M. Wang, J. Park, S. Tay, R. Kingsbury
Princeton Univeristy,
United States
Keywords: industrial wastewater, critical minerals, resource recovery
Summary:
As the world is transitioning to sustainable energy systems, non-fuel minerals such as cobalt and copper are in increasing demand due to their critical role in renewable energy technologies. Recovering critical minerals from waste is gaining increasing attention as a strategy to stabilize and diversify their supply chains. Industrial activities, including power generation and mineral and fuel refining, often discharge wastewater rich in dissolved critical minerals. This has motivated numerous research initiatives to develop membrane materials and systems for enhanced mineral separation and recovery. However, the characteristics of industrial wastewater are highly diverse, and complete water quality information (including dissolved mineral concentrations) is often unavailable. As a result, researchers frequently rely on synthetic wastewater compositions that may differ significantly from real conditions. Since water quality has a substantial impact on separation performance, this discrepancy slows the progress of technology development and hinders its translation to real-world applications. Here, we present a comprehensive review of the composition and critical mineral content of major industrial wastewaters. Our goal is to provide the necessary information to assess the potential for recovering critical minerals, and to establish realistic conditions for membrane research studies. Our review discusses 1) the quantity of wastewater from industrial activities in the U.S., 2) the expected water chemistry (e.g., pH and concentrations of background ions such as sodium and sulfate), 3) the expected concentrations of critical minerals, and 4) an assessment of the variability across and within industries. We will close by highlighting key takeaways for the membrane research and manufacturing community, such as how to establish representative wastewater compositions for testing new materials, as well as the opportunities and challenges for membrane-based resource recovery.