Ceramic
membrane
technology

This work focused on the fabrication of a ZrO2/SiC ultrafiltration membrane by dip coating a high porous SiC support with a ZrO2 slurry prepared by ceramic processing. The membranes were sintered in different temperatures (1000−1300 °C). With the optimal temperature, it was obtained a mechanically strong, homogenous, and defect free separation layer with 45 μm of thickness and average pore size of 60 nm. A pure water permeability of 360 L.m−2 h−1 bar-1 and high retentions of humic acid, indigo dye, and hemoglobin were observed. In a pilot test with an olive oil/water emulsion, 99.91 % of oil was removed without fouling. Long-term corrosion tests at basic and acid baths did not cause change in pore size and morphology. In conclusion, the ZrO2/SiC membrane has potential to operate in harsh conditions (e.g. heavily contaminated industrial effluents or urban wastewaters) and when severe membrane cleaning and disinfection are required, such as food and pharmaceutical industries.

Water scarcity and water pollution are major issues in today’s world. Several industries including oil and gas, water treatment, wastewater treatment, and food and beverage processing have turned their attention to silicon carbide membranes to solve these issues, due to the increased water flux and enhanced mechanical, chemical, and thermal stability observed for this material. To shift the material dominance on the membrane market from polymeric and ceramic oxide to silicon carbide, a deep understanding of the fabrication of silicon carbide membranes is important. Therefore, this review focuses on the development of silicon carbide membranes from an industrial standpoint. The discussed approaches include the deposition of colloidal suspensions and polymeric precursors. In addition to describing the significant steps in the fabrication of silicon carbide membranes, the advantages, disadvantages, and remaining key challenges related to these approaches are emphasized. Furthermore, key aspects in the preparation of silicon carbide supports are presented to provide an understanding of how membrane support influences membrane performance. The wide range of silicon carbide membrane applications in water and wastewater treatment and other applications are then reviewed. Cleaning methods for silicon carbide membranes are also described to address fouling issues during filtration processes along with commercialization of these membranes. Finally, future perspectives on silicon carbide membrane material development and potential applications in other industrial sectors are discussed. Overall, this review paper aims to provide a roadmap for potential applications and further development of silicon carbide membranes in the field of liquid filtration.

An environmental-friendly procedure has been developed for the fabrication of pure silicon carbide membranes on macroporous SiC support via ceramic processing. Water dispersions of α-SiC powders were used for deposition of membrane layers by dip-coating. The influence of the fine/coarse powder mixing ratio, solid loading, use of α-SiC powders with different particle sizes as well as sintering temperature on the structural morphology of the membranes were investigated in order to obtain uniform, homogeneous, and defect-free SiC membrane layers. The optimized protocol was up-scaled on industrial SiC tubular supports with high reproducibility, reducing the sintering temperature compared to conventional SiC membrane synthesis. The new SiC membranes were used for the treatment of a secondary effluent from Biofos wastewater treatment plant in Avedøre, Denmark, and their performances evaluated in terms of removal of the suspended solids, colloidal particles and reduction of chemical oxygen demand. According to filtration results, the new SiC membranes showed high removal of suspended solids (99.4%) and colloidal particles (96%) along with significant reduction of chemical oxygen demand (83%). The pure SiC membranes developed in this study have a potential to be applied in the wastewater treatment since they combine the robustness of SiC with high selectivity.