Ceramic Composite Membranes Based on Bi_3Ru_3O_(11)-Bi_(1.6)Er_(0.4)O_3 for Obtaining of Oxygen

摘要

Using hot uniaxial pressing in an argon atmosphere with a stress of 35 MPa and with holding at 800°C for 1 h, ceramic composites of Bi_(3)Ru_(3)O_(11)–50 wt % Bi_(1.6)Er_(0.4)O_(3)and Bi_(3)Ru_(3)O_(11)–65 wt % Bi_(1.6)Er_(0.4)O_(3)were obtained. It was found that phase composition of the composites does not change during gas chromatographic testing at 800°C and corresponds well to the specified one. The microstructure of the obtained composites was tested, and the formation of dense composites with a total porosity of less than 1% and with a uniform distribution of the Bi_(3)Ru_(3)O_(11)and Bi_(1.6)Er_(0.4)O_(3)components in the bulk of material was demonstrated. Transport properties (total conductivity, oxygen fluxes, and selectivity of separating oxygen over nitrogen) of the obtained composites at 600–800°C was investigated. Thus, at 800°C, the electrical conductivity of Bi_(3)Ru_(3)O_(11)–50?wt % Bi_(1.6)Er_(0.4)O_(3)and Bi_(3)Ru_(3)O_(11)–65 wt % Bi_(1.6)Er_(0.4)O_(3)was about 200 and 50 Ω~(–1)cm~(–1), respectively, while the metallic nature of their temperature dependence of conductivity is correlated to that for Bi_(3)Ru_(3)O_(11). The value of oxygen permeability for the obtained ceramic composites of about 7 × 10~(–9)mol cm~(–1)s~(–1)at 800°C, which is comparable to other membrane materials based on bismuth oxide, demonstrated the potential of their further use in the tasks for obtaining of pure oxygen from the air.