Sorptive Removal of Methyl Green from Aqueous Solutions using Activated Bentonite

Bentonite clay from Maghnia (North West Algeria) has been acid-activated. The activated bentonite was employed as adsorbent for the removal of methyl green from aqueous solutions using adsorption method. The influence of several parameters (kinetics, contact time, sorbent amount, adsorbate concentration and pH) on the adsorption capacity was evaluated and discussed. The Langmuir adsorption model was applied to experimental equilibrium data and the isotherm constant was calculated. The results indicated that the adsorption was favourable at neutral pH. This model provided the best fit to the experimental data with high correlation coefficient (R²=0.996). The monolayer adsorption capacity of activated bentonite found to be 353.33 mg/g. It was seen that pseudo-first order equation describes the adsorption kinetics. The results indicated that this bentonite-type clay is potential to be used as an economical adsorbent for the removal of methyl green dye

The Role of CeO₂-Doping of γ-Al₂O₃ on its Structural and Superficial Area

A series of samples, noted Al_xCe_{1-x} has been prepared by hydrolysis, from γ-Al₂O₃ and CeO₂. These samples were calcined under air at 450, 900 and 1200°C, and then characterized by specific surface area, X-ray diffraction and thermoreduction programmed under H₂. Obtained results show that after calcination at 450 and 900°C, the cerium decreases the surface of alumina. Results of X-ray diffraction and thermoreduction programmed under H₂ experiments showed that the samples are constituted of: γ-Al₂O₃ and CeO₂. The global consumption of hydrogen increase with rate of CeO₂ added. At 1200°C, the sintering of the samples is very important and γ-Al₂O₃ is transformed into the α-phase. The decrease in specific surface area is more accentuated for Al₁Ce₀ sample, since sintering occurs due to the growth in crystallite size. Thermoreduction programmed under H₂ experiments show that reduction of CeO₂ much more accentuated for ceria samples or its decrease can reflect some alterations of the nature of interactions between Al₂O₃ and CeO₂

Platypalpus verbekei Grootaert & Chvala, 1992, nova espècie per Algèria i pel Nord d'Àfrica amb un catàleg de les espècies conegudes d'Algèria de la família Hybotidae (Diptera: Empidoidea: Hybotidae)

Based on the collections made in crop fields in Mostaganem (Algeria), an updated list of the Hybotidae species of Algeria is performed. The species Platypalpus verbekei Grootaert & Chvala, 1992 is here cited for the first time in North Africa. This species has a chromatic variation and a certain clypeus variation respect the European populations which are here detailed. In order to facilitate the recognition of this species it is included in this study a diagnosis (in Catalan) and a redescription (in English) based on the specimens collected from the Algerian population, showing the phenotypic variability of the species present in the two shores of the Mediterranean. In total 27 species distributed in 5 genera are known so far in Algeria, of which 4 are cited only in Algeria. Two species are excluded from the catalogue of the Algerian species giving the reasons for that decisio

Platypalpus verbekei Grootaert & Chvala, 1992, nova espècie per Algèria i pel Nord d'Àfrica amb un catàleg de les espècies conegudes d'Algèria de la família Hybotidae (Diptera: Empidoidea: Hybotidae)

Based on the collections made in crop fields in Mostaganem (Algeria), an updated list of the Hybotidae species of Algeria is performed. The species Platypalpus verbekei Grootaert & Chvala, 1992 is here cited for the first time in North Africa. This species has a chromatic variation and a certain clypeus variation respect the European populations which are here detailed. In order to facilitate the recognition of this species it is included in this study a diagnosis (in Catalan) and a redescription (in English) based on the specimens collected from the Algerian population, showing the phenotypic variability of the species present in the two shores of the Mediterranean. In total 27 species distributed in 5 genera are known so far in Algeria, of which 4 are cited only in Algeria. Two species are excluded from the catalogue of the Algerian species giving the reasons for that decisio