Optimization of preparation process and characterization for hydrophobic α-Al2O3 ceramic membrane

Hydrophobic α-Al2O3 ceramic membrane (HCM) offers excellent mechanical properties, corrosion resistance, and high-temperature resistance. Application of HCM in the membrane distillation (MD) process could expand the application scope of MD equipment and greatly lengthen the replacement cycle of the membrane. Here a prediction model of the contact angle of HCM was constructed by physical-chemical combined modification method, orthogonal method, and stepwise linear regression method to optimize the preparation process of HCM. The surface morphology, contact angle, and surface functional groups of HCM were characterized. In this work, we polished the surface of the α-Al2O3 ceramic membrane with 400 mesh sandpaper to copy the optimal morphology and found that the effect of grafting time on the contact angle of HCM could be abandoned. The optimal levels of drying temperature, drying time, and grafting solution concentration were 250 °C, 65.5 min, and 0.019 mol/L, respectively. The contact angle of HCM was 145.3° corresponding to the optimal preparation process. The significance of the prediction model of the contact angle of HCM was better than 0.05, and all of the prediction errors were less than 5%. This work has an important guiding value for exploiting the optimum hydrophobic property of HCM.