Date of Award

2020

Degree Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Chemistry

Abstract

Various strategies have been established to enhance the extracellular electron transfer and energy output capability of microbial fuel cells, with the majority being aimed at anode modification. The anode has a significant impact on the electricity generation performance of MFCs because it is in direct contact with the microorganisms. The materials of the anode should be favorable for the bacterial cell and capable to facilitate the electron transfer. Developing of an electrode using low-cost and effective materials assists to enhance the bacterial cell attachment and extracellular electron transfer. This provides a significant improvement in MFC performance. In this study, clay used as a new material to modify the ITO (indium tin oxide) electrode in order to enhance the attachment and the current production of Shewanella oneidensis MR-1. Two types of clay containing different amounts of iron situated in the octahedral sites were used to modify ITO electrodes, namely nontronite NAu-1, and montmorillonite (Wyoming) SWy-1. Synthetic montmorillonite SYn-1 which is iron-free clay was used for comparison. The interaction between the bacterial cells and the clays studied by potential-step chronoamperometry, cyclic voltammetry, confocal microscopy, and scanning electron microscopy (SEM). The obtained results showed that the current densities generated upon ITO electrode modification using the NAu-1 and SWy-1 iron-containing clays were 19 and 3 times higher than that produced using the bare ITO electrode. No current density was obtained when utilizing the synthetic montmorillonite SYn-1 clay. SEM and confocal microscopy observations confirmed the increased coverage per-centage of the bacterial cells attached to NAu-1/ITO and SWy-1/ITO electrodes compared to the bare ITO. Clay film porosity, particle size, film thicknesses, and surface hydrophilicity of the clay-modified electrode were examined. The results indicated that iron the clay worked as a mediator in the clay film transferring the electrons and attracted bacterial cells to attached to the CMEs.

Creative Commons License

Creative Commons License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 License.

Available for download on Saturday, October 08, 2022

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