Interaction mechanism of uranium(VI) with three-dimensional graphene oxide-chitosan composite: Insights from batch experiments, IR, XPS, and EXAFS spectroscopy
Interaction mechanism of uranium(VI) with three-dimensional graphene oxide-chitosan composite: Insights from batch experiments, IR, XPS, and EXAFS spectroscopy
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铀（VI）与三维氧化石墨烯-壳聚糖复合材料的相互作用机制：来自批量实验、红外、XPS 和 EXAFS 光谱的见解
DOI：
10.1016/j.cej.2017.07.067
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发表时间：
2017-11-15
影响因子：
15.1
通讯作者：
Shi, Weiqun
中科院分区：
文献类型：
--
作者：
Huang, Zhiwei;Li, Zijie;Shi, Weiqun
为了高效、便捷地处理放射性废水，制备了氧化石墨烯-壳聚糖气凝胶（GO-CS），并将其用于铀（VI）的去除。气凝胶对铀（VI）的吸附与接触时间、溶液pH、离子强度、初始铀浓度和竞争金属离子有关。在较宽的pH范围内，例如，在pH为3.5、5.0和8.3时，铀的吸附量分别为200、319.9和384.6 mg/g。采用傅里叶变换红外（FT-IR）、x射线光电子能谱（XPS）和扩展x射线吸收精细结构能谱（EXAFS）等方法系统阐明了U（VI）与GO-CS的相互作用机理。研究发现，铀（VI）的吸附主要是由于GO-CS上锚定的-COO、-OH和-NH2基团在球内表面的络合作用，这些官能团对配位球的参与程度与溶液pH有很大关系。在温和的碱性条件下，-NH2基团的作用更大，从而导致模拟海水中铀的萃取率很高。(C) 2017 Elsevier B.V.版权所有
Aiming at the efficient and convenient treatment of radioactive wastewater, a graphene oxide-chitosan aerogel (GO-CS) was fabricated and utilized for uranium(VI) elimination. The adsorption of U(VI) on the aerogel was evaluated as a function of contact time, solution pH, ionic strength, initial uranium concentration, and competing metal ions. High adsorption capacity for the uranium could be achieved over a wide pH range, e.g., 200, 319.9, and 384.6 mg/g at pH 3.5, 5.0, and 8.3, respectively. The interaction mechanism of U(VI) with GO-CS was systematically clarified by using Fourier transformation infrared (FT-IR), X-ray photoelectron spectroscopy (XPS), and extended X-ray absorption fine structure spectroscopy (EXAFS). It was found that the U(VI) adsorption was mainly ascribed to the inner-sphere surface complexation by -COO , -OH, and -NH2 groups anchored on the GO-CS and the involvement of these functional groups toward the coordination sphere was largely relevant to solution pH. At mild alkaline pH, -NH2 groups play a more important role, therefore leading to an extraordinarily high extraction of uranium from simulated seawater. (C) 2017 Elsevier B.V. All rights reserved.