An Electrodynamics-Based Model for Ion Diffusion in Microbial Polysaccharides
An electrodynamics-based model was formulated for simulation of ion diffusion in microbial polysaccharides with fixed charges and electrostatic double layers. The model extends a common multicomponent ion diffusion model that is based on irreversible thermodynamics under a zero ionic charge flux condition, which is only applicable to the regions without fixed charges and electrostatic double layers. An efficient numerical procedure was presented to solve the differential equations in the model. The model well described key features of experimental observations of ion diffusion in negatively charged microbial polysaccharides including accelerated diffusive transport of cations, exclusion of anions, and increased rate of cation transport with increasing negative charge density. The simulated diffusive fluxes of cations and anions were consistent with a classic exchange diffusion concept in negatively charged polysaccharides at the interface of plant roots and soils; and the developed model allows to mathematically study such diffusion phenomena. Numerical simulations also showed that ion diffusive transport within a bacterial cell wall polysaccharide may induce an ionic current that compresses or expands the bacterial electrostatic double layer at the interface of the cell wall and bulk solution.
- Research Organization:
- Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC05-76RL01830
- OSTI ID:
- 15020874
- Report Number(s):
- PNNL-SA-41435; KP1301010; TRN: US200521%%406
- Journal Information:
- Colloids and Surfaces. B, Biointerfaces, Vol. 38
- Country of Publication:
- United States
- Language:
- English
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