation of biochar electrocatalysts,as well as the evaluation and measurement of biochar electrodes.Additionally,in order to provide comprehensive information on the specific applications of biochars in the field of MFCs,their applications as electrocatalysts,are then discussed in detail,including the uses of nitrogen-doped biochar and other heteroatom-doped biochars as electrocatalysts,poisoning tests for biochar catalysts,and the cost estimation of biochar catalysts.Finally,profound insights into the current challenges and clear directions for future perspectives and research are concluded.展开更多
Anode modification plays a key role in higher power output in marine sediment microbial fuel cells(MSMFCs).A low-molecular organosilicon compound(3-aminopropyltriethoxysilane)was grafted onto the surface of carbon fel...Anode modification plays a key role in higher power output in marine sediment microbial fuel cells(MSMFCs).A low-molecular organosilicon compound(3-aminopropyltriethoxysilane)was grafted onto the surface of carbon felt using chemical method and a composite modified anode was prepared through organic ligands coordination Fe^(3+)for better electro-chemical per-formance.Results show that the biofilm resistance of the composite modified anode(2707Ω)is 1.3 times greater than that of the unmodified anode(2100Ω),and its biofilm capacitance also increases by 2.2 times,indicating that the composite modification pro-motes the growth and attachment of electroactive bacteria on the anode.Its specific capacitance(887.8 Fm^(−2))is 3.7 times higher than that of unmodified anode,generating a maximum current density of 1.5Am^(−2).In their Tafel curves,the composite modified anodic exchange current density(5.25×10^(−6)Acm^(−2))is 5.8 times bigger than that of unmodified anode,which suggests that the electro-chemical activity of redox,anti-polarization ability and electron transfer kinetic activity are significantly enhanced.The marine sediment microbial fuel cell with the composite modified anode generates the higher power densities than the blank(203.8mWm^(−2) versus 45.07mWm^(−2)),and its current also increases by 4.4 times.The free amino groups on the anode surface expands a creative idea that the modified anode ligates the natural Fe(Ⅲ)ion in sea water in the MSMFCs for its higher power output.展开更多
For the performance improvement of microbial fuel cells(MFCs),the anode becomes a breakthrough point due to its influence on bacterial attachment and extracellular electron transfer(EET).On other level,carbon material...For the performance improvement of microbial fuel cells(MFCs),the anode becomes a breakthrough point due to its influence on bacterial attachment and extracellular electron transfer(EET).On other level,carbon materials possess the following features:low cost,rich natural abundance,good thermal and chemical stability,as well as tunable surface properties and spatial structure.Therefore,the development of carbon materials and carbon-based composites has flourished in the anode of MFCs during the past years.In this review,the major carbon materials used to decorate MFC anodes have been systematically summarized,based on the differences in composition and structure.Moreover,we have also outlined the carbon material-based hybrid biofilms and carbon material-modified exoelectrogens in MFCs,along with the discussion of known strategies and mechanisms to enhance the bacteria-hosting capabilities of carbon material-based anodes,EET efficiencies,and MFC performances.Finally,the main challenges coupled with some exploratory proposals are also expounded for providing some guidance on the future development of carbon material-based anodes in MFCs.展开更多
Microbial fuel cell (MFC) is one of renewable biofuel production technology that directly converts biomass to electricity. Cellulosic biomass is particularly attractive renewable resources for its low cost and abundan...Microbial fuel cell (MFC) is one of renewable biofuel production technology that directly converts biomass to electricity. Cellulosic biomass is particularly attractive renewable resources for its low cost and abundance and neutral carbon balance. However, methanogenesis remains as a major factor limiting MFC performance. The current study reports that saponin addition at 0.05</span><span style="white-space:nowrap;font-family:Verdana;">%</span><span style="font-family:Verdana;"> w/v dose to anolyte in MFCs inhibited methanogenesis and improves power generation and cellulose fermentation. Mediator-less two chamber H-type MFCs were prepared using </span><span><span style="font-family:Verdana;">rumen fluid as anode inocula at 20</span><span style="white-space:nowrap;font-family:Verdana;">%</span><span style="font-family:Verdana;"> v/v of anolyte to convert finely ground pine tree (Avicel) at 2</span><span style="white-space:nowrap;font-family:Verdana;">%</span><span style="font-family:Verdana;">, w/v to electricity. Saponin was added to the anode of MFC at 0.005</span><span style="white-space:nowrap;font-family:Verdana;">%</span><span style="font-family:Verdana;"> or 0.05</span><span style="white-space:nowrap;font-family:Verdana;">%</span><span style="font-family:Verdana;"> v/v dosage for treatment. </span></span><span style="font-family:Verdana;">MFC power and current across an external resistor were measured daily for 10d. On d10, collected gases from anode compartment were measured for total gas volume and analyzed for gas composition on gas chromatography. Supplementation of saponin to MFC at 0.005</span><span style="white-space:nowrap;font-family:Verdana;">%</span><span style="font-family:Verdana;"> did not have any effects on electricity generation or biogas production and composition. Saponin at 0.05% dose reduced 10</span><span style="white-space:nowrap;font-family:Verdana;">%</span><span style="font-family:Verdana;"> of methane production and increased 40</span><span style="white-space:nowrap;font-family:Verdana;">%</span><span style="font-family:Verdana;"> of CO</span><sub><span style="font-family:Verdana;">2</span></sub><span style="font-family:Verdana;"> production and 6.4</span><span style="white-space:nowrap;font-family:Verdana;">%</span><span style="font-family:Verdana;"> of total gas production for 10d MFC operation. Voltage across resistor prior to treatment addition (d0) was 164.75 ± 9.07 mV. In control group, voltage across resistor did not change (P = 0.9153) with time course and mean was 167.8 ± 8.20 mV ranged from 157 to 174.5 mV during 10d operation. In 0.05</span><span style="white-space:nowrap;font-family:Verdana;">%</span><span style="font-family:Verdana;"> Saponin group, voltage across resistor increased (P <</span></span><span style="font-family:Verdana;"> 0</span><span style="font-family:""><span style="font-family:Verdana;">.0001) after d2 and mean was 187.3 ± 4.30 mV ranged between 161.5 and 204.0 mV and the 10d mean of voltage across resistor in 0.05</span><span style="white-space:nowrap;font-family:Verdana;">%</span><span style="font-family:Verdana;"> Saponin was greater (P <</span></span><span style="font-family:Verdana;"> 0</span><span style="font-family:""><span style="font-family:Verdana;">.0001) than in control group. 0.05</span><span style="white-space:nowrap;font-family:Verdana;">%</span><span style="font-family:Verdana;"> Saponin also had greater voltage across resistor at d5 (P = 0.0030) and d6 (P = 0.0246) than control. End point potential increased (P <</span></span><span style="font-family:Verdana;"> 0</span><span style="font-family:""><span style="font-family:Verdana;">.0001) in 0.05</span><span style="white-space:nowrap;font-family:Verdana;">%</span><span style="font-family:Verdana;"> Saponin after d2. 