Adsorption equilibrium studies for O‐xylene vapour and modified clays system

Tunisian bentonites were used to prepare three modified clays: two organoclays by intercalating respectively didodecyldimethylammoniumbromide (DDMAC) and hexadecyltrimethylammoniumbromide (HDTMAC), and synthesis of NaX zeolite. The X-ray diffraction, infrared and thermogravimetric analyses enabled us to differentiate between the structures obtained. Clay materials systems were used as adsorbent for the investigation of the adsorption isotherms and saturation capacity of O-xylene, a toxic volatile organic compound, by gravimetric method at three different temperatures 20, 30, and 40 degrees C. The absolute values of the volatile organic compound adsorbed amounts in the intercalated clays (604mgg-1) were higher than for the zeolite (296mgg-1). The adsorption isotherms were analysed by the Freundlich and Langmuir equations. The latter was found to describe better the equilibrium adsorption data. Mass transfer coefficient of O-xylene is evaluated using uptake curve method, and all values are in the order of 10-2s-1. Copyright (c) 2014 John Wiley & Sons, Ltd.