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Wireless Sensors Powered by Microbial Fuel Cells
Abstract
Monitoring parameters characterizing water quality, such as temperature, pH, and concentrations of heavy metals in natural waters, is often followed by transmitting the data to remote receivers using telemetry systems. Such systems are commonly powered by batteries, which can be inconvenient at times because batteries have a limited lifetime and must be recharged or replaced periodically to ensure that sufficient energy is available to power the electronics. To avoid these inconveniences, a microbial fuel cell was designed to power electrochemical sensors and small telemetry systems to transmit the data acquired by the sensors to remote receivers. The microbial fuel cell was combined with low-power, high-efficiency electronic circuitry providing a stable power source for wireless data transmission. To generate enough power for the telemetry system, energy produced by the microbial fuel cell was stored in a capacitor and used in short bursts when needed. Since commercial electronic circuits require a minimum 3.3 V input and our cell was able to deliver a maximum of 2.1 V, a DC-DC converter was used to boost the potential. The DC-DC converter powered a transmitter, which gathered the data from the sensor and transmitted it wirelessly to a remote receiver. To demonstrate the utility of the system, temporal variations in temperature were measured, and the data were wirelessly transmitted to a remote receiver.
... In this grim scenario, MFCs prove their suitability for self-powering electrochemical sensors. Thus, for pollutant analysis and process monitoring, MFC technology discloses a new path for the development of various sensors such as biological oxygen demand (BOD) sensor, enzymatic glucose sensor, etc. [11,12]. ...
... The cost is less than that of the conventional biosensor since the transducer is unnecessary in MFC-based biosensor. Additionally, these sensors can be operated for more than five years without maintenance [11,13]. For rapid and sensitive results of environmental monitoring, biosensors generally follow strict regulations and higher standards for the detection of pollutants. ...
Microbial Fuel Cells (MFCs) are a rapidly developing technology that has fascinated scientists and engineers; especially those who are challenged by energy production and wastewater treatment. With adequate modifications, MFCs could be useful for various applications that range from environmental bioremediation to being power sources for environmental sensors. Therefore, MFC-based electrochemical sensors can be used for pollutant analysis and process monitoring. This technology also helps in the polluted lake and river water by remediating the toxicity of phenols, petroleum compounds, toluene, and benzene. Some limitations related to MFC sensors include the requirement of power for operation and difficulty in accessing the system. To overcome these limitations, sediment fuel cells are developed to monitor beyond-reach environmental systems such as creeks, rivers, and oceans. Nowadays, MFCs have an increasing number of applications, this chapter will provide further details on the environmental applications of Microbial Fuel Cells.
... Donovan et al. [118] and Shantaram et al. [119] created MFC-powered wireless sensors using a standard step-up converter and charge pumps (Table 3a). However, the power conversion efficiency of these PMSs, designed to harvest energy from a single MFC, could be better. ...
... Using a standard step-up converter and charge pumps [119]. ...
Microbial electrochemical technologies (METs) holds promise for converting waste into electrical power and hydrogen generation. Transitioning from lab to real-world applications faces challenges, but successful largescale demonstrations and industrial use demonstrate readiness. Startups invest in pilot-scale research for industrial METs. To enhance MET energy production, specifically microbial fuel cells (MFCs) for powering appliances, research should focus on efficient power management systems (PMS). Developing a renewable energy source for remote monitoring applications is a challenge. METs and PMS can power low- and constant-power applications like environmental monitoring in IoT systems. Aligning with sustainable development goals, operating energy-consuming microbial electrolysis cells (MECs) and microbial electrosynthesis cells (MESCs) for biofuel production using net-zero energy harvesting technologies is crucial. This review critically assesses METs in waste-to-energy, industrialisation, practical circuitry, PMS, integration of METs into wireless monitoring, and carbon-neutral operation. It presents an updated life cycle analysis (LCA) of integrated METs and proposes advanced, pragmatic MET operations.
... 31,84 Appropriate cathodic and anodic reactions are suitable steps to design biosensors. 84 MFCs are used as biological oxygen demand (BOD) sensor 20 which has suitable sustainability to work for 5 years. 18 ...
... In addition, MFCs cannot be operated at exceptionally low temperatures since they slow down the rate of microbial reactions as microbes require a suitable temperature for the ionic reactions. 84 The important need for practical use is the increment in the size of the reactor of MFCs and its capacity for profuse output. The main objective of MFCs is seen in the field of wastewater treatment and in electricity generation. ...
There is global crisis due to fuel depletion and environmental pollution. The dependency on fossils for fuels is unsustainable due to its finite nature, so researchers are studying alternative sources of energy that are renewable in nature. A microbial fuel cell (MFC) is the device used to generate energy by converting chemical energy into electrical energy by the series of catalytic reactions of anaerobic microorganisms. Recently MFC are in the developing phase due to the use of biodegradable substances for fuel. Not only does it produce electricity but it has many other applications as well like wastewater treatment, biohydrogen production and biosensors. It is based on various parameters and has several configurations for the higher energy output. This review studies about MFCs history, working, types, components, designs, factors affecting the MFCs, applications and its future scope.
... Moreover, the operational performance of MFCs can be highly affected by the variation in the composition of the microorganisms, type, concentration of the organic matter in the influent system, and environmental conditions that lead to an MFC system with instability and reduced performance. These factors may lead to the power inadequacy to run an MFC system and make it challenging to use them for large-scale applications [153]. ...
... Seasonal factors, e.g., temperature, humidity, etc., influence the performance of MFCs. In low-temperature seasons and regions, the growth of microbes is influenced by suppressing the metabolism that tends to decrease in electron excretion [153]. One of the most critical issues in MFC operation is the biofouling of a membrane that reduces the efficiency of the proton transfer rate in the cell. ...
A microbial fuel cell (MFC) is a system that can generate electricity by harnessing microor-ganisms' metabolic activity. MFCs can be used in wastewater treatment plants since they can convert the organic matter in wastewater into electricity while also removing pollutants. The microorganisms in the anode electrode oxidize the organic matter, breaking down pollutants and generating electrons that flow through an electrical circuit to the cathode compartment. This process also generates clean water as a byproduct, which can be reused or released back into the environment. MFCs offer a more energy-efficient alternative to traditional wastewater treatment plants, as they can generate electricity from the organic matter in wastewater, offsetting the energy needs of the treatment plants. The energy requirements of conventional wastewater treatment plants can add to the overall cost of the treatment process and contribute to greenhouse gas emissions. MFCs in wastewater treatment plants can increase sustainability in wastewater treatment processes by increasing energy efficiency and reducing operational cost and greenhouse gas emissions. However, the build-up to the commercial-scale still needs a lot of study, as MFC research is still in its early stages. This study thoroughly describes the principles underlying MFCs, including their fundamental structure and types, construction materials and membrane, working mechanism, and significant process elements influencing their effectiveness in the workplace. The application of this technology in sustainable wastewater treatment, as well as the challenges involved in its widespread adoption, are discussed in this study.
... There have been reports of columbic efficiencies of up to 80% [24,25], allowing for the removal of up to 90% of the COD [26]. • MFCs in biosensors: MFCs are convenient for fuelling electrochemical sensors and are compact telemetry systems for transmitting data to distant receivers due to the batteries' limited lifetime and recharging requirements [27,28]. Using MFCs as a sensor for biological oxygen demand (BOD) has been shown to work [28]. ...
... • MFCs in biosensors: MFCs are convenient for fuelling electrochemical sensors and are compact telemetry systems for transmitting data to distant receivers due to the batteries' limited lifetime and recharging requirements [27,28]. Using MFCs as a sensor for biological oxygen demand (BOD) has been shown to work [28]. This kind of sensor for BOD has excellent reproducibility and operational sustainability and can be kept running for 5 years [29]. ...
Over the last two decades, scientific communities have been more interested in turning organic waste materials into bioenergy. Microbial fuel cells (MFC) can degrade organic wastewater and produce electrical power. Many constraints have limited the development of MFC. Among them, the anode biofilm development is one of the significant constraints that need to be improved. This review delineates the role of various biological components in the development of electroactive biofilm. The current article focuses on the numerous electron exchange methods for microbiome-induced electron transfer activity, the different proteins, and secretory chemicals involved in electron transfer. This study also focuses on several proteomics and genomics methodologies that have been adopted and developed to improve the extra electron transfer mechanism in electroactive bacteria. Recent advances and publications on synthetic biology and genetic engineering in investigating the direct and indirect electron transport phenomena have also been highlighted. This review helps the reader to understand the recent development in the genetic manipulations of the biofilm, electrode material modifications, EET mechanisms, and operational strategies for improving anode performance. This review also discusses the challenges in present technology and the future direction for improving biofilm production at the anode.
... MFCs are categorized into two types based on the mechanism by which microorganisms transfer the electrons to the anode. These categories are the mediator-based MFCs and the mediator-free MFCs (Shantaram et al., 2005). Chemical mediators are introduced to allow bacteria that are unable to create electricity using the electrode to do so. ...