0.05</span><span style="white-space:nowrap;font-family:Verdana;">%</span><span style="font-family:Verdana;"> Saponin had greater (P < 0.05) end point potentials than control at d1, d4, d7, d10, and also 10d mean was greater (731.9 vs 606.5 mV;P <</span></span><span style="font-family:Verdana;"> 0</span><span style="font-family:""><span style="font-family:Verdana;">.0001) in 0.05</span><span style="white-space:nowrap;font-family:Verdana;">%</span><span style="font-family:Verdana;"> Saponin. Power density increased (P <</span></span><span style="font-family:Verdana;"> 0</span><span style="font-family:""><span style="font-family:Verdana;">.0001) after d2 in 0.05</span><span style="white-space:nowrap;font-family:Verdana;">%</span><span style="font-family:Verdana;"> Saponin. 0.05</span><span style="white-space:nowrap;font-family:Verdana;">%</span><span style="font-family:Verdana;"> Saponin MFCs had greater (P < 0.05) power density than control at d5 and d6, and also a greater (P <</span></span><span style="font-family:Verdana;"> 0</span><span style="font-family:Verdana;">.0001) overall mean of 10d operation. The current study provides strong background for potential use of saponin and saponin containing natural resources for methanogenesis inhibitor and cellulolysis enhancer in MFC and also cellulolysis reactors.展开更多
This work proposed a simple and efficient approach for synthesis of durable and efficient non-precious metal oxygen reduction reaction(ORR) electro-catalysts in MFCs. The rod-like carbon nanotubes(CNTs)were formed on ...This work proposed a simple and efficient approach for synthesis of durable and efficient non-precious metal oxygen reduction reaction(ORR) electro-catalysts in MFCs. The rod-like carbon nanotubes(CNTs)were formed on the Fe–N/SLG sheets after a carbonization process. The maximum power density of1210 ± 23 m W·m^(-2) obtained with Fe–N/SLG catalyst in an MFC was 10.7% higher than that of Pt/C catalyst(1080 ± 20 mW ·m^(-2)) under the same condition. The results of RDE test show that the ORR electron transfer number of Fe–N/SLG was 3.91 ± 0.02, which suggested that ORR catalysis proceeds through a four-electron pathway. The whole time of the synthesis of electro-catalysts is about 10 h, making the research take a solid step in the MFC expansion due to its low-cost, high efficiency and favorable electrochemical performance. Besides, we compared the electrochemical properties of catalysts using SLG, high conductivity graphene(HCG, a kind of multilayer graphene) and high activity graphene(HAG, a kind of GO) under the same conditions, providing a solution for optimal selection of cathode catalyst in MFCs.The morphology, crystalline structure, elemental composition and ORR activity of these three kinds of Fe–N/C catalysts were characterized. Their ORR activities were compared with commercial Pt/C catalyst.It demonstrates that this kind of Fe–N/SLG can be a type of promising highly efficient catalyst and could enhance ORR performance of MFCs.展开更多
The focus of microbial fuel cell research in recent years has been on the development of materials,microbes,and transfer of charges in the system,resulting in a substantial improvement in current density and improved ...The focus of microbial fuel cell research in recent years has been on the development of materials,microbes,and transfer of charges in the system,resulting in a substantial improvement in current density and improved power generation.The cathode is generally recognized as the limiting factor due to its high-distance proton transfer,slow oxygen reduction reaction(ORR),and expensive materials.The heterogeneous reaction determines power gen-eration in MFC.This comprehensive review describes-recent advancements in the development of cathode mate-rials and catalysts associated with ORR.The recent studies indicated the utilization of different metal oxides,the ferrite-based catalyst to overcome this bottleneck.These studies conclude that some cathode materials,in parti-cular,graphene-based conductive polymer composites with non-precious metal catalysts provide substantial ben-efits for sustainable development in the field of MFCs.Furthermore,it also highlights the potentiality to replace the conventional platinum air cathode for the large-scale production of the next generation of MFCs.It was evi-dent from the experiments that cathode catalyst needs to be blended with conductive carbon materials to make cathode conductive and efficient for ORR.This review discusses various antifouling strategies for cathode biofoul-ing and its effect on the MFC performance.Moreover,it also depicts cost estimations of various catalysts essential for further scale-up of MFC technology.展开更多
Microbial fuel cells(MFCs)are an attractive innovation at the nexus of energy and water security for the future.MFC utilizes electrochemically active microorganisms to oxidize biodegradable substrates and generate bio...Microbial fuel cells(MFCs)are an attractive innovation at the nexus of energy and water security for the future.MFC utilizes electrochemically active microorganisms to oxidize biodegradable substrates and generate bioelectricity in a single step.The material of the anode plays a vital role in increasing the MFC’s power output.The anode in MFC can be upgraded using nanomaterials providing benefits of exceptional physicochemical properties.The nanomaterials in anode gives a high surface area,improved electron transfer promotes electroactive biofilm.Enhanced power output in terms of Direct current(DC)can be obtained as the consequence of improved microbe-electrode interaction.However,several limitations like complex synthesis and degeneration of property do exist in the development of nanomaterial-based anode.The present review discusses different renewable nanomaterial applied in the anode to recover bioelectricity in MFC.Carbon nanomaterials have emerged in the past decade as promising materials for anode construction.Composite materials have also demonstrated the capacity to become potential anode materials of choice.Application of a few transition metal oxides have been explored for efficient extracellular electron transport(EET)from microbes to the anode.展开更多
Microbial fuel cells(MFCs),as a sustainable and promising technology to solve both environmental pollution and energy shortage,have captured tremendous attention.The conversion efficiency of chemical energy contained ...Microbial fuel cells(MFCs),as a sustainable and promising technology to solve both environmental pollution and energy shortage,have captured tremendous attention.The conversion efficiency of chemical energy contained in organic waste or wastewater to electricity via microbial metabolism strongly depends on the performance of each functional unit,including the anode,cathode and separator/membrane used in MFCs.Therefore,significant attention has been paid toward developing advanced functional materials to enhance the performance of each unit or provide new featured functions.This review paper provides a comprehensive review on recent achievements and advances in the modification and development of functional materials for MFC systems,including 1)the development of functional anode materials for enhanced microbial compatibilities as well as electron transfer capabilities,2)the development of cost-effective separators/membranes such as ion exchange membrane,porous membrane,polymer electrolyte membrane and composite membrane,and 3)the development of functional cathode catalysts to decrease the over-potential and enhance the electrocatalytic efficiency for oxygen reduction reaction in order to substitute the common costly Pt catalyst.The challenges and outlooks of functional materials for MFC applications are also discussed.展开更多
