Agric & Bioresources Engineering

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Agric & Bioresources Engineering

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    Electrochemical Characterization of Stainless-Steel Mesh and carbon-felt Electrodes for Enhanced Power Generation in Terrestrial Microbial Fuel Cells.
    (School of Physical Sciences, FUTMINNA, 2024-04-24) Simeon, Meshack Imologie; Alaka, Amarachi C.; Daniela, P.; Olalekan, D. Adeniyi
    Terrestrial Microbial Fuel Cells (MFCs) represent a promising avenue for sustainable energy production, leveraging microbial metabolism to convert organic matter in the soil into electricity. Crucial to MFC performance is selecting electrode materials, which directly interface with electroactive microbes for electron transfer. This study conducts a comparative analysis of surface-modified stainless-steel mesh (SMS) and carbon felt (CF) electrodes in terrestrial MFCs, evaluating their performance metrics and impedance spectroscopy. The SMS electrode, fabricated using the pasting and reinforcement process, demonstrated superior performance with a maximum power of 859 µW compared to the 234 µW power of the commercially available CF electrode. This better performance of the SMS electrode was attributed to its pseudocapacitive behavior, enhancing internal charge storage capacity and overall MFC efficiency. Electrochemical impedance spectroscopy revealed a substantially higher charge transfer resistance (Rct) in the CF electrode, impeding electron transfer processes. Conversely, the SMS electrode exhibited lower Rct and improved diffusion characteristics, facilitating efficient electron transfer and mass transport. Notably, the Rct of the CF electrode was over 40 times higher, while its diffusion coefficient was approximately six times greater compared to the SMS electrode. These findings underscore the significance of tailored electrode materials in optimizing MFC performance and emphasize the utility of impedance spectroscopy in elucidating complex electrochemical processes within MFC systems, thus guiding future advancements in sustainable power production in terrestrial MFCs.
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    The applicability of the Maximum Power-point of Microbial Fuel Cells: Influence of Potential Scan rate and real-time external Load
    (international Society for microbial Electrochemistry amd Technology-ISMET, 2021-09-15) Simeon, Meshack Imologie; Freitag, Ruth
    Performance evaluation of a microbial fuel cell (MFC) is usually done with linear sweep voltammetry (LSV) [1] at a given potential scan rate (PSR) [2]. This evaluation does not often reflect the long-term performance of the MFC under real-time external loads [1]. In this study, the performance of a single-chamber MFC was evaluated with three external loads (1206, 470, and 270 Ohms) calculated from LSV maximum power point (MPP) with three PSRs (0.1, 0.5, and 1 mV/s). The estimated power from the MPP in ascending order of PSR was 61.96, 87.88, and 166.68 mW/m2 at 116.5, 229.6, and 403 mA/m2, respectively. The average power obtained with 1206, 470, and 270 Ohms in the first two hours of operation was 73 + 16.7, 36.3 + 42, and 88.5 + 120.1 mW/m2 at current densities of 124.6 + 14.3, 121.2 + 73.4, and 232.6 + 176.2 mA/m2, respectively. The result showed that overestimation was more pronounced at higher PSRs. Although the MFC was initially underestimated at 0.1 mV/s, this PSR more accurately reflects the true and applicable estimate of the long-term performance of the MF vC. These results are explicitly beneficial for ethe lectrochemical estimation of the actual performance of MFCs under real-time external loads
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    Bio-electrochemical response to selected experimental treatments of a soil-type microbial fuel cell for sustainable bioelectricity generation
    (International conference on sustainable development and technology-Elsevier, 2021-11-02) Simeon, Meshack Imologie; Alfons, R. Weig; Freitag Ruth
