Effects of Electrolytes on Interfacial and Micelle Properties of C.I. Reactive Orange 16 – Dodecylpyridinium Chloride Binary System

Abstract

Abstract The effect of electrolytes on the interaction between the anionic dye C.I. Reactive Orange 16 and the cationic surfactant dodecylpyridinium chloride was investigated using surface tension measurement in a certain concentration range. The influence of the concentration of electrolyte on critical micelle concentration (CMC) values was observed in the following order; 0.1 M NaCl > 0.5 M NaCl > 1.0 M NaCl. Also, the influence of the electrolyte cations was observed as Na+ > Mg2+ > K+. An increase on CMC values of dye-surfactant solution with increasing electrolyte concentration is explained as charge screening and also the decrease in these values for higher concentration of electrolyte is attributed to the change of micelle shape. Furthermore this change is due to ionic polarizability, valency and hydrated radius. Using Rubingh's regular solution theory, the values of micellar interaction parameters (β), were found as negative in all studied mixtures.