Diffusion of lead ions trough the Poznań Clay (Neogene) and through glacial clay

Authors

  • Radosław Mieszkowski Faculty of Geology, University of Warsaw, Al. Zwirki i Wigury 93, PL-02-089 Warszawa, Poland

Keywords:

apparent diffusion coefficient, diffusion in clays, Fick's Law

Abstract

Two main kinds of migration through clays can be distinguished: advection and diffusion. The main force for advective flow is the water pressure gradient, while ionic concentration gradients drive diffusion. In compacted clays the hydraulic permeability is very low, therefore the diffusion process predominates. Clays can be considered as waste repositories. This paper shows characteristics of the diffusion process and the application of this process to modelling of waste migration in clays. Additionally, a new calculation method for the apparent diffusion coefficient using the finite-difference method is given. Experimental, values of the apparent diffusion coefficient Dapp for Poznań Clay and glacial clay are respectively 2.2¸2.6 ´ 10-12 m2 /s and 2.6¸4.4 ´ 10-12 m2 /s.

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Published

2010-03-27

Issue

Vol. 47 No. 1 (2003)

Section

Articles

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