... Chemical oxidizers like ferricyanide or Mn (IV) can also be adopted; however, these chemical oxidizers must be regenerated frequently . Bacteria play a catalytic role in the reoxidation of metals like Mn (IV) to Mn (II) via utilizing dissolved oxygen (Shantaram et al., 2005). The distinguishing properties of an MFC are the electron liberation via microbial catalysis at the anode and the consequent electron consumption at the cathode. ...
The accelerated growth of population and industrialization led to increased demand for clean water resources. The abundance of wastewater produced daily can often make its way into the environment without sufficient treatment. This led to a necessity in developing technologies to invest in solving this global problem. The integration of forward osmosis (FO) into microbial fuel cells (MFCs) is among the proposed technologies to solve some of the existing problems related to water treatment. Not only does this invention contribute to treating wastewater, but it also produces clean water, and generates renewable energy at a low cost. This chapter is devoted to discussing membrane transport theory, FO, MFC, and the combination of FO and MFC as osmotic microbial fuel cells (OsMFCs). Furthermore, the chapter aims at illustrating various designs and configurations of MFCs, targeting the optimization of their applications. It discusses the challenges and limitations of OsMFC and their maintenance while providing case studies on the application of OsMFCs for wastewater treatment. The environmental impacts of OsMFCs have been presented in this context.
... Alternatively, a super-capacitor can be introduced into the system to store energy. The accumulated energy can be released when adequate to support the operation of the sensor 220,221 . Perturbation in power output can also occur under fluctuating environmental conditions 214 . ...
... In recent years, they have also provided insights into the fundamental nature of electroactivity in different classes of microbes, including Gram-positive bacteria (7,8), pathogenic bacteria (9)(10)(11), and weak electricigens (12)(13)(14). On the applied side, BESs have branched out into several applications, including wastewater treatment (15,16), heavy metal recovery (17,18), biosensing of hazardous chemicals (19,20), powering remote sensors (21,22), and even monitoring and removal of viral antigens in a medical context (23). ...
Cable bacteria are filamentous bacteria that couple the oxidation of sulfide in sediments to the reduction of oxygen via long-distance electron transport over centimeter distances through periplasmic wires. However, the capability of cable bacteria to perform extracellular electron transfer to acceptors, such as electrodes, has remained elusive. In this study, we demonstrate that living cable bacteria actively move toward electrodes in different bioelectrochemical systems. Carbon felt and carbon fiber electrodes poised at +200 mV attracted live cable bacteria from the sediment. When the applied potential was switched off, cable bacteria retracted from the electrode. qPCR and scanning electron microscopy corroborated this finding and revealed cable bacteria in higher abundance present on the electrode surface compared with unpoised controls. These experiments raise new possibilities to study metabolism of cable bacteria and cultivate them in bioelectrochemical devices for bioelectronic applications, such as biosensing and bioremediation.
IMPORTANCE
Extracellular electron transfer is a metabolic function associated with electroactive bacteria wherein electrons are exchanged with external electron acceptors or donors. This feature has enabled the development of several applications, such as biosensing, carbon capture, and energy recovery. Cable bacteria are a unique class of long, filamentous microbes that perform long-distance electron transport in freshwater and marine sediments. In this study, we demonstrate the attraction of cable bacteria toward carbon electrodes and demonstrate their potential electroactivity. This finding enables electronic control and monitoring of the metabolism of cable bacteria and may, in turn, aid in the development of bioelectronic applications.
... A PEM is used to separate the two chambers allowing for better control over the environmental conditions and electrode materials in each compartment (Fig. 3). (Amend & Shock, 2001), wastewater treatment (Zhou et al., 2013), biosensor (Shantaram et al., 2005), hydrogen production, research and other large-scale applications (Ullah & Zeshan, 2020). ...
In recent years, governmental agencies have imposed stringent environmental discharge norms for biological nutrients (N and P). As an alternate green treatment technology, Microbial Fuel Cell (MFC) was developed with an aim to reduce the operational cost of treatment plants as well as energy recovery as a bi-product. Looking into this matter, the present paper summarizes different aspects of MFC as a working principle for biological nutrient removal mechanisms, its types, reactor configurations, and case studies. Contemporary research showed, that along with treating wastewater, MFC also promises electricity generation. However, it is observed from the bench scale and real-life case studies that the generated electricity is not sufficient to replace the conventional power sources. The latest study showed that this technology is effective in treating only 850 L of wastewater for over 6 months, which is much lower than the capacity of prevailing treatment plants. To overcome these limitations, the present study proposes a conceptual model to integrate MFC into existing wastewater treatment facilities.
... According to Rahimnejad et al. [66], this takes place whenever an ultra-capacitor is used. Since microbial processes are slower at extreme temperatures, MFC is unable to function at temperatures below room temperature [67]. Over the course of the last two decades, a considerable amount of efort and time has been spent in the research, advancement, and improvement of electrode substances with the intention of enhancing the efciency of MFCs. ...
Microbial fuel cell (MFC) is a new and interesting technology that can be used to treat wastewater without using electricity. The current research focuses on electron generation, which is one of the technique’s major challenges. According to the latest literature, the study was planned to successfully remove the metals from artificial wastewater at high concentrations and generate electricity. On average, after 18 days of operation, it offered 610 mV with 1000 ῼ constant external resistance. The internal resistance was found to be 520 ῼ. The achieved power density was 3.164 mW/m2 at an external resistance of 1000 ῼ. The achieved removal efficiencies of Pb2+, Cd2+, Cr3+, and Ni2+ were 83.67%, 84.10%, 84.55%, and 95.99%, respectively. The operation lasted for 25 days. The cyclic voltameter studies show that there is a gradual oxidation rate of organic substances, while on day 25, the removal efficiency reached its maximum. The specific capacitance was found to be high between days 15 and 20, i.e., 0.0000540 F/g. It also indicated that biofilm was stable around day 18. Furthermore, the biological characterization also demonstrated that MFC operation was very smooth throughout the process, even at high concentrations (100 mg/L) of metal ions. Finally, there is the MFC method, as well as some new challenges and future recommendations.
... These sensors can monitor a variety of variables, including temperature, pH, dissolved oxygen, and substrate concentration, and provide real-time feedback to assist in optimizing the process and achieving maximum product yield. For instance, a wireless sensor system for monitoring microbial fuel cells that provides real-time data on the voltage output and substrate concentration has been developed [87]. In a variety of biosimilar monitoring applications, including biosensing and diagnostics [88], medication delivery systems [89], quality control [90], environmental monitoring [91], and bioprocessing, wireless antenna sensors have demonstrated significant promise. ...
The integration of wireless antenna sensors for cyber-physical systems has become increasingly prevalent in various biosimilar applications due to the escalating need for monitoring techniques that are efficient, accurate, and reliable. The primary objective of this comprehensive investigation is to offer a scholarly examination of the present advancements, challenges, and potentialities in the realm of wireless antenna sensor technology for monitoring biosimilars. Specifically, the focus will be on the current state of the art in wireless antenna sensor design, manufacturing, and implementation along with the discussion of cyber security trends. The advantages of wireless antenna sensors, including increased sensitivity, real-time data gathering, and remote monitoring, will next be discussed in relation to their use in a variety of biosimilar applications. Furthermore, we will explore the challenges of deploying wireless antenna sensors for biosimilar monitoring, such as power consumption, signal integrity, and biocompatibility concerns. To wrap things off, there will be a discussion about where this subject is headed and why collaborative work is essential to advancing wireless antenna sensor technology and its applications in biosimilar monitoring. Providing an in-depth overview of the present landscape and potential developments, this article aims to be an asset for academics and professionals in the fields of antenna sensors, biosimilar development, wireless communication technologies, and cyber physical systems.
... The main practical challenges and limitations associated with bioelectricity generation using MFCs are; low power output, current instability, high internal resistance, expensive materials, nature of inoculum type, variation in the concentration of the substrate, regular cleaning and maintenance of MFC container. Also, operational conditions such as pH and temperature affects the microbial activities in the MFC especially at temperature below 20°C (Shantaram et al., 2005). As shown in Table 1, The anodic bacterial isolates were identified by microscopic and biochemical characteristics. ...
Microbial fuel cells (MFCs) are technologies that directly transform chemical energy into electrical energy by oxidizing organic matter using bacteria as biocatalysts. MFCs offer a potential technology for converting wastewater into useful energy source and at the same time serve as wastewater treatment facilities. This makes it superior to other wastewater treatment methods. This study focused on the utilization of MFCs to generate bioelectricity from sewage wastewater using cow urine as inoculum and identify the bacteria colonizing the anode electrode. The experiment were conducted using two-chambered MFC constructed using locally sourced materials. Wastewater was characterized using standard methods. The characteristics of the sewage wastewater are: 680 mg/L Chemical oxygen Demand (COD), 457 mg/L Biochemical oxygen Demand (BOD) and pH of 7.4. The maximum voltage, power and current density obtained were 196 mV, 18.26 mW/m2 and 97 mA/m2 respectively. The MFC shows a reduction in COD value by 82 % (680mg/L initial and 120 mg/L final).The identification of the anodic biofilms showed the presence of Bacillus spp and klebsiella spp based on their microscopic and biochemical characterization. The results of this study can contribute to improve understanding and optimizing electricity generation in MFC, Further study would be conducted in order to identify the microorganisms at molecular level.
