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

• DOI: 10.1016/j.envres.2022.112917
• Publication Date: 2022-02-11T01:12:02Z
• Authors: Minhua Su; Hong Li; Zequan Liu; Hairong Peng; Shuai Huang; Ying Zhou; Changzhong Liao; Gang Song; Diyun Chen
• Keywords: Uranium; Adsorption; Wastewater; 01 natural sciences; Humic Substances; Water Pollutants, Chemical; 0104 chemical sciences; 0105 earth and related environmental sciences

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 (γ-Fe2O3) particles was studied and the interaction mechanism was explored as well. Batch experiments confirm that γ-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). γ-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 γ-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 γ-Fe2O3. The U (Ⅵ) removal by γ-Fe2O3 is primarily due to electrostatic interactions and precipitation that result in the long-term retardation of uranium. 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 radioactive wastewater.