Ceramic membranes for water separation from organic solvents

Novel hydrophilic SiOx modified alumina membranes with high separation factors and flux rates have been prepared for the separation of water from organic solvents. For the preparation of the membranes, SiOx networks are deposited inside the γ-Al2O3 layer of a commercial ultrafiltration membrane by hydrolysis of tetraethylorthosilicate in autoclaves at 250 °C. The transport resistances of the individual membrane layers for the permeation flux are described by a model. The membranes are stable towards solvents to temperatures of at least 150°C. Pervaporation studies show that water can be separated from solvents such as acetonitrile, tetrahydrofurane, 2-propanol, ethyl alcohol, dimethylsulfoxide, N,N-dimethylformamide, and phenol. The separation performance of the membranes allows their use in technical separation processes, especially for the removal of water.