... Since most of the microbial species used in the MFC system are mesophilic, the maximum efficiency has been recorded at 30-45 °C ( Rossi et al., 2017 ;Hamed et al., 2021 ). Studies have also shown that a lower temperature below 20 0 C can restrict microbial activity and reduce output voltage ( Shantaram et al., 2005 ). ...
... The kinetics of MFC system is influenced by temperature variations as microbial reactions begin to cease at temperatures below 20 °C (Shantaram et al. 2005). This condition greatly affects MFCs performance. ...
The main objective of the study was to isolate and characterize microalgae from Vellar estuary south coast of India. The isolated eight microalgal species were cultured in CHU 10 broth to find the efficient culture media under laboratory conditions. The growth rate, pH, and biomass for lipid production under different conditions were studied from the eight microalgal species isolated and incubated in different media. On the other hand, the physicochemical properties of sewage water were analyzed, and the suitable environmental condition was adopted for culturing. Microalgae showed good growth, and the biomass was taken for further study among which Nitzschia species was selected based on biomass and lipid production. Further, enhancement was carried out by supplementing media with different carbon (glucose and starch) and nitrogen (urea and yeast) sources. Nitzschia species resulted in a maximum growth rate (2.08) and biomass (0.17 g L−1) with glucose as carbon source, while supplemented yeast as nitrogen source yielded a maximum growth rate (1.118) and urea favored the maximum biomass (0.16 g L−1). Maximum lipid content about 0.058 and 0.046 g was witnessed when supplementing the glucose and yeast along with the diatom media components (0.025 g). The oil was characterized by FT-IR spectroscopy, and different active functional groups were recorded. In Nitzschia, 98% of different fatty acids were recorded. The present study concluded that the culture conditions, especially the nature of carbon and nitrogen sources, influence the yield on growth, biomass, and lipid production of Nitzschia sp.KeywordsMicroalgaeSewage waterBiomassNitzschia sp.LipidMedia components
... The kinetics of MFC system is influenced by temperature variations as microbial reactions begin to cease at temperatures below 20 °C (Shantaram et al. 2005). This condition greatly affects MFCs performance. ...
Weeds are invasive or unwanted plants that are non-native to the ecosystem grow along with food crops threatening the food security, health, economic development and biodiversity. They are competitive, able to persist and grow under any stressed conditions with high propagating capability. India having temperate to tropical zones possesses rich plant diversity spread across different crop and non-croplands. Weeds grow everywhere consuming the nutrients, soil moisture, space, etc., meant for food crops and thus ultimately affect the crop productivity adversely. Parthenium is a weed that invaded India with imported food grains in the mid-1950s. This weed alone was reported (2001–2007) to invade over 14.5 million hectares of farmland in India (Directorate of Weed Science Research—DWSR). It was also opined that the swift growth of this weed is a threat to environment, biodiversity and country’s economy. Various strategies involving many voluntary organizations, individuals and government agencies in the weed management on a regional scale were organized. Though several eradication measures were undertaken in this regard, not a single method is still a choice for the complete eradication of weed. Therefore, the status of weed controlling is envisaged with respect to “large-scale utilization”. Over a century, several studies have been reported that weed can be a potential biomass. Weed can be used as a green manure, biocontrol agent, soil ameliorate, compost which in turn improves physical, chemical and biological composition of the soil and also in the generation of significant quantities of energy. In this age of renewable energy, there is an ever-rising demand for the alternative energy source which calls for exploring and exploiting new sources of energy biomethanation is a process of production of biogas (methane), during which the organic matter is converted into an alternative fuel. Biomethanation offers an effective way to manage the weed biomass in eco-friendly and cost-effective way.
... The kinetics of MFC system is influenced by temperature variations as microbial reactions begin to cease at temperatures below 20 °C (Shantaram et al. 2005). This condition greatly affects MFCs performance. ...
Bioenergy is energy produced from organic material of plant and animal sources, mainly agricultural residues, wood, energy crops, and organic wastes. Bioenergy is the most common renewable energy source globally, accounting for roughly 70% of all critical renewable energy sources. Since biomass is organic, it is one of the most dependable energy sources. Traditional biomass is used by about 2.5 billion people worldwide and about 1.3 million public, specifically children and women, every year prematurely die. Biological resources are agricultural residues, industrial waste, municipal solid waste, and terrestrial and aquatic crops grown only for energy purposes. Agricultural residues are an essential energy source, and rice is a chief crop in several emerging countries, especially Asia. Rice bran and rice straw, which are remnants of this crop, have a high potential for bioenergy production. The source of bioenergy is rice grass, lignocellulosic biomass, lignin, cellulose, and hemicellulose. Rice straw is also used to generate electricity; the fundamental method is a thermochemical one that generates steam via direct combustion of biomaterials. This form, however, is highly undesirable due to the detrimental effects on the environment caused by the release of carbon dioxide and methane gas. Consequently, it is imperative to progress a method of extracting energy from rice straw to generate electricity. It is an excellent approach to dispose of rice straw and uses heat is helpful for power generation. Eventually, rice straw can be used in high-efficiency, energy production, and affordable agro-biometry to generate electricity and evaluate bioenergy and its impacts in the sense of the particular framework of which it is a part, as well as their direct and broader impacts on the environment and economy.
... MFCs were also used as sensor for pollutant monitoring. As electrical batteries have limited lifetime the MFC can be used for powering the chemical sensor and telemetry system to transmit data to receiver [117], [118]. MFC technology clubbed with membrane bioreactor were used for direct water reclamation after the wastewater treatment. ...
Crude oil and coal reserves remaining nearly fifty times and one hundred thirty times of current yearly consumption, respectively, the world economy is trying to shift to a more renewable energy-dependent model. Global renewable energy production increased by nearly 60% from 2011 to 2020. Among the renewable energy sources bioenergy provide a prominent portion. Bioenergy can be in form of biogas, liquid biofuels, solid biofuel, etc. However, direct production of electricity by means of biochemical reactions can be done with microbial fuel cells (MFCs). This is an eco-friendly way to produce energy while treating wastewater. In MFCs one anode and one cathode separated by a proton exchange membrane (PEM) are present. Microorganisms present inside the anode chamber produce electron (e–) and proton (H+) after oxidation of organic matters present in wastewater. These electrons are transferred to the cathode chamber through an external connection while the protons pass through a semipermeable membrane called proton exchange membrane (PEM). These electrons and protons react inside the cathode chamber in presence of oxygen to form water. The electron is transferred to the anode from microbes directly through pili/nanowire, a conductive appendage of microbe, or by indirect mechanism using career compounds like pyocyanine, thionin. MFCs can be many types depending on the presence of membrane, presence of liquid in cathode chamber, number of chambers, number of electrodes, type of PEM, the direction of flow, electrode material, etc. MFCs are successfully tested to treat domestic wastewater as well as wastewater from different industries like brewery, paper and pulp, pharmaceutical, food processing. Other than a standalone MFC system this technology is applied as a hybrid system with anaerobic-anoxic–oxic (AO/O) treatment, membrane bioreactor treatment, constructed wetland treatment, etc. This technology is also used as toxicity sensor as well as BOD sensor. In recent years, many researchers are working on improving the scalability of MFC technology. Production of electricity using MFC from human excreta and urine while acting as a treatment facility has also grabbed the attention of many in recent years. However, until economic sustainability is fully achieved for large-scale MFCs mass scale adoption of this technology cannot be attained.KeywordsMicrobial fuel cellWaste to energyAnaerobic treatmentElectricity productionWastewater treatment
... SMFCs are capable of converting a wide range of organic materials in aquatic ecosystems to electricity [10], by being installed directly in marine environments or as well rivers [11,12]. River water has lower electrical conductivity ($500 vs $ 50,000 μS/cm at 20oC) and higher electrolyte resistance than seawater, which hence results in greater production of electrical energy by seawater sediments [8]. ...
... The catholyte used 35 g/L NaCl, and the power density of the air cathode OsMFC is 8% and 87% higher than that of the MFC with AEM and CEM, respectively. Generally, the performance of MFC was evaluated by open circuit voltage and internal loss, including ohmic loss, activation loss, microbial metabolism loss, and concentration loss [26]. When the reactor configuration and electrolyte were the same, the open circuit voltages of OsMFC and MFC were not the same. ...
