金属离子掺杂硅胶吸附剂的性能与结构表征

CHARACTERIZATION AND PERFORMANCE OF METALLIC DOPED SILICA GEL ADSORBENT

以陶瓷纤维纸为基材,钴盐、铝盐或钛盐为改性剂,顺次经水玻璃、酸性盐溶液浸渍共沉积制得金属离子掺杂硅胶吸附剂。采用扫描电镜、多孔介质空隙分析仪、光电子能谱仪表征改性吸附剂组成、表面形貌、孔径大小及分布;用程序升温脱附谱,热失重分析仪等检测材料的脱附性能及热稳定性。结果表明:金属离子掺杂硅胶均匀分布在陶瓷纤维纸表面及其空隙中;经掺杂后的硅胶,其吸附性能、Brunauer-Emmett-Teller(BET)比表面积、孔容、平均孔径明显增加。改性硅胶的BET表面积、饱和吸附量及热稳定性按照铝掺杂硅胶、钛掺杂硅胶、钴掺杂硅胶及硅胶的顺序递减。

Using cobalt salt,aluminum salt or titanium salt as modifying agents,the metallic doped silica gel adsorbents based on ceramic fiber paper were prepared by treating ceramic fiber paper with sequential impregnation coprecipitation of water glass and aqueous solution of acidic metallic-salt.The composition,surface structure,pore size and distribution of the doped silica gel adsorbents were characterized by scanning electron microscopy,porous medium analyzer and X-ray photoelectron spectroscopy.Temperature programmed desorption spectrum and thermogravimetric analysis were used to evaluate the desorption performance and the thermal stability of the modified silica gel adsorbents.The results show that metallic doped silica gel well scattered on the surface and in the apertures of the ceramic fiber paper.As a result of the metallic ion-doping,the adsorptive capacity,Brunauer-Emmett-Teller （BET） surface area,the total pore volume and the average pore diameter of the modified silica gel all increase.The saturated adsorptive capacity,the BET surface area and the thermal stability of modifying silica geles decrease according to Al-doped silica gel,Ti-doped silica gel,Co-doped silica gel and silica gel,respectively.