    The need to protect the environment has triggered a search for alternative and sustainable energies to replace or drastically reduce the world's dependence on fossil fuels. Bio-electrochemical systems (BES) are among the leading research topics in alternative energy sources due to their multi-functional potential. However, their low energy production rate limits their application in the real world. Therefore, architectural and biological optimization is required to take BES beyond laboratory-scale experiments. In this study, we investigated the interactive influence of electrode materials, electrode spacing, and frequent substrate feeding on microbial community diversity and electrochemical behavior of a soil BES for sustainable power generation. Two electrode materials (carbon felt (CF) and stainless steel/epoxy/carbon black composite (SEC) were tested in a soil microbial fuel cell (S-MFC) under three levels of electrode spacings (2, 5, and 8 cm) and treatment frequencies (4, 6, and 8 days). After 30 days of operation, all MFCs achieved an Open-circuit voltage of 782+12.2 mV regardless of the treatment. However, the maximum power of the CF-MFCs was 12.19 + 1.6 mW/m2 at a current of 15.8 mA/m2, while the SEC-MFCs produced 125.69 + 9.3 mW/m2 at a current of 277.4 + 19.3 mA/m2 under the same experimental conditions. The overall best and sustainable performance (145.3 + 8.03 mW/m2) during the 66-day operating period was obtained with SEC-MFC at 5 cm electrode spacing and treatment frequency of 8 days. 16S rDNA gene amplicon sequencing of DNA samples from the anode, cathode, and point of maximum power (MPP) revealed complex microbial diversity that showed significant compositional changes at the electrodes and MPP. The results showed that too small or too large electrode spacing and frequent substrate loading were not suitable for the MFC configuration in this study, and the electrode material had the greatest impact on S-MFC performance.
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    Experimental Utilization of Urine to Recharge Soil Microbial Fuel Cell for Constant Power Generation
    (2017-02-20) Simeon, Meshack Imologie; Raji O. A
    The simplicity of the soil-based microbial fuel cells (MFCs) makes them very attractive, as perhaps the only natural components they need to run are nutrient-rich soil combined with water to form mud. However, the MFC will cease to produce electricity when the soil runs out of its nutrient-rich characteristics and bacteria. It is against this background that this study was designed to investigate the possible utilization of urine to recharge soil MFCs that have run out of their nutrient-rich characteristics. The mud-watt MFC was utilized for this study. It was run continuously for forty days until the power output was nearly zero. Fresh urine was then introduced into the soil, and the power output was determined. The initial (24 hours after set-up) open circuit voltage (OCV) was 219 mV. A maximum OCV of 731 mV was obtained on day 14 of the study. The OCV of the MFC was 7.31 mV on day 40 before the injection of urine into the soil. Twenty-four hours after the ejection of urine, the OCV was 360 mV and rose to 407 mV forty-eight hours later. The OCV remained constant at this value for fifteen days, after which urine was reinjected. The voltage drop across seven external loads also showed a similar trend. This study has demonstrated that fresh urine can be successfully utilized to recharge a soil-based MFC that has run out of its nutrient-rich characteristics.
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    Extraction and Characterization of Cashew Nut (Anacardium Occidentale) Oil and Cashew Shell Liquid Oil
    (Academic Research International, 2014-05) Idah, P. A.; Simeon, Meshack Imologie; Mohammed M. A.
    This study was carried out to extract oils from cashew shell and its kernel and to characterize the oils, with the view to ascertaining their suitability for consumption and other uses. The Soxhlet apparatus was used for the extraction using hexane as solvent. The physical and chemical properties of the extracted oil were analyzed. The percentage of oil extracted from the shell of the cashew was found to be 25.5%, while that extracted from the kernel was 11.8%. The results of the physical analysis showed that the cashew kernel oil (CKO) is light yellow, while the Cashew Nut Shell Liquid (CNSL) is dark brown. The boiling points for shell and kernel oil were 92 0c and 95 0c, respectively. The cashew kernel oil is non-toxic, and the properties of CNSL conformed, to a greater extent, to those exhibited by linseed oil. This suggests its application in the processing and manufacturing industries. The kernel oil confirmed both in its physical and chemical properties to those of groundnut and melon oil, and thus could be used in the food and pharmaceutical industries.
