Pore size tuning of bis(triethoxysilyl)propane (BTESP)-derived membrane for gas separation: Effects of the acid molar ratio in the sol and of the calcination temperature
Pore size tuning of bis(triethoxysilyl)propane (BTESP)-derived membrane for gas separation: Effects of the acid molar ratio in the sol and of the calcination temperature
复制标题
DOI：
10.1016/j.seppur.2020.116742
复制
发表时间：
2020-07-01
影响因子：
8.6
通讯作者：
Tsuru, Toshinori
中科院分区：
文献类型：
--
作者：
Inoue, Ryota;Kanezashi, Masakoto;Tsuru, Toshinori
双(三乙氧基硅基)丙烷(BTESP)是一种具有Si-C3H6-Si键的桥联型有机烷氧基硅烷。利用它通过溶胶-凝胶法制备膜，以实现对大分子的高渗透选择性。通过分子尺寸依赖关系(0.26-0.55 nm)和温度依赖关系(50-200℃)评价了膜的制备参数，如溶胶中的酸摩尔比(AR)和焙烧温度对网络孔径和气体渗透性能的影响。不同ARs(10(-1)、10(0)和10)的BTESP膜对H-2/N-2和H-2/CF4的选择性分别为20-30和640-32,000。随着AR的增加，各气体的渗透率也增加，但对应于网络孔径的H-2选择性降低。FT-IR分析表明，未烧成的凝胶中Si-OH基团(Si-OH/Si-O-Si)的密度随AR的增大而降低，因此在AR(10(-1))较低的BTESP膜中，在焙烧过程中Si-OH基团的缩合形成了致密的网络结构。焙烧温度对BTESP膜的网络结构也有影响。在不同温度(350、450和600℃)下焙烧的BTESP膜的H-2/N-2和H-2/CF4的选择性分别为10-30和410-32,000。高温(600℃)焙烧的BTESP膜具有疏松的网状结构，因为BTESP的连接单元在500℃以上的温度下分解，从而形成甲基。总之，溶胶中的AR适合于调节小孔尺寸，而焙烧温度作为膜制备参数则为疏松的网络结构提供了可控性的优势。
Bis(triethoxysilyl)propane (BTESP) is a bridged-type organoalkoxysilane with a Si-C3H6-Si bond. It was utilized for membrane fabrication via a sol-gel method to achieve high permselectivity for large molecules. Membrane fabrication parameters such as the acid molar ratio (AR) in the sol and calcination temperature were evaluated for their effect on the network pore size and on gas permeation properties, as evaluated by the molecular size dependence (0.26-0.55 nm) and temperature dependence (50-200 degrees C) of gas permeance. BTESP membranes with different ARs (10(-1), 10(0), and 10) showed H-2/N-2 and H-2/CF4 selectivities of 20-30 and 640-32,000, respectively. As AR was increased, each gas permeance also increased, but H-2 selectivity that corresponds to network pore size was decreased. FT-IR analysis indicated that the density of the Si-OH groups (Si-OH/Si-O-Si) of unfired gels was decreased with a higher AR, so that condensation of the Si-OH groups during the calcination process formed a dense network structure in the case of BTESP membranes with a low AR (10(-1)). Calcination temperature also affected the network structure of BTESP membranes. BTESP membranes calcined at different temperatures (350, 450, and 600 degrees C) showed H-2/N-2 and H-2/CF4 selectivities of 10-30 and 410-32,000, respectively. A BTESP membrane calcined at high temperature (600 degrees C) showed loose networks since the linking units derived from BTESP were decomposed at temperatures above 500 degrees C, which resulted in the formation of methyl groups. In conclusion, the AR in a sol is suitable for tuning small pore sizes, while calcination temperature as a membrane fabrication parameter offers the advantage of controllability for loose network structures.