Synergistic Solubilization of Phenanthrene by Mixed Micelles Composed of Biosurfactants and a Conventional Non-Ionic Surfactant

Abstract

This study investigated the solubilization capabilities of rhamnolipids biosurfactant and synthetic surfactant mixtures for the application of a mixed surfactant in surfactant-enhanced remediation. The mass ratios between Triton X-100 and rhamnolipids were set at 1:0, 9:1, 3:1, 1:1, 1:3, and 0:1. The ideal critical micelle concentration values of the Triton X-100/rhamnolipids mixture system were higher than that of the theoretical predicted value suggesting the existence of interactions between the two surfactants. Solubilization capabilities were quantified in term of weight solubilization ratio and micellar-water partition coefficient. The highest value of the weight solubilization ratio was detected in the treatment where only Triton X-100 was used. This ratio decreased with the increase in the mass of rhamnolipids in the mixed surfactant systems. The parameters of the interaction between surfactants and the micellar mole fraction in the mixed system have been determined. The factors that influence phenanthrene solubilization, such as pH, ionic strength, and acetic acid concentration have been discussed in the paper. The aqueous solubility of phenanthrene increased linearly with the total surfactant concentration in all treatments. The mixed rhamnolipids and synthetic surfactants showed synergistic behavior and enhanced the solubilization capabilities of the mixture, which would extend the rhamnolipids application.

The Total Solubility of the Co-Solubilized PAHs with Similar Structures Indicated by NMR Chemical Shift

“…In recent years, many studies have been carried out on the solubilization of PAHs by surfactants [ 23 , 24 , 25 , 26 , 27 , 28 , 29 ]. Aryal et al reported that a single surfactant solution above CMC can enhance the solubility of phenanthrene (Phe) and pyrene (Pyr) in water, and the solubility was linearly proportional to the surfactant concentration [ 24 ].…”

Preparation, Characterization, and Properties of Alkali-Resistant and Hydrolysis-Resistant Silicone Surfactant

“…Compatibility is the basis of the application of surfactants, and the surface properties of ordinary hydrosiloxanes in aqueous solution are limited [34]. In order to improve the use of various surfactants, in the daily preparation of formulations, the form of compounding is often used to integrate various functions of surfactants into one system, so as to achieve a synergistic effect.…”

Rhamnolipid Self-Aggregation in Aqueous Media: A Long Journey toward the Definition of Structure–Property Relationships

“…The characterization of rhamnolipid behavior in aqueous solutions and at the air/water interface also includes a few examples focusing on surfactant mixtures composed of rhamnolipids and other surfactants, either anionic or nonionic ones, namely, sodium dodecylbenzenesulfonate [ 176 , 199 ], sodium dodecylsulfate [ 224 ], sodium laurylethersulfate [ 225 ], lactonic sophorolipid [ 226 ], the aliphatic alcohol ethoxylate surfactant tergitol 15-S-7 [ 227 ], Triton X-100 [ 228 ], and Triton X-165 [ 229 ]. These studies highlight deviations from the ideal mixing pointing toward synergistic interactions between rhamnolipids and sophorolipid [ 226 ], sodium dodecylsulfate [ 224 ], and both Triton surfactants [ 228 , 229 ]. On the other hand, antagonistic interactions take place between rhamnolipids and sodium laurylethersulfate [ 225 ], while the scenario is more complex in the case of dodecylbenzenesulfonate, with an ideal behavior for mixtures containing R1 and deviations from ideality for mixture containing R2 or both R1 and R2 [ 176 ].…”