Development of three-dimensional electrochemical systems for the degradation of persistent contaminants and disinfection

ENG- The objective of this thesis is to assess novel electrochemical techniques for the degradation of persistent organic contaminants and water disinfection, focusing on 3D system methodologies. The initial two chapters of the thesis involved the evaluation of graphite granules and activated carbon granules as particle electrodes, with an additional investigation into the impact of reduced graphene oxide (RGO) coating. Furthermore, the regeneration and reuse of particle electrodes was examined. The incorporation of particle electrodes resulted in improved removal of persistent organic contaminants from water, accompanied by a reduction in energy consumption within the system. Additionally, the inclusion of particle electrodes helped to mitigate the formation of toxic by-products typically generated in electrochemical processes involving the presence of chloride. The application of RGO coating also yielded positive outcomes, and partial regeneration of the granules was successfully achieved, enabling their reuse across multiple cycles, even in real wastewater matrices. In the final section of the thesis, graphene sponge electrodes were fabricated using a cost-effective bottom-up synthesis approach, incorporating RGO coating. These electrodes were employed as both anodes and cathodes for electrochemical disinfection, successfully eliminating E. coli without the contribution of chlorine species. Near-total eradication of E. coli was observed in both phosphate buffer and actual tap water. Additionally, the system's energy consumption was reduced through the application of intermittent current. Overall, the thesis proves the great potential of 3D electrochemical methods for the treatment of both persistent contaminants and disinfection and addresses some of the main limitations of the electrochemical methods, such as the high energy consumption, high cost of electrodes and formation of toxic by-products