This paper compared the degradation efficiency of sludge organic matters and electric-production by two typical microbial fuel cells——dual-chamber microbial fuel cell(DMFC)and single chamber air cathode microbial fu...This paper compared the degradation efficiency of sludge organic matters and electric-production by two typical microbial fuel cells——dual-chamber microbial fuel cell(DMFC)and single chamber air cathode microbial fuel cell(SAMFC),and the variations of sludge protein,polysaccharide and ammonia nitrogen within the systems were also investigated.The results showed that the concentration of sludge soluble chemical oxygen demand,protein and carbohydrate of DMFC are higher than these of SAMFC during the systems operation,while DMFC can achieve a better ammonia nitrogen removal than SAMFC.Under the same operation condition,the stable voltage output of DMFC and SAMFC is 0.61 V and 0.37 V;the maximum power density of DMFC and SAMFC is 2.79 W/m3and 1.25 W/m3;TCOD removal efficiency of DMFC and SAMFC is 34.14%and 28.63%for 12 d,respectively.Meanwhile,DMFC has a higher coulomb efficiency than SAMFC,but both are less than5%.The results showed that DMFC present a better performance on sludge degradation and electric-production.展开更多
Microbial fuel cell (MFC) is one of the clean and sustainable energy technologies, often referred to as renewable energy, and directly chemical energy contained in organic matter into electrical energy by using the ca...Microbial fuel cell (MFC) is one of the clean and sustainable energy technologies, often referred to as renewable energy, and directly chemical energy contained in organic matter into electrical energy by using the catalytic activity of microorganisms. Cellulosic biomass is a particularly attractive renewable resource for its abundant supply at low cost and its neutral carbon balance. However, methanogenesis had been negatively linked to anaerobic cellulosic power generation in MFCs. Ginseng root is a saponin-rich plant material and red ginseng marc (RGM) has not been reused as a high-value resource for industry although its residue contained both electron donors and saponin, the potential power generation enhancers for MFC. In this study, RGM was supplemented into MFC to evaluate its effects on methanogenesis and power generation. Two-chamber H-type MFCs were established using rumen fluid as anolyte to ferment cellulose at 2% (w/v). RGM, the residue from the steam and press process for red ginseng beverage preparation, was freeze-dried and ground to pass 0.5 mm sieve and added to the anode of MFC at 1% (w/v;Exp. 1) or 0.1% (Exp. 2) dose for treatment. Open circuit voltage, voltage and current across an external resistor were measured daily for 10d. On d10 of operation, collected biogases were measured for total gas production and analyzed for its components. In Exp. 1, power density was between 44.0 and 97.2 with an average of 83.8 mW/m<sup>2</sup> in 1% RGM MFCs and was between 45.2 and 76.3 with an average of 61.5 mW/m<sup>2</sup> in control. In Exp. 2, power density was between 44.8 and 75.6 with an average of 60.9 mW/m<sup>2</sup> in 0.1% RGM MFCs and was between 45.1 and 54.1 with an average of 49.7 mW/m<sup>2</sup> in control. Total gas production for 10d was 563 and 523 mL for RGM and control, respectively, in Exp 1, and was 546 and 477 mL for RGM and control, respectively, in Exp 2. Methane took up 58.6 and 67.9% of total gas for RGM and control, respectively, in Exp 1, and 59.1 and 67.3% of total gas for RGM and control, respectively, in Exp 2. Both greater (P < 0.05) power generation less (P < 0.05) methane proportion in RGM MFCs in both Exp. 1 and 2 strongly supports the potential use of red ginseng marc as MFC supplements.展开更多
Methane has been demonstrated to be a feasible substrate for electricity generation in microbial fuel cells(MFCs)and denitrifying anaerobic methane oxidation(DAMO).However,these two processes were evaluated separately...Methane has been demonstrated to be a feasible substrate for electricity generation in microbial fuel cells(MFCs)and denitrifying anaerobic methane oxidation(DAMO).However,these two processes were evaluated separately in previous studies and it has remained unknown whether methane is able to simultaneously drive these processes.Here we investigated the co-occurrence and performance of these two processes in the anodic chamber of MFCs.The results showed that methane successfully fueled both electrogenesis and denitrification.Importantly,the maximum nitrate removal rate was significantly enhanced from(1.4±0.8)to(18.4±1.2)mg N/(L·day)by an electrogenic process.In the presence of DAMO,the MFCs achieved a maximum voltage of 610 mV and a maximum power density of 143±12 mW/m^(2).Electrochemical analyses demonstrated that some redox substances(e.g.riboflavin)were likely involved in electrogenesis and also in the denitrification process.High-throughput sequencing indicated that the methanogen Methanobacterium,a close relative of Methanobacterium espanolae,catalyzed methane oxidation and cooperated with both exoelectrogens and denitrifiers(e.g.,Azoarcus).This work provides an effective strategy for improving DAMO in methane-powered MFCs,and suggests that methanogens and denitrifiers may jointly be able to provide an alternative to archaeal DAMO for methane-dependent denitrification.展开更多
Increasing energy demands and environmental pollution concerns press for sustainable and environmentally friendly technologies.Soil microbial fuel cell(SMFC)technology has great potential for carbon-neutral bioenergy ...Increasing energy demands and environmental pollution concerns press for sustainable and environmentally friendly technologies.Soil microbial fuel cell(SMFC)technology has great potential for carbon-neutral bioenergy generation and self-powered electrochemical bioremediation.In this study,an in-depth assessment on the effect of several carbon-based cathode materials on the electrochemical performance of SMFCs is provided for the first time.An innovative carbon nanofibers electrode doped with Fe(CNFFe)is used as cathode material in membrane-less SMFCs,and the performance of the resulting device is compared with SMFCs implementing either Pt-doped carbon cloth(PtC),carbon cloth,or graphite felt(GF)as the cathode.Electrochemical analyses are integrated with microbial analyses to assess the impact on both electrogenesis and microbial composition of the anodic and cathodic biofilm.The results show that CNFFe and PtC generate very stable performances,with a peak power density(with respect to the cathode geometric area)of 25.5 and 30.4 mW m^(−2),respectively.The best electrochemical performance was obtained with GF,with a peak power density of 87.3 mW m^(−2).Taxonomic profiling of the microbial communities revealed differences between anodic and cathodic communities.The anodes were predominantly enriched with Geobacter and Pseudomonas species,while cathodic communities were dominated by hydrogen-producing and hydrogenotrophic bacteria,indicating H_(2)cycling as a possible electron transfer mechanism.The presence of nitrate-reducing bacteria,combined with the results of cyclic voltammograms,suggests microbial nitrate reduction occurred on GF cathodes.The results of this study can contribute to the development of effective SMFC design strategies for field implementation.展开更多
Despite more than a decade of study,there are still significant obstacles to overcome before graphene can be successfully produced on a large scale for commercial use.Chemical oxidation of graphite to produce graphene...Despite more than a decade of study,there are still significant obstacles to overcome before graphene can be successfully produced on a large scale for commercial use.Chemical oxidation of graphite to produce graphene oxide(GO),followed by a subsequent reduction process to synthesize reduced graphene oxide(rGO),is considered the most practical method for mass production.Microorganisms,which are abundant in nature and inexpensive,are one of the potential green reductants for rGO synthesis.However,there is no recent review discussing the reported microbial reduction of GO in detail.To address this,we present a comprehensive review on the reduction of GO by a range of microorganisms and compared their efficacies and reaction conditions.Also,presented were the mechanisms by which microorganisms reduce GO.We also reviewed the recent advancements in using microbially reduced GO as the anode and cathode material in the microbial fuel cell(MFC)and algal biophotovoltaics(BPV),as well as the challenges and future directions in microbial fuel cell research.展开更多
