The application of cationic-nonionic mixed micellar media for enhanced solubilization of Direct Brown 2 dye

Abstract The present study reports the enhanced solubilizing power of mixed micellar media in comparison to single micellar media. The solubilization of anionic direct dye, Direct Brown 2 (DB-2) has been investigated in micellar media of cationic surfactants; cetyltrimethyl ammonium bromide (CTAB), cetylpyridinium chloride (CPC) and in mixed micellar media of each with nonionic surfactant Triton X-100 (TX-100) using UV–visible spectroscopy and conductometry. The UV–visible spectroscopy has been used to evaluate the degree of solubilization in terms of binding constant, Kb, Gibbs energy of binding, ΔGb, partition coefficient, Kx, and Gibbs energy of partition, ΔGp. Furthermore, electrical conductivity data, taken at different temperatures, has been employed to find out critical micelle concentration (CMC) and different thermodynamic parameters like enthalpy, ΔHm, entropy, ΔSm and Gibbs energy of micellization, ΔGm of reported surfactants in presence of dye. Results reveal spontaneous nature solubilization and binding of dye in both micellar and mixed micellar solutions of surfactants. The micellar system of CTAB as well as mixed micellar solutions of CTAB/TX-100 are recommended to be used to achieve higher degree of solubilization.