Gas Permeation through Zeolite-filled Silicone Rubber Membranes: Effects of Zeolites on Gas Permeabilities

• Main Authors: S.-L. Oue, 歐享霖
• Other Authors: Y.-M. Sun
• Format: Others
• Language: zh-TW
• Online Access: http://ndltd.ncl.edu.tw/handle/45073158876518345699

碩士 === 元智大學 === 化學工程研究所 === 81 === Composite membranes, consisting of PDMS polymer and three types of zeolites (ZSM-5, Mordenite, and Type-Y) were prepared. The Permeabilities and diffusivities for four gases (N2, O2, CO2, and SO2) through these membranes were determined from the steady-state and time-lag data, respectively, at different temperatures and pressures in the permeation experiments. By adding zeolites into PDMS, the diffusivities of gases in the membranes were decreased and the solubilities of gases in the membranes were increased. The effects of zeolites on diffusivities were dependent upon the pores sizes and the the structure of the zeolites. The smaller pores size of the zeolites were, the more significant the effective diffusivities of gases in the membranes would decrease. The influences of adding zeolites on membrane permeabilities were dependent upon the nature of the gases, and the mutual effects between the composite membranes and gases, and in particular the molecular sieve and sorption properties of the zeolites. The pore sizes in ZSM-5(2802) zeolite were appropriate to improve th ideal separation factor for O2/N2 mixtures. Due to the smaller pore size caused by higher Al2O3/SiO2 ratio in zeolite, adding ZSM-5(5020) could not improve the O2/N2 ideal separation factor. At lower temperatures, the permeabilities for SO2 , a more condensible gas, in ZSM-5(2802) zeolie filled membrane was batter than that in unfilled one. the ideal separation factor was improved for SO2/N2, but was unchanged for O2/N2 by adding Mordenite zeolite. Although the blocking effect of Type-Y zeolite on gas diffusivity was minimal, the gas permeabilitis still decreased in Type-Y zeolite filled membrane because the solubilities of gases were not improved much from unfilled one.