Showing papers on "Microbial electrolysis cell published in 2013"
TL;DR: In this paper, the authors summarized the efforts of different research groups to develop different types of efficient and low-cost cathodes or cathode catalysts for hydrogen generation, including stainless steel, Ni alloys Pd nanoparticle decorated cathode.
279 citations
TL;DR: A review of the recent advances on microbial fuel cells (MFCs) designs and operations is given in this paper. But, the authors do not provide a detailed analysis of the current state of the art.
Abstract: Bioenergy is a renewable energy that plays an indispensable role in meeting today's ever increasing energy needs. Unlike biofuels, microbial fuel cells (MFCs) convert energy harvested from redox reactions directly into bioelectricity. MFCs can utilize low-grade organic carbons (fuels) in waste streams. The oxidation of the fuel molecules requires biofilm catalysis. In recent years, MFCs have also been used in the electrolysis mode to produce bioproducts in laboratory tests. MFCs research has intensified in the past decade and the maximum MFCs power density output has been increased greatly and many types of waste streams have been tested. However, new breakthroughs are needed for MFCs to be practical in wastewater treatment and power generation beyond powering small sensor devices. To reduce capital and operational costs, simple and robust membrane-less MFCs reactors are desired, but these reactors require highly efficient biofilms. Newly discovered conductive cell aggregates, improved electron transport through hyperpilation via mutation or genetic recombination and other advances in biofilm engineering present opportunities. This review is an update on the recent advances on MFCs designs and operations. © 2012 Society of Chemical Industry
212 citations
TL;DR: A ‘proof of concept’ has been made, showing that this technology is capable of energy capture as hydrogen gas from low strength domestic wastewaters at ambient temperatures.
Abstract: Addressing the need to recover energy from the treatment of domestic wastewater, a 120-L microbial electrolysis cell was operated on site in Northern England, using raw domestic wastewater to produce virtually pure hydrogen gas (100 ± 6.4 %) for a period of over 3 months. The volumetric loading rate was 0.14 kg of chemical oxygen demand (COD) per cubic metre per day, just below the typical loading rates for activated sludge of 0.2-2 kg COD m(-3) day(-1), at an energetic cost of 2.3 kJ/g COD, which is below the values for activated sludge 2.5-7.2 kJ/g COD. The reactor produced an equivalent of 0.015 LH(2)L(-1) day(-1), and recovered around 70 % of the electrical energy input with a coulombic efficiency of 55 %. Although the reactor did not reach the breakeven point of 100 % electrical energy recovery and COD removal was limited, improved hydrogen capture and reactor design could increase the performance levels substantially. Importantly, for the first time, a 'proof of concept' has been made, showing that this technology is capable of energy capture as hydrogen gas from low strength domestic wastewaters at ambient temperatures.
206 citations
TL;DR: In this article, the principles of photofermentation and dark fermentation by reusing various wastes as substrates are reviewed, as well as future prospects of hydrogen usage and hydrogen economy are also discussed.
Abstract: Hydrogen has been introduced as a potential replacement for energy resource due to the depletion of fossil fuel and raising awareness about global climate change and health problems caused by the combustion of fossil fuel. One of the attractive options to produce hydrogen is through microbial fermentation which can be classified into biophotolysis, dark fermentation, photofermentation, and microbial electrolysis cell. Among these, dark fermentation and photofermentation technologies were processes that were being studied widely. One of the reasons is that organic waste could be reused as a substrate during biohydrogen production. Although the current biohydrogen yields are low, it is expected that with improvements technology and genetic engineering, the amount of generated biohydrogen could be enhanced tremendously, and provide a sustainable way of reutilizing waste as a substrate. Thus, this paper reviews the principles of photofermentation and dark fermentation by reusing various wastes as substrates. The resulting performances, limitations, as well as future prospects of hydrogen usage and hydrogen economy are also discussed. © 2013 Society of Chemical Industry and John Wiley & Sons, Ltd
181 citations
TL;DR: The MEC can be used for the treatment of low-strength wastewater, with good energy efficiency and low sludge production, and low biomass growth was observed at the anode and ammonium was transferred through the cationic membrane and concentrated at the cathode.
141 citations
TL;DR: A bioelectrochemical reactor was investigated for simultaneous hydrogen production and ammonium recovery from reject water, which is an ammonium-rich side-stream produced from sludge treatment processes at wastewater treatment plants.
125 citations
TL;DR: This study demonstrates microbial electrolysis cell (MEC) scale-up from a 50mL to a 10L cell by optimizing the hydraulic retention time (HRT) and individually controlling the applied voltages of three anodic compartments with a real-time optimization algorithm.
105 citations
TL;DR: Pyrosequencing and denaturing gradient gel electrophoresis analysis revealed that the dominant bacteria and archaea communities were richer and more abundant in the anode biofilm and R1 and the reduced Fe(II) combined with electric field resulted more extracellular polymeric substances (EPS) production.
101 citations
TL;DR: The reduction of sulphate led to sulphide production, which was entrapped in the ionic form thanks to the high biocathode pH (i.e. pH of 10) obtained during the process.
