Separation and Purification Technology, Vol.75, No.3, 286-294, 2010
Modification of silicalite-1 by vinyltrimethoxysilane (VTMS) and preparation of silicalite-1 filled polydimethylsiloxane (PDMS) hybrid pervaporation membranes
In preparation of inorganic particles filled polymer membranes, coupling agents can help to improve the compatibility between inorganic filler and polymer matrix. In this paper, surface modification of silicalite-1 was performed by a coupling agent, vinyltrimethoxysilane (VTMS), and hybrid pervaporation membranes were prepared by incorporating the unmodified or VTMS-modified silicalite-1 into polydimethylsiloxane (PDMS). The VTMS-modified silicalite-1 particles and hybrid membranes were characterized by FT-IR, Si-29 CP MAS NMR, DSC, TGA, XRD and SEM. The results showed that the coupling agent VTMS was readily grafted on the surface of silicalite-1 by hydrolysis reaction and condensation reaction, and the chemical linking between the -CH=CH2 group on the surface-modified silicalite-1 and -Si-H on the PDMS substantially eliminated the nonselective voids inside the membrane. When used to separate acetone, butanol, ethanol (ABE) from aqueous solution, a higher selectivity was obtained with the VTMS-modified silicalite-1/PDMS hybrid membrane. Moreover, the surface modification of silicalite-1 improved its dispersion in PDMS and increased the maximal loading of silicalite-1 in membrane preparation, and thus further enhanced the separation factor of the membrane. (C) 2010 Elsevier B.V. All rights reserved.
Keywords:Pervaporation;Silicalite;Polydimethylsiloxane (PDMS);Vinyltrimethoxysilane (VTMS);Hybrid membrane