Physical Chemistry Studies of Acid Dye Removal from Aqueous Media by Mesoporous Nano Composite: Adsorption Isotherm, Kinetic and Thermodynamic Studies

Abstract

In this research, SBA-15/Polypyrrole (SBA-15/PPy) mesoporous nanocomposite was synthesized, characterized and applied for Acid Blue 62 (AB62) adsorption as a textile dye from aqueous solution. In order to evaluate the structural properties of synthesized adsorbent, FT-IR, FESEM and TEM images, XRD, and BET techniques were applied. Some parameters such as pH, dosage, and time which affect the batch adsorption process were investigated and optimized as well. The optimized condition was achieved by 0.3 g/l adsorbent at pH = 2 and 60 min in contact. In addition, Langmuir, Freundlich, Temkin, Dubinin–Radushkevich (D-R) and Redlich–Peterson (R-P) adsorption isotherms were employed to determine type of adsorption isotherm. The results showed the agreement of experimental data with Langmuir adsorption isotherm with maximum dye 1428.571 mg/g adsorption capacity. The kinetic analysis was carried out by pseudo-first-order, pseudo-second-order, intra-particle diffusion and Elovich models. The results revealed that the adsorption kinetic is more similar to the pseudo -second-order. The parameters of thermodynamic like ΔH°, ΔG°, and ΔS° were calculated. The ΔG° and ΔH° negative values and ΔS° positive values (5.155 J/mol K) illustrated that AB62 adsorption process is physi-sorption, spontaneous, exothermic and feasible.