Novel interface enhancement strategy enables SiC fiber membrane for high-temperature gas/solid filtration

The high gas permeance of ceramic membranes is the most important indicator of hot-gas filtration. Ceramic membranes made of fibers show significant potential for filtering dust-laden gases owing to their high porosity and high gas permeance. A novel method is proposed for preparing a SiC fiber separation layer on a rigid ceramic support that endows the membrane with a high porosity. However, the interfacial adhesion between the support and separation layers was low as there were insufficient connection points. Therefore, a solvothermal method was proposed for the in-situ vertical growth of TiO2 nanocords on the surface of a SiC support (SiC-TiO2). Next, a SiC fiber separation layer was deposited on the SiC-TiO2 support to improve the interfacial adherence. The fabrication parameters of the SiC fiber layer, such as the solid content of the coating slurry and sintering pro-cedure of the separating layer, were investigated in detail. At a SiC fiber content of 6 wt%, spray-coating times of 2, and sintering temperature of 1150 degrees C, a complete fiber layer was successfully deposited on the rigid ceramic support. The resulting membrane had a thickness of 100 & mu;m, porosity of 91%, average pore diameter of 6.8 & mu;m, and gas permeance of 440 m3 & BULL;m- 2 & BULL;h-1 & BULL;kPa- 1. In the filtration of dust-laden gas containing SiO2 as simulated dust (average particle size, 0.3 & mu;m), the rejection rate was >99.9%; further, after four cycles of fil-tration-backwashing, the pressure drop was <0.82 kPa. The outlet dust content was less than 0.1 mg m- 3. Moreover, this membrane exhibited superior filtration ability at 500 C. The findings of this study can aid the fabrication of ceramic fiber membranes with a high gas permeance and high interfacial adherence for industrial applications.

Automated summary

Ceramic membranes made of fibers have high gas permeance and can be used for filtering dust-laden gases. A novel method of preparing a SiC fiber separation layer on a ceramic support was proposed to increase the porosity of the membrane. The interfacial adhesion between the support and separation layers was improved by vertically growing TiO2 nanocords on the support.