الملخص الإنجليزي
study investigates the solubilization enhancement of pyrene and naphthalene by anionic, nonionic and modified nonionic surfactants. Surfactants selected in this work consist of an anionic sodium dodecyl sulfate (SDS), a series of alkyl ether sulfates (CS 130, CS 230 and CS 330) and a nonionic polyoxyethylene(23) Lauryl ether (Brij 35). Molar solubilization ratios (MSR) of naphthalene in SDS, CS 130, CS 230, CS 330 and Brij 35 were found to be 0.0649, 0.0935, 0.1104, 0.1389 and 0.2751, respectively, whereas those obtained for pyrene were 0.0098, 0.0129, 0.0192, 0.0231 and 0.0383, respectively. All the obtained values were close to the reported literature values. The higher solubilizing power of Brij 35 micelles compared to SDS and the CS series is probably related to the lower critical micelle concentration of the non-ionic surfactant.
Dodecyl ether sulfate surfactants showed higher solubilization enhancement than SDS. Moreover, increasing the EO from 1 to 3 in CS 130, CS 230 and CS 330, resulted in an increase of the MSR of naphthalene and pyrene.
The effect of mixing CS surfactants: CS 130, CS 230 and CS 330 with Brij 35 on the solubilization of pyrene was also investigated at different CS-Brij 35 molar fraction compositions. Similar positive mixing effect was observed for all mixed surfactants systems, indicating that the solubilization enhancement is mainly dictated by Brij 35.
The mixing effect on the solubilization of naphthalene CS230-Brij35 mixed micelles at different molar fraction compositions was also investigated. A positive mixing effect on the solubilization was also observed.
In all surfactant mixtures (CS 130-Brij 35, CS 230-Brij 35, CS 330-Brij 35), the experimental CMCs were lower than the corresponding ones calculated by assuming ideal mixing behavior. This strong negative deviation in the CMC is due to a strong molecular interaction between ether sulfate and Brij 35
