Processing and microstructure-permeation properties of silica bonded silicon carbide ceramic membrane

Porous SiC is a valuable membrane material for the microfiltration and ultrafiltration of various wastewaters because of its high hydrophilicity and low fouling tendency, but its preparation has been limited by the high sintering temperature. Here, a silica bonded silicon carbide membrane was prepared by the oxidation of SiC at low temperature. When the SiC substrates were sintered in the temperature range from 1200 to 1400 degrees C, their porosity decreased from 45 % to 37 % while the flexural strength increased from 45 to 59 MPa. For the selective layers made from SiC particles with 0.5 mu m in diameter, the average pore sizes that sintered at 1050 and 1150 degrees C were 0.34 and 0.26 mu m, respectively, corresponding to the water fluxes of 1080 and 1240 L/(m2 h, respectively. Thus, this technique provided a cost-effective path to prepare ceramic membrane at low sintering temperature.

Automated summary

The study prepared a silica bonded silicon carbide membrane by oxidizing SiC at low temperature, which has high flexural strength and low porosity, suitable for microfiltration and ultrafiltration of wastewaters. It was found that the porosity of the SiC substrates decreased while the flexural strength increased when sintered in the temperature range of 1200 to 1400 degrees Celsius.