Fabrication of organo-silica thin film for water desalination from dual silicate precursor (tetraethylorthosilicate & methyltriethoxysilane)

A modification of silica structure is urgently needed to improve silica-based matrices applied for water desalination. It is due to the hydrophilic properties owned by pure silica structures, and it is also caused by the silica pore was collapse during ions water exposed on membrane surfaces. According to that, this study is aimed to fabricate and to observe the innovation of silica membranes modified matrices by mixing the main precursor of tetraethylorthosilicate (TEOS) and methyltriethoxysilane (MTES) as sources of silicate as well as carbon applied for water desalination. The mixtures of MTES:TEOS (10:90) was mixed with acid-base catalysts using sol gel method. This process and reaction were held for 3 h nonstop. The modified organo-silica sols were dried by oven for 24 h and grinded into powder that called xerogel. Then it was calcined using furnace for 1 h at 350 and 450 °C using RTP (rapid thermal processing) method which under variation of condition (vacuum and air/atmosphere). Functionalization of modified organo-silica membranes were investigated using FTIR spectra and Fityk software. The results show the modified organo-silica derived from MTES (as a carbon source) exhibited the functionalization of siloxane (Si-O-Si), silanol (Si-OH), and silica-carbon (Si-C) functional groups. The optimum organo-silica MTES:TEOS mixture was obtained from sample calcined at 450 °C under vacuum calcination. The presence of carbon bonds causes the pores formed tend to be small but strong so it is suitable for application in the desalination process.