调控介孔硅分子筛的孔壁结构以提高吸附亚硝胺的效率

Modification of Structure of Pore Wall of Mesoporous Aluminosilicate to Increase Its Adsorptive Capability for Nitrosamine

针对高空速下捕获痕量毒物分子的环境净化要求,尝试调控介孔材料孔壁结构以提高其吸附小分子环境污染物的效率.通过调节合成体系的pH值、加入无机盐以及控制表面活性剂浓度等方法,改变硅物种与模板剂胶束的组装速度或无机-有机液晶相的存在形态,研制含有孔壁缺陷位的介孔分子筛新材料.通过X射线衍射和低温氮气吸附研究了样品的结构特性,并采用高分辨透射电镜和固体核磁技术证实了介孔材料孔壁缺陷位的形成.以挥发性吡咯烷亚硝胺为靶标分子,考察了所得材料的吸附性能.结果表明,大量缺陷空位的存在成倍地提高了介孔分子筛吸附挥发性亚硝胺的效率,为设计研制环保新材料提供了新思路.

A method to control the structure of the silica wall of mesoporous silica materials was proposed for trapping trace amounts of small pollutant molecules. The mesoporous silica materials containing pore wall defect voids were synthesized by controlling the pH of the synthesis system and the concentration of the organic surfactant and adding an inorganic salt to control the assembling rate of silica species on the surfactant micelle or change the form of the surfactant-aluminosilicate liquid crystal. X-ray diffraction, N2 adsorption-desorption, ^29Si MAS nuclear magnetic resonance, and transmission electron microscopy were used to characterize the pore structure of the samples. Volatile nitrosamine N-nitrosopyrrolidine （NPYR） was selected as the probe to assess the adsorptive capacity of the composites. The introduction of aluminum species and the creation of structural defects in the mesoporous silica wall greatly improved the adsorption of NPYR. The material is useful for environmental protection.