A promising electrochemical approach involves the use of redox-copolymers, which facilitate the reversible capture and release of REEs through controlled electrochemical processes. These copolymers combine ion-exchange groups, such as carboxylic acids, which adsorb REEs, with redox-active groups like ferrocene moieties, which can be electrochemically regulated to enable efficient regeneration and desorption. This redox-switchable copolymer system allows for highly efficient, reversible REE recovery. In our study, we demonstrated an yttrium (Y) adsorption capacity of 69.4 mg/g polymer, with electrochemical regeneration yielding near 100% efficiency. Additionally, other REEs, such as cerium (Ce), neodymium (Nd), europium (Eu), gadolinium (Gd), and dysprosium (Dy), were similarly recovered, highlighting the effectiveness and sustainability of electrochemically regenerable ion-exchange copolymers for REE recovery. This technique not only reduces reliance on chemical reagents but also offers significant scalability and modularity, making it an ideal candidate for sustainable REE extraction.
Electrochemical separation can also be enhanced through electro-precipitation, particularly when using both direct current (DC) and alternating current (AC) modes. By leveraging the redox properties of cerium (Ce) and exploiting the distinct solubility behaviors of Ce and lanthanum (La) hydroxides in acidic conditions, we achieved over 90% Ce recovery while minimizing the co-precipitation of La. This method was further confirmed through its successful application to iron slag leachate, where nearly 90% Ce recovery was achieved after optimizing the pH conditions. This selective process significantly improved Ce purity and minimized waste, further underscoring the potential of electrochemical methods for high-purity REE extraction.