Basic RED-5 adsorption on montmorillonite: faktorial design, equilibrium, kinetic and thermodynamic studies

In this study, the adsorption performance of montmorillonite (MMT) was evaluated by Basic Red- 5 adsorption experiments considering the influencing factors (initial BR-5 concentration, dosage, time, pH, and temperature). The surface and structural properties were characterized by FT-IR, XRD, XRF, SEM-EDS, AFM, and BET techniques. The adsorption experiments were carried out by batch mode for the evaluation of isotherm, kinetic, and thermodynamic studies. The results of equilibrium adsorption isotherm were interpreted using different isotherm models. The equilibrium data fitted well with the Langmuir isotherm models, and the maximum adsorption capacity was found as 163.93 mg/g. Adsorption data of the BR-5 onto MMT provide well by pseudo-second-order model (R 2 = 0.999). The Δ H o , Δ S o and Δ G o values were calculated for the nature of the adsorption process. The analysis of the thermodynamic parameters showed spontaneous, exothermic, and viable adsorption of BR-5 under the investigated experimental conditions. A factorial design was applied to examine the effect of three factors initial concentration of dye (50 and 100 mg/L), time (60 and 120 min.) and dosage (0.05 and 1.00 mg/L) on the adsorption process. According to the results, with high efficient adsorption capacity and compatible surface properties are advantageous to be used for uptake of dyes.