Efficient strategies for engineering high-permeance SiC ceramic membranes for gas/solid filtration: Prefilling method

The trade-off between gas permeance and filtration accuracy in SiC ceramic membranes has constrained their utilization in gas/solid filtration. Herein, a polyvinyl butyraldehyde (PVB) solution was introduced as a prefilling layer to impede membrane particles from penetrating the macroporous SiC support (average pore size: 23 mu m). The PVB layer could be removed postsintering, thereby producing a ceramic membrane devoid of any intermediate layer, which showed great potential in enhancing the gas permeance. Initially, the PVB concentration was optimized to ensure membrane integrity and strong adhesion between the support and separation layer. Thereafter, suitable dispersants and drying conditions were investigated in detail. The resultant asymmetric SiC membranes fabricated under these optimized conditions had a thickness ranging between 50 and 60 mu m. These membranes demonstrated exceptional gas permeance, varying from 71.1 to 178.1 m3 m-2 h-1 kPa- 1 by tuning the membrane pore size from 1.02 to 3.03 mu m. Additionally, the membranes achieved 99.94 % dust rejection for particles approximately 0.3 mu m in size. When compared to traditional ceramic membranes with several intermediate layers, the prefilling approach employed herein circumvents the ceramic intermediate layer. This method resolves the mismatch between particle sizes of the ceramic support and the membrane layer, offering an effective strategy for developing high-permeance SiC membranes suited for gas/solid filtration applications.