Monitoring and quantification of bioelectrochemical biofilms by means of OCT in novel and customized reactor-setups

2020 ◽  
Author(s):  
Max Hackbarth ◽  
Tobias Jung ◽  
Johannes Eberhard Reiner ◽  
Andrea Hille-Reichel ◽  
Michael Wagner ◽  
...  
Keyword(s):  
Current Density ◽  
Microbial Fuel Cells ◽  
Cathode Surface ◽  
Value Added ◽  
Limiting Factor ◽  
Physical Parameters ◽  
Turnover Rates ◽  
Microbial Electrosynthesis ◽  
Measured Current ◽  
Biofilm Development

<p>In the last 40 years, bioelectrochemical systems (BESs) have been increasingly discussed within the scope of debates about sustainable energy sources and production of value added chemicals independent of fossil sources. Since the produced current in microbial fuel cells as well as the turnover rates in microbial electrosynthesis cells are dependent on the biocatalysts´ activity, control of the growing biofilm plays a major role in BESs. Moreover, the knowledge about the interplay between biofilm development and electrochemical parameters is crucial for optimizing these sytems.</p> <p>In the last 3 years, various electroactive biofilms (anodic and cathodic) were cultivated and characterized in a versatile and house made lab-scale flow cell system as well as in a rotating disc biofilm contactor (RDBC). Both systems allow for control of substrate (liquid and gaseous), and nutritional conditions as well as hydrodynamics and other physical parameters. The monitoring of biofilm development was conducted non-invasively by means of optical coherence tomography (OCT). For cathodic biofilms, quantitative analysis of generated 3D OCT data sets revealed a correlation between substratum coverage and measured current density. The increase of substratum coverage led to a decrease of measured current density due to less abiotic redox processes on the cathode surface. A stable current density was achieved when a substratum coverage of 99 % was reached. Furthermore, calculated biofilm accumulation rates could also be correlated with the substratum coverage. The overall biofilm accumulation rate decreased when the substratum was fully covered. Both correlations support the hypothesis that the availability of electrons from the cathode surface is a limiting factor in microbial electrosynthesis.</p> <p>A 10-liter RDBC was designed to continuously harvest biomass from the electrode to extract intracellularly stored products. In future, this approach could be applied for biotechnological processes. Additionally, the RDBC can be used to obtain reliable mass balances and turnover rates because of its larger scale.</p>

An enriched electroactive homoacetogenic biocathode for the microbial electrosynthesis of acetate through carbon dioxide reduction

2015 ◽  
Vol 183 ◽  
pp. 445-462 ◽  
Author(s):  
Gunda Mohanakrishna ◽  
Jai Sankar Seelam ◽  
Karolien Vanbroekhoven ◽  
Deepak Pant
Keyword(s):  
Carbon Dioxide ◽  
Production Rate ◽  
Electrode Material ◽  
Coulombic Efficiency ◽  
Value Added ◽  
Microbial Electrosynthesis ◽  
Metal Support ◽  
Electrode Combination ◽  
Biofilm Development ◽  
Graphite Rod

In the direction of generating value added chemicals from carbon dioxide (CO2) reduction through microbial electrosynthesis (MES), considering the crucial impact of the electrode material for the biofilm development and electron delivery, an attempt was made in this study to evaluate the efficiency of two different materials as biocathodes and their respective output in terms of electrosynthesis. The electrode material is a key component in the MES process. Several electrodes such as platinum, graphite foil, dimentionally stable anode (DSA) and graphite rod, and VITO-CoRE™ derived electrodes were tested for their suitability for ideal electrode combination in a three electrode cell setup. Bicarbonates (the dissolved form of CO2) was reduced to acetate by a selectively developed biocathode under a mild applied cathodic potential of −400 mV (vs.SHE) in 500 mL of single chamber MES cells operating for more than four months. Among the two electrode combinations evaluated, VITO-CoRE™-PL (VC-IS, plastic inert support) as the cathode and VITO-CoRE™-SS (VC-SS, stainless steel metal support) as the counter electrode showed higher production (4127 mg L−1) with a volumetric production rate of 0.569 kg per m3per d than the graphite rod (1523 mg L−1) with a volumetric production rate of 0.206 kg per m3per d. Contrary to the production efficiencies, the coulombic efficiency was higher with the second electrode combination (40.43%) than the first electrode combination (29.91%). Carbon conversion efficiency to acetate was higher for VC-IS (90.6%) than the graphite rod (82.0%).

