scholarly journals Modeling Power Generation and Energy Efficiencies in Air-Cathode Microbial Fuel Cells Based on Freter Equations

2018 ◽  
Vol 8 (10) ◽  
pp. 1983 ◽  
Author(s):  
Hongjian Lin ◽  
Sarah Wu ◽  
Jun Zhu
Keyword(s):  
Power Generation ◽  
Energy Efficiency ◽  
Dilution Rate ◽  
Microbial Fuel Cells ◽  
Substrate Concentration ◽  
Internal Resistance ◽  
Initial Substrate ◽  
External Resistor ◽  
Attached Biomass ◽  
Initial Substrate Concentration

The model proposed in this study was based on the assumption that the biomass attached to the anode served as biocatalysts for microbial fuel cell (MFC) exoelectrogenesis, and this catalytic effect was quantified by the exchange current density of anode. By modifying the Freter model and combining it with the Butler–Volmer equation, this model could adequately describe the processes of electricity generation, substrate utilization, and the suspended and attached biomass concentrations, at both batch and continuous operating modes. MFC performance is affected by the operating variables such as initial substrate concentration, external resistor, influent substrate concentration, and dilution rate, and these variables were revealed to have complex interactions by data simulation. The external power generation and energy efficiency were considered as indices for MFC performance. The simulated results explained that an intermediate initial substrate concentration (about 100 mg/L under this reactor configuration) needed to be chosen to achieve maximum overall energy efficiency from substrate in the batch mode. An external resistor with the value approximately that of the internal resistance, boosted the power generation, and a resistor with several times of that of the internal resistance achieved better overall energy efficiency. At continuous mode, dilution rate significantly impacted the steady-state substrate concentration level (thus substrate removal efficiency and rate), and attached biomass could be fully developed when the influent substrate concentration was equal to or higher than 100 mg/L at any dilution rate of the tested range. Overall, this relatively simple model provided a convenient way for evaluating and optimizing the performance of MFC reactors by regulating operating parameters.

scholarly journals Modeling Power Generation and Energy Efficiencies in Air-Cathode Microbial Fuel Cells Based on Freter Equations

2018 ◽  
Author(s):  
Hongjian Lin ◽  
Sarah (Xiao) Wu ◽  
Jun Zhu
Keyword(s):  
Power Generation ◽  
Energy Efficiency ◽  
Dilution Rate ◽  
Microbial Fuel Cells ◽  
Substrate Concentration ◽  
Internal Resistance ◽  
Initial Substrate ◽  
External Resistor ◽  
Attached Biomass ◽  
Initial Substrate Concentration

The model proposed in this study was based on the assumption that the biomass attached to the anode served as biocatalysts for MFC exoelectrogenesis, and this catalytic effect was quantified by the exchange current density of anode. By modifying the Freter model and combining it with the Butler-Volmer equation, this model could adequately describe the processes of electricity generation, substrate utilization, and the suspended and attached biomass concentrations, at both batch and continuous operating modes. MFC performance is affected by the operating variables such as initial substrate concentration, external resistor, influent substrate concentration, and dilution rate, and these variables were revealed to have complex interactions by data simulation. The external power generation and energy efficiency were considered as indices for MFC performance. The simulated results explained that an intermediate initial substrate concentration (about 100 mg/L under this reactor configuration) needed to be chosen to achieve maximum overall energy efficiency from substrate in the batch mode. An external resistor with the value about that of the internal resistance boosted the power generation, and a resistor with several times of that of the internal resistance achieved better overall energy efficiency. At continuous mode, dilution rate significantly impacted the steady-state substrate concentration level (thus substrate removal efficiency and rate), and attached biomass could be fully developed when the influent substrate concentration was equal to or higher than 100 mg/L at any dilution rate of the tested range. Overall, this relatively simple model provided a convenient way for evaluating and optimizing the performance of MFC reactors by regulating operating parameters.

scholarly journals Carbon Nanotube/Pt Cathode Nanocomposite Electrode in Microbial Fuel Cells for Wastewater Treatment and Bioenergy Production

2021 ◽  
Vol 13 (14) ◽  
pp. 8057
Author(s):  
Mostafa Ghasemi ◽  
Mehdi Sedighi ◽  
Yie Hua Tan
Keyword(s):  
Electron Microscopy ◽  
Power Generation ◽  
Wastewater Treatment ◽  
Carbon Nanotube ◽  
Microbial Fuel Cells ◽  
Energy Production ◽  
Catalytic Properties ◽  
Internal Resistance ◽  
Cod Removal ◽  
Cathode Catalyst

In this paper, we reported the fabrication, characterization, and application of carbon nanotube (CNT)-platinum nanocomposite as a novel generation of cathode catalyst in microbial fuel cells (MFCs) for sustainable energy production and wastewater treatment. The efficiency of the carbon nanocomposites was compared by platinum (Pt), which is the most effective and common cathode catalyst. This nanocomposite is utilized to benefit from the catalytic properties of CNTs and reduce the amount of required Pt, as it is an expensive catalyst. The CNT/Pt nanocomposites were synthesized via a chemical reduction technique and the electrodes were characterized by field emission scanning electron microscopy, electronic dispersive X-Ray analysis, and transmission electron microscopy. The nanocomposites were applied as cathode catalysts in the MFC to obtain polarization curve and coulombic efficiency (CE) results. The catalytic properties of electrodes were tested by linear sweep voltammetry. The CNT/Pt at the concentration of 0.3 mg/cm2 had the highest performance in terms of CE (47.16%), internal resistance (551 Ω), COD removal (88.9%), and power generation (143 mW/m2). In contrast, for the electrode with 0.5 mg/L of Pt catalyst, CE, internal resistance, COD removal, and power generation were 19%, 810 Ω, 96%, and 84.1 mW/m2, respectively. So, it has been found that carbon nanocomposite cathode electrodes had better performance for sustainable clean energy production and COD removal by MFC.

