Electrochemical Treatment of Mining and Oilfield Wastewater Using Recycled Titanium Alloy Electrodes

This thesis explores the integration of circular economy principles into wastewater treatment through the innovative use of recycled Ti-6Al-4V titanium alloy electrodes. By repurposing titanium alloys from metal additive manufacturing (AM) waste, the research aims to address the treatment of acidic and oil-contaminated industrial wastewater in a sustainable manner. The recycled electrodes demonstrate notable stability and fouling resistance in challenging acidic conditions, attributed to their unique surface porosity and conductive properties. Electrochemical processes, including hydrogen evolution at the cathode, facilitate metal ion precipitation and destabilize surfactant-stabilized oil droplets. Cyclic voltammetry and long-term stability tests highlight the electrodes’ resilience, providing an effective alternative to conventional materials. A key discovery is the role of the electric double layer (EDL) surrounding hydrogen bubbles in neutralizing charged contaminants. Sodium ions within the EDL enhance charge screening, enabling efficient aggregation and removal of contaminants. Additionally, the effect of varying electrolyte compositions on EDL stability was investigated to optimize treatment conditions. These findings support the potential for recycled titanium electrodes to serve as cost-effective and scalable alternatives to conventional materials in industrial water remediation. By bridging waste generation in the metal AM industry with the needs of wastewater treatment, this work underscores the transformative potential of cross-sector synergy within a circular economy. Future research will focus on molecular modeling of the EDL to deepen understanding of ion interactions and further refine the electrochemical processes. Advisor: Li Tan