Document Details
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Document Type |
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Thesis |
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Document Title |
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Using of microbial biotechnology for renewable electrical energy production in a microbial fuel cell reactor استخدام التقنية الحيوية الميكروبية لإنتاج الطاقة الكهربائية المتجددة في مفاعل خلية الوقود الميكروبي |
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Subject |
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biological sciences department |
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Document Language |
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Arabic |
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Abstract |
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Microbial fuel cell (MFC) is considered to be a recent and promising technology, which presents potential solutions for the global energy crisis, climate change problems and environmental pollution, via utilizing of some bacteria to breakdown the organic pollutants in the wastewater and releasing energy, which will be converted to electricity in the MFC reactor. This study aimed to construct costless MFC reactor with high efficiency. It consists of two compartments connected to each other through electrical circuit via variable external resistance, as well as they connected to each other by salt bridge. An experiment for electrical power production was carried out, where maximum voltage yield at the external resistance 30Ω was 401mV, power density 409.16mW/m2 (2680.01mW/m3), and the coulombic efficiency of 16.17%. Three mediators for electron shuttling were evaluated (methylene blue, neutral red and potassium ferricyanide). Methylene blue gave the maximum voltage yield of 684mV, power density 1190.47mW/m2 (7797.60mW/m3). This improved the rate of voltage yield by 70.57% from the basal experiment. On the other hand, neutral red voltage recorded 482mV, power density 591.15mW/m2 (3872.06mW/m3), Whereas, potassium ferricyanide recorded maximum voltage of 523.6mV, power density of 697.60mW/m2 (4569.28mW/m3). The coulombic efficiency for previous experiments was 19.74, 18.72 and 13.64%, respectively. From these results it was clear that the methylene blue is the best tested mediator to apply in the next experiments. A three – phases of statistical optimization for multi – factors experiments were applied, for optimizing both, medium's constitutes and the reactor operational conditions. In the first phase Plackett – Burman design was applied for the evaluation of medium's components significantly, and to evaluate the effect of each component on the voltage generation. It has been obvious that glucose, KCl and NaHCO3 were the most major significant factors, with main effect: 84, 51 and – 44%, respectively. When the optimized new formula of medium obtained from Plackett – Burman design, was applied in the confirmatory experiment, it has been revealed the increasing voltage yield by 5.30% compared to the basal medium. In the second phase, the three significant factors obtained from the previous design, was further optimized by Box – Behnken design, where new formula [g/l (glucose 8.5, NaHCO3 0.2 and KCl 0.8)] was operated in a confirmatory experiment. It achieved 8.0% increase in yield after optimization compared to basal medium. The third approach was to optimize MFC reactor's operation conditions, including: temperature, initial anodic compartmental pH and salt bridge's components concentrations (Agar and KCl). Application of central composite design, which achieved 25.91% optimization in voltage yield comparing to the basal conditions at the basal medium, and it was performed when the temperature shifted to 32oC, pH maintained at 7.0 and the salt bridge concentration of components was modified to Agar 8.0g/100ml and KCl 2.9g/100ml. The recorded voltage at the external resistance of 30Ω was 861.27mV. MFC technology was used in this work to remediate the organic pollutants in sewage wastewater and electricity production simultaneously. Three experiments have been conducted, in the first MFC reactor was used directly, the results showed reducing in chemical oxygen demand (COD) from 4731mg/l to 2885.91mg/l, by the removal average of 39%, and voltage yield was 218.39mV. In the second experiment, when methylene blue was used as a mediator, as well as the whole previous experimental conditions, removal of COD was 57% with voltage yield 335.20mV. In the final experiment the whole statistically optimized results obtained from the previous experiments were all applied here and the results indicated removal of COD was 61% with voltage yield 578.63mV. |
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Supervisor |
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Prof. Khaled M. Ghanem |
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Thesis Type |
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Doctorate Thesis |
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Publishing Year |
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1433 AH
2012 AD |
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Co-Supervisor |
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Prof. Saleh M. Al-Garni |
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Added Date |
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Monday, April 30, 2012 |
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Researchers
| عبد الله ناصر الشهري | Al-Shehri, Abdullah Nasser | Researcher | Doctorate | |
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