钛掺杂硅胶块体吸附剂

以陶瓷纤维纸片为基材,顺次经水玻璃、酸性钛盐溶液浸渍共沉淀制得新型陶瓷基钛掺杂硅胶块体吸附剂.多孔介质表面分析显示:掺杂硅胶孔径在0.5～6 nm范围,以中孔为主.Fourier变换红外谱在波数954 cm 1处的特征吸收峰表明吸附剂中形成了Si-O-Ti键.根据掺杂前后固体魔角核磁共振硅谱中硅原子化学位移的变化(向高场方向移动)及X射线光电子能谱中各原子结合能的变化(Ti2p3/2的结合能随钛含量的增加而增加,而Si2p,O1s的结合能则呈相反趋势)进一步表明:钛原子替代硅原子进入硅胶网络.热重分析及烧结实验结果显示:钛掺杂吸附剂具有更好的热稳定性.新型吸附剂优异的吸附性能除了与其高的比表面积相关外,还与Ti-O键对水分子的亲合力紧密相关,其耐热性能增强与形成高热稳定性Ti-O Si键及材料表面导热性能提高有关.

MONOLITHIC ADSORBENT OF TITANIUM-DOPED SILICA GEL

A novel Ti-doped silica gel monolithic adsorbent with a ceramic matrix was prepared by treating ceramic fiber paper with sequential impregnation of water glass, aqueous solution of acidic titanium salt, etc. The porous medium surface area analysis shows that the average pore sizes are within the range of 0.5-6 nm, and the mesopore is dominant in Ti-doped gel. In the Fourier transform infrared spectra, the peak of 954 cm^-1 is the characteristic of Si-O-Ti bond of the Ti-doped adsorbent. After being Ti-doped, the chemical shift of silica atom shifts to a higher magnetic field from ^29Si magic angle spinning nuclear magnetic resonance, and the binding energy of Ti2p32 increases with the increase of titanium content, while those of Si2p and O1s have opposite trends from X-ray photoelectron spectroscope, it can be inferred that some titanium atoms substitute for silicon atoms and insert into the silica gel framework. The thermogravimetry analysis and sintered experiment indicate the enhancement of thermal stability by Ti-doping. In the novel adsorbent, in addition to a higher the specific surface area, excellent adsorptive capacity is interrelated to the stronger hydrophilicity of Ti-O linkages to water molecules, and high thermal stability is associated with the formation of Ti-O-Si bonds and the improvement of the thermal conduction.