Permeation properties of BTESE-TEOS organosilica membranes and application to O2/SO2 gas separation

In the present study, a BTESE-TEOS mixed precursor was proposed for control of the pore sizes of organosilica networks in organic-inorganic hybrid silica membranes. FT-IR spectrometry confirmed the formation of a partially cross-linked polysiloxane structure with hydrocarbon units in a BTESE-TEOS-derived silica network produced by the co-hydrolysis and condensation of BTESE with TEOS, which also showed an improved thermal stability. Single gas permeation measurements and normalized Knudsen-based permeance (NKP) established the order of the average membrane pore sizes as follows: BTESE > BTESE-TEOS > TEOS. The organosilica membranes derived from BTESE-TEOS exhibited a superior O-2 permeance that was higher than 10(-8) mol m(-2) s(-1) Pa-1 with an O-2/SO2 selectivity of 7.3, which indicated that the pore size control in organosilica networks using BTESE-TEOS as a precursor was effective for selective O-2/SO2 separation. Moreover, the effective molecular size of SO2 permeates through organosilica membranes was discussed. (C) 2015 Elsevier B.V. All rights reserved