基于MoS_(2)纳米花的表面离子印迹材料的制备及性能

Preparation and Properties of Surface Ion Imprinted Material Based on Molybdenum Disulfide Nanoflowers

以镉离子做模板离子,以多巴胺为功能单体和交联剂,通过多巴胺的自聚合反应,在二硫化钼(MoS_(2))纳米花的表面形成一薄层镉离子印迹聚合物。通过扫描电子显微镜(SEM)、傅里叶变换红外光谱仪(FT-IR)、X射线粉末衍射仪(XRD)、热重分析仪(TGA)以及比表面和孔径分布分析等表征了离子印迹材料(IIM)的形貌和结构,确证了印迹聚合层的生成。平衡吸附实验结果表明,由于IIM的印迹位点位于MoS_(2)纳米花的表面,可接触性好,因而IIM对镉离子结合速度快,吸附25 min即可达到平衡。同时,该印迹材料具有很好的印迹效果(印迹因子为6.877),对镉离子有很强的特异性识别能力,特异性结合量为518.1μmol/g。Scatchard模型分析表明印迹材料的结合位点对镉离子的亲和力不是均一的,可以分为高亲和力和低亲和力两部分。吸附等温模型分析表明,印迹材料对镉离子的吸附行为符合Langmuir吸附等温模型,由该模型可以计算出其对镉离子的最大吸附量为1081.0μmol/g。本研究为制备对重金属离子具有高选择性吸附能力的印迹材料提供了一种简单、可靠的方法。

In the present work,a thin layer of Cd(Ⅱ) ion imprinted polymer is fabricated on the surfaces of molybdenum disulfide nanoflowers through the self-polymerization of dopamine by using Cd(Ⅱ) ion as the template,dopamine as the functional monomer and cross-linker.The morphology and structure of the prepared ion-imprinted material(IIM) are charactterized by scanning electron microscopy(SEM),infrared spectroscopy(IR),X-ray diffraction(XRD),N_(2) adsorption-desorption analysis and thermal gravimetric analysis(TGA).Results of binding experiments show that IIM has a high imprinting effect(the imprinting factor is 6.877) and high specific recognition ability for Cd(Ⅱ) ion.The specific binding capacity is 518.1 μmol/g.IIM also has a fast binding rate because the imprinted sites of IIM has good accessibility for Cd(Ⅱ) ion.The time needed to reach equilibrium binding is 25 min.Scatchard plot analysis reveals that the binding sites of IIM are heterogeneous with respect to the affinity for Cd(Ⅱ) ion and could be classified into two groups,i.e.,the higher-affinity portion and the lower-affinity portion.In addition,the adsorption behavior of IIM for Cd(Ⅱ) ion is in line with the Langmuir isotherm adsorption model and the maximum adsorption capacity is determined through this model and is found to be 1081 μmol/g.The present study has provided a new convenient and reliable approach for preparation of imprinted material with high recognition ability for target heavy metal ion.