Work

Determination of diffusion coefficients through gels with non-negligible finite-volume effects in the compartments of the diffusion cell

Year: 2024

Type: article

Abstract: is determined from the slope of the linear plot of the acceptor concentration vs time. However, at long enough times, there is a non-negligible concentration depletion in the donor compartment concomitant to a concentration increase in the acceptor compartment. Accordingly, the accumulation plot bends downwards preventing a linear fitting. This is the case of metals whose solubility (especially depending on pH values) limits the concentration in the donor compartment and the time required to reach concentrations above the limit of quantification in the acceptor compartment implies a non-negligible decrease of the concentration in the donor compartment. In this work, a simple linear regression is shown to provide the diffusion coefficient values from experiments exhibiting finite-volume effects. This expression is validated against rigorous numerical simulation as well as reported values in the literature. Diffusion coefficients of Zn, Ni and Pb in agarose cross-linked polyacrylamide (APA) gels (used in Diffusive Gradients in Thin-Film devices, DGT) are determined under finite-volume effects. The resulting values agree with those obtained under the standard linear regime.

Source: The Science of The Total Environment

DOI: 10.1016/j.scitotenv.2024.177779

Authors: Jordi Sans-Duñó, Joan Cecilia, Josep Galceran, Jaume Puy

Institutions: Universitat de Lleida, Agrotecnio - Centre for Food and Agriculture Research

Language: English

Topic: Diffusion Coefficients in Liquids

Subfield: Spectroscopy

Field: Chemistry

Domain: Physical Sciences

Open Access status: hybrid

Estimated APC paid: $3,990

Funders: Ministerio de Ciencia, Innovación y Universidades, Ministerio de Ciencia e Innovación, Universitat de Lleida