Pervaporation membrane for desalination derived from tetraethylorthosilicate-methyltriethoxysilane

• Published in: Journal of sol-gel science and technology Vol. 101; no. 3; pp. 505 - 518
• Main Authors: Darmawan, Adi, Munzakka, Labib, Karlina, Linda, Saputra, Riza Eka, Sriatun, S., Astuti, Yayuk, Wahyuni, Ayu Sri
• Format: Journal Article
• Language: English
• Published: New York Springer US 01.03.2022; Springer Nature B.V
• Subjects: Acetic acid; Ceramics; Chemistry and Materials Science; Composites; Composition; Contact angle; Desalination; Ethanol; Glass; Hydrophobicity; Inorganic Chemistry; Materials Science; Membranes; Nanotechnology; Natural Materials; Optical and Electronic Materials; Original Paper: Functional coatings; Pervaporation; Rejection; Saline water; Silicon dioxide; Sol-gel processes; Tetraethyl orthosilicate; Thermal stability; Thin films; thin films and membranes (including deposition techniques); Xerogels; Silica membrane; Tetraethylorthosilicate (TEOS); Methyltriethoxysilane (MTES); Desalination; Pervaporation
• ISSN: 0928-0707; 1573-4846
• DOI: 10.1007/s10971-022-05754-8

Silica membrane synthesis from tetraethoxysilane (TEOS) and methyltriethoxysilane (MTES) was carried out using ethanol-acetic acid solvent through a sol–gel process. The effects of TEOS-MTES mol composition of 100-0, 90-10, 75-25, 50-50, 25-75, 10-90, and 0-100 and calcination temperatures of 350 and 500 °C were studied. The water contact angle was used to examine the hydrophobicity of silica thin films. A close correlation between hydrophobicity and the presence of the Si−OH and C–H groups was obtained. Hydrophobicity was enhanced by increasing the C−H/Si−O−Si ratio and decreasing Si−OH/Si−O−Si ratio. Silica membrane material maintained hydrophobic properties up to 400 °C. Thermal stability went up with the rise in MTES content. All silica xerogels exhibited microporous character with decreased pore volume and surface area with lower TEOS content. The pervaporation technique systematically studied the TEOS-MTES silica membrane’s desalination performance using various saltwater concentrations and feed temperatures. The TEOS-MTES composition played an essential role in determining the membrane’s character and performance, salt rejection, and water fluxes. The high TEOS content led to high water flux. Alternatively, a high MTES content led to a high salt rejection. All membranes provided good salt rejection with values up to 99%, especially those with high MTES contents. Graphical abstract Highlights Silica membranes are synthesized using tetraethylorthosilicate-methyltriethoxysilane. There is a strong correlation between hydrophobicity with Si−OH and C−H groups. The silica membrane material maintained hydrophobic properties up to 400 °C. Precursor composition influences the performance of pervaporation desalination. Silica membranes produce high-salt rejection and good water flux.