scholarly journals Valorisation of CO2 into Value-Added Products via Microbial Electrosynthesis (MES) and Electro-Fermentation Technology

Fermentation ◽  
2021 ◽  
Vol 7 (4) ◽  
pp. 291
Author(s):  
Marzuqa Quraishi ◽  
Kayinath Wani ◽  
Soumya Pandit ◽  
Piyush Kumar Gupta ◽  
Ashutosh Kumar Rai ◽  
...  
Keyword(s):  
Microbial Fuel Cells ◽  
Harmful Effect ◽  
Value Added ◽  
Electrical Energy ◽  
High Energy ◽  
High Energy Density ◽  
Microbial Electrosynthesis ◽  
Microbial Electrolysis Cells ◽  
Inorganic Matter ◽  
Microbial Electrocatalysis

Microbial electrocatalysis reckons on microbes as catalysts for reactions occurring at electrodes. Microbial fuel cells and microbial electrolysis cells are well-known in this context; both prefer the oxidation of organic and inorganic matter for producing electricity. Notably, the synthesis of high energy-density chemicals (fuels) or their precursors by microorganisms using bio-cathode to yield electrical energy is called Microbial Electrosynthesis (MES), giving an exceptionally appealing novel way for producing beneficial products from electricity and wastewater. This review accentuates the concept, importance and opportunities of MES, as an emerging discipline at the nexus of microbiology and electrochemistry. Production of organic compounds from MES is considered as an effective technique for the generation of various beneficial reduced end-products (like acetate and butyrate) as well as in reducing the load of CO2 from the atmosphere to mitigate the harmful effect of greenhouse gases in global warming. Although MES is still an emerging technology, this method is not thoroughly known. The authors have focused on MES, as it is the next transformative, viable alternative technology to decrease the repercussions of surplus carbon dioxide in the environment along with conserving energy.

RESTORATION OF MACHINE PARTS WITH GALVANIZED ZINC COATINGS

2020 ◽  
Vol 4 (141) ◽  
pp. 140-147
Author(s):  
MIKHAIL VIKHAREV ◽  
◽  
VLADIMIR YUDIN ◽  
VESELOVSKIY NIKOLAY ◽  
◽  
...  
Keyword(s):  
Current Density ◽  
Cathode Surface ◽  
Zinc Coating ◽  
Cathode Current Density ◽  
Research Purpose ◽  
Cathode Layer ◽  
Properties Of Coatings ◽  
Chemical Polarization ◽  
Cathode Current ◽  
Zinc Coatings

The article shows the role of electroplating in the restoration of parts, indicates the advantages of restoring parts with electroplating over other methods, and gives the characteristics and properties of coatings obtained by electroplating. (Research purpose) The research purpose is in increasing the speed of application of zinc electroplating when restoring parts. (Materials and methods) The cathode current density has a decisive influence on the coating speed. The main reason for limiting the cathode current density during galvanizing from sulfuric acid electrolytes is the chemical polarization of the cathode. The article presents a study on the designed installation for the application of galvanic coatings. When applying coatings to the internal surfaces of parts, there was used a device with activating elements having an electromechanical rotation drive. This device prevents depletion of the near-cathode layer of the electrolyte and reduces the chemical polarization of the cathode. Elements made of moisture-resistant skin were used as activators. (Results and discussion) The article presents the results of experiments as a dependence of the coating speed on the speed of the activator relative to the restoring surface. It also presents the relationship between the size of the abrasive grains of the activating elements, the force of their pressing against the cathode surface, the speed of movement of the activator and the speed of applying the zinc coating, as well as its quality. By activating the cathode surface, it was possible to raise the operating current density to 100-150 amperes per square decimeter. The speed of application of zinc coatings is 16-25 micrometers per minute. (Conclusions) In the course of research, authors determined the conditions of electrolysis during galvanizing, which provide a significant increase in the cathode current density and the rate of application of these coatings during the restoration of parts.

