Abstract
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 d001 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 m2/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 and nonlinear Langmuir model. The CBB dye kinetic adsorption is better fitted by the pseudo-second-order model. Thermodynamic study indicated the feasibility and spontaneity of the CCB dye adsorption process that was exothermic and physical in nature. A comprehensive adsorption and mechanism interaction study of CBB molecular structure onto PILC-Fe was appropriately discussed.