Premium
Hydrothermal stability of fluorine‐induced microporous silica membranes: Effect of steam treatment conditions
Author(s) -
Kanezashi Masakoto,
Hataoka Naoya,
Ikram Rana,
Nagasawa Hiroki,
Tsuru Toshinori
Publication year - 2021
Publication title -
aiche journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.958
H-Index - 167
eISSN - 1547-5905
pISSN - 0001-1541
DOI - 10.1002/aic.17292
Subject(s) - permeance , microporous material , membrane , chemistry , hydrothermal circulation , calcination , chemical engineering , superheated steam , nuclear chemistry , organic chemistry , waste management , catalysis , permeation , biochemistry , engineering , boiler (water heating)
A fluorine‐SiO 2 membrane was prepared using triethoxyfluorosilane (TEFS) as a Si precursor, and its hydrothermal stability was evaluated. The TEFS membrane calcined at 750°C had fewer Si‐OH and Si‐F groups in its network structure and showed H 2 permeance that was greater than 10 −6 mol m −2 s −1 Pa −1 with H 2 /N 2 and N 2 /SF 6 permeance ratios of 10 and 210, respectively. This membrane performance was relatively stable under the temperature (< 500°C) used for steam treatment, regardless of the steam partial pressure (30, 90 kPa). On the other hand, when the steam treatment temperature was increased beyond 500°C, gas permeance decreased significantly and the membrane became highly selective for He and H 2 over smaller molecules (He/N 2 : > 600, H 2 /N 2 : > 100). The relationship between the activation energy of H 2 and the permeance ratios (He/H 2 , He/H 2 O, H 2 /H 2 O) of a TEFS‐derived membrane under steam treatment higher than 600°C resulted in a network pore size that approximated in conventional microporous SiO 2 membranes.