A critical review of electrochemical strategies for selective uranyl recovery from radioactive wastewater and seawater

The rapid advancement of nuclear energy and extensive uranium resource exploitation have led to the environmental release of toxic and radioactive uranium, posing serious threats to ecosystems and human health. Thus, efficient and selective extraction of uranyl (U(VI)) from wastewater and seawater is critical for resource sustainability, pollution mitigation, and safe nuclear development. Electrochemical techniques, including electro-adsorption, electrocatalysis, and photo-electrocatalysis, have emerged as promising approaches for uranyl recovery. This review systematically summarizes advances in electrode materials, encompassing powder-based and self-supporting architectures, with an emphasis on preparation, performance, and limitations. Mechanistic insights into electrochemical uranyl extraction are presented, focusing on the principles of electro-adsorption, electrocatalysis, and photo-electrocatalysis, as well as the impact of electrode properties on uranyl extraction efficiency. Key challenges in treating fluoride-rich wastewater, uranium mining wastewater, and seawater are addressed, demonstrating the tailored application of electrochemical strategies in complex environments. Critical characterization techniques for identifying and quantifying extracted uranium products are also reviewed, underscoring the potential of electrochemical approaches for sustainable uranium recovery.