Abstract

The interaction of dyes (crystal violet (CV) and Acid Red 88 (AR 88)) with cationic (Tetradecyltrimethylammonium bromide (TTAB) and nonionic (Triton X 100 (TX-100)) surfactants was explored by means of conductivity, cloud point and UV-visible spectroscopic techniques. For TX-100 and CV mixture, the lowering and increase in CP values were detected in manifestation of employed electrolytes/ 4-aminobenzoic acid and anionic hydrotropes (NaSal and NaBenz) respectively. The CP values of investigating system with electrolytes and HDTs follow the trend: CPNaSal>CPNaBenz>CPNaOAc>CPNaCl>CPNa2SO4>CP4-ABA . The micellization of TTAB + CV was enhanced by the electrolytes while the disfavour of micellization was detected in presence of NaSal at 303.15 K. The CMC values showed U-shaped CMC-T plots in salts media, whereas the CMC increase progressively with the augmentation of temperature in aq. NaSal solution. The binding constant (K_b) of the complexation of TX100-CV was assessed by means of Benesi-Hildebrand (BH) plot while the K_b values were attained to be influenced by the change of solvent composition and experimental temperature. The free energy changes demonstrate that the phase separation and aggregation/binding processes are nonspontaneous and spontaneous in behavior respectively. The changes in enthalpy and entropy values  are indicative of the presence of electrostatic and hydrophobic interactions between surfactant and dye in the employed media. The exclusion of dyes from aqueous solution and wastewater samples were successfully performed using surfactant solution in present of salts media. 

KEYWORDS: Dye, Surfactant, Dye-surfactant interaction, Physico-chemical parameters, Thermodynamics, Electrolytes, Additives.