Fabrication of silicalite-1/PDMDES nanocomposite membranes with improved compatibility for enhanced alcohols recovery by pervaporation

Herein, we present a newly developed nanocomposite membrane composed of a poly-dimethyldiethoxysilane (PDMDES) matrix incorporated with silicalite-1 nanoparticles, aimed at achieving enhanced alcohol recovery. Two strategies, pre-heating and surface modification, were utilized to facilitate the creation of chemical bonds, hence improving the compatibility between fillers and the polymer. Vinyltriethoxysilane (VTES), a cross-linking agent in the preparation of PDMDES membrane, was also utilized as a silane coupling agent for the surface modification of silicalite-1. Comprehensive characterizations were conducted on both the original and VTES-modified silicalite-1 nanoparticles, along with the nanocomposite membranes. Encouraging results reveal that surface modification proved to be a more effective approach in facilitating the creation of chemical bonds, thus improving compatibility between modified silicalite-1 and PDMDES polymer. The pervaporation performance of these prepared nanocomposite membranes was thoroughly investigated. Comparison results demonstrate that the nanocomposite membrane after surface modification exhibited enhanced flux and separation factor, as compared to both the nanocomposite membrane after pre-heating and the pristine PDMDES membrane. Accordingly, an enhanced pervaporation performance with a total flux of 6.07 kg∙m-2h-1 and a competitive separation factor of 9.46 was obtained by incorporating surface modified silicalite-1 nanoparticles into the PDMDES membrane at a filler loading of 15 wt% in separating 5 wt% ethanol/water mixture at 40 °C.