Km. Lipe et al., MICELLAR-ENHANCED ULTRAFILTRATION AND AIR STRIPPING FOR SURFACTANT CONTAMINANT SEPARATION AND SURFACTANT REUSE, Ground water monitoring & remediation, 16(1), 1996, pp. 85-92
Micellar-enhanced ultrafiltration (MEUF) and air stripping were evalua
ted for surfactant-contaminant separation and surfactant recovery. Two
linear alkyl diphenyloxide disulfonate (DPDs) surfactants were evalua
ted with the contaminants naphthalene and trichlorethylene. A separati
on model developed from micellar partitioning principles showed a good
correlation to batch MEUF studies, whereas flux analysis highlighted
concentration polarization effects in relation to hydrophobe length. M
EUF effectively concentrated the surfactant-contaminant system (93 to
99 percent retention); however, this did not result in surfactant-cont
aminant separation. Batch and continuous flow air stripping models wer
e developed based upon air/water ratio, surfactant concentration, and
micellar partitioning; model predictions were validated by experimenta
l data. Sensitivity analyses illustrated the decline in contaminant-su
rfactant separation with increasing surfactant concentration (e.g., TC
E removal efficiency declines from 83 percent to 37 percent as C-16 DP
DS concentration increases from 0 to 55 mM). This effect is greater fo
r more hydrophobic contaminants (naphthalene vs. TCE) and surfactants
with greater solubilization potential (C16-DPDS vs. C-12 DPDS). The re
sulting design equations can account for this effect and thus properly
size air strippers to achieve the desired removal efficiency in the p
resence of surfactant micelles. Proper selection and design of surfact
ant-contaminant separation adn surfactant recovery systems are integra
l to optimizing surfactant-enhanced subsurface remediation.