憎水性二氧化硅膜的制备及其气体分离性能研究

STUDY ON THE PREPARATION AND GAS SEPARATION PERFORMANCE OF HYDROPHOBIC SILICA MEMBRANES

采用甲基三乙氧基硅烷(MTES)通过溶胶-凝胶法制备了憎水性Si O2膜并进行了气体分离实验.实验结果表明,随着MTES的加入,接触角从32.76°增大到改性后的98.16°,在潮湿空气中放置90天,膜的憎水性仍能够保持;MTES/TEOS=0.8时,薄膜的憎水性可以保持到400℃.气体渗透实验表明,在0.1 MPa下,循环焙烧3次后N2的渗透通量为0.44×10-7mol.m-2.Pa-1.s-1,CO2的渗透通量为0.45×10-7mol.m-2.Pa-1.s-1,H2的渗透通量为1.90×10-7mol.m-2.Pa-1.s-1.H2/N2的分离因子为4.32,H2/CO2的分离因子为4.22,焙烧3次后气体渗透已经有了超越努森扩散机理的趋势,膜孔结构比较稳定,所制Si O2膜具有较好的耐水汽性能.

Methyl-modified silica membranes were prepared by added methyl-tri-ethoxy-silane （MTES） by Sol-Gel process. With the adding of MTES/TEOS, the silica membranes were characterized by IR and the measurement of contact angle, we found that the contact angle was 98.16° of modified membrane, and the unmodified membrane was 32.76°. The hydrophobicity of modified silica membranes could maintain 90 days. The effect of calcinations temperature on the hydrophobicity of modified silica could keep hydrophobic at temperature 400 ℃ with the MTES/TEOS molar ratio of 0.8. Gas separation experiment showed that when dipping-calcination process was circulated for three times and the system was at a pressure of 0.1 MPa, the gas permeance of N2 ,CO2 ,H2 was 0.44×10^- 7 mol ·m^-2 · Pa^-1 · s 1, 0.45×10^-7 mol · m^-2 ·Pa^-1·s^- 1 and 1. 90×10^-7 mol· m^-2· Pa^-1· s^-1,respectively. The H2/N2 separation factor was 4. 32 and the H2/CO2 separation factor was 4. 22. It showed that the pore structure was stable and this modified silica membrane bah good property of hydrophobicity.