Synthesize and characterization of Aminosilane functionalized MCM-41 for removal of anionic dye: Kinetic and thermodynamic study

In this study, removal of Acid blue 62 from aqueous solution by mesoporous silicate MCM-41 modified by Aminopropyltriethoxysilane (APTES) composite was studied. Properties of synthesized composite were analyzed and confirmed by SEM, EDX and FTIR. Results show that Langmuir adsorption isotherm has the best compatibility with the results of experiments. Kinetic analysis using pseudo-first-order model, pseudo-second-order and the intra-particle diffusion model was carried out. Results also confirmed that adsorption process is compatible with the pseudo-second-order kinetic model. Thermodynamic parameters such as Gibbs free energy changes (ΔGo), Enthalpy changes (ΔHo) and Entropy changes (ΔSo) were calculated. Negative value of ΔGo and positive value of ΔHo show that adsorption of Acid blue 62 on aminated nanocomposite is a spontaneous process also endothermic.