Details

Autor(en) / Beteiligte

• Li, Zi-Jie
• Wang, Lin
• Yuan, Li-Yong
• Xiao, Cheng-Liang
• Mei, Lei
• Zheng, Li-Rong
• Zhang, Jing
• Yang, Ju-Hua
• Zhao, Yu-Liang
• Zhu, Zhen-Tai
• Chai, Zhi-Fang
• Shi, Wei-Qun

Titel

Efficient removal of uranium from aqueous solution by zero-valent iron nanoparticle and its graphene composite

Ist Teil von

• Journal of hazardous materials, 2015-06, Vol.290, p.26-33

Ort / Verlag

Netherlands: Elsevier B.V

Erscheinungsjahr

2015

Link zum Volltext

Quelle

MEDLINE

Beschreibungen/Notizen

• •Uranium removal by ZVI-nps: independent of pH, the presence of CO32−, humic acid, or mimic groundwater constituents.•Rapid removal kinetics and sorption capacity of ZVI-nps is 8173mgU/g.•Two reaction mechanisms: sufficient Fe0→reductive precipitation as U3O7; insufficient Fe0→hydrolysis precipitation of U(VI).•Fe/graphene composites: improved kinetics and higher U(VI) reduction ratio. [Display omitted] Zero-valent iron nanoparticle (ZVI-np) and its graphene composites were prepared and applied in the removal of uranium under anoxic conditions. It was found that solutions containing 24ppm U(VI) could be completely cleaned up by ZVI-nps, regardless of the presence of NaHCO3, humic acid, mimic groundwater constituents or the change of solution pH from 5 to 9, manifesting the promising potential of this reactive material in permeable reactive barrier (PRB) to remediate uranium-contaminated groundwater. In the measurement of maximum sorption capacity, removal efficiency of uranium kept at 100% until C0(U)=643ppm, and the saturation sorption of 8173mgU/g ZVI-nps was achieved at C0(U)=714ppm. In addition, reaction mechanisms were clarified based on the results of SEM, XRD, XANES, and chemical leaching in (NH4)2CO3 solution. Partially reductive precipitation of U(VI) as U3O7 was prevalent when sufficient iron was available; nevertheless, hydrolysis precipitation of U(VI) on surface would be predominant as iron got insufficient, characterized by releases of Fe2+ ions. The dissolution of Fe0 cores was assigned to be the driving force of continuous formation of U(VI) (hydr)oxide. The incorporation of graphene supporting matrix was found to facilitate faster removal rate and higher U(VI) reduction ratio, thus benefitting the long-term immobilization of uranium in geochemical environment.