Al₂O₃和SiC微滤膜的疏水改性及其油固分离性能研究

The Al₂O₃ film and the SiC film with an average pore diameter of 500 nm were hydrophobically modified by n-octyltriethoxysilane and ethanol as modifiers and solvents, respectively. The concentration and modification of the modifer were investigated by graft polymerization. The wettability and oil-solid separation performance of the modified Al₂O₃ and SiC MF membranes were investigated. The backflushing operation and long-term stability test for the modified membranes were conducted. Under the optimal modification conditions with grafting agent concentration of 0.2 mol•L^-1, grafting temperature of 40℃ and grafting time of 12 h,the water contact angles (WCAs) of the modified Al₂O₃ and SiC membranes were as high as 134°±1°and 140°±1°, respectively. It was found that the hydrophobic SiC membrane showed higher hydrophobicity than that of the Al₂O₃ membrane. For oil-solid separation experiments, both modified membranes exhibited excellent rejection to impurities in oil phase. However, the hydrophobic modification had a more significant effect on the flux of SiC membrane. The fluxes of hydrophobic Al₂O₃ and SiC MF membranes were 1134 L•m^-2•h^-1 and 1408 L•m^-2•h^-1, respectively, with transmembrane pressure of 0.25 MPa. Backflushing operation was beneficial to the flux recovery of ceramic membrane, especially hydrophobic SiC membrane.