Tri-metallic heterojunction MOF-derived light-driven micromotors for dynamic uranium remediation

MOF-derived light-responsive micromotors were constructed from ZIF-8@ZIF-67 precursors. • CdS/ZnCoO heterointerfaces improved photoresponse and interfacial charge transfer. • Active motion enhanced solid–liquid mass transfer for uranium removal. • The optimized micromotor achieved 91.22% U(VI) removal and 361.84 mg g ⁻1 uptake. • Uranium removal involved both surface adsorption and partial reduction to U(IV). Passive diffusion severely limits the mass-transfer efficiency and uranium uptake kinetics of conventional adsorbents for radioactive wastewater treatment. Here, we develop a series of light-responsive MOF-derived micro/nanomotors (MOFtors) to enhance uranium removal through active motion. The MOFtors were derived from ZIF-8@ZIF-67 core–shell precursors and further coupled with CdS to construct Zn/Co/Cd-containing heterostructures. Under UV irradiation (385 nm) and in the presence of H 2 O 2 , the MOFtors exhibited pronounced self-propulsion, which can be ascribed to the synergistic contributions of photothermal effects and photoinduced interfacial electrokinetic processes. Owing to the improved solid–liquid interfacial mass transfer, the optimized MOFtors achieved a U(VI) removal efficiency of 91.22% with an apparent uranium-removal capacity of 361.84 mg g ⁻1 . XPS analysis indicates that uranium removal involves both adsorption and partial reduction from U(VI) to U(IV). The MOFtors also showed good structural stability and retained high removal performance over five cycles. These results highlight the promise of MOF-derived light-responsive micromotors for uranium remediation and offer a feasible route toward dynamic adsorbents for radioactive wastewater treatment. Download: Download high-res image (206KB) Download: Download full-size image