Research papers VOC adsorption on raw and modified clay materials Ikram Jarraya a, ⁎, Sophie Fourmentin b,c , Mourad Benzina a , Samir Bouaziz a a Laboratoire de Recherche LR 3E - Ecole Nationale d'Ingénieurs de Sfax, B. P. “W” 3038 Sfax, Tunisia b Univ Lille Nord de France, F-59000 Lille, France c ULCO, LSOE, F-59140 Dunkerque, France abstract article info Article history: Received 18 June 2009 Received in revised form 13 April 2010 Accepted 20 April 2010 Editor: D.B. Dingwell Keywords: Organoclay Adsorption Volatile organic compounds Adsorption isotherm The porous texture of clays gives them a capital interest for a possible use in the elimination of environment contamination by the adsorption of several pollutants. The material used in the present study is taken from the Douiret formation in Tataouine in the south of Tunisia. Besides, the modification of the clay material was made by intercalation of the didodecyldimethyl ammonium bromide. Such intercalation allows the enhancement of the porous texture of the material in question, which supports its uses in the adsorption of volatile organic compounds (VOCs). Furthermore, the adsorption isotherms showed that the intercalation of the didodecyldimethyl ammonium bromide on clay material improved its adsorption capacity for toluene, cyclohexane and chlorobenzene to reach 2, 2.5 and 3.5 mg g -1 respectively. © 2010 Elsevier B.V. All rights reserved. 1. Introduction The emissions of volatile organic compounds (VOCs) are becoming one of the most stringent environmental challenges in many industrial processes. In fact, VOCs are known to be among the major contributors to the formation of photochemical ozone and secondary organic aerosol (SOA), which would result in health damage and serious environmental problems. The abatement techniques of VOCs can be divided into two categories. The first one is the destructive techniques such as thermal oxidation and catalytic oxidation, which eliminate the undesirable compounds, and the second is the recuperative techniques such as adsorption, absorption, and condensation. In general, condensation is more effective than adsorption when VOC concentrations are relatively at higher levels (N 1%) (Khan and Ghoshal, 2000). Therefore, adsorption which is a reliable chemical engi- neering method is widely used thanks to the flexibility of the system, low energy and cheap operation costs (Serrano et al., 2004). This technique has been found to be effective at low concentration levels (ppm or sub- ppm) (Gupta and Verma, 2002). Up to now, only 10% of the industrial abatement units are based on adsorption. This percentage should, nevertheless, increase in the near future given the strict control over VOCs releases set by the regulations. This explains the current growing interest in the development of highly efficient industrial adsorbents for the treatment of VOC-loaded waste gases (Zaitan et al., 2008). Activated carbon is also the most widespread alternative to elimi- nate the volatile organic compounds due to its developed microporosity which ensures good adsorption capacities (Manjare and Ghoshal, 2006). However, its application is limited by the sensitivity to high temperature and the difficulty of regeneration because of its thermal and chemical instability, causing significant safety problems. On the other hand, hydrophobic zeolites are on average ten times more expensive and they are sensitive to the presence of humidity (Zaitan et al., 2008). Hence, different alternative adsorbents are desirable to be developed to overcome these kinds of problems (Hu et al., 2009). In addition to their use in various fields of the human life like agriculture and industry (pharmaceutical, cosmetic, ceramic, painting, rubber, plastic, etc.), the natural clays are very abundant materials with a low cost and porous texture. Such characteristics make them of a capital interest for a possible use in the adsorption of VOCs for their removal from waste gases. The material exploited in the present study is taken from the Douiret formation of Tataouine in the south of Tunisia. The layer of such area has a lower Aptian age and belongs to the Merbah el Asfer group. The objective of this work is to improve the adsorbent properties of the clay material by intercalation of organic molecules; the didodecyl- dimethyl ammonium bromide, in the porous texture. Indeed, cyclohex- ane, toluene and chlorobenzene were selected for the study of VOC adsorption since they are known to be among the most harmful VOCs. 2. Experimental 2.1. Materials The clay material used in this study is taken from deposits located in the south of Tunisia from the area of Douiret; which belongs to the Chemical Geology 275 (2010) 1–8 ⁎ Corresponding author. Tel.: +216 74 274 088; fax: +216 74 275 595. E-mail address: jarrayaikram@yahoo.fr (I. Jarraya). 0009-2541/$ – see front matter © 2010 Elsevier B.V. All rights reserved. doi:10.1016/j.chemgeo.2010.04.004 Contents lists available at ScienceDirect Chemical Geology journal homepage: www.elsevier.com/locate/chemgeo