Self-cleaning SiC membranes modified with TA-PEI for high-temperature oil–water separation

The treatment of oil-containing wastewater poses significant environmental challenges due to its complex composition and high emulsification. Membrane technology offers an energy-efficient alternative for oil–water separation. This study explores the surface physicochemical properties, self-cleaning capabilities, and high-temperature oil–water separation applications of silicon carbide (SiC) ceramic membranes modified with a tannic acid/polyethyleneimine (TA/PEI) complexes. The TA/PEI@SiC membrane, prepared via a complex solution, exhibits increased water contact angle but still maintains hydrophilicity and underwater superoleophobicity. The TA/PEI@SiC membrane demonstrated exceptional high-temperature stability, maintaining separation efficiency above 97.73 % across a range of temperatures (60–90 °C). In cyclic tests, the membrane maintained emulsion separation efficiencies of 99.53–99.95 % at 60 °C, 98.59–99.53 % at 70 °C, 98.75–99.68 % at 80 °C, and 97.53–99.39 % at 90 °C. Research has shown that oil droplets can spontaneously detach from the membrane surface underwater, demonstrating effective self-cleaning properties.