title: Prediction of mass-transfer coefficient for solute transport in porous media.
abstract: Several previously reported laboratory studies related to transport of solutes through packed columns were utilized to develop predictive relationships for mass-transfer rate coefficient. The data were classified into two groups: those obtained under rate-limited mass transfer between mobile and immobile water regions (physical nonequilibrium conditions), and those derived from rate-limited mass transfer between instantaneous and slow sorption sites (sorption nonequilibrium conditions). The mass-transfer coefficient in all these studies was obtained by fitting breakthrough data to a transport model employing a first-order rate limitations with a "constant" mass-transfer coefficient, independent of flow conditions. This study demonstrated that the mass-transfer coefficient in these models is dependent on system parameters including pore-water velocity, length-scale, retardation coefficient, and particle or aggregate size. Predictive relationships were developed, through regression analysis, relating mass-transfer coefficient to residence time. The developed relationships adequately estimated previously reported field mass-transfer values. Successful simulations of field desorption data reported by Bahr [J. Contam. Hydrol. 4 (1989) 205] further demonstrate the potential applicability of the developed relationships.
authors.affiliation: Department of Civil Engineering, College of Engineering, United Arab Emirates University, P.O. Box 17555, Al-Ain, United Arab Emirates. m.maraqa@uaeu.ac.ae
authors.forename: M A
authors.initials: MA
authors.lastname: Maraqa
mesh_terms: D005544:Forecasting; D008962:Models, Theoretical; D010316:Particle Size; D012989:Soil Pollutants / Q000032:analysis*; D014872:Water Movements; D014873:Water Pollutants / Q000032:analysis*
chemical_list: D012989:Soil Pollutants; D014873:Water Pollutants