Correlating solvation-adsorption phenomena of some styrylpyridinium dyes on SDS modified silica surface in organic media

Sodium dodecyl sulfate modified silica (SDSMS) surface has been used to study the adsorption of some cationic styrylpyridinium dyes from organic solvent media using ultraviolet-visible (UV-Vis) spectrophotometric technique. The modifications of silica surface and subsequent modification through adsorption of dye molecules on the surface have been characterized by Fourier transform infrared (FT-IR), X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), X-ray photoelectron spectroscopy (XPS), UV-Vis spectroscopy and zeta potential measurements. Kinetics of adsorption and consequent thermodynamic parameters have been studied and discussed. The isotherm modeling, choice of solvents from sedimentation analysis, and other common adsorption related parameters such as amount of adsorbent dosage, contact time, adsorption efficiencies have been reported. The influences of solvents and the substituents present on the dye molecules, on the rate of adsorption have been discussed. A pictorial model of adsorption process has been suggested based on the experimental results.