To find suitable wetland plants for constructed wetland-microbial fuel cells(CW-MFCs),four commonly used wetland plants, including Canna indica, Cyperus alternifolius L., Acorus calamus, and Arundo donax, were investi...To find suitable wetland plants for constructed wetland-microbial fuel cells(CW-MFCs),four commonly used wetland plants, including Canna indica, Cyperus alternifolius L., Acorus calamus, and Arundo donax, were investigated for their electrogenic performance and physiological changes during non-growing seasons. The maximum power output of12.82 mW/m^2 was achieved in the A. donax CW-MFC only when root exudates were being released. The results also showed that use of an additional carbon source could remarkably improve the performance of electricity generation in the C. indica and A. donax CW-MFCs at relatively low temperatures(2–15°C). However, A. calamus withered before the end of the experiment, whereas the other three plants survived the winter safely, although their relative growth rate values and the maximum quantum yield of PSII(Fv/Fm) significantly declined, and free proline and malondialdehyde significantly accumulated in their leaves.On the basis of correlation analysis, temperature had a greater effect on plant physiology than voltage. The results offer a valuable reference for plant selection for CW-MFCs.展开更多
Pore structure plays critical roles in electrode kinetics but very challenging to tailor porous nanowires with rationally distributed pore sizes in a bioelectrochemical system.Herein a hierarchically porous nanowires-...Pore structure plays critical roles in electrode kinetics but very challenging to tailor porous nanowires with rationally distributed pore sizes in a bioelectrochemical system.Herein a hierarchically porous nanowires-material is delicately tuned for an optimal pore structure by adjusting the weight percentage of SiO_(2)-hard template in an electrospinning precursor solution.The asprepared optimal electrospinning nanowires further used as an anode of microbial fuel cells(MFCs),delivering a maximum output power density of 1,407.42 mW·m^(−2)with 4.24 and 10 times higher than that of the non-porous fiber and carbon cloth anode,respectively.The great enhancement is attributed to the rational pore structure which offers the largest surface area while the rich-mesopores well match with the size of electron mediators for a high density of catalytic centers.This work provides thoughtful insights to design of hierarchical porous electrode for high-performance MFCs and other bioelectrochemical system devices.展开更多
Developing low-cost,efficient oxygen reduction reaction(ORR)catalysts to replace Pt-based materials is urgently required for the application of Zn-air batteries(ZABs)and microbial fuel cells(MFCs).In this work,meso-mi...Developing low-cost,efficient oxygen reduction reaction(ORR)catalysts to replace Pt-based materials is urgently required for the application of Zn-air batteries(ZABs)and microbial fuel cells(MFCs).In this work,meso-microporous carbon fibers with tunable defect density were synthesized by carrageenan fibers.A highly defective carbon fiber(HDCFs)was produced which exhibited an outstanding ORR catalytic activity,reaching to the half-wave potential of 0.841 and 0.44 V in alkaline and neutral electrolytes,respectively.These HDCFs can also act as highly efficient air cathodes for ZABs(delivered potential of 0.69 V and power density of 220 mW cm^(–2) at 300 mA cm^(–2))and MFCs(high power density of 69.7 mW cm^(–2)).Simulation by the density functional theory indicated that a high density of defections in a carbon based framework can remarkably modulate the electrical properties.For instance the charge entrapments in the carbon active sites may reduce the energy barrier of ORR.展开更多
Microbial fuel cell(MFC) is an advanced bioelectrochemical technique that can utilize biomass materials in the process of simultaneously generating electricity and biodegrading or bio transforming toxic pollutants fro...Microbial fuel cell(MFC) is an advanced bioelectrochemical technique that can utilize biomass materials in the process of simultaneously generating electricity and biodegrading or bio transforming toxic pollutants from wastewater. The overall performance of the system is largely dependent on the efficiency of the anode electrode to enhance electron transportation. Furthermore, the anode electrode has a significant impact on the overall cost of MFC setup. Hence, the need to explore research focused towards developing cost-effective material as anode in MFC. This material must also have favourable properties for electron transportation. Graphene oxide(GO) derivatives and its modification with nanomaterials have been identified as a viable anode material. Herein, we discussed an economically effective strategy for the synthesis of graphene derivatives from waste biomass materials and its subsequent fabrication into anode electrode for MFC applications. This review article offers a promising approach towards replacing commercial graphene materials with biomass-derived graphene derivatives in a view to achieve a sustainable and commercialized MFC.展开更多
基金supported by the Korean Ministry of Trade,Industry,and Energy(Project number:20008490)the Core Research Support Center for Natural products and Medical Materials(CRCNM)in Yeungnam University。
文摘Microbial fuel cell(MFC)technology has emerged as an effective solution for energy insecurity and bioremediation.However,identifying suitable components(particularly separators or membranes)with the required properties,such as low cost and high performance,remains challenging and restricts practical application.Commercial membranes,such as Nafion,exhibit excellent performance in MFC.However,these membranes have high production costs,which considerably increase the overall MFC unit cell cost.Among the numerous types,the separators or membranes developed from biopolymers and naturally occurring earthen sources have proven to be a novel and efficient concept due to their natural abundance,cost-effectiveness(approximately$20 m^(-2),$5 m^(-2),and$1 kg-1for biopolymers,ceramics,and earthensources,respectively),structural properties,proton transportation,manufacturing and modification ease,and environmental friendliness.In this review,we emphasize cost-effective renewable green materials(biopolymers,bio-derived materials,and naturally occurring soil,clay,ceramics or minerals)for MFC applications for the first time.Biopolymers with good thermal,mechanical,and water retention properties,sustainability,and environmental friendliness,such as cellulose and chitosan,are typically preferred.Furthermore,the modification or introduction of various functional groups in biopolymers to enhance their functional properties and scale MFC power density is explored.Subsequently,separator/membrane development using various bio-sources(such as coconut shells,banana peels,chicken feathers,and tea waste ash)is described.Additionally,naturally occurring sources such as clay,montmorillonite,and soils(including red,black,rice-husk,and Kalporgan soil)for MFC were reviewed.In conclusion,the existing gap in MFC technology was filled by providing recommendations for future aspects based on the barriers in cost,environment,and characteristics.
