title: Approximation of a radial diffusion model with a multiple-rate model for hetero-disperse particle mixtures.
abstract: An innovative method is proposed for approximation of the set of radial diffusion equations governing mass exchange between aqueous bulk phase and intra-particle phase for a hetero-disperse mixture of particles such as those occurring in suspension in surface water, in riverine/estuarine sediment beds, in soils and in aquifer materials. For this purpose the temporal variation of concentration at several uniformly distributed points within a normalized representative particle with spherical, cylindrical or planar shape is fitted with a 2-domain linear reversible mass exchange model. The approximation method is then superposed in order to generalize the model to a hetero-disperse mixture of particles. The method can reduce the computational effort needed in solving the intra-particle mass exchange of a hetero-disperse mixture of particles significantly and also the error due to the approximation is shown to be relatively small. The method is applied to describe desorption batch experiment of 1,2-dichlorobenzene from four different soils with known particle size distributions and it could produce good agreement with experimental data.
authors.affiliation: Civil and Environmental Engineering Department, University of California, Davis, United States. amassoudieh@ucdavis.edu
authors.forename: Arash
authors.initials: A
authors.lastname: Massoudieh
authors.forename: Daeyoung
authors.initials: D
authors.lastname: Ju
authors.forename: Thomas M
authors.initials: TM
authors.lastname: Young
authors.forename: Timothy R
authors.initials: TR
authors.lastname: Ginn
mesh_terms: D002722:Chlorobenzenes / Q000737:chemistry*; D004058:Diffusion; D008962:Models, Theoretical; D010316:Particle Size; D012989:Soil Pollutants / Q000737:chemistry*
chemical_list: D002722:Chlorobenzenes; D012989:Soil Pollutants; C004726:2-dichlorobenzene