Enabling Metal Sustainability with Polymer Inclusion Membranes: A Critical Review
Adroit T. N. Fajar, Masahiro Goto
Abstract
Polymer inclusion membranes (PIMs) have shown excellent performance in separating metal ions—a critical step in metal recycling processes. However, progress in PIM research has been limited to empirical approaches that typically require redundant membrane fabrication optimizations. Recent reports may provide essential insight into basic knowledge on the nature of the membrane and what challenges and disputes need to be addressed. In this review, we first introduce a basic understanding of how a PIM works in metal separation and the brief history behind its invention. Fundamental principles of the membrane design are established based on consistent data trends in the literature. We then highlight recent findings that have implications for both practical applications and theoretical consequences. In addition, challenges to understanding plausible mechanisms and transport models across PIMs are identified systematically. Finally, we include some perspective on each finding and an outlook regarding the future direction of PIM research, focusing on the application as a metal recovery technology.