Fabrication and CO2 separation performance of carbon membranes doped with TiO2 nanoparticles
-
摘要:
以钛酸丁酯为原料、聚乙二醇为稳定剂,采用溶胶—凝胶法制备含球形 TiO2 纳米粒子的溶胶,将其与碳前驱体聚糠醇均匀混合后涂敷于多孔 Al 2O3 基体表面,最后经炭化处理制得 TiO2 -C/ Al 2O3 复合膜。 采用 SEM、TEM、XRD、粒径分析等手段对样品进行表征,并测定炭膜对 CO2 、N2 和 CH4 的渗透性能。 结果表明,聚乙二醇能有效控制钛酸丁酯的水解,不仅有利于形成粒径小而均匀的球形纳米 TiO2 粒子,而且可促进 TiO2 粒子在聚糠醇中的均匀分散。 TiO2 粒子的掺杂明显提高了炭膜的 CO2 渗透率及渗透选择性。 其中,CO2 渗透率、CO2 / N2 选择性和 CO2 / CH4 选择性分别可达 7. 0 ×10 -8 mol·m -2·s -1· Pa -1 、34 和 64。 TiO2 的掺杂有利于产生更多渗透通道,但也会阻断炭材料本身的渗透通道,因此 TiO2 的掺杂量存在最佳范围。
Abstract:A TiO2 sol was prepared from tetrabutyltitanate using polyethylene glycol as a stabilizer, and this was homogeneously mixed with polyfurfuryl alcohol, dip-coated on a porous Al 2O3 substrate and carbonized at 700°C for 4h to produce TiO2-doped carbon membranes. SEM, TEM, XRD and granulometry were used to characterize the membranes, and their permeation performance for CO2 , N2 and CH4 were tested. It was found that polyethylene glycol is effective in controlling the hydroxylation of the tetrabu-tyltitanate. This not only favored the formation of spherical TiO2 nanoparticles with a small size and narrow size distribution but also improved the homogeneity of the dispersion of the TiO2 nanoparticles in polyfurfuryl alcohol. The doping of the membranes with TiO2 nanoparticles greatly improved the CO2 permeance and permselectivity. The TiO2 doping helps to create diffusion paths, but it may also block the pores in the carbon matrix. Therefore, the CO2 permeance reached a maximum of 7. 0×10 -8 mol·m -2·s -1·Pa -1 with a mass ratio of TiO2 sol to polyfurfuryl alcohol of 2, where the CO2 / N2 and the CO2 / CH4 selectivities were 34 and 64, respectively.
-
Key words:
- Carbon membranes /
- TiO2 nanoparticles /
- CO2 separation /
- Sol-gel method /
- Doping
计量
- 文章访问数: 761
- HTML全文浏览量: 46
- PDF下载量: 836
- 被引次数: 0