scholarly journals Cellulose Derived Graphene/Polyaniline Nanocomposite Anode for Energy Generation and Bioremediation of Toxic Metals via Benthic Microbial Fuel Cells

Polymers ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 135
Author(s):  
Asim Ali Yaqoob ◽  
Mohamad Nasir Mohamad Ibrahim ◽  
Khalid Umar ◽  
Showkat Ahmad Bhawani ◽  
Anish Khan ◽  
...  
Keyword(s):  
Fuel Cells ◽  
Current Density ◽  
Toxic Metals ◽  
Microbial Fuel Cells ◽  
Organic Substrate ◽  
Synthetic Wastewater ◽  
Multiple Parameters ◽  
Pani Composite ◽  
Industrial Level ◽  
Modified Graphene

Benthic microbial fuel cells (BMFCs) are considered to be one of the eco-friendly bioelectrochemical cell approaches nowadays. The utilization of waste materials in BMFCs is to generate energy and concurrently bioremediate the toxic metals from synthetic wastewater, which is an ideal approach. The use of novel electrode material and natural organic waste material as substrates can minimize the present challenges of the BMFCs. The present study is focused on cellulosic derived graphene-polyaniline (GO-PANI) composite anode fabrication in order to improve the electron transfer rate. Several electrochemical and physicochemical techniques are used to characterize the performance of anodes in BMFCs. The maximum current density during polarization behavior was found to be 87.71 mA/m2 in the presence of the GO-PANI anode with sweet potato as an organic substrate in BMFCs, while the GO-PANI offered 15.13 mA/m2 current density under the close circuit conditions in the presence of 1000 Ω external resistance. The modified graphene anode showed four times higher performance than the unmodified anode. Similarly, the remediation efficiency of GO-PANI was 65.51% for Cd (II) and 60.33% for Pb (II), which is also higher than the unmodified graphene anode. Furthermore, multiple parameters (pH, temperature, organic substrate) were optimized to validate the efficiency of the fabricated anode in different environmental atmospheres via BMFCs. In order to ensure the practice of BMFCs at industrial level, some present challenges and future perspectives are also considered briefly.

scholarly journals Electrochemical Characterization of Low-Temperature Direct Ethanol Fuel Cells Using Direct and Alternate Current Methods

2019 ◽  
Author(s):  
Paweł Wnuk ◽  
Rafal Jurczakowski ◽  
Adam Lewera
Keyword(s):  
Low Temperature ◽  
Current Density ◽  
Ethanol Concentration ◽  
Physical Parameters ◽  
Impedance Spectra ◽  
Ethanol Fuel ◽  
Cell Temperature ◽  
Faradaic Impedance ◽  
Cell Impedance

Here we report for the first time the results of systematic characterization of a low-temperature polymer electrolyte membrane direct ethanol fuel cell using DC and AC electrochemical methods. Model catalysts (carbon supported Pt nanoparticles) painted on carbon paper are used as anode and cathode. Influence of physical parameters, such as cell temperature, current density, ethanol concentration and anode fuel flow rate on overall cell impedance is studied. Analysis of the obtained impedance spectra in connection with DC measurements allows us to comment on cell properties and to separate different contributions to the overall cell polarization. Our results suggest that the cell impedance is dominated by anode faradaic impedance, with negligible contribution from cathode faradaic impedance. The anode impedance depends strongly on current density and cell temperature, but is not significantly influenced by ethanol concentration. Presence of anode mass-transfer impedance, even when ethanol was fed to the cell in high excess, is confirmed. Based on the results we conclude that changes in ethanol electro-oxidation mechanism might manifest themselves on the impedance spectra in the low-frequency inductive loop. Nonetheless, further studies involving equivalent circuit modelling are needed to determine the exact influence of the cell parameters on the anode kinetics.

