Sol-Gel Approaches in the Synthesis of Membrane Materials for Nanofiltration and Pervaporation

Abstract

Molecular separation using membranes is widely considered as anenergy-efficient alternative for conventional industrial separationtechniques. For the preparation of such membranes sol-gel technology ishighly Suitable. Using sol-gel techniques thin (50-100 nm) amorphousnanoporous layers having pore sizes in the micropore (<2 nm) or finemesoporous (<5 nm) region call be prepared oil a porous Substrate. Theselayered porous systems, usually ill tubular form, call be used fornanofiltration, pervaporation and gas separation applications. Theapplication window is dependent oil the material properties, Such as thepore size and pore size distribution, the interfacial properties of thepores, and the defect density. The Success of this technology in actualindustrial applications strongly depends oil reproducible large scaleproduction of the solgel membranes and oil a Sufficient stability of themembranes with respect to flux and selectivity. In addition theproduction cost of the full membranes system is an important aspect.Here, we will focus on the more chemical aspects in the membranepreparation. Main topics are synthesis and properties of the sols, thepreparation of microporous thin films, and the search for membranematerials that have a high hydrothermal stability.