文摘Surface electropositivity and low internal resistance are important factors to improve the anode performance in microbial fuel cells(MFCs). Nitrogen doping is an effective way for the modification of traditional carbon materials. In this work, heat treatment and melamine were used to modify carbon felts to enhance electrogenesis capacity of MFCs. The modified carbon felts were characterized using X-ray photoelectron spectroscopy(XPS), scanning electron microscope(SEM), atomic force microscopy(AFM)and malvern zeta potentiometer. Results show that the maximum power densities under heat treatment increase from 276.1 to 423.4 m W/m^2(700 °C) and 461.5 m W/m^2(1200 °C) and further increase to472.5 m W/m^2(700 °C) and 515.4 m W/m^2(1200 °C) with the co-carbonization modification of melamine.The heat treatment reduces the material resistivity, improves the zeta potential which is beneficial to microbial adsorption and electron transfer. The addition of melamine leads to the higher content of surface pyridinic and quaternary nitrogen and higher zeta potential. It is related to higher MFCs performance. Generally, the melamine modification at high temperature increases the feasibility of carbon felt as MFCs' s anode materials.
基金the National Natural Science Foundation of China(No.51472034)the Opening Project of Key Laboratory of Optoelectronic Chemical Materials and Devices,Ministry of Education,Jianghan University(No.JDGD-201806)。
文摘Nitrogen and sulfur co-doped porous nanocarbon (ZIF-C-N-S) catalyst was successfully synthesized derived from ZIF-8 and thiourea precursors.The electrochemical measurements indicate that the as-obtained ZIF-C-N-S catalyst exhibits higher electrocatalytic activity for oxygen reduction reaction (ORR) in alkaline electrolyte and superior durability-longer than commercial Pt/C catalyst.The enhancment of electrocatalytic activity mainly be come from the open pore structure,large specific surface area as well as the synergistic effect resulted from the co-doping of N and S atoms.In addition,the ZIF-C-N-S catalyst is also used as the air cathode catalyst in the microbial fuel cell (MFC) device.The maximum power density and stable output voltage of ZIF-C-N-S based MFC are 1315 mW/m2 and 0.48 V,respectively,which is better than that of Pt/C based MFC.
基金This study was supported by the National Natural Science Foundation of China(No.41877372,31570504)the Natural Key R&D Program of China(No.2019YFC1804102).
文摘Microbial fuel cells(MFCs)have gained remarkable attention as a novel wastewater treatment that simultaneously generates electricity.The low activity of the oxygen reduction reaction(ORR)remains one of the most critical bottlenecks limiting the development of MFCs.To date,although research on biochar as an electrocatalyst in MFCs has made tremendous progress,further improvements are needed to make it economically practical.Recently,biochars have been considered to be ORR electrocatalysts with developmental potential.In this review,the ORR mechanism and the essential requirements of ORR catalysts in MFC applications are introduced.Moreover,the focus is to highlight the material selection,properties,and preparation of biochar electrocatalysts,as well as the evaluation and measurement of biochar electrodes.Additionally,in order to provide comprehensive information on the specific applications of biochars in the field of MFCs,their applications as electrocatalysts,are then discussed in detail,including the uses of nitrogen-doped biochar and other heteroatom-doped biochars as electrocatalysts,poisoning tests for biochar catalysts,and the cost estimation of biochar catalysts.Finally,profound insights into the current challenges and clear directions for future perspectives and research are concluded.
基金This work was supported by the National Natural Sci-ence Foundation of China(No.22075262).
文摘Anode modification plays a key role in higher power output in marine sediment microbial fuel cells(MSMFCs).A low-molecular organosilicon compound(3-aminopropyltriethoxysilane)was grafted onto the surface of carbon felt using chemical method and a composite modified anode was prepared through organic ligands coordination Fe^(3+)for better electro-chemical per-formance.Results show that the biofilm resistance of the composite modified anode(2707Ω)is 1.3 times greater than that of the unmodified anode(2100Ω),and its biofilm capacitance also increases by 2.2 times,indicating that the composite modification pro-motes the growth and attachment of electroactive bacteria on the anode.Its specific capacitance(887.8 Fm^(−2))is 3.7 times higher than that of unmodified anode,generating a maximum current density of 1.5Am^(−2).In their Tafel curves,the composite modified anodic exchange current density(5.25×10^(−6)Acm^(−2))is 5.8 times bigger than that of unmodified anode,which suggests that the electro-chemical activity of redox,anti-polarization ability and electron transfer kinetic activity are significantly enhanced.The marine sediment microbial fuel cell with the composite modified anode generates the higher power densities than the blank(203.8mWm^(−2) versus 45.07mWm^(−2)),and its current also increases by 4.4 times.The free amino groups on the anode surface expands a creative idea that the modified anode ligates the natural Fe(Ⅲ)ion in sea water in the MSMFCs for its higher power output.
基金the financial support from the National Natural Science Foundation of China(21804070,21974125)the starting fund from City University of Hong Kong and the 111 Project(D20015).
文摘For the performance improvement of microbial fuel cells(MFCs),the anode becomes a breakthrough point due to its influence on bacterial attachment and extracellular electron transfer(EET).On other level,carbon materials possess the following features:low cost,rich natural abundance,good thermal and chemical stability,as well as tunable surface properties and spatial structure.Therefore,the development of carbon materials and carbon-based composites has flourished in the anode of MFCs during the past years.In this review,the major carbon materials used to decorate MFC anodes have been systematically summarized,based on the differences in composition and structure.Moreover,we have also outlined the carbon material-based hybrid biofilms and carbon material-modified exoelectrogens in MFCs,along with the discussion of known strategies and mechanisms to enhance the bacteria-hosting capabilities of carbon material-based anodes,EET efficiencies,and MFC performances.Finally,the main challenges coupled with some exploratory proposals are also expounded for providing some guidance on the future development of carbon material-based anodes in MFCs.
