Interactions between Th(IV) and graphene oxide: experimental and density functional theoretical investigations
Interactions between Th(IV) and graphene oxide: experimental and density functional theoretical investigations
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Th(IV) 和氧化石墨烯之间的相互作用：实验和密度泛函理论研究
DOI：
10.1039/c3ra45938a
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发表时间：
2014-01-01
期刊：
影响因子：
3.9
通讯作者：
Shi, Wei-Qun
中科院分区：
文献类型：
--
作者：
Bai, Zhi-Qiang;Li, Zi-Jie;Shi, Wei-Qun
氧化石墨烯（GO）因其在各个科学领域的广泛应用，近年来受到越来越多的研究。在这项工作中，Th（IV）到氧化石墨烯（GO）的吸附进行了研究，在环境条件下使用一个批处理方法。吸附动力学被认为是快速的，拟合伪二级模型非常好，与平衡时间约为10分钟。吸附强烈依赖于溶液的pH值，但独立的离子强度的解决方案。在pH值为2.60 ± 0.05时，Th（IV）的最大吸附容量可达214.6 mg g−1，且Th（IV）可通过1.0 M HNO 3从GO中轻松解吸。热力学研究表明，Th（IV）在GO上的吸附是一个吸热的自发过程。扫描电子显微镜（SEM）的结果表明，明显的表面形貌的变化诱导的Th（IV）吸附的GO。此外，通过红外光谱（IR）和扩展X射线吸收精细结构（EXAFS）光谱结合密度泛函理论（DFT）计算研究了Th（IV）与GO的相互作用机理. EXAFS结果表明，Th（IV）与第一配位壳层中的~（18）或~（19）个氧原子成键，Th-O键的平均键长为~ 2.45A。DFT计算进一步证实了实验和EXAFS结果的合理性。这项工作证明了GO在预浓缩和去除钍和其他四价锕系元素以恢复和修复环境方面提供的巨大潜在机会。
Graphene oxide (GO) has been receiving increasing research efforts in recent years because of its wide applications in various scientific fields. In this work the sorption of Th(IV) onto graphene oxide (GO) was studied using a batch method under ambient conditions. The sorption kinetics were found to be fast and fitted the pseudo-second-order model very well, with an equilibrium time of about 10 min. The sorption is strongly dependent on the solution pH but independent of the ionic strength of the solution. The maximum sorption capacity of as high as 214.6 mg g−1 can be achieved at pH 2.60 ± 0.05, and Th(IV) can be desorbed readily from the GO with 1.0 M HNO3. The thermodynamic investigations revealed that the sorption of Th(IV) on the GO was an endothermic and spontaneous process. The Scanning Electron Microscopy (SEM) results indicated obvious surface morphology changes of the GO induced by Th(IV) sorption. Furthermore, the interaction mechanism of Th(IV) and the GO was investigated by infrared (IR) spectroscopy and extended X-ray absorption fine structure (EXAFS) spectroscopy combined with density functional theory (DFT) calculations. The results of EXAFS indicated that Th(IV) was bonded to ∼8 or 9 oxygen atoms and the average bond length of Th–O was estimated to be ∼2.45 A in the first coordination shell. The DFT calculations further confirm the rationality of experimental and the EXAFS results. This work demonstrates the tremendous potential opportunities offered by GO in pre-concentration and removal of thorium and other tetravalent actinides for the recovery and remediation of the environment.