纯硅MFI型分子筛膜的原位合成及其CO_2/N_2混合气体分离性能研究  

Fabrication of silica-MFI zeolite membranes for separation of CO_2/N_2 gas mixture

作　　者：张宝泉[1] 孙亮[1] 郑孟瑶 杨军[1] 刘秀凤[1] 

机构地区：[1]天津大学化工学院化学工程联合国家重点实验室,天津300072

出　　处：《膜科学与技术》2017年第2期26-31,共6页Membrane Science and Technology

基　　金：国家自然科学基金重点项目(21136008);海洋公益性行业科研专项经费项目(201105026)

摘　　要：通过多孔α-Al_2O_3载体的处理或修饰改变其表面物化性质,并采用原位水热晶化法合成纯硅MFI分子筛(silicalite-1)膜.SEM、XRD和接触角的检测结果表明,未经处理、经过H_2O_2处理或带有氧化锆中间层的α-Al_2O_3载体为亲水性表面,其上不能形成连续的分子筛膜层;而经过3-氯丙基三甲氧基硅烷(3-CP-TMS)、十二烷基三甲氧基硅烷(DMS)修饰或带有壳聚糖中间层的α-Al_2O_3载体为疏水性表面,其上可以形成连续、致密的分子筛膜层,用DMS修饰或带有壳聚糖中间层的α-Al_2O_3载体上形成的分子筛膜有一定的择优取向.疏水性的载体表面是形成连续纯硅MFI分子筛膜层的先决条件,而合理的H_2O/Si比是保证分子筛完全覆盖载体表面形成致密膜层的重要因素.将载体经DMS修饰后原位水热合成的纯硅MFI分子筛膜应用于CO_2/N_2混合气体分离过程表明,合成的膜对CO_2具有分离选择性.The porous a-Al2O3 substrates were treated or modified to change the surface properties. The silica-MFI zeolite membranes were synthesized on treated or modified a - AlzO3 substrates by in-situ crystallization. The experimental results by SEM, XRD and contact angle revealed that the untreated porous a-Al2O3 substrate, and that treated by using H202 or with a zirconia intermediate layer were hydrophilic, on which the continuous zeolite membrane could not be formed. While the porous a-Al2O3 substrate modified by using （3-chloropropyl）trimethoxysilane （3-CP-TMS） and dodecyltrimethoxysilane （DMS） or covered with a chitosan layer was hydrophobic, on which the continuous and dense zeolite membrane could be formed. The synthesized zeolite membrane on the porous a-Al2O3 substrate modified with DMS or covered with a chitosan layer were preferentially oriented. The hydrophobic nature of the substrate surface should be the prerequisite for synthesizing continuous zeolite membranes, at the same time, a proper H20/Si ratio would be a critical factor for the formation of a dense siliea-MFI membrane. After being applied in separation of CO2/N2 gas mixture, the MFI membrane synthesized on DMS-modified a- Key words,

关 键 词：分子筛膜 原位水热晶化 表面改性 

分 类 号：TQ051.893[化学工程]