Silicon carbide ceramic membrane support sintered at 800 °C with low-temperature sintering aid

Silicon carbide ceramic membranes have been widely used in the treatment of various corrosive and high temperature wastewaters. However, SiC is a compound with strong covalent bond, thus the sintering temperature and then the energy consumption during sintering of SiC ceramics is high, which inhibits the scale-up manufacturing of SiC ceramic membranes. Here, a silicon carbide ceramic membrane support was prepared at 800 °C with a low melting-point glaze as the sintering aid. The glaze infiltrated the SiC skeleton during sintering, and gave rise to high fracture strength of the porous ceramics. With the content increase of sintering aid from 10 wt% to 30 wt%, the pore-formation mechanism of the ceramic membrane support transformed from SiC particles packing to SiC aggregations packing, leading to the increase in pore size and decrease in porosity. The permeance and selectivity of the support was investigated via pure-water and oil-in-water emulsion tests. Due to the high hydrophilicity, the pure-water flux increased from 32 L/(m2·h) to 87 L/(m2·h) while the oil rejection decreased from 99.0% to 93.1% with the increase of trans-membrane pressure. This work provides a feasible route for the preparation of SiC porous ceramics with low energy consumption.