scholarly journals The effect of systematic error on the accuracy of Michaelis constants and maximum velocities estimated by using the integrated Michaelis–Menten equation (Short Communication)

1974 ◽  
Vol 143 (3) ◽  
pp. 779-781 ◽  
Author(s):  
Peter F. J. Newman ◽  
Gordon L. Atkins ◽  
Ian A. Nimmo
Keyword(s):  
Reaction Time ◽  
Systematic Error ◽  
Substrate Concentration ◽  
Unknown Parameter ◽  
Short Communication ◽  
Systematic Errors ◽  
Product Concentration ◽  
Initial Substrate ◽  
Michaelis Constants ◽  
Initial Substrate Concentration

Systematic errors in initial substrate concentration (s0), product concentration and reaction time give much larger errors in the Michaelis–Menten parameters unless s0 is treated as an unknown parameter. These errors are difficult to detect because the fitted curve deviates little from the data. The effect of non-enzymic reaction is also examined.

scholarly journals Evaluating the Performance of Three Chambers Microbial Salinity Cell (MSC) Subjected to Different Substrate Concentrations to Accomplish Simultaneous Organic and Salt Removal in the Wastewater

2020 ◽  
Vol 11 (1) ◽  
pp. 19-26
Author(s):  
Rustiana Yuliasni ◽  
Nur Zen ◽  
Nanik Indah Setianingsih
Keyword(s):  
Substrate Concentration ◽  
Carbon Cloth ◽  
Anode Chamber ◽  
Initial Substrate ◽  
Conductivity Increase ◽  
Maximum Current ◽  
Maximum Conductivity ◽  
Vulcan Carbon ◽  
Substrate Concentrations ◽  
Initial Substrate Concentration

This study aimed to identify the effect of substrate concentration on the performance of A Three chambers Microbial Salinity Cell (a three chambers MSC). In this study, 3 three chambers MSC was made of plexy glass with total volume of 200 ml.  Alumunium wrapped with with platinum on vulcan carbon cloth were used as electrodes,with each working area 63 cm2. The results showed that a Three chambers Microbial Salinity Cell was able to generate electricity and at the same time removed salinity. The degree of electricity deneration and salinity removal were influenced by initial substrate concentration in the anode chamber. The higher substrate concentration, the better performance of MSC. The best performance of MSC achieved when COD was 2034 mg/L, resulted in maximum  voltage of 0. 44 V, and  maximum current density of 0.29 mA/m2. With % CE was 5.4%. The maximum conductivity increase in salinity chamber was  from 11.2 µS/cm  to 1027 µS/cm (salinity 0.57% ppt).

Influence of So/Xo Ratio on Anaerobic Activity Test

1999 ◽  
Vol 40 (8) ◽  
pp. 9-15 ◽  
Author(s):  
Gloria Moreno ◽  
Arturo Cruz ◽  
Germán Buitrón
Keyword(s):  
Substrate Concentration ◽  
Reaction Rate ◽  
Biomass Concentration ◽  
Sole Source ◽  
Yield Coefficient ◽  
Initial Biomass Concentration ◽  
Activity Test ◽  
Initial Substrate ◽  
Kinetic Coefficients ◽  
Initial Substrate Concentration

The effect of the substrate/microorganism ratio during the development of anaerobic activity test was studied. The experimentation was carried out in serum bottles at 35°C. Two sets of experiments utilizing acetate and an azo dye (blue disperse 79) as the sole source of carbon were studied. It was observed that mixing has an important influence on the results. The initial substrate concentration and the initial biomass concentration had a significant effect on the reaction rate and on the biomass yield coefficient, Yobs. Different kinetic coefficients were found for the case of equal So/Xo ratio, but different initial substrate concentration.

Synthesis of (S)-Tert-Butyl 3-Hydroxybutyrate by Asymmetric Reduction of Tert-Butyl Acetoacetate with Saccharomyces cerevisiae B5

2013 ◽  
Vol 704 ◽  
pp. 12-17
Author(s):  
Zhi Min Ou ◽  
Wen Fei Feng ◽  
Li Xu
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Substrate Concentration ◽  
Asymmetric Reduction ◽  
Optical Purity ◽  
Lower Amount ◽  
High Optical Purity ◽  
Initial Substrate ◽  
Initial Ph ◽  
H 30 ◽  
Initial Substrate Concentration

S)-tert-butyl 3-hydroxybutyrate was synthesized by asymmetric reduction of tert-butyl acetoacetate with Saccharomyces cerevisiae B5 as catalyst. The enantiometric excess of (S)-tert-butyl 3-hydroxybutyrate increased with addition of more amount of substrate. High optical purity of product can be obtained when 6 g/L chloroform was used as inhibitor. The optimum reduction time, temperature, and initial pH of reaction mixture were 60 h, 30 °C, and 6.2. Addition of more biomass and lower amount of substrate helped to get high conversion. Conversion and enantiometric excess of product reached 100% when initial substrate concentration and biomass were 2.0 g/L and 140 g/L with 6 g/L chloroform as inhibitor.

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