Separation of Aromatic and Alcoholic Mixtures using Novel MWCNT-Silica Gel Nanocomposite as an Adsorbent in Gas Chromatography Seyed Mojtaba Mostafavi* 1 , Ahmad Rouhollahi 1 , Ali Mohajeri 2 and Masoumeh Piryaei 3 1-Department of Chemistry, K.N. Toosi University of Technology, Tehran-Iran 2- Research Institute of Petroleum Industry, Tehran-Iran 3- Department of Biology, Faculty of Science, Payam Nour University, Tehran, Iran Abstract The separations of alcohols with hydrophilic and hydrophobic parts, and the separation of aromatic mixtures, are extremely important processes in gas and petroleum industries. Choosing an adsorbent for performing this separation is the most important part of the process. Silica gel is used as an adsorbent is various techniques such as pressure swing adsorption (PSA) and gas and liquid chromatography. Due to the polarity of silica gel, it is used for the separation of polar molecules. Carbon materials such as activated carbon and recently carbon nanotube (CNTs) are widely used for the separation of nonpolar materials. In the course of this study, a new composite was fabricated using sol-gel methods. Multiwall carbon nanotubes (non-polar carbon-based adsorbents with high surface areas) were mixed with a silica gel base (a strong polar adsorbent). The composite was then used in the separation of mixtures of both aromatic hydrocarbons and alcohols. Keywords: MWCNTs-SiO2, Nanocomposite, Sol-Gel process, Gas Chromatography, Aromatic Hydrocarbons, Primary Alcohols © 2014 Published by Journal of Nanoanalysis. 1. Introduction Molecular sieves, porous polymers (e.g. Porapak), activated carbons and silica are different sorbents that have long been used in gas chromatography and other gas separation techniques. Almost all of these sorbents have an upper temperature limit about 250-350 °C. Different methods for the fabrication and modification of packed columns and capillary columns are employed according to column type (1). The characteristics and capabilities of silica gel make this material one of the most important bases for the separation of polar mixtures. It is considered as a good sorbent for packed column GC. The Sol-gel method is effective for the fabrication of silica gel and the formation of silica composite (2), (3). One petrochemical application of silica gel is the adsorption of H2S, N2O4 and some other gases (4). Silica gel has good properties for the separation of certain materials. However, this sorbent does not provide enough surface area for performing separations. Also, The surface specification of silica gel is * Corresponding author email address: smmostaf@deakin.edu,.au , Tel: +61470600607