As a new membrane technology, forward osmosis (FO) has aroused more and more interest in the field of wastewater treatment and recovery in recent years. Due to the driving force of osmotic pressure rather than hydraulic pressure, FO is considered as a low pollution process, thus saving costs and energy. In addition, due to the high rejection rate of FO membrane to various pollutants, it can obtain higher quality pure water. Recovering valuable resources from wastewater will transform wastewater management from a treatment focused to sustainability focused strategy, creating the need for new technology development. An innovative treatment concept which is based on cooperation between bioelectrochemical systems and forward osmosis has been introduced and studied in the past few years. Bioelectrochemical systems can provide draw solute, perform pre-treatment, or reduce reverse salt flux to help with FO operation; while FO can achieve water recovery, enhance current generation, and supply energy sources for the operation of bioelectrochemical systems. This paper reviews the past research, describes the principle, development history, as well as quantitative analysis, and discusses the prospects of OsMFC technology, focusing on the recovery of resources from wastewater, especially the research progress and existing problems of forward osmosis technology and microbial fuel cell coupling technology. Moreover, the future development trends of this technology were prospected, so as to promote the application of forward osmosis technology in sewage treatment and resource synchronous recovery
... Keeping all the parameters in mind, a perfect scale-up process is difficult to achieve and for the proper working of the MMFC, a constant voltage supply is required. The output of voltage that would generally be achieved is usually imbalanced and low at the same time which made it difficult for Shantaram et al. [101] to maintain a stable power output.. To counter voltage instability, checking and adjusting microbial concentrations, the volume of the oxidizing agent, and functional parameters at regular interval is necessary alongside optimizing them as per the need. The problem of internal resistance was observed at the electrodes which were hindering the proficiency of the movement of [100] electrons and thus limiting the outcome of MFC. ...
Microalgae have shown their extravagant potency as a prominent source for the production of biomass, which has opened the gates for biofuel, bioenergy generation, and down-streaming in today’s third-world developing countries. They are competent in producing smaller land footprints while engendering high yields of biomass and fuel overall. By their nature, they have the potential to avail the land that is incapacitated for food production and flourishes there without bringing forth disruption to the economy in any form. Since microalgae are perennial along with excellent tolerance towards pH changes, their current demand is skyrocketing. The review paper, sails on the generation of biohydrogen, biomethane, and bioelectricity using microalgae as the primordial constituents, with the mechanisms and pitfalls confronted throughout the process. Alongside, this paper also covers the involvement of microalgae in the treatment of wastewater and biohydrogen production using dark fermentation. Biomethane is one of the prime biogas generated upon methanogenesis and fermentation when carried out employing microalgae. The paper’s greater aims are also to highlight the production of bioelectricity using microbial electrochemical cells and microbial fuel cells. The outcome of this review can provide a research update on the efficiency of algal biomass as a promising raw material for various biofuels paving a way for finding research gaps towards future exploration.
The chemistry of the extracellular electron transfer (EET) process in microorganisms can be understood by interfacing them with abiotic materials that act as external redox mediators. These mediators capture and transfer extracellular electrons through redox reactions, bridging the microorganism and the electrode surface. Understanding this charge transfer process is essential for designing biocapacitors capable of modulating and storing charge signatures as capacitance at the electrode interface. Herein, a novel biointerfacial strategy is presented to investigate directional charge injection from a non‐exoelectrogenic living microbe to an electrode surface using the porous metal–organic framework (MOF), MIL‐88B. The biohybrid, formed by interfacing Escherichia coli (E. coli) with MIL‐88B, demonstrates symbiotic interactions between the biotic and abiotic components, facilitating EET from E. coli to the electrode via the MOF. Acting as a redox mediator, the MOF catalyzes E. coli's exoelectrogenic activity, generating distinct charge capacitive signatures at the E. coli‐MOF interface. This system integrates the capacitive signatures resulting from the EET process with the MOF's intrinsic pseudocapacitive properties and surface‐controlled capacitive effects, functioning as a highly efficient biocapacitor. Furthermore, this approach of converting the biochemical energy of a non‐exoelectrogenic microorganism into capacitive signatures opens a new pathway for translating biological signals into functional outputs, paving the way for autonomous biosensing platforms.
Conventional wastewater treatment processes, being significant energy consumers, are not sufficiently adapted to the ongoing energy challenges. In this context, the use of electroactive microorganisms in bioelectrochemical systems has grown, primarily focusing on microbial fuel cell technology. Microbial fuel cells, exploiting the electrogenic properties of specific bacteria, provide a sustainable solution by concurrently treating wastewater and generating electric power in treatment plants. This technology transforms wastewater treatment plants into potential net energy producers through the oxidation of organic matter and bioelectricity generation by microorganisms. This chapter thoroughly describes microbial fuel cells, encompassing its various types and essential operational factors influencing its efficiency in wastewater treatment and bioelectricity generation. Recent advancements and breakthroughs in addressing diverse wastewater types are explored alongside analysing associated challenges and their prospects. This chapter objectively assesses the challenges of energy deficiency and high expenditure in microbial fuel cells for wastewater treatment. It explores microbial fuel cell applications and proposes integration with other treatment processes to enhance the practicality and effectiveness of contaminant removal on a larger scale. The aim is to provide valuable insights for overcoming limitations and promoting microbial fuel cell integration in comprehensive wastewater treatment strategies.
The energy consumption, residual generation, and inability to extract energy from
wastewater are only a few of the constraints that current wastewater treatment
methods face. Conventional aerobic-activated sludge treatment methods, for instance, are frequently noted for being energy intensive, producing a lot of residual
waste, and being unable to recover the potential resources present in wastewater.
Depending on the procedure and wastewater composition, wastewater treatment requires roughly 0.5-2 kWh/m3; yet strangely, wastewater contains about 3e10 times the energy needed to treat it (Gude, 2015).
In this chapter, we explore the fascinating realm of bioelectrochemical systems (BES) and their role in powering various sensors crucial for diverse applications, including water quality analysis, medical diagnostics, environmental monitoring, and plant growth analysis.
Recent advancements in sensor technologies, electronics, and wireless communication have revolutionized sensor operations, enabling their widespread integration across multiple technological domains such as engineering, medical sciences, chemistry, and agriculture.
By advocating for the adoption of BES over conventional techniques, we endorse a sustainable approach to development, wherein waste management and energy production occur simultaneously. Specifically, microbial fuel cells (MFCs) and microbial carbon capture cells (MCCs) emerge as promising alternatives, offering cost-effective and clean energy solutions for powering water quality sensors and beyond.
With the ever-increasing demand for reliable renewable energy sources, BES holds immense potential across modern technological scenarios. Further research endeavors are crucial to enhance the performance and efficacy of these systems, particularly in the context of wastewater utilization and renewable energy production.
This chapter not only highlights future research perspectives on BES but also provides valuable insights into its potential as both biosensors and power supplies for diverse sensor applications, paving the way for the development of cutting-edge technologies.
Devastating environmental health which is associated with many factors of which one is improper sanitation of water, uncontrolled release of many toxic organic contaminants from the modern industries had exploited the nature a lot. The major causes for environmental pollution and depletion in the quality of surface and ground water bodies are wastewater which comes from many ways. The exhaustible usage of non-renewable sources of energy (coal, oil, natural gas, etc.) are not confined to developing countries alone but are the worldwide along. Recent advancement in the Microbial Fuel Cell (MFC) technology may serve as an eco-friendly, sustainable and the best accepted way to conserve environment and meet the criterion for the water sanitation needs. Ongoing waste water treatment technologies are less effective when it comes to sustainability, as there is rapid growth in population and industrialization and hence sudden increase in the exploitation of resources combinedly, had given researchers insight to brought such a novel technique which can serve the purpose of water sanitation along with the energy yielding conserving of the environment. MFC technology has proven the efficient mode for the generation of energy by transforming the organic waste into the electricity through microbially catalysed anodic, and microbial/enzymatic/abiotic cathodic electrochemical reactions using various redox mediators. To enhance the electron transfer between microorganisms and electrode the redox mediators are majorly used in MFC or microbial electrochemical systems. To produce electricity from the oxidation of organic compounds by using the bio-electrochemical catalytic activity of microbes which in turns uses wastewater as a source for the same, hence reducing the contaminants from wastewater. In some cases, the sources can be industrial wastewater, substrates present in urban sewage, agriculture, food, dairy industries, etc. Thus, scientists are aiming to construct the effective microbial fuel cell or microbial electrochemical systems for generation of electricity and wastewater treatment simultaneously. Besides so many benefits come along with this technology, it still faces practical barriers such as low production of power and electric current density. To determine the real potential of the MFC technology for sustainable and energy generating wastewater treatment, some remarkable investigation or important discoveries in electrode materials, innovative and integrated methods configurations are urgent requirement. In the present article different parts of MFC such as anode, cathode, membrane, redox mediators and also basic mechanism of the microbial electrochemical systems or MFC for wastewater treatment and production of energy have been reviewed.
Microbial fuel cells (MFCs) have been gaining attention as a promising technology for sustainable energy production through the metabolic processes of microorganisms. The materials traditionally employed in this field have fallen short in facilitating efficient microbial-electron transfer and subsequent current generation, posing significant challenges for practical applications. To overcome this hurdle, the integration of nanomaterials into MFC components has emerged as a promising avenue, capitalizing on their unique physical and chemical properties to drive iterative advancements. In this review article, we explore the importance of nanomaterials in MFCs, highlighting their exceptional attributes such as high surface area-to-volume ratio, stability, durability, and selectivity. These advancements could hold the key to accelerating the recognition of MFCs as a powerful platform technology.
