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A B S T R A C TThe present work is concerned with a comparative study to evaluate the adsorptive properties of activated carbons produced from coffee grounds. Activation was done using different chemical activation agents such as H 3 PO 4 and ZnCl 2 either separately or mixed together. Characterization of these prepared samples was carried out by determining their physicochemical properties such as specific surface area, porosity, and surface acidity. The results indicated that the produced carbonaceous materials generally developed different and interesting porous structures. Indeed, H 3 PO 4 -activated carbon (PPAC-P) develops a porous volume of 0.98 cm 3 /g and a surface acidity of 317.6 meq/100 g (with a high mesoporous proportion). By contrast, ZnCl 2 -activated carbon (PPAC-Z) seems to be the most microporous material with a rather limited surface acidity. Adsorption trials with Malathion, a commercial pesticide widely used in Algeria, were carried out onto produced samples of carbonaceous materials in batch experiments at 30˚C. Various parameters such as pH, contact time, nature, and amount of adsorbent were investigated for removal efficiency under different operational conditions. Results herein showed that an interesting removal efficiency of 96% was achieved under the following conditions: pH 6, adsorbent amount of 1 g/L, and an equilibrium time of 60 min.

Elaboration of new structures based on semi-conductors and conducting polymers can procure a new alternative to the development of various electrochemical sensors with good sensibility.The key idea of this paper is to develop a facile technique for the detection of the para-nitrophenol which is considered as an important toxic pollutant. In this context, different structures based on mesoporous silicon modi ed with Polypyrrole (PPy) were elaborated.The hybrid structures have been characterized by several techniques such as FTIR, SEM and Contact angle measurements.In addition, the behavior of these new structures for para-nitrophenol detection by cyclic voltammetry was studied. The results show a high sensitivity of the sensor in a large concentration interval.

In this work, the polystyrene (PS) coating onto the porous silicon by three different methods (dip coating, spin coating and spreading) has been studied. For this purpose, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) have been carried out to evaluate the surface modification. The FTIR spectra showed the presence of strong hydrogen binding which occurred between the hydroxyl groups present at the surface of the porous silicon substrate and the π electrons of the polystyrene aromatic ring. Moreover, the EDS spectrum showed the presence of a peak attributed to the carbon which is the principal constituent of the PS polymer. Also, SEM observations showed that the morphology of the PS macromolecular chains depends strongly on the deposition‐ coating method. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)