The isotherms and kinetics of the adsorption of a cationic dye in aqueous solution, methylene blue, on a local Algerian montmorillonite clay mineral (raw, sodium and thermally activated at 300 and 500˚C) were determined experimentally. Various parameters influencing the adsorption were optimized, mainly solid-liquid contact time, mass of adsorbent, initial concentration of dye, pH of the solution and temperature. Results showed that the adsorption kinetics were fast: 30 min for the raw clay mineral, and 20 min for sodium clay mineral (SC) and thermally activated at 300˚C, whereas with the clay mineral calcined at 500˚C, the equilibrium was reached after 150 min only. The maximum adsorption capacity was reached at pH 6.6. Results deducted from the adsorption isotherms also showed that the retention follows the Langmuir model. In addition, it was found that the kinetics were in the order of 2 (K = 2.457 × 10 6 g/mg.h) for sodium clay and were limited by an intra-particle diffusion. SC was found to be a better adsorbent to remove methylene blue from industrial wastewater.

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This study aims to prepare the sodium bentonite (Bent-Na) and the iron-pillared bentonite (PILC-Fe) and to evaluate its adsorption efficacy against Coomassie blue from aqueous solution. Results demonstrated that the PILC-Fe sample presents an increase in the basal distance d 001 from 13.66 to 16.93 Å. The presence of the Fe-O and FeOOH functional group band on PILC-Fe was confirmed by FTIR analysis. A clear increase has been observed of the specific surface area from 45.86 to 125.30 m 2 /g for Bent-Raw and PILC-Fe, respectively, and this increase is greater than 63%. Adsorption of CBB dye into Bent-Na and PILC-Fe was fast, and their adsorption equilibriums were reached within 15 and 5 min, respectively. The maximum adsorption capacity for CBB dye is 9.125 mg/g for PILC-Fe, whereas Bent-Na presents a lower adsorption capacity of around 6.848 mg/g. The maximum CBB dye adsorption rate was attained at pH 4.68 for both bentonites. It is observed a difference in the removal efficiency implying that the adsorption of CBB molecule dye was affected by the structure and functional groups of dyes. It is noticed that the adsorption process for CBB dye into Bent-Na and PILC-Fe was better fitted with the linear * A. Ramdani

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