Collaborative Innovation Center for Advanced Nuclear Energy Technology, INET, Tsinghua University, Beijing, 100084, People's Republic of China.
Beijing Municipal Research Institute of Environmental Protection, Beijing, 100084, People's Republic of China.
Environ Sci Pollut Res Int. 2019 Oct;26(29):29669-29678. doi: 10.1007/s11356-019-06149-z. Epub 2019 Aug 11.
Graphene oxide (GO) was prepared, characterized, and applied for adsorption of Sr(II) in aqueous solution. The adsorption capacity was calculated to be 137.80 mg/g according to the Langmuir model. The observation by scanning electron microscope with energy dispersive X-ray detector (SEM-EDX), high-resolution transmission electron microscope (HRTEM), and X-ray diffraction (XRD) revealed the crystal structure of Sr compound on the surface of graphene sheets. The analyses by the Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) indicated the involvement of O-C=O, C-O, and C-O-C groups during the adsorption. The X-ray absorption fine structure (XAFS) analysis provided the detail information of GO-Sr composites, and the fitting results were given by Sr(HCOO) and SrCO model, and the coordination numbers (CN) and interatomic distances (R) of Sr-O shell and Sr-C shell were calculated. The adsorption mechanism of Sr(II) was attributed to complexation between Sr and the acidic oxygen-containing groups, which lead to the agglomeration of graphene oxide. Two types of crystals were proposed. Type 1 was formed by coordination between Sr(II) and O-C=O groups, and type 2 was formed by coordination between Sr(II) and C-O/C-O-C groups.
氧化石墨烯（GO）被制备、表征，并应用于水溶液中 Sr(II) 的吸附。根据 Langmuir 模型，计算出吸附容量为 137.80mg/g。通过扫描电子显微镜结合能谱仪（SEM-EDX）、高分辨率透射电子显微镜（HRTEM）和 X 射线衍射（XRD）观察到 Sr 化合物在石墨烯片表面的晶体结构。傅里叶变换红外光谱（FTIR）和 X 射线光电子能谱（XPS）分析表明，在吸附过程中涉及 O-C=O、C-O 和 C-O-C 基团。X 射线吸收精细结构（XAFS）分析提供了 GO-Sr 复合材料的详细信息，拟合结果由 Sr(HCOO) 和 SrCO 模型给出，计算了 Sr-O 壳和 Sr-C 壳的配位数（CN）和原子间距离（R）。Sr(II) 的吸附机制归因于 Sr 与酸性含氧基团之间的络合，这导致了氧化石墨烯的聚集。提出了两种类型的晶体。类型 1 是由 Sr(II) 和 O-C=O 基团之间的配位形成的，类型 2 是由 Sr(II) 和 C-O/C-O-C 基团之间的配位形成的。
