Vacuum versus air calcination of modified TEOS-MTES based membrane for seawater desalination.

Tetraethyl orthosilicate-methytriethoxysilane (TEOS-MTES) was successfully fabricated in this work to be applied in desalination. The aim of this work is to investigate xerogel deconvolution and membrane performance of TEOS-MTES under air and vacuum calcination for processing seawater salt solution (3.5% NaCl) via pervaporation. TEOS as silica precursor, nitric acid, and ammonia as dual acid-based catalysts were mixed by sol-gel process. The xerogels were calcined at 350 0C for 1 h under air and vacuum conditions, subsequently, xerogels were characterized via Fourier-Transform infrared spectrometer (FTIR). Fityk software was used to deconvolute the peak area in the FTIR. Whereas the membrane is dip-coated up to 4 times to be obtained 4 layers. The performance is tested through pervaporation at 25 °C feed temperature. Results show all MTES xerogels have carbon groups, silanol, and siloxane peaks. The organo-silica membrane water flux calcined under vacuum condition has almost 2-fold times higher than air calcination. Furthermore, all the TEOS-MTES showed about 99% of salt rejection. The membrane prepared under vacuum calcination has better performance than air calcination. [ABSTRACT FROM AUTHOR]