文摘Microbial fuel cell (MFC) is one of renewable biofuel production technology that directly converts biomass to electricity. Cellulosic biomass is particularly attractive renewable resources for its low cost and abundance and neutral carbon balance. However, methanogenesis remains as a major factor limiting MFC performance. The current study reports that saponin addition at 0.05</span><span style="white-space:nowrap;font-family:Verdana;">%</span><span style="font-family:Verdana;"> w/v dose to anolyte in MFCs inhibited methanogenesis and improves power generation and cellulose fermentation. Mediator-less two chamber H-type MFCs were prepared using </span><span><span style="font-family:Verdana;">rumen fluid as anode inocula at 20</span><span style="white-space:nowrap;font-family:Verdana;">%</span><span style="font-family:Verdana;"> v/v of anolyte to convert finely ground pine tree (Avicel) at 2</span><span style="white-space:nowrap;font-family:Verdana;">%</span><span style="font-family:Verdana;">, w/v to electricity. Saponin was added to the anode of MFC at 0.005</span><span style="white-space:nowrap;font-family:Verdana;">%</span><span style="font-family:Verdana;"> or 0.05</span><span style="white-space:nowrap;font-family:Verdana;">%</span><span style="font-family:Verdana;"> v/v dosage for treatment. </span></span><span style="font-family:Verdana;">MFC power and current across an external resistor were measured daily for 10d. On d10, collected gases from anode compartment were measured for total gas volume and analyzed for gas composition on gas chromatography. Supplementation of saponin to MFC at 0.005</span><span style="white-space:nowrap;font-family:Verdana;">%</span><span style="font-family:Verdana;"> did not have any effects on electricity generation or biogas production and composition. Saponin at 0.05% dose reduced 10</span><span style="white-space:nowrap;font-family:Verdana;">%</span><span style="font-family:Verdana;"> of methane production and increased 40</span><span style="white-space:nowrap;font-family:Verdana;">%</span><span style="font-family:Verdana;"> of CO</span><sub><span style="font-family:Verdana;">2</span></sub><span style="font-family:Verdana;"> production and 6.4</span><span style="white-space:nowrap;font-family:Verdana;">%</span><span style="font-family:Verdana;"> of total gas production for 10d MFC operation. Voltage across resistor prior to treatment addition (d0) was 164.75 ± 9.07 mV. In control group, voltage across resistor did not change (P = 0.9153) with time course and mean was 167.8 ± 8.20 mV ranged from 157 to 174.5 mV during 10d operation. In 0.05</span><span style="white-space:nowrap;font-family:Verdana;">%</span><span style="font-family:Verdana;"> Saponin group, voltage across resistor increased (P <</span></span><span style="font-family:Verdana;"> 0</span><span style="font-family:""><span style="font-family:Verdana;">.0001) after d2 and mean was 187.3 ± 4.30 mV ranged between 161.5 and 204.0 mV and the 10d mean of voltage across resistor in 0.05</span><span style="white-space:nowrap;font-family:Verdana;">%</span><span style="font-family:Verdana;"> Saponin was greater (P <</span></span><span style="font-family:Verdana;"> 0</span><span style="font-family:""><span style="font-family:Verdana;">.0001) than in control group. 0.05</span><span style="white-space:nowrap;font-family:Verdana;">%</span><span style="font-family:Verdana;"> Saponin also had greater voltage across resistor at d5 (P = 0.0030) and d6 (P = 0.0246) than control. End point potential increased (P <</span></span><span style="font-family:Verdana;"> 0</span><span style="font-family:""><span style="font-family:Verdana;">.0001) in 0.05</span><span style="white-space:nowrap;font-family:Verdana;">%</span><span style="font-family:Verdana;"> Saponin after d2. 0.05</span><span style="white-space:nowrap;font-family:Verdana;">%</span><span style="font-family:Verdana;"> Saponin had greater (P < 0.05) end point potentials than control at d1, d4, d7, d10, and also 10d mean was greater (731.9 vs 606.5 mV;P <</span></span><span style="font-family:Verdana;"> 0</span><span style="font-family:""><span style="font-family:Verdana;">.0001) in 0.05</span><span style="white-space:nowrap;font-family:Verdana;">%</span><span style="font-family:Verdana;"> Saponin. Power density increased (P <</span></span><span style="font-family:Verdana;"> 0</span><span style="font-family:""><span style="font-family:Verdana;">.0001) after d2 in 0.05</span><span style="white-space:nowrap;font-family:Verdana;">%</span><span style="font-family:Verdana;"> Saponin. 0.05</span><span style="white-space:nowrap;font-family:Verdana;">%</span><span style="font-family:Verdana;"> Saponin MFCs had greater (P < 0.05) power density than control at d5 and d6, and also a greater (P <</span></span><span style="font-family:Verdana;"> 0</span><span style="font-family:Verdana;">.0001) overall mean of 10d operation. The current study provides strong background for potential use of saponin and saponin containing natural resources for methanogenesis inhibitor and cellulolysis enhancer in MFC and also cellulolysis reactors.
文摘This work proposed a simple and efficient approach for synthesis of durable and efficient non-precious metal oxygen reduction reaction(ORR) electro-catalysts in MFCs. The rod-like carbon nanotubes(CNTs)were formed on the Fe–N/SLG sheets after a carbonization process. The maximum power density of1210 ± 23 m W·m^(-2) obtained with Fe–N/SLG catalyst in an MFC was 10.7% higher than that of Pt/C catalyst(1080 ± 20 mW ·m^(-2)) under the same condition. The results of RDE test show that the ORR electron transfer number of Fe–N/SLG was 3.91 ± 0.02, which suggested that ORR catalysis proceeds through a four-electron pathway. The whole time of the synthesis of electro-catalysts is about 10 h, making the research take a solid step in the MFC expansion due to its low-cost, high efficiency and favorable electrochemical performance. Besides, we compared the electrochemical properties of catalysts using SLG, high conductivity graphene(HCG, a kind of multilayer graphene) and high activity graphene(HAG, a kind of GO) under the same conditions, providing a solution for optimal selection of cathode catalyst in MFCs.The morphology, crystalline structure, elemental composition and ORR activity of these three kinds of Fe–N/C catalysts were characterized. Their ORR activities were compared with commercial Pt/C catalyst.It demonstrates that this kind of Fe–N/SLG can be a type of promising highly efficient catalyst and could enhance ORR performance of MFCs.
文摘The focus of microbial fuel cell research in recent years has been on the development of materials,microbes,and transfer of charges in the system,resulting in a substantial improvement in current density and improved power generation.The cathode is generally recognized as the limiting factor due to its high-distance proton transfer,slow oxygen reduction reaction(ORR),and expensive materials.The heterogeneous reaction determines power gen-eration in MFC.This comprehensive review describes-recent advancements in the development of cathode mate-rials and catalysts associated with ORR.The recent studies indicated the utilization of different metal oxides,the ferrite-based catalyst to overcome this bottleneck.These studies conclude that some cathode materials,in parti-cular,graphene-based conductive polymer composites with non-precious metal catalysts provide substantial ben-efits for sustainable development in the field of MFCs.Furthermore,it also highlights the potentiality to replace the conventional platinum air cathode for the large-scale production of the next generation of MFCs.It was evi-dent from the experiments that cathode catalyst needs to be blended with conductive carbon materials to make cathode conductive and efficient for ORR.This review discusses various antifouling strategies for cathode biofoul-ing and its effect on the MFC performance.Moreover,it also depicts cost estimations of various catalysts essential for further scale-up of MFC technology.
文摘Microbial fuel cells(MFCs)are an attractive innovation at the nexus of energy and water security for the future.MFC utilizes electrochemically active microorganisms to oxidize biodegradable substrates and generate bioelectricity in a single step.The material of the anode plays a vital role in increasing the MFC’s power output.The anode in MFC can be upgraded using nanomaterials providing benefits of exceptional physicochemical properties.The nanomaterials in anode gives a high surface area,improved electron transfer promotes electroactive biofilm.Enhanced power output in terms of Direct current(DC)can be obtained as the consequence of improved microbe-electrode interaction.However,several limitations like complex synthesis and degeneration of property do exist in the development of nanomaterial-based anode.The present review discusses different renewable nanomaterial applied in the anode to recover bioelectricity in MFC.Carbon nanomaterials have emerged in the past decade as promising materials for anode construction.Composite materials have also demonstrated the capacity to become potential anode materials of choice.Application of a few transition metal oxides have been explored for efficient extracellular electron transport(EET)from microbes to the anode.
