Efficient adsorption of some substituted styrylpyridinium dyes on silica surface from organic solvent media – Analysis of adsorption-solvation correlation

In contrast to aqueous media, adsorption of some styrylpyridinium dyes with electron donating/electron withdrawing substituents on silica scaffold from organic media has been studied. The adsorption has been confirmed through FTIR, SEM, XPS and XRD techniques. Organic solvents have been chosen from a sedimentation time study, which gives an excellent correlation with various solvent parameters. The impacts of solvent environment, substituent, adsorbent dosage, and temperature on the extent and rate of adsorption have been examined along with thermodynamic and kinetic analyses. Second order exothermic mode of adsorption has been observed and physical adsorption has been suggested. Isotherm fitting data suggest monolayer formation of the dye molecules on silica surface. [Display omitted] •Styrylpyridinium dyes adsorbed on silica surface from organic solvents.•Substituents and N-alkyl chains on the dyes influence the extent of adsorption.•Rise in temperature decreases adsorption indicating occurrence of a physical adsorption.•Strong influence of solute-solvent interactions within the dye solutions on the adsorption of dye on to silica surface.•A monolayer formation of the dye molecules on silica surface proposed.