Extensive study on renewable energy storage has been sparked by the growing worries regarding global warming. In this study, incorporating the latest advancements in microbial electrochemistry and electrochemical CO2 reduction, a super‐fast charging biohybrid battery was introduced by using pure formic acid as an energy carrier. CO2 electrolyser with a slim‐catholyte layer and a solid electrolyte layer was built, which made it possible to use affordable anion exchange membranes and electrocatalysts that are readily accessible. The biohybrid battery only required a 3‐minute charging to accomplish an astounding 25‐hour discharging phase. In the power‐to‐formate‐to‐bioelectricity process, bioconversion played a vital role in restricting both the overall Faradaic efficiency and Energy efficiency. The CO2 electrolyser was able to operate continuously for an impressive total duration of 164 hours under Gas Stand‐By model, by storing N2 gas in the extraction chamber during stand‐by periods. Additionally, the electric signal generated during the discharging phase was utilized for monitoring water biotoxicity. Functional genes related to formate metabolism were identified in the bioanode and electrochemically active bacteria were discovered. On the other hand, Paracoccus was predominantly found in the used air cathode. These results advance our current knowledge of exploiting biohybrid technology.
Extensive study on renewable energy storage has been sparked by the growing worries regarding global warming. In this study, incorporating the latest advancements in microbial electrochemistry and electrochemical CO2 reduction, a super‐fast charging biohybrid battery was introduced by using pure formic acid as an energy carrier. CO2 electrolyser with a slim‐catholyte layer and a solid electrolyte layer was built, which made it possible to use affordable anion exchange membranes and electrocatalysts that are readily accessible. The biohybrid battery only required a 3‐minute charging to accomplish an astounding 25‐hour discharging phase. In the power‐to‐formate‐to‐bioelectricity process, bioconversion played a vital role in restricting both the overall Faradaic efficiency and Energy efficiency.The CO2 electrolyser was able to operate continuously for an impressive total duration of 164 hours under Gas Stand‐By model, by storing N2 gas in the extraction chamber during stand‐by periods. Additionally, the electric signal generated during the discharging phase was utilized for monitoring water biotoxicity. Functional genes related to formate metabolism were identified in the bioanode and electrochemically active bacteria were discovered. On the other hand, Paracoccus was predominantly found in the used air cathode. These results advance our current knowledge of exploiting biohybrid technology.
Cable bacteria couple the oxidation of sulphide in sediments to the reduction of oxygen via long-distance electron transfer through periplasmic wires. While direct electron transfer between cable bacteria cells belonging to the same filament is a well-known phenomenon, electron transfer from the filament to electrodes has remained elusive. In this study, we demonstrate that living cable bacteria are attracted to electrodes in different bioelectrochemical systems. Carbon felt and carbon fibre electrodes poised at +200 mV against an Ag/AgCl reference attracted live cable bacteria from the sediment. When the applied potential was switched off, cable bacteria retracted from the electrode. qPCR and scanning electron microscopy corroborated this finding and revealed cable bacteria adhered onto the electrode surface. These experiments raise new possibilities to cultivate cable bacteria and utilise them for important applications in bioelectrochemical systems.
Providing the reader with an up-to-date digest of the most important current research carried out in the field, this volume is compiled and written by leading experts from across the globe. It reviews the trends in electrochemical sensing and its applications and touches on research areas from a diverse range, including microbial fuel cells, 3D printing electrodes for energy conversion and electrochemical and electrochromic colour switching in metal complexes and polymers.
Coverage is extensive and will appeal to a broad readership from chemists and biochemists to engineers and materials scientists. The reviews of established and current interests in the field make this book a key reference for researchers in this exciting and developing area.
Microbial fuel cell (MFC), a bioelectrochemical system, helps to generate electricity at atmospheric temperature conditions with/without existence of inter-mediator using bacteria or microorganism. This technology is very important for future sustainable technology for biodegradable materials using microorganism. In microbial fuel cell, microbes undergo catabolism reaction for easy energy generation. Energy produced is relatively of low intensity due to its nature of mimicking bacterial interactions. However, as per Carnot cycle, efficiency of energy level in MFC is relatively more than 50%. Views on various aspects of MFC will be explained from different resources in terms of their electrochemical performance using their morphology, catalyst arrangement, and activation of microorganism including cathode, anode, and separator along with catalyst. The MFC system assembly consists of a cathode and anode along with biocatalyst which is separated by an ionic porous separator in presence of an electrolyte medium. In real condition, this porous separator is polymeric/ceramic in nature which allows flow of ions thereby electron move in the external circuit. Porous cathode material helps to induce reduction process and anode material undergo oxidation without any external/internal obstruction during operation of MFC will be explained from reported literature. Various factors such as pH, Temperature range, etc. may influence electrochemical redox reaction during MFC working process. This can give a clear idea and simultaneously leads to improvement of the system performance indirectly, which also will be validated from reported documents. Design of MFC module for optimal performance with energy output and other factors influencing MFC performance with application potential will be considered in various aspects. In addition to this, bioenergy harvesting will also be discussed from reported literature.
Producing food by farming and subsequent food manufacturing are central to the world's food supply, accounting for more than half of all production. Production is, however, closely related to the creation of large amounts of organic wastes or byproducts (agro-food waste or wastewater) that negatively impact the environment and the climate. Global climate change mitigation is an urgent need that necessitates sustainable development. For that purpose, proper agro-food waste and wastewater management are essential, not only for waste reduction but also for resource optimization. To achieve sustainability in food production, biotechnology is considered as key factor since its continuous development and broad implementation will potentially benefit ecosystems by turning polluting waste into biodegradable materials; this will become more feasible and common as environmentally friendly industrial processes improve. Bioelectrochemical systems are a revitalized, promising biotechnology integrating microorganisms (or enzymes) with multifaceted applications. The technology can efficiently reduce waste and wastewater while recovering energy and chemicals, taking advantage of their biological elements' specific redox processes. In this review, a consolidated description of agro-food waste and wastewater and its remediation possibilities, using different bioelectrochemical-based systems is presented and discussed together with a critical view of the current and future potential applications.
Microbial fuel cell (MFC) is a promising technology to generate bioelectricity from biomass feedstocks at mild operating temperature and pressure conditions. Despite promising progress in MFC systems, their commercialization has been a major challenge, mainly due to the high cost of components, limited power generation, and lower efficiency. Thus, developing economically viable and environmentally benign electrode and membrane materials that would substantially reduce the manufacturing cost and boost the performance of MFC systems is crucial. Hence, this review aims to highlight the opportunities of using abundantly available waste biomass resources to address the challenges of economic viability and low power productivity of MFC systems. In this stride, the potential of utilization of biomass waste as membrane constituents, electrode materials, and feedstock sources that would enable large-scale commercialization of MFC systems is discussed. Moreover, the study also reviews recent advances in systematic power management and optimization techniques to boost the overall power productivity and efficiency of MFC systems. Based on the comprehensive review made, it is observed that converting biomass waste resources to biochar or activated carbon for direct application as an electrode or electrode coating can decrease its cost by up to 90%. Furthermore, waste biomass-derived biochar can significantly lower the manufacturing costs of the membrane by up to 39 times. The optimum power management configurations are also proposed based on the analysis of the key factors, including the ability to boost low or ultra-low input voltage, the amount of output voltage, and the charging rate. The challenges and limitations of using waste biomass resources in MFC systems are outlined to enlighten future research directions in this domain.
This chapter develops a technological solution for waste management at the source. A device containing a soil microbial fuel cell (MFC) is designed for reliable renewable energy production using kitchen waste. The innovative methodology and constructed green energy conversion system produces ‘eco-friendly’ electricity by capturing energy produced by naturally occurring microbial metabolism of organic materials such as food scraps, manure and plant waste. Biomass that may be used includes municipal solid waste and agricultural by-products. The electricity generated by soil MFCs can be utilized immediately by USB devices. The developed system removes and sequesters carbon dioxide and methane gas, creating a clean, environmentally responsible supply of multiple power types. The overall process provides an option for current power generation and alleviates the need for fossil fuels. Green energy conversion systems enable domestic power generation and create the possibility for reduced dependence on imports for energy needs.KeywordsKitchen organic wasteSoil microbial fuel cellBioelectricity
Microbial fuel cells (MFCs) are an advanced biological, chemo‐electric process for the treatment of wastewater. Exploring this process is economically feasible as it can be used to produce electric energy using bacteria‐mediated electrons through biochemical reactions. Scientists estimate that MFCS have the potential to supply the optimum electricity to urban wastewater treatment plants (WWTPs). A conductive material is used to transfer the substrate from anode to cathode terminals mediated via bacteria. Furthermore, a proton exchange membrane is used to diffuse electrons combined with oxygen in the cathode. A constant release and consumption of energy is optimally required in MFCs. It has been observed that the small MFC when connected in series offer more potential than huge reactors. However, the feasibility of MFCs for use at the domestic level has been efficaciously tested in laboratory experiments, obtaining chemical oxygen demand elimination > 48% and power output approximately 450 mW m −2 . According to recent investigation the MFCs have a great potential to remediate carbon and nitrogen from wastewater. However, the main hindrance with MFCs for use in large setups is that the raw material for constructing MFCs is very costly and has insufficient buffering capacity for the treatment of wastewater. Investigation is ongoing to develop a very effective and efficient design of MFCs to enhance their overall performance.
