NH4-smectite: Characterization, hydration properties and hydro mechanical behaviour

M. Gautier, F. Muller, L. Le Forestier, J. M. Beny, R. Guegan

Research output: Contribution to journalArticle

33 Citations (Scopus)

Abstract

Leachates in waste landfills are characterized by the presence of ammonium ions in large excess. These ammonium ions can be exchanged with the interlayer cations in clay and modify the physical and chemical properties of clay geochemical barriers in waste landfills and drive to environmental problems. The purpose of this study was to understand the hydro-physical changes of a smectite in the presence of ammonium ions. An ammonium smectite was prepared by cation exchange from a natural montmorillonite (Wyoming). The samples were characterized and their properties were compared by the use of a set of complementary techniques (X-ray diffraction, infrared spectroscopy, N2 adsorption-desorption BET technique, thermal analysis, and percolation experiments). The main effect was a modification of the porosity and its network, and reduced crystalline swelling. These effects changed the hydraulic conductivity and macroscopic swelling of the clay. The oedometer experiments, which allow simulating the pressure on small amounts of samples, proved the strong increase of the permeability of NH4-smectite. This last point is of great importance in an environment point of view and raises questions on the impermeability behaviour on the long term of the clay geochemical barriers with the presence of ammonium ions in waste landfills.

Original languageEnglish
Pages (from-to)247-254
Number of pages8
JournalApplied Clay Science
Volume49
Issue number3
DOIs
Publication statusPublished - 2010 Jul

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Keywords

  • Ammonium smectite
  • Clay geochemical barriers
  • Hydraulic conductivity
  • Waste landfill

ASJC Scopus subject areas

  • Geology
  • Geochemistry and Petrology

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