Chemical and Electrochemical Processes at Solid/Liquid Interfaces in Materials for Sanitation and Neural Stimulation

Abstract

Chemical and electrochemical processes at solid/liquid interfaces are key to diverse and wide range of applications. Hence, the investigation of these reactions is crucial to develop, advance, and improve technologies across numerous fields. The applications chosen as the focus of this dissertation are sanitation and neural stimulation. Sanitation challenges are an urgent global issue for which solutions are being actively developed and improved. This work aims to provide options to overcome some of the limitations found in current technologies in three areas. First, to address user adoption of sanitation facilities, electrochemical modulation of p-cresol was, for the first time, evaluated as an option for malodor nuisance control. It was demonstrated that the electrochemical oxidation of p-cresol can generate 4-hydroxybenzaldehyde following the introduction of chloride ions into the supporting electrolyte. Second, to address nutrient pollution caused by effluents with high levels of ammonium and phosphate from non-sewered sanitation systems and on-site wastewater treatment systems, silicate-based minerals (i.e., clinoptilolite and Polonite) were explored as scalable, affordable, and non-biological options to remove and recover nutrients from these effluents. Clinoptilolite and Polonite were installed and evaluated in our on-site wastewater treatment system, resulting in an increased removal performance of total N and total P from 47.5% to 84.1% and 32.3% to 78.9% respectively. Lastly, to improve the performance of neural stimulation devices, graphenated carbon nanotubes were investigated, for the first time, as an alternative material for neural electrodes. It was demonstrated that graphenated carbon nanotubes can be decorated with platinum nanoparticles to create platinum 3D structures with high cathodal charge storage capacitance and low impedance.