Tailoring the Subnano Silica Structure via Fluorine Doping for Development of Highly Permeable CO2 Separation Membranes. Issue 4 (24th February 2016)

• Record Type: Journal Article
• Authors: Kanezashi, Masakoto; Matsutani, Takuya; Wakihara, Toru; Tawarayama, Hiromasa; Nagasawa, Hiroki; Yoshioka, Tomohisa; Okubo, Tatsuya; Tsuru, Toshinori
• Is Part Of: ChemNanoMat. Volume 2:Issue 4(2016)
• Page Start: 264
• Page End: 267
• Publication Date: 2016-02-24
• Subjects: amorphous silica membranes -- CO2 separation -- fluorine doping -- molecular sieving; Nanochemistry -- Periodicals; Nanostructured materials -- Periodicals; Nanochemistry; Nanostructured materials; Periodicals; 541.2
• DOI: 10.1002/cnma.201600045
• Languages: English
• ISSNs: 2199-692X

Abstract

Abstract: The fluorine doping of a silica matrix was proposed in the design of enlarged and uniform networks for highly permeable CO2 /CH4 separation membranes. Fluorine doping effectively created a tunable network size, and the order of pore sizes increased with increases in the F concentration: F−SiO2 (F/Si=2/8)>F−SiO2 (F/Si=1/9)>SiO2 . F−SiO2 (F/Si=1/9) membranes showed high CO2 permeance (4.1×10 −7 mol m −2 s −1 Pa −1 ) with high CO2 /CH4 selectivity (≈300) at 35 °C, due to the enlarged and uniform networks compared with those of SiO2 . Fluorine doping was effective in preventing the formation of a 2nd Si−O in the 4‐membered ring (MR) of the SiO4 tetrahedra. F−SiO2 samples with smaller fractions of 4 MR and a smaller ring in silica, contain large fractions of larger rings (>5 MR), resulting in enlarged network structure and an increase in the average pore size, which translates to a higher permeance for larger molecules. Abstract : Fluorine doping of a silica matrix was proposed in the design of enlarged and uniform networks for highly permeable CO2 /CH4 separation membranes. Fluorine doping effectively created a tunable network size, and F−SiO2 (F/Si=1/9) membranes showed high CO2 permeance (4.1×10 −7 mol m −2 s −1 Pa −1 ) with high CO2 /CH4 selectivity (≈300) at 35 °C.