Enhanced fabrication of silicon carbide membranes for wastewater treatment: From laboratory to industrial scale

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.