89 citations
TL;DR: Feasibility of integrating Microbial electrolysis cell (MEC) process with dark-fermentation process for additional hydrogen recovery as well as substrate degradation was demonstrated in the present study.
79 citations
TL;DR: In this article, a microbial electrolysis cell was powered by a capacitor based energy storage circuit using energy from a microbial fuel cell (MFC) to increase MEC hydrogen production rates compared to that possible by the MFC alone.
TL;DR: Hydrogen production was limited by the reduced amounts of organic matter fed into the reactor, the poor performance of the cathode, and COD consuming by non electrogenic microorganisms.
TL;DR: In this paper, a proton exchange membrane is used to separate the anode chamber and the cathode chamber to overcome the thermodynamic barrier for hydrogen production from acetate without the aid of power supply.
TL;DR: An organic loading rate (OLR) threshold is identified that makes the use of MECs for dWW treatment feasible in terms of energy consumption and COD removal efficiency and an OLR threshold that justifies the operation of two M ECs in series to provide the required degree of COD Removal.
TL;DR: In this paper, the Coulombic efficiency was used to directly calculate energy consumption relative to wastewater treatment in terms of COD removal, and that the average current, not maximum current, was a better metric to evaluate the rate of the bioelectrochemical reactions.
TL;DR: Pyrosequencing revealed that dominant populations in anode biofilm and R1 were more diverse and abundant than the common anaerobic reactor (R2), and there was a significant distinction among anode film, R1 and R2 in microbial community structure.
TL;DR: In this paper, the authors provided a theoretical approach to understand the fate of hydrogen in microbial electrolysis cells (MECs) through electron equivalent balances, and validated it with a long-term operated single-chamber membrane-less MEC.
TL;DR: This study demonstrates for the first time production of high concentrations of H2O2 production from real municipal wastewater, and suggests this concentration could poTENTially be useful for membrane cleaning at membrane bioreactor wastewater treatment plants.
Abstract: Bioelectrochemical systems can be used to energy-efficiently produce hydrogen peroxide (H2O2) from wastewater. Organic compounds in the wastewater are oxidized by microorganisms using the anode as electron acceptor. H2O2 is produced by reduction of oxygen on the cathode. In this study, we demonstrate for the first time production of high concentrations of H2O2 production from real municipal wastewater. A concentration of 2.26 g/L H2O2 was produced in 9 h at 8.3 kWh/kgH2O2. This concentration could poTENTially be useful for membrane cleaning at membrane bioreactor wastewater treatment plants. With an acetate-containing nutrient medium as anode feed, a H2O2 concentration of 9.67 g/L was produced in 21 h at an energy cost of 3.0 kWh/kgH2O2. The bioelectrochemical reactor used in this study suffered from a high internal resistance, most likely caused by calcium carbonate deposits on the cathode-facing side of the cation exchange membrane separating the anode and cathode compartments.
TL;DR: The molecular-phylogenetic analysis of the bacteria on the biocathode indicated that the community was comprised of six phyla, in which Firmicutes was the most populated phylum (77% of the clones in the 16S rRNA library).
TL;DR: In this article, an anaerobic baffled reactor (ABR) coupled with a microbial electrolysis cell (MEC) has been operated to strengthen the hydrogen production and achieve high acetic acid accumulation of effluent.
TL;DR: In this paper, the authors studied MEC performance at steady-state conditions in continuous mode and analyzed the performance of MEC in terms of chemical efficiency, and they found that MECs perform better at high buffer and electrolyte concentrations.
TL;DR: In this paper, a dual-chamber microbial electrolysis cell (MEC) was designed for maintaining high concentration of anode-respiring bacteria per membrane surface area, which generated 8.3 A m−2 of membrane area of which 57% was produced by endogenous decay of ARB under substrate deficient conditions.
Abstract: We designed a dual-chamber microbial electrolysis cell (MEC) which provided a large anode surface area against membrane surface area, but kept a short distance between the anode and the cathode. Current density ranged from 8.3 to 11 A m−2 of membrane surface area for chemical oxygen demand (COD) loading rate 0.3–6.3 kg COD/m3 d. Hydrogen recovery (from coulombs to H2) was as high as 93 ± 25% in the MEC, and hydrogen production rate ranged from 66.4 ± 18.0 to 137.2 ± 14.4 L H2/m2 d at an applied voltage of ∼1.2 V. As a result, H2 production costs were computed at $0.17–0.25/m3 H2 ($1.7–2.6/kg H2 at 25 °C and 1 atm) in the MEC using stainless steel mesh as the cathode. The MEC designed for maintaining high concentration of anode-respiring bacteria per membrane surface area generated 8.3 A m−2 of membrane area of which 57% was produced by endogenous decay of ARB under substrate deficient conditions. Soluble microbial products (SMP) were quantified for acetate-utilizing ARB in the MEC, and SMP fraction of influent COD was 23%. We separately measured biomass-associated products and utilization-associated products of SMP experimentally, which were 286 ± 100 mg L−1 and 59 ± 30 mg COD L−1, respectively.
