Membrane Uptake Kinetics of Jet Fuel Aromatic Hydrocarbons from Aqueous Solutions Studied by a Membrane-Coated Fiber Technique

Abstract

The absorption of aromatic hydrocarbons from aqueous media is a critical step involved in many biological processes after occupational and environmental exposures to jet fuel. A membrane-coated fiber (MCF) technique was used to study the uptake kinetics. A flow-through system was used to provide a constant concentration for the prolonged permeation experiments. Polydimethylsiloxane (PDMS) and polyacrylate (PA) MCFs were used to study the differential absorptivity of the aromatic compounds between the two membrane materials. The equilibrium absorption amount and a kinetic parameter describing the absorption kinetics were obtained by the regression of the permeation profiles of the aromatic compounds with a mathematical model. The partition coefficients, uptake, and elimination rate constants were determined for six benzene and three naphthalene derivatives. The PDMS/water partition coefficients of the benzene and naphthalene derivatives were linearly correlated with their logKo/w (LogKpdms/w = 0.871LogKo/w − 0.241, R2 = 0.995). The PA/water partition coefficients of the benzene derivatives and the naphthalene derivatives were correlated differently with their logKo/w. The correlation equations for benzene and naphthalene derivatives were LogKpa/w = 0.865LogKo/w + 0.0045, R2 = 0.997 and LogKpa/w = 0.763LogKo/w + 0.911, R2 = 1.00, respectively. These results suggest that the MCF technique can detect subtle differences in molecular interactions of the two group derivatives between the two membrane/water systems and may be used to study the absorption and permeation properties of closely related compounds. Finally, the regression method is a particularly useful tool to determine partition coefficients of very lipophilic compounds.