Hydrophobic Silica Thin Film derived from Dimethyldimethoxysilane-Tetraethylorthosilicate for Desalination

Silica thin film preparation was carried out from dimethyldimethoxysilane (DMDMS) and tetraethylorthosilicate (TEOS) precursors using the sol-gel method, and the effect of pH on the character of the resulting silica mem-brane was also studied. The solution pH was varied into 2.21; 3.92; 4.98; 6.44; and 7.21. The resulting xerogel was analyzed using Fourier-transform infrared spectroscopy, Thermogravimetric Analysis, and Gas Sorption Analysis. While the silica thin layer was measured for its hydrophobic character and surface morphology using Scanning Electron Microscope. The presence of DMDMS-TEOS silica thin film had a considerable influence on the hydrophobic nature of the ceramic plate surface. The membrane prepared under neutral conditions produced desirable properties, such as higher thermal stability, greater pore volume, thermal stability, and higher hy-drophobicity. For the desalination process, the obtained silica membrane showed excellent separation perfor-mance (>99%), especially at low salt concentrations. When the pH increased, the water flux also increased. The thin films worked well for desalination through a pervaporation mechanism.