Adsolubilization by mixtures of ionic and non-ionic surfactants

摘要

The adsolubilization of 2-naphthol by surfactant mixtures of ionic and non-ionic surfactants has been investigated for three systems; sodium dodecyl sulfate(SDS)-hexaoxyethylene decyl ether(C10E6)-alumina, hexadecyltrimethylammonium bromide (HTAB)-C10E6-silica, and 1,2-bis(dodecyldimethylammonio)-ethane dibromide (2RenQ)-C10E6-silica. For three systems, the interaction parameters estimated from mixed critical micelle concentrations are –3.4 for both SDS-C10E6 and HTAB-C10E6 and –1.5 for 2RenQ-C10E6, suggesting that the interaction between SDS and C10E6 as well as that between HTAB and C10E6 is stronger than that between 2RenQ and C10E6 in mixed micelle formation. In the SDS-C10E6-alumina system where only SDS shows an appreciable adsolubilization, the adsolubilization becomes greater with an increase in the SDS content in the initial mixtures. On the other hand, the ratios of adsolubilized amount to surfactant adsorbed amount decrease when the SDS content in the initial mixtures increases. In the cationic surfactant-C10E6-silica systems where each surfactant such as HTAB, 2RenQ, or C10E6 shows an appreciable adsolubilization, the ratios of adsolubilized amount to surfactant adsorbed amount are greater at some mixture compositions compared to those of single surfactants. In particular, the effect of chemical structure of cationic surfactant on the adsolubilization is also discussed.