Understanding the roles of nutrient restriction in extracellular electron transfer (EET) and stability of mixed electroactive biofilm is essential in pollutant degradation and bioenergy production. However, the relevant studies are still limited so far. Herein, the effect of nutrient restriction on the EET pathways and stability of mixed electroactive biofilm was explored. It was found that the electroactive Pseudomonas and Geobacter genera were selectively enriched in the biofilms cultured under total nutrient and P-constrained conditions, and two EET pathways including direct and indirect were found, while Rhodopseudomonas genus was enriched in the N-constrained biofilm, which only had the direct EET pathway. Moreover, multiple analyses including 2D confocal Raman spectra revealed that P-constrained biofilm was rich in extracellular polymeric substances (EPS) especially for polysaccharide, presented a dense and uniform layered distribution, and had better stability than N-constrained biofilm with lower EPS and biofilm with heterostructures cultured under total nutrient conditions.
Microbial fuel cells (MFCs) have undergone great technological development in the last 20 years, but very little has been done to commercialize them. The simultaneous power production and wastewater treatment are features those greatly increase the interest in the use of MFCs. This kind of distributed power generation is renewable and friendly and can be easily integrated into a smart grid. However, there are some key issues with their commercialization: high construction costs, difficulty in developing high power structures, MFC lifespan, and maintaining a high level of efficiency. The objective of this article is to explore the possibilities of using MFCs in urban wastewater not only regarding the technical criteria of their application, but also mainly from an economic point of view, to determine the conditions through which the viability of the investment is ensured and the possibilities of their integration in a smart grid are identified. Initially, this article explores the implementation/configuration of a power plant with MFCs within an urban wastewater treatment plant on a theoretical basis. In addition, based on the corresponding physical quantities for urban wastewater treatment, the construction and operational costs are determined and the viability of the investment is examined based on classic economic criteria such as net present value, benefit–cost ratio, internal rate of return, and discounted payback period. Furthermore, sensitivity analysis is carried out, concerning both technical parameters, such as the percentage of organic matter removal, power density, sewage residence time, MFC efficiency, etc., and economical parameters, such as the reduction of construction costs due to change of materials, change of interest rate, and lifetime. The advantages and disadvantages of their use in smart grids is also analyzed. The results show that the use of MFCs for power generation cannot be utopian as long as they are integrated into the structure of a central wastewater treatment plant on the condition that the scale-up technical issues of MFCs are successfully addressed.
An electrochemical biosensor for remote continuous monitoring of phenolic compounds in environmental analysis is described. The probe relies on rapid and sensitive amperometric detection at a submersible biosensor assembly, connected to a 50 ft long shielded cable. The enzymes laccase and tyrosinase were used as individual sensors and also as a bienzymatic sensor; these enzymes were immobilized chemically on the carbon fiber transducer. The analysis was based on the amperometric detection of the enzymatic products at a potential of −0.10 V vs. Ag/AgCl. Operational conditions were optimized to meet the requirements of remote operations. Tests with untreated river water spiked with phenolic compounds gave results similar to those obtained with synthetic buffer solutions. The remote laccase biosensor allowed the convenient quantification of guaiacol and chloroguaiacol at levels down to 22 and 9 nmol L−1, respectively. The co-immobilization of laccase
and tyrosinase allowed the efficient detection of a larger group of phenolic compounds.
An electrochemical model for a microbial fuel cell process is proposed here. The model was set up on the basis of the experimental results and analysis of biochemical and electrochemical processes. Simulation of the process shows that the model describes the process reasonably well. The analysis of model simulation illustrates how the current output depends on the substrate concentration, mediator concentration and other main variables. The relationship between the current output and over-voltage is revealed from the modelling study.
A feedback thermo-resistive sensor-based measurement scheme was proposed to estimate physical quantities like solar radiation (H), fluid velocity (U) and environment temperature (Ta). It was implemented as an environment temperature meter, using PI controller. Controller implementation was done digitally using FPGA. Practical results are presented.
In many marine environments, a voltage gradient exists across the water sediment interface resulting from sedimentary microbial activity. Here we show that a fuel cell consisting of an anode embedded in marine sediment and a cathode in overlying seawater can use this voltage gradient to generate electrical power in situ. Fuel cells of this design generated sustained power in a boat basin carved into a salt marsh near Tuckerton, New Jersey, and in the Yaquina Bay Estuary near Newport, Oregon. Retrieval and analysis of the Tuckerton fuel cell indicates that power generation results from at least two anode reactions: oxidation of sediment sulfide (a by-product of microbial oxidation of sedimentary organic carbon) and oxidation of sedimentary organic carbon catalyzed by microorganisms colonizing the anode. These results demonstrate in real marine environments a new form of power generation that uses an immense, renewable energy reservoir (sedimentary organic carbon) and has near-immediate application.
Microbial fuel cells (MFCs) have been used to produce electricity from different compounds, including acetate, lactate, and glucose. We demonstrate here that it is also possible to produce electricity in a MFC from domestic wastewater, while atthe same time accomplishing biological wastewater treatment (removal of chemical oxygen demand; COD). Tests were conducted using a single chamber microbial fuel cell (SCMFC) containing eight graphite electrodes (anodes) and a single air cathode. The system was operated under continuous flow conditions with primary clarifier effluent obtained from a local wastewater treatment plant. The prototype SCMFC reactor generated electrical power (maximum of 26 mW m(-2)) while removing up to 80% of the COD of the wastewater. Power output was proportional to the hydraulic retention time over a range of 3-33 h and to the influent wastewater strength over a range of 50-220 mg/L of COD. Current generation was controlled primarily by the efficiency of the cathode. Optimal cathode performance was obtained by allowing passive air flow rather than forced air flow (4.5-5.5 L/min). The Coulombic efficiency of the system, based on COD removal and current generation, was < 12% indicating a substantial fraction of the organic matter was lost without current generation. Bioreactors based on power generation in MFCs may represent a completely new approach to wastewater treatment. If power generation in these systems can be increased, MFC technology may provide a new method to offset wastewater treatment plant operating costs, making advanced wastewater treatment more affordable for both developing and industrialized nations.
Microbial fuel cells hold great promise as a sustainable biotechnological solution to future energy needs. Current efforts to improve the efficiency of such fuel cells are limited by the lack of knowledge about the microbial ecology of these systems. The purposes of this study were (i) to elucidate whether a bacterial community, either suspended or attached to an electrode, can evolve in a microbial fuel cell to bring about higher power output, and (ii) to identify species responsible for the electricity generation. Enrichment by repeated transfer of a bacterial consortium harvested from the anode compartment of a biofuel cell in which glucose was used increased the output from an initial level of 0.6 W m(-2) of electrode surface to a maximal level of 4.31 W m(-2) (664 mV, 30.9 mA) when plain graphite electrodes were used. This result was obtained with an average loading rate of 1 g of glucose liter(-1) day(-1) and corresponded to 81% efficiency for electron transfer from glucose to electricity. Cyclic voltammetry indicated that the enhanced microbial consortium had either membrane-bound or excreted redox components that were not initially detected in the community. Dominant species of the enhanced culture were identified by denaturing gradient gel electrophoresis and culturing. The community consisted mainly of facultative anaerobic bacteria, such as Alcaligenes faecalis and Enterococcus gallinarum, which are capable of hydrogen production. Pseudomonas aeruginosa and other Pseudomonas species were also isolated. For several isolates, electrochemical activity was mainly due to excreted redox mediators, and one of these mediators, pyocyanin produced by P. aeruginosa, could be characterized. Overall, the enrichment procedure, irrespective of whether only attached or suspended bacteria were examined, selected for organisms capable of mediating the electron transfer either by direct bacterial transfer or by excretion of redox components.
Although microbial fuel cells (MFCs) generate much lower power densities than hydrogen fuel cells, the characteristics of the cathode can also substantially affect electricity generation. Cathodes used for MFCs are often either Pt-coated carbon electrodes immersed in water that use dissolved oxygen as the electron acceptor or they are plain carbon electrodes in a ferricyanide solution. The characteristics and performance of these two cathodes were compared using a two-chambered MFC. Power generation using the Pt-carbon cathode and dissolved oxygen (saturated) reached a maximum of 0.097 mW within 120 h after inoculation (wastewater sludge and 20 mM acetate) when the cathode was equal size to the anode (2.5 x 4.5 cm). Once stable power was generated after replacing the MFC with fresh medium (no sludge), the Coulombic efficiency ranged from 63 to 78%. Power was proportional to the dissolved oxygen concentration in a manner consistent with Monod-type kinetics, with a half saturation constant of K(DO) = 1.74 mg of O2/L. Power increased by 24% when the cathode surface areas were increased from 22.5 to 67.5 cm2 and decreased by 56% when the cathode surface area was reduced to 5.8 cm2. Power was also substantially reduced (by 78% to 0.02 mW) if Pt was not used on the cathode. By using ferricyanide instead of dissolved oxygen, the maximum power increased by 50-80% versus that obtained with dissolved oxygen. This result was primarily due to increased mass transfer efficiencies and the larger cathode potential (332 mV) of ferricyanide than that obtained with dissolved oxygen (268 mV). A cathode potential of 804 mV (NHE basis) is theoretically possible using dissolved oxygen, indicating that further improvements in cathode performance with oxygen as the electron acceptor are possible that could lead to increased power densities in this type of MFC.