TL;DR: In this paper, the authors explored different extra applied voltages (0.6 − 1.2 − 2.2 ) for different applications of synchronous double-frequency (SDF) and alkaline coupling with anaerobic fermentation.
01 Jan 2013
TL;DR: In this paper, an attempt was made to bring out all the existing applications of MFC into one platform to make a comprehensive understanding on the inherent potential of microbial metabolism, when the designated electron acceptor is present.
Abstract: The energy gain in microbes is driven by oxidizing an electron donor and reducing an electron acceptor. Variation in the electron acceptor conditions creates a feasibility to harness energy. In order to support the microbial respiration, electrons will transfer to the exocellular medium toward the available electron acceptor, especially in the absence of oxygen. The microbes can use a wide range of electron acceptors such as metals, nutrients, minerals, etc., including solid electrodes. When the microbes use the solid electrode as electron acceptors, the setup is called microbial fuel cell (MFC) and the electrons can be harvested and used for different applications. MFC can be defined as a microbially catalyzed electrochemical system which can facilitate the direct conversion of substrate to electricity through a cascade of redox reactions, especially in the absence of oxygen. Linking the microbial metabolism to anode and then transmitting the electrons to cathode generates a net electrical power from the degradation of available electron donor. This concept of MFC operation has expanded considerable interest in the recent research due to its application in the energy recovery from wastewater. Microbes in MFC can also use variety of organic or inorganic electron donors as well as acceptors to produce a surfeit of desirable biofuels or biochemicals which is termed as microbial electrosynthesis. Apart from the electrogensis, the applications of MFC are widespread in different fields including waste/wastewater remediation, toxic pollutants/xenobiotics removal, recovery of commercially viable products, sequestration of CO2, harvesting the energy stored in marine sediments, desalination, etc. In this chapter, an attempt was made to bring out all the existing applications of MFC into one platform to make a comprehensive understanding on the inherent potential of microbial metabolism, when the designated electron acceptor is present.
TL;DR: In this article, the influence of applied voltage and hydraulic retention time on hydrogen and methane production and the removal rate for chemical oxygen demand (COD) was studied in a membrane-less microbial electrolysis cell with a Ni-based cathode.
Abstract: The influence of the applied voltage (Vapp) and the hydraulic retention time (HRT) on hydrogen and methane production and the removal rate for chemical oxygen demand (COD) was studied in a membrane-less microbial electrolysis cell with a Ni-based cathode. When a synthetic effluent from a dark-fermentation process was fed continuously into the anodic chamber, an increase in both the Vapp (from 0.6 to 1.0 V) and HRT (from 8 to 12 h) increased the hydrogen production rate from 0.18 to 1.42 L LA−1 d−1 (liters per liter of anode per day) and the COD elimination rate from 46 to 94%. The influences of Vapp and HRT on hydrogen production and the COD removal rate were found to be interdependent. Whereas acetic and butyric acids were easily degraded, propionic acid exhibited pseudo-recalcitrant behavior. © 2012 American Institute of Chemical Engineers Environ Prog, 32: 263-268, 2013
TL;DR: In this paper, two microbial electrolysis cells (MECs) were operated at different temperature settings with acetate as a carbon source, and the results of volatile suspended solids analysis indicated that biomass concentration continued to drop at all temperatures, but the drop was the lowest at 30°C.
TL;DR: MFC operating principles are analysed using bioenergetics and bioelectrochemistry to improve the MFC performance and recent advances in the production of various biomaterials were investigated.
Abstract: Today's global energy crisis requires a multifaceted solution. Bioenergy is an important part of the solution. The microbial fuel cell (MFC) technology stands out as an attractive potential technology in bioenergy. MFCs can convert energy stored in organic matter directly into bioelectricity. MFCs can also be operated in the electrolysis mode as microbial electrolysis cells to produce bioproducts such as hydrogen and ethanol. Various wastewaters containing low-grade organic carbons that are otherwise unutilized can be used as feed streams for MFCs. Despite major advances in the past decade, further improvements in MFC power output and cost reduction are needed for MFCs to be practical. This paper analysed MFC operating principles using bioenergetics and bioelectrochemistry. Several major issues were explored to improve the MFC performance. An emphasis was placed on the use of catalytic materials for MFC electrodes. Recent advances in the production of various biomaterials using MFCs were also investigated.
TL;DR: In this paper, a bipolar membrane was used to separate the anode and the cathode chambers to overcome the thermodynamic barrier for hydrogen production from acetate, which achieved a 3.9% anode efficiency and 41% cathode efficiency.
TL;DR: In this paper, two chamber microbial electrolysis cells (MECs) were examined for the effectiveness and energy efficiency for cobalt leaching from particulate lithium cobalt oxide, one main cathodic component in spent Li-ion batteries.
TL;DR: It turns out that to reduce the anodic energy loss caused by overpotential, higher substrate concentrations are preferred, if the substrate do not significantly and adversely affect the output current.