Preparation of Superhydrophilic-Superoleophobic Diatomite Porous Ceramics and Its Oil-Water Emulsion Continuous Separation Performance

Diatomite porous ceramics prepared by a foam-gelcasting route were used as a matrix, and SiO₂ microspheres in-situ formed by a solvothermal method were used to modify the surface roughness of diatomite porous ceramics. Capstone FS–50 (CS–50) was used as a modifier to prepare SiO₂ microspheres and CS–50 co-modified superhydrophilic-superoleophobic diatomite porous ceramics (SSMDPC) for the use of continuous separation of oil/water emulsions. The effects of TEOS/NH₃·H₂O addition and CS–50 concentration on the microstructure and wettability of the obtained samples as well as the oil/water separation continuous performance and extreme environmental stability were investigated. The results show that the maximum oil contact angles in air and water of the prepared SSMDPC are 153° and 158° respectively at TEOS/NH₃·H₂O addition of 5%/2% and CS–50 addition of 5% respectively. The continuous separation flux and separation efficiency of SSMDPC for edible oil/water mixture and edible oil-in-water emulsion with a surfactant (5/95, mass ratio) are 162.3 kg·min^-1·m^-2 and 98.3%, 93.7 kg·min^-1·m^-2 and 91.3%, respectively. Moreover，SMDPC can still maintain stable hydrophilic and hydrophobic properties under corrosion conditions (i.e., pH value of 1, pH value of 14 and 1 M NaCl), even at –196℃ and 200℃, which has broad application prospects in oil-in-water emulsion.