Adsolubilization of 2-Naphthol by Binary Mixtures of Cationic and Nonionic Surfactants on Silica

The adsolubilization of 2-naphthol by binary mixtures of cationic and nonionic surfactants on silica was investigated. Two cationic surfactants used were hexadecyltrimethylammonium bromide (HTAB) and 1,2-bis(dodecyldimethylammonio)ethane dibromides (2RenQ), and a nonionic surfactant used was hexaoxyethylenedecyl ether (C10E6). In the single surfactant systems, adsolubilization of 2-naphthol for HTAB and 2RenQ was very similar and was greater than that for C10E6. In the HTAB/C10E6 system the adsolubilization of 2-naphthol was enhanced by surfactant mixtures of HTAB and C10E6 compared to those of single systems. However, in the 2RenQ/C10E6 system the adsolubilization of 2-naphthol by surfactant mixtures of 2RenQ and C10E6 was rather smaller than that of 2RenQ alone but still larger than that of C10E6. It is found that the adsorbed layers of surfactant mixtures formed from different surfactant structures exhibit different adsolubilization behaviors of 2-naphthol, and the alkyl chain length of the surfactants is an important factor to correlate with the adsolubilization of 2-naphthol.