MINIMIZING SURFACTANT LOSSES USING TWIN-HEAD ANIONIC SURFACTANTS IN SUBSURFACE REMEDIATION

The economics of surfactant-enhanced subsurface remediation are affect ed by losses of surfactants due to such phenomena as precipitation, so rption, etc. It is hypothesized that surfactants with twin head groups will exhibit lower losses in the subsurface as compared to single hea d group surfactants while maintaining high solubilization. The contami nant addressed in this research was naphthalene, and the surfactants e valuated were mono- and disulfonated anionics (sodium dodecylbenzenesu lfonate and alkyl diphenyl oxide disulfonates). The results of this re search demonstrated that disulfonates were significantly less suscepti ble to precipitation than monosulfonates and that disulfonates were le ss susceptible to sorption than monosulfonates and also less prone to sorption than nonionic surfactants evaluated in other research. Disulf onates also exhibited greater solubilization of naphthalene than monos ulfonates and slightly lower solubilization than nonionics. Solubility ratios were evaluated on both a molar (MSR) and weight (WSR) basis, a nd corresponding micelle-phase/aqueous-phase partition coefficients (K (m) and K(w)) were reported. This research demonstrated that disulfona te surfactants are less susceptible to losses than other surfactants e valuated and thus are strong candidates for use in surfactant-enhanced subsurface remediation.