Efficient construction of SiC membranes to filtrate high-temperature dust-laden gas for environmental sustainability

During the production processes of energy, metallurgy, chemical engineering, and other process industries, substantial high-temperature dust-laden flue gas is generated. Asymmetric silicon carbide (SiC) membranes exhibit significant potential in flue gas filtration since they enable direct filtration of high-temperature gas and facilitate thermal energy recovery. However, membrane particle penetration is a prevalent issue when constructing membrane layer directly on macroporous support, which contributes to a considerable mass transfer resistance. Herein, a novel hydrophobic modification strategy was developed to avoid the slurry penetration, thereby fabricating the asymmetric SiC membrane without the necessity of any intermediate or sacrificial layer. Firstly, the modifier concentration was adjusted to guarantee that the support was hydrophobic enough to prevent the slurry from penetrating. Subsequently, the slurry surface tension was fine-tuned by introducing ethanol to enhance the integrity of the SiC membrane. Furthermore, the effect of solid content was systematically investigated. It was demonstrated that the optimized SiC membranes obtained excellent gas permeance from 100.8 to 199.8 m³·m⁻²·h⁻¹·kPa⁻¹ with the pore size ranging from 1.93 to 3.89 μm. Also, the SiC membrane exhibited excellent stability for 24 h and achieved an excellent dust removal efficiency (99.99%) when filtering ultrafine dust particles (∼300 nm) under high temperatures. This method effectively bridges the membrane particle penetration issue caused by the particle size disparity among different layers of the asymmetric membrane, establishing an efficient strategy to fabricate high-permeance SiC membranes applied in high-temperature dust-laden gas filtration.