The growth of global population has been increased continuously. Because of this phenomena, the energy demand has been also increased sharply. So, the conventional fossil fuels are running out. To full fill the energy demands, humans are burning larger quantity of fossil fuels which results in the higher carbon dioxide concentration in atmosphere. Therefore, it is essential improving renewable, sustainable energy generating technology. Nowadays, microbial fuel cell (MFC) technology become the main solution for this situation to solve energy and environmental related problems. Because microbial fuel cell (MFC) technology can generate electricity from wastewater. However, there are some limitations such as low efficiency and high cost materials. Thus, this research is conducted to improve low efficiency of microbial fuel cell (MFC) technology by application of solar fuel. First, hybrid-MFC System is invented by application of suitable photoactive material. In this research, TiO2 nanotube arrays (TNT) are used as photoanode to use solar energy. TiO2 nanotube arrays (TNT) have high photostability, high electron transfers ability and broad absorption range. Additional electrons are generated from photoanode under irradiation and they can be involved in MFC system. By this effect, the power density of hybrid-MFC is increased 46.8 % compared to power density of normal MFC. Second, investigation of methylene blue (MB) degradation in hybrid-MFC is conducted. Methylene blue (MB) is used for various purposes. Especially, it is mainly used as a dye. The release of those chemicals in the ecosystem can be a critical source of non-aesthetic pollution, eutrophication and perturbations in the aquatic ecosystem. To create new approach for this problem, Methylene blue (MB) is degraded by TiO2 nanotube arrays (TNT) photoanode and bio-anode in hybrid-MFC system. Third, enhanced power generation in microbial fuel cells (MFCs) with modification of carbon fiber brush anode is investigated. Carbon fiber brush electrodes have been used to provide high surface areas for growth of microorganism and enhanced performance in microbial fuel cells (MFCs). Several modifications for anode in microbial fuel cells (MFCs) have been a successful way for increasing efficiency of MFC such as high-temperature ammonia gas treatment. But these methods are complicated and costly. Therefore, in this research simple and less expensive modification at carbon fiber brush anode with heat and acid treatment is conducted. ⓒ 2017 DGIST
Table Of Contents
I. Introduction 1-- 1.1 Research Background 1-- 1.2 References 4-- II. Equipment 7-- 2.1 Field Emission Scanning Electron Microscope (FE-SEM) 7-- 2.2 Potentiostat 8-- 2.3 X-ray Photoelectron Spectrometer (XPS) 9-- 2.4 X-ray Diffractometer (XRD) 11-- 2.5 Gas Chromatography (GC) 12-- 2.6 Ultraviolet–Visible spectroscopy (UV-Vis) 14-- 2.7 References 16-- III. Photo- coupled Bio-Anode: A New Approach for Improved Microbial Fuel Cell Performance 18-- 3.1 Introduction 18-- 3.2 Experimental Section 20 -- 3.2.1 Chemicals and materials 20-- 3.2.2 Preparation of SEM samples 23-- 3.2.3 Microbial Fuel Cell (MFC) assembly and operation 23-- 3.2.4 Microbial Fuel Cell (MFC) medium 24-- 3.2.5 Synthesis of TiO2 nanotube arrays (TNT) photoanode 24-- 3.2.6 Characterization of TiO2 nanotutbe arrays (TNT) photoanode 25-- 3.2.7 Evaluation photocurrent of TiO2 nanotutbe arrays (TNT) photoanode 25-- 3.2.8 Microbial Fuel Cell (MFC) characterization 25-- 3.3 Results and Discussion 26-- 3.3.1 FE-SEM Analysis of photoanode and microorganism on the anode surface 27-- 3.3.2 XRD patterns of TiO2 nanotube arrays (TNT) photoanode 28-- 3.3.3 XPS analysis of TiO2 nanotube arrays (TNT) photoanode 28-- 3.3.4 Photocurrent measurement of TiO2 nanotube arrays (TNT) photoanode 30-- 3.3.5 Performance evaluation of hybrid-MFC 31-- 3.3.6 Electrochemical characterization of hybrid-MFC 33-- 3.3.7 CO2 photoreduction test TiO2 nanotube arrays (TNT) photoanode 34-- 3.4 Conclusions 37-- 3.5 References 38-- IV. Electrochemical Degradation of Methylene Blue (MB) Powered by Photo- coupled Bio-Electricity in Hybrid-Microbial Fuel Cell 43-- 4.1 Introduction 43-- 4.2 Experimental section 44-- 4.2.1 Chemicals and materials 44-- 4.2.2 Reactor construction and operation 45-- 4.2.3 Evaluation of methylene blue (MB) decomposition in hybrid-MFC 47-- 4.2.4 Evaluation of power outputs of the hybrid-MFC 47-- 4.3 Results and discussion 48-- 4.3.1 Evaluation of power generation of hybrid-MFC 48-- 4.3.2 Degradation performance of hybrid-MFC 49-- 4.4 Conclusions 54-- 4.5 References 55-- V. Investigation of Air-cathode Single Chamber MFC Performance with Modified Carbon Fiber Brush Anode 57-- 5.1 Introduction 57 -- 5.2 Experimental section 58 -- 5.2.1 Chemicals and materials 58-- 5.2.2 Microbial fuel cell (MFC) configuration and anode pretreatments 58 -- 5.2.3 Microbial Fuel Cell (MFC) inoculum, substrate and medium 59-- 5.2.4 Analysis method 59 -- 5.3 Results and discussion 60-- 5.3.1 Power generation using different pretreatment anodes 60 -- 5.3.2 Surface characteristics of carbon fibers with different treatments 62-- 5.4 Conclusions 65-- 5.5 References 66 -- VI. Conclusions 68