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    Performance of a Single Chamber Soil Microbial Fuel Cell at Varied External Resistances for Electric Power Generation
    (Journal of Renewable Energy and Environment, 2017-02-14) Simeon, Meshack Imologie; Raji O. A.; Agidi Gbabo; Okoro-Shekwaga
    Soil is beginning to attract research attention as a suitable inoculum for Microbial Fuel Cells (MFCs) designed for remediation and electricity generation, probably due to its high microbial load. However, not much has been done in this aspect beyond laboratory-based experiments. This study was aimed at generating electricity from agricultural soil, utilizing the microorganisms present in the soil, and investigating the performance of the soil MFC across varied external loads. The study used the MudWatt MFC kit inoculated with mud prepared from topsoil collected from a garden. The electrodes, made from carbon felt material with conducting wires made from graphite, were housed in the same chamber and placed 4cm apart. Voltage drops across seven external resistances of 4670, 2190, 1000,n470, 220, 100, and 47 Ω were measured every 24 hours, with a digital multimeter, for 40 days. The maximum open-circuit voltage from this study was 731 mV, whereas the maximum power density was 65.40 m/Wm2 at a current density of 190.1mA/m2. The optimum performance of the MFC was achieved with the 470Ω at an internal resistance of 484.14 Ω. This study revealed that MFCs constructed from agricultural topsoil are capable of producing electrical power continuously, across different external loads, without the addition of any substrate. However, there is a need for further studies to keep the MFC output constant at the maximum achievable power.
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    Polarization and power density trends of a soil-based microbial fuel cell treated with human urine
    (2020-03-14) Simeon, Meshack Imologie; Asoiro FU; Aliyu, M; Raji, OA; Freitag, Ruth
    Microbial fuel cells (MFCs) are bio-electrochemical devices that use microbial metabolic processes to convert organic substances into electricity with high efficiency. In this study, the performance of a soil-based MFC using urine as a substrate was assessed using polarization and power density curves. A single-chamber, membrane-less MFC with a carbon-felt air cathode and a carbon-felt anode fully buried in biologically active soil was constructed to examine the impact of urine treatment on the performance of the MFC. The peak power of the urine-treated MFC was 124.16 mW/m2 and was obtained 24 hours after the first urine addition; a control MFC showed a value of 65.40 mW/m2 in the same period. The treated MFC produced an average power of 70.75 mW/m2 up to 21 days after the initial urine addition; the control MFC gave an average value of 4.508 mW/m2 over the same period. The average internal resistances of the treated MFC and the control MFC obtained after the initial treatment were 269.94 and 1627.89 Ω, respectively. This study demonstrates the potential of human urine to reduce internal losses in soil MFCs and to provide stable power densities across various external resistors. These results are propitious for future advancements in soil MFCs for power generation, utilizing human urine (a readily available source of nutrients) as a substrate.
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    Effects of blending on the phytochemical, functional and proximate properties of Mucuna solannie-based composite flour
    (2022-09-30) Asoiro, Felix; Simeon, Meshack Imologie; Azuka, CE; Orji, Precious Chimaraoge
    Brachystegia eurycoma (BE), Afzelia Africana (AA) and Mucuna solannie (MS) flours were blended (%, w/w) at varying proportions: 50:50, 60:40, 70:30, 80:20 and 100:0, with 100% of flours as the control; then analyzed based on the phyto-chemical, functional and proximate compositions. Tanin, saponin, alkaloid and flavonoid values were 4.19, 1.47, 1.49 and 1.15 mg 100 g-1 dm; 3.44, 0.45, 1.34 and 1.13 mg 100 g-1 dm; and 4.1, 0.61, 1.36 and 1.18 mg 100 g-1 dm in MS, AA and BE flours respectively. Increased AA and BE proportions in MS flour increased the swelling index (1.49% -1.76%) whereas AA and BE inclusions (%) resulted in significant (P≤0.05) increase in the moisture content of the composite flours (8.3% - 14%). Increase in % AA flour inclusion resulted in significant improvement in carbohydrate content while % BE flour inclusion recorded a decrease. As % BE flour inclusion increased from 20% to 40%, % protein content in the blends significantly improved (15.65% - 16.25%) while % AA inclusion, increased protein content by 30%. The study could help to optimize the products made from MS, AA and BE flour blends, in terms of their properties than products made solely from single flour.