Quantification of the binding preference of selected dyes at a solid–liquid interface in organized media

SUMMARY

The binding behavior of anionic dyes, acid yellow 17 and acid blue 25, at an activated carbon–liquid interface has been investigated in organized media based on aqueous sodium dodecyl sulfate using differential electronic spectroscopy. The quantification of interactions occurring in the system was realized using a simple physical model, emphasizing the displacement of bound dyes from the carbon surface. The quantities of displaced dyes were comparable; however, acid blue 25 was relatively easily desorbed compared to acid yellow 17. These differences can be attributed to differences in the dye size and hydrophobicity. The model is valid for the premicellar region of the surfactant. The results throw light on some characteristics of solid–liquid inter­faces.