Electrochemical energy production is drawing interest as an alternative energy/power source. Critical to the success of this source is for the design to be more sustainable and more environmental friendly. Systems for electrochemical energy storage and conversion include batteries, fuel cells, and electrochemical capacitors (ECs). All are based on the fundamentals of electrochemical thermodynamics and kinetics. All three are needed to service the wide energy requirements of various devices and systems.
A remote electrochemical biosensor for field monitoring of organophosphate nerve agents is described. The new sensor relies on the coupling of the effective biocatalytic action of organophosphorus hydrolase (OPH) with a submersible amperometric probe design. This combination results in a fast, sensitive, selective, and stable response at large sample-instrument distances. Such attractive performance is illustrated for direct measurements of micromolar levels of paraoxon and methyl parathion in untreated river water samples. Unlike multi-step inhibition biosensors, the remote OPH probe offers single-step direct measurements, and is thus highly suitable for the continuous monitoring task. Variables relevant to field operations are discussed, along with prospects for remote monitoring and early detection of nerve agents.
The open-circuit potential (OCP) values of Type 316L (UNS S31603) stainless steel and Ti-6Al-4V (UNS R56400) corrosion coupons, exposed to fresh river water, were ennobled to as high as 365 mV vs saturated calomel electrode (SCE) and 400 mV SCE, respectively. With microchemical imaging capabilities and high-detection sensitivity, a surface analysis technique based on time-of-flight secondary ion mass spectroscopy (ToF-SIMS) was developed to identify the oxidation states and distribution of biominerals on the ennobled metal surfaces. ToF-SIMS spectra of the microbial deposits com-
pared to spectra of different manganese and iron mineral standards indicated that the biominerals on the metal surfaces are a mixture of ferric oxide (Fe2O3), manganese oxide
(Mn3O4), and manganese oxyhydroxide (MnOOH) on fully ennobled coupons, and a mixture of iron oxide (Fe3O4), Fe2O3, Mn3O4, and manganese(III) oxide (Mn2O3) on partially ennobled coupons. Biomineralized manganese and iron oxides on the Type 316L stainless steel surfaces, regardless of the oxidation states, endanger the material integrity in a similar manner, as evidenced by the elevated OCP and increased
cathodic current density upon mild polarization.
Ennobled open-circuit potential (E{sub corr}) for type 316L stainless steel (SS [UNS S31603]) exposed to fresh river water was investigated using microelectrodes to measure dissolved oxygen (DO), hydrogen peroxide (HâOâ), and local E{sub corr} within biofouling deposits. Galvanostatic techniques were used to measure capacitance (C) and to titrate reducible surface material. Results indicated deposits were uniformly aerobic and did not contain elevated levels of cathodic depolarizers. Development of ennobled potential was related to E{sub corr} near the beginning of exposure and occurred on surfaces with as little as 3% to 5% biofouling coverage. Galvanostatic measurements revealed a strong correlation between C and E{sub corr} as E{sub corr} increased during biofouling. Galvanostatic reduction measurements indicated increased abundance of reducible surface-bound material during the same period. Results suggested an ennoblement mechanism involving modifications of the metal oxide surface.
The increase in the open circuit potential of passive metals in natural waters due to biofilm formation at the metal surface, termed ennoblement, has been reported for nearly 30 years. Although its occurrence is undoubtedly associated with microbial colonization, the underlying mechanism of ennoblement remains controversial. Recent work produced in the authors’ laboratory has provided convincing experimental evidence that ennoblement can be caused by deposition of biomineralized manganese produced by manganese‐oxidizing biofilms. The purpose of this study was to determine the effects of environmental factors on the rate and extent of ennoblement of 316L stainless steel exposed to natural waters. This was accomplished by exposing corrosion coupons to four freshwater systems over a 4‐yearperiod. The rate and extent of ennoblement observed in these locations was correlated with dissolved manganese concentrations, the mass of accumulated manganese oxides, organic carbon concentration, dissolved oxygen concentration, flow, conditions, temperature, and pH in these environments.
A newly designed remote probe has been developed for stripping measurements of trace mercury at large sample-instrument distances. Various gold electrodes, stripping modes, and operation conditions have been optimized to meet the requirement of remote monitoring of mercury. The favorable stripping potentiometric response obtained following 0.5–1.0 min deposition, leads to a rapid detection of low ppb mercury concentrations, and offers a fast warning capability. The optimized protocol offers a low detection limit ( of 0.3/mu;g/L with 5 min deposition) and good precision (RSD of 3.9 % for n = 100). Due to its inherent sensitivity, simplicity, stability, and smaller dimensions the new probe is well suited for in situ monitoring of trace mercury in natural waters.
An electrochemical flow system for on-line monitoring of trace 2,4,6-trinitrotoluene (TNT) in marine environments, based on a square-wave voltammetric operation at a carbon-fiber based detector, is described. The system offers selective measurements of sub-ppm concentrations of TNT in untreated seawater matrix (with a detection limit of 25ppb). It responds rapidly to sudden changes in the TNT concentration with no observable carry-over. About 600 runs can be made every hour with high reproducibility (e.g. R.S.D.=2.3%, n=40) and stability. A computerized baseline subtraction offers effective compensation of the oxygen background contribution. Good sensitivity and stability is illustrated also for on-line monitoring of TNT in untreated river water samples. The system lends itself to full automation and to deployment onto various mobile platforms. By meeting the high-sensitivity, selectivity, stability, portability and low-cost demands, such as voltammetric flow detection holds great promise for field-based screening operations aimed at characterizing and remediating unexploded ordnance (UXO) contaminated underwater sites.
The performance of a remote stripping sensor based on mercury microelectrodes (MM-RS) for the in situ detection of trace metals in aquatic systems, was investigated. The submersible device employed here consists of a single mercury-coated platinum disk microelectrode assembled in a two-electrode cell configuration, and connected remotely by a 30 m long shielded cable. First, the MM-RS device is characterized in Ru(NH3) and Pb2+ synthetic aqueous solutions by applying cyclic voltammetry and anodic stripping voltammetry (ASV), respectively. The results obtained show that the small electrode dimensions and the related low currents involved, the long remote connection cable or the use of a two-electrode system do not cause noise effects or uncompensated resistance problems in the measurements. Using square-wave voltammetry in the stripping step, linear calibration graphs for Pb2+ ions over the concentration range 1×10−9−5×10−7 M were obtained, and a detection limit, DL, of 0.15 nM was found. The relative standard deviation (RSD), at 5×10−8 M Pb2+ level, was within 5%. The effect of humic acid and of sodium dodecylsulfate surfactants on the stripping responses was also investigated. The performance of the submersible MM-RS system was tested for the in situ monitoring of the labile fraction of lead and copper on a site of the Lagoon of Venice. In situ Pb2+ and Cu2+ concentrations were monitored for about 8 hours, by leaving the sensor immersed in the lagoon waters (2 m depth) and recording the response every hour. Under these field conditions, reliable in situ data for the labile fraction of these metal ions with a satisfactory precision, the RSD being within 7 and 9 % for lead and copper, respectively, were obtained.
Electrochemical reduction of dioxygen to water proceeds very effectively at 0.4 V versus Ag ∣ AgCl in pH 7.0 solution at an ambient temperature through the 2,2′-azinobis (3-ethylbenzothiazoline-6-sulfonate) (ABTS2−)-mediated and bilirubin oxidase (BOD) [EC 1.3.3.5]-catalyzed reaction of dioxygen. Electrochemistry of the ABTS2− oxidation and the indirect catalytic reduction of dioxygen with ABTS2− and BOD have been studied in detail to elucidate fully the bioelectrocatalytic behavior. The bioelectrocatalytic system using a carbon felt electrode has been examined and discussed in view of the cathode reaction in a biofuel cell.
The growth kinetics of the sulfate-reducing bacteria Desulfovibrio desulfuricans Essex 6 was investigated under various conditions for potential use in a microbial fuel cell that recovers electrons generated from the reduction of sulfate to hydrogen sulfide. Hydrogen sulfide was found to inhibit growth and decrease both the growth yields and the sulfate-specific reduction rate. Hydrogen sulfide inhibition was direct, reversible, and not due to limitation by iron deficiency. A high initial lactate concentration also retarded bacterial growth, reduced the specific sulfate reduction rates, and gave variable biomass growth yields. This effect resulted from a bottleneck in the lactate oxidation pathway which induced the production of the secondary product butanol. The use of pyruvate as a carbon source was more advantageous than lactate in terms of growth rate and biomass growth yields, with only a slight decrease in the rate of specific sulfate reduction. For equal biomass, a slightly higher current density was generated from lactate than pyruvate, but pyruvate required nearly 40% less sulfate.