scholarly journals APLIKASI SIG UNTUK PENETAPAN KESESUAIAN WILAYAH PENERAPAN MEKANISASI PERTANIAN TANAMAN PANGAN

2016 ◽  
Vol 10 (1) ◽  
pp. 31
Author(s):  
Mubekti Mubekti
Keyword(s):  
Remote Sensing ◽  
Limiting Factors ◽  
Limiting Factor ◽  
Physical Parameters ◽  
Know How ◽  
Agricultural Mechanization ◽  
Preliminary Research

The study is the preliminary research aiming to apply the usefulness of the GISsystem for classifying suitability of region to the agricultural mechanization. Simplebasic theory of GIS and classification of agricultural mechanization were presented.Nine physical and non-physical parameters as limiting factors were defined and aweight of each parameter was calculated in order to know how far its effect to theagricultural mechanization practice. Data coming from several types, ie: numeric,vector and remote sensing (raster) were prepared to support the process. Twoordoes consisting of five classes were employed to extract suitability classificationof each District in Jawa Barat dan Banten Province. The results show that tendistricts are classified into suitable for applying agricultural mechanization, and therest ten districts are classified into not suitable. Depending on the dynamic characterof limiting factor, suitability class would possibly change along the time. Saveralconclusions and advices for improving research are given.

CATHODE SURFACE CHANGES IN THE PRESENCE OF GELATIN DURING ELECTRODEPOSITION OF COPPER

1943 ◽  
Vol 21b (6) ◽  
pp. 125-132 ◽  
Author(s):  
W. Gauvin ◽  
C. A. Winkler
Keyword(s):  
Grain Size ◽  
Current Density ◽  
Copper Sulphate ◽  
Cathode Surface ◽  
Active Area ◽  
Cathode Polarization ◽  
Active Centres ◽  
Main Factor ◽  
Surface Changes

Measurements of the cathode polarization during electrodeposition of copper from acid copper sulphate solutions indicate that introduction of gelatin into the electrolyte decreases the area of the cathode available for deposition, or active area, owing to adsorption of gelatin on the active centres. This decrease in area causes an increase in the true current density, with a resulting increase in cathode polarization, the former being assumed the main factor in causing an increase in the rate of nuclear formation and decrease in grain size.

scholarly journals Utilization of Second Order Slip, Activation Energy and Viscous Dissipation Consequences in Thermally Developed Flow of Third Grade Nanofluid with Gyrotactic Microorganisms

Symmetry ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 309 ◽  
Author(s):  
Zahra Abdelmalek ◽  
Sami Ullah Khan ◽  
Hassan Waqas ◽  
Hossam A. Nabwey ◽  
Iskander Tlili
Keyword(s):  
Activation Energy ◽  
Viscous Dissipation ◽  
Microbial Fuel Cells ◽  
Liquid Metals ◽  
Second Order ◽  
Transformer Oil ◽  
Third Grade ◽  
Physical Parameters ◽  
Gyrotactic Microorganisms ◽  
Motion Features

In recent decades, an interest has been developed towards the thermal consequences of nanofluid because of utilization of nano-materials to improve the thermal conductivity of traditional liquid and subsequently enhance the heat transportation phenomenon. Following this primarily concept, this current work investigates the thermal developed flow of third-grade nanofluid configured by a stretched surface with additional features of activation energy, viscous dissipation and second-order slip. Buongiorno’s nanofluid model is used to explore the thermophoresis and Brownian motion features based on symmetry fundamentals. It is further assumed that the nanoparticles contain gyrotactic microorganisms, which are associated with the most fascination bioconvection phenomenon. The flow problem owing to the partial differential equations is renovated into dimensional form, which is numerically simulated with the help of bvp4c, by using MATLAB software. The aspects of various physical parameters associated to the current analysis are graphically examined against nanoparticles’ velocity, temperature, concentration and gyrotactic microorganisms’ density distributions. Further, the objective of local Nusselt number, local Sherwood number and motile density number are achieved numerically with variation of various parameters. The results presented here may find valuable engineering applications, like cooling liquid metals, solar systems, power production, solar energy, thermal extrusion systems cooling of machine equipment, transformer oil and microelectronics. Further, flow of nanoparticles containing gyrotactic microorganisms has interesting applications in microbial fuel cells, microfluidic devices, bio-technology and enzyme biosensors.

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