Hydrophobic modification of alumina-based tubular ceramic surface and its characterisation

An alumina-based ceramic tubular support surface has been modified with commercially available organosilanes to impart hydrophobic characteristics for its possible application in membrane distillation applications. These membranes were fired at higher temperatures; hence, limited hydroxyl groups were present on the ceramic support surface for coupling with organosilanes. A suitable layer of silica sol was coated to increase the availability of hydroxyl groups before hydrophobic agents. It was observed that providing the intermediate layer enhanced the gripping of silanes with support as well as durability of the hydrophobic membrane increased. The water contact of the hydrophobic surface was 143° and remains unaltered even at 80 °C for 96 h. EDX spectrum showed the presence of silanes on the surface and the XPS depth profile showed a coating of 100 nm. The liquid entry pressure of the membrane was observed as 2.1–2.2 kg/cm2 which is comparable with the commercially available polymeric hydrophobic membranes. The developed hydrophobic membranes may be used for desalination applications.