Synthesis of novel flower-like layered double oxides/carbon dots nanocomposites for U(VI) and 241Am(III) efficient removal: Batch and EXAFS studies
2017; Elsevier BV; Volume: 332; Linguagem: Inglês
10.1016/j.cej.2017.09.011
ISSN1873-3212
AutoresWen Yao, Xiangxue Wang, Liang Yu, Shujun Yu, Pengcheng Gu, Yubing Sun, Chao Xu, Jing Chen, Tasawar Hayat, Ahmed Alsaedi, Xiangke Wang,
Tópico(s)Chemical Synthesis and Characterization
ResumoHerein, a practical and simple calcination method was used to synthesize layered double oxides (denoted as LDO) and layered double oxides/carbon dots nanocomposites (denoted as LDO-C) for U(VI) efficient removal. The U(VI) adsorption on LDO and LDO-C were investigated under various experimental conditions, and the results indicated that U(VI) uptake on LDO and LDO-C were consumingly dependent on pH and ionic strength at pH > 6, and independent of ionic strength at pH < 6. The adsorption processes of U(VI) on LDO and LDO-C were spontaneous and endothermic, and well simulated by pseudo-second-order model. The maximum adsorption capacity of U(VI) on LDO-C was calculated to be 354.2 mg/g at pH = 5.0 and T = 298 K, which was significantly higher than that of U(VI) on LDO (237.6 mg/g). Particularly, BET, F T-IR, XPS and EXAFS analysis suggested that the higher adsorption capacity of LDO-C was mainly attributed to higher specific surface area and more abundant surface oxygen-containing functional groups (e.g. C-OH), and the main interaction mechanisms were surface complexation and electrostatic interactions. In addition, LDO-C also showed higher adsorption capacity of 241Am(III) than LDO. All in all, the efficient removal performance and superior versatility of LDO-C indicated that it could be applied as promising candidate for efficient immobilization of radioactive pollutant in environmental pollution management.
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