The increase in release of toxic heavy metals into natural water attracts much attention due to its devastating effect on ecology and human health.The design and implementation of green electrode materials is pivotal ...The increase in release of toxic heavy metals into natural water attracts much attention due to its devastating effect on ecology and human health.The design and implementation of green electrode materials is pivotal for improving the electrochemical performance of in situ heavy metal monitoring.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
Over half of century,sanitary landfill was and is still the most economical treatment strategy for solid waste disposal,but the environmental risks associated with the leachate have brought attention of scientists for...Over half of century,sanitary landfill was and is still the most economical treatment strategy for solid waste disposal,but the environmental risks associated with the leachate have brought attention of scientists for its proper treatment to avoid surface and ground water deterioration.Most of the treatment technologies are energy-negative and cost intensive processes,which are unable to meet current environmental regulations.There are continuous demands of alternatives concomitant with positive energy and high effluent quality.Microbial fuel cells(MFCs)were launched in the last two decades as a potential treatment technology with bioelectricity generation accompanied with simultaneous carbon and nutrient removal.This study reviews capability and mechanisms of carbon,nitrogen and phosphorous removal from landfill leachate through MFC technology,as well as summarizes and discusses the recent advances of standalone and hybrid MFCs performances in landfill leachate(LFL)treatment.Recent improvements and synergetic effect of hybrid MFC technology upon the increasing of power densities,organic and nutrient removal,and future challenges were discussed in details.展开更多
Many studies have investigated the effects of different pretreatments on the performance of anaerobic digestion of sludge.However,the detailed changes of dissolved organic nitrogen,particularly the release behavior of...Many studies have investigated the effects of different pretreatments on the performance of anaerobic digestion of sludge.However,the detailed changes of dissolved organic nitrogen,particularly the release behavior of proteins and the byproducts of protein hydrolysis-amino acids,are rarely known during anaerobic digestion of sludge by different pretreatments.Here we quantified the changes of three types of proteins and 17 types of amino acids in sludge samples solubilized by ultrasonic,thermal,and acid/alkaline pretreatments and their transformation during anaerobic digestion of sludge.Tryptophan protein,aromatic protein I,aromatic protein II,and cysteine were identified as the key dissolved organic nitrogen responsible for methane production during anaerobic digestion of sludge,regardless of the different pretreatment methods.Different from the depletion of other amino acids,cysteine was resistant to degradation after an incubation period of 30 days in all sludge samples.Meanwhile,the“cysteine and methionine metabolism(K00270)”was absent in all sludge samples by identifying 6755 Kyoto Encyclopedia of Genes and Genomes assignments of genes hits.Cysteine contributed to the generation of methane and the degradation of acetic,propionic,and n-butyric acids through decreasing oxidation-reduction potential and enhancing biomass activity.This study provided an alternative strategy to enhance anaerobic digestion of sludge through in situ production of cysteine.展开更多
This study compared effects of three different valent iron(Fe^(0),Fe(II)and Fe(III))on enhanced anaerobic sludge digestion,focusing on the changes of oxidation reduction potential(ORP),dissolved organic nitrogen(DON),...This study compared effects of three different valent iron(Fe^(0),Fe(II)and Fe(III))on enhanced anaerobic sludge digestion,focusing on the changes of oxidation reduction potential(ORP),dissolved organic nitrogen(DON),and microbial community.Under the same iron dose in range of 0−160 mg/L after an incubation period of 30 days(d),the maximum methane production rate of sludge samples dosed with respective Fe^(0),Fe(II)and Fe(III)at the same concentration showed indiscernible differences at each iron dose,regardless of the different iron valence.Moreover,their behavior in changes of ORP,DON and microbial community was different:(1)the addition of Fe^(0) made the ORP of sludge more negative,and the addition of Fe(II)and Fe(III)made the ORP of sludge less negative.However,whether being more or less negative,the changes of ORP may show unobservable effects on methane yield when it ranged from−278.71 to−379.80 mV;(2)the degradation of dissolved organic nitrogen,particularly proteins,was less efficient in sludge samples dosed with Fe^(0) compared with those dosed with Fe(II)and Fe(III)after an incubation period of 30 d.At the same dose of 160 mg/L iron,more cysteine was noted in sludge samples dosed with Fe(II)(30.74 mg/L)and Fe(III)(27.92 mg/L)compared with that dosed with Fe^(0)(21.75 mg/L);(3)Fe^(0) particularly promoted the enrichment of Geobacter,and it was 6 times higher than those in sludge samples dosed with Fe(II)and Fe(III)at the same dose of 160 mg/L iron.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
基金The authors would like acknowledge the financial supports from National Pro-gram on Key Basic Research of China(973 Program,2015CB258400)the National Thousand Young Talents Program,Natural Science Foundation of China(51508213,51608217,and 21607046)+1 种基金Innovative and Interdisciplinary Team at HUST(0118261077)the Fundamental Research Funds for Central Universi-ties(2017KFYXJJ217).
