Highly-efficient and easy separation of γ-Fe2O3 selectively adsorbs U(VI) in waters

The migration and transformation of uranyl [U (VI)] ions in the environment are quite dependent on the geological condition in particular with the site enriched in Fe. In this study, the interfacial interaction of U (VI) ions with maghemite (gamma-Fe2O3) particles was studied and the interaction mechanism was explored as well. Batch experiments confirm that gamma-Fe2O3 can effectively remove U (VI) from an aqueous solution within a relatively short reaction time (R% > 92.01% within 3 min) and has a considerable capacity for U (VI) uptake (qt: 87.35 mg/ g). gamma-Fe2O3 displays an excellent selectivity for U (VI) elimination. Results on the effects of natural organic matter such as humic acid (HA) indicated that HA could promote the interfacial interaction between gamma-Fe2O3 and U (VI) under acidic conditions. Compared with other radionuclides (e.g., Sr(II) and Cs(I)), U (VI) was more effectively removed by gamma-Fe2O3. The U (VI) removal by gamma-Fe2O3 is primarily due to electrostatic interactions and precipitation that result in the long-term retardation of uranium. gamma-Fe2O3 not only can fast and selectively adsorb U (VI) but also can be magnetically recycled, demonstrating that gamma-Fe2O3 is a cost-effective and promising material for the clean-up of uranyl ions from radioactive wastewater.

Automated summary

This study investigated the interaction between U (VI) ions and maghemite particles, and found that maghemite showed excellent selectivity for U (VI) removal, with organic matter promoting the interfacial interaction under acidic conditions.