Non-Fickian mass transfer in swelling polymeric non-porous membranes
| Autor: | Abderrahim El Aissaoui, Ali El Afif |
|---|---|
| Rok vydání: | 2017 |
| Předmět: |
Mass flux
Coupling constant Continuum mechanics Cauchy stress tensor Chemistry Diffusion Thermodynamics Filtration and Separation 02 engineering and technology 010402 general chemistry 021001 nanoscience & nanotechnology 01 natural sciences Biochemistry Viscoelasticity 0104 chemical sciences Mass transfer General Materials Science Physical and Theoretical Chemistry 0210 nano-technology Scaling |
| Zdroj: | Journal of Membrane Science. 543:172-183 |
| ISSN: | 0376-7388 |
| DOI: | 10.1016/j.memsci.2017.08.035 |
| Popis: | The aim of this contribution is to formulate a model that investigates the probable occurrence of non-Fickian behavior of mass transport in a viscoelastic polymeric non-porous membrane that swells. Using both continuum mechanics and non-equilibrium thermodynamics approaches, we derive a set of coupled time evolution equations that explicitly incorporate the stress-diffusion mutual interaction. In this 3-D macroscopic model, the trace Π (i.e. the polymer elastic osmotic pressure) and traceless [ σ p ] parts of the polymer second order stress tensor σ p serve as the structural independent state variables. In the one dimensional setting, scaling analysis leads to the emergence of three relevant groups of physical parameters namely the core and surface diffusion Deborah numbers De and De b and a diffusion-stress coupling constant E 0 whose effects are examined for both sorption and permeation unsteady processes. We have solved numerically the 1-D governing equations expressed in the material coordinates and obtained profiles for the solvent concentration, non-Fickian diffusion mass flux, stress distribution, swelling, mass-uptake and stress-uptake. The model is capable of predicting a wide range of non-Fickian behaviors, including the two-stage and overshoot cases; and the confrontation with experimental data selected from the literature shows a good agreement. |
| Databáze: | OpenAIRE |
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