以正硅酸乙酯为硅源,采用溶胶-凝胶法,通过调整合成体系pH与温度控制正硅酸乙酯的水解与缩聚过程,制备出4种不同孔径分布的介孔二氧化硅。以X射线衍射（XRD）、透射电镜（TEM）、N₂吸附-脱附、程序升温脱附（NH₃-TPD）、傅里叶红外光谱（FTIR）、热重（TG）等表征手段对二氧化硅物化性质进行表征,并考察4种介孔二氧化硅的烷/烯吸附分离性能。结果表明,介孔二氧化硅的硅羟基种类以自由羟基为主,随着合成终点pH增加,孔径增加,比表面积减少,硅羟基浓度降低,酸量减少,酸强度增加;孔径分布及酸性质对吸附分离性能影响明显,平均孔径为4.9 nm样品的酸强度适宜,分离度R_烷/烯>1,烯烃脱附速度快,吸/脱附速率比接近1,是较为理想的烷/烯分离吸附剂。

Four kinds of mesoporous silica with different pore size distribution were prepared by sol-gel method by using the tetraethyl orthosilicate as silica source,by adjusting the pH and temperature of the synthesis system to control the hydrolysis and condensation process of tetraethyl orthosilicate.The physicochemical properties of silica were characterized by X-ray diffraction（XRD）,transmission electron microscopy（TEM）,N₂ adsorption desorption,program temperaturerise desorption （NH₃-TPD）,Fourier infrared spectroscopy（FTIR） and thermal gravity（TG） technology.The alkane/olefin adsorption/separa-tion properties of four kinds of silica were investigated.The results showed that the hydroxyl groups of mesoporous silica were mainly free hydroxyl groups.With the increase of synthetic end point pH,silica gel′s pore volume and pore size increased,the specific surface area,the concentration of silicon hydroxyl and the acid content decreased,the acid intensity increased.The pore size distribution and acid properties had obvious influence on adsorption and separation performance.The samples with average pore size of 4.9 nm had suitable acid intensity,the separation degree ofR_{alkane/olefin} was above 1,the desorption rate of alkene was fast,with the ratio of absorption/desorption rate close to 1,which was found to be an ideal adsorbent for alkane/olefin separation.