LAUSR

The migration and transformation of uranium(U)-bearing pollutants such as 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) with maghemite (γ-Fe2O3) was studied and the interaction mechanism between (γ-Fe2O3 and U (Ⅵ) was explored. Batch experiments confirm that γ-Fe2O3 can effectively remove U (Ⅵ) from an aqueous solution within a short time (R% > 92.01% within 3 min) and has a considerable capacity for U (Ⅵ) uptake (qt: 87.35 mg/g). γ-Fe2O3 has 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 γ-Fe2O3 and U (Ⅵ) under low pH condition. Compared with other radionuclides (e.g., Sr(II) and Cs(I)), U (Ⅵ) was more effectively removed by γ-Fe2O3. The U (Ⅵ) removal by γ-Fe2O3 is primarily electrostatic interactions and precipitation that result in the long-term retardation of uranium in the reactive system. γ-Fe2O3 not only can fast and selectively adsorb U (Ⅵ) but also can be magnetically recycled, demonstrating that γ-Fe2O3 is a cost-effective and promising material for the clean-up of uranyl ions from complex radioactive wastewater.