Investigation of Hybrid Microbial Fuel Cells for Enhanced Performance under Solar Irradiation

Abstract

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