Removal of cadmium(II) and lead(II) from aqueous solution using sulfur-functionalized silica prepared by hydrothermal-assisted grafting method
Removal of cadmium(II) and lead(II) from aqueous solution using sulfur-functionalized silica prepared by hydrothermal-assisted grafting method
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DOI：
10.1016/j.cej.2012.05.109
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发表时间：
2012-08-01
影响因子：
15.1
通讯作者：
Sun, Ting
中科院分区：
文献类型：
--
作者：
Fan, Hong-Tao;Wu, Jin-Bao;Sun, Ting
本文采用水热辅助表面接枝的方法，将二氧化硅表面的硅醇(SiOH)基团与双[3-(三乙氧基硅基)丙基]四硫化物分子进行硅烷化反应，得到了一种四硫化物功能化的二氧化硅吸附剂，并将其应用于水溶液中Cd~(2+)和Pb~(2+)的去除。用扫描电子显微镜、傅里叶变换红外光谱、N-2吸附-脱附等温线、元素分析和热重分析等手段对该吸附剂进行了表征。通过常规的间歇平衡吸附实验考察了溶液pH值、接触时间和金属离子初始浓度对吸附效果的影响。用Scatchard图分析了吸附过程的特征。结果表明，水热加热法制备的四硫化二氧化硅吸附剂的最大静态吸附容量是常规加热方法的1.5倍。其对Cd~(2+)和Pb~(2+)的饱和吸附容量分别达到22.3和46.3 mg·g~(-1)。四硫基官能化二氧化硅吸附剂在pH 3.7-8.5范围内具有良好的结合能力。Scatchard分析表明形成了两类结合位点。拟二级动力学模型提供了很好的动力学数据拟合(r(2)>；0.99)。平衡数据符合朗缪尔等温线模型。Delta G度、Delta H度和Delta S度等热力学参数表明，吸附是吸热自发过程。此外，四硫化物功能化二氧化硅吸附剂的吸附/脱附周期可达5次。这些结果证实了四硫基官能化二氧化硅吸附剂可能是一种潜在的脱除水溶液中Cd~(2+)和Pb~(2+)的吸附剂。(C)爱思唯尔出版的2012年。
In this paper, silanol (SiOH) groups on the surface of silica were functionalized by the silylation reactions with bis[3-(triethoxysilyl)propyl]tetrasulfide molecules using a hydrothermal-assisted surface grafting method to give a tetrasulfide-functionalized silica sorbent, which was applied to the removal of Cd2+ and Pb2+ ions from aqueous solutions. The sorbent was characterized by scanning electron microscopy, fourier-transform infrared spectroscopy, N-2 adsorption-desorption isotherms, elemental analysis and thermogravimetric analysis. The effects of pH values of solution, the contact time and the initial concentrations of metal ions were investigated by conventional batch equilibrium adsorption test. The characteristics of the adsorption process were investigated by Scatchard plot analysis. The results showed that the maximum static adsorption capacity of tetrasulfide-functionalized silica sorbent by hydrothermal heating method was 1.5 times as much as by the conventional heating method. The experimental values of the saturated adsorption capacities of Cd2+ and Pb2+ could reach to 22.3 and 46.3 mg g(-1), respectively. The tetrasulfide-functionalized silica sorbent had a substantial binding capacity in the range of pH 3.7-8.5. Scatchard analysis revealed that two classes of binding sites were formed. The pseudo second-order kinetic model provided excellent kinetic data fitting (r(2) > 0.99). Equilibrium data Equilibrium data fitted to the Langmuir isotherm model. Various thermodynamic parameters such as Delta G degrees, Delta H degrees and Delta S degrees revealed that the adsorption was endothermic and spontaneous process. In addition, the adsorption/desorption cycle of tetrasulfide-functionalized silica sorbent could be up to five times. These results confirmed that tetrasulfide-functionalized silica sorbent could be a potential sorbent for the removal of Cd2+ and Pb2+ from aqueous solutions. (C) 2012 Published by Elsevier B.V.