文摘The increase in release of toxic heavy metals into natural water attracts much attention due to its devastating effect on ecology and human health.The design and implementation of green electrode materials is pivotal for improving the electrochemical performance of in situ heavy metal monitoring.
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supported by the National Key Research and Development Program of China (No. 2018YFD1100604)the China Scholarship Council grant (CSC No. 2018GBJ008465)。
文摘Over half of century,sanitary landfill was and is still the most economical treatment strategy for solid waste disposal,but the environmental risks associated with the leachate have brought attention of scientists for its proper treatment to avoid surface and ground water deterioration.Most of the treatment technologies are energy-negative and cost intensive processes,which are unable to meet current environmental regulations.There are continuous demands of alternatives concomitant with positive energy and high effluent quality.Microbial fuel cells(MFCs)were launched in the last two decades as a potential treatment technology with bioelectricity generation accompanied with simultaneous carbon and nutrient removal.This study reviews capability and mechanisms of carbon,nitrogen and phosphorous removal from landfill leachate through MFC technology,as well as summarizes and discusses the recent advances of standalone and hybrid MFCs performances in landfill leachate(LFL)treatment.Recent improvements and synergetic effect of hybrid MFC technology upon the increasing of power densities,organic and nutrient removal,and future challenges were discussed in details.
基金The research was supported by the National Natural Science Foundation of China(Grant Nos.51708239 and U1901216)Natural Science Foundation of Hubei Province(No.2020CFA042)+1 种基金Applied Basic Research Program of Wuhan(No.2020020601012277)Additionally,we would also like to thank the Analytical and Testing Center of Huazhong University of Science and Technology for providing experimental measurements.
文摘Many studies have investigated the effects of different pretreatments on the performance of anaerobic digestion of sludge.However,the detailed changes of dissolved organic nitrogen,particularly the release behavior of proteins and the byproducts of protein hydrolysis-amino acids,are rarely known during anaerobic digestion of sludge by different pretreatments.Here we quantified the changes of three types of proteins and 17 types of amino acids in sludge samples solubilized by ultrasonic,thermal,and acid/alkaline pretreatments and their transformation during anaerobic digestion of sludge.Tryptophan protein,aromatic protein I,aromatic protein II,and cysteine were identified as the key dissolved organic nitrogen responsible for methane production during anaerobic digestion of sludge,regardless of the different pretreatment methods.Different from the depletion of other amino acids,cysteine was resistant to degradation after an incubation period of 30 days in all sludge samples.Meanwhile,the“cysteine and methionine metabolism(K00270)”was absent in all sludge samples by identifying 6755 Kyoto Encyclopedia of Genes and Genomes assignments of genes hits.Cysteine contributed to the generation of methane and the degradation of acetic,propionic,and n-butyric acids through decreasing oxidation-reduction potential and enhancing biomass activity.This study provided an alternative strategy to enhance anaerobic digestion of sludge through in situ production of cysteine.
基金funded by the National Natural Science Foundation of China(Grant Nos.52170133,U1901216,51708239)the Natural Science Foundation of Hubei Province(No.2020CFA042)Applied Basic Research Program of Wuhan(No.2020020601012277),and Program for HUST Academic Frontier Youth Team.
文摘This study compared effects of three different valent iron(Fe^(0),Fe(II)and Fe(III))on enhanced anaerobic sludge digestion,focusing on the changes of oxidation reduction potential(ORP),dissolved organic nitrogen(DON),and microbial community.Under the same iron dose in range of 0−160 mg/L after an incubation period of 30 days(d),the maximum methane production rate of sludge samples dosed with respective Fe^(0),Fe(II)and Fe(III)at the same concentration showed indiscernible differences at each iron dose,regardless of the different iron valence.Moreover,their behavior in changes of ORP,DON and microbial community was different:(1)the addition of Fe^(0) made the ORP of sludge more negative,and the addition of Fe(II)and Fe(III)made the ORP of sludge less negative.However,whether being more or less negative,the changes of ORP may show unobservable effects on methane yield when it ranged from−278.71 to−379.80 mV;(2)the degradation of dissolved organic nitrogen,particularly proteins,was less efficient in sludge samples dosed with Fe^(0) compared with those dosed with Fe(II)and Fe(III)after an incubation period of 30 d.At the same dose of 160 mg/L iron,more cysteine was noted in sludge samples dosed with Fe(II)(30.74 mg/L)and Fe(III)(27.92 mg/L)compared with that dosed with Fe^(0)(21.75 mg/L);(3)Fe^(0) particularly promoted the enrichment of Geobacter,and it was 6 times higher than those in sludge samples dosed with Fe(II)and Fe(III)at the same dose of 160 mg/L iron.
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.