Highly selective extraction of uranium by Fe-doped Aurivillius ferroelectrics through piezo-catalysis strategy

The efficient extraction of uranium (U) from aqueous solutions is of great significance for ensuring global energy security and advancing environmental remediation. In this work, a novel Fe 3+ -doped Aurivillius-type ferroelectric material (Fe-BBT-0.15) was developed for enhanced piezo-catalytic U(VI) extraction. The incorporation of Fe 3+ was systematically optimized to improve its intrinsic piezoelectric responsiveness and piezo-catalytic activity. The Fe-BBT-0.15 demonstrated outstanding catalytic performance. Over 85% of 50 mg/L U(VI) was removed after 180 min of the ultrasonication stimulation across a broad pH range of 3.5–8.5. The piezo-catalytic system exhibited strong tolerance to temperature fluctuations, complex background electrolytes, and various competing ions. The reaction pathway was elucidated by integrating the identification of key reactive radicals with in-situ monitoring of H 2 O 2 accumulation. The H 2 O 2 production, co-driven by O 2 reduction and H 2 O oxidation/sonolysis, was attributed to the synergistic interplay of piezoelectric effect and cavitation effect. Combined with the XPS analysis, it was confirmed that the Fe-BBT-0.15 served as a stable “reaction center” and “charge pump”, which were capable of supporting the migration and utilization of charge carriers and reactive free radicals. Furthermore, XRD analysis revealed that U(VI) was immobilized in the form of metastudtite ((UO 2 )O 2 ·2H 2 O), a finding that directly linked the catalytically generated H 2 O 2 to effective uranium solidification. This study provides a high-performance adaptive piezo-catalyst and elucidates the underlying catalytic mechanism, thus, contributing to the advancement of sustainable uranium extraction.