Isolation and characterization of dissolved organic matter from the Callovo–Oxfordian formation

Natural iodine in a clay formation: Implications for iodine fate in geological disposals

“…In order to check the validity of such a hypothesis, the concomitant release of organic matter during the acidic extraction step was measured using HCl instead of acetic acid/acetate buffer for carbonate dissolution. Extracted iodine* was very similar (Table 3) and the dissolved organic concentration measured in the solution after the HCl step (25 mg of organic carbon/kg of rock, mg C org kg -1 ) was quite low and in agreement with the concentration found by Courdouan et al (2007), i.e. 12 mg C org kg -1 .…”

Sorption of Np(V) and Np(IV) onto kaolinite: Effects of pH, ionic strength, carbonate and humic acid

“…The swelling properties of clay minerals, their large surface areas and their high retention efficiency towards safety relevant radionuclides are advantageous and make them ideal barriers against radionuclide migration. Most natural clays are closely associated with natural organic matter Schäfer et al, 2003;Courdouan et al, 2007), such as polar low molecular weight organic compounds as well 0883-2927/$ -see front matter Ó 2010 Elsevier Ltd. All rights reserved. doi:10.1016/j.apgeochem.2010.05.008 as humic acid-and fulvic acid-like substances, which can be released from clay under certain conditions.…”

Characterization of low-molecular-weight organic acids isolated from the Toarcian argillite pore water (Tournemire site, France)

“…The extractions were performed with three replicates using crushed materials. Solid-to-liquid ratio of 500 gÁL À1 and 1500 gÁL À1 were tested (Courdouan et al, 2007a(Courdouan et al, , 2007b. For the extractions, 30 mL of extractant solution were transferred into Teflon centrifugation tubes that contained 15 g or 45 g of crushed rock.…”

“…Furthermore, the low hydraulic conductivity and the low water content of deep clay rocks make the pore water sampling difficult without inducing important perturbations (Gaucher et al, 2006). For this reason, the method that was developed to assess the DOM (Courdouan et al, 2007a(Courdouan et al, , 2007b has also been used in this study (details about this method are briefly given in Section 2).…”

“…Most of this organic matter is intimately bound to clay minerals, constituting an insoluble macromolecular fraction called kerogen. Only a small amount of organic matter is present as dissolved organic matter (DOM) in pore water (Beaucaire et al, 2008;Courdouan et al, 2007aCourdouan et al, , 2007bVinsot et al, 2008).…”