Biomimetic phosphatization of nano zero-valent iron for thorium removal and waste remediation from rare earth leachates

The selective removal of thorium (Th) from rare earth element (REE)-associated mineral leachates is essential for improving REE utilization and mitigating radioactive hazards. However, high concentrations of competing metal ions and the lack of environmentally friendly separation strategies make Th(IV) recovery challenging. Here, we report a biomimetic phosphatization approach using nano zero-valent iron (ZVI bm ) and phosphoric acid to construct phosphate-coordinated surfaces for selective Th immobilization. Density functional theory (DFT) calculations reveal that H 3 PO 4 -induced surface reconstruction strengthens Th(IV) adsorption by 82.7 % (energy change from −8.004 to −14.617 eV). Batch experiments using acidic leachates containing 48.8 mg/L Th(IV) demonstrate over 98.8 % recovery efficiency at a low dosage of 0.3 g/L, reaching 99.7 % within 3.0 h. This study provides a green and effective strategy for actinide separation via surface coordination and mineralization chemistry, offering promise for radioactive waste remediation and resource recovery.