基金supported jointly by Natural Science Foundation of China(51878309)National Key Research and Development Program of China(2018YFC1900105).
文摘Microbial fuel cells(MFCs),as a sustainable and promising technology to solve both environmental pollution and energy shortage,have captured tremendous attention.The conversion efficiency of chemical energy contained in organic waste or wastewater to electricity via microbial metabolism strongly depends on the performance of each functional unit,including the anode,cathode and separator/membrane used in MFCs.Therefore,significant attention has been paid toward developing advanced functional materials to enhance the performance of each unit or provide new featured functions.This review paper provides a comprehensive review on recent achievements and advances in the modification and development of functional materials for MFC systems,including 1)the development of functional anode materials for enhanced microbial compatibilities as well as electron transfer capabilities,2)the development of cost-effective separators/membranes such as ion exchange membrane,porous membrane,polymer electrolyte membrane and composite membrane,and 3)the development of functional cathode catalysts to decrease the over-potential and enhance the electrocatalytic efficiency for oxygen reduction reaction in order to substitute the common costly Pt catalyst.The challenges and outlooks of functional materials for MFC applications are also discussed.
基金Sponsored by the National Natural Science Key Foundation of China(Grant No.51206036)the Fundamental Research Funds for the Central Universities(Grant No.HIT.NSRIF.201192)+1 种基金State Key Laboratory of Urban Water Resource and EnvironmentHarbin Institute of Technology(Grant No.2013DX04)
文摘This paper compared the degradation efficiency of sludge organic matters and electric-production by two typical microbial fuel cells——dual-chamber microbial fuel cell(DMFC)and single chamber air cathode microbial fuel cell(SAMFC),and the variations of sludge protein,polysaccharide and ammonia nitrogen within the systems were also investigated.The results showed that the concentration of sludge soluble chemical oxygen demand,protein and carbohydrate of DMFC are higher than these of SAMFC during the systems operation,while DMFC can achieve a better ammonia nitrogen removal than SAMFC.Under the same operation condition,the stable voltage output of DMFC and SAMFC is 0.61 V and 0.37 V;the maximum power density of DMFC and SAMFC is 2.79 W/m3and 1.25 W/m3;TCOD removal efficiency of DMFC and SAMFC is 34.14%and 28.63%for 12 d,respectively.Meanwhile,DMFC has a higher coulomb efficiency than SAMFC,but both are less than5%.The results showed that DMFC present a better performance on sludge degradation and electric-production.
文摘Microbial fuel cell (MFC) is one of the clean and sustainable energy technologies, often referred to as renewable energy, and directly chemical energy contained in organic matter into electrical energy by using the catalytic activity of microorganisms. Cellulosic biomass is a particularly attractive renewable resource for its abundant supply at low cost and its neutral carbon balance. However, methanogenesis had been negatively linked to anaerobic cellulosic power generation in MFCs. Ginseng root is a saponin-rich plant material and red ginseng marc (RGM) has not been reused as a high-value resource for industry although its residue contained both electron donors and saponin, the potential power generation enhancers for MFC. In this study, RGM was supplemented into MFC to evaluate its effects on methanogenesis and power generation. Two-chamber H-type MFCs were established using rumen fluid as anolyte to ferment cellulose at 2% (w/v). RGM, the residue from the steam and press process for red ginseng beverage preparation, was freeze-dried and ground to pass 0.5 mm sieve and added to the anode of MFC at 1% (w/v;Exp. 1) or 0.1% (Exp. 2) dose for treatment. Open circuit voltage, voltage and current across an external resistor were measured daily for 10d. On d10 of operation, collected biogases were measured for total gas production and analyzed for its components. In Exp. 1, power density was between 44.0 and 97.2 with an average of 83.8 mW/m<sup>2</sup> in 1% RGM MFCs and was between 45.2 and 76.3 with an average of 61.5 mW/m<sup>2</sup> in control. In Exp. 2, power density was between 44.8 and 75.6 with an average of 60.9 mW/m<sup>2</sup> in 0.1% RGM MFCs and was between 45.1 and 54.1 with an average of 49.7 mW/m<sup>2</sup> in control. Total gas production for 10d was 563 and 523 mL for RGM and control, respectively, in Exp 1, and was 546 and 477 mL for RGM and control, respectively, in Exp 2. Methane took up 58.6 and 67.9% of total gas for RGM and control, respectively, in Exp 1, and 59.1 and 67.3% of total gas for RGM and control, respectively, in Exp 2. Both greater (P < 0.05) power generation less (P < 0.05) methane proportion in RGM MFCs in both Exp. 1 and 2 strongly supports the potential use of red ginseng marc as MFC supplements.
基金supported by the National Natural Science Foundation of China(No.42077284)the Natural Science Foundation of Fujian Province,China(No.2020J02015)the Fund for Outstanding Young Scientific Talent Cultivation Program of Fujian Agriculture and Forestry University of China(No.XJQ201906).
文摘Methane has been demonstrated to be a feasible substrate for electricity generation in microbial fuel cells(MFCs)and denitrifying anaerobic methane oxidation(DAMO).However,these two processes were evaluated separately in previous studies and it has remained unknown whether methane is able to simultaneously drive these processes.Here we investigated the co-occurrence and performance of these two processes in the anodic chamber of MFCs.The results showed that methane successfully fueled both electrogenesis and denitrification.Importantly,the maximum nitrate removal rate was significantly enhanced from(1.4±0.8)to(18.4±1.2)mg N/(L·day)by an electrogenic process.In the presence of DAMO,the MFCs achieved a maximum voltage of 610 mV and a maximum power density of 143±12 mW/m^(2).Electrochemical analyses demonstrated that some redox substances(e.g.riboflavin)were likely involved in electrogenesis and also in the denitrification process.High-throughput sequencing indicated that the methanogen Methanobacterium,a close relative of Methanobacterium espanolae,catalyzed methane oxidation and cooperated with both exoelectrogens and denitrifiers(e.g.,Azoarcus).This work provides an effective strategy for improving DAMO in methane-powered MFCs,and suggests that methanogens and denitrifiers may jointly be able to provide an alternative to archaeal DAMO for methane-dependent denitrification.
基金This research was supported by the EU Horizon 2020 project GREENER(Grant Agreement No 826312).The authors wish to thank:Jakub Dziegielowski and Bongkyu Kim,from the University of Bath,for their suggestions and help on assembling and setting-up the SMFCs,Anna Salvian and Simone Krings,from the University of Surrey,for their assistance in DNA extraction.
