Association Behavior of anionic Azo dye (AR88) with Surfactants as Seen by Electrical Conductivity Measurements

Abstract

A conductivity technique has been developed, being highly useful for studying the association behavior of acid azo dye (AR88) with surfactants, the conductance of aqueous solutions of (AR88) was measured in the presence of a cationic surfactant, cetyl trimethyl ammonium bromide (CTAB) , nonionic surfactant , Triton X- 100 ( T X – 100 ) and anionic surfactant, sodium dodecyle sulphate (SDS) at different temperatures in aqueous solutions . According to the results, our study of anionic dye - ionic surfactant systems showed that interaction does not exist. The conductivity results obtained for different anionic dye with non ionic and cationic surfactant systems showed a common tendency: when the surfactant concentration of the dye-surfactant system increased, the conductivity values experienced an lower increase than expected on behalf of conductivity values of pure surfactant solution. We used this as an indication of dye - surfactant interaction.  The equilibrium constants and other thermodynamic functions for the process of dye –cationic surfactant ion pair formation were calculated on the basis of a theoretical model. The results have shown that an increase in temperature lower the tendency for ion pair formation as the equilibrium constants decrease with increasing temperature.