Preparation method of Janus ceramic membrane and application of Janus ceramic membrane in dispersion-intensified bubble aeration process

A method of producing a Janus ceramic membrane for use in a dispersion-intensified bubble aeration process, wherein the Janus ceramic membrane has an asymmetric wettability structure;

• the Janus ceramic membrane is produced by grafting a hydrophobic group on a substrate membrane in situ through impregnation of a perfluoroalkylsilane (FAS), and forming a hydrophilic coating through unilateral asymmetric surface deposition of dopamine (DA);
• comprising the following steps:
• step 1, cleaning and oven-drying a sheet ceramic substrate membrane;
• step 2, adding the FAS to cyclohexane, and thoroughly mixing to prepare a first solution;
• step 3, impregnating an oven-dried substrate membrane in the first solution, cleaning, and oven-drying to produce a hydrophobic ceramic membrane;
• step 4, dissolving the DA in deionized water, and adding a Tris-HCl buffer to prepare a second solution;
• and
• step 5, placing a single side of the hydrophobic ceramic membrane in the second solution for deposition or coating the second solution evenly on the single side of the hydrophobic ceramic membrane, and cleaning and drying to produce the Janus ceramic membrane, wherein:
• in the step 5, the deposition is conducted for 0.5 h to 10 h,
• the cleaning comprises rinsing with deionized water for 5 min to 15 min,
• the drying is conducted at 60° C. to 80° C. for 8 h to 16 h, and
• the FAS is one of:
• perfluoro-n-hexyltrimethoxysilane, perfluoro-n-octyltrimethoxysilane, and perfluorododecyltrimethoxysilane, and wherein the Janus ceramic membrane produced exhibits, when used in a membrane-dispersed air-water system with the hydrophilic surface contacting the liquid phase and the hydrophobic surface contacting the gas phase:
• (i) a gas inlet pressure to initiate bubbling of about 0.02 MPa and at least ten times lower than that of a hydrophilic Al2O3 substrate membrane, and (ii) an average bubble diameter of about 150 μm to about 180 μm.