Kinetic, equilibrium and thermodynamic studies for rhodamine B adsorption on sodium tauroglycocholate functionalized mesoporous silica nanoparticles

The purpose of research objectives is to to synthesize sodium tauroglycocholate functionalized mesoporous silica nanoparticles (MSNPs–STGC) and study its suitability as adsorbents to remove Rhodamine B (RhB) from contaminated water. The fabricated nanoparticles were characterized by fourier-transform infrared spectroscopy (FTIR), elemental analysis, dynamic light scattering (DLS), scanning electron microscope (SEM) and transmission electron microscopy (TEM). The characterization results demonstrated that MSNPs had been successfully fabricated with average diameters of 260 nm, as determined by SEM and TEM images. The effects of pH, temperature, and initial dye concentrations on dye removal were investigated by batch methods. The results show that adsorption of RhB dye was highly affected by pH value and the higher adsorption capacity was found at pH 2. The Langmuir isotherm model provided a better description for the adsorption process than the Freundlich model, in both linear and nonlinear forms, with good correlation coefficient value (R 2 0.99). The maximum adsorption capacity of RhB was 173.96 mg·g −1 in linear form, and it was 174.04 mg·g −1 in nonlinear form. The adsorption isotherms and thermodynamic parameters revealed that the RhB adsorption by MSNPs–STGC was exdothermic, spontaneous and chemisorption. The kinetic mechanism of adsorption process indicated that the experimental data was fitted with a pseudo-second-order kinetic model very well in both linear and nonlinear forms.