Preparation and characterization of a mesoporous polycrown impregnated silica and its adsorption for palladium from highly acid medium
Preparation and characterization of a mesoporous polycrown impregnated silica and its adsorption for palladium from highly acid medium
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DOI：
10.1007/s10934-016-0343-4
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发表时间：
2017-08
影响因子：
2.6
通讯作者：
Ying Dai;Yan Liu;A. Zhang
中科院分区：
文献类型：
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作者：
Ying Dai;Yan Liu;A. Zhang
首先通过将多冠浸渍并固定在多孔二氧化硅中制备了多冠负载二氧化硅复合材料Polycrown/SiO2-P，并通过扫描电子显微镜（SEM）、傅里叶变换红外（FT-IR）光谱、氮气吸附和解吸等温线对其进行了表征。对 Polycrown/SiO2-P 的吸附性能进行了测试。有趣的是，与碱金属、碱土金属和锕系元素相比，Polycrown/SiO2-P 更喜欢 Pd(II)。因此研究了 Polycrown/SiO2-P 对 Pd(II) 的吸附随 HNO3 浓度、接触时间、初始 Pd(II) 浓度和温度的变化。结果表明，最佳吸附酸度为5.0 M硝酸，具有良好的耐酸性。准二级动力学模型拟合良好，表明化学吸附。 Langmuir 等温线模型很好地描述了等温吸附平衡，最大吸附容量为 14.30 mg/g。 Pd(II)吸附量随温度升高而增加。 ΔH°和ΔS°为正值，ΔG°为负值表明吸附是吸热、熵增和自发的。通过 XPS 表征了负载 Pd(II) 的 Polycrown/SiO2-P。此外，回收的Polycrown/SiO2-P的吸附效率在五个吸附解吸循环后仍保持在约93.7%。 Polycrown/SiO2-P有望从强酸性介质中分离Pd(II)。
A polycrown loaded silica composite material named Polycrown/SiO2-P was firstly prepared by impregnating and immobilizing polycrown into porous silica and was characterized by scanning electron microscope (SEM), and Fourier transformed infrared (FT-IR) spectroscopy, nitrogen adsorption and desorption isotherms. Polycrown/SiO2-P was tested with regard to adsorption performance. Interestingly, Polycrown/SiO2-P preferred Pd(II) than alkali metals, alkaline-earth metals and actinides. Pd(II) adsorption with Polycrown/SiO2-P as functions of HNO3concentration, contact time, initial Pd(II) concentration, temperature were thus investigated. The results showed the optimal adsorption acidity was determined as 5.0 M nitric acid, proving good acidity-resistant. Pseudo-second-order kinetics model fitted adsorption well indicating chemical adsorption. The isotherm adsorption equilibrium was well described by Langmuir isotherm model with maximum adsorption capacity of 14.30 mg/g. Pd(II) adsorption increased with temperature increased. The positive ΔH° and ΔS°, and the negative ΔG° indicated the adsorption was endothermic, entropy increase and spontaneous in nature. Pd(II) loaded Polycrown/SiO2-P was characterized by XPS. Further, the adsorption efficiency of recovered Polycrown/SiO2-P retained up ~93.7% after five ad-desorption cycles. Polycrown/SiO2-P was promising to separate Pd(II) from highly acid medium.