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 heterodisperse mixture of particles such as occur 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.

Transfer of PCBs from Microplastics under Simulated Gut Fluid Conditions Is Biphasic and Reversible

“…To describe sorption to soils, sediments, or polymer particles, two schools of modeling exist, one using diffusion models and the other using first-order multiple compartment models. 36,37 Whereas diffusion models are better equipped to relate parameters to actual physical properties of sorbents and adsorbates, including microplastics, 38 first order models have remained popular as they are much easier to apply in larger modeling frameworks, such as fate models or plastic-inclusive bioaccumulation models. 7,15,17,18 Furthermore, biphasic or triphasic multiple component first order models have a long history in understanding and describing HOC sorption to sediments and soils.…”

“…To describe sorption to soils, sediments, or polymer particles, two schools of modeling exist, one using diffusion models and the other using first-order multiple compartment models. , Whereas diffusion models are better equipped to relate parameters to actual physical properties of sorbents and adsorbates, including microplastics, first order models have remained popular as they are much easier to apply in larger modeling frameworks, such as fate models or plastic-inclusive bioaccumulation models. ,,, Furthermore, biphasic or triphasic multiple component first order models have a long history in understanding and describing HOC sorption to sediments and soils. − We used a model simulating the exchange of chemicals between plastics, water, micelles and food components, dependent on initial conditions and kinetic rate parameters, while fully accounting for sorption reversibility and possible biphasic sorption behavior. A schematic overview of the model is provided in SI Figure S1.…”

Microplastics’ journey into the gut : human exposure to microplastics and associated chemicals

“…To describe sorption to soils, sediments or polymer particles, two schools of modeling exist, one using diffusion models and the other using first-order multiple compartment models. 64,65 Whereas diffusion models are better equipped to relate parameters to actual physical properties of sorbents and adsorbates, including microplastics, 66 first order models have remained popular as they are much easier to apply in larger modeling frameworks, such as fate models or plastic-inclusive bioaccumulation models. 25,26,32,46 Furthermore, biphasic or triphasic multiple component first order models have a long history in understanding and describing HOC sorption to sediments and soils.…”