Twenty-three 316L stainless steel (SS) coupons were exposed in situ to fresh river-water for periods of up to 35 days. All samples developed steady-state corrosion potentials (Ecorr) near + 350 mV (SCE) and polarization measurements showed enhanced cathodic current density characteristic of passive metal ennoblement. Epifluorescence and scanning electron microscopy of the attached biofilm showed numerous 10–20μm diameter Mn-rich annular deposits, associated clusters of bacterial cells, and abundant sheathed bacteria. Dissolution of the Mn deposits using Na2SO3 shifted Ecorr to pre-exposure values. SS coated with MnO2 paste displayed electrochemical behavior nearly identical to that of ennobled samples. A mechanism of ennoblement by MnO2 biofouling is proposed which explains a variety of findings on the electrochemical behavior of microbially colonized SS.
Pitting corrosion of 316L stainless steel ennobled in the presence of manganese-oxidizing bacteria, Leptothrix discophora, was studied in a low-concentration sodium chloride solution. Corrosion coupons were first exposed to the microorganisms in a batch reactor until ennoblement occurred, then sodium chloride was added, which initiated pitting. The pits had aspect ratios (length divided by width) and shapes closely resembling the aspect ratio and the shape of the bacteria, which suggested that the microorganisms were involved in pit initiation.
This article describes three recent developments from our laboratory, in which screen-printed carbon electrodes have been modified in order to develop sensors/biosensors for analytes of biomedical importance. The analytical applications described are (i) progesterone, (ii) glucose and (iii) haemoglobin determination. For each application, the modification procedure for the base transducer and the sensor/biosensor performance characteristics are described. The potential biomedical application areas for these devices are discussed.
Manganese- and iron-oxidizing bacteria (MFOB) are widely implicated in microbially influenced corrosion, often in association with sulfate-reducing bacteria (SRB). Traditionally MFOB have been assigned a passive role in the corrosion process, promoting differential aeration cells, and providing oxygen depleted conditions conducive to the growth and corrosive attack of SRB. Recent work, summarized in this article, demonstrates that manganese biofouling alters the electrochemical behavior of stainless steel (SS), and suggests that MFOB are more active in localized corrosion than traditionally held. The paper discusses the chemistry and potentially corrosive impact of manganese and iron oxides on SS, explores the possible relationship between MFOB and SRB, and proposes a model to describe the synergistic influence these organisms may exert in the corrosion process.
With the rapid development of micro total analysis systems and sensitive biosensing technologies, it is often desirable to immobilize biomolecules to small areas of surfaces other than silicon. To this end, photolithographic techniques were used to derivatize micrometer-sized, spatially segregated biosensing elements on several different substrate surfaces. Both an interference pattern and a dynamic confocal patterning apparatus were used to control the dimensions and positions of immobilized regions. In both of these methods, a UV laser was used to initiate attachment of a photoactive biotin molecule to the substrate surfaces. Once biotin was attached to a substrate, biotin/avidin/biotin chemistry was used to attach fluorescently labeled or nonlabeled avidin and biotinylated sensing elements such as biotinylated antibodies. Dimensions of 2-10 microm were achievable with these methods. A wide variety of materials, including glassy carbon, quartz, acrylic, polystyrene, acetonitrile-butadiene-styrene, polycarbonate, and poly(dimethylsiloxane), were used as substrates. Nitrene- and carbene-generating photolinkers were investigated to achieve the most homogeneous films. These techniques were applied to create a prototype microfluidic sensor device that was used to separate fluorescently labeled secondary antibodies.
Mediator-coupled microbial fuel cells containing Proteus vulgaris were constructed and the cell performance was tested. Fuel cell efficiency depended on the carbon source in the initial medium of the microorganism. Maltose and trehalose were not utilized substantially by P. vulgaris; however, their presence in the initial medium resulted in enhanced cell performance. In particular, galactose showed 63% coulombic efficiency in a biofuel cell after P. vulgaris was cultured in a trehalose-containing medium. This work demonstrates that optimum utilization of carbon sources by microorganisms, which leads to the maximization of fuel cell performance, is possible simply by adjusting initial carbon sources.
Pairs of platinum mesh or graphite fiber-based electrodes, one embedded in marine sediment (anode), the other in proximal seawater (cathode), have been used to harvest low-level power from natural, microbe established, voltage gradients at marine sediment-seawater interfaces in laboratory aquaria. The sustained power harvested thus far has been on the order of 0.01 W/m2 of electrode geometric area but is dependent on electrode design, sediment composition, and temperature. It is proposed that the sediment/anode-seawater/cathode configuration constitutes a microbial fuel cell in which power results from the net oxidation of sediment organic matter by dissolved seawater oxygen. Considering typical sediment organic carbon contents, typical fluxes of additional reduced carbon by sedimentation to sea floors < 1,000 m deep, and the proven viability of dissolved seawater oxygen as an oxidant for power generation by seawater batteries, it is calculated that optimized power supplies based on the phenomenon demonstrated here could power oceanographic instruments deployed for routine long-term monitoring operations in the coastal ocean.
The production of electricity by Shewanella putrefaciens in the absence of exogenous electron acceptors was examined in a single compartment fuel cell with different types of electrodes and varying physiological conditions. Electricity production was dependent on anode composition, electron donor type and cell concentration. A maximum current of 2.5 mA and a current density of 10.2 mW/m(2)electrode was obtained with a Mn(4+) graphite anode, 200 mM sodium lactate and a cell concentration of 3.9 g cell protein/ml. Current production by S. putrefaciens was enhanced 10-fold when an electron mediator (i.e., Mn(4+) or neutral red) was incorporated into the graphite anode.
Microbially powered fuel cells tap into an abundant ecosystem
energy circuit.
We have operated a microbial fuel cell in which glucose was oxidized by Klebsiella pneumoniae in the anodic compartment, and biomineralized manganese oxides, deposited by Leptothrix discophora, were electrochemically reduced in the cathodic compartment. In the anodic compartment, to facilitate the electron transfer from glucose to the graphite electrode, we added a redox mediator, 2-hydroxy-1,4-naphthoquinone. We did not add any redox mediator to the cathodic compartment because the biomineralized manganese oxides were deposited on the surface of a graphite electrode and were reduced directly by electrons from the electrode. We have demonstrated that biomineralized manganese oxides are superiorto oxygen when used as cathodic reactants in microbial fuel cells. The current density delivered by using biomineralized manganese oxides as the cathodic reactant was almost 2 orders of magnitude higher than that delivered using oxygen. Several fuel cells were operated for 500 h, reaching anodic potentials of -441.5 +/- 31 mVscE and cathodic potentials of +384.5 +/- 64 mVscE. When the electrodes were connected by a 50 Ohms resistor, the fuel cell delivered the peak power density of 126.7 +/- 31.5 mW/m2.
Brodd What Are Batteries, Fuel Cells, and Supercapacitors? Received for review December 7
- M Winter
Winter, M.; Brodd What Are Batteries, Fuel Cells, and Supercapacitors? Chem. Rev. 2004, 104, 4245-4269. Received for review December 7, 2004. Revised manuscript received May 5, 2005. Accepted May 10, 2005. ES0480668
Productionofelectricity duringwastewatertreatmentusingasinglechambermicrobial fuel cell
- H Liu
- R Ramnarayanan
- B E Logan
Liu,H.;Ramnarayanan,R.;Logan,B.E.Productionofelectricity duringwastewatertreatmentusingasinglechambermicrobial fuel cell. Environ. Sci. Technol. 2004, 38(7), 2281-2285.
Harvesting energyfromthemarinesediment-waterinterface
- C E Reimers
- L M Tender
- S Fertig
- W Wang
Reimers, C. E.; Tender, L. M.; Fertig, S.; Wang, W. Harvesting energyfromthemarinesediment-waterinterface.Environ.Sci. Technol. 2001, 35(1), 192-195.
Willner, I. Biochemical fuel cells. In Handbook of Fuel Cells-Fundamentals, Technology and Ap-plications
- E Katz
- A N Shipway
Katz, E.; Shipway, A. N.; Willner, I. Biochemical fuel cells. In Handbook of Fuel Cells-Fundamentals, Technology and Ap-plications;
Physiologic studies with the sulfate-reducing bacterium Desulfovibrio desulfuricans: Evaluation for use in a biofuel cell
- M J Cooney
- E Roschi
- I W Marison
- C Comninellis
- U Vonstockar
Cooney, M. J.; Roschi, E.; Marison, I. W.; Comninellis, C.;
vonStockar, U. Physiologic studies with the sulfate-reducing
bacterium Desulfovibrio desulfuricans: Evaluation for use in
a biofuel cell. Enzyme Microb. Technol. 1996, 18(5), 358-365.
Brodd What Are Batteries, Fuel Cells, and Supercapacitors?
(28) Winter, M.; Brodd What Are Batteries, Fuel Cells, and Supercapacitors? Chem. Rev. 2004, 104, 4245-4269.
- Wang J.