3 years ago

Preparation and Gas Permeation Properties of Fluorine–Silica Membranes with Controlled Amorphous Silica Structures: Effect of Fluorine Source and Calcination Temperature on Network Size

Preparation and Gas Permeation Properties of Fluorine–Silica Membranes with Controlled Amorphous Silica Structures: Effect of Fluorine Source and Calcination Temperature on Network Size
Tatsuya Okubo, Hiroki Nagasawa, Takuya Matsutani, Toshinori Tsuru, Toru Wakihara, Masakoto Kanezashi
Triethoxyfluorosilane (TEFS), which is a pendant-type alkoxysilane with a Si–F bond, was utilized for the development of a molecular sieving membrane. The effect that a source of fluorine and calcination temperature exerted on gas permeation properties and network pore size was evaluated via single-gas permeation properties across a wide range of temperatures. A TEFS membrane calcined at 350 °C showed high H2 permeance (2.0 × 10–6 mol m–2 s–1 Pa–1) and high selectivity for H2 over larger molecules (H2/CF4: >300; H2/SF6: >18 000), indicating that this network pore size would be suitable for a H2 permselective membrane that could promote the process of methylcyclohexane (MCH) dehydrogenation to produce toluene (TOL). Based on the gas permeation properties and the results of XPS and FTIR, network pore size depended on the fluorine concentration incorporated in SiO2 that existed as Si–F bonds, irrespective of the fluorine source. A TEFS membrane showed approximately the same pore size distribution and level of gas permeance, irrespective of calcination temperature (350 and 550 °C), due to the low Si–OH density in the networks as suggested by the result of FTIR, which can prevent the densification caused by the condensation of Si–OH groups. The pair distribution function also suggested that densification of the network structure for TEFS was apparently suppressed compared with that of a tetraethoxysilane (TEOS)-derived structure.

Publisher URL: http://dx.doi.org/10.1021/acsami.7b06800

DOI: 10.1021/acsami.7b06800

You might also like
Discover & Discuss Important Research

Keeping up-to-date with research can feel impossible, with papers being published faster than you'll ever be able to read them. That's where Researcher comes in: we're simplifying discovery and making important discussions happen. With over 19,000 sources, including peer-reviewed journals, preprints, blogs, universities, podcasts and Live events across 10 research areas, you'll never miss what's important to you. It's like social media, but better. Oh, and we should mention - it's free.

  • Download from Google Play
  • Download from App Store
  • Download from AppInChina

Researcher displays publicly available abstracts and doesn’t host any full article content. If the content is open access, we will direct clicks from the abstracts to the publisher website and display the PDF copy on our platform. Clicks to view the full text will be directed to the publisher website, where only users with subscriptions or access through their institution are able to view the full article.