Polydimethylsiloxane /Ceramic Nanocomposite Hybrid Membrane for Condensable Hydrocarbons Separation

Membrane operations are innovative gas separation technologies used successfully in industrial scale [1].Operating simplicity, intrinsic modularity and absence of additives to perform the separation are some of their strong points with respect to the conventional separation methods. Recently, membrane-basedprocesses have also been proposed for the recovery of higher hydrocarbons (C2+) from natural gas or hydrogen-containing off-gas streams [2]. Properties of inorganic substrates like high flux and high mechanical, chemical and thermal stability make them ideal supports for gas separation applications. But, the controlling gas transport mechanism in the porous ceramic membranes with nanometric pore size (<10 nm) is Knudsen flow, which provides a low selectivity. Such shortcomings can be overcome by surface modification of the ceramic substrate with a polymeric active layer [3]. Among the rubbery polymers, polydimethylsiloxane (PDMS) is a solubility-selective polymer that is more permeable to vapors (condensable gases) than to non-condensable gases [4]. Therefore, study on the ceramic-polymer hybrid membranes design that combines best properties of both polymeric and ceramic membranes is necessary. In this work, a new fabrication method giving PDMS/ceramic nanocomposite membrane is described. To demonstrate the potential of the composite membrane in higher hydrocarbons separation, we focused on the separation of butane from hydrogen and compared results with those of dense homogeneous PDMS membrane.