Effect of Applied Electrical Field and the Initial Soil Concentration on Species Recovery During Application of the Electroremediation Process

International audienceElectrokinetic phenomena can be employed for a soil decontamination process generally called electroremediation. The ionic species in solution migrate through a porous medium essentially by electro-osmosis and electromigration. The aim of this work was to contribute to knowledge of this process by studying the effect of some operating conditions on the species recovery through an experimental program. The influence of the electrical field applied to the medium and the initial concentration of the soil solution, in particular, are studied. First, the electrokinetic transport phenomena are presented. Then, the experimental set-up and procedures carried out are described. The set-up consists of a specific electroremediation cell containing a Na-doped kaolinite medium. Chemical reactions were limited by using the sodium as a tracer. The experimental results show the important coupling existing between solution concentration and the electrical current and their influence on both the amount and the rate of transported mass. Moreover, the dependence of the electro-osmotic coefficient on the electrical field applied was demonstrated. The influence of the solution concentration on the electro-osmosis is not obvious, probably due to the light modification of the zeta potential for the system studied

Gradient Clogging in Depth Filtration

We investigate clogging in depth filtration, in which a dirty fluid is ``cleaned'' by the trapping of dirt particles within the pore space during flow through a porous medium. This leads to a gradient percolation process which exhibits a power law distribution for the density of trapped particles at downstream distance x from the input. To achieve a non-pathological clogging (percolation) threshold, the system length L should scale no faster than a power of ln w, where w is the width. Non-trivial behavior for the permeability arises only in this extreme anisotropic geometry.Comment: 4 pages, 3 figures, RevTe

Tissue-enhanced plasma proteomic analysis for disease stratification in amyotrophic lateral sclerosis

Motor Neurone Disease Association (Malaspina/Apr13/817–791). Wellcome Trust support to a parallel study (Pathfinder Award, grant number 103208)

Magnetic resonance imaging application to study of porous media

After characterisation of the medical MRI Bruker BMT 100 scanner in the aim of studying porous media, we showed, by means of a model system that it was possible to determine local and overall porosities. We also used this scanner to study the clogging of a column of glass beads by a suspension of microparticles. This application allowed us to check that 3-D information is accessible by MRI.Après avoir qualifié le spectro-imageur Bruker BMT 100 à usage médical à l'étude des milieux poreux, nous avons montré à l'aide d'un milieu modèle qu'il était possible de déterminer les porosités locales et globales. Nous avons ensuite utilisé cet appareil pour étudier le colmatage d'une colonne de billes de verre par une suspension de microparticules. Cette application nous a permis de vérifier que les informations tridimensionnelles sont accessibles par IRM