Development of ion exchange membranes for resource recovery and impurity removal in electrodialysis

Abstract

In metal production and processing, large amounts of aqueous streams containing both metallic and non-metallic species are generated when extracting the desired bulk metals. While some of the remaining diluted compounds, such as rare earth and noble metals, can be of great value, their concentration in the solution is often too low for cost-effective recovery through established methods. Additionally, a significant challenge in hydrometallurgy lies in the unwanted impurities present in the raw materials, leading to increased energy consumption and potential harm. This Ph.D. project aims to strategically manipulate ion exchange membrane (IEM) design, through microstructural or surface modifications, to achieve two crucial objectives: the removal of impurities and/or the recovery of precious metals from hydrometallurgical process streams to support the collaborative industrial partners in their transition toward a circular economy. The developed IEMs have demonstrated remarkably enhanced separation and recovery capabilities through the electrodialysis process. This doctoral study marks a significant milestone in the development of IEMs, ranging from the meticulous fine-tuning of membrane materials in the laboratory to rigorous testing and, ultimately, the validation of their effectiveness with real industrial solutions. Consequently, membrane technology within the realm of hydrometallurgy presents a promising solution to address the challenges associated with resource scarcity and the growing demand in numerous industries.