Collaborative Research: Understanding the impact of network morphology on ion transport in hydrated polymeric membranes

About This Grant

Critical minerals are essential for products such as electronics, motors, and batteries. The demand for critical minerals could be met in part by recovering them from waste and process streams. However, current recovery processes are expensive, and valuable materials in waste streams often are unrecovered. This project will develop polymeric membranes for use in low-cost filtration-type processes. These membranes will improve the recovery of target ions of critical minerals from aqueous streams. Most polymer membranes are manufactured by methods that result in pores and voids of varying sizes. This project will develop experimental methods to precisely control and measure the sizes of pores and voids in membranes. Using computations and experiments, the research will show that suitable pore sizes can improve recovery of the target ions. This project will improve national security and improve economic competitiveness in critical minerals. Additional benefits include the training and mentoring of teachers and community-college students on modern separation technologies. Polymeric membranes have emerged as versatile, low-cost, and scalable materials systems for a wide variety of gas and liquid separation applications. Such membranes are generally prepared using free radical polymerization, which produce membranes with a heterogeneous pore and network structure. The influence of network heterogeneity on ion transport in hydrated membranes is poorly-understood. This project will pursue a combination of experiments and computer simulations to systematically tune and characterize network heterogeneity in polymer networks and understand its impact on ion transport and separations. Experimental work will implement methods for controlling and quantifying membrane heterogeneity, and measuring the impact of heterogeneity on ion transport and selectivity. Molecular simulations will capture the effects of network heterogeneity and ion-specific interactions. The resulting insights on the role of water-filled voids on ion diffusion and sorption will guide the experimental work. The knowledge generated in this project will immediately impact the field of membrane separations. Unraveling the interplay between membrane heterogeneities and ligand-ion interactions on ion selectivity will impact a variety of contemporary applications of extraction, recycling and reuse of critical minerals. The project includes training of K-12 science teachers on activities relating to membrane separations, development of a hands-on activity to be used in K-12 community outreach events, and training undergraduate researchers from Houston and Austin area community colleges. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.