文摘Increasing energy demands and environmental pollution concerns press for sustainable and environmentally friendly technologies.Soil microbial fuel cell(SMFC)technology has great potential for carbon-neutral bioenergy generation and self-powered electrochemical bioremediation.In this study,an in-depth assessment on the effect of several carbon-based cathode materials on the electrochemical performance of SMFCs is provided for the first time.An innovative carbon nanofibers electrode doped with Fe(CNFFe)is used as cathode material in membrane-less SMFCs,and the performance of the resulting device is compared with SMFCs implementing either Pt-doped carbon cloth(PtC),carbon cloth,or graphite felt(GF)as the cathode.Electrochemical analyses are integrated with microbial analyses to assess the impact on both electrogenesis and microbial composition of the anodic and cathodic biofilm.The results show that CNFFe and PtC generate very stable performances,with a peak power density(with respect to the cathode geometric area)of 25.5 and 30.4 mW m^(−2),respectively.The best electrochemical performance was obtained with GF,with a peak power density of 87.3 mW m^(−2).Taxonomic profiling of the microbial communities revealed differences between anodic and cathodic communities.The anodes were predominantly enriched with Geobacter and Pseudomonas species,while cathodic communities were dominated by hydrogen-producing and hydrogenotrophic bacteria,indicating H_(2)cycling as a possible electron transfer mechanism.The presence of nitrate-reducing bacteria,combined with the results of cyclic voltammograms,suggests microbial nitrate reduction occurred on GF cathodes.The results of this study can contribute to the development of effective SMFC design strategies for field implementation.
基金This work was supported by the Ministry of Higher Education Malaysia via Fundamental Research Grant Scheme(FRGS)[FRGS/1/2022/STG01/UM/03/2][FP064-2022]Ministry of Higher Education Malaysia under the Higher Institution Centre of Excellence(HICoE)Programme[IOES-2014F]+1 种基金UM Innovate Fund[PPSI-2020-HICOE-03]the Research University Grant,Universiti Malaya[RU003-2022].
文摘Despite more than a decade of study,there are still significant obstacles to overcome before graphene can be successfully produced on a large scale for commercial use.Chemical oxidation of graphite to produce graphene oxide(GO),followed by a subsequent reduction process to synthesize reduced graphene oxide(rGO),is considered the most practical method for mass production.Microorganisms,which are abundant in nature and inexpensive,are one of the potential green reductants for rGO synthesis.However,there is no recent review discussing the reported microbial reduction of GO in detail.To address this,we present a comprehensive review on the reduction of GO by a range of microorganisms and compared their efficacies and reaction conditions.Also,presented were the mechanisms by which microorganisms reduce GO.We also reviewed the recent advancements in using microbially reduced GO as the anode and cathode material in the microbial fuel cell(MFC)and algal biophotovoltaics(BPV),as well as the challenges and future directions in microbial fuel cell research.
基金supported by the National Natural Science Foundation of China(No.51308530)the Natural Science Foundation of Hubei Province,China(No.2015CFB558)+1 种基金the National Key R&D Program of China(No.2016YFC0500403-03)the Major Projects of Technical Innovation in Hubei Province(No.2016ACA169)
文摘To find suitable wetland plants for constructed wetland-microbial fuel cells(CW-MFCs),four commonly used wetland plants, including Canna indica, Cyperus alternifolius L., Acorus calamus, and Arundo donax, were investigated for their electrogenic performance and physiological changes during non-growing seasons. The maximum power output of12.82 mW/m^2 was achieved in the A. donax CW-MFC only when root exudates were being released. The results also showed that use of an additional carbon source could remarkably improve the performance of electricity generation in the C. indica and A. donax CW-MFCs at relatively low temperatures(2–15°C). However, A. calamus withered before the end of the experiment, whereas the other three plants survived the winter safely, although their relative growth rate values and the maximum quantum yield of PSII(Fv/Fm) significantly declined, and free proline and malondialdehyde significantly accumulated in their leaves.On the basis of correlation analysis, temperature had a greater effect on plant physiology than voltage. The results offer a valuable reference for plant selection for CW-MFCs.
基金the National Key Research and Development Program of China(No.2021YFA0910400)the National Natural Science Foundation of China(Nos.21605110 and 21972102)+1 种基金Natural Science Research Foundation of Jiangsu Higher Education Institutions(Nos.19KJB150038 and 21KJB180018)Natural Science Foundation of Suzhou University of Science and Technology(Nos.XKQ2018014 and XKZ2019011)。
文摘Pore structure plays critical roles in electrode kinetics but very challenging to tailor porous nanowires with rationally distributed pore sizes in a bioelectrochemical system.Herein a hierarchically porous nanowires-material is delicately tuned for an optimal pore structure by adjusting the weight percentage of SiO_(2)-hard template in an electrospinning precursor solution.The asprepared optimal electrospinning nanowires further used as an anode of microbial fuel cells(MFCs),delivering a maximum output power density of 1,407.42 mW·m^(−2)with 4.24 and 10 times higher than that of the non-porous fiber and carbon cloth anode,respectively.The great enhancement is attributed to the rational pore structure which offers the largest surface area while the rich-mesopores well match with the size of electron mediators for a high density of catalytic centers.This work provides thoughtful insights to design of hierarchical porous electrode for high-performance MFCs and other bioelectrochemical system devices.
基金This article was funded by National Natural Science Foundation of China(Grant nos.51672143,21805148,22075157,52102271).
文摘Developing low-cost,efficient oxygen reduction reaction(ORR)catalysts to replace Pt-based materials is urgently required for the application of Zn-air batteries(ZABs)and microbial fuel cells(MFCs).In this work,meso-microporous carbon fibers with tunable defect density were synthesized by carrageenan fibers.A highly defective carbon fiber(HDCFs)was produced which exhibited an outstanding ORR catalytic activity,reaching to the half-wave potential of 0.841 and 0.44 V in alkaline and neutral electrolytes,respectively.These HDCFs can also act as highly efficient air cathodes for ZABs(delivered potential of 0.69 V and power density of 220 mW cm^(–2) at 300 mA cm^(–2))and MFCs(high power density of 69.7 mW cm^(–2)).Simulation by the density functional theory indicated that a high density of defections in a carbon based framework can remarkably modulate the electrical properties.For instance the charge entrapments in the carbon active sites may reduce the energy barrier of ORR.
基金supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT) (2021R1A2B5B01002656)。
文摘Microbial fuel cell(MFC) is an advanced bioelectrochemical technique that can utilize biomass materials in the process of simultaneously generating electricity and biodegrading or bio transforming toxic pollutants from wastewater. The overall performance of the system is largely dependent on the efficiency of the anode electrode to enhance electron transportation. Furthermore, the anode electrode has a significant impact on the overall cost of MFC setup. Hence, the need to explore research focused towards developing cost-effective material as anode in MFC. This material must also have favourable properties for electron transportation. Graphene oxide(GO) derivatives and its modification with nanomaterials have been identified as a viable anode material. Herein, we discussed an economically effective strategy for the synthesis of graphene derivatives from waste biomass materials and its subsequent fabrication into anode electrode for MFC applications. This review article offers a promising approach towards replacing commercial graphene materials with biomass-derived graphene derivatives in a view to achieve a sustainable and commercialized MFC.
